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Histology 
DEPARTMENT OF ANATOMY 
COLLEGE OF PHYSICIANS AND SURGEONS 
1923 PREFACE 
The present volume includes the third series of student papers prepared 
and presented by members of the first year class in connection with the course 
in Histology and Embryology. This feature was introduced several years 
ago as an experiment intended primarily to stimulate the student’s interest 
in anatomical science by giving him some work for which he was entirely 
responsible. The enthusiastic response of the students and the high quality 
of the papers presented were very gratifying, and we feel strongly inclined 
to incorporate this work as a permanent feature of the course. Pedagogically, 
there can be no doubt as to its educational value. The student is familiarized 
with the methods of exploring the literature of a special field. He is trained 
in the proper selection and evaluation of material read, and in the organization 
of such material into a constructive and unified summary. The experience 
of the last three years has convincingly demonstrated that such work fur- 
nishes an excellent means for stimulating and sustaining the initiative and 
interest of the student. 
The class desires to thank Professor Huntington for his kind permission 
to reprint a number of his previously published illustrations. 
ADOLPH bJlWYN. 
Department of Anatomy 
Columbia University. TABLE OF CONTENTS 
Page 
1. The Nature and Function of the Pituitary Body 1 
P. E. Benson, J. H. Stickler, R. P. Shelton and 
J. W. Tourney. Jr. 
2. Mendelian Inheritance In Man 14 
Misses N. M. Lafloofy, H. M. Levin and 
Mr. J. T. Saunders 
3. The Structure, Development and Function of the Hemolymph 
Glands 25 
H. Blau and A. D. Spielman 
4. Senescence and Rejuvenescence 35 
Misses M. Janeway and E. Knox 
5. The Growth of Tissues In Vitro 41 
M. L. Anson and A. E. Mirsky 
6. Intravital Staining and Ultra-Violet Photography 48 
Y. Kneeland, Jr., and R. F. Solley 
7. The Interstitial Gland of the Testis. Its Histology and 
Significance 55 
P. Byron, F. W. Kerr, J. C. Kilroe and A. Wolf 
8. The Reactions of Living Cells to Foreign Bodies 63 
Miss J. Ruhl, Messrs. J. Brandriss and 
E. J. Henschel 
9. The Evolutionary Significance of Variations 71 
I. J. Tartakow and I. Weinstein THE NATURE AND FUNCTION OF THE PITUITARY 
BODY 
IN man the pituitary body, or hypophysis cerebri, is located slightly an- 
terior to the centre of the head. It is a gland, ovoid in general shape, 
and nearly as small as a pea. These things have been known for several 
centuries—but an idea of the nature and function of the pituitary body has been 
attained only in the past few decades. Vesalius, who lived some four hundred 
years ago, and whom Sir William Osier put down as ‘‘the real maker of 
modern anatomy,” gave the name “pituitary” because he believed the gland 
secreted pituita. which is a term from the Latin and means nasal phlegm. A 
cold in the head was due to an increased function of this organ, supposedly. 
But Vesalius was incorrect in this view ; and we now know the pituitary body 
to be essentially an endocrine or gland of internal secretion or ductless gland. 
Certain death follows its destruction; certain diseases and disfigurations fol- 
low its distortion. In 1886, Marie distinguished between acromegaly and 
gigantism—two abnormal conditions which we will include among others. 
Oliver and Schafer, nine years later, in 1895, showed that an injection of an 
extract of the pituitary body causes a rise in blood pressure. The remarkable 
influence of this small structure upon the processes of development and meta- 
bolism is now realized after these discoveries. The pituitary is very old 
phylogenetically as well as embryologically. 
As a preliminary to the nature and function, let us consider in some 
detail the anatomy of the gland in question—including the macroscopic or gross, 
and the microscopic or histological anatomy. Experiments will be cited. Then 
clinical cases of deranged pituitary will be taken up and therapeutic uses oi 
injections of its extract. 
