r- * • ’1 Z7 k)vLt/fjlq lyUl/liJIyivLIu i ■' . ,' OX J X T O T H T C\ f xA7 JlJlI 1 olU-LUljri *y T T T F ~r’ ”v I1.A.11ARE jVLJLL ST1ONS AND ANSWERS. ts in the form of questions and answers tding the standard works, often is at a >e remembered, and is equally puzzled to the manner in which the questions T will loss 1 whei coult A INEW QUESTION-COMPEND SERIES. ESSENTIALS OF DISEASES OF THE EAR. By E. B. Gleason, S. B., M. D Surgeon in Charge of the Nose, Throat, and Ear Department of the Northern Dispensary of PhiladelZ phia, etc. Price, 81.00. Interleaved for notes, $1.25. This latest addition to the Saunders Compend Series accurate?’ epre- sents the modern aspect of otological science. While small in cg. r<ass, it nevertheless is logically and capably written; it comprises upward of 100 pages with about 89 illustrations, most of which are from original sources. Essentials of Physiology. 5th edition. Illustrated. Revised and enlarged by H. A. Hare. M. D. (Price, $1.00 net.) Essentials of Surgery. 5th edition, with Appendix on Antiseptic Surgery... 90 illustrations. Bv Ed- ward Martin, Essentials of Anate 180 illustration M. D. Essentials of Medl organic. By L Essentials of Obste larged. 75 illus TON, M. D. Essentials of Path< thousand. 46 i Semple, M. D. Essentials of Matt Prescription-W Morris, M. D. Essentials of Pra< Morris, M. D. NATION. Illust M. D. 3d editioi Formula, select Wm. M. Powel 12.00.) Essentials of Disea letter-press cut: By Henry W. Stelwagon, iu. x>. ($1.00 net.) OTHER VOLUMES IN THE COMPEND SERIES. Essentials of Gynaecology. 4th edition. With 6211- lustrations. By Edwin B. Cragin, M. D. Essentials of Minor Surgery, Bandaging, and Vene- real Diseases. 78 illustrations. By Edward Martin. M. T>. ology, and Hy- Arm'and Sem- ie, and Throat. |tion. By Ed- Ileason, M. D. 4th thousand. Colored “ Vo- istrations. By , 75 cents.) -Cohen, M. D., rated. (Price, ?y L. E. Sayre. ations and five V.Ball.M. I). Insanity. 48 M.D. ustrations. By ■, 81.00 net.) 5 illustrations, d Edward S. Lawrance,M. D. jPrice, Cloth, $1.00 per copy, except when otherwise noted. ♦** For sale by all booksellers, or mailed to any address on receipt of price. Full descriptive catalogue eent ou application. At the present time, when the student is forced by the rapid progress of medical science to imbibe an amount of knowledge which is far too great to permit of any attempt on his part to master it, a book which contains the “ essentials ” of a science in a concise yet readable form must of necessity be of value. Intended to assist Students to put together the knowledge they have already acquired by attending lectures. Saunders’ New Aid Series of Manuals. A MANUAL OF SURGERY, GENERAL AND OPERATIVE. BY JOHN CHALMERS DaCOSTA, M.D., Demonstrator of Surgery, Jefferson Medical College, Phila- delphia ; Chief Assistant Surgeon, Jefferson Medical College Hospital; Surgical Registrar, Phila- delphia Hospital, etc. This work is now recommended as a preliminary text-book by over forty-five medical colleges of the United States and Canada. One very handsome volume of over 800 pages, with 188 Illustra- tions in text and 13 Plates in Colors and Tints. (Double Number.) PRICE, CLOTH, $2.50 net. A new manual of the Principles and Practice of Surgery, intended to meet the demands of students and working practitioners fora medium- sized work, which will embody all the newer methods of procedure detailed in the larger text-books. The work has been written in a concise, practical manner, and especial attention has been given to the most recent methods of treatment. Illustrations have been freely used to elucidate the text. A Syllabus of Lectures ON THE PRACTICE OF SURGERY, Arranged in Conformity with Tie American Text-Book of Surgery. BY NICHOLAS SENN, M.D., Ph.D., Professor of Surgery in Rush Medical College, Chicago, and in the Chicago Polyclinic. PRICE, $2.00. Sent post-paid on receipt of price. This latest work of its eminent author, himself one of the contributors to the “ American Text-Book of Surgery,” has been carefully prepared from his unrivalled course of lectures to the students of Rush Medical College, and is intended for use as a key or supplement to the larger work. The subjects are carefully grouped in tabular form, those diseases and operations of a similar character and requiring similar treatment being classed to- gether, thereby greatly condensing the material and lightening the labors of the student. The Syllabus will prove also of exceptional value as a surgical diagnosis and as an aid to the surgeon in selecting the operations indicated. ESSENTIALS OF PHYSIOLOGY. Since the issue of the first volume of the Saunders Question=Compends, OVER 160,000 COPIES of these unrivalled publications have been sold. This enormous sale is indisputable evidence of the value of these self-helps to students and physicians. SAUNDERS’ QUESTION-COMPENDS, NO. 1. ESSENTIALS OF PHYSIOLOGY ARRANGED IN THE FORM OF QUESTIONS AND ANSWERS, PREPARED ESPECIALLY FOR STUDENTS OF MEDICINE. BY HOBART AMORY JjARE, M.D., PROFESSOR OF THERAPEUTICS AND MATERIA MEDICA IN THE JEFFERSON MEDICAL COLLEGE OF PHILADELPHIA; PHYSICIAN TO THE JEF- FERSON MEDICAL COLLEGE HOSPITAL; MEMBER OF THE ASSOCIATION OF AMERICAN PHYSICIANS. FOURTH EDITION, THOROUGHLY REVISED AND ENLARGED. CONTAINING A SERIES OF HANDSOME PLATE ILLUSTRATIONS TAKEN FROM THE CELEBRATED “ICONES NERVORUM CAPITIS” OF ARNOLD. PHILADELPHIA: W. B. SAUNDERS, 925 Walnut Street. 1897. Copyright, 1897, by W. B. SAUNDERS. Press of W. B. Saunders, Philadelphia. PREFACE TO FOURTH EDITION. At the request of the publisher, and with the con- sent of Dr. Hare, the work of revising this book for the fourth edition has been undertaken by Dr. J. H. Raymond. The original text has almost wholly been retained, alterations being made only where necessary to bring the subject under consideration abreast with the teachings of the day. V PREFACE TO FIRST EDITION. At the present time, when the student is forced by the rapid progress of medical science to imbibe an amount of knowledge which is far too great to permit of an attempt on his part to master it, any book which contains the “ essentials ” of a science in a concise yet readable form must of necessity be of value. The trite saying that “there is no short road to knowledge ” is, of course, as true as it is old, and for this reason many of the medical profession have looked with disfavor on books of this character, as being the means by which students might attempt the shorter path. No one desires more than the writer that the depth and scope of medical education may be increased, but in his belief the evil at present in existence consists in the fact that medical institutions, by granting a degree too early, make the short road to knowledge the only one which the student with the average amount of cerebral gray matter can possibly travel. The evil lies with the small amount of time required for the obtaining of the degree, not with those books which are called into existence by the short- ness of the medical curriculum. VII VIII PREFACE. The usefulness of arranging the subject in the form of questions and answers will, the writer thinks, be apparent, since the student, in reading the standard works on Phys- iology, often is at a loss to discover the important points to be remembered, and is equally puzzled when he attempts to formulate ideas as to the manner in which the question could be put in the examination-room. A manual of this character is in no one way intended to supplant any of the text-books, but to contain, as its title declares, the essence of those physiological facts with which the average student must be familiar. After considerable thought, it has been considered advisable to exclude points which may be called purely anatomical, and which deprive some of the smaller books on Physiology of the space which might otherwise be occupied by purely physiological statements. The results reached every day by physiological experimenters are many of them so contradictory that no attempt to give individual opinions or teachings has been attempted, the statements made being supposed to represent those facts most generally accepted and taught. The student will, therefore, find statements which are not in accord with those taught by his instructor, and it is for this purpose that the interleaved edition has been published, in order that individual teachings may be noted and remembered. In the compilation of the facts here rehearsed, the standard works of Landois, Yeo, Foster, Dalton, Baker, Hermann, and Chapman have all been consulted. CONTENTS. PAGE Proteids 18 Carbo-hydrates 20 The blood 21 Coagulation of blood 28 The heart 31 Respiration 48 The nervous mechanism of respiration .... 53 Digestion .54 The stomach GO Pancreatic digestion 66 The liver 68 Absorption .73 Animal heat ... 76 The kidneys 81 The urine 90 The skin 95 Secretion 97 The mammary glands 98 The bodily metabolism 98 General view of the most important substances used as food 99 Milk 99 The muscles 104 The nervous system 112 The physiology of the spinal nerves . . . . .117 The physiology of the cerebro-spinal nervous system . .118 The functions of the spinal cord 122 The medulla oblongata .128 The cranial nerves . 141 IX X CONTENTS. PACE The special senses 145 The sensibility of the skin 146 The sense of taste 147 The sense of smell 148 The sense of sight 149 Hearing 158 The voice and speech 161 The sympathetic nerve 165 Generation and development 167 Generative organs of the female 168 The male sexual organs 171 Development 178 The development of organs 179 Vertebral column and cranium ..... 179 Extremities 180 Heart and bloodvessels . 180 Nervous system ........ 181 Eye 182 Ear 183 Nose. . 183 Alimentary canal and organs ...... 183 The foetal circulation ....... 184 PLATE I. DESCRIPTION OF THE PLATES. PLATE I. POSITION AND COURSE OF THE CRANIAL NERVES WITHIN THE SKULL. This plate shows the course of the cranial nerves within the skull and through the foramina of the dura mater, and the plexuses of nerves accompanying the arteries at the base of the brain. The skull being removed by a horizontal section from the glabella to the external occipital protuberance, the brain and tentorium cere- belli are taken out, leaving in view the arteries and roots of the nerves at the base of the brain. A. —Superior part of the helix of the right and left ears. B. —Skin and adipose tissue. C. —Frontal portion of occipito-frontalis muscle. D. —Temporal muscle. E. —Occipital portion of the occipito-frontalis muscle, a. Frontal artery, b. Supraorbital artery, c. Anterior, and d, posterior temporal arteries, e. Occipital artery. F. —Frontal bone. f. Frontal crest, g. Groove for the superior lon- gitudinal sinus. Gr.—Parietal bone ; h, its anterior, and i, posterior inferior angles. H. —Squamous portion of the temporal bone. I. —Tabular portion of the occipital bone. k. Internal occipital pro- tuberance. K. —Crista galli. L. —The dura mater covering the anterior cranial fossa, cerebral ridges, and digital impressions, I, and the cribriform plate of the ethmoid bone, ni. n. Anterior portion of the falx cerebri with the superior longitudinal sinus, o. XI XII DESCRIPTION OF THE PLATES. M. —Middle cranial fossa, covered by dura mater, p. Posterior cli- noid processes, q. Dorsum ephippii. r. Anterior clinoid processes, s. Pituitary body and infundibulum, t. Dia- phragm of the sella Turcica, u. Superior petrosal sinus. N. —Posterior cranial fossa, v. Falx cerebelli. w. Torcular Hero- phili. x. Lateral sinuses, y. Mastoid emissary vein. z. Opening of the lateral sinus into the bulb of the internal jugular vein. O. —Foramen magnum. I*.—Lower portion of the medulla oblongata, a. Anterior median fissure. 0. Posterior median fissure. 7. Central gray mat- ter with central canal of the spinal cord. 5. Anterior, and e, posterior gray horns. £. Pyramids. ». Lateral columns. S. Posterior columns. Q.—Vertebral arteries, c. Anterior spinal artery, x. Posterior in- ferior cerebellar artery. A. Posterior spinal artery. lar artery, v. Branches to the pons. £. Anterior inferior cerebellar artery. 0. Internal auditory artery, it. Superior cerebellar artery, p. Posterior cerebral artery. It.—Internal carotids, a. Posterior communicating artery, r. An- terior choroid artery, ». Middle cerebral artery. <p. Ante- rior cerebral artery. Anterior communicating artery. I. —Olfactory nerve. II. —Optic nerve. III. —Motor oculi nerve. IV. —Pathetic nerve. V. —Trifacial nerve. VI. —Abducens nerve. VII. —Facial nerve. 1. Its greater, and 2, lesser portions. VIII. —Auditory nerve. IX. —Glosso-pharyngeal nerve. X. —Pneumogastric nerve. XI. —Spinal accessory nerve. 3. Its cranial, and 4, spinal roots. XII. —Hypoglossal nerve. The carotid and vertebral arteries are accompanied by sympathetic plexuses, derived from the superior and inferior cervical, and some- times from the superior thoracic ganglia. PLATE II. DESCRIPTION OF THE PLATES. XIII PLATE II. COURSE OF THE CRANIAL NERVES THROUGH THE FORAMINA OF THE SKULL, AND IN THE ORBIT AND TEMPORAL FOSSA. On the right side the semilunar ganglion, recurrent branches of the first, second, and third divisions of the trifacial nerve, and the upper- most nerves of the orbit are in view. To the left are seen the course of the cranial nerves through the foramina of the skull, the deeper nerves of the orbit, and the nerves of the temporal fossa. The calvarium being removed, the brain, together with the carotid and vertebral arteries, is taken out. To the right the dura mater and tentorium cerebelli are in their natural position, the lateral and superior petrosal sinuses being opened, but the meningeal layer of the dura mater of the middle cranial fossa is removed, as is also the roof of the orbit, so that not only the triangular plexus, semilunar ganglion, the first, second, and third divisions of the trifacial, with their recurrent branches, but also the course of the supraorbital, lachrymal, and pathetic nerves may be seen. To the left, the dura mater which covers the base of the skull is re- moved. The orbit, temporal fossa, tympanic cavity, internal auditory meatus, and facial canal are exposed to view. The supraorbital, lachrymal, and pathetic nerves are cut away, and the levator palpebrae superioris and superior rectus muscles are divided and turned aside. To the left, therefore, are seen the course of the cranial nerves through the foramina of the skull; the position and course of the optic, nasal, superior branches of the motor oculi and the abducens nerves ; the origin and course of the buccal, deep temporal, masse- teric and anterior auricular nerves ; and finally the connections of the facial and auditory nerves ; the course of the chorda tympani through the tympanic cavity, and the position of the greater and lesser superficial petrosal nerves on the upper surface of the petrous por- tion of the temporal bone. A.—F., and a—g, indicate the same structures as in the preceding plate. G.—Inferior margin of the parietal bone. XIV DESCRIPTION OF THE PLATES. H.—Squamous portion of the right temporal bone. h. Left cerebellar fossa, i. Foramen magnum, k. Left innominate process. I. Left jugular process, m. Jugular notch, n. Left poste- rior, and. o, anterior condyloid foramina. K.—Petrous portion of the left temporal bone. p. Sigmoid fossa. q. Mastoid foramen. r. Mastoid cells, s. Semicircular canals partly visible and partly cut away. t. Internal audi- tory meatus, w. Tympanic cavity, v. Head of the malleus. w. Incus, x. Posterior lacerated foramen, y. Apex of the petrous portion of the temporal bone. z. Petro-sphenoidal ligament. Ii.—Sphenoid bone. a. Clivus Blumenbachii. H. Posterior clinoid processes, y. Olivary process. S'. Left great wing of the sphenoid bone partly cut away. e. Foramen spinosum. £. Foramen ovale. ». Foramen rotundum. Roots of the right lesser wing of the sphenoid bone. c. Anterior lacerated foramen, x. Optic foramen, between the roots of the lesser wing of the sphenoid bone. M. —Cribriform plate of the ethmoid bone. X. Anterior ethmoidal foramen. N. —Inner surface of the temporal muscle. O. —Upper border of the external pterygoid muscle. I*.—Condyle of the inferior maxilla. Q. —Dura mater, p. Anterior portion of the falx cerebri and of the superior longitudinal sinus, v. Opening for the passage of the trunk of the trifacial nerve. Posterior portion of the falx cerebri, o. Right lateral sinus, tt. Superior petrosal sinus, p. Dura mater covering the posterior cranial fossa. R. —Lower portion of the medulla oblongata. S. —Vertebral artery. On the left it may be seen beneath the con- dyloid portion of the occipital bone ; and on the right it is seen passing through the dura mater. T. —Internal carotid, a-. The second, r, third, and v, fourth flexures of the left internal carotid. U. —Middle meningeal artery. On the left side it is divided near the foramen spinosum. The anterior branch, and poste- rior branch of the middle meningeal artery, which last sends a small petrosal branch into the anterior part of the petrous portion of the temporal bone. V. —Posterior deep temporal artery, branch of the internal maxillary. DESCRIPTION OF THE PLATES. XV W. —Ophthalmic artery. 4- Lachrymal artery. a>. Muscular branches. aa. Ciliary arteries, bb. Supraorbital artery, cc. Ethmoidal artery, dd. Ophthalmic artery continuing its course to the inner canthus. X. —Pituitary body and part of the infundibulum. Y. —The eyeball. Z. —External rectus muscle. AA. Internal rectus muscle. BB. Superior oblique muscle. CC. Levator palpebrae superioris muscle. DD. Superior rectus muscle. I. —Olfactory nerve. 1. Olfactory tract, and 2, bulb of the left side. 3. Filaments of the right olfactory nerve, ensheathed by the dura mater, entering the nasal cavity through the cribriform plate of the ethmoid bone. II. —Optic nerve. 4. Its sheath. On the left side the course of the optic nerve may be seen as far as the eyeball. III. —Motor oculi nerve. 5. Superior branch, going to the superior rectus and levator palpebrae superioris muscles. 6. Inferior branch. IV. —Right pathetic nerve. 7. Communicating branch of the first division of the fifth to the pathetic nerve, which runs in its sheath, from whence it soon passes to the internal branch of the supratrochlear nerve. 8. Distribution of the pathetic nerve to the superior oblique muscle. V. —Trunk and triangular plexus of the trifacial nerve. 9. Semi- lunar (or Gasserian) ganglion of the fifth pair. 10. Small accessory ganglion, sometimes found in the triangular plexus near the semilunar margin of the semilunar ganglion. 11. First division of the trifacial. 12. Recurrent branch, which runs around the pathetic and divides into two branches, (13), which go as far as the lateral sinus. 14. Lachrymal nerve. 15. Supraorbital nerve. 16. Frontal nerve. 17. Supratrochlear nerve. 18. Two filaments which go to the supratrochlear nerve. 19. Nasal nerve. 20. Sensory root of the ophthalmic ganglion. 21. Long ciliary nerves. 21*. Short ciliary nerves, coming from the ophthalmic gang- lion. 22. Nasal nerve. 23. Infratrochlear nerve. 24. Second division of the trifacial. 25. Recurrent branch of the second division of the fifth. 25*. Its junction with the recurrent branch of the third division of the fifth. 26. Third division of the trifacial. On the left side it may be seen XVI DESCRIPTION OF THE PLATES. passing through the foramen ovale. 27. Recurrent branch of the third division of the fifth nerve, which runs within the cranium along the posterior margin of the middle menin- geal artery, joins the recurrent branch of the second division of the fifth (25*), and gives off a lesser anterior petrosal branch (27*), which accompanies the anterior petrosal artery into the anterior part of the petrous portion of the temporal bone, while it goes to the posterior part of the petrous por- tion of the temporal bone with the posterior branch of the middle meningeal artery, or a special posterior petrosal branch of this artery. The origin of this recurrent nerve is shown in the first figure of the fourth plate. 28. Superior root of the auriculo-temporal nerve. 29. Masseteric nerve. 30. Posterior deep temporal nerve. 31. External pterygoid nerve. 32. Buccal nerve. 33. Anterior deep temporal nerve. VI. —Abducens nerve. On the left side its course may be seen on the outer side of the internal carotid and through the ante- rior lacerated (34) foramen. 35. Distribution of the abducens nerve to the external rectus muscle of the eye. VII. —Facial nerve. 36. Its greater, and 37, lesser portions. 38. The internal, and 39, external communications of the facial with the auditory nerve. 40. Geniculate ganglion. 41. Greater superficial petrosal nerve. 42. Chorda tympani nerve. VIII. —Auditory nerve. IX. —Glosso-pharyngeal nerve. 43. Lesser superficial petrosal nerve. X. —Pneumogastric nerve. 44. Superior vagal ganglion, or ganglion of the Root. XI. —Spinal accessory nerve. XII. —Hypoglossal nerve. PLATE III. DESCRIPTION OF THE PLATES. XVII PLATE III. THIS WITH PLATE IV. GIVES AN INNER AND POSTERIOR VIEW OF THE CRANIAL AND CERVICAL NERVES, AND THE CAROTID AND VERTEBRAL ARTERIES, BOTH WITHIN AND OUTSIDE OF THE CRANIUM, AND OF THE SPINAL CANAL. The distribution of the nerves of the nasal septum, course of the posterior cranial and superior cervical nerves, and the position of the superior cervical ganglion and sympathetic plexuses on the arteries of the head are illustrated in this diagram. The right side of the head and half of the cerebrum, cerebellum, medulla and spinal cord are removed by a perpendicular section ; the skull and the bodies of the cervical vertebrae, together with the rectus capitis anticus major and minor and longus colli muscles. The basilar process of the occipital and posterior part of the body of the sphenoid bones are removed ; the spinal and carotid canals, and the condyloid and posterior lacerated foramina are opened, the osseous and carti- laginous nasal septum cut away, and the mucous membrane of the pharynx and palate and the genio-hyo-glossus muscle are either partly or wholly removed. Therefore the following structures are seen: firstly, the spinal canal covered by the dura mater, and the vertebral vessels and roots of the cervical nerves ; secondly, the posterior cranial fossa and the recurrent branch of the vagus nerve, the hypoglossal, spinal accessory, vagus and glosso-pharyngeal nerves, both within and outside of the cranium, and the superior cervical ganglion ; thirdly, the cavities of the pharynx and larynx, hard and soft palate and the tongue with its nerves ; finally, the common carotid lying between the pharynx and vertebrae, the internal and external carotids and the sympathetic plexuses accompanying the carotid and vertebral arteries. A.—Gr.—Cervical vertebrae from the first to the seventh, a. Arch of the vertebrae sawed through the centre, b. Left apex of the spinous processes, c. Posterior root of the transverse pro- cesses. H.—Occipital bone. d. Left condyle, e. Anterior condyloid foramen. f. Tabular portion of the occipital bone. g. External, and XVIII DESCRIPTION OF THE PLATES. h, internal occipital protuberances, i. Foramen magnum. k. Posterior cranial fossa, covered by dura mater. I. —Interior portion of parietal bone. K. —Temporal bone. I. Petrous portion, m. Carotid canal, n. In- ternal auditory meatus, o. Squamous portion of the temporal bone covered by dura mater. L. —Sphenoid bone. p. Its body partly removed, q. Sphenoidal sinus, r. Lesser wing. s. Greater wing, covered by dura mater, t. Middle cranial fossa, w. Optic foramen. JM.—Frontal bone. v. Its vertical plate, w. Frontal sinus, x. Or- bital plate, covered by dura mater, y. Digital impressions and cerebral ridges, z. Anterior cranial fossa. N. —Cribriform plate of the ethmoid, a. Crista galli sawed through the centre. O. —Nasal bone. P. —Palate process of the superior maxillary. &. Anterior palatine canal. Q. —Horizontal plate of the palate bone. y. Posterior palatine canal. R .—Inferior maxillary, sawed through the centre. 5. Genial tubercles. S. —Incisor teeth. T. —Left superior canine tooth. TJ.—Hyoid bone. e. Body. £. Greater cornu, w. Lateral thyro- hyoid ligament. V.—Trapezius, W, splenius capitis, X, biventer cervicis, Y, semi- spinalis colli, and Z, interspinales muscles, a. Rectus capi- tis posticus major, and B, minor muscles. r.—Orbicularis oris muscle. A.—Genio-hyo-glossus muscle, partly removed so that the distribution of the lingual and hypoglossal nerves, the course of the ranine and sublingual arteries, and the site of the sublingual gland and Wharton’s duct may be seen. 9. Internal, and i, ex- ternal layers of fibres of the genio-hyo-glossus. E. Longitu- dinal, and z, inferior transverse fibres of the lingualis, H, genio-hyoid, and ©, mylo-hyoid muscles. J. —Anterior belly of the digastric. K. —Levator palati, A, superior, M, middle, and N, inferior constric- tors of the pharynx. S. Longitudinal fibres of the oesophagus. DESCRIPTION OF THE PLATES. XIX o. —Trachea, x. Rings of the trachea. rr. Larynx. X. Cricoid, and p, thyroid cartilages, v. Epiglottis. £. Ventricle of the larynx, o. Arytaenoideus muscle. p. —Isthmus of the thyroid gland. 2.—Wharton’s duct. T. Sublingual gland. T.—Tongue, w. Circumvallate, and />, fungiform papillae. <r. Root of the tongue. t> —Palate, t. Soft palate, v. Mucous membrane of the hard pal- ate. <}>. Incisive papilla. X. —Roof of the pharynx, %. Pharyngeal orifice of the Eustachian tube. 4- Mucous glands of the roof of the pharynx. ai. Eustachian eminence. Y. —Left posterior nares, n. Membrane of the nasal septum. AA.—Dura mater, aa. Anterior, and bb, posterior part of the falx cerebri, cc. Tentorium cerebelli. dd. Posterior end of the superior longitudinal sinus, ee. Superior petrosal sinus. ff. Sigmoid portion of the lateral sinus. BB. —Dura mater of the spinal cord. CC.—Vertebral artery, gg. Its first, AA, second, and u, third flexures. DD.—Inferior thyroid artery. EE.—Common carotid. FF.—External carotid. GG.—Superior thyroid artery. HH.—Lingual artery, kk. Sublingual artery. II. End of the ranine artery. II.—Facial artery. KK.—Ascending pharyngeal artery, mm. Pharyngeal, and nn, ba- silar branches. (LL.) —Internal maxillary artery. 00. Arteries of the nasal sep- tum. pp. Descending palatine artery. MM.—Internal carotid, qq. Cowper’s flexure, which is sometimes found. rr. Its first, ss, second, tt, third, and uu, fourth flexures, vv. Posterior communicating artery, ww. Anterior choroid artery, xx. Middle cerebral or Sylvian artery. yy. Anterior cerebral artery, zz. Ethmoidal branch of the ophthalmic artery, anastomosing with the nasal branches of the internal maxillary. NN .—Trunk of the vertebral vein, which receives the cervical part of the vertebral sinus, (OO), between the fifth and sixth cervical vertebrae. PP.—Vertebral vein accompanying the XX DESCRIPTION OF THE PLATES. vertebral artery through the vertebral foramina and con- nected by many transverse branches with the vertebral sinus. QQ. —Anastomosis of the superior and inferior thyroid arteries. I. —Olfactory nerve. 1. Olfactory filaments of the nasal septum in- closed in fibrous sheaths. II. —Optic nerve. III. —Motor oculi nerve. IV. —Pathetic nerve. V. —Trifacial nerve. First division. 2. Nasal nerve. Second division. 3. Nasal nerves. 4. Branch to the hard pal- ate, passing through the anterior palatine canal. 5. Pharyngeal nerves. Third division. 6. Lingual nerve. 7. Lingual branches. VI. —Abducens nerve. VII. —Facial nerve. VIII. —Auditory nerve. IX. —Glosso-pharyngeal nerve. 8. The petrous ganglion. 9. Junc- tion with the jugular branch of the superior cervical gang- lion. 10. Branch joining the superior pharyngeal branch of the vagus. 11. Pharyngeal branches. 12. Lingual branch. 13. Branches going to the circumvallate papillse. 14. Branches supplying the mucous membrane between the circumvallate papillae and the epiglottis. X. —Pneumogastric nerve. 15. Superior vagal ganglion. 16. Junc- tion with the jugular branch of the superior cervical gang- lion. 17. Recurrent branch of the vagus. 18. Its lesser division going to the occipital sinus, and the greater branch, 19, going to the sigmoid sinus. 20. Superior pharyngeal branch. 21. Inferior vagal ganglion, or ganglion of the Trunk. 22. Inferior pharyngeal branch passing to the pha- rynx between the internal and external carotids. 23. Supe- rior laryngeal nerve. 24. External branch. 25. Its junc- tion with the sympathetic nerve. 26. Internal branch of the superior laryngeal nerve. 27. Branches distributed to the mucous membrane of the larynx and epiglottis. 28. Junction with the inferior laryngeal nerve. 29. Vagus nerve in the neck. 30. Inferior laryngeal nerve. 31. Its inoscu- lation with the sympathetic. 32. (Esophageal branches. 33. Tracheal branches. 34. Laryngeal branch. DESCRIPTION OF THE PLATES XXI XI. —Spinal accessory nerve. 35. Its internal, and 36, external divisions. XII. —Hypoglossal nerve. 37. Its inosculation with the first cervical nerve and superior cervical ganglion. XII*.—Branches of the hypoglossal to the genio-hyo-glossus and genio-hyoid muscles. XIII. —XIX.—Seven superior cervical nerves. 38. Their anterior, and 39, their posterior roots. 40. Ganglia on the posterior roots of the cervical nerves. 41. Anterior division of the first, second, third, and fourth cervical nerves. 42. Communi- cating branches of these nerves, constituting the cervical plexus. 43. Principal root of the phrenic nerve, coming from the anterior division of the fourth cervical nerve. XX. —Superior cervical ganglion. 44. Carotid nerve. 45. Its internal inferior branch. 46. Carotid plexus. 47. Cavernosus plexus, from which are given off branches to the abducens (48), to the ophthalmic division of the fifth (49), and to the cerebral and ophthalmic arteries (50). 51. Jugular nerve, forming a junction with the glosso-pharyngeal and vagus nerves. 52. Nerve uniting the hypoglossal and first cervical nerves. 53. Trunk inosculating with the cervical plexus. 54. Junction of the superior cervical and inferior vagal ganglia. 55. Sym- pathetic trunk to the external carotid, which is often com- posed of two or three branches. 56. Superior part of the trunk, from which branches go to the external carotid (57), and to the carotid plexus (58). (59.) Inferior part of the trunk, which gives branches to the facial (60), lingual (61), and thyroid arteries (62). 63. Branch going to the carotid ganglion (64), which sends very delicate branches to the common carotid artery (65). 66. Branches to the external branch of the superior laryngeal, and 67, to the phrenic nerves. 68. Superior cardiac nerve, arising from the cer- vical sympathetic trunk by several roots. 69. Its commu- nication with the inferior laryngeal nerve. 70. Middle cardiac nerve, uniting with the superior cardiac nerve. XXI. —Upper portion of the first thoracic ganglion. 71. Sympathetic branches to the vertebral artery. 72. Sympathetic plexus on the vertebral artery. 73. Sympathetic plexus on the inferior thyroid artery. XXII DESCRIPTION OF THE PLATES. PLATE IV. Fig. I. This diagram shows the trifacial, lateral nasal, and palatine nerves, the spheno-palatine and otic ganglia, and the facial nerve in the facial canal, seen from the inside. The skull and posterior part of the head, parts of the neck, and most of the petrous portion of the temporal and the sphenoid bones are removed ; the facial canal and tympanic cavity are opened to view, the internal carotid artery and carotid canal, the cartilaginous portion of the Eustachian tube, roof of the pharynx and levator palati muscle, the nasal septum, and posterior part of the hard palate are cut away ; the pterygo-palatine fossa and canals are shown, and the mucous membrane of the nose is partly removed. Therefore the internal auditory meatus, the facial canal, the osseous portion of the Eustachian tube and the tympanic membrane, the ear ossicles and their muscles, the course of the facial nerve through the petrous portion of the temporal bone, the inner surface of the trunk of the trifacial nerve and its ganglion, with its first, second, and third divisions, the otic and spheno-palatine ganglia, the nerves of the palate, and the lateral wall of the nose with the distribution of the nerves of the first and fifth pairs to its mucous membrane are shown. A. —Petrous portion of the temporal bone. a. Bottom of the inter- nal auditory meatus, and b, interior of the facial canal, c. Superior margin, and d, inner surface of the petrous portion of the temporal bone. B. —Sphenoid bone. e. Foramina spinosum,/, ovale, and g, rotun- dum opened from within, h. Pterygoid process, with the internal plate partly removed, i. Hamular process, k. Inner extremity of the lesser wings. I. Optic foramen. C. —Lower part of the vertical plate of the frontal bone. m. Frontal sinus. D. —Ethmoid bone. n. Posterior ethmoidal cells, o. Cribriform plate, p. Anterior ethmoidal foramen, g. Left nasal fossa. E. —Left nasal bone. F. —Palate process of the superior maxillary bone. G. —Ramus of the inferior maxillary bone. r. Angle of the inferior maxillary bone. PLATE IV. XXIII DESCRIPTION OF THE PLATES. H. —Tensor palati muscle turned forward. I. —Internal pterygoid muscle. K.—Tensor tympani, and L, stapedius muscles. M. —Upper end of the external carotid artery. N. —Temporal artery. O. —Internal maxillary artery, s. Inferior dental artery, t. Mid- dle meningeal artery, u. Descending palatine artery, v. Nasal artery cut. I*.—Posterior auricular artery. Q.—Dura mater, upper surface of the petrous portion of the temporal bone, and the trifacial, pathetic, motor oculi and abducens nerves. R.—Inner surface of the tympanic membrane, and the ear ossicles, w. The head, x, neck, and y, the manubrium of the malleus, z. The incus, a. Stapes. S. —Lateral wall of the nasal cavity. &. The superior, y, middle, and J, inferior turbinated bones, t. The superior, £, mid- dle, and «, inferior meatuses of the nose. S'. Lateral carti- lage, and i, ala of the nose. x. Mucous membrane covering the superior and upper part of the middle turbinated bones removed to show the course of the olfactory filaments through the grooves of the ethmoidal turbinated bones. A. Mucous membrane of the anterior inferior regions of the nares is removed, showing the distribution of the nasal branches of the fifth nerve, p.. Mucous membrane of the inferior meatus, y. Mucous glands. T. —Mucous membrane of the hard and soft palate. U. —The tongue. £. Lingual papillae, o. Glands at the root of the tongue. V. —Parotid gland. (I.)—Olfactory nerve. 1. Olfactory filaments of the wall of the nose which have fibrous sheaths and run through grooves in tin- upper and middle turbinated bones, forming a network ami sending delicate branches to the mucous membrane. II. —Optic nerve. III. —Motor oculi nerve. IV. —Pathetic nerve. V. —Trifacial nerve. 2. Common trunk. 3. Its lesser, and 4, its greater roots. 5. Semilunar ganglion. 6. First or ophthal- mic division of the fifth nerve. 7. Nasal nerve. 8. Branch to the nasal septum severed (vid. Plate III., 2). 9. Branch to the lateral surface of the nares. 10. External XXIV DESCRIPTION OF THE PLATES. branch {vid. Plate VIII., 7). 11. Second or superior maxil- lary division of the fifth. 12. Naso-palatine nerve. 13. Posterior palatine nerves. 14. The anterior palatine nerve. 15. Superior, and 16, inferior nasal nerves. 17. Spheno- palatine ganglion (Meckel’s). 18. Greater deep petrosal nerve. 19. Greater superficial petrosal. 20. Vidian nerve. 21. Ascending branches, and 22, branch from the ganglion to the nose. 23. Third or inferior maxillary division of the fifth. 24. Recurrent branch piercing the otic ganglion and accompanying the middle meningeal artery within the cranium {vid. Plate II., 27). 25. Auriculo-temporal nerve, arising by two roots, between which passes the middle men- ingeal artery. 26. Inferior dental nerve. 27. Lingual nerve. 28. Junction of the chorda tympani and lingual nerves. 29. Internal pterygoid nerve. 30. Branches to the tensor palati, and 31, to the tensor tympani muscles, coming from the pterygoid nerve and piercing the otic gang- lion. 32. Otic ganglion. 33. Lesser superficial petrosal, coming from the tympanic nerve. 34. Sympathetic root of the otic ganglion. 35. Branch to the tensor tympani leaving the otic ganglion. 36. Branch proceeding to the auriculo-temporal nerve. VI. —Abducens nerve. VII. —Facial nerve. 37. Genu of the facial nerve. 38. Greater superficial petrosal nerve. 39. Junction with the lesser superficial petrosal nerve, which arises from the tympanic nerve. 40. Branch to the stapedius muscle. 41. Chorda tympani. Fig. II. Showing, from behind, the course of the facial, glosso-pharyngeal, pneumogastric, spin'al accessory, and hypoglossal nerves in the cranial bones, and of the auricular branch of the vagus in the petrous portion of the right temporal bone. The occiput of the right side of the head is removed by a transverse section, opening the condyloid and posterior lacerated foramina, and the facial canal and auricular fissure from behind. Therefore the course of the hypoglossal, spinal accessory, vagus and glosso-pharyngeal nerves through the foramina of the skull, the ganglia of the vagus and glosso-pharyngeal nerves, the auricular branch of the vagus and its junction with the facial nerve are seen. DESCRIPTION OF THE PLATES. XXV A. —Occipital bone. a. Basilar process, b. The condyle, c. Anterior condyloid foramen. B. —Body of the sphenoid bone covered by dura mater. C. —Petrous portion of the temporal bone. d. Its superior internal margin, e. Inner surface, f. Internal auditory meatus, g. Cavity of the tympanum, A, mastoid cells, and i, posterior part of the facial canal from behind, k. Canal for the chorda tympani. I. Auricular fissure, m. Mastoid process, n. Styloid process, o. Stylo-mastoid foramen, p. Upper part of the head of the malleus, q. The body, and r, the short process of the incus. D. —Posterior surface of the ear. E. —Skin and adipose tissue. F. —Sterno-cleido-mastoid muscle, cut perpendicularly. Gr.—Posterior belly of the digastric muscle, also divided. H. —Posterior surface of the roof of the pharynx, s. Acinous mucous glands of the pharynx, t. Superior constrictor muscle of the pharynx. I. —Internal carotid. K. —Internal jugular vein, cut off above so that the course of the auricular branch of the vagus nerve may be seen. L. —Occipital, and M, posterior auricular arteries. VII. —Facial nerve. 1. Chorda tympani. 2. Posterior auricular nerve. 3. Small branches going to the posterior belly of the digastric muscle. VIII. —Auditory nerve. IX. —Glosso-pharyngeal nerve. 4. The petrous ganglion. 5. Branch joining the auricular branch of the vagus. 6. Pharyngeal branches of the glosso-pharyngeal nerve. X. —Pneumogastric nerve. 7. Superior vagal ganglion. 8. Recur- rent branch of the vagus, divided transversely. 9. Auricular branch of the vagus. 10. Its communication with the facial nerve in the facial canal. 11. Its communication with the posterior auricular nerve. 12. Its auricular branches. 13. Inferior vagal ganglion. XI. —Spinal accessory nerve. 14. Its internal, and 15, its external divisions. XII. —Hypoglossal nerve. XIII. —Carotid nerve and the upper part of the superior cervical ganglion. XXVI DESCRIPTION OF THE PLATES. PLATE V. ILLUSTRATION OF CRANIAL AND CERVICAL NERVES, THE NERVES ACCOMPANYING THE CAROTID AND VERTEBRAL ARTERIES, BOTH WITHIN AND OUTSIDE OF THE CRANIUM, AND THE SPINAL CORD SEEN FROM THE OUTSIDE. This plate shows, firstly, the origin of the cranial and cervical nerves of the right side, with the exception of the first and sixth pairs ; secondly, the course of the cervical nerves between the cervical vertebrae, the spinal ganglia, the breaking up of the nerves into their anterior and posterior divisions, and their inosculations amongst themselves and with the superior cervical ganglion ; then the course and part of the distribution of the third, fourth, fifth, ninth, tenth, eleventh, and twelfth pairs of nerves outside of the cranium, and the roots of the ophthalmic and spheno-palatine ganglia and the sympathetic plexuses on the vertebral and internal carotid arteries. To show these parts the scalp, occipital, frontal, parietal, mastoid and petrous portions of the temporal, the greater and lesser wings of the sphenoid, the malar and posterior portions of the inferior maxillary bones of the right side, the spinous and transverse processes, and the arches of the cervical vertebrae, together with the skin and superficial muscles of the neck, the muscles and vessels of the face and temples, and the thyroid and salivary glands are removed ; the intervertebral, condyloid, and posterior lacerated foramina, spinal canal, internal auditory meatus, carotid canal, Eustachian tube, pterygo-palatine fossa, Vidian canal and the antrum of Highmore are opened ; the right half of the cerebellum and cerebrum, together with the corpus striatum, is removed ; while the spinal cord, medulla oblongata, pons Varolii, crus cerebri, right optic thalamus and corpora quadrigemina remain intact. A.—G. —Cervical vertebrae from the first to the seventh, a. Left portion of the spinous processes, b. Right transverse pro- cesses. c. Anterior, and d, posterior roots of the transverse processes. TT.—Occipital bone. e. Its tabular portion, f. External occipital protuberance, g. Right condyle, h. Anterior condyloid foramen, i. Posterior lacerated foramen. P L A T E V. DESCRIPTION OF THE PLATES. XXVII I.—Petrous portion of the right temporal bone. k. The posterior, I, external, and m, superior semicircular canals, n. Cochlea. o. Fenestra ovalis, and p, fenestra rotunda, q. Base of the styloid process. K. —Body of the sphenoid bone. r. Clivus Blumenbachii. s. In- ternal plate of the pterygoid process. L. —Parietal bone sawed through near the sagittal suture. M. —Frontal bone. X.—Superior maxillary bone. t. Antrum of Highmore. O.—Inferior maxillary bone. I*.—Molar, and Q, bicuspid teeth of the upper jaw. R. —Right inferior canine tooth. S. —Greater cornu of the hyoid bone. T. —The trapezius, U, splenius, V, biventer cervicis, W, Semi- spinalis colli, X, interspinales, Y, rectus capitis posticus major, and Z, minor muscles of the left side. AA.—Right rectus capitis anticus major muscle. BB. and CC.—Inferior, DD, middle, and EE, superior con- strictor muscles of the pharynx. FF.—Stylo-pharyngeus muscle. GG.—The stylo-hyoid, HH, genio-hyo-glossus, JJ, genio-hyoid, and KK, mylo-hyoid muscles. EL.—The hyo-glossus muscle, partly cut away to show the course of the lingual artery and lingual branch of the glosso-pharyngeal nerve. MM.—The thyro-hyoid, and NN, crico-thyroid muscles. OO.—Levator palati muscle. PP.—Tendon of the tensor palati muscle. QQ .—Levator anguli oris muscle. RR .—The levator palpebrae superioris, SS, superior, and TT, in- ferior recti, and UU, inferior oblique muscles of the eye. VV.—The eyeball. WAV.—The upper, and XX, lower lids, cut through perpendicu- larly. YY.—The tongue, u. Fungiform papillae. v. Mucous membrane of the cheek. —The larynx. A.—Trachea. B.—(Esophagus. r.—Eustachian tube. A.—Common carotid. E.—External carotid. XXVIII DESCRIPTION OF THE PLATES. Z.—Superior thyroid artery, w. Superior laryngeal artery, x. Thy- roid branches severed, y. Muscular branches. H. —Lingual artery. ®.—Origin of the facial artery. I. —Ascending pharyngeal artery. k.—Internal maxillary artery, z. Posterior dental artery, a. Infra- orbital artery. /3. Descending palatine artery, y. Nasal artery. A.—Internal carotid. J.—Its first, s, second, £, third, and n, fourth flexures. M. —Ophthalmic artery. N. —The posterior communicating, o, anterior choroid, rr, middle cerebral, and p, anterior cerebral arteries of the right side. 2. Anterior cerebral artery of the left side. T.—Vertebral artery. 3. Its first, i, second, and x, third flexures. A. Spinal branches. yt.. The right, and v, left posterior inferior cerebellar arteries. £. Internal auditory artery, o. Right superior cerebellar artery, or. The right, and p, left posterior cerebral arteries, a-. Inferior thyroid artery. Y.—Dura mater of the spinal cord. <p.—Tentorium cerebelli. -r. Superior petrosal sinus. x.—Dura mater of the brain. v.—Cervical spinal cord. n.—Medulla oblongata, u. Striae medullares. <{>. Sinus rhomboidalis. AA.—Cerebellum. Inner surface of the left hemisphere. Y. Arbor vitae, ai. Fourth ventricle, aa. Valve of Vieussens, or su- perior medullary velum. S3. The inferior, yy, middle, and superior cerebellar peduncles, ee. Right side of pons. EB.—Right crus cerebri. rr.—Corpora quadrigemina. 41. Right optic thalamus. EE.—Fornix. ££. Right crus of the fornix. «». Foramen of Monro. S3-. Body of the fornix, u. Septum lucidum. zz.—Corpus callosum divided longitudinally through the centre, xx. Its genu, AA, body, and /x/x, splenium. hh.—Inner surface of the left cerebral hemisphere, w. The frontal, oo, parietal, and nr, occipital lobes, pp. Gyrus fornicatus. II.—Optic nerve. 1. Its origin from the optic thalamus. 2. Optic tract. 3. Orbital portion of the optic nerve. DESCRIPTION OF THE PLATES. XXIX III. —Motor oculi. 4. Superior branch to the superior rectus and levator palpebrae superioris muscles. 5. Inferior branch. 6. Motor root of the ophthalmic ganglion. 7. Branch to the inferior oblique muscle. IV. —Pathetic nerve. 8. Its origin. 9. Course of the pathetic nerve above the pons and external to the crus cerebri. 10. Its course along the upper border of the ophthalmic division of the trifacial nerve. V. Trifacial nerve. 11. Its lesser, and 12, greater roots. 13. Semi- lunar ganglion. 14. First or ophthalmic division of the fifth. 15. Supraorbital nerve. 16. Lachrymal nerve cut away. 17. Nasal nerve. 18. Sensory root of the ophthalmic ganglion. 19. Long ciliary nerves. 20. Ophthalmic gang- lion. 21. Its sympathetic root. 22. Short ciliary nerves. 23. The superior, and 24, inferior fasciculi of ciliary nerves. 25. Second division or superior maxillary nerve. 26. Subcutaneous malae nerve severed. 27. Infraorbital nerve. 28. Posterior dental nerves. 29. Anterior dental nerve severed. 30. The inferior palpebral, lateral nasal, and superior labial nerves. 31. Naso-palatine nerve. 32. Spheno- palatine ganglion. 33. Greater superficial petrosal nerve. 34. Greater deep petrosal nerve. 35. Posterior superior nasal nerve. 36. Palatine nerves. 37. Third division or inferior maxillary nerve. 38. Auriculo-temporal nerve. 39. Masseter nerve. 40. Posterior deep temporal nerve. 41. Buccal nerve. 42. Inferior dental nerve. 43. Lingual nerve, the lingual part of it being reflected to show the distribution of the hypoglossal nerve. 44. Lingual branches. VI. —Abducens nerve severed. VII. —Facial nerve. 45. Genu of the facial nerve. 46. Its junction with the greater superficial petrosal nerve. VIII. —Auditory nerve. IX. —Glosso-pharyngeal nerve. 47. Petrous ganglion. 48. Tym- panic nerve. 49. Branch joining the carotid nerve. 50. Branches to the fenestra rotunda, and 51, to the fenestra ovalis. 52. Branch going to the Eustachian tube. 53. Lesser superficial, and 54, lesser deep petrosal nerves. 55. Branches uniting with the branches of the superior cervical ganglion, and with branches from the inferior vagal ganglion. 56. Carotid plexus. 57. Branches running between the XXX DESCRIPTION OF THE PLATES. internal and external carotids to the carotid ganglion. 58. Pharyngeal branches. 59. Branches to the stylo-pharyngeus muscle. 60. Lingual branches. X. —Pneumogastric nerve. 61. Superior vagal ganglion. 62. Branch to the carotid plexus. 63. Inferior vagal ganglion. 64. Superior laryngeal nerve. 65. External branch to the crico- thyroid muscle. 66. Junction of this branch with a filament from the superior cervical ganglion. 67. Internal branch of the superior laryngeal nerve. 68. Trunk of the vagus in the neck. 69. Inferior or recurrent laryngeal nerve, sending branches to the oesophagus, trachea, and larynx. XI. —Spinal accessory nerve. 70. Its spinal, and 71, cranial roots. 72. Course of the spinal root between the roots of the pos- terior division of the first cervical nerve. 73. Its internal division, uniting with the trunk of the vagus. 74. Its ex- ternal division. XII. —Hypoglossal nerve. 75. Its roots passing over the vertebral artery. 76. A branch joining the first cervical, and 77, the vagus nerves. 78. Descendens noni branch. 79. Thyro- hyoid branch. 80. Branch to the genio-hyoid, and 81, the stylo-glossus muscles. 82. Branches to the hyo-glossus, and 83, the genio-hyo-glossus and the muscles of the tongue proper. XIII. —First cervical nerve. 84. Its posterior root, which is crossed by the spinal accessory nerve. 85. The posterior division cut away. 86. Anterior division. 87. Muscular branch. XIV. —Second cervical nerve. 88. Posterior root. 89. Spinal gang- lion. 90. Posterior division severed. 91. Anterior division. 92. Branch joining the first cervical nerve and superior cer- vical ganglion. 93. Branch to the rectus capitis anticus major muscle. 94. Descending communicating branch. 95. Communicans noni branch. XV. —Third cervical nerve. 96. The posterior root divided and reflected to show the course of the spinal root of the spinal accessory nerve. 97. Branch joining the posterior root of the fourth cervical nerve. 98. Spinal ganglion. 99. Pos- terior division severed. 100. Anterior division. 101. Junc- tion with the superior cervical ganglion. 102. Communicana noni branch. 103. Ansa hypoglossi. DESCRIPTION OF THE PLATES. XXXI XVI.—Fourth cervical nerve. 104. Posterior root divided. 105. Its junction with the posterior root of the fifth cervical nerve. 106. Spinal ganglion. 107. Posterior division severed. 108. Anterior division. 109. Branch to the longus colli muscle. 110. Trunk of the anterior division severed. 111. Posterior root. 112. Spinal ganglion. 113. Posterior division severed. 114. Anterior division severed. 115. Roots of the phrenic nerve. XVII.—Fifth cervical nerve. XVIII.—Sixth cervical nerve. XIX.—Seventh cervical nerve. XX. —Posterior root of the eighth cervical nerve. XXI. —Superior cervical ganglion. 116. Sympathetic branches to the carotid ganglion. 117. Carotid ganglion. 118. Fila- ments to the common and external carotid arteries. 119. Branch to the carotid plexus. 120. Superior external branch of the carotid nerve, from which the greater deep petrosal nerve is given off. 121. Inferior internal branch of the carotid nerve. 122. Sympathetic nerves on the internal carotid within the cranium. XXII. —Cervical sympathetic trunk. 123. Vertebral branch from the inferior cervical and superior thoracic ganglia. 124. Sympathetic plexus on the vertebral artery. XXXII DESCRIPTION OF THE PLATES. PLATE VI. COURSE OF SOME OF THE NERVES OF THE FIFTH PAIR THROUGH THE ORBIT, SUPERIOR MAXILLARY BONE AND TEMPORAL FOSSA; OF THE FACIAL AND CHORDA TYM- PANI THROUGH THE PETROUS PORTION OF THE TEM- PORAL BONE; OF THE POSTERIOR DIVISIONS OF THE CERVICAL NERVES IN THE MUSCLES OF THE NECK, AND THE SYMPATHETIC NERVES ACCOMPANYING THE EXTER- NAL CAROTID ARTERY AND ITS BRANCHES. This plate, which shows the nerves of the right side of the head, illustrates first the course of the lachrymal from the first, subcutaneous make and infraorbital from the second, and the lingual and mylo- hyoid from the third division of the fifth ; then the facial nerve through the facial canal, and chorda tympani through the tympanic cavity, and the distribution of the posterior divisions of the cervical nerves to the muscles of the neck, and finally the sympathetic plexus around the external carotid, and the roots of the submaxillary gang- lion . The skull is divided by a perpendicular section near the sagittal suture, and the right side of it, with the dura mater, is removed ; the greater wing of the sphenoid, malar, and periorbital bones, most of the right half of the superior and inferior maxillae, the squamous portion and external part of the mastoid process of the temporal bone, the platysma, sterno-cleido-mastoid, sterno-hyoid, sterno-thyroid, omo- hyoid, and external pterygoid muscles are cut away ; and the second and third layers of cervical muscles are turned aside. Therefore, the following structures are partly or wholly exposed to view : the external surface of the brain, the parts of the eye adjacent to its outer wall, the frontal and maxillary sinuses, the parts of the oral cavity and temporal fossa adjoining the inner surface of the inferior maxillary bone, the tympanic membrane and mastoid cells, submaxil- lary and thyroid glands, larynx, trachea, pharynx, and oesophagus, and the muscles of the neck with the vessels and nerves. A.—G. —Cervical vertebrae from the first to the seventh, a. Trans- verse processes, b. Superior, and c, inferior articular pro- cesses. PLATE VI DESCRIPTION OF THE PLATES. XXXIII H. —Occipital bone. d. Left upper part of the tabular portion of the occipital bone. e. Lower part of the tabular portion of occi- pital bone. I. —Temporal bone. f. Mastoid foramen. g. Mastoid cells. h. Facial canal, i. Styloid process, k. Stylo-mastoid foramen. I. Membrana tympani. m. Incus, n. Malleus, o. Eus- tachian tube. K. —Sphenoid bone. p. Body. q. External pterygoid plate, r. Sphenoidal cells, s. Foramen spinosum. t. Foramen ovale. The foramen rotundum is covered by dura mater. L. —Frontal bone. u. Its orbital, and v, vertical plates, w. Frontal sinus. M. —Right parietal bone, sawed through near the sagittal suture. N. —Superior maxillary bone. x. Inner wall of the antrum of High- more. y. Canine tooth, z. Bicuspid teeth, a. Molar teeth. O. —Inferior maxillary bone, sawed through perpendicularly near the right canine tooth ($). P. —Insertion of the sterno-cleido-mastoid muscle. Q. —Spleuius capitis muscle cut transversely near its insertion (y). R. Trachelo-mastoid muscle similarly cut (S'). S. Com- plexus and biventer cervicis muscles, detached and turned aside from their origins. T. Semispinalis colli. U. Upper part of the multifidus spinse. V. Rectus capitis posticus major. W. Inferior, and X, superior oblique muscles. Y. Rectus capitis lateralis. Z. Intertransversales muscles. A.—Rectus capitis anticus major, b. Scalenus anticus. r. Posterior belly of the digastric. A. Stylo-hyoid. E. Stylo-glossus. Z. Internal pterygoid. H. Anterior belly of the digastric. ®. Mylo-hyoid. I. Genio-hyoid. K. Hyo-glossus. A. Thyro-hyoid. M. Crico-thyroid. N Inferior constrictor of the pharynx, e. Its cricoid, and C, thyroid origins. S. Levator palpebrae superioris and superior rectus muscles. o External rectus muscle, n. Inferior rectus muscle. p. Inferior oblique muscle. 2. Eyeball. T. Lachrymal gland. Y. Dura mater. ». Lateral sinus. 4>. Cerebrum. &. The frontal, «, parietal, x, temppro sphenoidal, and X, occipital lobes, p,. External part of the fissure of Sylvius. v. Its vertical, and £, horizontal limbs. DESCRIPTION OF THE PLATES. XXXIV X. The tongue, o. Mucous membrane of the cheek. v. Sublingual gland, n. Submaxillary gland. *Wharton’s duct. AA. Thyroid gland. BB. Larynx, tt. Thyroid cartilage, p. Cricoid cartilage. CC. (Esophagus. DD. Upper part of the common carotid. EE. External carotid. FF. Superior thyroid artery, a-. Its thyroid branches. (jrGr. Lingual artery. HH. Facial artery, r. Ascending palatine artery, v. A muscular branch. <p. Submental artery. II. Occipital artery. /. Descending cervical branches. 1F. Menin- geal branch. a>. Distribution of the artery to the occiput. KK. Posterior auricular artery. EE. Temporal artery. MM. Internal maxillary artery, aa. Inferior dental artery, bb. Middle meningeal artery, cc. Posterior dental artery, dd. Infraorbital artery, ee. Descending palatine and nasal arteries. NN. Internal carotid, ff. Lachrymal branch of the ophthalmic artery, gg. Network of the middle cerebral arteries. OO. Profunda cervicis artery. PP. Vertebral artery, hh. Its first, and it. second flexures. QQ. Profunda cervicis vein. RR. Vertebral vein. kk. Deep venous plexus of the neck. SS. Occipital vein. II. Mastoid emissary vein. TT. Lateral veins of the brain, emptying into the lateral sinus. UU. Superior veins of the brain, emptying into the superior longi- tudinal sinus. VV. Veins of the fissure of Sylvius. WW. Ophthalmic vein. XX. Inferior ophthalmic vein. III. —Motor oculi nerve. 1. Branch to the inferior oblique muscle. (V.)—Trifacial nerve. First division. 2. Supraorbital nerve. 3. Lachrymal nerve. 4. Its superior, and 5, inferior branches. 6. Second division of the fifth. 7. Subcutaneous malae nerve. 8. Malar branch severed. 9. Orbital branch going to the lachrymal gland and often joining the inferior branch of the lachrymal nerve. 10. Infraorbital nerve. 11. Posterior dental nerve. 12. Anterior dental nerve. 13. Trunk of the infraorbital nerve DESCRIPTION OF THE PLATES. XXXV passing through the infraorbital canal. 14. Pharyngeal nerve. 15. Third division of the fifth. 16. Buccal nerve. 17. External pterygoid nerve. 18. Anterior deep temporal nerve. 19. Posterior deep temporal nerve. 20. Masseter nerve. 21. Roots of the auriculo-temporal nerve, surround- ing the middle meningeal artery. 22. Trunk of this nerve divided. 23. Inferior dental nerve, divided near the inferior dental foramen. 24. Mylo-hyoid nerve. 25. Its branches to the mylo-hyoid and the anterior belly of the digastric muscles. 26. Lingual nerve. 27. Junction of the lingual and chorda tympani nerves. 28. Branches to the mouth. 29. Branches to the inferior maxillary ganglion. 30. Sub- lingual branch. 31. Lingual branches. 32. Submaxillary ganglion. 33. Its motor root coming from the chorda tympani. 34. Its sympathetic root. 35. Branches to the submaxillary gland, and 36, to Wharton’s dnct. 37. Branches joining the lingual nerve. VII.—Facial nerve. 38. Chorda tympani. 39. Its origin, and 40, course between the malleus and incus. 41. Posterior au- ricular nerve. 42. Branches to the digastric, and 43, stylo- hyoid muscles. 44. Trunk of the facial nerve divided. (X).—Pneumogastric nerve. 45. Superior laryngeal nerve. 46. In- ternal branch. 47. External branch, going to the crico- thyroid muscle. 48. Trunk of the vagus nerve in the neck. 49. Inferior or recurrent laryngeal nerve. 50. (Esophageal branches. 51. Tracheal branches. 52. Laryngeal branch. XII.—Hypoglossal nerve. 53. Curve of the hypoglossal. 54. De- scendens noni branch, and 55, branch to the thyro-hyoid muscle divided. 56. Branch to the genio-hyoid muscle. 57. Branches to the hyo-glossus muscle. 58. Branches to the genio-hyo-glossus muscle and to the muscles of the tongue proper. (XIII.)—First cervical nerve. 59. The internal branch of the pos- terior division, sending filaments to the rectus capitis pos- ticus major and minor, obliquus capitis inferior, and com- plexus muscles. 60. The external branch of the posterior division, sending a branch to the obliquus capitis superior and rectus capitis lateralis muscles, and a branch over, (61), the obliquus capitis superior to the splenius capitis and trachelo-mastoid muscles. XXXVI DESCRIPTION OF THE PLATES. (XIV.)—Second, cervical nerve. 62. Anterior division. 63. Its ascending, and 64, descending inosculating branches. 65. Branch to the rectus capitis anticus major muscle. 66. Ex- ternal branch of the posterior division, going to the trachelo- mastoid and complexus muscles. 67. The internal branch of the posterior division, which sends branches, (68), to the com- plexus and biventer cervicis muscles, and passes beneath and within the complexus muscle, pierces the biventer, and becomes the occipitalis major nerve. (XV.)—Third cervical nerve. 69. Anterior division, from which the greater part of the occipitalis minor, (70), auricularis magnus, (71), and superficialis colli, (72), come. 73. The external branch of the posterior division, going to the scaleni muscles, divided. 74. The internal branch of the posterior division, which supplies branches to the complexus, biventer cervicis, semispinalis colli and multifidus spinse muscles, and goes beneath and within the complexus muscle, pierces the biventer, and sends a cutaneous branch to the neck. (XVI.)—Fourth cervical nerve. 77. Anterior division. 78. Princi- pal root of the phrenic nerve. 79. The external branch of the posterior division divided. 80. Internal branch of the posterior division. 81. Muscular branches. 82. Descending superficial cervical nerve. (XVII.—XIX.)—The fifth, sixth, and seventh cervical nerves. 83. The anterior divisions. 84. The external branches of the posterior divisions divided. 85. The internal branches of the posterior divisions. XX.—Superior cervical ganglion. 86. Inosculating branches with the first cervical, and 87, second cervical and hypoglossal nerves. 88. Sympathetic nerves accompanying the external carotid, 89, superior thyroid, 90, lingual, 91, facial, 92, occi- pital, and 93, internal maxillary arteries. 94. Trunk of the cervical sympathetic. 95. Middle cardiac nerve divided. PLATE VII. DESCRIPTION OF THE PLATES. XXXVII PLATE VII. THE NERVES OF THE TEMPORAL FOSSA, SUBCUTANEOUS MAL2E, DENTAL, DESCENDENS NONI, EXTERNAL, BRANCH OF THE SPINAL ACCESSORY, AND THE CERVICAL PLEXUS. This plate shows the right side of the head with the course of the subcutaneous make through the malar foramina, the distribution of the dental nerves to the superior and inferior maxillae, the relation between the nerves of the temporal fossa and the internal maxillary vessels, the course and inosculations of the descendens noni and ex- ternal branch of the spinal accessory, and the position and distribu- tion of the superficial cervical plexus. The right side of the skull, zygomatic arch with the temporal fascia, the ramus of the inferior maxilla, and the masseter, platysma, sterno- cleido-mastoid and trapezius muscles are removed; the muscles to- gether with the vessels and nerves of the face are in part cut away, and the malar and dental canals are opened to view. Hence, the dura mater and middle meningeal artery, the mucous membrane of the antrum of Highmore, the fangs of the teeth, and the muscles, vessels, and nerves of the temporal fossa and of the neck situated under the parts removed are seen. A. —Skin, divided in the median line from the nose and glabella to the neck. B. —Frontal bone. a. Coronal suture, b. Right frontal sinus. C. —Parietal bone. c. Lambdoid suture, d. The lower part of the right parietal bone. e. Its anterior inferior angle, f. Men- ingeal canal in the anterior inferior angle divided transversely. g. Meningeal grooves. I).—Tabular portion of the occipital bone. E. —Temporal bone. h. Glenoid fossa, i. Eminentia articularis. k. Root of the zygomatic process divided. F. —The malar bone, partly removed, to show the malar foramina. Gr.—Superior maxillary bone. I. Infraorbital foramen, m. Mucous membrane of the antrum of Highmore, n. Alveoli and fangs of the teeth. H.—Inferior maxillary bone. o. Angle of the inferior maxillary. XXXVIII DESCRIPTION OF THE PLATES. p. Dental foramen, q. Inferior dental canal, r. Mental foramen, s. Alveoli and fangs of the teeth. I.—The incisor, K, canine, L, bicuspid, and M, molar teeth. Jf.—Hyoid bone. O. —Occipital portion of the occipito-frontalis muscle. P. Retrahens aurem muscle. Q. —Temporal muscle, t. Its superficial, and u, deep portions. R. —The external, and S, internal pterygoid muscles. T.—Posterior part of the buccinator muscle. U. Mucous membrane of the gums. V.—Mylo-hyoid muscle. A.—Insertion of the sterno-cleido-mastoid muscle. E.—Splenius capitis muscle, of which a small part is removed, to show the course of the occipital artery, z. Splenius colli muscle. H. Upper part of the trachelo-mastoid muscle, seen beneath the splenius capitis. ®. Levator anguli scapulae muscle. I. Upper part of the biventer cervicis muscle. K. Scalenus medius, and A, scalenus anticus muscles. M. Ex- ternal margin of the rectus capitis anticus major muscle. N.—The thyroid gland. S. —The pinna, turned forward to show the distribution of the auricular nerves. o.—Common carotid. n.—Superior thyroid artery, y. Superior laryngeal artery, z. Thy- roid branches, a. Muscular branch. P. —Lingual artery, arising by a common trunk with the facial. 5.—Facial artery. 6. Submental artery, y. Trunk of the facial, divided transversely. T. —External carotid, passing between the inferior maxillary bone and temporal vein. T.—Occipital artery. J. Arteria princeps cervicis. e. Terminal branch. —Posterior auricular artery. £. Auricular branches. «. Occipital branch, divided transversely. X.—Internal maxillary artery. S. Inferior dental artery, i. Menin- geal branches of the middle meningeal artery. Its anterior larger branch passes through a canal in the anterior infe- rior angle of the parietal bone. x. Masseteric artery divided. X. Posterior deep temporal artery, pi. Buccal artery. DESCRIPTION OF THE PLATES. XXXIX v. Anterior deep temporal artery. Posterior dental artery, o. Infraorbital artery. —Temporal artery. The divided branches of the transverse facial artery are seen amongst the internal maxillary veins (t). tt. Middle temporal artery, which divides into two branches, ascending (p) and transverse («•). 12.—Internal carotid. AA.—Deep temporal plexus of veins. BB.—Temporal vein composed of two trunks which intercommuni- cate. The superficial trunk joins the facial vein and the deep trunk empties into the internal jugular vein. CC.—Pterygoid plexus, -r. Internal maxillary vein. u. Deep facial vein divided. DD.—Facial vein, divided near the inferior maxillary bone. EE.—Common trunk of the facial veins. <p. Superior thyroid vein. FF.—Internal jugular vein. GG.—Occipital vein. HH.—External surface of the dura mater. (V.)—Trifacial nerve. Second division. 1. Subcutaneous malae nerve. 2. Its temporal, and 3, zygomatic branches. 4. Infraorbital nerve. 5. Posterior dental nerves. 6. Buccal branch. 7. Dental branches. 8. Branches to the gums. 9. Inosculation of the anterior and posterior dental nerves. 10. Middle dental nerve. 11. Anterior dental nerve. 12. Dental branches, and 13, branches to the gums. 14. Branch to the nose. Third division. 15. Buccal nerve. 16. Its posterior buc- cal branches, and 17, anterior buccal branch divided. 18. Anterior deep temporal nerve. 19. Posterior deep temporal nerve. 20. Masseteric nerve divided. 21. Internal, and 22, external roots of the auriculo-temporal nerve. 23. Its trunk. 24. Branch of the auricular joining the facial. 25. Anterior auricular nerve divided. 26. Superficial temporal nerve. 27. Lingual nerve. 28. Inferior dental nerve. 29. Mylo-hyoid nerve. 30. Its muscular branches. 31. Dental branch. 32. Posterior inferior, and 33, anterior inferior dental nerve. 34. Branches to the mouth, 35, to the teeth, and 36, to the gums. 37. Mental branch divided. (VII.)—Facial nerve. 38. Posterior auricular’ nerve. 39. Branches to the retrahens aurem muscle. 40. Branch to the occipital portion of the occipito-frontalis muscle. 41. Cervico-facial XL DESCRIPTION OF THE PLATES. division of the facial nerve. 42. Temporo-facial division of the facial nerve, inosculating with the auriculo-temporal nerve. (XI.)—Spinal accessory nerve. 43. External division. 44. Branches to the sterno-cleido-mastoid muscle. 45. Branches to the trapezius muscle. 46. Branch inosculating with the third cervical nerve. (XII.)—Hypoglossal nerve. 47. Descendens noni branch. 48. De- scendens noni branches, uniting with branches of the third and fourth cervical nerves. 49. Ansa hypoglossi, sometimes on the jugular vein and sometimes between it and the com- mon carotid artery. 50. Branches to the sterno-hyoid, omo- hyoid, and sterno-thyroid muscles. 51. Curve of the hypo- glossal nerve. 52. Branch to the thyro-hyoid muscle. 53. Lingual branch. (XIII.)—Second cervical nerve. 54. Occipitalis major nerve, piercing the biventer cervicis muscle and ascending to the occiput. 55. Descending inosculating branch of the anterior division of the second cervical nerve. (XV.)—Third cervical nerve. 56. Anterior division. 57. Branch to rectus capitis anticus major muscle. 58. Branches of com- munication with the fourth cervical, 59, the spinal accessory, and 60, the descendens noni nerves. 61. The occipitalis minor nerve, divided into two branches, of which the ante- rior lesser one, (62), is cut out; the posterior greater one, (63), sends its filaments to the anterior region of the occiput. 64. Auricularis magnus and superficialis colli nerves divided. 65. Distribution of the auricularis magnus to the posterior surface of the pinna. 66. Branch to the splenius capitis et colli muscle. (XVI.)—Fourth cervical nerve. 67. Anterior division. 68. Branch to the rectus capitis anticus major muscle. 69. Ascending, and 70, descending inosculating branches. 71. Branches to the levator anguli scapulae and splenius colli muscles. 72. Supraclavicular branches. (XVII.)—Fifth cervical nerve. 73. Its anterior division. (XVIII.)—Trunk of the sympathetic in the neck, (74). PLATE VIII DESCRIPTION OF THE PLATES. XLI PLATE VIII. DISTRIBUTION OF THE NERVES OF THE FACE AND NECK UNDER THE SUBCUTANEOUS MUSCLES OF THE FACE, THE PLATYSMA, AND THE TRAPEZIUS. The right side of the head, with the exit and distribution of the first, second, and third divisions of the fifth nerve in the face, the course and ramifications of the facial nerve under the subcutaneous muscles of the face, and the course and distribution of the superficial cervical nerves under the platysma and trapezius muscles are seen. The skin and adipose tissue of the right side, occipito-frontalis aponeurosis, the pericranium and external table of the skull are re- moved by layers, the diploe being removed to the vitreous table on the anterior portion of the parietal bone ; the parotid gland is taken out piece-meal, the muscles of the face are partly, and the platysma and trapezius wholly removed. Therefore we see, firstly, the layers of the scalp and skull; sec- ondly, the muscles, vessels, and nerves found under the parotid gland and subcutaneous muscles of the face and neck, then the exit of the nerves from the cranium into the face, and finally the distri- bution of the nerves under the subcutaneous muscles. A. —Section of the skin and adipose tissue in the median line. B. —Aponeurosis of the occipito-frontalis muscle, likewise divided. C. —Pericranium. D. —The skull, a. The outer table, b. Diploe of the frontal bone. c. Frontal diploic veins, d. Diploe of the posterior part of the parietal and superior part of the occipital bones, e. Pa- rietal diploic veins, f. Coronal suture, g. Vitreous table of the anterior portion of the parietal bone, the inner sur- face of which is traversed by arterial grooves. _E.—Temporal fascia, covering the temporal muscle, h. The inner, and t, outer layers of the temporal fascia. The outer layer is removed at the position of the middle temporal vein, so that its course may be seen. k. Semilunar opening in the superficial layer, through which the middle temporal vein passes. I. Opening in the deep layer for the passage of the XLII DESCRIPTION OF THE PLATES. deep temporal vein. m. Malar foramina in the temporal fascia. F.—Eyelids. G .—Malar bone. n. External malar foramina, o. Zygomatic arch. H. —Superior maxillary bone. p. Infraorbital foramen. I. —Nasal bone. K. —Nasal cartilages : q, superior lateral, r, lower lateral, and s, sesamoid. L. —Inferior maxillary bone. t. Mental foramen, m. Ramus of the inferior maxillary bone. M. —Hyoid bone. N. —The pinna. O. —Origin of the zygomaticus major muscle. P.—Levator anguli oris muscle. Q.—Buccinator muscle. R.—Depressor an- guli oris, and S, depressor labii inferioris muscles divided near their origins. T.—Levator labii inferioris muscle. U.—Temporal muscle, divided transversely. V.—Masseter muscle. v. Its deep, and w, superficial portions. W. —Sterno-cleido-mastoid muscle. X. —Trapezius muscle, divided near its origin. Y.—Splenitis capitis et colli muscle. Z.— Levator anguli scapulae muscle. A.—Biventer cervicis muscle. B.—Sterno-hyoid muscle. r.— Superior belly of the omo-hyoid muscle. A.— Superior extremity of the sterno-thyroid muscle. E.—Thyro-hyoid muscle. z.—Insertion of the stylo-hyoid muscle. H.—Digastric muscle. x. Its anterior belly, y. Central tendon, z. Suprahyoid aponeurosis. 0.—Superior thyroid artery. I.—Facial artery, a. Muscular branch. 0. Mental branches, y. Buccal branches. . J. Anastomosis of a buccal branch with the transverse facial artery, e. Inferior, and £, superior coronary arteries. «. Anastomosis with the infraorbital artery. S. Artery of the nasal septum, i. Lateralis nasi artery, x. Branch anastomosing with the ophthalmic artery. K.—Ophthalmic artery. A. Frontal artery. Nasal artery, v. Su- praorbital artery. A.—Temporal artery, partly covered by the trunk of the temporal vein. £. Transverse facial artery. DESCRIPTION OF THE PLATES. XLIII M. —Internal maxillary artery, o. Buccal artery, w. Mental artery. p. Infraorbital artery, a. Superficial perforating branch of the anterior deep temporal artery. N. —Posterior auricular artery. H.—Occipital artery. O. —Facial vein. A great portion of the trunk of this vein is removed, so that the exit of the infraorbital nerve may be seen. t. Frontal vein. v. Supraorbital vein. <p. Dorsalis nasi vein. Anterior extremity of the ophthalmic vein. V. Lat- eralis nasi vein. a>. Deep facial vein. aa. Infralabial vein. bb. Submental vein. n.—Temporal vein, which is sometimes double, cc. Superficial tem- poral vein. del. Middle temporal vein, which anastomoses with the supraorbital, (ee), subcutaneous temporal, (ff'), and deep temporal, (yy), veins, hh. Auricular veins, ii. Mus- cular veins, kk. Internal maxillary vein. P. —Trunk of the external jugular vein. 2.—Superficial cervical vein. II. Occipital vein. mm. Anastomosing branch with the deep cervical plexus. nn. Cervical branches. T.—Submaxillary gland. (V.)—Trifacial nerve. First division.. 1. Frontal branches of the supraorbital nerve, at times passing over and at times under the supraorbital vein. Many branches issue between the frontal notch and the superior palpebral aponeurosis, only one issues through the frontal foramen from the orbit. 2. Superior palpebral branch of the frontal nerve coming through a foramen of the aponeurosis, and 3, the supratrochlear nerve coming through another. 4. Frontal, and 5, superior palpebral branches of the supratrochlear nerve. 6. Infratrochlear nerve. 7. Ex- ternal branch of the nasal nerve. Second division. 8. Subcutaneous branches of the temporo-malar nerve, coming through openings in the temporal fascia. 9. Their junction with the facial nerve. 10. Zygomatic branches of the subcutaneous malae nerve divided. 11. In- fraorbital nerve. 12. Inferior palpebral branches. 13. Junc- tion with the facial nerve. 14. Superior, and 15, inferior lateral nasal branches. 16. Internal, and 17, external supe- XLIV DESCRIPTION OF THE PLATES rior labial branches. 18. Buccal branches. 19. Junction with the facial nerve. Third division. 20. Mental nerve. 21. Mental branches. 22. In- ternal, and 23, external inferior labial branches. 24. Buccal branches. 25. Junction with the facial nerve. 26. The anterior buccal branches of the buccal nerve. 27. Their junction with the facial nerve. 28. Branches of the auriculo- temporal, communicating with the facial nerve. 29. Super- ficial temporal branch of the auriculo-temporal nerve. VII.—Trunk of the facial, seen in the infraauricular fossa. 30. Temporo-facial division of the facial nerve. 31. Temporal, 32, malar, and 33, superior buccal branches. 34. Cer- vico-facial division of the facial nerve. 35. Inferior buccal branches. 36. Supramaxillary branch. 37. Inframaxillary branch. 38. Its inosculation with the superficialis colli. 39. Intercommunication of the branches of the facial, forming the pes anserinus. Many branches of the facial nerve are cut through near the muscles of the face, which are re- moved. (XI.)—Spinal accessory nerve. 40. Its external division, going to the trapezius muscle. (XIV.)—Second cervical nerve. 41. Occipitalis major nerve, piercing the biventer cervicis muscle. 42. Cervical cutaneous branch divided. 43. Occipital branches. (XV.)—Third cervical nerve. 44. Occipitalis minor. 45. Auricularis magnus nerve. 46. Its facial branch divided, and 47, its auricular branch. 48. The middle, and 49, inferior branches of the superficialis colli. 50. Cutaneous branches divided. 51. Branches going to the levator anguli scapulae muscle. 52. Junction with the fourth cervical nerve. (XVI.)—Fourth cervical nerve. 53. Supraclavicular branches. 54. Phrenic nerve. PLATE IX. XLV DESCRIPTION OF THE PLATES. PLATE IX. COURSE OF THE SUBCUTANEOUS CRANIAL NERVES. THE SUPERFICIAL DISTRIBUTION OF THE FACIAL, FIRST, SECOND, AND THIRD DIVISIONS OF THE TRIFACIAL, AND THE SUBCUTANEOUS RAMIFICATIONS OF THE SECOND, THIRD, AND FOURTH CERVICAL NERVES ON THE RIGHT SIDE OF THE HEAD. The skin of the right side of the head and neck is removed, bring- ing the subjacent parts into view. Therefore the parotid gland, Stenson’s duct, and the subcutaneous muscles, vessels, and nerves of the head, face, and neck may be seen. A. —Skin and adipose tissue divided in the median line. B. —Pinna, with the helix turned forward to show the retrahens aurem muscle and posterior auricular nerve. C. —Epicranial muscle, a. Its occipital portion, b, aponeurosis, and c, frontal portion. I).—Attolens aurem muscle. E. —Retrahens aurem muscle. F. —Orbicularis palpebrarum muscle, d. Its orbital, and e, palpe- bral portions. Gr.—Pyramidalis nasi muscle. H. Compressor nasi muscle. I. Levator labii superioris alaeque nasi muscle, f. Its nasal, and <7, labial portions. K.—Levator labii superioris proprius, L, levator anguli oris, M, zygomaticus major, N, zygomaticus minor, O, buccinator, P, risorius, Q, depressor anguli oris, K, depressor labii in- ferioris, S, orbicularis oris, and T, levator labii inferiors muscles. U. —Masseter muscle, h. Its superficial, and i, deep portions. V. —Platysma muscle. W. Sterno-cleido-mastoid muscle, k. Its superior tendinous extremity. X.—Trapezius, and Y, splenius capitis et colli muscles. Z. Leva- tor anguli scapulae muscle. A.—Parotid gland. I. Stenson’s duct. m. Accessory parotid gland. XLVI DESCRIPTION OF THE PLATES. B.—Facial artery, n. Masseteric branch anastomosing with a branch of the transverse facial artery. o. Buccal branch, also anastomosing with a branch of the transverse facial artery. • p. Artery of the nasal septum, q. Lateralis nasi artery. r. Dorsalis nasi artery, s. Angular artery, t. Anastomosis with the ophthalmic artery. r.—Temporal artery, u. Superior, and v, inferior branches of the transverse facial artery. w. Zygomatico-orbital artery. x. Anastomosing branch with the transverse facial artery. y. Anterior, and z, posterior superficial temporal arteries, a. Anastomoses with the supraorbital, and B, occipital arteries. A. Posterior auricular artery, y. Auricular branches. J. Occipital branch. E. Occipital artery, e. Terminal occipital branch. Z. Ophthalmic artery. £. Supraorbital artery, passing through the frontal muscle and then ascending upon it. n. Dorsalis nasi artery. A. Branch anastomosing with the facial artery. H. Facial vein. i. Frontal vein. x. Dorsalis nasi vein. x. Branch of the supraorbital vein, perforating the orbicularis palpe- brarum muscle and anastomosing with the facial vein. ®. Temporal vein. pt,. Superficial temporal vein. v. Its anterior, and £, posterior branches, o. Anastomoses with the frontal, 7r, supraorbital, and p, occipital veins. <r. Middle temporal vein. t. The trunk of the temporal vein is here double, but usually only one trunk is found. I. External jugular vein, covered by the platysma muscle. K. Superficial cervical vein. v. Occipital vein. <f>. Anastomosing branch with the deep cervical plexus, Cervical branches. (V.)—Trifacial nerve. First division. 1. Frontal branches of the frontal nerve, passing through the fibres of the frontal muscle, then going to the vertex subcutaneously. 2. Frontal branches of the supratrochlear nerve. Second division. 3. Inferior palpebral branch of the infraorbital nerve. 4. Laterales nasi branches of the infraorbital nerve. Third division. 5. Anterior auricular branch, and 6, temporal branches of the auriculo-temporal nerve. 7. The anterior buccal branches of the buccal nerve. 8. Branches of the buccal joining the facial nerve. DESCRIPTION OF THE PLATES. XLVII (.VII.)—Facial nerve. 9. Posterior auricular nerve. 10. Temporal, 11, malar, 12, superior buccal, and 13, inferior buccal branches 14. Supramaxillary, and 15, inframaxillary branches. 16. Branch piercing the platysma muscle. 17. Inosculation with the middle superficialis colli nerve. 18. Intercommunicating branches of the facial nerve (XI.)—Spinal accessory nerve. 19 Its external division, going to the trapezius muscle. (XIV.)—Second cervical nerve. 20. Occipitalis major nerve, piercing the biventer cervicis and part of the trapezius muscles. Branches of this nerve accompany the occipital artery and vein to the vertex. (XV.)—Third cervical nerve. 21. Occipitalis minor, one branch of which pierces the border of the trapezius muscle and ascends to the anterior part of the occiput; another branch passes amongst the branches of the superficial cervical vein, joins the occipitalis major nerve and goes to the vertex. 22. An- terior cervical cutaneous branches. 23. Auricularis magnus nerve. 24. Its auricular branches. 25. Facial branch of the auricularis magnus. 26. Facial cutaneous branches divided. 27. Cutaneous branches piercing the platysma muscle. 28. Superficialis colli nerves piercing the platysma muscle. 29. Branches to the levator anguli scapulae muscle. (XVI.)—Fourth cervical nerve. 30. Its anterior division. ESSENTIALS OF HUMAN PHYSIOLOGY. What is physiology? Physiology is the study of vital phenomena which are always present in living things be they animal or vegetable. As a con- sequence of this we divide physiology into two subdivisions, known as animal physiology and vegetable physiology, but it should be remembered that the line of demarcation between animals and vegetables in the lower forms of life is very ill-defined. The word physiology is derived from the Greek word nature, and Xoyo?, a discourse, and in its original meaning was applied to the study of natural history in general. Physiology is really synonymous with the term biology, since it is necessary for the study of either one that vital properties be present in the thing studied. The term biology, however, has a wider scope with certain persons, as under some circumstances it is divided up into morphology, which treats of the forms and structure of living bodies, while physiology at- tempts to explain the modes of activity exhibited by them during their lifetime. In other words, morphology stands in the same position in reference to physiology as does anatomy. The term vital phenomena is applied to the changes which constantly go on in all living bodies, the primary causes of which are not at all understood; in other words, while we note the ultimate object of each function we can give no cause for the setting in motion of that function. What is the chemical basis of the body? Of the sixty-nine elements known to chemists, a very small number, comparatively speaking, are found in any quantity in living animal matter, although traces of them are frequently present. Oxygen, carbon, hydrogen, and nitrogen are present in very large proportions in every tissue, and together make up about 97 per cent, of the whole body, while the sulphur, phosphorus, chlorine, fluorine, silica, potassium, sodium, magnesium, calcium, 18 ESSENTIALS OF HUMAN PHYSIOLOGY. and iron are indispensable to the economy, but are widely distrib- uted and occur in much smaller quantities. Since to investigate the chemical composition of a tissue must require analysis, the composition of the tissues during life is, strictly speaking, un- known, since by the very analysis death is produced. An im- portant point to be remembered is that all animal bodies, be they simple or complex, are made up of protoplasm more or less differ- entiated according to the function which it is to fulfil. What two great groups of substances make up the body ? Physiological chemistry teaches us that we have in the body two sets or groups of substances known as nitrogenous and non-nitro- genous. The nitrogenous perform the most important functions, and, indeed, form all the active portions of the organism. As the simplest representative of these nitrogenous bodies may be men- tioned protoplasm itself. Derived from this and entering into the formation of it are albumens, serum-albumens, and, thirdly, by the outcome of still further differentiation we have albuminoids, chiefly represented by gelatine. Last of all are those products which, though nitrogenous, differ from the others in that they are intermediate or effete products of tissue manufacture or waste, as, for example, urea, uric acid, kreatin, and kreatinin. The non- nitrogenous substances consist chiefly of the carbohydrates, which contain hydrogen and oxygen in the proportion found in water, as, for example, starch and sugar. Then we have substances contain- ing oxygen in less proportion than the above, namely, fats. Salts occur all through the tissue, as does also water. PROTEIDS. All compounds included in the group of proteids contain carbon, hydrogen, nitrogen, oxygen, and sulphur. They are amorphous, with variable solubility in water and acids, usually soluble in alkalies, almost insoluble in alcohol and ether. They are precipitated from their solutions by excess of strong mineral acids, by acetic or hydrochloric acid, potassium ferro- cyanide, and the basic acetate of lead, mercury bichloride, tannin, and potassium carbonate in powder. CLASSIFICATION OF PROTEIDS. 19 The following table, taken from Gamgee’s Physiological Chem- istry, is of great importance, and gives the points to be remembered most tersely. This will be, of necessity, frequently referred to later on. Class 1.—Albumens are proteid bodies which are soluble in water, and which are not precipitated by alkaline carbonates, by sodium chlo- ride, or by very dilute acids. If dried at a temperature below 40° C. they become transparent and yellow, break with vitreous frac- ture, and are soluble in water. Coagulation occurs between 65° and 73° C. 1. Serum-albumen, not precipitated from its solutions by the addition of ether. 2. Egg-albumen, precipitated from its solution by agitation with ether. Class 2.—Peptones, proteid bodies exceedingly soluble in water. Solu- tions are not coagulated by heat when precipitated by sodium chlo- ride, nor by acids or alkalies ; precipitated by a large excess of absolute alkali and by tannic acid in the presence of much caustic potash or soda. A trace of a solution of copper sulphate produces a beautiful rose color. Soluble in pure water Class 3.—Globulins, proteid substances which are insoluble in pure water but soluble in dilute solutions of NaCI. These solutions are coagulated by heat They are soluble in dilute hydrochloric acid, being converted by alkalies into alkali-albumen. 1. Vitellin, not precipitated from its solution when saturated with common salt. 2. Myosin, precipitated from its solution by weak common salt. When saturated with sodium chloride it coagulates at 55° to 60° C. Solutions in common salt are not coagu- lated by a solution of fibrin-ferment. 3. Fibrinogen, soluble in weak solutions of NaCI, precipitated from them completely on the addition of NaCI when this amounts to twelve or sixteen percent. Solutions coagulate on the addition of fibrin-ferment and at the temperature of 60? C. 4. Paraglobulin, soluble in weak solutions of NaCI, and pre- cipitated from weak alkaline solutions by the addition of a small quantity of NaCI. A further addition of this body redissolves the precipitate, which is again precipitated, although not so completely as before. When the amount of NaCI in solution exceeds twenty per cent, paraglobulin is completely precipitated when the solution is saturated with ammonium sulphate. Its solutions are not precipitated by the addition of the fibrin ferment It coagulates at different temperatures according to the amount of salts present and the mode of heating, but generally between 68° and 80° C. Insoluble in pure water, but soluble in weak solutions of common salt 20 ESSENTIALS OF HUMAN PHYSIOLOGY. Class 4.—Derived albumens, proteid bodies insoluble in pure water and in solution? of NaCl, but readily soluble in dilute HC1 and iv. dilute alkaline solutions. Solutions are not coagulated by heat. 1. Acid-albumens, obtained by the action of dilute acids, especially HC1, on solutions of proteids, and by action of strong acids upon solid proteids. They occur as first products in the action of gastric juice. NaCl added to saturation precipitates them. 2. (a) Alkali-albumens, obtained by the action of dilute alkalies upon the pro- teids, possessing the properties of acid-albumen with the exception that in the presence of an alkaline phosphate the solutions are not precipitated by neutralization. They occur as the first products of pancreatic digestion (6) Casein, the chief proteid constituent of milk, has the same properties as alkali-albumen, but when treated with a strong solution of caustic potash potassium sulphide is formed ; with alkali-albumen it is not formed. Class 5.—Fibrin is insoluble in water and in weak solutions of NaCl, and becomes swelled up in cold hydrochloric acid of one-tenth per cent, solution, but does not dissolve unless pepsin is added and heat is applied. 1. What tests have we for proteids? The nitric acid test, which consists in heating the liquid and adding nitric acid until the reaction is strongly acid, when a pre- cipitate occurs. Remember, that this is not an infallible test for all proteids, as, for example, the peptones, which will not respond to it. 2. What is the xantho-proteic reaction? Heat with concentrated nitric acid, when, if a proteid be present, a yellow tint appears, which becomes reddish-'orange on the addition of alkalies. 3. What is Millon’s reagent? It is made by dissolving in the cold one part of mercury in its weight of concentrated nitric acid, the solution being completed by applying gentle warmth; two volumes of distilled water are then added, and the fluid decanted. This test gives a red color with liquids containing proteids, which is more marked when they are heated to 60° C. or 70° C. CARBO-HYDRATES. These include the starches and sugars. What test have we for starch ? Starch, when added to free iodine, strikes a blue color which dis- appears on the application of heat, but returns if the liquid be THE BLOOD. 21 suddenly cooled. If heated to the temperature of 210° C. starch is converted into dextrin, and, as we shall learn later, the digestive fluids change starch into glucose or grape sugar. Sugars are substances having a more or less sweet taste, usually soluble in water, destroyed by strong H2SO4, which abstracts water from these compounds, and leaves only the carbon. The most important of this group are glucose, lactose, saccharose, and gly- cogen. On fermentation they yield CO2 and alcohol. What test have we for sugars ? Trommels test, which depends upon the fact that sugar in an alkaline solution acts as a reducing agent. To the saccharine fluid about one-fourth of its bulk of caustic potash or soda is added, and a dilute solution of copper sulphate. A slight clouding occurs which disappears on shaking, but boiling strikes a brick-red color. Fats are widely distributed in plants and in animals. They contain very little oxygen, and are soluble in ether, benzole, chloro- form, and in boiling alcohol. When fats are boiled with solutions of the alkaline hydrates or carbonates they undergo saponification, and are decomposed into glycerin and fatty acids. The latter immediately combine with the alkali and form soap. Fats also undergo emulsification, in which process they are broken up into a condition of extremely fine subdivision. THE BLOOD. What is the function of the blood ? In all animals, except those which form the lowest class, a liquid medium corresponding, in function at least, to the blood of man, circulates. It serves in the distribution of nutritious materials to the various parts of the system and, equally important, it collects those substances which have resulted from the changes which are constantly going on in the tissues and bears them to those organs whose function it is to discharge them from the body. Quite as important is the constant intercourse which it keeps up between the tissues and the air, supplying them with oxygen. 22 ESSENTIALS OF HUMAN PHYSIOLOGY. What is the color of the blood in the different portions of the circulatory system ? The color of the blood as it occurs in the systemic arteries is of a bright scarlet-red, while in the corresponding veins it is of a dark bluish color. In the pulmonary artery it is dark blue, in the pulmonary veins scarlet. What is the cause of this variation ? The cause of this variation is due to the oxygen of the air, which, entering into a chemical combination with the haemoglobin of the red blood corpuscles, produces oxyhaemoglobin, which gives up some of its oxygen to the tissues of the body as it passes through the capillaries, and returns in the veins partly decomposed into .re- duced haemoglobin, which gives to the venous blood its dark hue. Is the entire amount of oxyhaemoglobin reduced in venous blood ? No. The reduction of haemoglobin amounts to only about five per cent. Are the red blood corpuscles red or yellow ? They are red, for their coloring matter, haemoglobin, is red when isolated and crystallized. The color of the red corpuscles when seen singly is yellowish-red. The difference in color between those seen enmaw and those seen singly is due to the refraction of light. What is the reaction of the blood ? The reaction is alkaline, owing to the presence of sodium carbo- nate and disodic phosphate, Na2HPO4. Does it always retain its alkalinity ? Always during life, but after blood is shed its alkalinity rapidly diminishes, and the greater the alkalinity of the blood is, the more rapidly this change occurs. Finally, the reaction becomes strongly acid, this change coming at about the time of coagula- tion. What is the odor of the blood ? The odor which the blood possesses differs in the various animals, and in some, animals is very characteristic. This odor depends upon the presence of volatile fatty acids. THE BLOOD. 23 What is the taste ? It is saline in taste, which is dependent upon the salts contained in it. What is the specific gravity of the blood ? The specific gravity is 1055, the extreme limits being from 1045 to 1075. The specific gravity of the blood corpuscles alone is 1105, that of the plasma 1027. As a consequence of this, blood corpuscles tend to sink to the bottom of the receptacle into which the blood is drawn. What is the temperature of the blood ? It varies from 98° F. at the surface of the body to 107° in the hepatic vein. Of what does the blood consist ? Blood, when flowing in a normal condition through the blood- vessels, consists of an almost colorless fluid, the plasma, in which are suspended small solid bodies, known as red and white blood corpuscles and blood-plates. The liquid portion of the blood (the blood plasma or liquor sanguinis) is of a pale straw color when free from blood corpuscles or other coloring matter, and is the liquid which keeps the corpuscles afloat. The blood plasma is not identical with the serum of the blood, since radical changes take place in its composition during coagulation, and the serum results after the clot is formed. Serum will not of itself form a clot, plasma will; in other words, one of the differences between liquor sanguinis, or plasma, and serum, is that the first contains fibrino- gen, while the second does not. Is there any variation in the character of the blood in different parts of the circulatory system ? The arterial blood contains more oxygen and less CO2, and is more coagulable. The blood of the portal vein varies with the stages of digestion, during which time it is richer in water, albu- minous matters, and sugars, with a diminished number of cor- puscles. In the hepatic vein the sugar is increased, but the albumin and fibrinogen diminished. 24 ESSENTIALS OF HUMAN PHYSIOLOGY. What are the two varieties of blood corpuscles ? Red and white. What others have we ? Very small ones, known as microcytes, and the so-called blood- plates. What is the function of these microcytes ? Most physiologists believe them to be young red blood corpuscles, others that they are worn-out red blood corpuscles. What is the function of the blood-plates ? It is not known, but they are found in large numbers in thrombi, and possibly take part in the process of coagulation by helping to form fibrin-ferment. They do not become red corpuscles. Describe the white corpuscles. They are small protoplasmic cells, differing in no way from the pale round cells found in most portions of the body, and occur in large quantities in the lymph. For this reason they are sometimes called lymphoid cells or leucocytes. They possess a finely granular structure and nuclei, and these nuclei may often be recognized near the centre of the cell. The nuclei may be made more marked by the action of certain reagents, notably acetic acid. They pos- sess an amoeboid movement, and so are enabled to migrate not only through the bloodvessel wall, but also through the tissues. They are somewhat larger than the red disks, and do not possess a cell wall. What do you mean by diapedesis ? The passage of the white blood corpuscles through the blood- vessel wall. The white corpuscles constantly pass through normally, but in very large numbers in inflammation. The red only under morbid conditions, as in injury or inflammation. What are the relative positions of the red and white cor- puscles in the blood stream of the smaller arterioles and capillaries ? The red move along rapidly in the centre, while the white slowly roll along the walls. If inflammation occurs, they stop and block THE BLOOD. 25 the vessel. The layer of blood in which the white corpuscles lie is called the “ still layer.” Where are the white corpuscles formed ? According to the best physiologists, in the lymphatic glands and the spleen, and very similar cells develop in the connective tissues through multiplication by division. What are their functions ? 1. To destroy pathogenic bacteria (the phagocytosis theory of Metschnikoff). 2. To take part in the process of blood-coagulation by forming fibrin-ferment (thrombin). 3. To aid by their disintegration the normal composition of the blood-plasma as to proteids. Describe the red blood corpuscles. The red blood corpuscles give the red color to the blood of all vertebrated animals except the amphioxus, but are not found in the blood of invertebrates. They differ in their shape in almost all animals, in the mammalia they are biconcave disks. Their size differs in each class of animals, but the size of the animal has no relation to the size of the corpuscle, for in the frog all the corpuscular elements are of great size. They are soft and elastic, and bend and alter their shape when necessary to pass through a narrow bloodvessel, but return immediately to their normal shape as soon as the pressure is removed. If blood be withdrawn from the body, even for a few moments, and then returned to the circu- lation, death of the corpuscles takes place, and in a short time evidences of their destruction may be noticed by the presence of haemoglobin in the urine. What is one of the peculiarities of the red blood corpuscles outside the body ? They form themselves into rouleaux, which resemble very closely the appearance of a large number of coins placed side by side. This peculiarity is due rather to a physical law than to any action of the corpuscles themselves, since it has been found that small disks of cork will do very much the same thing when placed in water. 26 ESSENTIALS OF HUMAN PHYSIOLOGY. Have the red blood corpuscles any nuclei ? Not in adult life, but owing to their biconcave shape the refrac- tion is such that under the microscope a dark spot is apparently situated near their centre. In the young embryo nucleated red corpuscles are found. Are the red blood corpuscles few, or are they exceedingly great in number ? Their quantity is enormous; a cubic millimetre contains be- tween four and five millions. Approximate mathematical estimates show that the red blood corpuscles of an adult present an aggre- gate surface of about three thousand square yards, while the surface they represent for the absorption of oxygen in the lungs in one second is about eighty square yards. How are they formed ? In adult life from the erythroblasts of the red marrow of the bones; in the embryo they are also formed in the liver and spleen. What is the end of the life history of the red blood cor- puscles ? Many physiologists regard the liver as one of the chief places where the disintegration of the red blood corpuscles takes place, and this is supported by the facts that the bile-pigments are formed from haemoglobin and that the blood of the hepatic vein contains fewer red blood corpuscles than the blood of the portal vein. The spleen is also regarded as one of the organs in which the red blood corpuscle is disintegrated. It is probable that they are destroyed largely while in the general circulation, and do not require any special organ for their destruction. What are the functions of the red corpuscles, and their rela- tive number to the white corpuscles ? The function of the red blood corpuscles is entirely different from that of the white blood corpuscles. The red blood corpuscle contains in its stroma a large amount of haemoglobin which, when exposed to the air in the lung, takes up oxygen, thereby forming the chemical compound known as oxy-haemoglobin. By these means the tissues, even in the most distantly removed parts of the THE BLOOD. 27 body from the lung, receive their oxygen, the exchange of oxygen from the corpuscles to the tissues taking place in the capillaries. By this means, oxidation, with the resulting tissue break-down, and the development of heat, takes place in every portion of the body. The relative number of the white blood corpuscles to the red has been much discussed, some observers giving it as 1 to 300, while others state that it is 1 to 700. The proportion varies so much in different parts of the circulation that no estimate is of any great value. ! Do changes ever occur in the relative number of red and white corpuscles in health? Very frequently, since many circumstances arising in every- day life may produce great changes in this respect. The varia- tion may be all the way from 1 in 50 to 1 in 1200. Pregnancy decreases the proportion; meals also have a very powerful effect on their relative numbers. Certain diseases also alter the pro- portion greatly. What is haemoglobin ? It is the substance which gives the red color to the corpuscles, and carries by their aid the oxygen to the tissues. What is haematin ? A result of the decomposition of haemoglobin by acids or alka- lies in the presence of oxygen. Haemin is a compound of haematin and HC1. Haematoidin is a crystallizable substance found in old blood- clots and comes from haemoglobin. It is identical with the bile- pigment, bilirubin. What are the gases of the blood ? Chiefly oxygen, carbonic acid, and nitrogen. The oxygen exists, as before stated, in chemical combination with the haemoglobin, and is also in small amounts simply absorbed by the blood plasma. Carbonic acid occurs in less amount in arterial blood than in venous blood. Nitrogen exists in the blood in very small amount, and appears to be simply absorbed. 28 ESSENTIALS OF HUMAN PHYSIOLOGY. From 100 volumes of blood may be obtained— o. co2. N. Of arterial blood (from a large artery), 20 vols. . . 40 vols. . . 1 to 2 vols. Of venous blood (from right side of heart), 8-12 “ . . 46 “ . . 1 to 2 “ Does C02 unite with the haemoglobin? No. It is held in solution chiefly by the plasma, and in very small amount in the red blood corpuscles. What is the quantity of the blood ? The quantity of blood in a human male adult is equal to one- thirteenth part of the body weight. Coagulation of Blood. Blood, on being withdrawn from a vessel, is perfectly fluid, but rapidly becomes thick, and then forms a clot resembling a solid gelatinous mass. What is this clotting due to ? The formation of fibrin, in part at least, from fibrinogen. Does fibrin exist already formed in the blood ? No. llow is it produced? There is no perfectly satisfactory theory of coagulation. The most generally accepted one is that of Hammarsten, that the reac- tion between fibrinogen and fibrin-ferment (thrombin) produces fibrin. It is also necessary that calcium salts be present, for without them fibrin cannot be formed from fibrinogen. Fibrin-ferment does not exist in the blood until after it is shed; then the disinte- gration of the white blood corpuscles occurs and the ferment is formed. How is the clot made up ? The fibrin forms in fibrils, which entangle the blood corpuscles as in a spider’s web, and thereby form a complete blood-clot. COAGULATION OF BLOOD. 29 The blood in the body is made up as follows : Blood l Plasma Corpuscles (red and white) I Water I Salts l Fibrin-ferment I Serum-albumin I Paraglobulin I Fibrinogen. Blood when it has undergone coagulation is as follows: Blood I Plasma I „ , I Corpuscles, red and white Serum Fibrin I Clot I Containing fibrin, corpuscles, and serum. What changes take place after the clot is formed? The clot leaves the sides of the vessel, and on its surface there appear small transparent drops of yellowish liquid known as serum. These drops running together form a layer of yellowish fluid. In what way is the serum expelled from the clot? The fine fibrils of fibrin ramifying all through the clot contract, and squeeze out the serum. These fibrils also entangle the corpuscles. How long does this contraction and displacement of the serum last? From twenty-foui to thirty-six hours. How is blood defibrinated? By beating it with twigs or a glass rod. The fibrin adheres in sticky masses to the rods, and the remaining fluid will not clot. The corpuscles are left, most of them in the serum. 30 ESSENTIALS OF HUMAN PHYSIOLOGY. What conditions hinder or delay coagulation? The addition of small quantities of alkalies or of concentrated solutions of neutral salts of alkalies, notably magnesic sulphate; the addition of egg-albumin, syrup, glycerine, and much water; and by covering the blood with oil, or by cold at freezing point. What hastens coagulation ? Coagulation is accelerated by contact with any foreign body, by heating from 39° to 55° C., and by constant agitation. do you mean by the huffy coat? In blood which is drawn from a body during inflammation the fibrin coagulates slowly, and the corpuscles subside to the bottom of the vessel, so that the upper stratum of the clot is not red but only yellowish, containing scarcely any red blood corpuscles. This occurs physiologically in horses’ blood. What prevents coagulation of the blood in the bloodvessels? This is not positively known ; some relationship exists between living tissues and the blood. funder what circumstances does clotting in the bloodvessels occur ? As soon as the endothelial layer of the bloodvessels is in any way injured. How long after death does the blood coagulate in the body ? From ten to twenty-four hours. Do pathological changes ever take place in the blood ? Yes. Plethora is an increase in the quantity and quality of the blood, the red corpuscular elements being greatly increased in number ' Anaemia is a decrease in the corpuscular elements of the blood, without necessarily any increase in the liquids. Leucocythaemia or leukaemia is a term applied to a condition in which, together with other changes, the white blood corpuscles are very much increased in number, from 10,000 to 1,000,000 in a cubic millimetre of blood. In some cases the white corpuscles are as numerous as the red. THE HEART. 31 Urcemia cannot be considered a disease of the blood, but simply an accumulation of urea in that fluid, owing to kidney disorders. THE HEART. What is the simplest form of heart ? The early embryonic heart, which is merely a tubular heart with one cavity and an outer circular and inner longitudinal layer of fibres. Does the muscular fibre of this tubular heart afford walls to both the auricle and ventricle after the septum is formed ? Yes, but the muscular fibres of the auricle do not change to any extent, while the ventricular fibres become much altered. What separates the auricular fibres at this time from the ventricular fibres ? Fibro-cartilaginous rings at the opening in the septum. What is the function of the heart ? To propel blood through the body. How many cavities has it ? Four. What is the weight of the adult male heart ? Nine ounces. What is the weight of the adult left ventricle as compared to the right ? About twice as heavy. What is the difference between the right and left side of the heart ? The right side of the heart takes the venous blood from the vena cavae and pumps it through the lungs to the left side of the heart. This circulation is much more limited, of course, than that produced by the left side, and is known as the pulmonic circulation. 32 ESSENTIALS OF HUMAN PHYSIOLOGY. The left side of the heart receives the arterialized blood from the lung and drives it into the general arteries. This is known as the systemic circulation. Which is the strongest, the right or left side of the heart ? The left side is not only much stronger, but its walls are much thicker on account of the greater amount of work which it is forced to perform. What is the difference between the contraction of the auricles and the contraction of the ventricles ? The contraction of the ventricles takes place synchronously from all sides, so that the pressure within is equal in any direc- tion. The auricles contract peristaltically from the opening of the supplying vessel toward the auriculo-ventricular orifice. Which have the thickest walls, the ventricles or the auricles ? The ventricles, owing to the greater force which they are re- quired to put out. What is the function of the auricles ? To act as a reservoir for the blood while the ventricles are contracting, and force the blood through the auriculo-ventricular openings, and so supply the ventricles. Has the heart any suction power enabling it to aid the circulation not only by pushing but by sucking ? According to the latest researches it has not.1 *' What is the endocardium ? The membrane lining the heart. Is it limited to this viscus or not ? It is continuous with the endothelial lining of the bloodvessels. Has the endocardium bloodvessels No, it has not. 1 The muscular arrangement of the heart is probably already known to the student; if not, he must turn to his anatomical text-books. THE HEART. 33 /What are the valves of the heart ? They are fibrous flaps arranged in one of two ways, which open and shut the orifices which they guard. The edges of the auriculo- ventricular valves are attached by what are known as chordae tendineae to the walls of the ventricles. In what way are the valves attached to the heart ? They are fixed to the fibrous rings, made up of yellow elastic tissue and fibrous tissue which surround the openings. Do the valves have any muscular fibres in them ? According to Reid and Gussenbauer, the auriculo-ventricular valves do; the fibres come from the auricles. Have the valves bloodvessels ? None near the edges. Only as far as the muscular fibres run. What is the function of the valves ? To prevent the regurgitation of blood from a heart cavity, or bloodvessel, back into the area from which it has been propelled. What two sets of valves have we ? The auriculo-ventricular and semilunar. Where are they situated ? The semilunars guard the opening of the aorta and pulmonary artery. At the right auriculo-ventricular orifice we have the tricuspid valve, at the left auriculo-ventricular we have the mitral or bicuspid valve. How many cusps make up the semilunars ? Three at each opening. \Are there any valves at the opening of the cavae into the A right auricle ? No. Why are they not needed ? Because the peristaltic action of the auricle prevents a tendency to regurgitation, except in rare conditions. For the same reason 34 ESSENTIALS OF HUMAN PHYSIOLOGY. we have no valve at the opening of the pulmonary vein into the left auricle. jWhat are the chordae tendineae ? The chordae tendineae are small bands running from the mus- cular fibres of the heart wall to the edges of the valves. What is the function of the chordae tendineae ? To prevent the everting of the auriculo-ventricular valves into the auricles by a sudden pressure of blood during ventricular systole. < In what way is the heart nourished ? By means of its coronary arteries, which are peculiar in that they do not anastomose. Where do these arteries arise ? From the aorta near the sinus of Valsalva. What is the condition of the openings of these arteries during the period of systole ? They are closed by the aortic valves. <Are the veins of the heart called coronary veins ? No. They are called cardiac veins. What other cause produces an onward flow of the blood through the coronary arteries than the vis a tergo from the systolic driving out of blood into the aorta ? The lateral pressure exercised on the vessels by the surrounding heart muscle. What effect has ligation of one or both coronary arteries? The heart in two minutes changes its rhythmical movements into twitchings and soon ceases all movement. What is this change due to ? Both to failure of nutrition and to failure in the removal of effete matters from the heart by the blood, as a consequence of which the heart is poisoned by the poisons generated by itself. THE HEART.’ 35 (What are the column® carneae ? They are small ridges of muscular tissue lying on the ventricular wall. What are the musculi papillares ? They are small teat-like muscular projections arising from the inner portion of the ventricular wall, to which the chordae tendineae are generally attached. What is their function ? As the ventricle contracts and the heart shortens they pull the chordae tendineae tense and take up the slack, as it were. what way does the blood circulate through the heart ? Entering the right auricle from the cavae, it passes through the right auriculo-ventricular opening into the right ventricle, then through the pulmonary artery into the lungs, from the lungs through the pulmonary veins to the left auricle, and through the left auriculo-ventricular orifice to the left ventricle, from the ventricle through the aorta, and so on through the arterial system. How much blood is sent out of the left ventricle ordinarily in the adult at one contraction ? About four to six ounces. How much force does the heart put out at each systole ? Enough to lift three foot-pounds.1 Of this the left ventricle does two and a quarter pounds. In twenty-four hours the heart puts out enough force to lift one hundred and twenty-four foot- tons, or enough to lift one ton one hundred and twenty-four feet. What are the movements of the heart ? The chief movements are those of contraction, or systole, and expansion, or diastole. The two auricles contract synchronously, thereby filling the ventricles, then the ventricles contract together, and then follows diastole. Following ventricular diastole there is a pause. 