Anatomy of the Normal Adult Human Pituitary Body 
The long axis is directed transversely and mjeasurers about a half an inch— 
while the measurement antero-posteriorly is approximately one-quarter of an 
inch. From above downward it is also about a quarter-inch. The total weight 
is normally about 0.5 gram. It is composed of two lobes—a large anterior 
lobe and a smaller posterior lobe. These are closely applied the one to the 
other, and Cushing observes that the posterior lobe fits into the anterior like 
a baseball into a catcher’s mit. The infundibulum, or stalk of the hypo- 
physis, which extends downward and somewhat anteriorly from that portion 
of the base of the brain designated the tuber cinereum, is attached to the 
posterior lobe. The midsagittal plane bisects the pituitary body and stalk 
into two more or less equal halves. Some difficulty is experienced in disect- 
ing out the gland due to its softness and the adhesion of its capsule to adjacent 
structures. It is not easy to distinguish the anterior from the posterior lobe 
superficially, except that the anterior is the darker in color usually, due to its 
greater vascularity—the color approaching a brick red. A slight furrow some- 
1 times marks off the two lobes, the one from the other. The blood supply for 
the anterior lobe is from small hypophyseal branches coming from each of the 
two internal carotid arteries as they pass immediately lateral to the hypophysis 
or pituitary body. Blood is carried to the posterior lobe via minute branches 
from the circle of Willis. Innervation is probably through twigs from the 
carotid plexus, which is sympathetic in nature, and surrounds the internal 
carotid artery. 
Briefly, the organ under discussion is lodged in that depression in the 
superior surface of the body of the sphenoid bone known as the fossa hypo- 
physeos. Bone lies in front of, below, and behind the gland, in general. This 
is referred to as the sella turcica (sometimes spelled tursica), which signifies 
an oriental or Turk’s saddle. The back of the fossa is overhung by the 
dorsum sellae which anteriorly and on either side gives rise to a prominent 
tubercle—the posterior clinoid process. Similarly tubercles project backward 
from anteriorly, partly enclosing the fossa hypophyseos superiorly. The an- 
terior wall of the fossa, from above downward is called the sulcus chiasmatis 
(for the lodgment of the optic chiasm) and the tuberculin sellae. Further 
anterior to the fossa are the superior parts of two air spaces—the sphenoidal 
sinuses—partitioned off from one another vertically, and which do not com- 
municate posteriorly. These must be opened, in approaching the hypophysis 
when operations are performed upon it via the nasal route. 
Lateral to the pituitary body are the cavernous venous sinuses—-each hav- 
ing embedded in its lateral wall the internal carotid artery with its sym- 
pathetic nerve plexus, and the following cranial nerves: (1) The oculomotor 
(III) ; (2) the trochlear (IV) ; (3) the ophthalmic and maxillary divisions 
of the trigeminal (V) ; and (4) the abducent (VI). Sometimes hypophyseal 
tumors cause pressure upon these structures, giving rise to certain signs and 
symptoms. The floor of the hypophyseal fossa is on a level with a plane 
projected backward from the nasion (the middle of the naso-frontal suture) 
to the inion (the external occipital protuberance). The distance from nasion 
to the pituitary body is from 2)4 to 2)4 inches. The roof of the fossa is a 
fibrous membrane fastened to the four posts of the sella turcica and having 
a small horizontal aperture for the passage of the infundibulum from the 
base of the brain to the posterior lobe. 
Histologically, the anterior lobe consists of solid branched epithelial cords, 
of irregular caliber, and which frequently anastomose. These cords are 
separated from one another by wide lacunar capillaries derived from the 
several arterioles. The wide terminal vessels are arteriovenous connections 
having a sinusoidal structure. Particularly in the central portion of the lobe, 
the cords are covered with eosinophilic cells of two types—large granular and 
small oxyphiles having little cytoplasm. The former type seems to stain 
darkly with Wigert’s elastic tissue stain. Both types of eosinophiles have 
round nuclei. The axial cells of the cords are neutrophilic and less granular. 
Basophile cells occur at the periphery of the anterior lobe. 
The posterior lobe consists of a mass of neuroglia cells, the pars nervosa, 
and an epithelial investment, the narrow pars intermedia. The cells of the 
latter are basophile sometimes ciliated and tend to become cyst-like, the cysts 
containing “colloid” secretion. The pars nervosa contains neuroglia and 
ependym'al cells, but no nerves and only a few nerve fibres. The ependyma 
lines the cavity which extends downward into the lobe from the infundi- 
bulum. 
2 Tilney’s division of the gland, compared with the terminology used above, 
follows: 
A. Pars Buccalis or Glandularis : • 
1. Pars distalis (anterior lobe) ' 
2. Pars juxta—neuralis (Intermediate portion ) 
(a) Pars tuberalis 
(b) Pars infundibularis. 
B. Pars Neuralis (Posterior Lobe—pars nervora above) 
(i) Eminentia saccularis 
(ii) Infundibulum 
(iii) Processus infundibuli. 
Although much work has been done on the function of the hypophysis, 
the results in many cases have been conflicting, mainly because the “active 
principles” have been never successfully isolated. Our knowledge is based 
on the results of extirpation, or of feeding dessicated gland and injection of 
glandular extracts. As the functions of the pars anterior on one hand, 
and the pars intermedia and pars nervosa on the other, appear to be quite 
different, they shall be considered separately. 