1 A foot-pound represents the force required to lift one pound one foot. 36 ESSENTIALS OF HUMAN PHYSIOLOGY. Systole, diastole, and the pause, therefore, make up one cardiac revolution or cycle. Does the heart change its position during contraction or expansion ? Yes, somewhat; for, with contraction, the base of the heart de- scends, the base of the ventricle goes toward the left but the whole heart rotates a little to the right, and the apex is tilted a little for- ward. The vertical movement of the apex amounts to nothing. At what time does the impulse of the heart take place against the chest ? During systole. What is the object of the pericardium ? It acts as a protecting membrane surrounding the heart. The visceral layer covers the heart and is in turn covered by a reflexion of the membrane which forms the parietal layer. These two surfaces secrete a sufficient quantity of liquid to lubricate their surfaces as they move on one another. When the heart is slowed or quickened, is the change in speed due to a change in systole or diastole, or both? Systole remains unaltered, diastole is prolonged when slowing occurs, shortened when quickening occurs. How many heart sounds have we? Two; the long, dull “lub,” and the short, sharp “ dup.” What are the sounds of the heart due to ? The first sound is due to the vibration of the auriculo-ven- tricular valves made tense by the systolic force of the ventricles, and also the sudden contraction of the muscular fibres of the heart walls. The striking of the apex against the chest wall does not even help the first sound, since it can be heard after the wall is THE HEART. 37 removed. The second sound is produced by the closure of the aortic valves. At what rate does the heart beat ? Before birth, per minute, the beats are 140-150. During first year, per minute, the beats are 125-135. During third year, per minute, the beats are 95-100. During eighth, ninth, and tenth to fourteenth year, 85-90. In the adult, about 72. In very old age, or decrepitude, the pulse once more becomes fast. In which sex is the pulse most rapid ? In females. What effect has posture on the pulse ? The erect posture causes a more rapid pulse than the recum- bent. What other conditions influence its rate ? Respiratory changes, drinking water in small repeated swallows, and many similar conditions. What is the intrinsic nervous mechanism of the heart ? The intrinsic nervous mechanism of the heart consists in three centres, which have been proved to exist in the heart of the frog, and are generally received as the centres for the mammalian heart. The three centres are: 1. The motor ganglion, or that of Remak. 2. The accelerator, or second motor ganglion, or that of Bidder, 3. The inhibitory ganglion, or that of Ludwig. Fig. 1. will serve to illustrate the matter : The motor ganglion (a) sends out through its radiating fibres impulses which drive the heart. The accelerator motor ganglion (6), when it acts, quickens the irradiation of these impulses. The inhibitory ganglion (c) prevents the heart from beating too fast. 38 ESSENTIALS OF HUMAN PHYSIOLOGY a. The motor centre, that of Remak. b. The accelerator motor centre, that of Bidder, c. The inhibitory centre, that of Ludwig, d. The accelerator nerves, e. The pneumo- gastric or inhibitory nerves. The arrows represent direction in which impulses travel What keeps up the contraction of the muscle ? The constant circulation of the blood over the endothelium, thereby stimulating and sending reflex impulses to the motor ganglion. What are the extrinsic cardiac nerves ? The accelerators and the pneumogastric or inhibitory nerves, which arise in the base of the brain and are governed by centres there. What is their function ? They govern the ganglia in the heart muscle. Are the pneumogastric nerves and the accelerators, strictly speaking, antagonists ? They are not, for the accelerators do not act all the time, while the pneumogastrics do, and the vagi can always overcome readily /my accelerator influence. What effect on the heart has stimulation of the pneumo- gastrics It slows the pulse and produces large and full diastole. THE HEART. 39 What effect has section of the vagus ? It produces an exceedingly rapid pulse. What effect has stimulation of the accelerators ? Stimulation of the accelerators makes a very rapid pulse. What is the depressor nerve, and what is its function ? The depressor nerve is given off from the superior laryngeal nerve and the trunk of the vagus in the rabbit, and passes into the cardiac plexus. It conducts impulses from the heart to the vaso- motor centre, and lowers the activity of that centre, thereby relax- ing the bloodvessels somewhat. In this way the heart when over- worked, owing to the increased resistance of high blood-pressure (vasomotor spasm), can be relieved as soon as is necessary. What is the function of the so-called pressor fibres of the laryngeal nerves ? They stimulate the vasomotor centre, causing a rise of blood- pressure. They are, therefore, the direct opponents of the depres- sor fibres. What are the functions of the bloodvessels ? The bloodvessels carry blood to and from the various tissuesand organs. They are divided up into three divisions, known as: 1, Fig 2. Capillary network of fat tissue. (Klein.) arteries and arterioles; 2, capillaries; 3, veins. Of these three, the capillaries are most important in their function, since they not only carry blood, but owing to the peculiarity of their walls, 40 ESSENTIALS OF HUMAN PHYSIOLOGY. bring the blood into intimate relation with the tissues. The fluid which escapes from the capillaries is known as lymph, and the function of lymph is to irrigate and nourish. What is the difference between arteries and veins ? /Arteries differ from veins in having thicker walls, owing to a greater development of their outer coats. Remember! The fact that arteries do not contain valves is not a differential point, since some veins contain no valves. Also that they are not differentiated by the kind of blood they carry, but by their structure ; the pulmonary artery carries venous blood, while the pulmonary veins carry arterial blood. How many coats have the arteries ? They have three coats, known as the outer, or tunica adventitia ; the middle, or tunica media ; the inner, or tunica intima. The last of these is made up of transparent endothelium, composed of irregular, long, fusiform cells held together by a cement substance which is stained black by nitrate of silver (AgNO3). Outside the endothelial coat lies a very thin, more or less fibrous layer, the sub-endothelial; and outside of this is the elastic lamina, which in the smallest arteries amounts to nothing more than a structureless or fibrous membrane, whilst in the other vessels its function is most important. It is known as the fenestrated membrane. The tunica media contains much unstriped muscular fibre, which increases in amount as the vessel grows larger. Most of these fibres are circular, completely surrounding the vessel, while a much smaller number run longitudinally. The tunica adventitia, or the outer coat in the smallest arteries, is a structureless mem- brane which changes into a fibrous membrane as the vessel increases in size. What are the functions of these coats ? The endothelial layer forms a smooth surface over which the blood may pass, and the importance of this will be understood when it is remembered that rough surfaces aid in the coagulation of the blood. The muscular coat regulates the amount of blood received by each part and governs the elastic coat. This is neces- THE HEART. 41 sary, since it is manifest that the heart cannot regulate the blood- supply of each portion of the body. Does the muscular coat aid in the propulsion of the blood ? No; it must be distinctly remembered that in the higher animals, particularly in man, the muscular coat probably aids very slightly in the propulsion of blood. In what way do these coats aid in arresting1 hemor- rhage ? The muscular coat aids, in conjunction with the elastic coat, in the prevention of extensive hemorrhage by contracting the open- ing in the bloodvessel, turning in its edges so that the opening is greatly decreased in calibre. What other function has the elastic coat ? A more important function of the elastic coat is the prevention of sudden pressure in any portion of the body by yielding partially to a sudden strain or controlling a tendency to too great a dilata- tion. It, therefore, equalizes blood-pressure during diastole and systole, and were it not for this important coat the arteries would be entirely emptied during diastole and filled to bursting during systole. What is the function of the outer fibrous coat of the larger bloodvessels ? To protect the bloodvessels from injuries from the exterior and to give the bloodvessel walls support. If it were not for the fibrous coat a ligature applied to a vessel would cut through. What have we in some veins which do not occur in arteries ? Valves which flap back against the wall of the vessel as the blood flows onward, but which prevent any reflux should the current be reversed by any cause. 42 ESSENTIALS OF HUMAN PHYSIOLOGY. How are these valves arranged, singly or in pairs ? In pairs. [s there any difference in the capacity of the various portions of the vascular system ? The combined calibre of the branches of an artery exceed in their capacity that of the parent trunk, and so soon as the muscular coat of an artery is past the capacity of the vascular system is enormously increased. The capillaries are capable of holding eight hundred times as much blood as the aorta. The veins diminish in area as they come toward the heart, whilst the arteries increase as they go toward the periphery. The capacity of a vein is always greater than that of a corresponding artery: even at the heart the capacity of the venae cavae is twice as great as that of the aorta. Fig. 3. Diagram intended to give an idea of the aggregate sectional area of the different parts of the vascular system. A. Aorta. C. Capillaries. V. Veins. The transverse measurements of the shaded part may be taken as the width of the various kinds of vessels, supposing them to be fused together. (Yeo.) What do you mean by blood-pressure ? The pressure under which the blood stream is kept by the action of the heart and the walls of the bloodvessels. THE HEART. 43 Is the blood pressure always constant in man and animals? The blood pressure varies from many causes, and differs in nearly all animals. In the rabbit it can support a column of mercury from two to three and a half inches in height, in the dog from four to five and a half inches, in the horse from eight to twelve inches, while in man the pressure will hold a column of mercury as high as five and three-fourths inches. The pressure in the human aorta is estimated at four pounds and four ounces, in the horse eleven pounds and nine ounces, in the radial artery of man at four drachms, in the pulmonary artery two pounds and two ounces. But it must be remembered that these figures represent the maximum amounts at the moment of ventricular systole. The pressure is least in the capillaries, greatest in the aorta. The venous pressure is only one-tenth that of the arterial pressure. What is the influence of the nervous system on blood pressure ? Nerves supply all the arteries and arterioles, and even the capil- laries and veins, and belong to the so-called sympathetic system. are these nerves called ? Vaso-motor nerves. How are they arranged and governed? By a centre in the medulla oblongata known as the vaso-motor centre, which is situated near the calamus scriptorius and the cor- pora quadrigemina, the tension of the vascular system is governed. Fibres from this centre pass down in the neck through the spinal cord, and find exit with the anterior roots of the spinal nerves. The vaso-motor centre is probably always at work, and to aid it we have scattered through the spinal cord, and in various portions of the body, lesser centres under its control, but capable of originating impulses themselves. proof have we that this is so ? If the cervical sympathetic be cut on one side in the rabbit, or in any animal, that side of the head becomes very rapidly deeply suffused and congested, and remains in this condition for many hours. Finally, however, the color returns almost to normal, and 44 ESSENTIALS OF HUMAN PHYSIOLOGY. congestion goes down. The first dilatation was due to the fact that the governing centre in the medulla by the section, was cut off from that side, and the minor centre not being accustomed to send out powerful impulses, is unable to govern its tributary bloodvessels. In a short time, however, the local centre gathers power, and once more exerts not only its previous influence over the vascular supply of that side, but also is enabled to supplement the action of the higher centre in the medulla, which, before the section, constantly aided it in its efforts. What effect has stimulation of the vaso-motor system on blood pressure ? It raises it by contraction of the bloodvessels all over the body. What effect has depression of the vaso-motor system on blood pressure ? It lowers it by dilatation of the bloodvessels. What effect has division of a vaso-motor nerve on its tributary vessels ? It produces palsy, or relaxation, of its tributary muscles in the wall of the bloodvessel, and, as a consequence, a local or, if the vessels are large enough, indirectly a general fall in blood pressure, by drawing a large amount of blood from the general system. Stimulation of a nerve, on the other hand, produces a contraction of these muscles and a rise of pressure. Blushing is a good example of vaso-motor disturbance of the nervous apparatus governing the vascular system. What effect has galvanization of a sensory nerve on general blood pressure ? It raises it. What effect has it on bloodvessels of a leg in which the sensory nerve is galvanized ? It dilates them and locally lowers pressure. What effect has asphyxia on blood pressure? It increases it by stimulation of the vaso-motor centre in the medulla by the increased amount of CO2 in the blood. THE HEART 45 What effect has section of the spinal cord on blood pres- sure ? It produces a great fall in pressure, due to the cutting off of the vaso-motor centre in the medulla from the vascular system all through the body. \4vhat effect has paralysis of the vaso-motor nerves supply- ing the abdominal bloodvessels ? A general fall in blood pressure all over the body. Why is this so ? Because these bloodvessels are capable of holding all the blood in the body, and so starve the rest of the vascular system. What other causes increase arterial pressure ? Increased heart action, whereby more blood is driven out into the bloodvessels in a given space of time. The increase in heart action may be by increased rate or force, the result is the same. /What are the physical forces of the circulation ? Liquid always goes away from pressure, and the pressure depends on the ease of escape and the forces from behind. If a tube be elastic, and its distal end open and small, it will be found that though the liquid enters it in jerks at the proximal end, it will leave the distal end in a steady stream, but if the tube is rigid the liquid moves in jerks along its whole length. This is the key to the circulation. Under what conditions is the blood placed after being driven out of the ventricle into the arterial system? Just before the arteries are changed into capillaries they are known as arterioles; it is in these arterioles that we still have the muscular coat quite powerfully developed and governed by the vaso-motor system. These muscular coats are kept at a certain degree of tonicity, producing thereby a considerable narrowing of the blood paths, and they, therefore, prevent the blood from flowing out into the capillary system too rapidly. On the other hand, the force given to the blood by the heart has so distended 46 ESSENTIALS OF HUMAN PHYSIOLOGY. the arterial system, particularly in the larger trunks, that the elastic coats have been greatly stretched, and no sooner does the pressure from the heart muscle cease than they contract on the blood. Pressed upon in this manner on all sides, the blood endeavors to find some mode of exit, and is prevented from regurgitating back into the ventricle, in health, by the valves at the aortic opening. As a consequence, the blood obeys the physical law already mentioned, and passes in the direction of least resistance, namely, through the contracted arterioles. yWhat is the function, therefore, of the arterioles ? To prevent too rapid a flow into the capillary system, which, if permitted, would immediately starve both the arteries and veins of their proper amount of blood, since, as before noted, the capacity of the capillaries is extremely great. ' What aids blood flow in the capillaries ? Capillary attraction and pressure due to muscular movements of the body. Also to the action of the heart and arterial coats. What aids blood flow in the veins ? Lateral pressure exerted by contraction of the voluntary mus- cles of the body, the indirect action of the valves in the veins, and, to a slight degree, the heart force. Also, the suction produced by movements of the thorax in respiration (not the heart). Does the blood find it more difficult to return through the veins than to descend through the arteries ? No ; the circulation in this respect resembles a U-shaped tube filled with mercury, in which the column rises on one side, due to pressure or displacement on the other. In other words, the blood descending in the femoral artery shoves the blood up the corre- sponding vein. Is there difference in the rapidity of the flow of the blood in the arteries, capillaries, and veins ? Yes; in the artery the flow is very rapid and in spurts, in the capillaries it is many times slower and generally moves in a steady THE HEART. 47 stream. In the veins the rapidity of the flow increases as the blood nears the heart, but moves in a steady stream, and does not attain the speed of the blood in the arteries. \(What is the pulse f The pulse is caused by a wave of force which travels along the column of blood in an artery as a direct result of a single contraction of the heart; in other words, each pulse represents a heart beat, but not the blood thrown out at that beat. The stroke given by the heart in propelling the blood onward is expended in causing not only the forward movement of the whole mass of blood, but also the lateral expansion already spoken of. As a consequence of this, each pulse is like an expansion wave, causing the vessel to expand by reason of the increased tension and force produced by the heart from behind. \(Is the rapidity of the pulse wave the same as the rapidity of the blood stream in the artery ? No; the main current passes along the vessel at a given rate of speed, while the force of each systole is transmitted along the blood stream as if it were a solid piece of metal or wood, which, having been struck at one end, transmits a wave of force to the other end. The blood being enclosed in partially rigid walls carries the impulse chiefly forward, not laterally. The pulse wave is twenty or thirty times as rapid as the blood current itself. X Does the pulse cause simply a lateral dilatation of the bloodvessel? No ; the bloodvessel is not only widened, but lengthened, so that a straight artery may be seen not only to dilate, but also to become . curved to make up for its elongation. \Is the pulse wave equally strong in all portions of the body ? No; it diminishes in force and in speed as it travels onward, due to the force expended in distending successive parts of the blood- vessel, friction, and other causes. As a consequence of this, the pulse in certain portions of the body occurs an appreciable length of time after the cardiac contraction which has produced it. This 48 ESSENTIALS OF HUMAN PHYSIOLOGY. is noticed particularly in the radial artery, or markedly in the dor- salis pedis artery. The delay, however, even at the most distant point amounts to not more than one-sixth to one-eighth of a second. what speed does the blood circulate ? About ten metres or thirty-five feet per second, and takes but one-third of a second to pass a given point. The length of each pulse wave is, therefore, about three metres (9| feet), or twice the length of the longest artery. When the last part of the pulse wave has passed the arch of the aorta the first part has just reached the arterioles. RESPIRATION. The respiratory apparatus is divided into the larynx, trachea, bronchial tubes, bronchioles, and vesicles in the lung. Surround- ing each lung are the pleurae, one layer of which is attached to the lung (visceral layer), the other to the chest wall (parietal layer). What is the object of respiration'? In order to bring the oxygen of the air in close relationship with the haemoglobin in the blood, and to permit of the elimination of CO2 from the body, as well as other effete products in very minute amount. The enlargement of the chest occurs with inspi- ration, the contraction of the chest with expiration. How many varieties of blood-supply exist in the lung ? Two; the pulmonary artery supply, and the bronchial artery supply. What is the function of these two varieties ? The pulmonary artery supplies the blood for aeration, the bronchial artery that for the nourishment of the lung-tissue itself. what manner is the blood brought to the vesicles and exposed to the air ? The smaller branches of the pulmonary artery split up more and more, and have the peculiarity that they do not anastomose with one another. The fine capillaries run between the air vesicles, the RESPIRATION. 49 thin wall of the vessel and vesicle permitting the free interchange of gases to take place. What difference do we have in the distribution of the bronchial and pulmonary veins from that of the arteries ? The pulmonary and bronchial veins anastomose with one another. Is the circulation more or less rapid in the lung1 capillaries than elsewhere? More rapid, since their area is not so great. Why are the pulmonary veins slightly smaller than the artery? On account of the lessening of fluid due to exhalation of moist- ure in respiration. Are the movements of the lung passive or active ? They are passive, merely following the movements of the chest walls. What are the movements of inspiration ? In inspiration all the diameters of the thorax are increased. The lateral or transverse diameter is increased by the raising of the ribs; the shape of the ribs and their relation to the vertebral column are such as to carry them outward at the same time that they are raised. This same movement carries the sternum for- ward, thus increasing the antero-posterior diameter. The increase in the vertical diameter is due to descent of the diaphragm, the dome-shaped surface of which becomes less arched. For this reason the diaphragm is the most important respiratory muscle. The other muscles concerned in the inspiratory act are the quadrati lumborum, serrati postici inferiores, scaleni, serrati pos- tici superiores, levatores costaruni longi et breves, and intercos- tales externi et intercartilaginei. In forced inspiration the following muscles supplement them: sterno-cleido-mastoidei, trapezii, pectorales minores, pectorales ma- jores (costal portion), thromboidei, and erectores spinse. What are the movements of expiration ? Ordinary expiration is a passive act, brought about by the elastic tension of the lungs, costal cartilages, abdominal viscera, and ab- dominal walls, aided by the weight of the thorax. Contraction of the intercostales interni interossei may assist. In forced expiration 50 ESSENTIALS OF HUMAN PHYSIOLOGY. these muscles are active, as are also the triangulares sterni, mus- culi abdominales, and levatores ani. What effect has sex on respiration ? In men respiration is largely abdominal or diaphragmatic; in women chiefly costal or thoracic. These differences are not due to sex, but to dress and heredity. In young children respiration is chiefly diaphragmatic. Which is longer, inspiration or expiration ? The mean ratio of inspiration to expiration is as 5 : 6. What sounds do we hear on listening to the chest ? The respiratory murmurs, which are produced by the passage of the air in and out of the respiratory apparatus. What do you mean by “tidal air”? The ordinary volume of air respired, amounting to about thirty cubic inches in the adult. What do you mean by “reserve air”? The air which can be voluntarily emitted after ordinary expira- tion. It amounts to about one hundred cubic inches. What do you mean by “complemental air”? The amount which can be taken in after an ordinary inspiration. What do you mean by “residual air”? It is the amount which remains after forced expiration, equalling about one hundred and twenty cubic inches. What does the term “vital capacity” mean? The greatest amount of air which can be emitted after forced inspiration, and is therefore the sum total of reserve, tidal, and complemental air. It varies with age, sex, size, posture, and oc- cupation. The total quantity in an adult, passing in and out in twenty-four hours, is 686,000 cubic inches; in hard-working labor- ers, 1,568,390 cubic inches. For every inch of height above five feet one inch the capacity should increase eight cubic inches. What influence has sex on capacity ? Females have less capacity than males where the chest has the same circumference. RESPIRATION 51 How many respirations a minute ? Fourteen to twenty, but the number is influenced by sex, the age, and position, also by exertion. The size of the animal governs rapidity. The mouse breathes very rapidly; the elephant only eight times per minute. What effect has the law of the diffusion of gases on res- piration ? In the vessels we have a large amount of CO2, while in the air we breathe we have an excess of 0. According to this law, there- fore, the O attempts to get in as the C02 attempts to get out. This law also prevents the reserve and residual air from becoming laden with C02. The change is assisted, too, by the different temperatures of the air within and without. What amount of work is performed by the respiratory muscles ? The work done by the respiratory muscles is estimated by Haughton at 21 foot-tons in twenty-four hours. What changes have we produced in the atmospheric air by respiration? 1. Increase in its temperature. 2. Increase in C02. 3. Increase in organic matter and free ammonia. 4. Increase in watery vapor. 5. Diminished amount of O. The expired air is hotter than the inspired as a general rule, but on a hot day, with the atmosphere above 98.8° F., it is cooler. The temperature varies from 97°-99J° F., according to the length of time the air remains in the lungs. Is the amount of C02 exhaled constant? It varies at all hours of the day, and is influenced by many con- ditions. The C02 given off by a normal man in an hour equals 1346 cubic inches, or 636 grains. Accordingly we have 173 grains of carbon given off in an hour, or 8 ounces in twenty-four hours. Time of day, varieties of food, and exercise, greatly influence the amount of C02. ESSENTIALS OF HUMAN PHYSIOLOGY. 52 Does age affect the amount of C02? Yes; CO2 increases in amount from 8 to 32 years, while from 35 to 50 it remains stationary, or slightly falls. After 50 years it constantly diminishes. At 80 years it scarcely exceeds that of a child of 10 years. How much 0 is abstracted from every volume of air ? About 41 per cent, What effect has quickening of the respiratory movements on the amount of C02? The quicker the respirations the less CO2 in each respiration, but the aggregate amount is increased. What portion of the expired air contains the most CO2? That of the last half of expiration. What effect has the condition of the atmosphere on the amount of CO2? More CO2 is given off when air is moist than when it is dry. What influence has the time of day on the relative amounts of C02 and 0? During the day more CO2 is exhaled than O is taken in; while at night the reverse is the case. In other words, there is a reserve fund of O stored up at night to meet the exigencies of the day. Is a very large amount of watery vapor given off by the lungs ? Yes; almost enough to saturate the expired air. The amount equals 6 to 27 ounces in twenty-four hours. The average amount is from 9 to 10 ounces. Does ammonia exist as a physiological constituent of all expired air? No; it does not. It is chiefly derived from decomposition pro- ducts in the mouth. RESPIRATION. 53 The Nervous Mechanism of Respiration ' Is respiration purely an involuntary act ? No, it is not; since we can '‘hold the breath,’’ or breathe rapidly or slowly, superficially or deeply, as we choose. That it is in- voluntary to a great extent is proved by the fact that one does not stop breathing when asleep or unconscious. Respiration is governed by a centre, the respiratory centre, in the medulla oblongata near the calamus scriptorius. What keeps this centre active ? It is kept active by the condition of the blood. If the amount of O is too small the centre sends out impulses and increases respiration. describe this centre more fully. There is a respiratory centre on each side of the medulla oblongata, and these may in turn be divided into two centres, namely, the greater one for inspiration and lesser for expiration. Does the expiratory centre constantly send out impulses ? No; it is only active on rare occasions, as when there is some obstruction to respiration. Are there any centres for respiration higher up in the nervous system than the medulla oblongata ? No. All phenomena which have suggested such a centre can easily be explained as centripetal stimulations of the medulla oblongata, which by reflex action act on the respiratory centre in the fourth ventricle. Are there any respiratory centres in the cervical part of the cord ? No. Only the tracts which carry the impulses. What do you mean by eupnoea, apnoea, and dyspnoea ? Eupncea is normal breathing; apnoea is a condition in which too much 0 is absorbed into the blood, and is readily produced by forced artificial respiration. Remember, that the use of the word apnoea to indicate a condition in which breathing has ceased from the ordinary causes, is incorrect. Breathing in apnoea ceases from 54 ESSENTIALS OF HUMAN PHYSIOLOGY. the excess, not the lack, of oxygen. Dyspnoea is labored or diffi- cult breathing. What effect has the pneumo gastric apparatus on respi- ration ? If both vagi are cut the respirations become somewhat deep and full. If these nerves are stimulated the respirations become very rapid and violent. Is this change due to a direct transmission of the stimulus along the nerves to the lungs, or to a reflex wave to the respiratory centre ? It is due to a reflex wave to the respiratory centre. Remember, that the vagus nerves are made up of both efferent and afferent fibres. Also remember, that not only do we have an efferent and afferent set of fibres, but that the afferent fibres are made up them- selves of two sets of fibres, one of which, the central end of the superior laryngeal branch, after it has been cut, when stimulated slows the respirations, while stimulation of the central end of the vagus itself quickens the respirations. When the nerve is stimu- lated the impulse goes upward to the centre, and from there is irradiated down to the organs. Sighing is a long inspiration. When great attention is being paid we speak of “ shallow breathing.” In other words, we almost forget to breathe. Sighing always follows this condition, and makes up for the shallow breathing before it. Hiccough is a sudden inspiration due to descent of the diaphragm. Coughing is expiratory. Sneezing is expiratory, but is preceded by a full inspiration. In speaking we expire. Sobbing consists of a series of short inspirations, after each of which the glottis is closed. Laughing is a series of short and rapid expirations. DIGESTION. What three forms of digestion have we ? Salivary, gastric, and intestinal. DIGESTION. 55 What is the function of salivary digestion ? To convert starch into maltose. On what does the gastric digestion act ? On the proteids, converting them into peptones. What part of digestion is carried on in the small intestine ? The fats are prepared for absorption by being emulsified, the proteids converted into peptones, and starch is changed to maltose and dextrose. The salivary secretion is derived from what three glands ? The submaxillary, sublingual, and parotid. The mucous glands present in the mouth are solely for the purpose of lubrication. Describe the characteristics of the saliva. It is a mixture of the secretion of the three glands named, and is a slightly turbid, tasteless fluid of a distinctly alkaline reaction. The specific gravity is 1003. It contains five-tenths per cent, of solids, the greater part of which are organic, such as mucin, which produces the viscidity, traces of albumin, and a peculiar ferment, ptyalin. The inorganic constituents are salts, the chief one of which is potassium sulphocyanide, which may be readily per- ceived by its odor when saliva is kept for a short time in a test tube. The other portions of the saliva are made up of salivary corpuscles which contain nuclei, and are probably altered leuco- cytes, epithelial cells, and various microorganisms. How much saliva is secreted in twenty-four hours ? From 7 to 70 ounces. What is the difference between parotid saliva and that of the other glands ? It contains more ptyalin, a smaller amount of urea, traces of a volatile acid, and some inorganic constituents, as salts of soda and potash; it contains no mucin, and is much thinner than is the secretion of the submaxillary or sublingual glands. Describe the submaxillary saliva. Submaxillary saliva is markedly alkaline, tenacious, and con- tains mucin; it contains much less ptyalin than does parotid saliva. 56 ESSENTIALS OF HUMAN PHYSIOLOGY. Describe the sublingual saliva. Sublingual saliva is more sticky and cohesive than either of the others, and contains much mucin, salivary corpuscles, and potas- sium sulphocyanide. What is the nerve supply of the salivary glands ? The submaxillary glands are supplied by the chorda tympani, which is derived from the facial nerve. It also receives filaments from the superior cervical ganglion of the sympathetic, and from the submaxillary ganglion. Remember, that the chorda tympani contains two sets of fibres : 1st, true secretory fibres ; 2d, vaso-dilator fibres. The sympathetic also contains two sets of fibres: 1st, true secre- tory ; 2d, vaso-constrictor fibres. The sublingual glands are supplied by the same nerves as supply the submaxillary. The parotid glands are supplied by branches of the facial which join the auriculo-temporal branches of the fifth pair of cranial nerves. What is the effect of section of the chorda tympani ? The flow of saliva is very greatly decreased. What is the effect of stimulation ? Increased salivary flow and increased glandular vascularity. • What is the effect of stimulation of the facial nerve at its origin in the floor of the fourth ventricle ? It increases the salivary flow from the submaxillary gland. What is the effect of stimulation of the sympathetic ? It causes a decrease in the salivary flow, with contraction of the bloodvessels and consequent decrease in vascularity. Does the increase in salivary flow depend upon increased vascularity ? No; since if all the bloodvessels going to the gland be tied, secre- tion is still increased either when the chorda tympani is stimulated or when the sympathetic is paralyzed ; under these circumstances the extra liquid required is obtained from the lymph vessels and spaces. Atropine and daturine are drugs which decrease salivary secretion by depressing the chorda tympani peripherally. DIGESTION. 57 Tiemember, that mere increase in vascularity in the salivary glands does not of necessity increase the flow of saliva. The only influence which increased vascularity exerts is a greater supply of liquid which escapes from the gland rather by leakage than by secretion. Is the pressure in the excretory ducts of the salivary glands very great ? Yes ; Ludwig has found that the pressure in these ducts may be twice as great as the blood-pressure in the carotid itself. The pressure in Wharton’s duct may equal 200 millimetres of mercury. What is the cause of the great pressure in the salivary ducts ? It is due to the secreting power of the cells in the gland. What change in temperature occurs in the gland ? During secretion the temperature of the gland rises, so that it is often warmer than the arterial blood. How do you produce increased salivary flow from the parotid ? By stimulation of the facial nerve after it has joined the auriculo- temporal branch of the fifth or trifacial nerve, or reflexly by stimu- lation of the glosso-pharyngeal nerve. In what way is secretion brought about when food enters the mouth ? Reflexly through the lingual branch of the glosso-pharyngeal and the inferior maxillary branch of the trifacial or fifth nerve, which carry the impulses up to the centre in the medulla. What effect has section of the chorda tympani on this reflex ? If the chorda tympani be cut previous to the introduction of a substance into the mouth no increase of flow comes from the glands which it supplies; but if the sympathetic be cut the reflex, although partially interfered with, is not prevented. Is the rate of secretion always the same ? No; it varies according to the condition of the mouth and the food in it. What effect have the movements of mastication on the salivary flow ? They increase it. 58 ESSENTIALS OF HUMAN PHYSIOLOGY. In what condition is an increased flow of saliva pro- duced ? When nausea is present, profuse salivary secretion occurs by a reflex through the vagus nerve. What is the physiological action of saliva ? Its most important action is its diastatic or amylolytic action, or, in other words, the transformation of starch into dextrins, and of dextrins into maltose. What do you mean by the term diastatic ? The power which certain substances have of acting on starch and converting it into sugar. Upon what does the diastatic power of saliva depend ? Upon ptyalin. Is the ptyalin destroyed when it acts ? Scarcely at all, for it acts by catalysis, or its mere presence. What effect have high and low temperatures on the action of ptyalin? High and low temperatures prevent its action, and boiling and freezing stop it absolutely. What is the sugar called which is formed by the action of the saliva ? The sugar formed by the action of saliva on starch is maltose, which is converted into dextrose by an inverting enzyme in the small intestine. It is in the form of dextrose, or dextrose and levulose, that the carbo-hydrates are absorbed. What is the object of boiling starchy foods ? In order to break up the cellulose coverings of the starch gran- ules, and enable the diastatic ferment to attack the starch. What is the first change in the starch as it is digested ? It becomes liquefied. What are the mechanical uses of saliva ? It keeps the mouth moist, facilitates speaking and the mastica- tion of food, also the movements of the tongue. It dissolves certain substances, and renders them capable of being tasted; by DIGESTION. 59 mixing with food it forms a soft bolus which is easily swallowed and digested. What are movements of mastication ? 1. The elevation of the jaw is accomplished by the combined action of the temporal, masseter, and internal pterygoid muscles. 2. The depression of the jaw by its own weight, aided by the action of the anterior bellies of the digastrics, mylo-hyoids and genio-hyoids, and the platysmas. 3. The displacement of the articular surfaces backward or for- ward is produced, when forward, by the external pterygoid muscles which pull the jaw down and forward. As one external pterygoid acts it pulls the jaw sideways and we have a grinding movement. When the movement is backward the digastric and hyoid muscles act. What is the function of mastication ? We divide, by this means, the food into small pieces, biting it off by the incisors, tearing it off by the canines, and grinding it up by the molars. Soft food is broken up by the tongue pressing it against the roof of the mouth. By this means the digestive fluids may attack the food more readily. What is the function of the tongue in mastication? To keep the food between the teeth, in which it is assisted by the muscles of the lips and the buccinator muscles. In what way is deglutition accomplished ? 1. The aperture of the mouth is closed by the orbicularis oris. 2. The javys are pressed together by the muscles of mastication. 3. The tip, middle, and root of the tongue, one after the other, are pressed against the hard palate, thereby propelling the food backward. Just at this time the levator palati draws the soft palate upward and backward, completely closes the posterior openings ol the nasal cavities, and the intrinsic muscles of the larynx firmly close the rima glottidis. 4. After the anterior palatine arch is passed, it is prevented from returning to the mouth by the palato-glossi muscles, lying in the anterior pillars of the fauces. 5. The bolus is now urged on, first, by the action of the superior constrictors of the pharynx, next the middle, and third the inferior constrictors. 60 ESSENTIALS OF HUMAN PHYSIOLOGY. 6. Having reached the oesophagus, it is urged on by the outer longitudinal and the inner circular non-striped muscular fibres, which contract peristaltically. Recent experiments show that this peristalsis only occurs on forced deglutition, the food ordinarily being projected into the oesophagus by the voluntary muscles. is the nervous mechanism of deglutition ? The centre for swallowing is in the medulla oblongata. The efferent nerves which govern deglutition are: the hypo-glossal, which supplies the hyoid or tongue muscles; the glosso-pharyngeal and vagus nerves to the pharyngeal plexus, which supply the con- strictor muscles; and the facial and fifth, which supply the fauces and palate. The movements of the oesophagus are governed both afferently and efferently by the vagus, which also acts with the superior maxillary branch of the trifacial. The afferent vagus filaments for the first part of deglutition are the pharyngeal branches of the anterior laryngeal branches. The Stomach. What varieties of cells do we find in the stomach ? In the cardiac end of the stomach we have two distinct kinds of cells. One kind, the most numerous, consists of small, pale, spheroidal cells which line the interior of the glands. The other cells are much fewer as well as larger, and are scattered over the fundus of the glands. What two sets of glands have we in the stomach ? The mucous, which are chiefly situated at the pyloric end of the stomach, and those which secrete gastric juice. What are the movements of the stomach ? When the stomach is empty it lies with its greater curvature downward and its lesser upward; when it is full the greater cur- vature swings forward against the abdominal wall, while the lesser curvature approximates itself to the spinal column. What other gastric movements have we ? We have two distinct varieties of gastric movement different from the two mentioned: the first is a rotatory or churning move- ment whereby the walls glide over the food, these movements occur periodically and last for several minutes, their function is to moisten the food by the gastric juice and break it up; the other is DIGESTION. 61 Fig. 4. Diagram of a section of the wall of stomach, a, orifices of glands, with cylindrical epithelium, b, fundus of glands, with spherical and oval epithelium, c, muscularis mucosae, d, submucous tissue, containing bloodvessels, etc. e, circular ; f, oblique, and g, longitudinal muscle coats, h, serous membrane. (Yeo.) Diagram showing the relation of the ultimate twigs of the bloodvessels (V and A) and of the absorbent radicals (L) to the glands of the stomach, and the different kinds of epithelium, viz.: above cylindrical cells; small, pale cells in the lumen; outside of which are the dark ovoid cells. (Yeo.) 62 ESSENTIALS OF HUMAN PHYSIOLOGY. the peristaltic movement whereby the food is pushed out into the duodenum through the pylorus. Whaf are the intrinsic and extrinsic nerves of the stomach ? Auerbach’s plexus is the motor portion of the apparatus. The left vagus supplies the anterior surface of the stomach, the right vagus supplies the posterior surface. Describe the gastric juice. It is a tolerably clear, colorless fluid (straw-colored), of acid reac- tion, sour taste, and peculiar characteristic odor; it is not rendered turbid by boiling and resists putrefaction for a long time; its spe- cific gravity is 1002.5. The quantity secreted in twenty-four hours amounts to from eight to fourteen pints. What does the gastric juice contain? First, pepsin, the characteristic nitrogenous hydrolytic ferment, which dissolves proteids; second, hydrochloric acid, the chief acid present; also small amounts of lactic acid. The latter, however, is not secreted, but is due to decomposition of carbo-hydrates in the stomach. Which cells secrete the greatest amount of pepsin ? Those at the cardiac end of the stomach. Does pepsin exist in the glands ready formed? According to most physiologists it is due to the presence of a compound known as pepsinogen, which forms pepsin as soon as it comes in contact with hydrochloric acid in the stomach. What is the function of lactic acid ? It digests the proteids in much the same manner as does hydro- chloric acid. secretion go on constantly in the stomach ? No. Only on the entrance of stimuli, such as food, etc. What change takes place in the gastric mucous membrane on the entrance of food ? It becomes red and the circulation more active. What happens to the gastric juice when the food passes out of the stomach into the alkaline intestine ? It is neutralized and part of the pepsin reabsorbed. DIGESTION. 63 What is chyme ? The mixture of food and gastric juice. What effect has gastric juice upon proteids ? It changes the proteids first into a substance known as syntonin or acid-albumin, which is immediately changed again into pro- peptone or hemi-albuminose or para-peptone. The para-peptone is now converted into peptone, which is absorbed into the blood from the small intestine and immediately converted back again into proteids, and so deposited in the tissues. Does pepsin suffer any change when acting ? It acts chiefly by catalysis, but is partially destroyed. (For properties of peptones and para-peptones, see page 19.) Is any albumin absorbed unchanged ? According to Yeo, a considerable quantity of albumin is absorbed unchanged, both from the stomach and intestines. What other special ferment have we in the stomach ? The milk-curdling ferment. What is the action of the gastric juice on carbo-hydrates ? It has no effect on starch, inulin, or the gums. Cane-sugar is slowly changed by it into dextrose and levulose. Why does not the stomach digest itself? There is much discussion in regard to this point. No satisfac- tory explanation has been given. Some physiologists teach that the protection which the coats of the stomach, during life, seem to have is due to the constantly circulating alkaline blood through them. This explanation is unsatisfactory, as it does not explain why the small intestine is not digested by its alkaline fluids. All that can be said in either case is that living tissue is protected from self-digestion by the properties of its living structure. gases have we in the stomach ? Those which are derived from the air which is swallowed with the saliva and those which regurgitate from the duodenum. Besides these we have gases which arise in cases of dyspepsia from fermen- tative and putrefactive changes in the food. < 64 ESSENTIALS OF HUMAN PHYSIOLOGY. What is the mechanism of vomiting ? It is caused by contraction of the walls of the stomach, whereby the pyloric sphincters are closed. It occurs most easily when the stomach is distended, and in infants, owing to the peculiarity of the position of their stomachs, the regurgitations of milk are due to scarcely more than reverst d peristalsis. In children, therefore, the abdominal muscles do not always aid in the expulsion of food. In adults they always do. In what way is vomiting produced ? Vomiting is produced either by an action on the peripheral ends of the nerves of the stomach or by direct action on the vomiting centre in the medulla. What effect has section of the vagi on vomiting ? It prevents it. Do we ever have bile in vomit ? Frequently when the vomiting is so severe as to cause the bile to flow out of the duodenum into the stomach. What is the movement called by which food is passed along through the intestines ? Peristalsis. In what portion of the intestinal tract is peristalsis most marked ? In the small intestine. What is peristalsis ? Peristalsis is the constantly moving onward of a contractile wave along the wall of the gut, or, in other words, is the progressive narrowing of the tube from above downward. Do the movements of the stomach and intestine continue during sleep ? Some physiologists believe that they do; others that they do not. The matter is largely one of opinion, but it is probable that the first opinion is the correct one. DIGESTION. 65 What do you mean by reversed peristalsis ? A condition in which the peristaltic wave travels from below upward, the cause of which has been supposed by some to be due to the fact that one band of the muscular fibres in the gut misses a contraction. What are the functions of the muscular coat of the intes- tine ? To carry on peristalsis. What nervous influence is exercised over intestinal move- ments ? Auerbach’s plexus is the automatic motor centre which lies between the muscular coats and produces peristaltic movements in sections of the gut removed from the body. Meissner’s plexus is much less important, supplying only a few motor fibres to the muscular coats, and a few motor and sensory fibres to the muscularis, mucosae, and intestinal glands. What do you mean by aperistalsis ? An absolute abolition of peristaltic movement. Normal peris- talsis is known as euperistalsis. When peristalsis becomes very violent it is known as dysperistalsis. What influence has the circulation of the blood on peri- stalsis ? Violent peristaltic movement is produced by interrupting the circulation of blood in the wall of the gut, whether the stoppage is due to congestion or anaemia of the parts. This is the cause of the marked peristalsis preceding death. What are the inhibitory nerves of the gut ? The splanchnics, which, however, also contain motor filaments. What effect has stimulation of the splanchnics on peri- stalsis ? If the blood supply is normal it slows or prevents them. If abnormal, it increases them. The reason of this is that the inhibi- tory fibres of the splanchnics are paralyzed by venous blood in the gut, but the motor fibres are not. 66 ESSENTIALS OF HUMAN PHYSIOLOGY. Pancreatic Digestion. Describe the pancreas. The pancreas is a large racemose gland attached by its lateral brancblets to its main central duct. The cells making up the gland may be divided into two zones, an external homogeneous zone and an internal granular zone. Each zone corresponds to one-half of the cells, the clear half being next the boundary, and the granular half being next the lumen of the saccule. Fig. 6. One saccule of the pancreas of the rabbit in different states of activity. A. After a period of rest, in which case the outlines of the cells are indistinct, and the inner zone — i.e., the part of the cells (a) next the lumen (c)—is broad and filled with fine granules B. After the gland has poured out its secretion, when the cell outlines (d) are clearer, the granular zone (a) is smaller, and the clear outer zone is wider. (Kuhne and Lea.) Describe the pancreatic juice. Pancreatic juice is thick, transparent, odorless, and saltish in taste. The saltish taste is due to the presence of sodium carbonate; if acid be added CO2 is liberated. It acts powerfully as a digestive agent. What is the appearance of the pancreas when at rest and at work ? During digestion it is red and turbid, and at other times pale and anaemic, DIGESTION. 67 What is the function of the pancreatic juice ? It contains at least four hydrolytic ferments, and is, therefore, a most important digestive fluid. What are these four pancreatic ferments ? (1) The diastatic action is caused by a ferment known as amylop- sin, a substance which seems to be identical with the ptyalin of the saliva. What is the difference between the action of this ferment and ptyalin on starch ? It is much more powerful than ptyalin. (2) The tryptic action, which is caused by the presence of a sub- stance known as trypsin, or pancreatin, which acts on proteids converting them into peptones, or, as they are sometimes called, tryptones. The intermediary product between a proteid and a tryptone is alkali-albumin, corresponding to the acid-albumin of gastric digestion. What are leucin and tyrosin ? Substances normally found in the small intestine produced by a too prolonged action of trypsin on its self-formed peptone. They are crystallizable nitrogenous bodies. What are skatol and indol ? Strong, stinking decomposition products resulting from the con- tinuation, pathologically, of this action of trypsin on peptone. What is the difference in the manner in which trypsin acts on albuminous matters from that of the gastric juice? In gastric digestion fibres of meat swell up before they are dissolved. In pancreatic digestion they do not swell up but become eroded. 68 ESSENTIALS OF HUMAN PHYSIOLOGY. What reaction is necessarily present for the pancreatic action to take place ? An alkaline reaction. What is the alkali commonly present ? Sodium carbonate, the presence of which is as necessary to th" pancreatic action as hydrochloric acid is to the peptic action. What two forms of tryptones have we? One known as anti-peptone, the other as hemi-peptone. What is the action of the pancreatic juice on fats ? It first forms them into a fine emulsion, and secondly causes them to take up a molecule of water and split up into glycerine and fatty acids. This action of the pancreatic juice is due to the third ferment, known as steapsin. According to Kiihne and Roberts the pancreas contains, fourth, a 'milk-curdling ferment. The four are, therefore, as follows: amy- lopsin, trypsin, steapsin, and the milk-curdling ferment.- At what time is the pancreatic juice poured out ? On the entrance of food into the small intestine coming from the stomach. THE LIVER. The anatomy of the liver is so closely concerned in its physio- logical functions that an outline seems unnecessary at this point. It will be remembered that the liver is made up of many little livers known as lobes and lobules, each lobule being a perfect gland in itseif. The bloodvessels are derived from two sources, first, the venous, which enter by means of the vena porta; and which, branch- THE LIVER. 69 ing, give off numerous interlobular vessels or veins forming dense plexuses around the lobules. Branching off from these interlobular vessels are the capillaries which converge to the centre of the lobule, forming elongated meshes, between which are rows of cells. Fig. 7. Section of lobule of liver of rabbit in which the blood and bile capillaries have been injected (after Cadiat). a. Intralobular vein. b. Interlobular veins, c. Biliary canals beginning in fine capillaries. These capillaries on reaching the centre of the lobule form the intralobular vessel or central vein, which again joins together with 70 ESSENTIALS OF HUMAN PHYSIOLOGY. others and forms the radicles of the hepatic veins. The second set of bloodvessels are branches of the hepatic artery which dip down between the lobules to nourish the whole gland tissue whatever it may be. The third set of vessels which are present are known as the bile-ducts, which, arising from the centre of the lobule join one another and form the interlobular bile ducts, which anastomose and finally form the common biliary duct. Fig. 8. Section of the liver of the newt, in which the bile ducts have been injected, and can be seen to form a network of fine capillaries around the liver cells, the outlines and nuclei of which can be seen. What is the chemical composition of the liver cells ? First, proteids or albuminous matters. Second, glycogen, or animal starch, which is a true carbo-hydrate, and is changed into sugar by a diastatic ferment. What conditions influence the quantity of glycogen ? The eating of large quantities of starch, milk, fruit, or cane-sugar increases it greatly, while purely albuminous or fatty diets decrease it greatly. What are the sources of glycogen ? It is probably derived from the carbo-hydrates of the food. THE LIVER. 