Function of Anterior Lobe. 
The pars anterior has been found to be concerned largely with the 
development of the skeleton and general growth of the body, especially the 
development of the sexual glands. 
The removal of the anterior lobe of the dog causes coma and death, 
generally within three days. However, if some of the tissue is left intact 
the dogs do not die but develop the following symptoms : 
1. Sudden cessation of growth. 
2. Disturbances in ossification. 
3. Exaggerated adiposity. 
4. Genital hypoplasia. 
Inversely Goetch found that by feeding anterior lobe to young rats there 
was a stimulation of growth, and a development of sexual glands. Increase 
in sexual activity has been noted as an effect of anterior lobe administration 
in man, and there is a hyperplasia of the anterior lobe in women during 
pregnancy. 
Much of our knowledge of the function of the anterior lobe especially 
has been derived from the observation of cases having over secretion of the 
anterior lobe autacoid, hyperpituitarism; or having an insufficiency of secre- 
tion, hypopituitarism. 
Over secretion of the anterior lobe early in life causes in the boy 
sexual precocity, and in the girl precocious masculinity, as made evident by 
hypertrichosis and deep voice. But the most apparent differences in func- 
tional activity are the disturbances in ossification. When the onset of hyper 
hypophysism occurs before the epiphyses have joined a remarkable growth 
of the skeleton follows and gigantism is the result. 
If the disease commences later in life when the epiphyses have fused, 
gigantism does not occur, but there are changes in the bones of the head, 
face, hands, feet and thorax, acromegaly, which will be described later. Blair 
Bell believes that true gigantism cannot be considered pathological in the 
absence of acromegaly, for the giants produced are hypermetric, but no one 
Function 
3 part is abnormally developed. It may, in fact, be due merely to adolescent 
hyperhypophysism just as one sees hyperthyroidism in girls at puberity, a 
condition which produces a temporary effect that subsequently subsides. Mason 
says that the difference between gigantism and acromegaly is explained per- 
haps by a different evolution of the cellular hyperplasia of the anterior lobe. 
When proliferation follows the normal, gigantism appears; when it is 
atypical acromegaly results. In other words, gigantism is due to hyper- 
pituitarism, and acromegaly to dyspituitarism. 
Concerning the results of underfunctioning of the anterior lobe, less is 
definitely known. To this hypopituitarism of the anterior lobe has been 
ascribed the dystrophy adiposogenitalis syndrome (to be described later), 
which is characterized by a tremendous increase in fat, and retardation of 
sexual development. However, Cushing believes this to be due to the under 
secretion of the posterior lobe. Blair Bell believes dystrophy adiposogenitalis 
to be caused by a general hypopituitarism for both lobes, for whole gland 
extracts are the best medicinal treatment for relief, and the excessive carbo- 
hydrate tolerance in these cases is due to under secretion of the posterior lobe. 
It is not known whether or not hypopituitarism is a congenital lesion, 
for it is not until the child is growing up that signs of this lesion become 
recognizable. 
Hypopituitarism before puberty gives rise to three conditions: 
1. Infantilism (somatic and sexual) without adiposity. 
2. Stunted growth with sexual infantilism and adiposity. 
3. Overgrowth with some adiposity and genital inactivity. 
The first case, Cushing believes is due to insufficiency of pars anterior 
alone, but 2 and 3 may be due to general hypopituitarism of the whole gland. 
A chemical unit of unknown composition, was isolated by Robertson in 
1916, known as tethelin, the use of which is said to be equivalent in all ways 
to the administration of the whole anterior lobe, and should be of clinical 
value. However there is no proof that this is the “active principle” of the 
anterior lobe. When tethelin is decomposed by mild hydrolysis, inosite is 
found among the products of the reaction. This is interesting from the 
fact that it is a constituent of rapidly growing parts of plants. Tethelin 
stimulates growth in young animals just as anterior lobe extract, and is 
believed to have a hastening action in the healing of wounds. 
There has been no experimental evidence showing physiological activity 
in the pars tuberalis. 
Function of Posterior Lobe. 
The pars intermedia will be considered with the pars nervosa because 
there has been much evidence to show that the secretion of the former gathers 
in the latter. It has been theoretically advanced that the epithelium of the 
pars intermedia secretes a thin colloid which finds its way to the pars nervosa 
and is there stored as a hyaline material. 
The function of the posterior lobe (including pars intermedia and pars 
nervosa) as observed by the administration of posterior lobe extract is as 
follows: 
1. Pressor action. Oliver and Schafer discovered that posterior lobe 
extract increases blood pressure with a small decrease in heart rate and 
strengthening of the systole. Its action is less intense but lasts longer than 
that caused by epinephrin. The secretion of the pars intermedia is thought 
4 to have a depressor action for a depressor substance has been isolated in this 
part. Bell believes that this depressor substance is changed to pressor as it 
goes back to the posterior lobe. At any rate the resultant action of the 
secretion of the posterior lobe is pressor. The active principles of the pos- 
terior lobe are present at an early age; and pressor responses are made from 
foetal hypophyseal extracts, 
2. Stimulation of contraction in smooth muscle. Certainly the most 
important therapeutic use of posterior lobe extract is its constrictor action 
on uterine masculature. It also causes an increase in milk flow of the mam- 
mary gland. This is not a true galactogogue effect, because the increased 
flow of milk stops as soon as the supply of milk present in the lumens of the 
glandular alveoli is forced out by contraction of the smooth muscle fibres 
about the alveoli, which is caused by the action of the posterior lobe extract. 
It also stimulates peristalsis. This was ascertained by Zondek in 1920, who 
by fitting a celluloid window in the abdomen of dogs observed the intestine 
directly. 
3. Carbohydrate metabolism. The posterior lobe secretes an autacoid 
which lowers the tolerance for sugar, and the injection of this extract will 
lower sugar tolerance until glucosuria becomes established. Glycosuria often 
follows an operation in which the posterior lobe has been stimulated by man- 
ipulation. If the posterior lobe is removed, however, there will be an in- 
creased sugar tolerance to the extent that diabetes will not result even after 
the removal of the pancreas. It has been suggested that this increased tol- 
erance for sugar is the cause of exaggerated adiposity in cases of hypopitui- 
tarism, which must involve the posterior lobe. Polyuria is generally asso- 
ciated in these cases with glycosuria and may be caused by the elect of 
posterior gland extract upon the convoluted tubules of the kidney themselves. 
In regard to carbohydrate tolerance Cushing says, “In our canine experiments 
it was noted that a transient spontaneous glycosuria was often the immediate 
sequel of certain operative manipulations involving the posterior lobe, but 
contrary to our expectations further study showed that instead of a persistent 
lowering of the assimilation limit for sugars the tolerance ultimately rose 
and remained far above normal. This was shown moreover, to be a con- 
sequence of posterior rather than of anterior lobe deficiency. 
“It was subsequently observed that patients suffering from unmistakable 
hypophyseal deficiency associated with destructive pathological processes simi- 
larly showed a high, often an extraordinary tolerance for sugars—these usually 
being patients who had acquired or who were acquiring adiposity. Further, 
a majority of the individuals who exhibited evidences of overgrowth from 
hyperpituitarism (acromegaly and gigantism) were found to possess not a 
lowered but a high tolerance—an indication of the fact that at least so 
far as the posterior lobe was concerned they were passing from a state of 
increased glandular activity to one of lowered activity. 
“The matter was further tested both in the laboratory and clinic, by 
atoning for the functional deficiency through the administration of glandular 
extracts. It was found as Borchard had previously observed, that the in- 
travenous injection of posterior lobe extract in normal animals could produce 
glycosuria, and, what was more to the point, that the assimilation limit, which 
had been greatly raised in consequence of the removal or obstruction of the 
posterior lobe, could be again lowered to a normal, or even to a subnormal, 
level by injections or oral administration of extracts (those of the posterior 
5 lobe proving far more efficient in this respect than those of the pars anterior, 
of thyroid or of adrenal).” 
Other effects of posterior lobe administration have been noticed, not of 
such great importance, and about which less is known. In regard to further 
influence on kidneys, an intravenous injection of posterior lobe extract is said 
to be a diuretic; while an intramuscular or subcutaneous injection is said to 
be a depressor and an antidiuretic. An effect on respiration has been re- 
corded, possibly due to a constriction of bronchial musclature. Also the 
secretions of the liver, pancreas, and salivary glands are said to be inhibited 
by posterior lobe extract. 
The attempts at isolating in a pure indentifiable condition the active prin- 
ciples of the posterior lobe have been unsuccessful. It was formerly believed 
that histamin (beta imidazolylethylamin) was the plain muscle stimulating 
constituent of the pituitary gland, but it is questionable if this is present 
in the perfectly fresh gland. 
In 1914 Fiihner was able to obtain a large series of crystalline compounds 
by precipitation of the protein free extracts of the material with phosphotung- 
stic acid, and then treating this mixture to get sulfate salts. The mixture 
he named hypophysin ’ and considered it to contain between four and eight 
active principles of the posterior lobe. 