71 What are the functions of the liver ? The functions of the liver are three—the secretion of bile, the formation of glycogen, and the destruction of worn-out blood cells. What is the use of glycogen in the body ? It is not really known. Describe the bile. Bile is a yellowish-brown or dark green transparent fluid with a neutral reaction and a bitter taste. Its specific gravity is from 1010 to 1050. What does bile contain ? First, mucus, which makes it viscid, and which comes from the walls of the gall-bladder. Second, the bile acids, glyco-cholic and tauro-cholic acids, which unite with soda, forming cholates. Which of the bile acids occur in human bile ? Both are usually present, though tauro-cholic may be absent. What is Pettenkofer’s test for bile ? Add concentrated H2SO4 drop by drop, then add a ten per cent, solution of cane-sugar when a reddish purple color is struck. What is Heintz’s test ? Heintz’s test consists in adding nitric acid, when a play of colors results. What are the bile pigments ? Bilirubin, which is yellowish-brown ; biliverdin, which is green; bilifuscin, biliprasin, and hydro-bilirubin, the last being the normal coloring matter of the feces. What is cholestrin ? Cholesterin is an univalent alcohol which occurs in the yolk of eggs, and in solution in the bile. Is the secretion of bile a mere filtration of substances already in the blood ? No; it is a true secretion, being produced by the cells of the glands. 72 ESSENTIALS OF HUMAN PHYSIOLOGY What is the quantity of bile secreted per day ? About seventeen ounces. What is the difference between the contents of the blood- stream in the hepatic vein and the portal vein ? The hepatic vein contains more sugar (?), cholesterin, and blood- corpuscles, and less albumin, fibrin, free haemoglobin, fats, water, and salts. In what way is the coloring matter of the bile obtained ? By destruction of worn-out blood corpuscles. What are the functions of the bile ? The emulsification of the fats, the lubrication of the walls of the intestine, and to increase the osmotic power of the wall of the gut in order to facilitate the absorption of fats. It also prevents to a very considerable extent decomposition and stimulates peristalic action. What is the fate of bile in the intestine ? Some of it passes out with the feces, and part is absorbed and eliminated as urobilin. The cholesterin is given off with the feces, and the bile salts are for the most part reabsorbed by the gut. Have the other juices of the small intestine any digestive power ? They probably have some power in the solution of the proteids, and perhaps a diastatic action. What is the fate of the salivary, gastric, and pancreatic ferments ? Ptyalin is destroyed in the stomach by the acid pepsin, and the milk-curdling ferment by the alkaline salts of the pancreatic and intestinal juices and by trypsin, the diastatic ferment of the pan- creas by acid fermentation in the large intestine. What is the function of the large intestine ? It absorbs the liquids from the fecal matter coming from the small intestine. What is the amount of feces in twenty-four hours ? Six to twenty ounces according to the character of the food. ABSORPTION. 73 ABSORPTION. Fig. 9. Diagram showingthe course of the main trunks of the absorbent system. The lym- phatics of lower extremities, etc., meeting the lacteals of intestines at the receptaculum chyli (R. C ), which opens into the thoracic duct. The superficial vessels are shown io the diagram on the left arm and leg (S), andthe deeper ones on the arm to the right (D). The glands are here and there shown in groups. The small right duct opens into the veins on the right side. The thoracic duct discharges into the union of the great veins of the left side of the neck. (Yeo.) The mucous membrane of the whole alimentary canal is capable of absorption, some portions more so than others. Describe the intestinal mucous membrane. In the mucous membrane are found small glands of two kinds— the first are Brunner’s glands, and are localized in the duodenum, the others are those of Lieberkuhn, which are distributed over the entire intestinal tract in great numbers. 74 ESSENTIALS OF HUMAN PHYSIOLOGY. What is a villus ? A small process from the wall of the intestine, containing blood- vessels and a lacteal. In what two ways does absorption occur ? By means of the blood-capillaries and the lacteals. What substances are absorbed by the capillaries and what by the lacteals ? The first absorbs sugars and proteids, the lacteals the fats. Ftg. 10. Drawing of transverse section of duodenum, showing Brunner’s glands (B) opening into Lieberkuhn’s follicles (L); V, villi; M, muscular coats. (Yeo.) What portion of the gastro-intestinal tract carries on the greatest amount of absorption ? The upper half of the small intestine. What is the position of the lacteal ? It lies in the axis of the villus, and is surrounded by a blood- vessel and a vein. The lacteals anastomose in the sub-adenoid tissue of the gut, and finally form lymphatic networks which end in the receptaculum chyli, the beginning of the thoracic duct which opens into the subclavian vein on the left side near the junction of the jugular. The villi are possessed of unstriped muscular fibres, which aid in emptying the lacteal, and the nerves which supply them are derived from Meissner’s plexus. What three forces are at work in the absorption of digested food ? Endosmosis, diffusion, and filtration. ABSORPTION". 75 What do you mean by endosmosis and diffusion ? Endosmosis is the change which occurs between two fluids which are capable of forming an intimate mixture with each other through an animal membrane, but never between two fluids which do not Fig. 11. Villus, with capillaries injected, showing their close relation to epithelium, some of the cells of which are distended with mucus. (Cadiat.) form a perfect mixture, such as oil and water. Diffusion is the mixing of two liquids placed one over the other in a vessel without the presence of a septum. What is the law in regard to the diffusion of crystalloids and colloids? Crystalloids will diffuse into colloids, but colloids will not diffuse 76 ESSENTIALS OF HUMAN PHYSIOLOGY. into crystalloids. Filtration occurs in the small intestine simply by the pressure which is exerted upon the fluid by the contraction of the walls, and also by a negative pressure or suction produced by the villi. What is the influence of the nervous system on absorption ? Our knowledge is limited, but it has been found that after extir- pation of the semilunar ganglion of Budge, or section of the mesen- teric nerves, the intestinal contents became very fluid, which may be due to diminished absortion. ANIMAL HEAT. What do you mean by the term animal heat? The temperature at which the body of a warm-blooded animal is maintained. What is the normal temperature of man ? 98f° F. Is it constant in all persons ? It varies but a fraction of a degree. Do all animals have the same temperature as man ? No ; birds have as high as 107° F., and dogs as high a tempera- ture as 103° F. In the lower animals the bodily temperature of members of the same species often varies. Upon what does the temperature of cold-blooded animals depend ? Upon the temperature of the surrounding medium. What conditions influence bodily temperature ? Age, sex, period of day, exercise, climate and season; food and drink also influence it. What is the effect of age ? The temperature of a newborn child is one degree above that proper to the adult. In full adult life the temperature is lower than at any other time since it rises again in old age. ANIMAL HEAT. 77 What effect has the period of day? The variation may equal one to one and a half degrees, the mini- mum late at night or early in the morning; the maximum late in rhe afternoon. What is the effect of exercise ? It raises the temperature; but physiologists differ as to the actual amount of increase thus, some state that the rise of temperature produced by exercise never raises the general bodily temperature more than about 1° F., while others believe that it raises it much more. Those who think the actual general rise is slight, believe that the great rise occurring in tetanus, where all the muscles con- tract, is due to some other concomitant pathological condition. Students must be governed in regard to this point by the opinion of their instructor. Climate and season have very slight influence over the bodily temperature. What variations in bodily temperature may we have in disease? In fever we may have a temperature as high as 106° and 110°, or even 115° F. In Asiatic cholera it sometimes falls to 77° or 79°. What difference is there in the temperature of different portions of the body ? The surfaces of the hands and feet are cooler than any other portion of the body, while the liver often is as high as 105° F. From what source is animal heat derived ? The ultimate source is contained in the potential energy taken into the body with food and with the oxygen during respiration, but the amount of heat formed depends upon the amount of kinetic energy liberated. The energy of the food stuffs may be called “latent heat.” (For definitions of these terms, see Bodily Me- tabolism.) What are the direct sources of heat ? The blood during digestion becomes laden with more carbon, hydrogen, and oxygen than is needful for the repair of the tissues, and these gases uniting with the sulphates develop heat by chemi- 78 ESSENTIALS OF HUMAN PHYSIOLOGY. cal means very rapidly, while the rest of the heat of the body i4z more slowly developed by a slower combustion. The brain, the muscles, and the glands manufacture heat, so that venous blood leaving one of these parts is warmer than arterial blood. Is there any difference in the heat-producing properties of different food stuffs ? Fat are particularly heating, giving more kinetic energy. What is the nervous mechanism of animal heat ? In the brain is seated a heat centre whose function it is to direct the rapidity of combustion or the development of heat in the body. Governing this centre are two others, the inhibitory heat centre (Wood), whose function it is to prevent a too rapid production of heat, and the accelerator heat centres (Sachs and Aronsohn), whose function it is to increase the production of heat. What two functions govern the temperature of the body? Heat production and heat dissipation. Heat production consists in the manufacture of a certain number of heat units or calories in a given space of time in the body, while heat dissipation is the function by which a certain number of heat units are given off from the body to the surrounding atmosphere or medium. What is the effect of increased heat production and de- creased dissipation? Increase in temperature, or, in other words, fever. What is the effect of a decrease in heat production or an increase in heat dissipation ? A fall of temperature. Remember that these two functions balance one another and that disorder of either of them either raises or lowers bodily temperature. Under what circumstances is the dissipation of heat in- creased ? By cold surroundings, by conditions which bring large quan- tities of heat to the surface of the body, and by contact of the body with substances which readily conduct the heat away. ANIMAL HEAT. 79 What keeps the temperature of the body uniform ? The circulation of the blood, which distributes the heat very evenly. What conditions of the vasomotor system influence the distribution of heat ? Local dilatations of the bloodvessels produce increased tempera- ture of the part and increased heat dissipation, and, indirectly, increased local heat production. What is the function of the perspiration in regard to bodily heat ? By its evaporation it aids enormously in the dissipation of heat when heat is formed in or added to the body too rapidly. Why can a person stand a high heat in a dry atmosphere better than in a moist atmosphere ? Because in a dry atmosphere the perspiration is evaporated so rapidly that the heat is readily dissipated. How high a temperature may the human being stand in an absolutely dry atmosphere ? According to Blagden, a temperature of 198° to 211° F. was supported in dry air for several moments, and on one occasion he stood 260° F. for eight minutes, having trained his skin to exces- sive secretion. Workmen in English iron furnaces sometimes stand on a furnace floor which is red hot and the air of which stands at 350° F. Chabert, the so-called “fire-king,” is said to have stood from 400° to 600° F., according to Morrant Baker. Which one of the animal tissues is the best protector against cold? The fatty layer, which nearly always occurs in varying amounts under the skin in all warm-blooded animals, and forms a protective covering whereby the conduction of internal heat is almost im- possible. Fibrous tissues conduct heat more readily in the direction of their fibres than at right angles. The bones are the next best con- ductors of heat, and are followed by blood-clots. The spleen, liver, 80 ESSENTIALS OF HUMAN PHYSIOLOGY. cartilage, tendon, muscle and elastic tissue, and nails follow as conductors of heat. The skin is a poor conductor of heat. What influence has starvation on the bodily temperature ? It lowers it greatly. What effect has sleep and hemorrhage on temperature ? In those persons who sleep during the day and work at night the typical course of the temperature is inverted from that which has been already stated as normal. Hemorrhage causes at first a slight fall in temperature, and after that a rise of several tenths of a degree, which is curiously usually associated with a chill or slight rigor. Several days after this the temperature falls again. What is the cause of the fall of temperature after hemor- rhage ? The interference with oxidation. What effect has the artificial cooling of animals ? It produces great depression, but voluntary and reflex movements are not abolished. The pulse falls from 100 to 150 to 20 beats per minute, the blood pressure falls, the respirations become shallow, and death occurs with spasms and signs of asphyxia. What is the asphyxia due to ? Failure of respiration: for if artificial respiration be employed at this time the temperature rises fifteen to twenty degrees. Lan- dois asserted that if in addition to artificial respiration external Warmth be applied, animals apparently dead for forty minutes can be resuscitated. What is hibernation ? A condition in which an animal has all its vital processes temporarily in abeyance. Respiratory and intestinal movements cease completely and the cardio-pneumatic movements alone sustain the slight exchange of oxygen in the lungs. If a warm- blooded animal be cooled to 30° F., it wakes before freezing. Varnishing the skin of an animal increases heat dissipation so enormously that death occurs, which is put aside if external heat be applied. THE KIDNEYS. 81 THE KIDNEYS. What are the kidneys? Compound tubular glands. What is the function of the kidneys ? Their function is the secretion of urine. What is the purpose of the large amount of fat around these organs ? It acts as a protective. What is the size of the adult kidney ? About four and four-tenths of an inch long, three inches thick, and two inches wide. In the male it weighs from four to six ounces, in the female from four to five and a half ounces. Of what two portions is the kidney made up ? The parenchyma, consisting of the outer or cortical layer, and the inner or medullary layer. The medullary layer is also some- times called the pyramidal portion. Into what two divisions is the medullary portion divided? It is subdivided into the boundary layer of Ludwig and the papillary portion. What appearance has the cortical portion of the kidney when torn ? It presents a granular aspect, due to the presence of the Mal- pighian corpuscles. Striae are also seen, due to the medullary rays. What is the difference between the boundary zone or layer of Ludwig, and the papillary portion of the kidney ? The boundary zone is darker, and often purplish in color, while the papillary zone is nearly white, and uniformly striated. The striae merge into the apex of the pyramid. Which is the least pliable, the cortex or medullary portion? The medulla of the kidney is less pliable than the cortex. This 82 ESSENTIALS OF HUMAN PHYSIOLOGY. is due to the greater amount of connective tissue, and the bundles of straight tubes which may be traced at regular intervals, running upward, and becoming smaller and smaller as they pass toward the periphery. Fig. 12. Longitudinal section through the kidney (after Tyson and Henle). 1. Cortex. 1'. Medullary rays. 1". Labyrinth. 2. Medulla. 2'. Papillary portion of medulla. 2". Boundary layer of medulla. 3. Transverse section of tubules in the boundary layer. 4. Fat of renal sinus. 5. Artery. * Transverse medullary rays. A. Branch of renal artery. C. Renal calyx. U Ureter. In what portion of the kidney is the labyrinth ? That portion of the cortex which occurs between the medullary rays is called the labyrinth, owing to the arrangement of its tubules. THE KIDNEYS. 83 How many pyramids have we in each kidney ? Usually about eight or twelve. The pyramids are sometimes called those of Malpighi or Ferrein. The apices of the pyramids are directed toward the pelvis of the kidney, while their bases are directed toward the cortex, and each one of them opens into a small saccule or calyx, which in turn forms with others a dilated pouch, situated at the pelvis of the kidney, forming the beginning of the ureter. How many times do we have the pelvis of the kidney divided ? First, into two or three divisions, and then again into eight or twelve smaller ones, which are called calyces. What is the function of a calyx ? It receives the point of one pyramid, generally, but sometimes two pyramids empty into one calyx. What do you mean by the tubuli uriniferi ? Fine, very elongated tubes, composed of a nearly homogeneous membrane, and lined by epithelium possessing the power of secre- tion. These tubes are, on the average, one six-hundredth of an inch in diameter. They begin at the Malpighian corpuscle in the cortical portion of the kidney, and, after passing through many convolutions, finally end in the pyramidal bodies, from the papilla- like point of which the urine drops into the saccules already men- tioned. In what portion of the kidney do we find the tubuli uriniferi ? Both in the medullary and cortical portions. Into how many divisions are they divided? Fifteen. Is there any difference in the function of each division ? Certain sections are supposed to secrete certain substances. What is the glomerulus or Malpighian body ? It is composed of a small tuft of bloodvessels covered with a 84 ESSENTIALS OF HUMAN PHYSIOLOGY. layer of cells and surrounded by a membranous covering, known as Bowman’s capsule, which is the beginning or dilated extremity Fig. 13. Subcapsular layer without Malpighian corpuscles. > Cortex. Inner stratum of cortex, without Malpighian corpuscles. Diagram of two uriniferous tubules. (Tyson and Brunton, after Klein and Noble Smith.) 1. Malpighian tuft surrounded by Bowman’s capsule. 2. Constriction, or neck. 3. Proximal convoluted tubule. 4. Spinal tubule. 5. Descending limb of Henle’s loop. 6. Henle’s loop. 7 and 8. Ascending limb of Henle’s loop. 9. Wavy part of ascending limb of Henle’s loop. 10. Irregular tubule. 11. Distal convoluted tubule. 12. First part of collecting tube. 13 and 14. Straight part of collecting tube. 15. Excretory ducts of Bellini. of the uriniferous tubule. They are apparent to the naked eye, in the cortical portion of the kidney, as little red points. Their average diameter is T|tfth of an inch. What is the function of the glomerulus or Malpighian tuft or corpuscles ? According to most physiologists, the Malpighian tuft secretes the THE KIDNEYS. 85 liquids and salts of the urine, while the epithelial lining of the uriniferous tubules secretes urea and uric acid, or any substance which taken into the body is eliminated by the kidneys. Fig. 14. Bowman’s capsule and glomerulus (after Landois). a. Vas afferens. e. Vas efferens. c. Capillary network of the cortex, k. Endothelial structure of the capsule, h. Origin of convoluted tubule. What peculiar arrangement have we in the blood supply of the Malpighian tuft ? The blood passes, by means of the afferent vessel or artery, to the Malpighian tuft and enters it, giving off immediately a capillary network. At the other side of this capillary network a vessel goes off, which, as a general rule, does not leave the Malpighian body on the opposite side from the entrance of the artery, but finds its exit from the same opening as that by which the artery entered. The uriniferous tubule, however, is given off from the Malpighian body on the opposite side from that at which the artery enters and the efferent vessel leaves. The capsule of Bowman, or the beginning of the uriniferous tubule, may be considered as a sac, into which is secreted the liquid by the Malpighian tuft. Is the efferent vessel called a vein ? The efferent vessel after leaving the Malpighian body forms a 86 ESSENTIALS OF HUMAN PHYSIOLOGY. second capillary network, twisting around the uriniferous tubules. Not until these capillaries come together do they form one vessel, known as the vein. Why is the efferent vessel smaller than the artery ? It is somewhat smaller for the reason that it loses some of its liquid in the Malpighian body. What other vessels have we ? Besides the efferent and afferent vessels, we have those known as the vasa recta, which, instead of being concerned in any way with the Malpighian tufts, pass directly out of the kidney, through the medullary portion. Fig. 15. Longitudinal section of kidney (after Ludwig and Tyson). PF. Pyramids of Ferrein. RA. Branch of renal artery. RY. Lumen of renal vein receiving an interlobular vein. VR. Vasa recta. PA. Apex of a renal papilla, b, b, embrace the bases of the renal lobules. THE KIDNEYS. 87 What is their function ? Their function is to afford a side stream for the blood in cases of congestion, so that all of it will not of necessity pass to the paren- chyma of the organ. What other vessels carry on a side stream ? Another side stream, which is less important, but for the same purpose, is produced by the fine interlobular arteries which, as they approach the surface of the kidney, communicate with the capillaries of the external capsule. In what way is the kidney nourished ? By bloodvessels which dip down from the capsule, and from the vasa recta. What are the nerves of the kidney ? They are derived from the renal plexus and the lesser splanch- nics. Do these nerves govern secretion, or only the blood supply? We know that they govern blood supply, but it is not proven that they influence secretion. What effect has increased blood pressure on the urinary secretion ? According to most of the text-books, increased blood pressure increases urinary flow, and vice versa; but recent investigations have seemed to prove that blood pressure has no very great influ- ence over the kidney. The urine which is increased by pressure, contains less solids, proportionately, than urine formed by stimu- lation. “Pressure” urine is scarcely more than a leakage, and not a true secretion. What is the function of the ureters ? To carry the urine from the pelvis of each kidney to the bladder. Do the ureters possess any power of urging on the flow ? Yes; they have a slight peristaltic movement, and are supplied by motor and sensory nerves, the sensory nerves showing their presence in the human being when a calculus is being passed. 88 ESSENTIALS OF HUMAN PHYSIOLOGY. How long does it take the wave of contraction to travel along the ureters from the kidney to the bladder ? About one-tenth of a second. In what way do the ureters enter the bladder ? Obliquely. They enter the external wall of the bladder at one point, pass between its coats for a short distance, and then open on its inner surface. In what way is this opening arranged ? A small papilla with a valve-like action, permits the urine to flow out but not to return, and the oblique manner in which the ureter enters the bladder forms a sharp bend in that tube which acts as a valve, particularly when the bladder is distended. What mechanical arrangement have we to prevent leakage from the bladder ? At the neck of the bladder the circular muscular fibres are strongly developed, and act as a sphincter, and in addition to this is the muscle known as the sphincter of the urethra, which also acts in very much the same way. Remember! Both these muscles must relax before urination can take place. What is the function of the bladder? To retain the urine until a sufficient quantity has been collected to pass, in order that a constant dribble may not take place. What is its capacity ? About one pint. In what condition is the mucous membrane of the bladder when the bladder is empty ? It is thrown into rugous folds. What is the cause of the movement of the urine ? First, it is formed under high pressure in the kidney; second, gravity, when the person is erect, aids its passage; and, third, the muscles of the ureter contract rhythmically, and so aid its onward flow. This movement of the ureter is reflex, and is due to the presence of the urine in it. THE KIDNEYS. 89 Do both kidneys act constantly? No ; they act alternately. What influence has the ingestion of small or large quantic ties of water on the urinary flow ? During thirst it amounts to but two or three drops every minute, when drinking it often runs in a steady stream. In what way is the urine discharged from the bladder ? By contraction of its muscular coats, which, it will be remem- bered, run in all directions. What muscles aid in the voluntary act of urination ? The respiratory muscles and abdominal muscles. The diaphragm is fixed, and the act is completed by the accelerator urinae muscle, which quickens the stream. In what portion of the spinal cord is the centre for the bladder ? In the lumbar region. What other muscle aids in the expulsion of the last drops of urine, other than the accelerator urinae ? The bulbo-cavernosus. What is the nervous mechanism of urination ? The sphincter vesicae is kept in a state of contraction by the motor centre governing it in the cord. When the urine collects in the bladder a sensory impulse travels to the cord and brain, and the brain and cord in turn send down motor impulses which contract the muscular walls of the bladder, while a second impulse relaxes the sphincters. Where is the spinal centre for urination situated ? About the point of origin of the third, fourth, and fifth sacral nerves. 90 ESSENTIALS OF HUMAN PHYSIOLOGY. THE URINE. How much urine is secreted in twenty-four hours ? About three pints in the normal adult. At what time of the day does the minimum secretion take place? Between 2 and 4 A. m. At what time of the day does the maximum secretion take place? Between 2 and 4 p. m. What are some of the causes that diminish the quantity of urine ? It is diminished by increase in the sweat, diarrhoea, thirst, non- nitrogenous food, diminution of blood-pressure, and certain dis- eases. What are the causes which increase its quantity ? It is increased by increased blood-pressure, by copious drinking, by exposure to cold, by the use of nitrogenous food, and various conditions of the nervous system. Various drugs also influence the quantity. What is the specific gravity of the urine? It varies from 1.005 to 1.015 to 1.025. The minimum specific gravity occurs after copious drinking and may be 1.002; the maxi- mum after profuse sweating, and may be 1.040. The mean specific gravity is 1.020. What ready, hut not strictly accurate, method have we for determining the amount of solids in a given specimen of urine ? By the use of Christison’s formula, which consists in multiplying the last two figures of the specific gravity by 2.33, which will give the amount of solids in one thousand cubic centimetres. THE URINE. 91 What is the color of the urine due to ? The color depends on the matters present in it, chiefly uro- chrome and urobilin, a derivative of hematin. The color varies greatly, but the difference in intensity is chiefly governed by the quantity of water which is present. What is the cause of the slight cloudiness which appears in the bottom of a vessel in which urine is placed for a length of time ? It is due to mucus, which is chiefly derived from the bladder. What is the taste and odor of urine ? Its taste is slightly alkaline or bitter; its odor characteristic and aromatic. The odor, however, is altered by various causes, par- ticularly by the administration of drugs. What is the reaction of the urine ? It is acid, owing to the presence of acid phosphate of soda. After standing for a while the acidity is increased, due to fer- mentation of the mucus and other similar products, and, at the same time, with this increase in acidity, urates and free uric acid are deposited. Under what circumstances outside the body does the reaction become alkaline ? After it has become acid it changes to an alkaline reaction, owing to the presence of ammonium carbonate derived from alterations of the urea. At the same time, a strong ammoniacal odor is noticeable, and fetor, with deposits of triple phosphates and alkaline urates, appears. Does the reaction of the urine vary in different animals ? In most herbivora it is alkaline and turbid, but this difference depends not upon a different mode of secretion, but upon the variety of diet. Into what three forms is the urine passed at different times divided ? Urina potus, urina cibi, and urina sanguinis. 92 ESSENTIALS OF HUMAN PHYSIOLOGY. What is the difference between each one of these ? Urina potus is secreted immediately after drinking, urina cibi after a solid meal, and urina sanguinis is that which is secreted early in the morning when neither food nor drink has been ingested. What is the chief solid of the urine ? Urea is the chief solid constituent, and it is the most important ingredient since it is the substance by which the nitrogen of de- composed tissue is given off. What is the result when this urea is not freely eliminated from the body? It produces the condition known as uraemia, in which the patient has convulsions and low muttering delirium ending in death. Does urea exist in a state of solution, or in a solid form in the urine ? In a state of solution. What is its appearance in the solid state? It forms delicate, silvery acicular crystals. What is the quantity of urea excreted in twenty-four hours ? About five hundred grains. Is the quantity of urea per day influenced by diet ? Yes. Nitrogenous or animal foods increase the urea, while a purely vegetable diet decreases it. Is there any difference in the amount secreted by males and females ? Males secrete more than females, while middle-aged persons secrete more of it than the very young or old. Remember, however, that children secrete more in proportion to their weight than do grown persons. What is the origin of urea ? It is derived from two sources: first, portions of unassimilated elements of nitrogenous food; second, from the breaking down of tissue, or tissue waste. THE URINE. 93 Does urea exist, to a certain extent, preformed in the blood, or do the kidneys manufacture it from the blood ? Some of it certainly exists ready formed, the kidneys merely extracting it. What is uric acid? An acid which appears, as a general rule, in small quantities in the urine of the human being, and which is entirely absent in the cat tribe. The quantity of it varies greatly in different animals. In birds and serpents its amount greatly exceeds that of the urea. In what way is the quantity of uric acid increased? By nitrogenous food, but decreased by vegetable food. In gout it is deposited around the joints as the urate of soda. From what does uric acid arise ? From the destruction of albuminous matters. The relation between urea and uric acid is not well understood. What is hippuric acid ? It is found in man and is allied to benzoic acid. Benzoic acid is eliminated as hippuric acid. What are extractives of the urine ? They consist of kreatin and kreatinin, two crystallizable sub- stances derived from muscle metamorphosis. What are the saline matters of the urine ? H2SO4 in the urine forms a compound chiefly or entirely with soda or potash, thereby forming salts. The phosphoric acid also combines and forms salts. The breaking down of what tissues increases the amount of phosphates in the urine ? The nervous tissues. How are the chlorides formed? The chlorine combines with ammonia and potash to form chlo- rides. 94 ESSENTIALS OF HUMAN PHYSIOLOGY. Do gases exist in large quantities in normal urine ? No; in very small quantities. They are chiefly COa and nitrogen. What pathological conditions of the urine occur ? Albuminuria is a condition in which a certain amount of albu- men is allowed to escape from the system by the kidneys. At one time the presence of albumen in the urine was considered to be pathognomonic of Bright’s disease, but it has been proved that it may exist physiologically for a short time after the ingestion of large quantities of albumen. Hematuria is a condition in which there is blood in the urine, the blood coming from the kidney or any portion of the urinary apparatus. What is haemoglobinuria? A condition in which free hsemoglobin occurs in the urine. Remember, that hsemoglobinuria is not haematuria. What is choluria? The presence of bile in the urine. It occurs in certain condi- tions in which the circulation of the portal vein is disordered, or after the ingestion of certain poisons, as, for example, phosphorus. What is glycosuria ? Glycosuria is the presence of sugar in the urine. It is termed diabetes mellitus. What is the cause of diabetes mellitus? It is either produced by a lesion occurring in the diabetic centre in the floor of the fourth ventricle, or is due to disorder of the circulation of the liver whereby the sugars ingested and manufac- tured in this organ are improperly distributed. What is chyluria ? It is a condition in which the chyle from the digestive tract is passed out in the urine. What is diabetes insipidus ? A condition in which a very large quantity of liquid, of a low specific gravity and containing no sugar, is passed. THE SKIN. 95 THE SKIN. What are the chief functions of the skin? It acts as an external integument for the protection of the deeper tissues, as a sensitive organ in the exercise of touch, as an important excretory and absorbing organ, and plays a highly important part in the regulation of the bodily temperature. Of what does the skin consist? The skin consists of a layer of vascular tissue named the corium, derma, or cutis vera, covered by a layer known as the cuticle or epidermis. Underneath and within the corium are embedded several organs with special functions, as follows: the sudoriferous glands, the sebaceous glands, and the hair follicles, while on its surface are sensitive papillae. Are the appendages of the skin, known as the hair and nails, formed from the corium or the epidermis ? They are modifications of the epidermis. What layer of the epidermis contains the pigment in colored races ? The layer known as the rete mucosum. From what portion of the skin does the papillae arise? They are conical elevations of the corium or true skin. What is the function of the papillae ? Nearly every one of them contains a nerve ending, thereby increasing the peripheral sensibility. (For the corpuscles of touch, etc., see the Special Senses, “Touch.”) What is the function of the cuticle? It protects the papillae from injury and forms a check on undue evaporation from the skin. The manner in which it protects sensibility is made evident when we remember the tenderness of those areas, where, by constant rubbing, the epidermis is rubbed off. 96 ESSENTIALS OF HUMAN PHYSIOLOGY. What is the function of the sudoriferous glands ? They pour out the sweat on the surface of the body through ducts which at first are spiral but which, as they approach the surface, become straight. Are the sudoriferous glands the glands which secrete the familiar odors in the axilla and elsewhere ? No; the glands which are odoriferous are like them save that they are larger and have very short, straight ducts. What is the difference between sweat and perspiration? Sweat is applied to the liquid which is secreted so fast that it collects in drops; perspiration, to the moisture which is continu- ously and unconsciously given off by the skin. What is the function of sweat and perspiration ? They aid in the dissipation of heat by their evaporation and thereby reduce the bodily temperature. How much watery vapor is excreted by the skin in twenty- four hours? From one and one-half to two pints. How much C02 is lost in this manner per day ? An amount which is almost to of the amount exhaled by the lungs, and which differs enormously according to the condi- tions surrounding the individual, and exercise, food, and drink. What other impurities are given off by the skin other than CO., ? Urea and inorganic salts. Is the excretory function of the skin important? Exceedingly so, if interfered with it may produce death by throwing too great a strain on the kidneys, for remember that the skin is a supplementary organ to the kidneys. In what ways may the flow of perspiration be increased other than by exercise or exposure to heat ? If a localized vaso-motor palsy occurs sweating sometimes takes THE SKIN. 97 place; section of the cervical sympathetic produces copious sweat- ing of that side of the head. What are the objects of the sebaceous glands ? They secrete a lubricating fluid or oily matter which keeps the skin soft and pliable. What is the vernix caseosa? That sebaceous matter which covers the skin during intra-uterine life. What is the function of hair? It acts as a protection from cold, as when on the head, and pro- tects the skin from friction in the axilla or on the pubis. Besides protecting the head from changes in temperature, it wards off blows which might otherwise be serious in their results to the more vital tissues. What is the function of the nails ? To protect the ends of the fingers from injury or the sensory papillje of the finger tips from contact with harsh, rough objects, which, if it occurred constantly, might deprive them of their deli- cacy of touch. Can absorption of certain substances take place rapidly through the skin? Very rapidly. A familiar example of this is the ptyalism pro- duced by mercurial inunctions. SECRETION. What is secretion ? The separation from the blood of some product, directly or indi- rectly, by the vital process peculiar to a gland or membrane. This product is called an excretion when it is passed out of the body as waste, or a secretion when it carries out some function in the animal economy. Give a good example of an excreting gland? The kidnev. 98 ESSENTIALS OF HUMAN PHYSIOLOGY. Give an example of a secreting gland. The pancreas or mammary gland? (For the manner in which secretion is carried on in each gland, see questions on each subject.) THE MAMMARY GLANDS. What changes take place in the mammary gland during gestation ? It becomes much larger, the areola around the nipple increases in width and deepens in color, the veins become more prominent, while the lobules can be plainly felt. How many lobes has the mammary gland? From fifteen to twenty, each one of which is divided into several lobules made up of acini. What is the function of the lactiferous ducts ? They carry the secretion to the nipple, on which they open by a number of orifices. Just before they enter the nipple they dilate, forming little sacs which collect the milk. In what way are the fat globules of milk formed? They are supposed to be the results of a physiological fatty degeneration of the cells lining the acini and ducts. (For Milk, see Articles used as Foods.) THE BODILY METABOLISM. What do you mean by the term Bodily Metabolism? Those phenomena by which all living organisms are capable of taking substances derived from their food into their tissues, and making them an integral part of their own bodies ; further than this, metabolism includes the breaking down of these tissues, and the removal of the results of their destruction; the first half of the process is termed assimilation, the second half excretion. MILK. 99 Does the body merely assimilate sufficient food to replace exactly those particles which are destroyed, or does it do more than this, and act as a storehouse, from which, on a sudden strain, energy may be derived ? It acts as a storehouse of potential energy, which, when necessity arises, it may transform into kinetic energy. What do you mean by potential energy? That energy which possesses the power to move, but is quiescent. What do you mean by the term kinetic energy ? Potential energy, when exerting its influence, either by pro- ducing motion or preventing it, is called kinetic energy ; in other words, potential energy is latent, kinetic energy is active. A coiled watch-spring held firmly represents potential energy, but if the pressure is removed, its force is transformed into kinetic energy. GENERAL VIEW OF THE MOST IMPORTANT SUBSTANCES USED AS FOOD. How much of the body is made up of water ? 58.5 per cent, of the body consists of water, which is continually taken in and given off. What is the purpose of water in the organism ? The processes of digestion and absorption require the presence of water for the solution of the food, and it is also used to carry off the effete products. So much water exists in the tissues of all animals that Hoppe-Seyler has put it that all organisms live in water. Milk. What is the use of milk and its preparations ? Milk forms a complete typical food, in which are all the con- stituents necessary for life and growth. 100 ESSENTIALS OF HUMAN PHYSIOLOGY. What are the constituents of milk ? In every ten parts of proteids we have ten parts of fats and twenty parts of sugar. Describe some of the characters of milk. It is an opaque, bluish-white liquid, with a sweetish taste and a characteristic odor. What is this odor due to ? Probably to the peculiar volatile aromatic substances derived from the cutaneous secretion of the glands. What is its specific gravity ? 1.026 to 1.035. What is the reaction of human milk ? It is always alkaline; cows’ milk may be alkaline, sometimes acid, or even neutral. The milk of carnivora is always acid. What are milk globules ? Small, highly refractive, oil globules floating in a clear fluid, the milk plasma. The white color of milk is due to their presence. Of what do the globules consist ? Of fat or butter, surrounded by a coating of casein. What is the effect of churning on these milk globules ? This coating of casein is broken, and the butter globules are allowed to run together. What does the milk plasma contain aside from the globules? It contains free casein, serum-albumin, and, to a less extent, a body resembling albumin, the lacto-protein of Millon and Lieber- mann. What other substances have we in milk ? Galactin, albuminose, and globulin; very minute traces of pep- tone are also present. Milk sugar, a carbohydrate resembling dextrin, and urea and extractives complete the list of its con- stituents. Remember, that the casein is the albuminous portion MILK. 101 of milk while the butter globules make up the hydro-carbon portion. When milk is boiled, what changes take place in it ? The serum-albumin coagulates, while the surface also becomes covered with a layer of casein which has become insoluble. Is raw or boiled milk most digestible ? The raw milk; if nature had intended that boiled milk should be more digestible than raw milk, raw milk would have been formed with the same conditions present that exist in boiled milk. Upon what does the coagulation of milk depend ? Upon the coagulation of its casein. What salt in milk keeps the casein in solution ? Calcium phosphate; which is, of course, destroyed by the acid of the stomach. Remember, that milk coagulates in the stomach, not on account of the acid, but owing to the presence of a milk- curdling ferment. (See page 63, Digestion.) What causes the spontaneous coagulation or souring of milk? It is produced by the development of lactic acid, which is formed from the milk sugar by the action of the bacterium lacticum. What is the difference between human milk and cow’s milk ? It contains less albumin, and the albumin it does contain is more soluble than that in cow’s milk. It also contains more sugar and fats than does cow’s milk. What is colostrum ? It is the substance which is secreted at the beginning of lacta- tion, and contains much serum-albumin, and very little casein, while all the other substances, specially the fats, occur in large amount. What is the purpose of colostrum? Containing, as it does, a large amount of fat, it acts as a purga- tive, and sweeps out the meconium and other effete products from the alimentary canal of the infant. 102 ESSENTIALS OF HUMAN PHYSIOLOGY. Are gases found in ordinary milk ? Only in minute traces. What salts are found in milk? The potash salts are much more plentiful than the soda salts; there is also a large amount of calcium phosphate present. What is the purpose of the calcium phosphate? It is necessary in the formation of the bones of the infant. What difference is there in the composition of milk at various times? That drawn last is always richer in butter, while if the ducts are emptied frequently the butter decreases but the casein increases. Are eggs a typically complete food ? They are not as complete a food as is milk, but are the most typical food next to milk. What is the object attained by cooking flesh? It breaks up to a certain extent the elastic coverings of the muscular fibre, softens the connective tissues, and renders it more tender and easy of digestion. In the vegetable foods, what are the chief nitrogenous substances? Gluten is the most abundant nitrogenous substance present, and occurs immediately under the husk. How many groups of foods are necessary for the main- tenance of health in man? Five. What substances make up these groups ? First, the starches, which are used for the purpose of adding heat to the body, and also fat; second, the fats, which are used for the purpose of maintaining the bodily heat and retaining it; third, albuminous foods, whose function is to add force to the system; fourth, water, which is necessary for the carrying out of the vital processes; and fifth, salts, which are also absolutely needful for the maintenance of health. MILK. 103 What is the absolute amount of the different food-stuffs required by an adult in twenty-four hours? It varies enormously according to the surrounding conditions, but, as a general rule, it should contain 130 grammes of proteids, 84 grammes of fats, and 404 grammes of carbohydrates. Remember, that the carbohydrates should always be greatly in excess of the nitrogenous principles. What effect has the withdrawal of all forms of food-stuffs, with the exception of one particular class, upon nutrition? The animal wastes, and finally dies with very much the same symptoms as would follow starvation. The manner in which effete products are taken up and excreted has already been considered (see Circulation, Respiration, and the Kidney and Urine). What process goes on during starvation ? All food being taken away from the body the organism is re- quired to abstract at first the unimportant tissues in order to keep up its vital processes. After this the wasting becomes marked, and the bodily weight falls. Weakness, the result of the breaking down of vital tissues, comes on, and finally death, after all sub- stances capable of supplying force in the body have been used up, save those actually concerned in the vital processes. How long will the average adult survive without food? About twenty-one to twenty-four days, although cases are on record of survival for forty-one days. How much bodily weight is lost before death? Four-tenths of the bodily weight. Are fats ever formed from proteids ? Yes; as an example of this, the cow does not consume as much fat in a day as she gives in butter. 104 ESSENTIALS OF HUMAN PHYSIOLOGY. THE MUSCLES.1 What is the function of the muscles'? To produce movements, which vary according to the rapidity and power of their contraction. In what way do the voluntary muscles act upon the hones? As levers. They are often attached to the short arm of the lever, and while this is apparently a disadvantage, since under these circumstances greater force is required to lift a given weight, it, in reality, is of the greatest service, since slight contractions of muscles cause very extensive and rapid movements of the part. How many orders of levers are met with in the movements of the different bones of the skeleton by the muscles ? All three; and in some cases all three occur at the same joint. Give an example of the first order of levers. When the triceps is the power which draws upon the olecranon, thus moving the hand and forearm around the trochlea, which acts as the fulcrum. Give an example of the second order. This occurs when the hand, resting on a point of support, acts as the fulcrum, and the triceps pulling on the olecranon is the power which raises the humerus, upon which is fixed the body or weight. Give an example of the third order. This is exemplified by the action of the biceps in ordinary flexion of the elbow, in which the biceps is attached to the upper portion of the forearm. What two varieties of muscular fibre have we ? Two; striped, or striated or voluntary ; unstriped, unstriated or involuntary. The first group are moved entirely by the will-power, or by centres under the control of the will-power. The second group, solely by nervous centres over which the will-power has no direct influence. 1 The anatomy of muscles is to be found in anatomical text-books. THE MUSCLES. 105 What large mass of striped muscular fibre is an exception to this rule? The heart, which, although it is made up of striped muscle, beats independently of the will. The arrangement of the heart muscle, however, is somewhat different from striped muscular fibres else- where. What is the difference in the contraction of striped and unstriped muscular fibre? The striped muscular fibre usually contracts more rapidly. What is the consistency of muscle ? The contractile substance of muscle is so soft as to be almost fluid, being of the consistency of jelly. What is the chemical composition of muscle ? As already pointed out elsewhere, it is impossible to determine this during life, since the analysis produces death. Muscle, how- ever, contains the substances known as muscle-serum and muscle-clot or myosin, which are the result of certain chemical changes occur- ring after death. What effect has coagulation of the myosin in muscle ? Its formation is followed by “rigor mortis,” or post-mortem rigidity. In what way can this coagulation be postponed? By keeping the muscle at a temperature but a few degrees above freezing point. If a muscle be kept in this manner, pressure will cause the exudation from it of a yellow, opalescent, alkaline juice, which on still further cooling changes into a jelly. What effect has warming of this jelly ? It passes through the stages of coagulation seen in ordinary muscle after death, producing the same fluid serum and muscle-clot or myosin. What is this muscle juice sometimes called? Muscle plasma, which is supposed to be the contractile matter in living muscle. 106 ESSENTIALS OF HUMAN PHYSIOLOGY. What does the coagulation of muscle plasma very closely resemble ? The coagulation of blood plasma, with the difference that the muscle clot is gelatinous and not in threads, as is fibrin. It is a globulin, and is soluble in a two per cent, solution of common salt. Remember, that this globulin forms the greater portion of albu- minous matter in muscle. What is the difference between the reaction of muscles before and after death ? Before death they are alkaline; after death, acid. Of what does the serum of the muscle consist beside the albuminous principles ? 1st, kreatin, kreatinin, and xanthin; 2d, haemoglobin; 3d, grape sugar, muscle sugar or inosit, and glycogen ; 4th, sarcolactic acid, made from the inosit by fermentation; 5th, carbonic acid; 6th, potassium salts; and, 7th, 75 per cent, of water. What do you mean by the elasticity of muscle ? The degree to which the muscle can be stretched and still return to its normal length. If a given weight be applied to the end of a muscle, it is stretched a certain distance; but an additional weight or weights do not produce by any means an elongation equal to the first. The elongation, on additional strain, is con- stantly decreased in extent. Is there any variation in the elasticity of muscles? At first a strain on a muscle produces very rapid extension; but this is constantly decreased as time goes on, finally ceasing. Muscles which are fatigued are more readily stretched than fresh ones. What difference is there between the elasticity of dead and living muscle ? Dead muscle possesses less elasticity and requires a greater weight to stretch it. It can be stretched further than living muscle, but does not return to its former length as completely as the normal muscle. THE MUSCLES. 107 Are the muscles of the body always on the stretch, and if so, what is the object reached by this condition? They are always on the stretch, even when passive, and act as ligaments which bind together, in a compact mass, the entire body. Muscles nearly always have opposing muscles whose function it is when exercised, to produce opposite movements. The elasticity of these muscles, in a passive state, also opposes active contraction in the opposite muscle, which is, however, easily overcome. After the active contraction has taken place, the elasticity of the passive muscle acts as a weak spring, thereby keeping up the tonicity of the limb and preventing sudden jerkings of the body, as would occur if a muscle should contract suddenly and “ take up the slack” in the opposite muscle. What electrical phenomena have we in muscle ? In the normal living muscle we have invariably present an electric current known as the natural muscle current. What circumstances influence this current ? It is greatly reduced by fatigue and loss of vital power, and is generally supposed to be absent in perfectly normal passive muscle lying in situ. As soon as the muscle is moved or disturbed by partial removal from the body the current develops. What do you mean by “negative variation” in muscle? If a muscle be connected with a galvanometer so as to measure its natural current and then be stimulated to a contraction by means of the nerve trunks, a marked decrease occurs in the current. The galvanometric needle swings toward the zero point, showing that the current is weakened and destroyed. This is called the negative variation, and precedes the change to an active condition of the muscle. What do you mean by the irritability of the muscle ? The capability with which a muscle passes into contraction. What are the usual causes of contraction of the voluntary muscles ? They contract ordinarily in response to impulses communicated 108 ESSENTIALS OF HUMAN PHYSIOLOGY. to them by nerves, the impulse originating in the brain or spinal cord. The will power is the most common cause of contraction of the skeletal muscles. What other conditions may produce contractions of the muscles ? Contraction of the muscles may be produced either by the appli- cation to them directly of some irritating or stimulating substance, or by the application of stimulation to their supplying nerves. Is it possible to cause contraction in muscular fibre which is devoid of terminal nerve filaments, or, in other words, does the contraction of a muscle necessarily depend upon the presence of peripheral motor nerves ? That muscles may be stimulated to contraction without the in- tervention of nerve fibres, is proved by the fact that some parts of muscles, as the lower end of the sartorius, respond energetically to all forms of muscle stimuli, though they possess no nerve endings; there are some substances, too, which produce contrac- tion of muscles on direct application, which will not produce that contraction when applied to the nerve trunk, as, for example, ammonia. Again, the muscles will generally respond to various stimuli long after the nerve supplying them has been killed by exposure, and curare, which paralyzes the peripheral ends of the motor nerves in the muscles, in no way prevents the contraction of the muscle itself when it is directly stimulated. What forms of muscle stimuli have we ? First, mechanical stimulation, as by a sudden blow or pinch, resulting in momentary transient contraction. Second, thermic stimulation. Contraction of the muscle takes place if the tem- perature be raised or lowered. This contraction, however, is scarcely identical with ordinary muscular contractions, since it is a prolonged spastic contraction of an abnormal type. Third, chemical stimulation, which may produce contractions by irri- tating mineral and organic acids, various metallic and neutral salts. Fourth, electrical stimulation, which is the most common form employed, and gives the most satisfactory results. THE MUSCLES. 