In addition there are many posterior lobe extracts on the market, com- 
monly known as “infundibulin,” although this name is quite misleading. Blair 
Bell suggests the use of infundibulin in shock for maintenance of blood 
pressure; also in collapse, sepsis, serum sickness, menopausal flushings, and 
asthenia. Its greatest therapeutic use is in the acceleration of labor, and it 
is also valuable in the prevention of post partum hemmorhage by contracting the 
uterus. It has been used in Cesarean section (a few drops applied directly 
to the uterus for a bloodless field). Infundibulin has been used in paresis of 
the bladder; and with more doubtful results to prevent paralytic distension 
of the stomach and intestine after abdominal operations. Injection of pos- 
terior lobe solution diminishes thirst, volume of urine, and increases the 
specific gravity of the urine in cases of diabetes insipidus. Local application 
is effective against capillary hemorrhage, next in value to epinephrin. Oral 
administration in all cases is practically ineffective, for posterior lobe extract, 
although not acted upon by pepsin, is destroyed by trypsin. 
There is a synergy of the pituitary gland and the other endocrines. There 
is hypertrophy after thyriodectomy, after castration, or removal of the 
adrenals. 
Experiments On Amphibia 
Some valuable work has been done on the effect of extirpating the hypo- 
physis of Anurans at a very early age, and observing the subsequent changes in 
development. Anurans were used because in these forms it is possible to 
ablate the epithelial anlage of the hypophysis at the time of its first appear- 
ance as an invagination of the oral ectoderm. In Allen’s experiments the 
hypophyseal anlage was removed by making a transverse frontal cut exposing 
the ventral surface of the pituitary ingrowth. This was an extremelv delicate 
operation for the Anuran larvae were but from 3.5 to 4 mm. in length, and 
the medullary folds were just closing. Rana pipens, the common frog, was 
used in these experiments. Very clean cut experimental results were obtained 
because of the great number of individuals used, the rapidity of development, 
and the ease of regulating controls and environmental conditions. The anlage 
6 from the buccal ectoderm gives rise to the pars anterior, pars intermedia; and 
pars tuberalis. In all cases the pars nervosa was not removed, and the 
Anurans in which the hypophyseal anlage has been extirpated, but which still 
contain the pars posterior, shall be referred to for convenience as ‘'pituitary- 
less” tadpoles. 
I. Removal of Anterior Lobe Anlage. 
Allen’s results of extirpating the anterior lobe. anlage were as follows: 
1. Retardation of Growth. Size very small in comparison with controls. 
Limb buds extremely slow in development. 
2. Failure to metamorphose. 
3. “Silvering”; that is, the epithelium changed from its normal dark 
color to a creamy silver color. 
4. Extremely high mortality. Of 30 individuals rendered pituitaryless, 4 
remained alive in 33 days. In another set, of 100 individuals rendered pitui- 
taryless, 7 remained alive in 32 days. It is probable that when the operation 
removed the entire anlage, death invariably resulted. Smith had similar 
results in independent experiments. 
II. Transplantation of Adult hypophysis to young Rana pipens larvae. 
The following experiments by Allen were based in their results on 384 
operations. The tissue ingrafted was from adult frogs and contained all 
parts of the pituitary gland but the pars tuberalis. The ingrafted tissue was 
placed in a pocket under the skin below the right eye. When this tissue was 
transplanted to pituitaryless tadpoles they became larger than the controls, and 
there was acceleration in the development of the hind leg buds. 
The intermediate lobe alone was implanted in pituitaryless tadpoles, with 
the result that their abnormal silvery color was changed again back to the 
normal dark color. 
The intermediate and posterior lobe was implanted in pituitaryless tad- 
poles, with the result that the silvery color changed back to dark, and there 
was a general contraction of the body walls which gradually disappeared. 
The posterior lobe alone was implanted in pituitaryless tadpoles with the 
result that they remained silvery in color, and there was a general contraction 
of the body walls which gradually disappeared. 
These results may be summarized as follows: 
1. The anterior lobe of the hypophysis stimulates growth and meta- 
morphosis. 
2. The intermediate lobe is very largely concerned in regulating such 
color changes as are controlled by the hypophysis. 
3. The posterior lobe causes marked contraction of the body walls. 
The effects of 1 and 3 are most interesting because of their great simi- 
larity to what we know about the function of the anterior and of the posterior 
lobe of the human pituitary gland. 
The effect of 2, as far as we know has no exact counterpart in the func- 
tion of the human pituitary gland, thought it may be said that increase in 
pigmentation is often present in cases of acromegaly. 
In regard to silvering in the tadpole, Swingle says, “It remained for 
Atwell (T9) to show that it is the lack of the pars intermedia that is 
responsible for the albino appearance of hypophysectomized larvae. He ex- 
tirpated the hypophysis of the frog embryo and, following the silvering of 
7 the tadpoles places them in a dilute extract of pars intermedia of beef pitui- 
tary. The animals soon underwent a striking color change from silvery to 
dark, in the latter condition closely resembling normal tadpoles.” The silver- 
ing is brought about, according to Swingle, by changes in the pigment bodies 
of the epithelium. Extirpation of the anterior lobe causes the more super- 
ficial pigment bodies, which contain guanine and xanthine, to spread out and 
ramify in an arborescent manner, thus giving the creamy silver effect so 
marked in hypophysectomized tadpoles. In addition extirpation of the an- 
terior lobe causes the deeper pigment bodies, the melanophores which are black, 
to shrivel up and become more condensed. Inversly, implantation of the pars 
intermedia in hypophysectomized tadpoles, causes contraction of the zantho- 
leucophores, which contain the superficial, light colored pigment. 
Diseases 
The results of diseases of the ductless glands in general may be shown in: 
(1) Disturbances of the gland in question. 
(2) Secondary disturbances in other glands (because all the endocrines 
are bound together, as it were), causing a polyglangular syndrome 
(syndrome = sum total of symptoms). 
(3) Involvement of the vegetative nervous system, and therefore the 
influence on many organs. 
Pituitary syndromes are characterized by: 
A. Dystrophic Conditions 
(1) Acromegalia (acromegaly) 
(2) Gigantism 
(3) Pituitary Infantilism. 
B. General Disorders of Nutrition 
(1) Dystrophy Adiposogenitalis 
(2) Pituitary Diabetes. 
A-1 Acromegalia, also spelled acromegaly, according to Marie, is a “non- 
congenital hypertrophy of the limbs and head.” The diagnosis may be made 
on sight. 
Symptoms 
Pace—Lengthened, having the appearance of an elongated oval. 
Forehead: Low. Supraorbital ridges prominent. 
Eyes: Small. 
Nose: Enormous, the increase in size being in all directions. 
Cheek bones prominent. Cheeks sunken. 
Ears : Abnormally long. 
Lips: Especially the lower, are thick and fall down. 
Tongue: Hypertrophied. Sometimes interferes with swallowing. 
Mandible: Excessive development. Chin stuck forward. 
Head—Cranium—Little changed. Anterior-posterior diameter slightly in- 
creased. Voluminous external occipital protuberance (inion). Increased 
height and depth of frontal and maxillary sinuses. 
Upper Extremities—Arms and forearms normal. Wrists slightly hyper- 
trophied. 
Hands—characteristic deformities. Large, thick and spade-like. Both 
the bones and the soft parts are hypertrophied. Apparently padded. 
Fingers short—sausage shaped. Square at ends and as large at ends 
8 as at bases. Nails flattened. Short. Striated longitudinally and 
hardly cover dorsal surface of ungual phalynx. Lateral bony growth 
2/$ distal on first phalanges of the fingers. 
Lower Extremities—See upper extremities. Similar. Thigh and leg normal, 
Enlargement from heel to toe. Big toe larger in proportion. 
Thorax—Malformation less constant. (Cervico—dorsal kyphosis, sometimes). 
Skin—Sometimes altered—but, according to Osier, never harsh and dry 
looking as in myxedema (hypothyroidism). Often pigmented at level 
of the eyelids. 
Hair—thick. 
Articulations—Prominent and often seat of spasms. 
Genital Disturbances—In the male: frigidity and often atrophy of the 
testicles. 
In the female: menses decrease or stop. 
Viscera—Splanchnomegalia often. Heart may enlarge without apparent cause. 
Liver and spleen also may hypertrophy. 
Acromegaly is rare. It occurs slightly more frequently in men than in 
women. It begins at the age of 25 or 30, very insidiously. Twenty per cent 
of acromegalics are over six feet when the symptoms begin and fully forty 
per cent of the giants are acromegalics (Sternberg). Sometimes somnelence 
is the first symptom—and headaches are common throughout the course of 
the disease. Due to factors mentioned in the epitome of symptoms given 
above, the patients are forced to procure larger and larger hats, gloves, and 
shoes. Friends notice the facial deformities. The disease may last 20 to 30 
years; in some cases, with brain tumor, death follows in three to four years. 
The etiology or cause is usually associated with a tumor of the pituitary body 
—nearly always an adenoma, adenosarcoma or a sarcoma. The pituitary in- 
creases in weight greatly. Trauma (injury), the infections and emotional 
shock have preceded the onset of the disease. The enlarged hypophysis 
usually extends downward and forward as the sella turcica enlarges in like 
manner as shown by X-Ray plates or upon postmortem examination. In 
summary, acromegalia presents certain changes in appearance notably of the 
face, Ungers and feet. 