109 At what time during the application of an electrical current to a muscle does the contraction take place ? Remember that it takes place not while the current is passing through the muscle, but at the moment the current is turned on or turned off, or is suddenly increased or decreased in strength. A constant current of exactly even intensity may be made to pass through a muscle without exciting contraction. Is the stimulus necessary to produce contraction in a muscle when applied to its nerve trunk, sufficient to pro- duce the same degree of contraction in the muscle when applied to the muscle itself? No, it is not. What are the chemical changes resulting in a muscle during its contraction? Its neutral or faintly alkaline reaction becomes for the moment acid, owing to the formation of sarco-lactic acid. More oxygen is taken up from the blood than when the muscle is at rest. A greater amount of carbon dioxide is given off, but the change in the quantity of CO2 has no exact relation to the quantity of oxygen used. A diminution is said to occur in the glycogen of muscle, and a peculiar muscle sugar makes its appearance. What changes occur in the elasticity of the muscle during contraction? The elasticity is less than when it is in a passive state—that is, a given weight will stretch a contracted muscle more than a passive muscle, but the return to the normal length of the muscle is not so complete, or, in other words, extensibility is increased, elasticity is decreased. What effect, therefore, has stimulation of a muscle which is overloaded by a weight greater than it can lift ? When stimulation is applied to such a muscle we get elongation instead of contraction, because of the rule just now given, namely, that the active state lessens the elastic power of the muscle. 110 ESSENTIALS OF HUMAN PHYSIOLOGY. What effect has stimulation of one part of a muscle upon the rest of the muscle ? A contraction wave passes from the part stimulated over the whole mass. What effect has the activity of muscle fibre upon its temperature ? It raises it very markedly, the production of heat being in direct proportion to the tension of the muscle. If the muscle be kept in a state of constant activity, so that fatigue is produced, the temperature falls. What change in shape takes place in the muscle on contraction? It shortens, and in direct ratio with its shortening its thickness increases. There is, therefore, but little change in bulk, but con- siderable change in shape. What do you mean by the “latent period” ? The short space of time which elapses between the moment of stimulation of a muscle and the beginning of its contraction. In the voluntary muscle of the frog this lasts only about one-tenth of a second. What do you mean by the period of “rising energy”? The space of time during which contraction occurs first slowly, then more quickly, then more slowly. What do you mean by the term “falling energy”? The period at which relaxation of the muscle takes place. At first slowly, then more quickly, finally, more slowly. Is there any pause at the height of contraction before relaxation begins ? No, none at all. Is there any variation in the rapidity of contraction of different muscles ? Yes, an enormous difference exists not only in various animals, but in the same muscles of a single individual. As an example THE MUSCLES. 111 of the difference in rapidity of contraction in the muscles of dif- ferent animals, may be mentioned the fact that while the unstriped muscular tissue of a mollusc occupies several minutes for its con- traction, the muscle of the wing of a horse-fly contracts 330 times a second. The variation and rapidity of contraction differ very largely with the needs and habits of the animal. What do you mean by the “ maximum contraction ” of a muscle ? The greatest shortening which can be produced by a single in- stantaneous impulse or stimulus. What do you mean by the term “ over-maximal contrac- tion ” ? If the current be increased after the maximum contraction is reached, a second and still further contraction occurs. This is called the over-maximal contraction. What do you mean by the term “ summation ” ? If a muscle be caused to contract by a shock of medium strength, it contracts to its maximum; but if a second shock be given while the muscle is contracting from the first shock, a new maximum contraction is added to that already under way. This is called the summation of effect. What do you mean by the “ tetanus ” ? A condition of a muscle in which it apparently remains in a constant state of contraction—or, in other words, a swwnafe'on of contractions exists. To produce artificial tetanus, impulse after impulse must be transmitted to the muscle with great rapidity, otherwise between each stimulus the muscle will partially relax or attempt to pass into the condition known as falling energy. Upon what does the irritability and fatigue of a muscle depend ? Upon the amount of labor required and the nourishment supplied by the blood. Fatigue means lessened irritability. 112 ESSENTIALS OF HUMAN PHYSIOLOGY. THE NERVOUS SYSTEM. What is the nerve trunk made up of ? First, the primitive fibril, which is the simplest form of nerve filament, and is visible only with a very high power of the micro- scope. Is the primitive fibril the same thing as the axis cylinder ? No; the axis cylinder is made up of bundles of the primitive fibrils held together by a slightly granular element. Give a description of a complete nerve. It is made up of: 1st. The primitive fibril. 2d. The naked axial cylinder. 3d. The clothed axis cylinder, covered by the white substance of Schwann, or the medullary sheath, or the myelin. 4th. The clothed axis cylinder covered by the sheath of Schwann, or the neurilemma. 5th. The clothed axis cylinder with both these coverings, or the complete nerve. What is the difference between the fibres of the cerebro- spinal system and those of the sympathetic system ? Those of the first are formed as the nerves of the 5th group just given, while the sympathetic are made up of axis cylinders covered by the sheath of Schwann, or neurilemma, as in the 4th group. What is the function of Ranvier’s nodes ? They are supposed to permit the diffusion of plasma from outside into the axis cylinder, and thereby to aid the nutrition of the nerve. What are the nervi-nervorum ? They are small nerves which accompany the nerve sheaths, thereby endowing them with sensibility. Give some facts in regard to the chemistry of the nervous substance. Albumin occurs chiefly in the axis cylinder and in the sub- stance of the ganglionic cells. Potash, albumin, and a globulin-like substance are also present. Another substance of the same char- acter is nuclein, which occurs especially in the gray matter, and neuro-keratin, a body resembling keratin and which contains much sulphur. The connective tissue of nerves yields gelatin, but the sheath of Schwann only yields elastin. In addition to these we have cerebrin, lecithin, and protagon. THE NERVOUS SYSTEM. 113 What is the chemical reaction of nervous matter ? When passive it is neutral or feebly alkaline; while active and after death it is acid. What difference is there between the reaction of the ner- vous matter in general and the reaction of the brain ? The gray matter of the brain is supposed to be always acid, while the other is not. Have nerves great or slight tensile strength ? They possess great strength, for it is a well-known fact that in cases where by accident the arm is torn off, the nerve is the only part not ruptured. Tillaux has found that the sciatic nerve will hold a strain of as much as 120 pounds. What is the function of the nervous system ? It is the apparatus by which distant parts of the body are kept in constant relationship with one another so that a change of condition in any one spot is communicated to, and may set up corresponding changes in, remote parts. What two divisions have we of nerve fibres ? The afferent or centripetal, and the efferent or cenZH/ut/aZ; most nerves contain both sets of fibres. Do nerve fibres possess the power of generating force in themselves ? They do not. Neither are they capable of originating impulses; They are functionally inactive until they receive impulses from higher nerve centres. What is the distinction between the white and the gray nerves ? The white nerves contain the white substance of Schwann, the gray nerves do not. Which of these two varieties is the most common ? The white by far, since the gray are contained chiefly in the sympathetic system and parts of the organs of special sense. 114 ESSENTIALS OF HUMAN PHYSIOLOGY. What is the function of an afferent or centripetal nerve ? To carry impulses from the periphery to the centre which may receive them. What is the function of an efferent or centrifugal nerve ? To carry impulses from the centre to the periphery, which impulses may arise of themselves in the central nervous system or be excited reflexly through a sensory nerve. Are impulses travelling along one nerve trunk ever trans- ferred to another nerve trunk running near by ? No, never, under any circumstances, if both nerves are intact. How many divisions have we of efferent nerves ? First, motor, or nerves going to muscles causing them to contract; second, secretory, which call forth the activity of glands; third, inhibitory, which check or prevent some activity; fourth, vaso- motor nerves, which regulate the contraction of the muscular coat of the bloodvessels, and trophic, thermic, and electric nerves, all of which are doubtfully in existence, save the electric, which occur in animals capable of emitting electrical discharges. What do you mean by inter-central nerves ? Inter-central nerves are those which act as bonds of union between the cells of nerve centres. What is the velocity of nerve force ? It is about at the rate of thirty metres per second, or the speed of a fast express train, so that impulses can only travel from one portion of a man’s body to another at about the same rate as an express, or about twice as fast as the fastest horse can gallop. What do you mean by “ negative variation ” ? The natural current of a nerve, like that of a muscle, undergoes a diminution at the moment the nerve is stimulated ; this is termed the negative variation. The negative variation travels along the nerve at just the same velocity as the impulse does from the point of stimulation ; as a consequence of this the negative variation and nerve impulse are believed to be identical. THE NERVOUS SYSTEM. 115 What do you mean by electrotonus ? Electrotonus may be defined as the electrical condition of a nerve, which undergoes constant variation according to the circum- stances affecting it. This will be more clear after the question on anelectrotonus and katelectrotonus has been read. What do you mean by the terms anelectrotonus and katelectrotonus ? Anelectrotonus is the term applied to the condition of the nerve near the anode, or positive pole, during the passage of a constant electrical current, the irritability of the nerve being decreased in this region. Katelectrotonus is applied to the part of the nerve near the cathode, or negative pole, the irritability being here increased. What do you mean by the irritability of nerves ? The condition which permits of the transmission of impulses fi'om more or less powerful stimuli. What conditions are necessary for this irritability ? A perfect supply of blood, to bring nourishment and carry away effete matters, an uninjured connection with the nerve centres, and a normal temperature. What is the result if the blood supply of a nerve is cut off? The nerve rapidly loses its excitability, and finally becomes paralyzed. Supposing a nerve is exhausted by fatigue or lack of blood supply, how does recovery occur ? When a nerve recovers it does so slowly, then more rapidly, and afterward more slowly. At what portion of the nerve trunk would you apply the stimulus to produce the greatest contraction in the tributary muscle, or, in other words, at what point would you find the greatest irritability of the nerve? At some part of the nerve distant from the muscle. The further from the muscle the. more powerful is the contraction produced. The impulse seems to gather force as it goes along the nerve. 116 ESSENTIALS OF HUMAN PHYSIOLOGY What do you mean by the “indifferent point” of a nerve ? As already stated, when a constant current is applied to a nerve its irritability is greater in the neighborhood of the cathode, but is diminished in the neighborhood of the anode. Near the middle of the nerve, or rather a point about half way between each pole, we have an area known as the indifferent point, since at this portion the increased irritability of the cathode no longer exists, nor does the diminished irritability of the anode occur. This indifferent point is not always midway betweeen the two poles, since variations in the strength of the current influence its position. What are the laws of contraction ? 1. In all muscles, when the current is broken, the disappearance of anelectrotonus is the cause of the stimulation. 2. When the current is made it is the appearance of katelectrotonus which causes the stimulation. 3. With the same current the contraction produced with the making of the current is more than the contraction which occurs on the breaking of the current. 4. Anelectrotonus causes reduction of irritability and conductivity. 5. Katelectrotonus causes increase of irritability. 6. With ascending currents, the portion of the nerve next to the muscle is in a state of reduced functional activity or anelectrotonus. 7. With descending cur- rents the part of the nerve next the muscle is in a state of exalted activity—katelectrotonus. 8. These changes are much weaker with weak currents than with strong ones. What do you mean by the term nerve corpuscles or terminals ? Those small nerve bodies or corpuscles in which nerve fibres end and through which efferent nerve fibres give off their impulses and afferent nerve fibres receive their impulses. Those which are attached to the endings of sensory or afferent nerves of the skin are known as tactile corpuscles. PHYSIOLOGY OF THE SPINAL NERVES. 117 PHYSIOLOGY OF THE SPINAL NERVES. It will be remembered that thirty-one pairs of spinal nerves leave the vertebral canal between the vertebrae, in contradistinc- tion to the cranial nerves, which come out from the base of the skull, and that each pair of nerves is attached to the spinal cord by two roots, known as the anterior and posterior, which becoming united pass through the intervertebral canal, forming one trunk*. Just before the junction of the two roots it will also be remember 3d that the posterior root is enlarged by a ganglionic swelling. The spinal nerves are, therefore, sometimes called mixed nerves, for the reason that they contain both efferent and afferent fibres. Those going from the anterior portion of the spinal cord carry the motor or efferent impulses, those coming to the posterior part of the spinal cord carry the afferent impulses. What do you mean by recurrent sensibility ? If after division of a motor root the peripheral portion of it be stimulated some pain is felt. This is due to what is known as recurrent sensibility, and depends on the fact that some of the fibres of the sensory root, after having joined the motor root, instead of going as usual to the periphery, revert and supply the motor root. What is the function of the ganglia which occur on the posterior roots of the spinal nerves ? Their function is not clearly understood. There is no evidence of their being centres of reflex action, nor can they be shown to possess any marked automatic activity, but it is supposed that they preside over the nutrition of the nerve itself, for if the roots be cut off, that part of the posterior root attached to the cord de- generates, while the piece attached to the ganglion remains intact. This is not the case where the anterior or motor root is cut, since under these circumstances that portion of the nerve next the cord remains intact, while the divided portion undergoes degeneration. From this it would appear that the nutrition of the sensory nerves is governed by the ganglia, while that of the motor nerves is governed by centres in the cord itself. 118 ESSENTIALS OF HUMAN PHYSIOLOGY. What is the Ritti-Valli law ? If a nerve be separated from its centre, or if the centre dies, the excitability of the nerve is increased; the increase begins at the central end and travels toward the periphery—the excitability then falls rapidly until it disappears entirely. Do these changes take place more rapidly in the central or peripheral end ? They take place more rapidly in the central end. In other words, the peripheral end remains excitable for a longer time than the central end. THE PHYSIOLOGY OF THE CEREBRO- SPINAL NERVOUS SYSTEM. The physiology of the cerebro-spinal nervous system includes that of the spinal cord and the medulla oblongata, the brain, and the nerves given off from each one of them, and the functions of the ganglia on those nerves. What is the function of the membranes of the brain and spinal cord? The dura mater is a tough membrane, and composed of bundles of connective tissue, whose function it is to enclose, and, to a cer- tain extent, protect the nervous tissue beneath it. The arachnoid is a much more delicate membrane, similar in structure to the dura mater, the function of which is to secrete the cerebro-spinal fluid. The pia mater consists of immense numbers of bloodvessels, which dip down and nourish the surface of the brain. What do you mean by the neuroglia ? A special form of connective tissue which supports the nerve- fibres and the cells of the brain and spinal cord. Of what does the spinal cord consist ? It is a cylindriform column of nerve-substance connected with the brain through the medium of the medulla oblongata and pons Varolii, and terminating in the midst of the roots of the many nerves which form the cauda equina. It is composed of white and CEREBRO-SPINAL NERVOUS SYSTEM. 119 gray nervous matter, of which the white is situated externally and constitutes the chief portion, while the gray occupies its central portion, and is so arranged that on the surface of a transverse section it appears like two somewhat crescentic masses, connected together by a narrow portion or isthmus. Is the spinal cord )f the same size throughout its whole length ? No; it varies greitly. It is very large in the middle and lower part of the cervical region and at the 1c vest part of the dorsal region, since at these two points a large number of nerve fibres are given off. Of what does the white substance the spinal cord consist? Of nerve fibres with a medullary sheath. What is the function of these nerve fibres ? The transference of impulses from cell to cell. Of what does the gray matter consist ? Of a dense network of naked nerve fibrils with numerous gan- glionic cells scattered between them. The nerve fibres in this substance also transmit impulses from cell to cell. Does the white or the gray substance contain the ganglionic cells ? The gray substance. What are these cells called ? Multipolar, bipolar, or unipolar cells, for the reason that they possess processes, one or more in number, which do not divide in. the same way as do the interlaced nerve fibres. What groups of nerve cells have we in the gray matter ? 1. In the anterior cornua are cells which are the points of origin for the motor spinal nerves. (See Fig. 16.) 2. The tractus intermedio-lateralis, a group of nerve cells mid- way between the anterior and posterior cornua, near the external surface of the gray matter. (See Fig. 16.) 3. The posterior vesicular columns of Clarke and Stilling are found in the posterior cornua near the inner surface. (See Fig. 16.) ESSENTIALS OF HUMAN PHYSIOLOGY. 4. The substantia gelatinosa cinerea of Rolando is scattered throughout the gray matter, but is chiefly found in the posterior cornua. (See Fig. 16.) Fig. 16. Direct pyrami- dal tracts, or column of Tiirck. Cells of origin / of anterior nerve roots. Anterior column, and anterior radicular zone. Antero-lateral column. - Gray substance. _ Crossed pyramidal tract. Cerebellar tract. Column of Goll. Intermedio- lateral tract. Vesicular column of Clarke. Gelatinous substance of Rolando. Posterior column, or Column of Burdach. posterior radicular zone. Transverse section of the spinal cord at level of the upper dorsal vertebra'. (See scheme below.) Into how many columns is the spinal cord divided ? Three on each side. The following scheme will illustrate this more clearly than words, particularly if the figure is also examined. The direct or uncrossed pyramidal tracts, or column of Tiirck, or antero-median column. The anterior ground bundles, or anterior radi- cular zones. 1. Anterior columns Goll’s column, or the postero-median column. Burdach’s columns, or the posterior radicular zones, the posterior lateral columns or the funiculus cuneatus. 2, Posterior columns The anterior and lateral mixed paths. The crossed pyramidal paths. The direct cerebellar paths. 3. Lateral columns CEREBRO-SPINAL NERVOUS SYSTEM 121 Fig. 17o Fig. 18. Transverse section of spinal cord of monkey ; lumbar region. (After Ferrier.) Same, but in dorsal region. (After Ferrier.) Fig. 19. Same, but in cervical region. (After Ferrier.) A, Anterior cornu. P, Posterior cornu, a, Anterior column. I, Lateral column. p, Posterior column, ac, Anterior commissure, ae, External cell groups ; and at, in- ternal cell groups, of anterior cornu, af, Anterior median fissure, ar, Anterior roots. cc, Central canal, fr, Formatio reticularis il, Cells of the tractus intermedio-lateralis. vc, Clarke’s vesicular column, pc, Posterior commissure, pf, Posterior median fissure. pm, Posterior median column (column of Goll), pr, Posterior roots, sg. Substantic gelatin osa. 122 ESSENTIALS OF HUMAN PHYSIOLOGY. Give the boundaries of each column. The anterior column is that tract which lies between the anterior median fissure and the point of emergence of the anterior nerve roots; the lateral column lies between the point of emergence of the anterior and posterior roots, and the posterior column between the posterior roots and the posterior fissure. What are Goll’s columns ? The posterior median columns, the functions of which are not as yet definitely known. What are Turck’s columns ? The anterior median columns, or the direct pyramidal tracts. They conduct impulses from the brain in the same manner as do the lateral columns. The Functions of the Spinal Cord. In what manner is conduction carried on by the spinal cord? It carries the sensory impulses transmitted to it by the sensory nerves up to the perceptive centres in the brain, and the motor impulses from the brain down to the nerves which are distributed to the muscles. Roughly speaking, what portion of the cord may be con- sidered motor, and what portion sensory ? The anterior portion is motor; the posterior, sensory. What difference is there in the function of the white and gray matter ? According to Schiff, and most physiologists, the gray matter transmits in all directions both sensory and motor impulses which are purely reflex in character, or, in other words, only intended to remain in the cord, while sensory impulses which are to go to the brain, or motor impulses which pass from the brain, must travel by the white matter. It will be remembered that both the anterior motor and the posterior sensory nerve roots do not arise from the white matter, but from the horns of the gray. CE R E BRO -SP IN AL NERVOUS SYSTEM. 123 The function of the gray matter in the posterior horns is, there- fore, limited to the receipt and transmission of sensory impulses from the periphery to the white matter, which will conduct them to the brain, or across the cord to a motor cell to complete a reflex action.1 The function of the gray matter of the anterior horns is limited to the transmission of motor impulses from the white matter to the motor nerve trunks, or to the originating of a reflex movement. What function is supposed to be possessed by the gray matter around the central canal of the spinal cord ? To transmit sensory impulses up to the brain without their having to pass through the white columns. In what way can you prove, physiologically, that the anterior columns of the cord are motor and the posterior sensory? If the posterior columns be destroyed, the foot may be burnt off but no signs of pain are elicited. If, upon the other hand, the anterior columns be destroyed, burning of the foot produces violent pain-cries, but the animal is unable to send the impulse from the brain to the leg and draw it away from the injury. Another method is to destroy a motor centre in the brain, and some time later, the animal being killed, tracts can be traced down- ward which have undergone sclerosis or atrophy. Similarly tracts may be traced from the periphery to the centres by destruction or inflammation of a sensory nerve. This has not yet been found in /he lateral sensory fibres. What is the function of the direct or uncrossed pyramidal tracts of the anterior columns and the crossed pyramidal tracts of the lateral columns ? They carry all the impulses from the central convolutions of the cerebrum, by which voluntary movements are executed. Are the lateral columns solely efferent in function ? No ; for after destruction of the posterior columns of the cord, burning of the foot causes signs of pain. 1 For definition of a reflex movement, see page 125. 124 ESSENTIALS OF HUMAN PHYSIOLOGY. What is the function of the direct cerebellar paths of the lateral columns ? They connect with the cerebellum directly by ascending fibres, which proceed through the restiform bodies from Clarke’s columns of nerve cells in the gray matter. They connect the posterior nerve roots of the trunk (not of the extremities) with the cerebellum. What is the function of the anterior ground bundles of the anterior columns, and the anterior and lateral mixed paths of the lateral columns ? They connect the gray matter of the spinal cord with that of the medulla, and carry reflex impulses. They also contain those fibres which are the direct continuation of the anterior spinal nerve roots which have entered the gray matter. The anterior and lateral mixed paths of the lateral columns also contain some sensory paths. This explains how the afferent impulses just spoken of travel to the medulla. What is the function of Goll’s column ? It unites the posterior roots with the gray nuclei of the posterior pyramids, otherwise known as the funiculi gracili, and carries impulses centripetally. By what is the nutrition of these various conducting paths governed ? By nutritive centres, in the case of the centripetal tracts, situated in the cerebrum. In the centrifugal, or motor, tracts these centres are situated in the anterior cornua of the cord. What classification can we make in the function of the nervous centres in the cord? Their functions can be divided into conduction, transference, reflec- tion, and automatism, or the power of originating impulses in them- selves. Give an example of conduction through a nerve centre. If an impulse travels from a peripheral sensory nerve to a single centre in the spinal cord reflexly it may produce contraction in the muscles which are tributary to the motor centre next to it. CE REBRO-SPIN AL NERVOUS SYSTEM. 125 This stimulation, if strong enough, may cause an impulse to travel to all the other centres in the cord, so that general muscular move- ments may take place. Give an example of the transference of nerve force. The pain in the knee or ankle occurring during hip disease is a good example of this condition, and is supposed to be due to the fact that the sensory nerves running from the hip carry impulses up to the sensory cells in the spinal cord, which again transfer the sensation they receive to sensory centres in direct communication with the area of the knee or ankle. Under these circumstances the brain receives the impulse from the two sets of fibres and mis- interprets the real cause of the sensory impulse. The impulse, under these circumstances, may be divided into two portions, the first of which is the primary, and goes to the brain directly from the cells in communication with the hip, while the other is the secondary, and is due to the transference to other centres of the impulse before it reaches the brain. If the primary and secondary impulses reach the brain together the pain is referred to both the hip and knee. What do you mean by the reflexion of nerve force, or reflex action ? Reflex action is due to the fact that an impulse travelling from the periphery to the body along the sensory nerve reaches the same point at which a sensory or receptive cell and a motor or ex- pulsive cell exist side by side. Under these circumstances the sensory cell transfers an impulse to the motor cell, by conduction, which in turn starts an impulse down along its tributary motor nerve, with the result of contraction in the muscle which it supplies. Give an example of this. If the foot of a frog be pricked, the leg which is pricked, and to a certain extent the other leg, are immediately jerked away. That this jerking away of the leg is not due to the fact that the brain desires to remove the leg from the irritation, is proved by the fact that if the spinal cord be cut, thereby preventing any impulses from reaching the brain, reflex action is as marked as if the cord was intact. 126 ESSENTIALS OF HUMAN PHYSIOLOGY. What is Setschenow’s reflex inhibitory centre ? A centre situated in the upper portion of the spinal cord whose function it is to prevent excessive reflex action. If it were not for this centre the pricking of a pin would cause but a slight reflex contraction of the leg, while a violent blow would send such an impulse to the reflex centres that a severe convulsion or tonic spasm might result. Under these circumstances, however, the reflex inhibitory centre controls the motor centres of the spinal cord and prevents their sending out impulses which would be too violent. What is automatism ? The originating, entirely independent of any external cause, of an impulse in a nerve cell. What special centres have we in the spinal cord ? Centres which govern the bladder and genital organs. What effect has irritation applied directly to the anterior and lateral white columns ? It produces muscular movements but no pain, and they are consequently excitable but insensible.1 Are the posterior columns, when irritated, sensitive or insensitive ? They are very sensitive, particularly near the origin of the posterior roots. Is this sensibility due to the presence of sensory nerve filaments belonging to these columns, or simply to the presence of the fibres of the posterior roots ? It is simply due to the fibres of the roots. What effect has section of the antero-lateral columns ? It abolishes all power of voluntary movement in the lowej. extremities. 1 This has been denied by Van Deen and Schiff, but has been proved correct by Fici., Mendelsohn, Ludwig and Woroschiloff, and Horsley. CERE BRO-SPINAL NERVOUS SYSTEM. 127 What effect has section of the posterior column ? The power of muscular coordination is lost. It is these columns which are diseased in locomotor ataxia. Is the transference of impulses stopped by this ? No; because of the sensory fibres in the lateral columns. Does the gray matter respond in any way under the influence of direct stimulation ? No, it does not. What is the result of a lesion of the spinal cord in the lower part of the sacral region ? There is paralysis of the sphincters of the rectum and bladder and of the accelerator urinae and the compressor urethrae muscles. What is the result of a lesion high up in the sacral region ? Paralysis of the muscles of the bladder, rectum, and anus; loss of sensation and motion in the muscles of the leg, except those supplied by the anterior crural and obturator nerves. What is the effect of a lesion of the upper part of the lumbar region ? Loss of motion and sensation in both legs; loss of power over rectum and bladder; paralysis of the muscles of the abdominal walls. As a result of this, there is some interference with respira- tion. What effect has a lesion of the cervical part of the cord ? It produces palsy, as do the other lesions named, with, in addi- tion, paralysis of all the intercostal muscles, and, as a result, great interference with respiration. There is paralysis of the muscles of the upper extremities except those of the shoulders. If a lesion occurs at the upper cervical region, death is instantaneous from respiratory failure. 128 ESSENTIALS OF HUMAN PHYSIOLOGY. The Medulla Oblongata. The points to be remembered concerning this portion of the nervous system are as follows : Its columns are continuous with those of the spinal cord, and each half of it may be considered to be divided into three columns or tracts of fibres, in the same manner as they occur in the spinal cord. What difference exists between the columns here and in the cord? They are more prominent, and separated from each other by deeper grooves. What are these columns of the medulla called ? Pyramids; the anterior columns are called the anterior pyramids, those of the posterior columns restijorm bodies and posterior pyramids. Fig. 20. Anterior median fissure. Pyramid. Hypoglossal nerve. Olivary body. Vagus nerve. Membrana reti- culata Origin of the tri- facial. Respiratory centre Continuation of cerebellar tracts. Posterior column Diagram showing cross section at level of fourth ventricle. MEDULLA OBLONGATA. 129 What are the direct pyramidal tracts ? The anterior pyramids which pass directly upward to the cere- brum without crossing to the other side. What are the crossed pyramidal tracts? Those fibres of the lateral columns which cross to the opposite anterior pyramid. What is the olivary body ? On the outer side of each anterior pyramid is a small oval mass of gray matter, the olivary body. What is the posterior pyramid ? A small tract marked off from the posterior part of the restiform bodies on each side by a slight groove. What forms the fourth ventricle ? The restiform bodies diverge, and by so doing lay open a space— the fourth ventricle. What is the distribution of the fibres of the medulla oblongata ? The anterior pyramids receive fibres from the middle fibres of the lateral columns of the cord, not only from the same side but from opposite sides. In other words, some of the lateral fibres of the left side enter the anterior pyramid of the right side and vice versa. These are the crossed pyramidal tracts already mentioned. What is the crossing from one side to the other called ? Decussation. After this occurs, what happens next ? The anterior pyramids with their new fibres pass on upward, the greater part going through the pons to the cerebrum, while a smaller part joins some fibres from the olivary body forming the olivary fasciculus or fillet. Still another small mass of fibres pro- ceeds to the cerebellum. What course do the fibres of the lateral columns pursue ? The outer fibres go with the restiform tract to the cerebellum, the middle decussate to the anterior pyramids as already stated, 130 ESSENTIALS OF HUMAN PHYSIOLOGY. and the inner pass on to the cerebrum along the floor of the fourth ventricle. What is the direct cerebellar tract? The outer fibres of the lateral columns first named. Do the impulses of the will which arise in the brain pass down each side of the spinal cord directly and produce contractions in muscles of the same side ? No, they do not. The fibres carrying these impulses cross each other in such a way that impulses arising in the left side of the brain are made manifest on the right side of the body, while those arising in the right side of the brain are made manifest in the left side of the body. Why is this so ? The decussation of part of the fibres of the anterior pyramids of the medulla transfer impulses across the cord. Does this same transference of impulses take place in the sensory tract, or, in other words, is a sensation occurring in the left foot recognized in the right hemisphere of the brain ? Yes. Does the transference take place in the medulla ? No, it does not. The posterior fibres do not decussate in the medulla, but Brown-Sequard has shown that the crossing takes place in the spinal cord. What effect has section of a lateral half of the spinal cord ? It produces paralysis of motion on the injured side, but does not affect sensation in the least on that side. On the uninjured side motion is preserved but sensation lost. THE MEDULLA OBLONGATA. 131 Why is this so ? Because, as has already been stated, the motor impulses are not transferred in the cord but in the medulla, while sensory impulses are transferred in the cord. What is the function of the medulla oblongata ? In many ways it is similar to that of the spinal cord for it carries on conduction, transference, reflexion, and automatism. It is in this portion of the nervous apparatus that the decussation of part of the fibres of the anterior cornua of the medulla takes place, ex- plaining the phenomenon which has just been mentioned in regard to paralysis occurring on the opposite side from the lesion. What special centres exist in the medulla oblongata ? First, the respiratory centre, whose function it is to send out those impulses which result in respiratory movements, and the interference with which causes great disorder of respiration or death; second, it contains the hypoglossal nuclei for deglutition which send out the impulses which produce the movements neces- sary to the acts of swallowing; third, a centre for the movements of mastication; fourth, the chief vaso-motor centre which governs the bloodvessels all over the body (see Circulation); fifth, the cardio-inhibitory centre for the regulation of the movements of the heart through the pneumogastrics; sixth, the superior cilio-spinal centres which govern the movements of the iris1; seventh, the inner and outer nuclei of the special sense of hearing; and eighth, the glosso-pharyngeal nuclei for the sense of taste; ninth, the centres for vomiting. The medulla oblongata also gives rise from its posterior surface and its continuation to the cranial nerves from the 12th to the Sth inclusive. (See Figs. 21 and 22.) How do you know that the medulla contains all those centres which are necessary for the continuance of life ? Because the brain and cerebellum can be destroyed and yet the respiration and heart go on unimpaired. 1 Remember that the inferior cilio-spinal centre acts thus also. 132 ESSENTIALS OF HUMAN PHYSIOLOGY. Fig. 21. Diagram of posterior aspect of medulla oblongata showing positions of the nuclei of the cranial nerves. (After Erb and Ferrier.) v, Motor nucleus; v', middle; and v", inferior sensory nucleus of the fifth nerve; vi, abducens nucleus; vn, facial nucleus; vm, inner, and vm', outer auditory nucleus ; vm" and vm'", divisions of the anterior auditory nucleus ; ix, glosso-pharyngeal nucleus; x, vagus nucleus; xi, accessorius nucleus; xn, hypoglossal nucleus; 1, middle cerebellar peduncle ; 2, superior cerebellar peduncle; 3, inferior cerebellar peduncle; 4, eminentia teres; 5, stri® acoustic®; 6, ala cinerea. Fig. 22. Diagrammatic representation of the nuclei of the cranial nerves as seen on section. The left half is supposed to he removed, and the nuclei near the median line are shaded darker than the others. (After Erb and Ferrier). Py. Pyramidal tracts. PyKr. Decussation of the pyramids. 0. Olivary body. Os. Upper olivary body. Roman numbers have same meaning as in other cut. Kz. Clavate nucleus. Rv. Roots of fifth nerve. Rvi. Roots of sixth, or abducent nerve. Rvii. Roots of facial nerve. THE MEDULLA OBLONGATA. 133 What is the function of the pons Varolii? It contains a large number of nerve fibres both transverse and longitudinal, and is a conductor of impressions from one part of the spinal axis to another. Concerning its functions as a nerve centre little or nothing is certainly known. What are the functions of the crura cerebri ? They are formed of nerve fibres, of which the inferior or super- ficial are continuous with those of the anterior pyramidal tracts of the medulla, and the superior or deeper fibres with the lateral and posterior pyramidal tracts, and with the olivary fasciculus. Each crus cerebri contains among its fibres a mass of gray substance known as the locus niger. They act principally as conducting organs. As nerve centres they are probably connected with the functions of the oculo-motor nerves through which are directed the numerous movements of the eyeball. They are also connected with the coordination of other movements than those of the eye. What is the result of injury to the crus cerebri ? Either rotatory or disorderly movements, with loss of coordina- tion, result. What is the function of the corpora quadrigemina or optic lobes ? Removal of those bodies produces total loss of vision ; destruc- tion of one of them produces blindness in the eye of the opposite side. It also produces rotatory movements of the body resembling those occurring after division of the crus cerebri, save that the movements are slower. What is the effect of injury to these bodies ? They cannot be said to be the centres of vision, but seem to be the centres of correlation between retinal impressions and oculo- motor reactions. 134 ESSENTIALS OF HUMAN PHYSIOLOGY. What is the function of the corpora striata ? They are centres of innervation for the same movements as exist in the cerebral cortex, but of a lower grade of specialization. Injury to the corpora striata on one side prevents the communi- cation between the will and the muscles of the opposite half of the body, so that palsy results, or, in other words, hemiplegia. The corpus striatum may, therefore, be considered as the motor con- nection between the cerebrum and the crus cerebri. Fig. 23. Diagram of brain and medulla oblongata, a, spinal cord; b, b, cerebellum divided, and above it the valve of Vieussens partially divided ; c, corpora quadrigemina; d, d, optic thalami; e, pineal body ; /, f, corpora striata; g, g, cerebral hemispheres in section ; h, corpus callosum ; i, fornix; Z, Z, lateral ventricles; 3, third ventricle; 4, fourth ventricle ; 5, fifth ventricle, bounded on each side by septum lucidum. (Cleland ) What is the function of the optic thalami ? If the optic thalamus is destroyed on one side sensation of the opposite side of the body is impaired or lost. It is, therefore, regarded as the sensory band between the cerebrum and the crus cerebri. THE MEDULLA OBLONGATA. 135 What are the functions of the cerebellum ? It is absolutely insensible to irritation and may be cut away without any signs of pain; its removal from the body or destruc- tion by disease is generally unaccompanied by loss or disorder of sensibility. Animals from which it is removed can see, hear, and feel pain to all appearance as perfectly as before. It governs the coordination of movements, and while irritation of the cerebellum produces no movements at all, remarkable results are produced by removing part of its substance. As portion after portion of it is cut away the animal gradually loses the power of springing, walk- ing, standing, or preserving its equilibrium. If laid upon its back it cannot recover its normal posture but struggles to get up, and if a blow is threatened tries to avoid it, but fails to do so. According to Gowers, the middle lobe of the cerebellum governs equilibrium by means of afferent fibres from the semicircular canals and the ocular muscles and also the muscles of the legs. What other function has the cerebellum ? The middle lobe is also very closely associated with the vagus, and this is the reason that we are so apt to have vomiting with vertigo or in cerebellar disease. What results do we gain, therefore, from these experi- ments? We know that the cerebellum has no connection with volition, sensation, and memory, but merely has the faculty of combining the action of the muscles and producing thereby the movements intended by the higher nervous centres. Remember, that the influence of each half of the cerebellum is directed to the govern- ment of the opposite side of the body, and that both halves must act in unison, or, otherwise, strange disorders of motility result. What is the mean weight of the brain ? The mean weight of the brain in man is 1358 grammes, in woman it is 1220 grammes. 136 ESSENTIALS OF HUMAN PHYSIOLOGY. What position does the gray matter occupy in regard to the white ? The gray matter forms the cortex and is outside the white. Which is the most vascular ? The gray matter is much more vascular than the white. Fig. 24. 1,1, Medullary arteries ; and 1', 1", in groups between the convolutions ; 2, 2, arteries of the cortex cerebri; <i, large-meshed plexus in first layer ; b, closed plexus in middle layer; c. more open plexus in the gray matter next the white substance, with its vessels (d). (Landois.) What two varieties of bloodvessels do we have in the brain ? The long medullary arteries which, as their name implies, pass from the pia mater to the white matter through the gray, and the cortical arteries which in great part enter the gray matter of the cortex only, although some pass down to the white matter. THE MEDULLA OBLONGATA 137 What difference is there between these two sets of arte- ries ? The medullary arteries are terminal and do not anastomose, while the corticals do anastomose and are, therefore, not terminal arteries. What is the physiological significance of this ? A thrombus or embolus in one of the medullary arteries pro- duces a total starvation of the area supplied by it, but if such an accident occurs to one of the corticals then the collateral circula- tion prevents a total cutting off of blood ; therefore, we find that the most important portion of the cerebrum is supplied in such a way that it is guarded against accident, while the white matter which is not nearly so important is unprotected. (See Fig. 24.) What arrangement of bloodvessels have we for the nutri- tion of the rest of the brain and the portions of the nervous apparatus ? From trunks constituting the circle of Willis branches are given off which pass upward and enter the brain to supply it with blood. Are these arteries terminal, or do they anastomose with each other? They are terminals, and do not anastomose. What is the function of the cerebrum ? The cerebral hemispheres are the organs by which perception is carried on and from which motor impulses are given out. They contain the organ of the will; they possess memory, or the means of retaining impressions of sensible influences; and they are the medium of all the higher emotions and feelings. They carry on intellection as is evidenced by imagination, understanding, reflec- tion, and judgment. How do we know that consciousness depends upon the action of the cerebral hemispheres ? If they are injured in any way, consciousness is lost—as, for example, during an apoplectic fit. 138 ESSENTIALS OF HUMAN PHYSIOLOGY How do we know that it is in the cerebral hemispheres that the intellect is situated ? Because the higher the intellect is the greater development is possessed by the brain, and because destruction of the cerebrum stops intellection. Congenital and other morbid conditions of the hemispheres always produce disorders of the intellect. What effect has the extirpation of the cerebrum ? After the removal of both cerebral hemispheres in animals, every voluntary impulse, every conscious impression, and every sensory perception ceases, but the maintenance of the equilibrium and all the mechanical movements of the body are preserved. What example of this can you give ? A frog with its cerebrum removed retains its power of main- taining its equilibrium. It can sit, spring, or execute complicated movements which are coordinated, and when it is placed upon its back immediately turns right side up again. What is the purpose of the convolutions ? In order to give a greater surface for the spreading of the cells in the cortex without making the brain so large that the skull would be out of proportion to the body. What do you mean by cerebral localization ? The determination of the areas in the cerebral hemispheres governing various portions or functions in the body. Where is the speech centre located in the cerebrum ? In the third frontal convolution and the Island of Reil. On which side of the brain is the speech centre best developed ? The left side. THE MEDULLA OBLONGATA. 139 What are these areas? The surface of the cerebrum may be divided into three sections —anterior, middle, and posterior. The anterior lobes contain the cells for intellection, the middle areas the cells for motion, and the posterior lobes those for sensation or perception. As an example of some of the motor centres, give the area for the arm and leg. Stimulation of the upper extremity of the ascending parietal and ascending frontal convolution causes movement of leg, while stimulation of these two areas lower down causes movements of the arm. What is the relative position of the chief centres in the brain ? It is a fact that the centres which govern the more massive parts and which govern the lower regions of the body are high up in the brain, while the centres for the control of the face and arm, for example, are lower down on the surface of the cortex. What portion of the brain perceives pain ? Horsley has shown that destruction of the gyrus fornicatus prevents the perception of pain. In what two ways are these impulses carried to the lower portions of the nervous system ? From all this area radiating fibres converge to the base of the brain, where some of them pass through the corpora striata and its three nuclei (the caudate, lenticular, and taeniform), while others pass through the internal capsule. What course do these fibres now take ? After leaving the internal capsule these fibres once more meet some of those fibres which passed through the nuclei of the cor- pora striata and form the crustae of the crura cerebri, which con- tinuing downward through the pons Varolii emerge from its posterior and lower border in the form of the anterior pyramids of the medulla oblongata. 140 ESSENTIALS OF HUMAN PHYSIOLOGY. What course do centripetal impulses take to get to this portion of the brain ? When the sensory fibres of the spinal cord reach the medulla oblongata they pass up on either side of the motor nuclei to form Fig. 25. Diagram of some of the paths taken by nerve impulses in the brain and spinal cord. 3. Gray substance of cerebral cortex, <?■ Gray substance of cerebellum, er. Cranial nerves, some afferent and some efferent. M. Motor (efferent) spinal nerves. S. Sensory (afferent) spinal nerves. (Yeo.) the tegmenta, and to become connected with the optic thalami, corpora geniculata, and corpora quadrigemina. From these ganglia radiating fibres pass to the receptive areas of the brain. THE CRANIAL NERVES. 141 THE CRANIAL NERVES. It will be remembered that, according to most anatomists, the cranial nerves are divided into twelve pairs. 1. What is the function of the olfactory nerve ? It is the nerve of special sense by which odors are distinguished; in other words, it is the nerve of smell. It is distributed to the mucous membrane of the nose, and arises superficially from the lower part of the frontal lobe in advance of the anterior perforated space, passing through the cribriform plate of the ethmoid bone. 2. What is the function of the optic nerve ? It is the nerve of sight, and is distributed to the retina of the eye. It arises superficially from the geniculate and quadrigeminal bodies and thalamus, and passes out through the optic foramen of the orbit. It conveys no other impulses than those of sight. What is the effect of division of one of the optic nerves ? It produces complete blindness in the eye of the corresponding side. What is the effect of division of thefrptic tract? It produces loss of sight in the outer half of the eye of the same side, and of the inner half of the eye of tlje opposite side. What is the effect of injury to the interior part of the optic chiasm ? It causes blindness in the inner half of both eyes. 3. What is the function of the oculo-motor nerve ? It is the motor nerve of the levator palpebrarum, the superior, internal, and inferior rectus, and the inferior oblique muscle of the eye. Its superficial origin is the inner side of the cerebral crus, and it finds its exit from the sphenoidal foramen. It also supplies filaments to the ciliary ganglia from which the ciliary nerves arise, which enter the eyeball and are distributed to the circular fibres of the iris and the ciliary muscle. It governs the accommo- dation of the eye. 142 ESSENTIALS OF HUMAN PHYSIOLOGY. What effect has stimulation of the oculo-motor on the pupil ? It causes contraction of the pupil, internal strabismus, and mus- cular movements of the eye, but no pain. Section of the nerve is followed by ptosis, or drooping of the upper eyelid, internal stra- bismus, due to the supposed action of the external rectus muscle, and paralysis of the accommodation of the eye. 4. What is the function of the pathetic nerve ? It governs the movements of the eyeball so far as those are con- cerned which are produced by the action of the superior oblique muscle; it arises from the valve of Vieussens and passes through the sphenoidal foramen. 5 What is the function of the trifacial nerve ? It is a nerve of sensation, motion, and taste. It arises from the side of the pons by a smaller motor and a larger sensory root, and is divided into three divisions, the first of which supplies the conjunctiva, the lachrymal gland, the eyeball, the upper eyelid, the integument of the forehead, and the mucous membrane and integument of the nose. The second division supplies the lower lid and conjunctiva, the temple, upper lip, nose, cheeks, and teeth of the upper jaw. These two divisions are purely sensory. The third division supplies the muscles and skin of the lower part of the face, the muscles of mastication, the teeth in the lower jaw, the tongue, the parotid gland, and the auricle of the ear. This di- vision contains motor, sensory, and other filaments which carry the sense of taste. What is the effect of irritation of the larger root of the trifacial nerve ? It produces marked evidence of pain, which is always felt in the periphery of the nerve, since it will be remembered that pain arising at the origin of a sensory nerve is always referred to its peripheral filaments. Irritation of the small root produces move- ments of the muscles of mastication, whilst section of this root causes paralysis of these muscles. Section of the large root is 1 For medullary origin of all the rest of the cranial nerves, see page 121. THE CRANIAL NERVES 143 followed by a complete abolition of sensibility in the head and face, but no disturbance of motion. 6. What is the function of the abducent or sixth pair of nerves ? Motion, which results in turning the eyeball outward. They arise from the anterior pyramids, and supply the external rectus muscle of the eye. Stimulation of this nerve causes outward rotation of the eyeball, while paralysis of it causes internal stra- bismus. 7. What is the function of the facial nerve ? It supplies the motor filaments of the muscles of the ear, scalp, and face—platysma, digastric, and stylohyoid muscles—and arises between the olivary and restiform bodies. It finds its exit through the internal auditory meatus, the facial canal, and the stylo- mastoid foramen. What is the peculiarity of the facial nerve? It is a motor nerve in its origin, but in its course receives sensory filaments from the fifth pair and the pneumogastric. Irritation of the facial produces muscular contractions, while division produces paralysis of the muscles of the face. Remember, that it is this nerve which gives off the chorda tympani, that branch which supplies the bloodvessels and secretion of the sublingual and sub- maxillary glands and the sense of taste in the anterior two-thirds of the tongue. 8. What is the function of the auditory nerve ? It governs the sense of hearing, conducting the impulses from the exterior to the brain. It rises in the floor of the fourth ven- tricle, and is distributed to the labyrinth of the ear. Destruction of this nerve produces deafness. 9. What is the function of the glosso-pharyngeal nerve ? It governs the sensibility of the pharynx, and therefore influences taste. It has also motor filaments which pass to the root of the tongue, the tonsils, the soft palate, the pharynx, and the tympanum. 144 ESSENTIALS OF HUMAN PHYSIOLOGY. 10. What is the function of the pneumogastric or vagus nerve? It is chiefly made up of sensory filaments which anastomose with motor filaments from other sources. It influences deglutition, the action of the heart, the circulatory and respiratory systems, the voice, and the stomach. It arises from the fore part of the restiform body and the vagal nucleus of the floor of the fourth ventricle. The functions of its branches have been considered when studying the circulation, respiration, etc. 11. What is the function of the spinal accessory nerve ? It is made up of motor filaments, some of which pass to the vagus nerve, while others supply the sterno-mastoid and trapezius muscles. It arises from the lateral columns of the spinal cord and the gray substance within. It will be remembered that it consists of two parts, a smaller accessory root whose deep origin is in a nucleus of gray matter at the back of the medulla below the origin of the vagus, and a large spinal root from the lateral columns of the cord. What is the effect of destruction of its medullary root? It produces paralysis of the laryngeal muscles, resulting in aphonia, and impairs the action of the muscles of deglutition. Irritation of the spinal root produces contractions of the trapezius and sterno-mastoid muscles, but section of this branch does not produce absolute palsy in these muscles, since they are supplied by motor filaments from elsewhere. 12. What is the function of the hypoglossal or sublingual nerve ? Its function is motor and it governs all the movements of the tongue, influences mastication, deglutition, and articulate language. It rises from the anterior pyramid, the olivary body, and the hypoglossal neucleus. Irritation of it produces convulsive move- ments of the tongue, while division of it abolishes all these move- ments and interferes considerably with deglutition; articulation is considerably impaired, and mastication is performed with diffi- culty from inability to retain the food between the teeth. THE SPECIAL SENSES. 145 What do you mean by the term ‘nerves of special sense”? Those nerves which carry, as do sensory nerves, impulses from the periphery to those centres in the brain which may perceive and interpret them, and which differ from the ordinary sensory nerves in that, as a general rule, the impulses are not the result of ordinary stimulation by contact, but of one special form of irrita- tion. As an example of this the optic nerve appreciates light, yet light can never be said to produce activity of the nervous proto- plasm by contact; nor do the vibrations of air produced by sound cause any impulses to travel along any sensory nerves save the auditory; neither can we say that the olfactory nerves are stimu- lated mechanically by the presence of substances so small that they cannot be distinguished by spectrum analysis, but which, nevertheless, are perceived by the nostrils; this is the reason why each one of the nerves carrying the impressions of sight, smell, taste, or sound, are called special, since each one of them can transmit but one variety of impulse. Bo the nerves which carry these impulses of special sense differ from other nerves in their structure and ordinary capabilities ? No; they differ in no way at all from ordinary afferent nerves, with one or two exceptions. Is the sensation recognized at the point at which the cause exists, or by the special centres in the brain ? It is recognized in the centre, but, as has been stated before, impulses in sensory nerves are always referred to the periphery, and, therefore, we are accustomed to say that we feel the burn or other injury at the spot where it occurs. By what means is this peculiar condition in regard to sensation governed ? It is solely governed by the mind itself, which has been taught to do this as the result of education, experience, and habit, acquired by a long series of unconscious experiments in early youth. THE SPECIAL SENSES. 146 ESSENTIALS OF HUMAN PHYSIOLOGY. What is necessarily present for a complete special sense apparatus ? First, a special nerve ending, only capable of being excited by special forms of stimuli; second, an afferent nerve to conduct the impulse from the special end organ to the nerve centre; third, nerve cells forming a centre, which is capable of translating the impulse received into a sensation and of referring that sensation to some local point; fourth, associated nerve centres capable of per- ceiving sensations, forming ideas, and drawing conclusions there- from, with the object of determining the position, character, and intensity of the external influence. The Sensibility of the Skin. Those impulses which are received through the skin are obtained through the sense of touch. Into how many divisions is this sense of touch subdivided? First, tactile sensibility, by means of which we appreciate the slightest touch and recognize the exact point at which the skin receives the impulse. Second, the sense of pressure, by which we are enabled to judge of the compression which is being exerted on a certain area; this sense, however, is by no means so well developed as the tactile sense. Third, the sense of temperature, by which we are enabled to determine whether an object is hot or cold. This sense, also, is not perfectly developed, since for a moment we are unable to determine whether an object is hot or cold unless the eye or other special sense aids us. What is the object of tactile sensibility? In order that we may judge of the position, character, and shape of bodies. Is tactile sensibility exceedingly important to the animal organism ? Very important, since without it nothing could be held firmly in the hand, and all the movements of the body would be seriously interfered with. THE SENSE OF TASTE. 147 In what way are the nerves arranged for tactile sensi- bility ? The sensory nerves running to the skin are endowed with endings of various forms according to their function; these forms are divided into five varieties: First, the touch corpuscles, which are egg-shaped bodies situated in the papillae of the true skin, directly under the epithelial cells of the rete mucosum ; they vary in size considerably, according to the amount of work which they are forced to perform; in these the axis-cylinder of the nerve ends. Second, the end bulbs, which are smaller than the last and differ from them in that they are only distributed to localized areas; they are made up of a little vesicle containing fluid in which the axis-cylinder terminates, the wall of the vesicle joining the sheath of the nerve. Third, touch cells, which differ from the others in that they exist in the deeper layer of the epiderm. Fourth, free nerve endings, which occur on the surface of the epi- thelium of mucous membranes. Fifth, Pacinian corpuscles, which are ovoid bodies made up of concentric layers of varying con- sistence, with a collection of fluid in the centre, in which the axis- cylinder ends. The Sense of Taste. In what way is taste produced ? By the contact of sapid substances with the endings of the gustatory nerves of the tongue in the various papillae. What are these papillae sometimes called ? “Taste buds” or “ taste goblets.” Is it possible to taste a dry substance ? No; when a dry substance is placed on the tongue the moisture dissolves or moistens at least some of it. What proof have we that this is so? If the tongue be thoroughly dried no taste is perceived. Where is the chief sense of taste situated? In the tongue. 148 ESSENTIALS OF HUMAN PHYSIOLOGY. What other surfaces aid the tongue in tasting ? The soft palate and its arches, the uvula, tonsils, and upper pharynx. The hard palate has little taste power. What is the nerve supply of the back part of the tongue? The glosso-pharyngeal. What is the nerve supply of the tip of the tongue ? The lingual branch of the trifacial nerve. What portion of the tongue perceives taste the best ? The back portion. The tip and middle of the tongue are not so well endowed with nerves.1 The sense of smell aids the sense of taste when eating. If the nostrils be closed and the eyes shut no distinction can be exercised between a piece of apple, potato, or onion on the tongue. Do certain areas of the tongue taste certain bodies ? Yes. The sulphate of quinine is scarcely noticed at the tip, at the back it is very well perceived. Sugar, on the other hand, is best tasted on the tip of the tongue. The Sense of Smell. How is the sense of smell excited ? By fine bodies floating in the atmosphere. What effect on smelling has drying of the nasal mucous membrane ? It impairs the power of perceiving odors very greatly. What is the object of sniffing'? In order to draw over the nerve endings a current of air con- taining the odor. In what way are the olfactory nerves arranged ? Most of these nerves are distributed to the mucous membrane of the middle and upper meatus of the nose. The mucous membrane 1 For the muscular movements of the tongue, see Mastication. THE SENSE OF SIGHT. 149 in this area is not covered by motile cilia such as are found in the rest of the nasal cavity; it is less vascular and of a peculiar yellow hue. The extreme delicacy of smell can best be understood when we remember that Valentin has estimated that two-millionths of a milligram of musk is sufficient to excite the olfactory nerves of man. In other animals this sense is even more acute. The Eye and its Coverings What is the function of the eyelids ? To protect the eyeballs, and to distribute moisture over them constantly, thereby preventing drying. How are they formed ? They are movable folds of skin, each of which is kept in shape by a thin plate of yellow elastic tissue. What is the function of the eyelashes ? To prevent the entrance of foreign bodies, especially when the lids are half closed. In what way do they differ from ordinary hairy growths ? They possess tactile sensibility, which causes, reflexly, the lids to close tightly when a foreign body touches them. What is the purpose of the Meibomian glands along the edges of the lids? To lubricate them, and prevent irritation from the tears. In what portion of the orbit is the lachrymal gland placed ? In the upper and outer angle. What is the use of the lachrymal gland ? To secrete liquid, which will lubricate and keep the eye moist. When an excessive secretion takes place it runs over the lower lids, in the form of tears. On what side of the orbit does the lachrymal secretion escape? On the inner side, through the puncta lachrymalia, one of which The Sense of Sight. 150 ESSENTIALS OF HUMAN PHYSIOLOGY. exists in each, lid; thence it passes into the lachrymal sac, and from there through the nasal ducts into the nose. What function has the lower eyelid which is not possessed by the upper lid? It acts as a gutter along which an excess of the tears may flow; when one cries the gutter overflows. What is the function of the orbicularis palpebrarum muscle, and what is its nerve supply ? It closes the eye, and is supplied by the facial nerve. What muscle opens the eye ? The upper lid is raised by the levator palpebrarum superior, which is supplied by the oculo-motor nerve. In what way does the ending of the optic nerve differ from any other sensory nerve ? It is enclosed in a specially arranged organ, the eyeball. What is the object of the eyeball? For the purpose of so directing the rays of light that they strike in a certain way upon the peripheral optic filaments. It also pro- tects the nerve filaments from all contact with external conditions, except light. What is the only stimulus which ordinarily excites the optic nerve ? Light. What is the purpose of the movements of the eyeball ? In order that objects may be brought within the range of vision without movements of the head. If electrical, mechanical, or other stimuli be applied to the optic nerve, what sensations will they produce ? Light is the only thing appreciated. What is the function of the sclerotic coat of the eye ? It gives shape and protection to the organ. Is the sclerotic coat continuous all over the eyeball? No, it is not; for at the anterior portion is a window-like open- ing, known as the cornea, through which the rays of light pass. THE SENSE OF SIGHT. 151 What is the function of the cornea ? It permits light to enter the eye in much the same manner as a window-pane lets light into a room, and it also effects very mark- edly refraction of the rays of light. What peculiar bodies have we in the cornea which move about ? The corneal corpuscles, which resemble amoebae in their move- ments. Does the cornea possess nerves and bloodvessels ? Only nerves, which are partly sensory in function. From what are these nerves derived ? From the long and short ciliary nerves. What change takes place in these nerves as they enter the cornea ? They enter the cornea as medullated nerve fibres, but the myelin soon disappears and leaves the naked axis cylinder. In what way, then, is it nourished ? By absorption from the bloodvessels at the corneal margin. What is the function of the choroid coat ? Owing to its black, pigmented connective tissue cells, it prevents the transmission of all light from the exterior, save by the corneal opening, and prevents reflections from side to side. It is this coat which lacks pigment in albinoes and nocturnal animals, and its absence prevents good vision in the daytime. What are the ciliary processes ? They are highly vascular folds of the choroid, occurring near the edge of the cornea. What is the function of the ciliary muscle ? It attaches the choroid to the sclerotic coat, governs the diameter and shape of the crystalline lens, and governs accommodation. 152 ESSENTIALS OF HUMAN PHYSIOLOGY. What is the function of the iris ? It is a circular membranous diaphragm provided with a central aperture, the pupil, and regulates the amount of light entering the eye. It contains two sets of muscular fibres, circular and radiating. What are the functions of these two sets of muscular fibres ? The radiating fibres dilate the pupil, the circular fibres contract it. What is the object of this pupillary movement? The regulation of the amount of light entering the eye. Have the vessels of the choroid any intimate connection with the nutrition of the eye ? Yes. Describe these bloodvessels. The arteries are the short posterior ciliary arteries, which are about twenty in number and perforate the sclerotic near the optic nerve. They terminate in the vascular network of the chorio- capillaris, which reaches as far as the ora serrata. The long posterior ciliary arteries lie on the nasal and temporal side of the eye; they run to the ciliary part of the choroid and penetrate the iris, helping to form the circulus arteriosus iridis major. The anterior ciliary arteries, which arise from the muscular branches, perforate the sclerotic coat anteriorly and give branches to the choroid and iris. What are the veins, and what is their function ? The anterior ciliary veins receive the blood from the anterior part of the eyeball and carry it outward; they do not receive any blood from the iris. In what way does the blood from the iris pass out of the eye? The venous plexus of the ciliary processes receives the blood from the iris and passes it backward to the choroidal veins. THE SENSE OF SIGHT. 153 What arrangement have we on the posterior surface of the iris to prevent the transmission of light through it? A layer of dark pigment. What is the nerve supply of the circular fibres of the iris ? The oculo-motor. What is the nerve supply of radiating or dilating fibres ? The trifacial and sympathetic. Why does the pupil contract when we are looking at near objects, but dilate for objects which are far away ? When an object is near, the rays of light are so near together that they enter through a small opening; when it is far off the pupil dilates, in order to let all the rays in that it can to make the image more distinct. What is the function of the retina ? Lying next to the choroid coat the retina is formed by the expansion of the optic nerve, and it is this membrane which receives the impression of light. What is the chemical reaction of the retina ? When fresh it is acid in light, but it is alkaline in darkness. In what way do the nerve filaments end in the retina ? In the rods and cones. Which of these is most highly developed in man ? The rods. What do you mean by the blind spot ? A small point in the retina on which, when light falls, no impulse is produced ; it is the point of entrance of the optic nerve. What do you mean by the macula lutea ? The point at which rays of light produce the greatest visual impression. It is exactly in the centre of the retina. 154 ESSENTIALS OF HUMAN PHYSIOLOGY. Are the rods or the cones in greater number here? The cones. What is the visual purple ? A certain purple substance on the retina, which is destroyed by contact with light. It has been supposed that it aids vision, but this is apparently contradicted by the fact that it is absent from the cones and the macula lutea, where vision is best. It can only be seen by opening an eye in a dark room, and flashing a light upon it. If the operation be quickly done the image falling on the retinal pigment may be made permanent by dipping it quickly in a strong solution of alum. Does every part of the retina receive all the rays of light ? No. Each portion receives different colored rays. The periph- eral portion sees the red rays, etc. What is the function of the aqueous humor of the eye ? It affords a medium in which the iris can move. It also supports the posterior surface of the cornea, and influences the refraction of light. What is the function of the vitreous humor ? It fills out the eyeball and keeps it tense, and aids very largely in the refraction of the rays of light transmitted to it through the crystalline lens. What is the function of the crystalline lens ? It acts like a strong, magnifying glass, and is biconvex. It is the most important refracting portion of the eye, and, aided by other portions of the optical apparatus, directs the rays of light in such a manner that they fall properly on the retina. It also sepa- rates the aqueous from the vitreous humor. In what way are images thrown on the retina ? They are inverted by the lens, which is biconvex. Why do we not see objects, therefore, upside down? Because the brain interprets the inverted image for one in the proper position. THE SENSE OF SIGHT. 155 What variation is there in the power of refraction of the various parts of the lens ? It increases in density, and consequently in power of refraction, from without inward. Give the essential portions of the eye for the carrying- out of its functions, namely, sight. 1. A retina or nervous mass to receive and transmit impulses. 2. Certain refracting media so arranged as to throw the rays of light in proper form. 3. A contractile diaphragm, the iris, which governs quantity of light admitted. 4. A contractile muscle, the ciliary muscle, to regulate the shape of the lens and to “ accommodate ” the eye to distances. What would be the effect if the retina was exposed to the light with no refracting media in front of it ? The perception of light from darkness, but no objects could be seen. What do you mean by the terms “refraction and accom- modation of the eye ? ” By refraction we understand that optical adjustment of the eye which depends upon its anatomical structure; the accommodation includes those changes of the optical adjustment which are effected by the ciliary muscle. When the eye is at rest is it accommodated to near or far objects ? It is accommodated for the greatest distance. What do you mean by the “ near point ? ” The “ near point ” is the nearest point at which the eye can clearly perceive an object held before it, as, for example, printed matter held close to the face. The “far point” is the same thing reversed, save that the far point in the human eye is an infinite distance. By what means do we judge of distance ? This is largely a matter of education and is unconsciously ob- 156 ESSENTIALS OF HUMAN PHYSIOLOGY. tained, in the same way as the judgment of size, a mere matter of practice. What is chromatic aberration ? It is the breaking up of ordinary white light into colored rays, owing to the different colored lights of which ordinary light is made up. It is due to a defect in the optical apparatus, but in the normal eye it is diminished by the iris, which cuts off the marginal rays. What is spherical aberration ? It depends upon the fact that luminous rays passing through a convex lens strike the various parts of the surface at different angles, and, hence, are differently refracted, the rays striking the margin of the lens being more bent than those passing through the centre. Spherical aberration does not, however, cause in- convenience, since the iris allows only the central rays to pass. What is astigmatism ? It consists in an inability to see clearly lines running at certain angles. It depends either upon some irregularity in the shape of the cornea, or in the shape of the lens. What are eutopic images'? Those which depend on the presence of some opacity in the transparent media of the eye itself. They occur in all eyes to a a certain extent, and are frequently noticed when one uses the microscope. What is the cause of color-blindness ? The inability of certain areas of the retina to perceive those rays of light which normally fall on them, owing to the imperfect development of these areas. The common forms of blindness are for the red, green, and yellow rays. What is diplopia ? Double vision, due to the fact that each eye receives the impulse at a different time from the other. THE SENSE OF SIGHT. 157 What is hemianopsia ? Blindness of one-half of the eye so that objects are split down the middle and only half of the body perceived. Since the rays of light cross in the eye, the part of the retina which is blind is always opposite the object, which cannot be seen. Thus, when the eye sees no objects to the left of it, it is the right side of the eye which is blind. What is myopia? “Short sightedness.” A condition of the eye in which objects are focussed at a point in front of the retina. What is hypermetropia ? “ Far sightedness.” A condition of the eye in which objects are focussed behind the retina. What do you mean by presbyopia ? A state common to old age, due to loss of the power of accom- modation. What is an emmetropic eye ? A normal eye. Does such an eye as an absolutely normal eye exist ? Probably not, or in very rare instances. By what form of glass would you remedy myopia ? By a concave glass. By what form of glass would you relieve hypermetropia ? By a convex glass. Why do you do this ? Because in the myopic eye the lens is too convex, while in the hypermetropic eye it is not convex enough. While this is often the case, the fault generally depends on a misshapen eyeball. 158 ESSENTIALS OF HUMAN PHYSIOLOGY. What do you mean by dioptric media ? Transparent bodies which so refract the light that images come to a focus on the retina. What do you mean by intraocular pressure? The tension to which the coats of the eyeball are put by the varying quantity of the humors of the eye. When the tension is increased abnormally it is called glaucoma. What do you mean by the Argyll Robinson pupil ? An abnormal condition of the pupil in which it does not con- tract to light, but does contract when accommodation is carried on. What is nystagmus ? Gowers think that it is due to faulty fixation of the eyeball by the reflexes which generally keep it steady. Either the stimula- tion of the reflexes is insufficient or too great. In albinoes we often have it because of too much stimulation from light. In children blind soon after birth it also comes on before the steadying centres can be developed. Hearing. In the same way that all impulses travelling along the optic nerve are interpreted as light, so are all the impulses travelling along the auditory nerve interpreted as sound. Through how many divisions of the ear does the sound pass ? Three ; the external ear and auditory canal, the middle ear, which is shut off from the auditory canal by the tympanic mem- brane, and the labyrinth. HEARING. 159 What is the purpose of the external ear ? To collect sound. What is the function of the auditory canal ? By circumscribing the air it increases its vibrations. What is the function of the cerumen of the external ear? To catch foreign bodies which might otherwise enter. What is the function of the tympanic membrane ? It receives the vibrations of the air in the auditory canal, trans- mitting them to the bones of the middle ear. For what purpose is the tympanic membrane sloped from outward inward? By this means it more readily responds to sounds of varying character and can be of greater dimensions. By what means are the vibrations of sound transmitted after leaving the tympanic membrane ? Three small bones known as the malleus, incus, and stapes join together, and reach from the membrane to a secondary membrane which covers the oval window leading into the vestibule of the internal ear; the malleus is attached to the tympanic membrane, while the stapes is in contact with the oval window. What is the function of the stapedius muscle ? It is attached to the stapes, and when it contracts pulls that bone away from the oval window, otherwise a loud sound might jam the bone into the oval window and produce deafness. 160 ESSENTIALS OF HUMAN PHYSIOLOGY. What is the function of the tensor tympani muscle? By drawing the handle of the malleus internally it increases the tenseness of the tympanic membrane and prevents it from vibrating too much to sounds of great intensity. What is the function of the laxator tympani muscle? It draws the handle of the malleus outward, and relaxes the tympanic membrane. What is the function of the Eustachian tube ? It communicates with the pharynx and opens into the middle ear back of the tympanic membrane, affording vent by which, when the drum is driven in, some of the air may escape. It equalizes the pressure within and without. Is the Eustachian tube constantly open? No, it is not; if it were, the various sounds in the mouth would produce sounds in the ear. In what way is sound transmitted, after passing through the ossicles, to the terminal filaments of the audi- tory nerve ? Through the semicircular canals and the spiral staircase. What fills the semicircular canals? A liquid known as the endolymph. In what manner does the endolymph receive impulses from the exterior ? The endolymph is in direct contact with the membrane which covers the oval window, and when the stapes strikes against this membrane it produces vibrations which are taken up by the endo- lymph. In what way do the nerves end in the semicircular canals ? In peculiar epithelioid cells, to which are attached fine hair-like processes. What are the functions of the otoliths ? These small calcareous masses are set in motion by the vibra- THE VOICE AND SPEECH. 161 , tions of the endolymph and come in contact with the endings of the nerves, producing impulses. The function of those nerve fibres which run to the cochlea is not clearly understood. What function have the semicircular canals other than hearing1 ? They appear to govern equilibrium, for if injured the animal immediately loses its balance. When the horizontal canal is divided the animal rolls its head from side to side. When one of the vertical canals is cut the head moves up and down. Does section of the semicircular canals destroy the power of hearing? No; it influences it very slightly. What is the function of the organ of Corti? It is not distinctly known, but it was supposed to be especially developed in persons with musical tendencies, till it was found that the pig possessed them in a highly developed state. As nerve filaments end in these rods, it has been supposed that each set of rods responds to a certain set of notes. What differences in sound can the ear distinguish ? Loudness, pitch, and quality. The judging of the distance from, which a sound is transmitted is purely a matter of training. The Voice and Speech. With scarcely any exception all air-breathing vertebrates possess some arrangement for the production of sound in some part of the respiratory apparatus. In some animals various modifications of this sound are produced. In man its modifications are so great as to permit of speech. In what way is the voice or sound produced ? By an expiratory blast of air being forced through the narrow opening at the top of the windpipe, called the glottis. The glottis, it will be remembered, lies in the lower part of the larynx and is bounded on each side by thin membranous bands, which, extend- ing from side to side, vibrate as the air rushes over them. For this reason, opening of the trachea prevents speech, since all the air rushes out of the opening rather than over the cords. 162 ESSENTIALS OF HUMAN PHYSIOLOGY. What are the chief organs of the voice? The vocal cords. These are governed by the muscles of the larynx.1 What is the function of the larynx ? It acts as a cavity in which the vocal cords may produce the voice. What is the function of the thyroid and cricoid cartilages? The function of these two cartilages is chiefly for the purpose of affording stiff walls around the vocal apparatus for the sake of protection and attachment. The thyroid cartilage forms an in- complete ring around the larynx, and covers only the front portion and sides. The cricoid cartilage, on the other hand, is a complete ring, the back part of the ring being broader than the front. What is the function of the arytenoid cartilages ? They are situated on the top of the back portion of the cricoid cartilage and are movable upon it, forming a place for the inser- tion of certain muscles concerned in speech. What are the intrinsic muscles of the larynx? They are those which have a direct action on the vocal cord, and are nine in number—four pairs and a single muscle: two crico-thyroids, two thyro-arytenoids, two posterior crico-arytenoids, two lateral crico-arytenoids, and one arytenoid muscle. What are the functions of these muscles ? When the crico-thyroids contract they rotate the cricoid on the thyroid cartilage in such a manner that the upper and back part of the former, and of necessity the arytenoid cartilages on the top of the cricoid cartilage, are tipped backward, while the thyroid is inclined forward. The result of this is that the vocal cords being attached in front to the thyroid cartilage and posteriorly to the cricoid cartilage are put on the stretch. The thyro-arytenoid muscles have an opposite action, for they pull the thyroid back- ward and the arytenoid and the upper and back part of the cricoid 1 For the anatomy of the larynx and those portions of the body concerned in speech, see an anatomical text-book. THE VOICE AND SPEECH. 163 cartilages forward, thus relaxing the vocal cords. The posterior crico-arytenoids dilate the glottis and separate the vocal cords by an action on the arytenoid cartilage. When they contract they pull together the outer angles of the arytenoid cartilages in such a manner as to rotate the latter at their joint with the cricoid, and to throw asunder their anterior angles to which the vocal cords are attached. What muscles oppose these posterior crico-arytenoid muscles ? The lateral crico-arytenoids, which, pulling in the opposite direction from the other side of the axis of rotation, have, of course, exactly the opposite effect, and enclose the glottis. The arytenoid muscle may also close the glottis almost completely, by pulling together the upper parts of the arytenoid cartilages, between which it extends. What is the nervous mechanism of the voice ? The sensory filaments in the pneumogastric give the glottis that acute sensibility which prevents the ingress of foreign bodies or noxious gases into the air-passages. The superior laryngeal branch of the vagus and the inferior laryngeal branch, or the re- current nerve, cooperate not only with the pneumogastric in the closure of the glottis which excludes foreign bodies, but also in the protection and regulation of the voice. The inferior laryn- geal nerve governs the contraction of the muscles that vary the tension of the vocal cords, while the superior laryngeal conveys to the mind the sensations of the state of these muscles, which is absolutely necessary for their intelligent guidance. What three properties are possessed by the human voice ? Quality, pitch, and intensity. Over how wide a musical range does the human voice extend 1 Including all forms of voice, about three and one-half octaves; but of this wide range a single individual can rarely sing more than two octaves. 164 ESSENTIALS OF HUMAN PHYSIOLOGY What difference exists between the notes of the female voice and those of the male ? The lowest note of the female voice is about an octave higher than the lowest note of the male voice. The highest note of the female voice is about an octave higher than the highest note of the male. In what portion of the vocal apparatus is the variation in sound produced which results in speech ? Not in the larynx, but in the mouth and nose, by means of the teeth, tongue, and lips. What sound do we have when speech is not accompanied by the action of the vocal cords ? Only a whisper. What effect upon sound has approximation of the vocal cords? The sound emitted is high pitched in character, while non- approximation of the cords produces sound of greater volume, but of lower pitch. The pitch does not depend, however, absolutely on the approximation or non-approximation of the cords, but more upon the tensity of the cords themselves. What is the function of the epiglottis in regard to sound ? When pressed down so as to cover the cavity of the larynx it serves to render the notes deeper in tone, and, at the same time, somewhat fuller in quality. What is aphasia ? The partial or complete loss of the power of articulate speech from causes arising in the cerebrum. What is the difference between aphasia and aphonia ? Aphasia is the derangement of the mental functions immediately connected with word-thought, while aphonia is the term applied to the voicelessness of laryngeal disease. THE SYMPATHETIC NERVE. 165 What is the term aphaemia applied to? It is usually used to signify a condition of speechlessness due to inability to execute the normal movements of the mouth and tongue. This condition is sometimes called ataxic aphasia. Does a patient who is aphasic still have the power to think, and does he still remember words ? Yes; and he, therefore, can express himself in writing. What do you mean by the term amnesic aphasia? It is the condition in which the idea is present but the word is wanting, although articulation is “ at the service of the word.” The movements in this condition are correct, so far as speech is concerned, but the patient cannot think of the word to speak it. This condition is often seen in old persons to a slight extent, and is called amnesia senilis. What is paraphasia ? The inability to connect rightly ideas with the proper words to express them, so that instead of giving expression to the ideas the sense may be inverted. What is agrammatism ? The inability to form the words grammatically and arrange them in sentences. What is bradyphasia ? A pathological slowness of speech. The Sympathetic Nerve. It will be remembered that the sympathetic system contains a very large number of non-medullated nerve fibres, and consists of a double gangliated prevertebral cord, one on each side of the vertebral column. What are the rami communicantes ? The nerves given off by the spinal nerves to the sympathetic cord. Each spinal nerve does this. 166 ESSENTIALS OF HUMAN PHYSIOLOGY. What do you mean by the cephalic, dorsal, and abdominal portions of the sympathetic? Those portions which govern these areas. In the head the cephalic portion anastomoses with the cranial nerves to a great extent. The abdominal portion supplies the abdominal organs. What are the functions of the sympathetic ? First, the independent functions as represented by the automatic cardiac ganglia, the mesenteric plexus of the intestine, and the plexuses of the uterus, Fallopian tubes, ureters, and lymph and bloodvessels. They are independent in that they are capable of acting without any impulses from higher centres, but they may also be governed by the spinal centres under some circumstances. Second, the dependent functions which are governed by centres, as, for example, the sensory fibres of the splanchnics. What is the function of the cervical sympathetic ? It contains (1) pupil-dilating fibres which, according to Budge, arise from the spinal cord and run through the upper two dorsal and lowest cervical nerves into the cervical sympathetic, which conveys them to the head. What does the cervical sympathetic also supply ? (2) Motor fibres for Muller’s smooth muscle of the orbit, and partly for the external rectus muscle of the eye. It also supplies (3) vaso-motor branches for the outer ear and the side of the face, tympanum, iris, choroid, retina in part, the oesophagus, larynx, thyroid gland, and fibres for the vessels of the brain and its mem- branes ; (4) secretory and vaso-motor fibres for the salivary glands. (5) Sweat secretory fibres are given off, as are also secretory fibres to the (6) lachrymal glands, according to Wolferz and Demtschenko. What are the functions of the thoracic and abdominal sympathetic ? (1) The sympathetic portion of the cardiac plexus, which receives accelerating fibres for the heart from the lower cervical and first thoracic ganglion. (2) The cervical sympathetic and the splanch- nics contain fibres which, when their central ends are stimulated, excite the cardio-inhibitory centre in the medulla. GENERATION AND DEVELOPMENT 167 Give an example of this. If an animal be struck sharply on the belly, over the solar plexus, death may result from cardiac stoppage due to reflex inhibition. What is the splanchnic ? The splanchnic is a division of the sympathetic, and contains vaso-motor filaments. All the vaso-motor nerves do not run through the cord, but some of them leave the cord high up and pass into the sympathetic. These nerve filaments in the splanch- nics govern the bloodvessels of the abdomen very largely. The splanchnic also contains vaso-motor fibres which supply the kidneys. What effect has section of the cervical sympathetic, or its rami communicantes, on the pupil ? It causes contraction of the pupil. What other effect has section of the cervical sympathetic ? It causes increased fulness of the bloodvessels on that side, the eyelids are not held well apart, while the eyeball is sunken and retracted. Sometimes unilateral atrophy of the face comes on. If this section be performed in young growing animals, hypertrophy of that ear and side of face occurs, owing to the increased blood supply and other trophic changes. What is the effect of stimulation of the cervical sympa- thetic ? It causes dilatation of the pupil, and occasionally hyperidrosis or profuse sweating of that side of the head. There is also pro- trusion of the eyeball, and the eyelids are held wide open. The eyeball, instead of being sunken, as after section, is in a condition of exophthalmos. GENERATION AND DEVELOPMENT. What do you mean by generation and development ? The first term signifies the original cause of growth, while the second term signifies the manner of growth after it is once begun. 168 ESSENTIALS OF HUMAN PHYSIOLOGY. They consist of two ovaries, two Fallopian tubes or oviducts, lhe uterus, and a canal known as the vagina. What is the function of the ovaries ? The formation of the ova or eggs. What is the function of the Fallopian tubes or oviducts? The conduction of the ova from the ovaries to the uterus. What is "he function of the uterus ? It is a cavity in which, if impregnated, the ovum is retained until it is fully developed and capable of maintaining its life inde- pendent of the parent. What is the function of the vagina ? It is the canal which receives the male generative organ, the penis, in the act of copulation, and is the passage through which the foetus is discharged. Describe the ovaries. They are two oval bodies situated in the cavity of the pelvis, one on each side, inclosed in the folds of the broad ligaments. Each ovary measures about an inch and a half in length and three- quarters of an inch in width. They are about half an inch in thickness, and are attached to the uterus by a narrow fibrous cord, the ligament of the ovary, and more slightly to one of the fimbriae of the Fallopian tubes. They are enveloped by a dense fibrous tissue. They are covered on the exterior by the germ epithelium. The inner substance, or stroma, is a soft fibrous tissue containing, imbedded in it, a number of vesicles in various stages of develop- ment. What are these vesicles called ? Graafian vesicles. Generative Organs of the Female. GENERATION AND DEVELOPMENT. 169 In what way do the Fallopian tubes grasp the ovule when it is expelled from the ovary? By means of their fimbriated extremities, which are in constant ciliary movement. Describe the formation of the ovule in the ovary. The vesicles in the stroma gradually approach the surface until they project above it. Each follicle or vesicle is covered by an external membranous envelope lined with a layer of nucleated cells, the membrana granulosa. This follicle contains liquid full of small microscopic bodies, with the ovule nearly in its centre, unless the follicle is fully matured when it comes in contact with the membrana granulosa. What is the discus proligerus ? A granular zone of the nucleated cells of the membrana granu- losa, which is heaped around about the ovule. What is the size of the human ovule? About of an inch. What is the zona pellucida or vitelline membrane ? The investment of the ovule, and it adheres closely to the discus proligerus. What lies within the zona pellucida ? The yelk or vitellus, which is composed of granules and globules of various sizes. What arrangement have these globules ? The largest are at the periphery, the smallest are at the centre. What does the yelk or vitellus contain? The germinal vesicle or the vesicula germinativa. What does this germinal vesicle contain? At its periphery, at the point nearest the yelk, it contains the germinal spot or the macula germinativa. These are all the parts of the Graafian follicle. 170 ESSENTIALS OF HUMAN PHYSIOLOGY. Does the formation of Graafian follicles go on constantly during the child-bearing part of life ? Yes. What do you mean by the discharge of the ovule ? When the follicle is ripe and has reached the surface of the ovary, the follicular wall becomes thinner and finally bursts. The ovule and its fluid surroundings escape on the surface of the ovary, which is grasped by the Fallopian tube, down which the ovule travels. Is there any difference in the periodicity of the maturity of the ovule in the different varieties of animals ? Yes; in human beings it is once in every twenty-eight days, while in the common fowl it is constant. What is the difference between the ovule and the ovum ? The term ovule is ordinarily applied to the egg previous to impregnation, while the ovum is the fecundated ovule. What is menstruation ? It is regarded by most physiologists as the flow of blood accom- panying the discharge of a ripened ovule. The rupture of a follicle is not necessarily accompanied by menstruation, neither is menstruation necessarily followed by ovulation. Does rupture of the follicle take place before or after the flow ? In most cases before or at the beginning; more rarely at the middle or end of menstruation. Describe the menstrual discharge. It is a thin, sanguinolent fluid having a peculiar odor, and consists of blood, epithelium, the mucus of the uterus and vagina, and the remains of the mucous membrane lining the uterus. What is this mucous membrane called? The decidua menstrualis, which is developed to perfection just before the menstrual flow and then thrown off. 171 GENERATION AND DEVELOPMENT. Can menstruation be regarded as a hemorrhage ? No; it can not. It is merely a destructive process whereby the membrane which was prepared for receiving a fecundated ovule is thrown off. At what time of life does menstruation begin and end in the temperate zone ? It begins at twelve or fourteen years of age, and ceases at a period between forty and fifty. Does menstruation ever occur during pregnancy, or in nursing women? Rarely; but such cases are on record. What is the corpus luteum ? At the time of rupture of the Graafian vesicle, a yellowish mass, the corpus luteum, develops itself. It is a round, solid body whose walls, after the rupture, become covered by small buds of flesh- like matter, resembling a granulating wound, and these granula- tions extend above the ovarian surface. Ultimately they become covered, but still go on growing inside the ovary. As pregnancy goes on, the red granulations change to yellow and its consistence becomes firmer. Does the corpus luteum depend for its formation on the effusion of blood which takes place when the follicle ruptures ? Not in the least. Remember this. The corpus luteum is, in reality, a growth of cells from the membrana granulosa. What difference is there in the growth of the corpus luteum of pregnancy and in that of ordinary men- struation ? In pregnancy it remains till gestation is nearly ended. When impregnation does not occur it shortly disappears. The Male Sexual Organs. What is the function of the testicles? They are the organs which secrete portions of the semen. 172 ESSENTIALS OF HUMAN PHYSIOLOGY. What other tissues aid in this secretion? The vesiculae seminales, the prostate gland, and Cowper’s glands. What does the semen consist of? Of the secretion of all these tissues. In what way is the secreting portion of the testicle arranged ? Into two parts, one of which is the body of the testicle inclosed within a tough, fibrous membrane, the tunica albuginea, which is covered externally by a serous membrane, the tunica vaginalis. The second part is the epididymis and vas deferens. What is the vas deferens, and what is its function ? It is the duct of the testicle, about two feet in length. It passes to the lower part of the epididymis, with which it is continuous, where it becomes exceedingly tortuous in its course. Of what does the epididymis consist? Of a single tube about twenty feet long. What are the tuhuli seminiferi ? They make up the parenchyma of the organ. In what way, and from what are the spermatozoids formed? The seminal tubule is limited by an elastic membrane, the mem- branapropria, inside of which are several layers of cells, known as the seminal cells. How many kinds of seminal cells have we ? Two. Those resting quietly, others in a state of active division. The active cells are called the mother cells; and the smaller cells, resulting from their division, the daughter cells or spermatoblasts. The spermatozoids are formed from the spermatoblasts. What is the appearance of the spermatozoid? It consists of a small body or head, to which is attached a cilium, or rapidly moving tail. GENERATION AND DEVELOPMENT. 173 What is the function of the spermatozoids ? They are absolutely needful for impregnation, and it is the sper- matozoids which fecundate the ovule. How does the semen reach the exterior of the body ? It is secreted in the tubules of the testicles, then passes along the vasa deferentia into the vesiculse seminales, and from there into the urethra. What is the function of the seminal vesicles other than the carrying off of the semen ? They secrete some of the liquid in which the spermatozoids float or swim. This is probably their chief function, at least in some animals. What is the function of the prostate and Cowper’s glands? To add the proper liquid to the semen. Of what, therefore, does semen consist? The liquor seminis and the spermatozoids, with detached epi- thelial cells. Development. In what part of the female genital organs does the ovule become fecundated? Most commonly in the upper part of the Fallopian tube. What changes take place in the ovum or the fecundated ovule ? The visible change is a slight amoeboid movement of the proto- plasm of the ovum, which is shortly followed by segmentation, which consists in the repeated subdivision of the cells present. How long does this segmentation last ? It is finished by the time the ovum reaches the uterus. What is seen in the centre of each segment ? A central vesicle, which is the result of the repeated division of another central vesicle, just as the segments themselves are the result of the division of the yelk itself. 174 ESSENTIALS OF HUMAN PHYSIOLOGY. What appearance has the ovum as it enters the uterus ? Owing to the many segmentations, it is granular, and resembles a mulberry. How long1 a time does the passage of the ovum from the ovary to the uterus take? Probably eight or ten days. What is the germinal or blastodermic membrane ? It is a membrane which is formed by the accumulation at the periphery of the yelk of a number of the segments or cells. Owing to their number they are pressed against one another, and become polyhedral in shape. What are the layers of the blastoderm ? The epiblast, mesoblast, and hypoblast. What is the function of the epiblast ? From the epiblast are eventually developed the epidermis and its various appendages, the cerebro-spinal nerve centres, the sensory epithelium of the mouth, and the salivary glands. What are developed from the hypoblast ? The epithelum of the whole digestive canal, and the lining of all the ducts which open into it; the parenchyma of the liver and pancreas, and the epithelium of the respiratory tract. What are developed from the mesoblast ? All the organs not so far mentioned, all the connective tissues, the muscles, the vascular and genito-urinary apparatus, and the entire digestive tract, save its lining epithelium. What is the germinal area ? The position at which the embryo is about to appear. It is at first circular, then pyriform. What is the area pellucida ? A clear, transparent spot, which develops in the centre of the germinal area. GENERATION AND DEVELOPMENT. 175 What is the area opaca ? That portion of the germinal area surrounding the area pellucida. What is the primitive groove ? A shallow longitudinal groove which is the first trace of the embryo. It appears near the back part of the area pellucida. What is the medullary groove ? A more permanent groove which soon replaces the primitive groove. It begins at the anterior part of the area pellucida, and gradually displaces the primitive groove. What are the laminae dorsales ? Two longitudinal elevations which bound the medullary canai* They are folds of the epiblast which grow up and extend over and join each other over the medullary canal, forming it into a closed canal or tube. What is this tube now called? The primitive cerebro-spinal axis. At what portion of the embryo do the laminae dorsales first unite ? About the neck, then the head, and down to the lower ex- tremity. What is the notochord or chorda dosalis ? It is an aggregation of cells from the mesoblast immediately underneath or back of the medullary canal. It extends nearly the whole length of the canal, and occupies the future position of the vertebrae. What are the protovertebrae ? Square segments composed of cells from the mesoblast which appear on each side of the medullary canal along its whole length. What is the “splitting of the mesoblast”? Outside of the protovertebrae the mesoblastic cells are split up into two laminae, known as the parietal and visceral. These laminae form the origin for the walls of the trunk. The parietal lamina is closely connected with the epiblast which adheres closely to the 176 ESSENTIALS OF HUMAN PHYSIOLOGY. hypoblast, and forms the serous and muscular walls of the alimen- tary canal and other parts. What is the somatopleure ? The united parietal lamina and the epiblast. What is the splanchnopleure ? The united visceral layer and the hypoblast. What eventually becomes of the space between the soma topleure and the splanchnopleure ? It forms the pericardium, pleurae, and peritoneum. What are the head and tail folds ? Those folds of the blastoderm which limit the embryo at the head and caudal extremities. Similar folds or depressions mark off the lateral margins of the embryo, which now finds itself entirely separate from the yelk and surrounded by a clear space. What is the last portion of the embryo to become com- pletely separated from the yelk ? The head and caudal extremity are first separated, but the an- terior wall of the belly is not closed by the folds till later. Indeed it is never closed in foetal life, for the umbilicus is the remains of this connection with the yelk. What is the neural cavity ? That cavity formed by the upward growth of the laminae dor- sales. What is the body cavity ? That cavity formed by the downwardly folded blastoderm. What are the visceral plates ? The downwardly folded portions of the blastoderm are known as the visceral plates. What forms the rudiment of the alimentary canal ? The folding in of the splanchnopleure lined by hypoblast pinches off a portion of the yelk-sac inclosing it in the body cavity. GENERATION AND DEVELOPMENT. 177 What is the condition of this rudimentary alimentary canal? It is blind or closed at both ends at this time, while its centre communicates freely with the cavity of the yelk-sac. What is the canal called which permits of this communi- cation ? The vitelline or omphalo-mesenteric duct. This condition divides the yelk-sac into two portions. What is the portion of the yelk-sac outside the body cavity called ? The umbilical vesicle. What is the purpose of the umbilical vesicle ? It affords nutriment for the embryo. In what way does the nutriment reach the embryo? Through the omphalo-mesenteric vessels which ramify in the walls of the yelk-sac. Does this yelk-sac or umbilical vesicle afford food all through pregnancy for the embryo ? In mammalia it lasts only for a short time, the nourishment being derived from the mother. What is the amnion ? Beyond the head and tail folds the somatopleure, coated by epi- blast, rises in folds which grow up and arch over the embryo, anteriorly, posteriorly, and laterally, all directed toward one point over the dorsal surface of the embryo. What is the true amnion ? The inner of the two layers of the somatopleure forms the true amnion. What is the false amnion? The outer layer of the somatopleure. What is the chorion ? It is formed by the coalescing of the inner surface of the original vitelline membrane with the false amnion. 178 ESSENTIALS OF HUMAN PHYSIOLOGY. How is the amniotic cavity formed ? The cavity between the true amnion and the external surface of the embryo becomes a closed space, which is called the amniotic cavity. Does the amnion adhere closely to the embryo ? No, it gradually is distended with fluid which separates it from the embryo. What is this fluid called, and what is its function ? The liquor amnii, which increases as pregnancy goes on. This forms a yielding cushion-like support for the embryo, protecting it from injury and gradually distends the neck of the uterus in parturition. What is the allantois ? It is a highly vascular growth, arising from the hinder portion of the peritoneal cavity, which gradually pushes its way out through the amniotic folds, attaching itself to the outer layer of the amnion (false amnion). In other words, it becomes attached to the chorion, in mammals in one spot, in birds all over the chorion. What is formed at this point? By the interlacing of these vessels with those of the mother the placenta is developed. Of what does the chorion now consist ? Three-layers: 1st, the vitelline membrane; 2d, the outer layer of the amniotic fold; 3d, the allantois. What are the villi of the chorion? Small processes on its surface which soon become vascular, particularly so in the region of the future placenta, so as to dip between the maternal vessels. What changes take place in the uterine mucous membrane during this time ? The follicles become tortuous and enlarged, while the epithe- lial layers increase in amount. THE DEVELOPMENT OF ORGANS. 179 What is the result of this increase in the uterine mucous membrane ? It makes up the membrana decidua. Into how many divisions are the portions of the membrana decidua divided? Three: The decidua vera, decidua reflexa, and the decidua serotina What is the function of these three divisions ? The vera lines the cavity of the uterus; the reflexa grows up around the ovum and forms an investment for it; while the sero- tina becomes especially developed in connection with the villi of the chorion. Remember, by the third month the vera and reflexa come in contact, and can no longer be distinguished one from the other. What is the function of the placenta ? It is an organ by which the gaseous and nutritive changes take place between the maternal tissues and the embryo. The placenta has, therefore, a foetal part and a maternal part. THE DEVELOPMENT OF ORGANS. Vertebral Column and Cranium. How are the vertebral column and cranium developed? The notochord or chorda dorsalis consists primarily of soft cellu- lar cartilage which is gradually inclosed in a membranous sheath, which after a time becomes fibrous and has transverse annular fibres. The protovertebrae (see page 154) send processes downward and inward to surround the notochord, and also upward between the medullary canal and the epiblast covering it. In the former situation the cartilaginous bodies of the vertebrae make their ap- pearance, in the latter their arches which inclose the neural canal. The vertebrae do not exactly correspond in their position with the protovertebrae, but each permanent vertebra is developed from the contiguous halves of the protovertebrae. The cranium is developed from a prolongation of the vertebral 180 ESSENTIALS OF HUMAN PHYSIOLOGY. column, and is formed long before the facial bones. It is formed of one mass, the cerebral capsule, the chorda dorsalis being con- tinued into its base and ending there with a tapering point. In what way is the dorsal portion of the body formed ? The muscles and integument of the back, with the exception of the epiderm, which is developed from the epiblast, are developed from the musculo-cutaneous plate which is formed by the dorsal portion of the protovertebrae. What is developed from the ventral portion of the proto- vertebrae ? They give rise to the vertebrae and the heads of the ribs, but the outer part of each protovertebra gives rise to a spinal ganglion and nerve-root. What is the condition at this time of the chorda? It is inclosed in a case, formed by the bodies of the vertebrae, and gradually wastes and disappears. How are the body cavities formed? The dorsal lamince coalesce at the back and complete, by their union, the spinal canal, and the visceral laminae coalesce anteriorly and thus form the thoracic and abdominal cavities. An analogous process occurs in the facial and cervical regions, but the inclosing laminae are cleft. When these clefts fail to unite in the median line cleft-palate or harelip results. Extremities. In what way are the extremities developed ? They appear in the form of leaf-like elevations from the parietes of the trunk at points where more or less of an arch will be pro- duced for them within. How is the heart developed ? It makes its first appearance as a solid mass of cells of the splanchnopleure. A cavity is hollowed out of the centre, and Heart and Bloodvessels THE DEVELOPMENT OF ORGANS. 