A-2 Gigantism is due to hyperpituitarism, or over-function of the hypo- 
physis. Uusually the person suffering from gigantism is over 6j4 feet tall. 
There is a disproportion between the various segments of the body. It 
begins before the epiphyses have fused to the diaphyses, and is therefore 
different from acromegaly in this respect. The lower extremeties may elon- 
gate—the person appearing as if on stilts (macrosketic type) or the arms 
may become longer (bradysketic type). Temporary strength may be observed 
at first, but sooner or later the individual suffering from gigantism becomes 
weak, bodily and mentally—and asthenic. They walk with difficulty, and they 
nearly always are impotent and sterile. 
Three varieties of forms are presented clinically: 
1. Gigantism with acromegalia. Resemble anthropoid apes. Fingers not 
sausage-shaped, for the development is in length more than in width. 
2. Infantile gigantism. Elongation of inferior extremities—with genu 
valgum. Genital organs infantile. Hairs do not appear as normally. Voice 
frail and childish. Feminine form of breasts (slight) ; abdomen (rounded) ; 
9 pelvis (broad). Cartilages persist in the adult and the epiphyses remain un- 
fused with the diaphyses. Gradually changed to acromegalia-gigantism. 
3. Gigantism. Sometimes occurs. The persons have a large skeleton, 
but enjoy good health. They are normal giants whereas the two varieties 
(1 and 2 above) were pathological or abnormal giants. However, the in- 
telligence is often mediocre; and sometimes impotence is a concomitant. 
Gigantism, of whatever form, about always occurs in the male; at 
puberty or before puberty. Death usually occurs in youth, due to pulmonary 
tuberculosis after emaciation and cachexia. Uusaully a tumor (as in acro- 
megaly) is found at autopsy, associated with an increase in the dimensions 
of the sella turcica. 
A-3 Pituitary InfantaJism is so uncommon that we will omit a discussion 
of this type of hypopituitarism or anterior lobe insufficiency. Suffice it to state 
that it is a general retardation of development, especially as regards genital 
growth. 
B-\ Dystrophy Adiposo-genitalis, the first of the pituitary syndromes, 
listed under “General Disorder of Nutrition,’’ was observed by Babinski in 
1900. It occurs in infancy, adult life or even at menopause. Two symptoms 
stand out pre-eminently: 
(1) Marked general obesity or “fattiness,” and 
(2) Delayed development or atrophy of the genitalia. 
Symptoms—Fat invades the whole body. 
Face large and rounded. Often cyanotic. Marked fatty hypertrophy of 
the breasts in women. The mammary glands atrophy, however. 
Relaxation of abdominal wall. 
Hips and buttocks sometimes enormous. 
Limbs resemble columns. 
Skin waxy white; hard, cold edematous and incompressible by the 
fingers. In this respect like myxedema (hypothyroidism). 
In male children the testicles stay infantile. Secondary sex characters 
are absent. In women the menses become irregular and later a condition of 
amenorrhea (lack of menstruation) ensues. Frigidity and impotence take 
place in men. 
The etiology of dystrophy adiposogenitalis is complex. The causes are 
many. There is evidence of thyroid and ovarian (or testicular) deficiency. 
Cushing believes the disease to be due to a lesion of the posterior lobe of 
the pituitary body. 
B-2 Pituitary Diabetes. Marie, in 1886, stated that one-half the cases 
of acromegalia showed pituitary glycosuira (sugar in the urine), which may be 
continuous or intermittent. The exact portion of the pituitary body which 
is responsible for this is as yet unknown. 
Pituitary polyuria has been noted. Canms and Roussy believe, after 
experiments on animals, that the water regulating centre is in the region of 
the infundibulum or tuber cinereum. 
The Clinical Aspects of Pituitary Diseases 
Concerning the disorders of this secretive gland of the head, the clinic 
has manifested that the five groups listed on page 25 of Dr. Cushing’s book 
are the most instructive. In very general terms hypophyseal implication may 
be listed under two heads: (1) “Those in which the gland was seemingly 
10 the primary seat of disease”; (2) ‘‘Those in which it was secondarily in- 
volved, usually by the direct compression of an adjoining part, or the more 
remote effects of a distant, cerebral lesion.” 
Cases may again be classified in general as Dyspituitarism; under which 
the implications may be graded according to the amount of secretion in 
relation to the normal; if over-secretion is shown the term hyperpituitarism is 
used; if the gland is under secreting the condition is called hypopituitarism. 