181 those detached cells float about in a liquid which soon begins to move about under the pulsations of the embryonic heart. How are the bloodvessels developed ? In the formation of the large vessels masses of embryonic cells are arranged in longitudinal form and hollowed out in much the same manner as the heart, the cells of the heart cavity and blood- vessel cavities forming corpuscles. The capillaries seem to be formed of cells arranged end to end in single line and hollowed like a pipe-stem. Nervous System. How is the nervous system developed? All the spinal nerves are derived from the mesoblast, as are also the cranial nerves, except the optic and olfactory, which are out- growths of the anterior cerebral vesicles. The sympathetic system is also developed from the same mesoblastic layer. Have the spinal cord and brain the same origin as the spinal nerves ? Yes. They arise from the epiblast for the gray matter and for the white matter. From what is the spinal cord developed ? Out of the primitive medullary tube which results from the folding in of the dorsal laminae. How is the gray matter formed ? The tube is narrowed in one diameter so that the canal becomes narrow and oval in shape, and finally the two opposite sides unite in the centre of the slit, while the attachments of the two sides at the top and bottom of the canal decrease in thickness, and finally separate. The white matter is derived from the surrounding meso- blast and grows up around the gray columns. The fissures are formed by the separating at the top and bottom of the tube already described. What do you mean by the cerebral vesicles ? A widening out of the medullary canal very early in embryonic life. 182 ESSENTIALS OF HUMAN PHYSIOLOGY How many cerebral vesicles have we? Three. What is the purpose of each ? From the first anterior vesicle are budded off the two primary optic vesicles, and the rudiments of the hemispheres appear in the form of two outgrowths at a higher level. The middle vesicle gives off the rudiments of the corpora quadrigemina, the crura cerebri, and the aqueduct of Sylvius. The posterior vesicle gives off the rudiments of the cerebellum, pons Varolii, the medulla oblongata, and auditory nerve. Eye. From what is the eye developed ? The anterior cerebral vesicle, which sends out a smaller vesicle on each side, the primary optic vesicles, which are hollow. The stalks which attach the vesicles to the original vesicle form the optic nerves. After this the formation of the lens and qpfo’c cups, or secondary optic vesicles, begins. How is the lens formed ? By a thickening of the epiblast, which indents the extremity of the primary optic vesicle and pushes it back till the front wall of the vesicle is in contact with the posterior wall, and the cavity of the vesicle is thereby obliterated. What does this front wall, which has been pushed back, form ? The retina. What does the back wall form ? The pigment layer of the choroid. The margins of the cups grow up around the lens everywhere except at the lower part, by the optic nerve, where a fissure remains. What is this fissure called ? The choroidal fissure. THE DEVELOPMENT OF ORGANS. 183 What is its purpose ? Through it the mesoblast, which forms the connective tissue of the eye, finds an entrance into the cavity of the eye. Ear. How is the ear developed ? Early in embryonic life a depression occurs on each side of the surface of the head, which is covered by a membrane, the primary otic vesicle. What is the purpose of this vesicle? It develops the membranous labyrinth of the internal ear. The surrounding mesoblast gives rise to the various bony and carti- laginous parts inclosing the membranous labyrinth, the bony semicircular canals, etc. The mesoblast also develops the auditory nerve. Nose. How is the nose developed ? It originates, like the eyes and ears, in a depression of the superficial epiblast at each side of the fronto-nasal process, and these cavities gradually grow back till they reach the cavity of the mouth. Alimentary Canal and Organs. In what way is the alimentary canal developed ? It results from the folding in of the splanchnopleure, and is at first straight and parallel to the vertebral column. It is connected with the omphalo-mesaraic duct, a point which corresponds with the lower segment of the ileum, but the duct atrophies and usually disappears about the fourth month. The attachment is at first very broad, and only a thin stratum of mesoblast separates the hypoblast of the canal from the notochord and protovertebrae; but it subsequently attenuates and becomes the mesentery. In the fourth month the part connected with the umbilical vesicle loops forward. The part above the umbilical opening becomes the 184 ESSENTIALS OF HUMAN PHYSIOLOGY. small intestine, and the part below almost wholly the large in- testine. The limit between the two is soon indicated by a projection, the caecum. The intestine separates from the abdominal wall, the remains of the attachment appearing at the third month, and sometimes later, as a thread-like appendage to the lower part of the ileum. Convolutions then begin to form, and an enlarge- ment in the region of the liver, which is the stomach. In what way is the posterior opening in the intestine formed ? By the establishment of a communication between the cloaca, or tube common to the gut and allantois, and a depression outside of the body at about the sixth or seventh week. At the same time a septum, which is the future perineum, separates the intestine from the organs forming the allantois. The mouth is formed in the same manner. In what way are the salivary glands, the pancreas, and the liver developed? The liver commences as a projection formed by two primitive hepatic ducts, which divide and subdivide. At the periphery of the ducts are solid masses of cells which proceed from the hypo- blast. The mass of the gland is developed from the mesoblast. The liver secretes as early as the third month. The pancreas is also formed from the mesoblast, as are also the salivary glands. The lining of their ducts is, however, derived from the hypoblast. The Foetal Circulation. Describe the foetal circulation ? The blood in the placenta, aerated and well nourished, passes up the umbilical vein to the navel, where it enters the body of the foetus, and, after a short course, reaches the liver, where it is split up into two streams, one of which supplies the lobes of the liver, while the other passes through the ductus venosus, which lies in the longi- tudinal fissure of the liver, into the inferior vena cava and right auricle of the heart, but instead of passing into the right ventricle it is directed by the Eustachian valve along the back of the auricle THE DEVELOPMENT OF ORGANS. 185 to the foramen ovale, and immediately enters the left auricle; the left auricle, contracting, propels it into the left ventricle, which drives it into the general circulation. What is the difference in the circulation of blood in the inferior vena cava from that of the superior vena cava? The blood returning from the head, or superior vena cava, passes into the right auricle and enters the right ventricle (which the blood from the inferior vena cava does not). When the right ventricle contracts the blood is driven into the pulmonary artery, but instead of being distributed through the lungs it is directed through a channel given off by the left pulmonary artery, known as the ductus arteriosus, into the aorta just beyond the point where the left subclavian is given off from that vessel. The right ventricle and the left ventricle may, therefore, be said to drive the blood through the general circulation in foetal life. As the result of this, however, it will be seen that in the aorta we have blood, half of which is aerated and half of which is not. In what way does the blood return to the placenta to be nourished and oxygenated ? It passes through the descending aorta, the common iliacs, and the umbilical artery, by which it reaches the placenta. What changes take place in the circulation at birth ? Respiration is commenced, the lungs become expanded, and, in consequence of this, the pulmonary vessels permit the blood to traverse them freely. The ductus arteriosus being no longer required, contracts and shrivels up, but remains as a fibrous cord. At the same time the detachment of the placenta leads to the im- mediate arrest of the flow of blood from the umbilical arteries, and no flow passes along the umbilical vein. The ductus venosus contracts, the currents of the superior and inferior vena cava mix in the right side of the heart, and the Eustachian valve and the foramen ovale become useless. INDEX. Abducent nerve, 143 Aberration, chromatic, 156 Absorption, 73 Accelerator ganglion of the heart, 37 nerve, 38 Accommodation of eye, 155 Acid-albumin, 20 Action of muscles, 104 Afferent nerves, 114 Agrammatism, 165 Albumen, 19 Albuminous foods, 102 Alimentary canal, development of, 176, 183 Alkali-albumin, 20 Allantois, 178 Amnesic aphasia, 165 Amnion, 177 Amylolopsin, 67 Ansemia, 30 Anelectrotonus, 115 Animal heat, 76 source of, 77 Anterior columns, 119 Aperistalsis, 65 Aphtemia, 165 Aphasia, 164 Aphonia, 164 Apnoea, 53 Appendages of the skin, 97 Aqueous humor, 154 Area opaca, 175 pellucida, 174 Argyll Robinson pupil, 158 Arteries, 40 Arterioles, 46 Arytenoid cartilages, 162 Asphyxia, influence of, on blood- pressure, 44 Astigmatism, 156 Auditory canal, 159 nerve, 143 Auricles of the heart, 31 functions of, 32 Auriculo-ventricular valves, 33 Automatism, 124 Axis cylinder, 112 Bile, 71 acids, 71 pigments, 71 Bipolar cells, 119 Bizzozero, blood plaque of, 24 Bladder, 88 Blastoderm, 174 Blind spot, 153 Blood, the, 21 coagulation of, 28 pressure, 42 Bloodvessels, 39 of brain, 136 development of, 181 Body cavity, 176 Boundary zone of kidney, 81 Brain, weight of, 135 Bronchial veins, 49 Buffy coat, 30 Burdach’s column, 120 CALCIUM phosphate in milk, 102 Calyx of kidney, 83 Capacity of the parts of the vascular system, 42. Capillaries, 39 Carbohydrates, 20 Carbonic dioxide, 51 Cardiac nerves, 38 veins, 34 Casein, 20 Cavities of the heart, 31 Centre for deglutition, 131 for respiration, 131 INDEX. 187 Centre for urination, 89 for vomiting, 131 inhibitory, 131 vasomotor, 131 Centrifugal nerves, 113 Centripetal nerves, 113 Cerebellar tract, 124 Cerebellum, 135 Cerebral localization, 138 Cerebrum, 137 Cerumen, 159 Cervical sympathetic, 166 Chemical basis of the body, 17 changes in muscles, 109 composition of the liver, 72 Chiasm, optic, 141 Cholesterin, 71 Choluria, 94 Chorda dorsalis, 175 tympani nerve, 56 Chordae tendineae, 34 Chorion, 177 Choroid coat, 151 Chromatic aberration, 156 Chyluria, 94 Chyme, 63 Ciliary muscle, 151 processes, 151 Cilio-spinal centre, 131 Circulation, 35 through heart, 35 Classification of proteids, 19 Coagulation of the blood, 28 Coats of the arteries, 40 of the eye, 149 Color-blindness, 156 Color of the bile, 71 of the blood, 22 of the urine, 91 Colostrum, 101 Columnae carneae, 35 Columns of the spinal cord, 118 Colloids, 75 Complemental air, 50 Course of the medullary fibres, 118 Cones of the eye, 153 Consciousness, 137 Consistency of muscle, 105 Constituents of the blood, 23 of milk, 102 Contraction of muscles, 99 Convolutions of brain, 138 Cornea, 151 Coronary arteries, 34 Corpora quadrigemina, 133 striata, 134 Corpus luteum, 171 Corpuscles, nerve, 116, 147 red blood, 22 Cortex of kidney, 81 Corti, organ of, 161 Coughing, 54 Coverings of eye, 149 Cranial nerves, 141 Cranium, development of, 179 Cricoid cartilage, 162 Crossed pyramidal tracts, 120, 122, 129 Crura cerebri, 133 Crystalline lens, 154 Crystalloids, 75 DECIDUA menstrualis, 170 reflexa, 179 serotina, 179 vera, 179 Decussation, 129 Defibnnated blood, 29 Definition of physiology, 17 Deglutition, 59, 131 Depressor nerves, 39 Development, 173 of organs, 179 Diabetes insipidus, 94 mellitus, 94 Diapedesis, 24 Diastatic action of saliva, 55, 58 Diffusion, 74 Digestion, 54 Dioptric media, 158 Diplopia, 156 Direct cerebellar tract, 124, 130 pyramidal tracts, 120, 122, 129 Discus proligerus, 169 Ductus arteriosus, 184 venosus, 184 Dysperistalsis, 65 Dyspnoea, 53 EAR, development of, 183 I Efferent nerves, 160 Eggs, 102 Elasticity of muscles, 106 Electrical phenomena of muscle, 107 Electrotonus, 115 Endocardium, 32 188 INDEX. Fmbryonal heart, 31 Emmetropia, 157 Endolymph, 160 Endosmosis, 73 Entopic images, 156 Epiblast, 174 Epididymis, 172 Epiglottis, 164 Euperistalsis, 65 Eupnoea, 53 Eustachian tube, 160 Excretion, 97 Expiration, 49 External ear, 160 Extremities, development of, 179 Extrinsic cardiac nerves, 38 Eye, 149 development of, 182 Eyeball, 150 Eyelashes, 149 FACIAL nerve, 143 Falling energy, 110 Fallopian tubes, 169 Far point, 155 Fats, 21, 102 Feces, amount of, 72 Fecundation, 173 Fibrin, 20, 28 Fibrin-ferments, 28 Fibrinogen, 19 Fibrinoplastin, 28 Filtration, 74 Flesh, 94 Foetal circulation, 184 Fourth ventricle, 129 Functions of the bladder, 88 of the blood, 21 of the coats of the arteries, 40 of the gray matter of cord, 122 of the heart, 32 of the kidneys, 81 of the liver, 71 of the skin, 95 of tracts of cord, 122 of the white matter of cord, 122 of the cardiac valves, 33 Ganglion of the heart, 35 Gases of the blood, 27 of the stomach, 63 Gastric digestion, 62 Gastric juice, 62 Gelatinous substance of Rolando, 120 Generation, 167 Generative organs of female, 168 of male, 171 Germinal area, 174 vesicle, 169 Globulins, 19 Glomerulus, 84 Glosso-pbaryngeal nerve, 143 Glycogen, 70 Glycosuria, 94 Goll’s column, 122 Graafian vesicles, 168 Gray matter of cord, 118 H2EMATIN, 27 Haemoglobin, 27 Haemoglobinuria, 94 Hair, 97 Head folds, 176 Hearing, 158 Heart, the, 31 development of, 189 embryonal, 31 weight of, 31 sounds of, 36 suction of, 32 valves of, 33 Heat, animal, 76 dissipation, 78 production, 78 Heintz’s test, 71 Hemianopsia, 157 Hiccough, 54 Hippuric acid, 93 Humors of the eye, 154 Hypermetropia, 157 Hypoblast, 174 Hypoglossal nerve, 144 T NDIFFERENT point, 116 1 Indol, 67 Inhibitory centre, 131 ganglion of the heart, 35 Injuries of optic nerve, 141 Inspiration, 49 Intestinal digestion, 66 Inversion of images, 154 Iris, 152 Irritability of muscle, 107 INDEX. 189 KATELECTROTONUS, 115 Kidneys, 81 Kinetic energy, 99 Kreatin and kreatinin, 106 I ABYRINTH of kidney, 82 1j Lachrymal glands, 149 Lacteals, 74 Lactic acid, 62 Lactiferous ducts, 98 Laminae dorsalis, 175 Large intestine, function of, 72 Larynx, 162 muscles of, 162 Latent period, 110 Lateral columns of spinal cord, 120 Laughing, 54 Laws of contraction, 116 Laxator tympani muscle, 160 Left heart, 31 Lens, 154 Lesions of spinal cord, 127 Leucin, 67 Leucocythaemia, 30 Ligation of coronary arteries, 34 Liquor amnii, 178 Liver, 68 Locus niger, 132 Macula lutea, 153 Male sexual organs, 150 Malpighian body, 83 Maltose, 55 Mammary glands, 98 Mastication, 59 Maximum stimulation, 110 contraction, 111 Medulla of kidney, 81 oblongata, 128 Medullary groove, 175 Meibomian glands, 149 Meissner’s plexus, 64 Membrana decidua, 179 Membranes of brain and cord, 118 Menstruation, 170 Mesoblast, 174 Metabolism, 98 Microcytes, 24 Milk, 98 Milk-curdling ferments, 63, 67 Milk globules, 100 plasma, 100 Millon’s reagent, 20 Motor ganglion of the heart, 37 nerves, 114 Movements of respiration, 49 of the heart, 35 of the stomach, 60 Multipolar cells, 119 Muscle, ciliary, 149 laxator tympani, 160 plasma, 105 tensor tympani, 160 Muscles, 104 of larynx,163 Musculi papillares, 35 Myopia, 157 Myosin, 19, 105 Nails, 97 Near point, 155 Negative variation, 107,114 Neural cavity, 176 Nerve, abducent, 143 auditory, 143 corpuscles, 116 facial, 143 glosso-pharyngeal, 143 hypoglossal, 144 oculo-motor, 141 olfactory, 141 pathetic, 142 pneumogastric, 144 spinal accessory, 144 sublingual, 144 sympathetic, 165 vagus, 144 Nerves of the kidney, 87 of special sense, 145 of the stomach, 62 of taste, 147 Nervi nervorum, 112 Nervous mechanism of deglutition, 60 of the heart, 37 of heat, 78 of respiration, 53 of speech, 163 of urination, 89 Nervous system, 112 development of, 181 Neuroglia, 118 Nose, development of, 183 Notochord, 175 Number of heart valves, 33 190 INDEX. Nourishment of heart, 34 Nystagmus, 158 OBJECT of respiration, 48 Oculo-motor nerve, 141 Odor of the blood, 22 Olfactory nerve, 141 Olivary body, 129 Optic chiasm, 141 lobes, 133 nerve, 141 thalami, 133 Organ of Corti, 161 Organs of generation, 168 Otoliths, 160 Ovaries, 168 Ovule, 169 Ovum, 170 Oxyhaemoglobin, 22 PANCREATIC digestion, 66 ferments, 67 Papillae of the skin, 95 Paraglobulin, 19 Parapeptone, 63 Paraphasia, 165 Parotid, 55 Parts of the kidney, 86 Pathetic nerve, 142 Pepsin, 62 Peptones, 19 Pericardium, 36 Peristalsis, 64 Perspiration, 79 function of, 79 Pettenkofer’s test, 71 Physical forces of the circulation, 45 Physiology of the spinal nerves, 117 Placenta, 179 Plasma, blood, 23 milk, 100 muscle, 105 Plethora, 30 Pneumogastric nerve, 38, 144 Pons Varolii, 133 Posterior columns of spinal cord, 119 Presbyopia, 15'7 Pressor fibres, 39 Primitive fibril, 112 Primitive groove, 175 Processes, ciliary, 151 Prostate gland, 173 Pro to vertebrae, 175 Proteids, 18 Ptyalin, 58 Pulse, 47 rapidity of, 37 Pupil, 152 Pupillary movement, 152 Pyramids of kidney, 83 of medulla oblongata, 128 Quadrigeminal bodies, 133 Quantity of the bile, 72 Quantity of the blood, 28 of blood expelled, 35 of the saliva, 55 RAMI communieantes, 165 Ranvier’s nodes, 112 Rate of the heart, 37 of respirations, 51 Reaction of muscles, 109 of the blood, 22 of the urine, 91 Recurrent sensibility, 117 Reflex action, 124 inhibiting centre, 126 Refraction, 155 Reserve air, 50 Residual air, 50 Respiration, 48 Respiratory centre, 53, 131 Restiform bodies, 117 Retina, 153 Right heart, 31 Rising energy, 110 Ritti-Valli law, 118 Rods of eye, 153 Rolando, gelatinous substance of, 120 Roots of trifacial nerve, 142 Rouleaux, 25 SALIVA, 54 Salivary centre, 120 digestion, 54 glands, 54 Salts, 94 of urine, 93 Sclerotic coat, 150 Sebaceous glands, 97 Secretion, 97 INDEX. 191 Section of vagi, 39 Segmentation of ovum, 173 Semen, 172 Semicircular canals, 160 Semilunar valves, 33 Sense of sight, 149 of smell, 148 of taste, 147 of touch, 146 Sensibility, 146 Sensory nerves, 114 Serum, blood, 23 Setschenow’s centre, 131 Sighing, 54 Sight, 149 Size of the kidneys, 81 Skatol, 67 Skin, 95 Smell, sense of, 148 Sneezing, 54 Sobbing, 54 Somatopleure, 176 Sounds of the heart, 36 Source of animal heat, 76 Special senses, 145 Specific gravity of the blood, 23 of milk, 98 of urine, 90 Speech, 161 centre, 138 Speed of the circulation, 48 Spermatozoids, 172 Spherical aberration, 156 Spinal accessory nerve, 144 nerves, 107 Splanchnic, 167 Splanchnics, influence of, on peristal- sis, 65 Splanchnopleure, 176 Stapedius muscle, 158 Starch, 20 Starches, 102 Starvation, 103 Steapsin, 68 Stimulation of vagus nerves, 38 of accelerator nerves, 39 Stomach, 60 Sublingual nerve, 144 saliva, 55 Submaxillary saliva, 55 Suction power of heart, 32 Sudoriferous glands, 96 Sugar, 20 Summation, 111 Sweat, 96 Sympathetic, 56 nerve, 165 TACTILE sensibility, 146 Tail folds, 176 Taste, 147 buds, 147 goblets, 147 nerves of, 148 of the blood, 23 Temperature of the blood, 23 Tensor tympani muscle, 160 Testicles, 171 Tests for proteids, 20 Tetanus, 111 Thyroid cartilage, 162 Tidal air, 50 Tractus intermedio-lateralis, 119 Transference, 124 Trifacial nerve, 142 Trommer’s test, 21 Trypsin, 67 Tubes, Fallopian, 168 Tubuli seminiferi, 172 uriniferi, 83 Tiirck’s columns, 122 Tympanic membrane, 159 Tyrosin, 67 UMBILICAL veins, 185 vesicle, 176 Unipolar cell, 119 Urea, 92 Ureters, 87 Uric acid, 93 Urinse potus, cibi, and sanguinis, 91 Urine, 90 Uterus, 168 VAGINA, 168 Vagus nerve, 38,144 Valves of the heart, 33 of the veins, 41 Variations in the blood, 23 Vasa recta, 86 Vas deferens, 172 Vasomotor centre, 43,131 nerves, 43 Vegetable foods, 102 Veins, 37 cardiac, 34 192 INDEX. Ventricles of the heart, 31 weight of, 31 Vernix caseosa, 97 Vertebrae, development of, 179 Vesiculae seminales, 172 Vesicular columns of Clark, 119 Visceral plates, 176 Visual purple, 154 Vital capacity, 50 Villi of chorion, 178 Villus, 74 Vitellin, 19 Vitelline membrane, 177 Vitreous humor, 154 Voice, 161 Vomiting, 64 centre, 131 WATER, 91, 94 Weight of brain, 135 of heart, 31 of left ventricle, 31 White blood-corpuscles, 24 matter of the spinal cord, 118 Work of respiratory muscle, 51 V ANTHO-PROTEIC reaction, 20 pellucida, 169 Medical and Surgical Works STANDARD W. B. SAUNDERS, 925 Walnut Street, Philadelphia, Pa. PUBLISHED BY PAGE ♦American Text-Book of Applied Ihera- peiltics 4 ♦American Text-Book of Diseases of Chil- dren 9 ♦American Text-Book of Gynecology ... 8 ♦American Text-Book of Obstetrics ... 5 ♦American Text-Book of Physiology ... 3 ♦American Text-Book of Practice .... 6 ♦American Text-Book of Surgery . . . . 7 Anders'Theory and Practice of Medicine . 31 Ashton’s Obstetrics 28 Atlas of Skin Diseases 12 Ball’s Bacteriology ....... 28 Bastin’s Laboratory Exercises in Botany . 22 Beck’s Surgical Asepsis 26 Boisliniere’s Obstetric Accidents, Emer- gencies, and Operations 23 Brockway’s Physics 28 Burr’s Nervous Diseases 26 Butler’s Materia Medica, Therapeutics, and Pharmacology . . 29 Cerna’s Notes on the Newer Remedies . . 18 Chapman’s Medical Jurisprudence and Toxicology Clarkson’s Histology 14 Cohen and Eshner’s Diagnosis 28 Corwin’s Diagnosis of the Thorax .... 21 Cragin’s Gynaecology . . 28 Crookshank’sText-Book of Bacteriology . 13 DaCosta’s Manual of Surgery 26 De Schweinitz’s Diseases of the Eye ... 15 Dorland’s Obstetrics 26 Frothingham’s Guide to Bacteriological Laboratory Garrigues’ Diseases of Women 20 Gleason’s Diseases of the Ear 28 ♦Gould and Pyle’s Anomalies and Curi- osities of Medicine 3° Griffith’s Care of the Baby 24 Gross’s Autobiography 10 Hampton’s Nursing: its Principles and Practice 2 3 Hare’s Physiology 28 Hart’s Diet in Sickness and in Health . . 22 Haynes’ Manual of Anatomy 26 Heisler’s Embryology 29 Hyde’s Syphilis and Venereal Diseases . . 26 Jackson and Gleason’s Diseases of the Eye, Nose, and Throat 28 Keating's Pronouncing Dictionary of Medicine 10 Keating’s How to Examine for Life In- surance 23 Keen’s Operation Blanks 22 Kyle’s Diseases of Nose and Throat ... 26 Laine’s Temperature Charts 18 PAGE Lockwood’s Practice of Medicine .... 26 Long’s Syllabus of Gynecology 20 MacDonald’s Surgical Diagnosis and Treat- ment 29 McFarland’s Pathogenic Bacteria .... 16 Martin’s Surgery . . . 28 Martin’s Minor Surgery, Bandaging, and Venereal Diseases 28 Meigs’ Feeding in Early Infancy 16 Moore’s Orthopedic Surgery . 29 Mortis’ Materia Medica and Therapeutics 28 Morris’ Practice of Medicine 28 Morten's Nurses’ Dictionary . 24 Nancrede’s Anatomy and Manual of Dis- section -17 Nancrede’s Anatomy ... 28 Norris’ Syllabus of Obstetrical Lectures . 21 Penrose’s Gynecology 31 Powell’s Diseases of Children 28 Pye’s Elementary Bandaging and Surgical Dressing 29 Raymond’s Physiology 26 Rowland’s Clinical Skiagraphy 14 Saundby’s Renal and Urinary Diseases . . 29 ♦Saunders’ American Year-Book of Medi- cine and Surgery 30 Saunders' Pocket Medical Formulary . . 19 Saunders’ Pocket Medical Lexicon .... 19 Saunders’ New Aid Series of Manuals . 25, 26 Saunders’ Series of Question Compends 27, 28 Sayre’s Practice of Pharmacy ...... 28 Semple’s Pathology and Morbid Anatomy 28 Semple’s Legal Medicine, Toxicology, and Hygiene 28 Senn’s Pathology and Treatment of Tu- mors 11 Senn’s Syllabus of Lectures on Surgery . . 21 Shaw’s Nervous Diseases and Insanity . . 28 Starr’s Diet-Lists for Children 24 Stelwagon’s Diseases of the Skin 28 Stevens’ Materia Medica and Therapeutics 18 Stevens’ Practice of Medicine 17 Stewart’s Manual of Physiology 21 Stewart and Lawrance’s Medical Elec- tricity 28 Stoney’s Practical Points in Nursing ... 13 Sutton and Giles’ Diseases of Women . . 26 Thomas’s Diet-List and Sick-Room Dietary24 Thornton’s Dose-Book and Manual of Pre- scription-Writing 26 Thresh’s Water and Water Supplies ... 14 Vierordt and Stuart’s Medical Diagno- sis 12 Warren’s Surgical Pathology 11 Wolff’s Chemistry 28 Wolff’s Examination of Urine 28 The works indicated thus (*) are sold by subscription (not by booksellers}, usually through travelling solicitors, but they can be obtained direct from the office of publication (charges of shipment prepaid) by remitting the quoted prices. Full descriptive circulars of such works will be sent to any address upon application. All the other books advertised in this catalogue are commonly for sale by booksellers in all parts of the United States; but any book will be sent by the publisher to any address (post-paid) on receipt of the price herein given. GENERAL INFORMATION. One Price. One price absolutely without deviation. No discounts allowed, regardless of the number of books purchased at one time. Prices on all works have been fixed extremely low, with the view to selling them strictly net and for cash. An order accompanied by remittance will receive prompt attention, books being sent to any address in the United States, by mail or express, all charges prepaid. We prefer to send books by express when possible, and if sent C. O. D. we pay all charges for returning the money. Small orders of three dollars or less must invariably be accompanied by remit- tance. There are four ways by which money can be sent at our risk, namely: a post-office money order, an express money order, a bank-check (draft), and in a registered letter. Money sent in any other way is at the sender’s risk. Silver should not be sent through the mail. All books, being packed in patent metal-edged boxes, neces- sarily reach our patrons by mail or express in excellent condi- tion. Books in our .catalogue marked “ For sale by subscription only ” may be secured by ordering them through any of our authorized travelling salesmen, or direct from the Philadelphia office; they are not for sale by booksellers. All other books in our catalogue can be procured of any bookseller at the advertised prices, or directly from us. UF handle only our own publications, and cannot supply second-hand books nor the publications of other houses. In every instance the latest revised edition is sent. In ordering, be careful to state the style of binding desired— Cloth, Sheep, or Half-Morocco. A complete descriptive circular, giving table of contents, etc. of any book sold by subscription only, will be sent free on application. Orders. How to Send Money by Mail. Shipments. Subscription Books. Latest Editions. Bindings. Descriptive Circulars. CATALOGUE OF MEDICAL WORKS. 3 For Sale by Subscription. AN AMERICAN TEXT-BOOK OF PHYSIOLOGY. Edited by William H. Howell, Ph. D., M.D., Professor of Physiology in the Johns Hopkins University, Baltimore, Md. One handsome octavo volume of 1052 pages, fully illustrated. Prices: Cloth, $6.00 net; Sheep or Half- Morocco, $7.00 net. This work is the most notable attempt yet made in America to combine in one volume the entire subject of Human Physiology by well-known teachers who have given especial study to that part of the subject upon which they write. The completed work represents the present status of the science of Physiology, particularly from the standpoint of the student of medicine and of the medical practitioner. The collaboration of several teachers in the preparation of an elementary text- book of physiology is unusual, the almost invariable rule heretofore having been for a single author to write the entire book. One of the advantages to be derived from this collaboration method is that the more limited literature necessary for consultation by each author has enabled him to base his elementary account upon a comprehensive knowledge of the subject assigned to him; another, and perhaps the most important, advantage is that the student gains the point of view of a number of teachers. In a measure he reaps the same benefit as would be obtained by following courses of instruction under different teachers. The different standpoints assumed, and the differences in emphasis laid upon the various lines of procedure, chemical, physical, and anatomical, should give the student a better insight into the methods of the science as it exists to-day. The work will also be found useful to many medical practitioners who may wish to keep in touch with the development of modern physiology. The main divisions of the subject-matter are as follows: General Physiology of Muscle and Nerve — Secretion — Chemistry of Digestion and Nutrition— Movements of the Alimentary Canal, Bladder, and Ureter—Blood and Lymph —Circulation—Respiration—Animal Heat—Central Nervous System—Special Senses — Special Muscular Mechanisms — Reproduction — Chemistry of the Animal Bodv. CONTRIBUTORS: HENRY P. BOWDITCH, M. D., Professor of Physiology, Harvard Medi- cal School. JOHN G. CURTIS, M. D., Professor of Physiology, Columbia Uni- versity, N. Y. (College of Physicians and Surgeons). HENRY H. DONALDSON, Ph. D., Head-Professor of Neurology, Univer- sity of Chicago. W. H. HOWELL, Ph. D., M. D., Professor of Physiology, Johns Hopkins University. FREDERIC S. LEE, Ph. D., Adjunct Professor of Physiology, Colum- bia University, N. Y. (College of Physicians and Surgeons). WARREN P. LOMBARD, M. D., Professor of Physiology, University of Michigan. GRAHAM LUSK, Ph. D., Professor of Physiology, Yale Medical School. W. T. PORTER, M. D., Assistant Professor of Physiology, Har- vard Medical School. EDWARD T. REICHERT, M. D., Professor of Physiology, University of Pennsylvania. HENRY SEWALL, Ph. D., M. D., Professorof Physiology, Medical Depart- ment, University of Denver. 4 W. £. SAUNDTTS' For Sale by Subscription AN AMERICAN TEXT-BOOK OF APPLIED THERAPEU- TICS. For the Use of Practitioners and Students. Edited by James C. Wilson, M. D., Professor of the Practice of Medicine and of Clinical Medicine in the Jefferson Medical College. One handsome octavo volume of 1326 pages. Illustrated. Prices; Cloth, $7.00 net; Sheep or Half-Morocco, $8.00 net. The arrangement of this volume has been based, so far as possible, upon modern pathologic doctrines, beginning with the intoxications, and following with infections, diseases due to internal parasites, diseases of undetermined origin, and finally the disorders of the several bodily systems—digestive, re- spiratory, circulatory, renal, nervous, and cutaneous. It was thought proper to include also a consideration of the disorders of pregnancy. 714<? list of contributors comprises the names of many who have acquired dis- tinction as practitioners and teachers of practice, of clinical medicine, and of the specialties. CONTRIBUTORS: Dr. I. E. Atkinson, Baltimore, Md. Sanger Brown, Chicago, Ill. John B. Chapin, Philadelphia, Pa. William C. Dabney, Charlottesville, Va. John Chalmers DaCosta, Philada., Pa. I. N. Danforth, Chicago, Ill. John L. Dawson, Jr., Charleston, S. C. F. X. Dercum, Philadelphia, Pa. George Dock, Ann Arbor, Mich. Robert T. Edes, Jamaica Plain. Mass. Augustus A. Eshner, Philadelphia, Pa. J. T. Eskridge, Denver, Col. F. Forchheimer, Cincinnati, O. Carl Frese, Philadelphia, Pa. Edwin E. Graham, Philadelphia, Pa. John Guiteras, Philadelphia, Pa. Frederick P. Henry, Philadelphia, Pa. Guy Hinsdale, Philadelphia, Pa. Orville Horwitz, Philadelphia, Pa. W. W. Johnston, Washington, D. C. Ernest Laplace, Philadelphia, Pa. A. Laveran, Paris, France. Dr. James Hendrie Lloyd, Philadelphia, Pa. John Noland Mackenzie, Baltimore, Md. J. W. McLaughlin, Austin, Texas. A. Lawrence Mason, Boston, Mass. Charles K. Mills, Philadelphia, Pa. John K. Mitchell, Philadelphia, Pa. W. P. Northrup, New York City. William Osler, Baltimore, Md. Frederick A. Packard, Philadelphia, Pa. Theophilus Parvin, Philadelphia, Pa. Beaven Rake, London, England. E. O. Shakespeare, Philadelphia, Pa. Wharton Sinkler, Philadelphia, Pa. Louis Starr, Philadelphia, Pa. Henry W. Stelwagon, Philadelphia, Pa. James Stewart, Montreal, Canada. Charles G. Stockton, Buffalo, N. Y. James Tyson, Philadelphia, Pa. Victor C. Vaughan, Ann Arbor, Mich. James T. Whittaker, Cincinnati, O. J. C. Wilson, Philadelphia, Pa. The articles, with two exceptions, are the contributions of American writers. Written from the standpoint of the practitioner, the aim of the work is to facili- tate the application of knowledge to the prevention, the cure, and the allevia- tion of disease. The endeavor throughout has been to conform to the title of the book—Applied Therapeutics—to indicate the course of treatment to be pursued at the bedside, rather than to name a list of drugs that have been used at one time or another. While the scientific superiority and the practical desirability of the metric system of weights and measures is admitted, it has not been deemed best to discard entirely the older system of figures, so that both sets have been given where occasion demanded. CATALOGUE OF MEDICAL WORKS. 5 For Sale by Subscription. AN AMERICAN TEXT-BOOK OF OBSTETRICS. Edited by Richard C. Norris, M. D.; Art Editor, Robert L. Dickinson, M. D. One handsome octavo volume of over 1000 pages, with nearly 900 colored and half tone illustrations. Prices: Cloth, $7.00; Sheep or Half-Morocco, $8.00. The advent of each successive volume of the series of the American Text- Books has been signalized by the most flattering comment from both the Press and the Profession. The high consideration received by these text-books, and their attainment to an authoritative position in current medical literature, have been matters of deep international interest, which finds its fullest expression in the demand for these publications from all parts of the civilized world. In the preparation of the “American Text-Book of Obstetrics” the editor has called to his aid proficient collaborators whose professional prominence entitles them to recognition, and whose disquisitions exemplify Practical Obstetrics. While these writers were each assigned special themes for dis- cussion, the correlation of the subject-matter is, nevertheless, such as ensures logical connection in treatment, the deductions of which thoroughly represent the latest advances in the science, ancf which elucidate the best modern methods of procedure. The more conspicuous feature of the treatise is its wealth of illustrative matter. The production of the illustrations had been in progress for several years, under the personal supervision of Robert L. Dickinson, M. D., to whose artistic judgment and professional experience is due the most sumptuously illustrated work of the period. By means of the photographic art, combined with the skill of the artist and draughtsman, conventional illustration is super- seded by rational methods of delineation. Furthermore, the volume is a revelation as to the possibilities that may be reached in mechanical execution, through the unsparing hand of its publisher. Dr. James C. Cameron. Edward P. Davis. Robert L. Dickinson. Charles Warrington Earle. James H. Etheridge. Henry J. Garrigues. Barton Cooke Hirst. Charles Jewett. CONTRIBUTORS: Dr. Howard A. Kelly. Richard C. Norris. Chauncey D. Palmer. Theophilus Parvin. George A. Piersol. Edward Reynolds. Henry Schwarz. “ At first glance we are overwhelmed by the magnitude of this work in several respects, viz. : First, by the size of the volume, then by the array of eminent teachers in this depart- ment who have taken part in its production, then by the profuseness and character of the illustrations, and last, but not least, the conciseness and clearness with which the text is ren- dered. This is an entirely new composition, embodying the highest knowledge of the art as it stands to-day by authors who occupy the front rank in their specialty, and there are many of them. We cannot turn over these pages without being struck by the superb illustrations which adorn so many of them. We are confident that this most practical work will find instant appreciation by practitioners as well as students.”—New York Medical Times. Permit me to say that your American Text-Book of Obstetrics is the most magnificent medical work that I have ever seen. I congratulate you and thank you for this superb work, which alone is sufficient to place you first in the ranks of medical publishers. With profound respect I am sincerely yours, Alex. J. C. Skene. 6 W. B. SAUNDERS' For Sale by Subscription. AN AMERICAN TEXT-BOOK ON THE THEORY AND PRACTICE OF MEDICINE. By American Teachers. Edited by William Pepper, M. D., LL.D., Provost and Professor of the Theory and Practice of Medicine and of Clinical Medicine in the University of Pennsylvania. Complete in two handsome royal-octavo volumes of about 1000 pages each, with illustrations to elucidate the text wherever necessary. Price per Volume : Cloth, $5.00 net; Sheep or Half-Morocco, $6.00 net. VOLUME I. CONTAINS: Hygiene.—Fevers (Ephemeral, Simple Con- tinued, Typhus, Typhoid, Epidemic Cerebro- spinal Meningitis, and Relapsing).—Scarla- tina, Measles, Rotheln, Variola, Varioloid, Vaccinia,Varicella, Mumps,Whooping-cough, Anthrax, Hydrophobia, Trichinosis, Actino- mycosis, Glanders, and Tetanus.—Tubercu- losis, Scrofula, Syphilis, Diphtheria, Erysipe- las, Malaria, Cholera, and Yellow Fever.— Nervous, Muscular, and Mental Diseases etc. VOLUME II. CONTAINS: Urine (Chemistry and Microscopy).—Kid- ney and Lungs.—Air-passages (Larynx and Bronchi) and Pleura.—Pharynx, CEsophagus, Stomach and Intestines (including Intestinal Parasites), Heart, Aorta, Arteries and Veins. —jPeritoneum, Liver,and Pancreas.—Diathet- ic Diseases (Rheumatism, Rheumatoid Ar- thritis, Gout, Lithsemia, and Diabetes.)— Blood and Spleen.—Inflammation, Embolism, Thrombosis, Fever, and Bacteriology. The articles are not written as though addressed to students in lectures, but are exhaustive descriptions of diseases, with the newest facts as regards Causa- tion, Symptomatology, Diagnosis, Prognosis, and Treatment, including a large number of approved formulae. The recent advances made in the study of the bacterial origin of various diseases are fully described, as well as the bearing of the knowledge so gained upon prevention and cure. The subjects of Bacteriology as a whole and of Immunity are fully considered in a separate section. Methods of diagnosis are given the most minute and careful attention, thus enabling the reader to learn the very latest methods of investigation without consulting works specially devoted to the subject. Dr. J. S. Billings, Philadelphia. Francis Delafield, New York. Reginald H. Fitz, Boston. James W. Holland, Philadelphia. Henry M. Lyman, Chicago. William Osler, Baltimore. CONTRIBUTORS: Dr. William Pepper, Philadelphia. W. Gilman Thompson, New York. W. H. Welch, Baltimore. James T. Whittaker, Cincinnati. James C. Wilson, Philadelphia. Horatio C. Wood, Philadelphia. “ We reviewed the first volume of this work, and said: * It is undoubtedly one of the best text-books on the practice of medicine which we possess.’ A consideration of the second and last volume leads us to modify that verdict and to say that the completed work is, in our opinion, the best of its kind it has ever been our fortune to see. It is complete, thorough, accurate, and clear. It is well written, well arranged, well printed, well illustrated, and well bound. It is a model of what the modern text-book should be.”—New York Medical Journal. “ A library upon modern medical art. The work must promote the wider diffusion of sound knowledge.”—American Lancet. “ A trusty counsellor for the practitioner or senior student, on which he may implicitly rely.”—Edinburgh Medical Journal. CATALOGUE OF MEDICAL WORKS. 7 For Sale by Subscription. AN AMERICAN TEXT-BOOK OF SURGERY. Edited by Wil- liam W. Keen, M.D., LL.D., and J. W’illiam White, M. D., Ph. D. Forming one handsome royal-octavo volume of 1250 pages (lox 7 inches), with 500 wood-cuts in text, and 37 colored and half tone plates, many of them engraved from original photographs and drawings furnished by the authors. Prices : Cloth, $7.00 net; Sheep or Half-Morocco, $8.00 net. SECOND EDITION, REVISED AND ENLARGED, With a Section devoted to “The Use of the Rontgen Rays in Surgery.” The want of a text-book which could be used by the practitioner and at the same time be recommended to the medical student has been deeply felt, espe- cially by teachers of surgery; hence, when it was suggested to a number of these that it would be well to unite in preparing a text-book of this description, great unanimity of opinion was found to exist, and the gentlemen below named gladly consented to join in its production. While there is no distinctive Amer- ican Surgery, yet America has contributed very largely to the progress of modern surgery, and among the foremost of those who have aided in developing this art and science will be found the authors of the present volume. All of them are teachers of surgery in leading medical schools and hospitals in the United States and Canada. Especial prominence has been given to Surgical Bacteriology, a feature which is believed to be unique in a surgical text-book in the English language. Asep- sis and Antisepsis have received particular attention. The text is brought wyl 1 up to date in such important branches as cerebral, spinal, intestinal, and pelvic surgery, the most important and newest operations in these departments being described and illustrated. The text of the entire book has been submitted to all the authors for their mutual criticism and revision—an idea in book-making that is entirely new and original. The book as a whole, therefore, expresses on all the important sur- gical topics ol the day the consensus of opinion of the eminent surgeons who have joined in its preparation. One of the most attractive features of the book is its illustrations. Very many of them are original and faithful reproductions of photographs taken directly from patients or from specimens. CONTRIBUTORS: Dr. Charles H. Burnett, Philadelphia. Phineas S. Conner, Cincinnati. Frederic S. Dennis, New York. William W. Keen, Philadelphia. Charles B. Nancrede, Ann Arbor, Mich Roswell Park, Buffalo, N. Y. Lewis S. Pilcher, New York. Dr. Nicholas Senn, Chicago. Francis J. Shepherd. Montreal, Canada. Lewis A. Stimson, New York. William Thomson, Philadelphia. J. Collins Warren, Boston. J. William White, Philadelphia. text'bo°k■ js a fair reflex of the present position of American surgery, we must of,a.v<;ry high order of merit, and that English surgeons will have to look verv aUre S *f they are tO Preserve a position in the van of surgical practice.”— 8 W. B. SAUNDERS' For Sale by Subscription. AN AMERICAN TEXT-BOOK OF GYNECOLOGY, MEDICAL AND SURGICAL, for the use of Students and Practitioners. Edited by J. M. Baldy, M. D. Forming a handsome royal-octavo volume, with 360 illustrations in text and 37 colored and half-tone plates. Prices: Cloth, $6.00 net; Sheep or Half-Morocco, $7.00 net. In this volume all anatomical descriptions, excepting those essential to a clear understanding of the text, have been omitted, the illustrations being largely de- pended upon to elucidate the anatomy of the parts. This work, which is thoroughly practical in its teachings, is intended, as its title implies, to be a working text-book for physicians and students. A clear line of treatment has been laid down in every case, and although no attempt has been made to dis- cuss mooted points, still the most important of these have been noted and ex- plained. The operations recommended are fully illustrated, so that the reader, having a picture of the procedure described in the text under his eye, cannot fail to grasp the idea. All extraneous matter and discussions have been carefully excluded, the attempt being made to allow no unnecessary details to cumber the text. The subject-matter is brought up to* date at every point, and the work is as nearly as possible the combined opinions of the ten specialists who figure as the authors. The work is well illustrated throughout with wood-cuts, half-tone and colored plates, mostly selected from the authors’ private collections. CONTRIBUTORS: Dr. Henry T. Byford. John M. Baldy. Edwin Cragin. J. H. Etheridge. William Goodell. Dr. Howard A. Kelly. Florian Krug. E. E. Montgomery. William R. Pryor. George M. Tuttle. '* The most notable contribution to gynecological literature since 1887, .... and the most complete exponent of gynecology which we have. No subject seems to have been neglected, .... and the gynecologist and surgeon, and the general practitioner who has any desire to practise diseases of women, will find it of practical value. In the matter of illustrations and plates the book surpasses anything we have seen.”—Boston Medical and Surgical Journal. “ A valuable addition to the literature of Gynecology. The writers are progressive, aggressive, and earnest in their convictions.”—Medical News, Philadelphia. “ A thoroughly modern text-book, and gives reliable and well-tempered advice and in- struction.”—Edinburgh Medical Journal. “ The harmony of its conclusions and the homogeneity of its style give it an individuality which suggests a single rather than a multiple authorship.”—Annals of Surgery. “ It must command attention and respect as a worthy representation of our advanced clinical teaching."—American Journal of Medical Sciences. CATALOGUE OF MEDICAL WO EKS. 9 For Sale by Subscription. AN AMERICAN TEXT- BOOK OF THE DISEASES OF CHIL- DREN. By American Teachers. Edited by Louis Starr, M. D., assisted by Thompson S. Westcott, M. D. In one handsome royal-8vo volume of 1190 pages, profusely illustrated with wood cuts, half-tone and colored plates. Net Prices : Cloth, $7.00; Sheep or Half-Morocco, $8.00. The plan of this work embraces a series of original articles written by some sixty well-known paediatrists, representing collectively the teachings of the most prominent medical schools and colleges of America. The work is intended to be a practical book, suitable for constant and handy reference by the practi- tioner and the advanced student. One decided innovation is the large number of authors, nearly every article being contributed by a specialist in the line on which he writes. This, while entailing considerable labor upon the editors, has resulted in the publication of a work thoroughly new and abreast of the times. Especial attention has been given to the latest accepted teachings upon the etiology, symptoms, pathology, diagnosis, and treatment of the disorders of chil- dren, with the introduction of many special formulae and therapeutic procedures. Special chapters embrace at unusual length the Diseases of the Eye, Ear, Nose and Throat, and the Skin ; while the introductory chapters cover fully the important subjects of Diet, Hygiene, Exercise, Bathing, and the Chemistry of Food. Tracheotomy, Intubation, Circumcision, and such minor surgical pro- cedures coming within the province of the medical practitioner are carefully considered. CONTRIBUTORS: Dr. S. S. Adams, Washington. John Ashhurst, Jr., Philadelphia. A. D. Blackader, Montreal, Canada. Dillon Brown, New York. Edward M. Buckingham, Boston. Charles W. Burr, Philadelphia. W. E. Casselberry, Chicago. Henry Dwight Chapin, New York. W. S. Christopher, Chicago. Archibald Church, Chicago. Floyd M. Crandall, New York. Andrew F. Currier, New York. Roland G. Curtin, Philadelphia J. M. DaCosta, Philadelphia. I. N. Danforth, Chicago. Edward P. Davis, Philadelphia. John B. Deaver, Philadelphia. G. E. de Schweinitz, Philadelphia. John Doming, New York. Charles Warrington Earle, Chicago. Wm. A. Edwards, San Diego, Cal. F. Forchheimer, Cincinnati. J. Henry Fruitnight, New York. Landon Carter Gray, New York. J. P. Crozer Griffith, Philadelphia. W. A. Hardaway. St. Louis. M. P Hatfield, Chicago. Barton Cooke Hirst, Philadelphia. H. Illoway, Cincinnati. Henry Jackson, Boston. Charles G. Jennings, Detroit. Henry Koplik, New York. Dr. Thomas S. Latimer, Baltimore. Albert R. Leeds, Hoboken, N. J. J. Hendrie Lloyd, Philadelphia. George Roe Lockwood, New York. Henry M. Lyman, Chicago. Francis T. Miles, Baltimore. Charles K. Mills, Philadelphia. John H. Musser, Philadelphia. Thomas R. Neilson, Philadelphia. W. P. Northrup, New York. William Osler, Baltimore. Frederick A. Packard, Philadelphia. William Pepper, Philadelphia. Frederick Peterson, New York. W. T. Plant, Syracuse, New York. William M. Powell, Atlantic City. B. Alexander Randall, Philadelphia. Edward O. Shakespeare, Philadelphia- F. C. Shattuck, Boston. J. Lewis Smith, New York. Louis Starr, Philadelphia. M. Allen Starr, New York. J. Madison i'aylor, Philadelphia. Charles W. Townsend, Boston. James Tyson, Philadelphia. W. S. Thayer, Baltimore. Victor C. Vaughan, Ann Arbor, Mich Thompson S. Westcott, Philadelphia. Henry R. Wharton, Philadelphia. J. William White, Philadelphia. J. C. Wilson, Philadelphia. 10 IV. B. SAUNDERS' A NEW PRONOUNCING DICTIONARY OF MEDICINE, with Phonetic Pronunciation, Accentuation, Etymology, etc. By John M. Keating, M. D., LL.D., Fellow of the College of Physicians of Phila- delphia ; Vice-President of the American Paediatric Society; Ex-President of the Association of Life Insurance Medical Directors; Editor “ Cyclo- paedia of the Diseases of Children,” etc.; and Henry Hamilton, author of “A New Translation of Virgil’s zEneid into English Rhyme;” co- author of “Saunders’ Medical Lexicon,” etc.; with the Collaboration of J. Chalmers DaCosta, M. D., and Frederick A. Packard, M. D. With an Appendix containing important Tables of Bacilli, Micrococci, Leucoma'ines, Ptomaines, Drugs and Materials used in Antiseptic Sur- gery, Poisons and their Antidotes, Weights and Measures, Thermometric Scales, New Official and Unofficial Drugs, etc. One very attractive volume of over 800 pages. Second Revised Edition. Prices: Cloth, $5.00 net; Sheep or Half-Morocco, $6.00 net; with Denison’s Patent Ready-Refer- ence Index; without patent index, Cloth, $4.00 net; Sheep or Half- Morocco, $5.00 net. PROFESSIONAL OPINIONS. “ I am much pleased with Keating’s Dictionary, and shall take pleasure in recommending it to my classes.” Henry M. Lyman, M. D., Professor of Principles and Practice of Medicine, Rush Medical College, Chicago, III. “ I am convinced that it will be a very valuable adjunct to my study-table, convenient in size and sufficiently full for ordinary use.” C. A. Lindsley, M. D., Professor of Theory and Practice of Medicine, Medical Dept. Yale University ; Secretary Connecticut State Board of Health, New Haven, Conn, AUTOBIOGRAPHY OF SAMUEL D. GROSS, M. D., Emeritus Pro- fessor of Surgery in the Jefferson Medical College of Philadelphia, with Reminiscences of His Times and Contemporaries. Edited by his sons, Samuel W. Gross, M. D., LL.D., late Professor of Principles of Surgery and of Clinical Surgery in the Jefferson Medical College, and A. Haller Gross, A. M., of the Philadelphia Bar. Preceded by a Memoir of Dr. Gross, by the late Austin Flint, M. D., LL.D. In two handsome volumes, each containing over 400 pages, demy 8vo, extra cloth, gilt tops, with fine Frontispiece engraved on steel. Price per Volume, $2.50 net. This autobiography, which was continued by the late eminent surgeon until within three months of his death, contains a full and accurate history of his early struggles, trials, and subsequent successes, told in a singularly interesting and charming manner, and embraces short and graphic pen-portraits of many of the most distinguished men—surgeons, physicians, divines, lawyers, states- men, scientists, etc.—with whom he was brought in contact in America and in Europe; the whole forming a retrospect of more than three-quarters of a century. CATALOGUE OF MEDICAL WORKS. 11 SURGICAL PATHOLOGY AND THERAPEUTICS. By John Collins Warren, M. D., LL.D., Professor of Surgery, Medical Depart- ment Harvard University; Surgeon to the Massachusetts General Hospital, etc. A handsome octavo volume of 832 pages, with 136 relief and litho- graphic illustrations, 33 of which are printed in colors, and all of which were drawn by William J. Kaula from original specimens. Prices : Cloth, $6.00 net; Half-Morocco, $7.00 net. “ The volume is for the bedside, the amphitheatre, and the ward. It deals with things not as we see them through the microscope alone, but as the prac- titioner sees their effect in his patients; not only as they appear in and affect culture-media, but also as they influence the human body; and, following up the demonstrations of the nature of diseases, the author points out their logical treatment.” (A'isw Vorh Medical Journal). “ It is the handsomest specimen of book-making * * * that has ever been issued from the American medical press” (American Journal of the Medical Sciences, Philadelphia). Without Exception, the Illustrations are the Best ewer Seen in a Work of this Kind. “A most striking and very excellent feature of this book is its illustrations. Without ex- ception, from the point of accuracy and artistic merit, they are the best ever seen in a work of this kind. * * * Many of those representing microscopic pictures are so perfect in their coloring and detail as almost to give the beholder the impression that he is looking down the barrel of a microscope at a well-mounted section.”—Annals of Surgery, Philadelphia. PATHOLOGY AND SURGICAL TREATMENT OF TUMORS. By N. Senn, M. D., Ph. D., LL. D., Professor of Practice of Surgery and of Clinical Surgery, Rush Medical College; Professor of Surgery, Chicago Polyclinic; Attending Surgeon to Presbyterian Hospital; Surgeon-in-Chief, St. Joseph’s Hospital, Chicago. One volume of 710 pages, with 515 engravings, including full-page colored plates. Prices: Cloth, $6.00 net; Half-Morocco, $7.00 net. Books specially devoted to this subject are few, and in our text-books and systems of surgery this part of surgical pathology is usually condensed to a de- gree incompatible with its scientific and clinical importance. The author spent many years in collecting the material for this work, and has taken great pains to present it in a manner that should prove useful as a text-book for the student, a work of reference for the busy practitioner, and a reliable, safe guide for the surgeon. The more difficult operations are fully described and illustrated. More than one hundred of the illustrations are original, while the remainder were selected from books and medical journals not readily accessible. “ The most exhaustive of any recent book in English on this subject. It is well illus- trated, and will doubtless remain as the principal monograph on the subject in our language for some years. The book is handsomely illustrated and printed, .... and the author has given a notable and lasting contribution to surgery.”—Journal of American Medical Asso- ciation, Chicago. 12 W. B. SAUNDERS' MEDICAL DIAGNOSIS. By Dr. Oswald Vierordt, Professor of Medicine at the University of Heidelberg. Translated, with additions, from the Second Enlarged German Edition, with the author’s permission, by Francis H. Stuart, A. M., M. D. Third and Revised Edition. In one handsome royal-octavo volume of 700 pages, 178 fine wood-cuts in text, many of which are in colors. Prices: Cloth, $4.00 net; Sheep or Half-Morocco, $5.00 net. In this work, as in no other hitherto published, are given full and accurate explanations of the phenomena observed at the bedside. It is distinctly a clin- ical work by a master teacher, characterized by thoroughness, fulness, and accu- racy. It is a mine of information upon the points that are so often passed over without explanation. Especial attention has been given to the germ-theory as a factor in the origin of disease. This valuable work is now published in German, English, Russian, and Italian. The issue of a third American edition within two years indicates the favor with which it has been received by the profession. THE PICTORIAL ATLAS OF SKIN DISEASES AND SYPHI- LITIC AFFECTIONS. (American Edition.) Translation from the French. Edited by J. J. Pringle, M. B., F. R. C. P., Assistant Phy- sician to, and Physician to the department for Diseases of the Skin at, the Middlesex Hospital, London. Photo-lithochromes from the famous models of dermatological and syphilitic cases in the Museum of the Saint-Louis Hospital, Paris, with explanatory wood-cuts and letter-press. In 12 Parts, at $3.00 per Part. Parts 1 to 8 now ready. “The plates are beautifully executed.”—Jonathan Hutchinson, M. D. (London Hospital). “The plates in this Atlas are remarkably accurate and artistic reproductions of typical examples of skin disease. The work will be of great value to the practitioner and student." —William Anderson, M. D. (St. Thomas Hospital). “ If the succeeding parts of this Atlas are to be similar to Part 1, now before us, we have no hesitation in cordially recommending it to the favorable notice of our readers as one of the finest dermatological atlases with which we are acquainted.”—Glasgow Medical Journal, Aug., 1895. “ Of all the atlases of skin diseases which have been published in recent years, the present one promises to be of greatest interest and value, especially from the standpoint of the general practitioner ”—American Medico-Surgical Bulletin, Feb. 22, 1896. “The introduction of explanatory wood-cuts in the text is a novel and most important feature which greatly furthers the easier understanding of the excellent plates, than which nothing, we venture to say, has been seen better in point of correctness, beauty, and general merit.”—New York Medical Journal, Feb. 15, 1896. “ An interesting feature of the Atlas is the descriptive text, which is written for each picture by the physician who treated the case or at whose instigation the models have been made. We predict for this truly beautiful work a large circulation in alt parts of the medical world where the names St. Louis and Baretta have preceded it.”—Medical Record, N. Y., Feb. 1, 1896. CATALOGUE OF MEDICAL WORKS. 13 PRACTICAL POINTS IN NURSING. For Nurses in Private Practice. By Emily A. M. Stoney, Graduate of the Training-School for Nurses, Lawrence, Mass.; Superintendent of the Training-School for Nurses, Carney Hospital, South Boston, Mass. 456 pages, handsomely illustrated with 73 engravings in the text, and 9 colored and half-tone plates. Cloth. Price, $1.75 net. In this volume the author explains, in popular language and in the shortest possible form, the entire range of private nursing as distinguished from hospital nursing, and the nurse is instructed how best to meet the various emergencies of medical and surgical cases when distant from medical or surgical aid or when thrown on her own resources. An especially valuable feature of the work will be found in the directions to the nurse how to improvise everything ordinarily needed in the sick-room, where the embarrassment of the nurse, owing to the want of proper appliances, is fre- quently extreme. The work has been logically divided into the following sections: I. The Nurse : her responsibilities, qualifications, equipment, etc. II. The Sick-Room: its selection, preparation, and management. III. The Patient: duties of the nurse in medical, surgical, obstetric, and gyne- cologic cases. IV. Nursing in Accidents and Emergencies. V. Nursing in Special Medical Cases. VI. Nursing of the New-born and Sick Children. VII. Physiology and Descriptive Anatomy. The Appendix contains much information in compact form that will be found of great value to the nurse, including Rules for Feeding the Sick; Recipes for Invalid Foods and Beverages; Tables of Weights and Measures; Table for Computing the Date of Labor; List of Abbreviations; Dose-List; and a full and complete Glossary of Medical Terms and Nursing Treatment. “There are few books intended for non-professional readers which can be so cordially endorsed by a medical journal as can this one.”—Therapeutic Gazette, Aug. 15, 1896. “This is a well-written, eminently practical volume, which covers the entire range of private nursing as distinguished from hospital nursing, and instructs the nurse how best to meet the various emergencies which may arise and how to prepare everything ordinarily needed in the illness of her patient.”—American Journal of Obstetrics and Diseases of Women and Children, Aug., 1896. A TEXT-BOOK OF BACTERIOLOGY, including the Etiology and Prevention of Infective Diseases and an account of Yeasts and Moulds, Hsematozoa, and Psorosperms. By Edgar M. Crookshank, M. B., Pro- fessor of Comparative Pathology and Bacteriology, King’s College, London. A handsome octavo volume of 700 pages, with 273 engravings in the text, and 22 original and colored plates. Price, $6.50 net. This book, though nominally a Fourth Edition of Professor Crookshank’s “ Manual of Bacteriology,” is practically a new work, the old one having been reconstructed, greatly enlarged, revised throughout, and largely rewritten, forming a text-book for the Bacteriological Laboratory, for Medical Officers of Health, and for Veterinary Inspectors. 14 IV. B. SAUNDERS A TEXT-BOOK OF HISTOLOGY, DESCRIPTIVE AND PRAC- TICAL. For the Use of Students. By Arthur Clarkson, M. B., C. M., Edin., formerly Demonstrator of Physiology in the Owen’s College, Manchester; late Demonstrator of Physiology in the Yorkshire College, Leeds. Large 8vo, 554 pages, with 22 engravings in the text, and 174 beautifully colored original illustrations. Price, strongly bound in Cloth, $6.00 net. lhe purpose of the writer in this work has been to furnish the student of His- tology, in one volume, with both the descriptive and the practical part of lhe science. 1 he first two chapters are devoted to the consideration of the general methods of Histology; subsequently, in each chapter, the structure of the tissue or organ is first systematically described, the student is then taken tutorially over the specimens illustrating it, and, finally, an appendix affords a short note of the methods of preparation. “We would most cordially recommend it to all students of histology.”—Dublin Medical Journal. “It is pleasant to give unqualified praise to the colored illustrations ; . . . the standard is high, and many of them are not only extremely beautiful, but very clear and demonstra- tive. . . . The plan of the book is excellent.”—Liverpool Medical Journal. ARCHIVES OF CLINICAL SKIAGRAPHY. By Sydney Rowland, B. A., Camb. A series of collotype illustrations, with descriptive text, illustrating the applications of the New Photography to Medicine and Sur- gery. Price, per Part, $1.00. Parts I. to HI. now ready. The object of this publication is to put on record in permanent form some of the most striking applications of the new photography to the needs of Medicine and Surgery. The progress of this new art has been so rapid that, although Prof. Rontgen’s discovery is only a thing of yesterday, it has already taken its place among the approved and accepted aids to diagnosis. WATER AND WATER SUPPLIES. By John C. Thresh, D. Sc., M. B., D. P. H., Lecturer on Public Health, King’s College, London; Editor of the “Journal of State Medicine,” etc. I2mo, 438 pages, illus- trated. Handsomely bound in Cloth, with gold side and back stamps. Price, $2.25 net. This work will furnish any one interested in public health the information requisite for forming an opinion as to whether any supply or proposed supply is sufficiently wholesome and abundant, and whether the cost can be considered reasonable. The work does not pretend to be a treatise on Engineering, yet it contains sufficient detail to enable any one who has studied it to consider intelligently any scheme which may be submitted for supplying a community with water. DISEASES OF THE EYE. A Hand-Book of Ophthalmic Prac- tice. By G. E. de Schweinitz, M. D., Professor of Ophthalmology in the Jefferson Medical College, Philadelphia, etc. A handsome royal- octavo volume of 679 pages, with 256 fine illustrations, many of which are original, and 2 chromo-lithographic plates. Prices: Cloth, $4.00 net; Sheep or Half-Morocco, $5.00 net. The object of this work is to present to the student, and to the practitioner who is beginning work in the fields of ophthalmology, a plain description of the optical defects and diseases of the eye. To this end special attention has been paid to the clinical side of the question; and the method of examination, the symptomatology leading to a diagnosis, and the treatment of the various ocular defects have been brought into prominence. SECOND EDITION, REVISED AND GREATLY ENLARGED. The entire book has been thoroughly revised. In addition to this general revision, special paragraphs on the following new matter have been introduced: Filamentous Keratitis, Blood-staining of the Cornea, Essential Phthisis Bulbi, Foreign Bodies in the Lens, Circinate Retinitis, Symmetrical Changes at the Macula Lutea in Infancy, Hyaline Bodies in the Papilla, Monocular Diplopia, Subconjunctival Injections of Germicides, Infiltration-Ansesthesia, and Steriliza- tion of Collyria. Brief mention of Ophthalmia Nodosa, Electric Ophthalmia, and Angioid Streaks in the Retina also finds place. An Appendix has been added, containing a full description of the method of determining the corneal astigmatism with the ophthalmometer of Javal and Schiotz, and the rotations of the eyes with the tropometer of Stevens. The chapter on Operations has been enlarged and rewritten. “ A clearly written, comprehensive manual. . . . One which we can commend to students as a reliable text-book, written with an evident knowledge of the wants of those enteringupon the study of this special branch of medical science.”—British Medical Journal. “ The work is characterized by a lucidity of expression which leaves the reader in no doubt as to the meaning of the language employed. ... We know of no work in which these diseases are dealt with more satisfactorily, and indications for treatment more clearly given, and in harmony with the practice of the most advanced ophthalmologists.”—Mari- time Medical News. “ It is hardly too much to say that for the student and practitioner beginning the study of Ophthalmology, it is the best single volume at present published.”—Medical News. “ The latest and one of the best books on Ophthalmology. The book is thoroughly up to date, and is certainly a work which not only commends itself to the student, but is a ready reference for the busy practitioner.”—International Medical Review. PROFESSIONAL OPINIONS. “ A work that will meet the requirements not only of the specialist, but of the general practitioner in a rare degree. I am satisfied that unusual success awaits it.” William Pepper, M. D. Provost and Professor of Theory and Practice of Medicine and Clinical Medicine in the University of Pennsylvania. “ Contains in concise and reliable form the accepted views of Ophthalmic Science.” William Thomson, M. D., Professor of Ophthalmology, Jefferson Medical College, Philadelphia, Pa. CATALOGUE OF MEDICAL WORDS. 15 16 IV. B. SAUNDERS' TEXT-BOOK UPON THE PATHOGENIC BACTERIA. Spe- cially written for Students of Medicine. By Joseph McFarland, M. D., Professor of Pathology and Bacteriology in the Medico-Chirurgical College of Philadelphia, etc. 359 pages, finely illustrated. Price, Cloth, $2.50 net. The book presents a concise account of the technical procedures necessary in the study of Bacteriology. It describes the life-history of pathogenic bacteria, and the pathological lesions following invasion. The work is intended to be a text-book for the medical student and for the practitioner who has had no recent laboratory training in this department of medi- cal science. The instructions given as to needed apparatus, cultures, stainings, microscopic examinations, etc., are ample for the student’s needs, and will afford to the physician much information that will interest and profit him relative to a subject which modern science shows to go far in explaining the etiology of many diseased conditions. The illustrations have been gathered from standard sources, and comprise the best and most complete aggregation extant. “ It is excellently adapted for the medical students and practitioners for whom it is avowedly written. . . . The descriptions given are accurate and readable, and the book should prove useful to those for whom it is written.—London Lancet, Aug. 29, 1896. “ The author has succeded admirably in presenting the essential details of bacteriological technics, together with a judiciously chosen summary of our present knowledge of pathogenic bacteria. . . . The work, we think, should have a wide circulation among English-speaking students of medicine.”—N. Y. Medical Journal, April 4, 1896. “ The book will be found of considerable use by medical men who have not had a special bacteriological training, and who desire to understand this important branch of medical science.”—Edinburgh Medical ’Journal, July, 1896. LABORATORY GUIDE FOR THE BACTERIOLOGIST. By Langdon Frothingham, M. D. V., Assistant in Bacteriology and Veteri- nary Science, Sheffield Scientific School, Yale University. Illustrated. Price, Cloth, 75 cents. The technical methods involved in bacteria-culture, methods of staining, and microscopical study are fully described and arranged as simply and concisely as possible. The book is especially intended for use in laboratory work “ It is a convenient and useful little work, and will more than repay the outlay necessary for its purchase in the saving of time which would otherwise be consumed in looking up the various points of technique so clearly and concisely laid down in its pages.”—American Med.- Surg. Bulletin. FEEDING IN EARLY INFANCY. By Arthur V. Meigs, M. D. Bound in limp cloth, flush edges. Price, 25 cents net. Synopsis : Analyses of Milk—Importance of the Subject of Feeding in Early Infancy—Proportion of Casein and Sugar in Human Milk—Time to Begin Arti- ficial Feeding of Infants—Amount of Food to be Administered at Each Feed- ing—Intervals between Feedings—Increase in Amount of Food at Different Periods of Infant Development—Unsuitableness of Condensed Milk as a Sub- stitute for Mother’s Milk—Objections to Sterilization or “ Pasteurization ” of Milk—Advances made in the Method of Artificial Feeding of Infants. CATALOGUE OF MEDICAL WORKS. 17 ESSENTIALS OF ANATOMY AND MANUAL OF PRACTI- CAL DISSECTION, containing “ Hints on Dissection.” By Charles B. Nancrede, M. D., Professor of Surgery and Clinical Surgery in the University of Michigan, Ann Arbor; Corresponding Member of the Royal Academy of Medicine, Rome, Italy; late Surgeon Jefferson Medical Col- lege, etc. Fourth and revised edition. Post 8vo, over 500 pages, with handsome full page lithographic plates in colors, and over 200 illustrations. Price : Extra Cloth or Oilcloth for the dissection-room, $2.00 net. Neither pains nor expense has been spared to make this work the most ex- haustive yet concise Student’s Manual of Anatomy and Dissection ever pub- lished, either in America or in Europe. The colored plates are designed to aid the student in dissecting the muscles, arteries, veins, and nerves. The wood-cuts have all been specially drawn and engraved, and an Appendix added containing 60 illustrations representing the structure of the entire human skeleton, the whole being based on the eleventh edition of Gray’s Anatomy. “ The plates are of more than ordinary excellence, and are of especial value to students in their work in the dissecting-room.”—Journal of American Medical Association. “Should be in the hands of every medical student.”—Cleveland Medical Gazette. “ A concise and judicious work.”—Buffalo Medical and Surgical Journal. A MANUAL OF PRACTICE OF MEDICINE. By A. A. Stevens, A. M., M. D., Instructor of Physical Diagnosis in the University of Penn- sylvania, and Demonstrator of Pathology in the Woman’s Medical College of Philadelphia. Specially intended for students preparing for graduation and hospital examinations, and includes the following sections: General Diseases, Diseases of the Digestive Organs, Diseases of the Respiratory System, Diseases of the Circulatory System, Diseases of the Nervous Sys- tem, Diseases of the Blood, Diseases of the Kidneys, and Diseases of the Skin. Each section is prefaced by a chapter on General Symptomatology. Post 8vo, 512 pages. Numerous illustrations and selected formulae. Price, $2.50. FOURTH EDITION, REVISED AND ENLARGED. Contributions to the science of medicine have poured in so rapidly during the last quarter of a century that it is well-nigh impossible for the student, with the limited time at his disposal, to master elaborate treatises or to cull from them that knowledge which is absolutely essential. From an extended experience in teaching, the author has been enabled, by classification, to group allied symp- toms, and by the judicious elimination of theories and redundant explanations to bring within a comparatively small compass a complete outline of the prac- tice of medicine. 18 IV. B. SAUNDERS MANUAL OF MATERIA MEDICA AND THERAPEUTICS. By A. A. Stevens, A. M., M. D., Instructor of Physical Diagnosis in the University of Pennsylvania, and Demonstrator of Pathology in the Woman’s Medical College of Philadelphia. 445 pages. Price, Cloth, $2.25. SECOND EDITION, REVISED. This wholly new volume, which is based on the last edition of the Pharma- copoeia, comprehends the following sections: Physiological Action of Drugs; Drugs; Remedial Measures other than Drugs; Applied Therapeutics; Incom- patibility in Prescriptions; Table of Doses; Index of Drugs; and Index of Diseases; the treatment being elucidated by more than two hundred formulae. “ The author is to be congratulated upon having presented the medical student with as accurate a manual of therapeutics as it is possible to prepare.”—Therapeutic Gazette. “ Far superior to most of its class ; in fact, it is very good. Moreover, the book is reliable and accurate.”—New York Medical Journal. “The author has faithfully presented modern therapeutics in a comprehensive work, . . . and it will be found a reliable guide.”—University Medical Magazine. NOTES ON THE NEWER REMEDIES: their Therapeutic Ap- plications and Modes of Administration. By David Cerna, M. D., Ph. D., Demonstrator of and Lecturer on Experimental Therapeutics in the University of Pennsylvania. Post-octavo, 253 pages. Price, $1.25. SECOND EDITION, RE-WRITTEN AND GREATLY ENLARGED. The work takes up in alphabetical order all the newer remedies, giving their physical properties, solubility, therapeutic applications, administration, and chemical formula. It thus forms a very valuable addition to the various works on therapeutics now in existence. Chemists are so multiplying compounds, that, if each compound is to be thor- oughly studied, investigations must be carried far enough to determine the prac- tical importance of the new agents. “ Especially valuable because of its completeness, its accuracy, its systematic consider- ation of the properties and therapy of many remedies of which doctors generally know but little, expressed in a brief yet terse manner.”—Chicago Clinical Review. TEMPERATURE CHART. Prepared by D. T. Laine, M. D. Size 8x 13 inches. Price, per pad of 25 charts, 50 cents. A conveniently arranged chart for recording Temperature, with columns for daily amounts of Urinary and Fecal Excretions, Food, Remarks, etc. On the back of each chart is given in full the method of Brand in the treatment of Typhoid Fever. SAUNDERS’ POCKET MEDICAL LEXICON; or, Dictionary of Terms and Words used in Medicine and Surgery. By John M. Keating, M. D., editor of “ Cyclopaedia of Diseases of Children,” etc.; author of the “ New Pronouncing Dictionary of Medicineand Henry Hamilton, author of “ A New Translation of Virgil’s Aineid into Eng- lish Verseco-author of a “ New Pronouncing Dictionary of Medicine.” A new and revised edition. 321110, 282 pages. Prices: Cloth, 75 cents; Leather Tucks, $1.00. This new and comprehensive work of reference is the outcome of a demand for a more modern handbook of its class than those at present on the market, which, dating as they do from 1855 to I884, are of but trifling use to the student by their not containing the hundreds of new words now used in current litera- ture, especially those relating to Electricity and Bacteriology. CATALOGUE OF MEDICAL WOEKS. 19 “ Remarkably accurate in terminology, accentuation, and definition.”—-Journal of Amer- ican Medical Association. “ Brief, yet complete .... it contains the very latest nomenclature in even the newest departments of medicine.”—New York Medical Record. SAUNDERS’ POCKET MEDICAL FORMULARY. By William M. Powell, M. D., Attending Physician to the Mercer House for Invalid Women at Atlantic City. Containing 1750 Formulae, selected from several hundred of the best-known authorities. Forming a handsome and con- venient pocket companion of nearly 300 printed pages, with blank leaves for Additions; with an Appendix containing Posological Table, Formulae and Doses for Hypodermatic Medication, Poisons and their Antidotes, Diameters of the Pemale Pelvis and Foetal Head, Obstetrical Table, Diet List for Various Diseases, Materials and Drugs used in Antiseptic Surgery, Treatment of Asphyxia from Drowning, Surgical Remembrancer, Tables of Incompatibles, Eruptive Fevers, Weights and Measures, etc. Third edition, revised and greatly enlarged. Handsomely bound in morocco, with side index, wallet, and flap. Price, $1.75 net. A concise, clear, and correct record of the many hundreds of famous formulae which are found scattered through the works of the most eminent physicians and surgeons of the world. The work is helpful to the student and practitioner alike, as through it they become acquainted with numerous formulae which are not found in text-books, but have been collected from among the rising genera- tion of the profession, college professors, and hospital physicians and surgeons. “ This little book, that can be conveniently carried in the pocket, contains an immense amount of material. It is very useful, and as the name of the author of each prescription is given is unusually reliable.”—New York Medical Record. “ Designed to be of immense help to the general practitioner in the exercise of his daily calling.”—Boston Medical and Surgical Journal. 20 IV. B. SAUNDERS DISEASES OF WOMEN. By Henry J. Garrigues, A. M., M.D., Professor of Obstetrics in the New York Post-Graduate Medical School and Hospital; Gynecologist to St. Mark’s Hospital and to the German Dispensary, etc., New York City. In one very handsome octavo volume of about 700 pages, illustrated by numerous wood-cuts and colored plates. Prices : Cloth, $4.00 net; Sheep, $5.00 net. A practical work on gynecology for the use of students and practitioners, written in a terse and concise manner. The importance of a thorough know- ledge of the anatomy of the female pelvic organs has been fully recognized by the author, and considerable space has been devoted to the subject. The chap- ters on Operations and on Treatment are thoroughly modern, and are based upon the large hospital and private practice of the author. The text is eluci- dated by a large number of illustrations and colored plates, many of them being original, and forming a complete atlas for studying embryology and the anatomy of the female genitalia, besides exemplifying, whenever needed, morbid condi- tions, instruments, apparatus, and operations. EXCERPT OF COXTENTS. Development of the Female Genitals.—Anatomy of the Female Pelvic Organs.—Phys- iology.—Puberty.—Menstruation and Ovulation.—Copulation.—Fecundation.—The Climac- teric.—Etiology in General.—Examinations in General.—Treatment in General—Abnormal Menstruation and Metrorrhagia.—Leucorrhea.—Diseases of the Vulva.—Diseases of the Perineum.—Diseases of the Vagina.—Diseases of the Uterus.—Diseases of the Fallopian Tubes.—Diseases of the Ovaries.—Diseases of the Pelvis.—Sterility. The reception accorded to this work has been most flattering. In the short period which has elapsed since its issue it has been adopted and recommended as a text-book by more than 60 of the Medical Schools and Universities of the United States and Canada. “One of the best text-books for students and practitioners which has been published in the English language; it is condensed, clear, and comprehensive. The profound learning and great clinical experience of the distinguished author find expression in this book in a most attractive and instructive form. Young practitioners, to whom experienced consultants may not be available, will find in this book invaluable counsel and help.” Thad. A. Reamy, M. D., LL.D., Professor of Clinical Gynecology, Medical College of Ohio ; Gynecologist to the Good Samaritan and Cincinnati Hospitals. A SYLLABUS OF GYNECOLOGY, arranged in conformity with “An American Text-Book of Gynecology.” By J. W. Long, M.D., Professor of Diseases of Women and Children, Medical College of Vir- ginia, etc. Price, Cloth (interleaved), $1.00 net. Based upon the teaching and methods laid down in the larger work, this will not only be useful as a supplementary volume, but to those who do not already possess the text-book it will also have an independent value as an aid to the practitioner in gynecological work, and to the student as a guide in the lecture- room, as the subject is presented in a manner at once systematic, clear, succinct, and practical. CATALOGUE OF MEDICAL WORKS. 21 A MANUAL OF PHYSIOLOGY, with Practical Exercises. For Students and Practitioners. By G. N. Stewart, M. A., M. D., D. Sc., lately Examiner in Physiology, University of Aberdeen, and of the New Museums, Cambridge University; Professor of Physiology in the Western Reserve University, Cleveland, Ohio. Handsome octavo volume of 800 pages, with 278 illustrations in the text, and 5 colored plates. Price, Cloth, $3.50 net. “ It will make its way by sheer force of merit, and amply deserves to do so. It is one of the very best English text-books on the subject.”—London Lancet. “ Of the many text-books of physiology published, we do not know of one that so nearly comes up to the ideal as does Professor Stewart’s volume.”—British Medical Journal. ESSENTIALS OF PHYSICAL DIAGNOSIS OF THE THORAX. By Arthur M. Corwin, A. M., M. D., Demonstrator of Physical Diagno- sis in the Rush Medical College, Chicago; Attending Physician to the Central Free Dispensary, Department of Rhinology, Laryngology, and Diseases of the Chest. 200 pages. Illustrated. Cloth, flexible covers. Price, $1.25 net. SYLLABUS OF OBSTETRICAL LECTURES in the Medical Department, University of Pennsylvania. By Richard C. Norris, A. M., M. D., Lecturer on Clinical and Operative Obstetrics, University of Pennsylvania. Third edition, thoroughly revised and enlarged. Crown 8vo. Price, Cloth, interleaved for notes, $2.00 net. “ This work is so far superior to others on the same subject that we take pleasure in call- ing attention briefly to its excellent features. It covers the subject thoroughly, and will prove invaluable both to the student and the practitioner. The author has introduced a number of valuable hints which would only occur to one who was himself an experienced teacher of obstetrics. The subject-matter is clear, forcible, and modern. We are especially pleased with the portion devoted to the practical duties of the accoucheur, care of the child, etc. The paragraphs on antiseptics are admirable; there is no doubtful tone in the direc- tions given. No details are regarded as unimportant; no minor matters omitted. We ven- ture to say that even the old practitioner will find useful hints in this direction which he can- not afford to despise.”—New York Medical Record. A SYLLABUS OF LECTURES ON THE PRACTICE OF SUR- GERY, arranged in conformity with “ An American Text-Book of Surgery.” By N. Senn, M. D., Ph. D., Professor of Surgery in Rush Medical College, Chicago, and in the Chicago Polyclinic. Price, $2.00. This, the latest work of its eminent author, himself one of the contributors to “ An American Text-Book of Surgery,” will prove of exceptional value to the advanced student who has adopted that work as his text-book. It is not only the syllabus of an unrivalled course of surgical practice, but it is also an epitome of or supplement to the larger work. . “ 1 he author has evidently spared no pains in making his Syllabus thoroughly sive, and has added new matter and alluded to the most recent authors and operations, references are also given to all requisite details of surgical anatomy and pathology.”—B: Medical Journal, London. 22 W. B SAUNDERS' AN OPERATION BLANK, with Lists of Instruments, etc. re- quired in Various Operations. Prepared by W. W. Keen, M. D., LL.D., Professor of Principles of Surgery in the Jefferson Medical Col- lege, Philadelphia. Price per Pad, containing Blanks for fifty operations, 50 cents net. SECOND EDITION, REVISED FORM. A convenient blank, suitable for all operations, giving complete instructions regarding necessary preparation of patient, etc., with a full list of dressings and medicines to be employed. On the back of each blank is a list of instruments used—viz. general instru- ments, etc., required for all operations; and special instruments for surgery of the brain and spine, mouth and throat, abdomen, rectum, male and female genito-urinary organs, the bones, etc. The whole forming a neat pad, arranged for hanging on the wall of a sur- geon’s office or in the hospital operating-room. “Will serve a useful purpose for the surgeon in reminding him of the details of prepa- ration for the patient and the room as well as for the instruments, dressings, and antiseptics needed ”—Neiv York Medical Record " Covers about all that can be needed in any operation.”—American Lancet. “ The plan is a capital one."—Boston Medical and Surgical Journal. LABORATORY EXERCISES IN BOTANY. By Edson S. Bastin, M. A., Professor of Materia Medica and Botany in the Philadelphia Col- lege of Pharmacy. Octavo volume of 536 pages, 87 full-page plates. Price, Cloth, $2.50. This work is intended for the beginner and the advanced student, and it fully covers the structure of flowering plants, roots, ordinary stems, rhizomes, tubers, bulbs, leaves, flowers, fruits, and seeds. Particular attention is given to the gross and microscopical structure of plants, and to those used in medicine. Illustra- tions have freely been used to elucidate the text, and a complete index to facil- itate reference has been added. “ There is no work like it in the pharmaceutical or botanical literature of this country, and we predict for it a wide circulation.”—American Journal of Pharmacy. DIET IN SICKNESS AND IN HEALTH. By Mrs. Ernest Hart, formerly Student of the Faculty of Medicine of Paris and of the London School of Medicine for Women; with an Introduction by Sir Henry Thompson, F. R. C. S., M. D., London. 220 pages; illustrated. Price, Cloth, $1.50. Useful to those who have to nurse, feed, and prescribe for the sick. In each case the accepted causation of the disease and the reasons for the special diet prescribed are briefly described. Medical men will find the dietaries and recipes practically useful, and likely to save them trouble in directing the dietetic treatment of patients. CATALOGUE OF MEDICAL WORKS. 23 HOW TO EXAMINE FOR LIFE INSURANCE. By John M. Keating, M. D., Fellow of the College of Physicians and Surgeons of Philadelphia; Vice-President of the American Paediatric Society; Ex- President of the Association of Life Insurance Medical Directors. Royal 8vo, 211 pages, with two large half-tone illustrations, and a plate prepared by Dr. McClellan from special dissections; also, numerous cuts to elucidate the text. Second edition. Price, Cloth, $2.00 net. Part I., carefully prepared from the best works on Physical Diagnosis, gives a succinct account of the methods used in making examinations, and a description of the normal condition and of the earliest evidences of disease. Part II. contains the Instructions of twenty-four Life-Insurance Companies to their medical examiners. “ This is by far the most useful book which has yet appeared on insurance examination, a subject of growing interest and importance. Not the least valuable portion of the volume is Part II., which consists of instructions issued to their examining physicians by twenty-four representative companies of this country. As the proofs of these instructions were corrected by the directors of the companies, they form the latest instructions obtainable. If for these alone, the book should be at the right hand of every physician interested in this special branch of medical science/’—The Medical News, Philadelphia. NURSING: ITS PRINCIPLES AND PRACTICE. By Isabel Adams Hampton, Graduate of the New York Training School for Nurses attached to Bellevue Hospital; Superintendent of Nurses and Principal of the Training School for Nurses, Johns Hopkins Hospital, Baltimore, Md.; late Superintendent of Nurses, Illinois Training School for Nurses, Chicago, Ill. In one very handsome I2mo volume of 484 pages, profusely illustrated. Price, Cloth, $2.00 net. This original work on the important subject of nursing is at once comprehensive and systematic. It is written in a clear, accurate, and readable style, suitable alike to the student and the lay reader. Such a work has long been a desidera- tum with those entrusted with the management of hospitals and the instruction of nurses in training-schools. It is also of especial value to the graduated nurse who desires to acquire a practical working knowledge of the care of the sick and the hygiene of the sick-room. OBSTETRIC ACCIDENTS, EMERGENCIES, AND OPERA- TIONS. By L. Ch. Boisliniere, M. D., late Emeritus Professor of Obstetrics in the St. Louis Medical College. 381 pages, handsomely illus- trated. Price, $2.00 net. “ For the use of the practitioner who, when away from home, has not the opportunity of consulting a library or of calling a friend in consultation. He then, being thrown upon his own resources, will find this book of benefit in guiding and assisting him in emergencies.” 24 IF. B. SAUNDERS' THE CARE OF THE BABY. By J. P. Crozer Griffith, M. D., Clinical Professor of Diseases of Children, University of Pennsylvania; Physician to the Children’s Hospital, Philadelphia, etc. 392 pages, with 67 illustrations in the text, and 5 plates. I2mo. Price, $1.50. A reliable guide not only for mothers, but also for medical students and practitioners whose opportunities for observing children have been limited. “ The whole book is characterized by rare good sense, and is evidently written by a mas- ter hand. It can be read with benefit not only by mothers, but by medical students and by any practitioners who have not had large opportunities for observing children.”—American Journal of Obstetrics. THE NURSE’S DICTIONARY of Medical Terms and Nursing Treatment, containing Definitions of the Principal Medical and Nursing Terms, Abbreviations, and Physiological Names, and Descriptions of the Instruments, Drugs, Diseases, Accidents, Treatments, Operations, Foods, Appliances, etc. encountered in the ward or in the sick-room. Compiled for the use of nurses. By Honnor Morten, author of “ How to Become a Nurse,” “Sketches of Hospital Life,” etc. i6mo, 140 pages. Price, Cloth, $1.00. This little volume is intended for use merely as a small reference-book which can be consulted at the bedside or in the ward. It gives sufficient explanation to the nurse to enable her to comprehend a case until she has leisure to look up larger and fuller works on the subject. DIET LISTS AND SICK-ROOM DIETARY. By Jerome B. Thomas, M. D., Visiting Physician to the Home for Friendless Women and Children and to the Newsboys’ Home; Assistant Visiting Physician to the Kings County Hospital; Assistant Bacteriologist, Brooklyn Health Department. Price, Cloth, $1.50 (Send for specimen List.) One hundred and sixty detachable (perforated) diet lists for Albuminuria, Angemia and Debility, Constipation, Diabetes, Diarrhoea, Dyspepsia, Fevers, Gout or Uric-Acid Diathesis, Obesity, and Tuberculosis. Also forty detachable sheets of Sick-Room Dietary, containing full instructions for preparation of easily-digested foods necessary for invalids. Each list is numbered only, the disease for which it is to be used in no case being mentioned, an index key being reserved for the physician’s private use. DIETS FOR INFANTS AND CHILDREN IN HEALTH AND IN DISEASE. By Louis Starr, M. D., Editor of “ An American Text-Book of the Diseases of Children.” 230 blanks (pocket-book size), perforated and neatly bound in flexible morocco. Price, $1.25 net. The first series of blanks are prepared for the first seven months of infant life; each blank indicates the ingredients, but not the quantities, of the food, the latter directions being left for the physician. After the seventh month, modifications being less necessary, the diet lists are printed in full. Formula for the preparation of diluents and foods are appended. Practical, Exhaustive, Authoritative. SAUNDERS’ NEW AID SERIES OF MANUALS FOR Students and Practitioners. Mr. Saunders is pleased to announce as now ready his NEW AID SERIES OF MANUALS for Students and Practitioners. As pub- lisher of the Standard Series of Question Compends, and through intimate relations with leading members of the medical profession, Mr. Saunders has been enabled to study progressively the essential desiderata in practical “ self- helps ” for students and physicians. This study has manifested that, while the published “ Question Compends” earn the highest appreciation of students, whom they serve in reviewing their studies preparatory to examination, there is special need of thoroughly reliable handbooks on the leading branches of Medicine and Surgery, each subject being compactly and authoritatively written, and exhaustive in detail, without the introduction of cases and foreign subject-matter which so largely expand ordinary text-books. The Saunders Aid Series will not merely be condensations from present literature, but will be ably written by well-known authors and practitioners, most of them being teachers in representative American Colleges. This new series, therefore, will form an admirable collection of advanced lectures, which will be invaluable aids to students in reading and in comprehending the contents of “recommended” works. Each Manual will further be distinguished by the beauty of the new type; by the quality of the paper and printing; by the copious use of illustrations; by the attractive binding in cloth; and by their extremely low prices. 25 SAUNDERS’ NEW AID SERIES OF MANUALS. VOLUMES PUBLISHED. PHYSIOLOGY. By Joseph Howard Raymond, A. M., M. D., Professor of Physiology and Hygiene and Lecturer on Gynecology in the Long Island College Hospital, etc. Price, $1.25 net. SURGERY, General and Operative. By John Chalmers DaCosta, M. D„ Demonstrator of Surgery, Jefferson Medical College, Philadelphia, etc. Double number. Price, $2.50 net. DOSE-BOOK AND MANUAL OF PRESCRIPTION-WRITING. By E. Q. Thornton, M. D., Demonstrator of Therapeutics, Jefferson Medical College, Philadelphia. Price, $1.25 net. MEDICAL JURISPRUDENCE. By Henry C. Chapman, M.D., Pro- fessor of Institutes of Medicine and Medical Jurisprudence in the Jeffer- son Medical College of Philadelphia, etc Price, $1.50 net. SURGICAL ASEPSIS. By Carl Beck, M.D., Surgeon to St. Mark’s Hospital and to the German Poliklinik; Instructor in Surgery, New York Post-Graduate Medical School, etc. Price, $1.25 net. MANUAL OF ANATOMY. By Irving S. Haynes, M.D., Adjunct Professor of Anatomy and Demonstrator of Anatomy, Medical Department of the New York University, etc. (Double number.) Price, $2.50 net. SYPHILIS AND THE VENEREAL DISEASES. By James Nevins Hyde, M. D., Professor of Skin and Venereal Diseases, and Frank H. Montgomery, M. D., Lecturer on Dermatology and Genito- urinary Diseases, in Rush Medical College, Chicago. (Double number.) Price, $2.50 net. PRACTICE OF MEDICINE. By George Roe Lockwood, M. D., Professor of Practice in the Woman’s Medical College of the New York Infirmary, etc. (Double number.) Price, $2.50 net. OBSTETRICS. By W. A. Newman Dorland, M.D., Asst. Demonstrator of Obstetrics, University of Pennsylvania; Chief of Gynecological Dispen- sary, Pennsylvania Hospital. (Double number.) Price, $2.50 net. VOLUMES IN PREPARATION. DISEASES OF WOMEN. By J. Bland Sutton, F. R. C. S., Assistant Surgeon to the Middlesex Hospital, and Surgeon to the Chelsea Hospital for Women, London; and Arthur E. Giles, M. D., B. Sc. Lond., F. R. C. S. Edin., Assistant Surgeon to the Chelsea Hospital for Women, London. Handsomely illustrated. NERVOUS DISEASES. By Charles W. Burr, M. D., Clinical Pro- fessor of Nervous Diseases, Medico-Chirurgical College, Philadelphia, etc. NOSE AND THROAT. By D. Braden Kyle, M. D., Chief Laryngolo- gist to St. Agnes’ Hospital, Philadelphia; Instructor in Clinical Microscopy and Assistant Demonstrator of Pathology in Jefferson Medical College. *#* There will be published in the same series, at short intervals, carefully nrenared works on various subjects, by prominent specialists. 26 SAUNDERS’ QUESTION COMPENDS. Arranged in Question and Answer Form. THE LATEST, MOST COMPLETE, and BEST ILLUSTRATED SERIES OF COMPENDS EVER ISSUED. Now the Standard Authorities in Medical Literature WITH Students and Practitioners in every City of the United States and Canada. THE REASON WHY. They are the advance guard of “ Student’s Helps ”—that do help; they are the leaders in their special line, well and authoritatively written by able men, who, as teachers in the large colleges, know exactly what is wanted by a student preparing for his examinations. The judgment exercised in the selection of authors is fully demonstrated by their professional elevation. Chosen from the ranks of Demonstrators, Quiz-masters, and Assistants, most of them have be- come Professors and Lecturers in their respective colleges. Each book is of convenient size (5x7 inches), containing on an average 250 pages, profusely illustrated, and elegantly printed in clear, readable type, on fine paper. The entire series, numbering twenty-four subjects, has been kept thoroughly revised and enlarged when necessary, many of them being in their fourth and fifth editions. TO SUM UP. Although there are numerous other Quizzes, Manuals, Aids, etc. in the mar- ket, none of them approach the “Blue Series of Question Compends;” and the claim is made for the following points of excellence: 1. Professional distinction and reputation of authors. 2. Conciseness, clearness, and soundness of treatment. 3. Size of type and quality of paper and binding. Any of these Compends will be mailed on receipt of price (see over for List). 27 SAUNDERS’ QUEST10N-C0MPEND SERIES. Price, Cloth, $1.00 per copy, except when otherwise noted. 1. ESSENTIALS OF PHYSIOLOGY. 3d edition. Illustrated. Re- vised and enlarged by H. A. Hare, M. D (Price, $1.00 net.) 2. ESSENTIALS OF SURGERY. 5th edition, with an Appendix on Antiseptic Surgery. 90 illustrations. By Edward Martin, M. D. 3. ESSENTIALS OF ANATOMY. 5th edition, with an Appendix. 180 illustrations. By Charles B. Nancrede, M. D. 4. ESSENTIALS OF MEDICAL CHEMISTRY, ORGANIC AND INORGANIC. 4th edition, revised, with an Appendix. By Law- rence Wolff, M. D. 5. ESSENTIALS OF OBSTETRICS. 3d edition, revised and en- larged. 75 illustrations. By W. Easterly Ashton, M. D. 6. ESSENTIALS OF PATHOLOGY AND MORBID ANATOMY. 6th thousand. 46 illustrations. By C. E. Armand Semple, M. D. 7. ESSENTIALS OF MATERIA MEDICA, THERAPEUTICS, AND PRESCRIPTION-WRITING. 4th edition. By Henry Morris, M. D. 8. 9. ESSENTIALS OF PRACTICE OF MEDICINE. By Henry Morris, M. D. An Appendix on Urine Examination. Illustrated. By Lawrence Wolff, M. D. 3d edition, enlarged by some 300 Es- sential Formulae, selected from eminent authorities, by Wm. M. Powell, M„ D. (Double number, price $2.00.) 10. ESSENTIALS OF GYNAECOLOGY. 3d edition, revised. With 62 illustrations. By Edwin B. Cragin, M. D. 11. ESSENTIALS OF DISEASES OF THE SKIN. 3d edition, re- vised and enlarged. 71 letter-press cuts and 15 half-tone illustrations. By Henry W. Stelwagon, M. D. (Price, $1.00 net.) 12. ESSENTIALS OF MINOR SURGERY, BANDAGING, AND VENEREAL DISEASES. 2d edition, revised and enlarged. 78 illustrations. By Edward Martin, M. D. 13. ESSENTIALS OF LEGAL MEDICINE, TOXICOLOGY, AND HYGIENE. 130 illustrations. By C. E. Armand Semple, M. D. 14. ESSENTIALS OF DISEASES OF THE EYE, NOSE, AND THROAT. 124 illustrations. 2d edition, revised. By Edward Jackson, M. D., and E. Baldwin Gleason, M. D. 15. ESSENTIALS OF DISEASES OF CHILDREN. 4th thousand. By William H. Powell, M. D. 16. ESSENTIALS OF EXAMINATION OF URINE. Colored “ Vogel Scale,” and numerous illustrations. By Lawrence Wolff, M. D. (Price, 75 cents.) 17. ESSENTIALS OF DIAGNOSIS. By S. Solis-Cohen, M. D., and A. A. Eshner, M. D. 55 illustrations, some in colors. (Price, $1.50 net.) 18. ESSENTIALS OF PRACTICE OF PHARMACY. By L. E. Sayre. 2d edition, revised. 20. ESSENTIALS OF BACTERIOLOGY. 3d edition. 82 illustra- tions. By M. V. Ball, M. D. 21. ESSENTIALS OF NERVOUS DISEASES AND INSANITY. 48 illustrations. 2d edition, revised. By John C. Shaw, M. D. 22. ESSENTIALS OF MEDICAL PHYSICS. 155 illustrations. 2d edition, revised. By Fred J. Brockway, M. D. (Price, $1.00 net.) 23. ESSENTIALS OF MEDICAL ELECTRICITY. 65 illustrations. By David D. Stewart, M. D., and Edward S. Lawrance, M. D. 24. ESSENTIALS OF DISEASES OF THE EAR. By E. B. Glea- son, M. D. 89 illustrations. CATALOGUE OF MEDICAL WORKS. 29 JUST PUBLISHED. A TEXT-BOOK OF MATERIA MEDICA, THERAPEUTICS, AND PHARMACOLOGY. By George F. Butler, Ph. G., M. D., Professor of Materia Medica and of Clinical Medicine in the College of Physicians and Surgeons, Chicago; Professor of Materia Medica and Thera- peutics, Northwestern University, Woman’s Medical School, etc. 8vo, 858 pages. Illustrated. Prices: Cloth, $4.00 net; Sheep or Half-Morocco, $5.00 net. A clear, concise, and practical text-book, adapted for permanent reference no less than for the requirements of the class-room. The arrangement is believed to be at once the most philosophical find rational, as well as that best calculated to engage the interest of those to whom the academic study of the subject is wont to offer no little perplexity. Special attention has been given to the Pharmaceutical section, which is exceptionally lucid and complete. LECTURES ON RENAL AND URINARY DISEASES. By Robert Saundby, M. D. Edin., Fellow of the Royal College of Physi- cians, London, and of the Royal Medico-Chirurgical Society; Physician to the General Hospital; Consulting Physician to the Eye Hospital and to the Hospital for Diseases of Women; Professor of Medicine in Mason College, Birmingham, etc. 8vo, 434 pages, with numerous illustrations and 4 colored plates. Price, Cloth, $2.50 net. In these Lectures, which are a re-issue in one volume of the author’s well- known works on Bright's Disease and Diabetes, there is given, within a modest compass, a review of the present state of knowledge of these important affections, with such additions and suggestions as have resulted from the author’s thirteen years’ clinical and pathological study of the subjects. The lectures have been carefully revised and much new matter added to them. There has also been added a section dealing with “ Miscellaneous Affections of the Kidney,” making the book more complete as a work of reference. ELEMENTARY BANDAGING AND SURGICAL DRESSING, with Directions concerning the Immediate Treatment of Cases of Emergency. For the use of Dressers and Nurses. By Walter Pye, F. R. C. S., late Surgeon to St. Mary’s Hospital, London. Small I2mo, with over 80 illus- trations. Cloth, flexible covers. Price, 75 cents net. This little book is chiefly a condensation of those portions of Pye’s “ Surgical Handicraft” which deal with bandaging, splinting, etc., and of those which treat of the management in the first instance of cases of emergency. Within its own limits, however, the book is complete, and it is hoped that it will prove extremely useful to students when they begin their work in the wards and casualty rooms, and useful also to surgical nurses and dressers. “ The directions are clear and the illustrations are good.”—London Lancet. “ The author writes well, the diagrams are clear, and the book itself is small and portable, although the paper and type are good.”—British Medical Journal. JUST ISSUED. ANOMALIES AND CURIOSITIES OF MEDICINE. BY GEORGE M. GOULD, M. D„ and WALTER L. PYLE, M. D. SOLD BY SUBSCRIPTION. Several years of exhaustive research have been spent by the authors in the great medical libraries of the United States and Europe in collecting the material for this work. Medical literature of all ages and all languages has been carefully searched, as a glance at the Bibliographic Index will show. The facts, which will be of extreme value to the author and lecturer, have been arranged and annotated, and full reference footnotes given, indicating whence they have been obtained. In view of the persistent and dominant interest in the anomalous and curious, a thorough and systematic collection of this kind (the first of which the authors have knowledge) must have its own peculiar sphere of usefulness. As a complete and authoritative Book of Reference it will be of value not only to members of the medical profession, but to all persons interested in general scientific, sociologic, and medico-legal topics; in fact, the general inter- est of the subject and the dearth of any complete work upon it make this volume one of the most important literary innovations of the day. An especially valuable feature of the book consists of the Indexing. Besides a complete and comprehensive General Index, containing numerous cross-references to the subjects discussed, and the names of the authors of the more important reports, there is a convenient Bibliographic Index and a Table of Contents. The plan has been adopted of printing the topical headings in bold= face type, the reader being thereby enabled to tell at a glance the subject- matter of any particular paragraph or page. Illustrations have been freely employed throughout the work, there being 165 relief cuts and 130 half-tones in the text, and 12 colored and half-tone full- page plates—a total of over 320 separate figures. The careful rendering of the text and references, the wealth of illustrations, the mechanical skill represented in the typography, the printing, and the bind- ing, combine to make this book one of the most attractive medical publications ever issued. Handsome Imperial Octavo Volume of 968 Pages. PRICES: Cloth, $6.00 net: Half Morocco. $7.00 net. 30 IN PREPARATION. AN AMERICAN TEXT=BOOK OF GENITOURINARY AND SKIN DISEASES. Edited by L. Bolton Bangs, M. D., Late Professor of Genito-Urinary and Venereal Diseases, New York Post-Graduate Medical School and Hospital, and William A. Hardaway, M. D., Professor of Diseases of the Skin, Missouri Medical College. AN AMERICAN TEXT=BOOK OF DISEASES OF THE EYE, EAR, NOSE, AND THROAT. Edited by G. E. de Schweinitz, M. D., Ophthalmology in the Jefferson Medical College, and B. Alexander Randall, M. D., Professor of Diseases of the Ear in the Universityof Pennsylvania and in the Philadelphia Polyclinic. MACDONALD’S SURGICAL DIAGNOSIS AND TREATMENT. Surgical Diagnosis and Treatment. By J. W. Macdonald, M. D., Graduate of Medicine of the University of Edinburgh; Licentiate of the Royal College of Surgeons, Edinburgh; Professor of the Practice of Surgery and of Clinical Surgery, Minneapolis College of Physicians and Surgeons. ANDERS’ THEORY AND PRACTICE OF MEDICINE. A Text=Book of the Theory and Practice of Medicine. By James M. Anders, M. D., Ph. D., LL.D., Professor of the Theory and Practice of Medicine and of Clinical Medicine, Medico-Chirurgical Col- lege, Philadelphia. SENN’S GENITOURINARY TUBERCULOSIS. Tuberculosis of the Genito= Urinary Apparatus, Male and Fe= male. By Nicholas Senn, M. D., Ph. D., LL.D., Professor of the Prac- tice of Surgery and of Clinical Surgery, Rush Medical College, Chicago. PENROSE’S GYNECOLOGY. A Text=Book of Gynecology. By Charles B. Penrose, M. D., Professor of Gynecology, University of Pennsylvania. HIRST’S OBSTETRICS. A Text=Book of Obstetrics. By Barton Cooke Hirst, M. D., Professor of Obstetrics, University of Pennsylvania. MOORE’S ORTHOPEDIC SURGERY. A Manual of Orthopedic Surgery. By James E. Moore, M. D., Professor of Orthopedics and Adjunct Professor of Clinical Surgery, Uni- versity of Minnesota, College of Medicine and Surgery. HEISLER’S EMBRYOLOGY. A Text=Book of Embryology. By John C. PIeisler, M. D., Pro- sector to the Professor of Anatomy, Medical Department of the University of Pennsylvania. 31 NOW READY, VOLUMES FOR 1896 AND 1897. AMERICAN YEAR-BOOK OF MEDICINE and SURGERY. Edited by GEORGE M. GOULD, A. M., M. D. Assisted, by Eminent American Specialists and Teachers. The knowledge gained is equal to a post-graduate course. Notwithstanding the rapid multiplication of medical and surgical works, still these publications fail to meet fully the requirements of the general physician, inasmuch as he feels the need of something more than mere text-books of well- known principles of medical science. Mr. Saunders has long been impressed with this fact, which is confirmed by the unanimity of expression from the pro- fession at large, as indicated by advices from his large corps of canvassers. This deficiency would best be met by current journalistic literature, but most practitioners have scant access to this almost unlimited source of information, and the busy practiser has but little time to search out in periodicals the many interesting cases whose study would doubtless be of inestimable value in his practice. Therefore, a work which places before the physician in convenient form an epitomization of this literature by persons competent to pronounce upon The Value of a Discovery or of a Method of Treatment cannot but command his highest appreciation. It is this critical and judicial function th'at will be assumed by the Editorial staff of the “ American Year- Book of Medicine and Surgery.” It is the special purpose of the Editor, whose experience peculiarly qualifies him for the preparation of this work, not only to review the contributions to American journals, but also the methods and discoveries reported in the leading medical journals of Europe, thus enlarging the survey and making the work characteristically international. These reviews will not simply be a series of undigested abstracts indiscriminately run together, nor will they be retrospective of “ news ” one or two years old, but the treatment presented will be synthetic and dogmatic, and will include only what is new. Moreover, through expert condensation by experienced writers these discussions will be Comprised in a Single Volume of about 1200 Pages. The work .will be replete with original and selected illustrations skilfully reproduced, for the most part in Mr. Saunders’ own studios established for the purpose, thus ensuring accuracy in delineation, affording efficient aids to a right comprehension of the text, and adding to the attractiveness of the volume. Prices: Cloth, $6.50 net; Half Morocco, #7.50 net. W. B. SAUNDERS, Publisher, 925 Walnut Street, Philadelphia. Uniform with the “American Text-Book” Series. SECOND EDITION, REVISED AND GREATLY ENLARGED Notes on the Newer Remedies THEIR THERAPEUTIC APPLICATIONS AND MODES OF ADMINISTRATION. BY DAVID CERNA, M.D., Ph. D., Demonstrator of Physiology in the Medical Department of the University of Texas ; formerly Demonstrator of and Lect- urer on Experimental Therapeutics in the University of Pennsylvania. Post 8vo. 250 J?aj»’ee. PRICE, $1.25. The work takes up in alphabetical order all the Newer Remedies, giving their physical properties —solubility—therapeutic application—administra- tion and chemical formula. It will, in this way, form a very valuable addition to the various works on Therapeutics now in ex- istence. Chemists are so multiplying compounds that if each compound is to be thoroughly studied, inves- tigations must be carried far enough to determine the practical importance of the new agents. Brevity and conciseness compel the omission of all biographical references. MANUAL OF MATERIA MEDICA AND THERAPEUTICS. BY A. A. STEVENS, A.M., M. D., Instructor of Physical Diagnosis in the University of Pennsylvania, and Demonstrator of Pathology in the Woman’s Medical College of Philadelphia. 435 Pages. PRICE, CLOTH, $2.25. This manual has been prepared especially for students, with the hope that it may serve as a thoroughly comprehensive outline of modern therapeutics. The work, which is based on the 1890 edition of the U.S. Pharmacopoeia, comprehends the following sections: Physio- logical Action of Drugs; Drugs; Remedial Measures other than Drugs; Applied Thera- peutics; Incompatibility in Prescriptions; Table of Doses; Index of Drugs; and In- dex of Diseases; the treatment being eluci- dated by more than two hundred formulae. Saunders’ New Aid Se NOW REj> DOSE-I AND M-AJSTU OF PRESCRIPTION- uiillllW. BY E. Q. THORNTON, M. D., Demonstrator of Therapeutics, Jefferson Medical College, Philadelphia. PRICE, CLOTH, $1.25 net. But little attention is generally given, in works on Materia Medica and Therapeutics, to the methods of combining remedies in the form of prescriptions, and this manual has been written especially for students, in the hope that it may serve to give a thorough and comprehensive knowledge of the sub- ject. The work, which is based upon the last (1890) edition of the Pharmacopoeia, fully covers the subjects of Weights and Measures, Prescriptions (form of writing, general direc- tions to pharmacist, grammatical construction, etc.), Dosage, Incompatibles, Poisons, etc.