Quite evidently disease of the pituitary tends to produce a change in 
the metabolistic activity of the organism as a whole; this fact is important, 
not only in a clinical way as regards the health and happiness of the patient, 
but also from the point of view of research in the field of the factors con- 
trolling the development of the organism. Turning now to the examination 
of two cases, selected from a book written by Dr. Harvey Cushing, entitled 
“The Pituitary Body and Its Disorders,” a definite order will be followed 
in recording the data, namely: 1. Record of Case; 2. History; 3. Diagnosis; 
4. Prognosis; 5. Discussion. 
Case 2 (Surgical No. 25971) see page 36: 
1. Record of Case—“Typical recent hyperpituitarism of adult life (acro- 
megaly) with an actively-growing chromophobe struma, producing both pro- 
nounced neighborhood and general pressure symptoms. Operation. Death. 
Autopsy.” 
Symptoms of hyperpituitarism follow: Overgrowth, resulting in gigantism 
when process anterdates ossification of the epiphyses—typus Launois; result- 
ing in acromegaly when it is of later occurrence—typus Marie. 
2. History—1910. Seamstress, 25 years old was admitted; complaint, 
Amenorrhoea. Was one of a healthy family of twelve. Had been well 
except for single sickness in Russia seven years ago; in hospital then with 
‘‘headache, fever and blindness.” She regained her vision. Her menses began 
at 15—regular until her marriage, three years ago (1907). She dates existing 
malady 1907. Pregnant: temporarily blind in right eye. “Eleven months 
after her marriage the menses reappeared for four months, but since then 
amenorrhoea has been complete.” Two years ago an enlargement of nose, 
hands and feet was first noticed. Headaches from! onset, but now severe. 
3. Diagnosis—See history. Headaches occur in paroxysmal attacks 
several times a day, accompanied by burning flushes and occasionally 
by nausea, projectile vomiting, temporary amaurosis and relaxation of the 
sphincters. No loss of consciousness. Periods of diplopia and vision rapidly 
failing. Sweating profuse for two months, particularly at night, with itching 
and burning of the extremities. Drowsy. Yawns. Sleeps most of the time. 
Has had attacks of palpitation and polyuria. Habitually constipated. 
Physical exam.: Short (5 ft. 5 in.) overnourished woman, wt. 143 lbs. 
Expression is dull, stolid. She had normal heart and peripheral vessels; no 
arteriosclerotic changes. Skull was not particularly modified. Adiposity not 
a striking feature. Temperature slightly above nomal (99-99.6). 
Sugar assimilation not high. 
Thyroid is palpable, undersized uterus, only one small ovary is palpable. 
Marked pigmentation of the skin. 
4. Progonosis—Operation: “Hypophyseal decompression by the sublabial 
route with submucous resection of vomer. Terminal pressure phenomena of 
unsuspected intracranical extension of struma. Medullary failure on the 
following day.” 
11 5. Discussion—A postmortem examination showed that the patient had 
a tumor occupying the third ventricle of the brain; evidently produced in 
the hypophysis. Also a somewhat enlarged thyroid with a colloid goitre; 
ovaries are large, cystic and degenerated. Pancreatic islets numerous, large 
and the gland shows a fatty infiltration. Considerable persistent thymic tissue. 
Adrenals large. Fatty change in the liver. Small uterus. 
“Her luxuriant hair, moist skin, elevated temperature, normal sugar 
tolerance and the insignificant thermic reaction to an injection of anterior 
lobe extract all pointed to a state of hypophyseal hyper-activity.” 
Case 30. (Surgical No. 26068). See page 154. 
1. Record of Case—“Typical chronic advancing hyperpituitarism, (acro- 
megaly with the suggestion of gigantism) of fifteen years’ duration. Absence 
of objective neighborhood symptoms. Subtemporal decompression. Glandular 
therapy.” 
2. History—June 8, 1911, admitted for study. Forty-two years old, a 
collegiate instructor. Younger sister has been suffering for some years 
with headaches, has a changed contour of face and undershot lower jaw. 
Patient himself periodic headaches since early youth. Attacks of hay-fever. 
Mucous membranees particularly sensitive to certain odors. “As a young 
man he was delicate-featured and light complexioned, weight 140 lbs. in 1892, 
when he graduated with high classical honors and started his career as a 
teacher. He has since grown dark, heavy and taller, weighing now over 200 
lbs.” Married in 1898; no offspring. 
3. Diagnosis—Onset was insidious. His surgeon noticed it in 1896 when 
the patient was operated on for enlarged cervical glands. In 1900 intra- 
dranial discomforts pronounced. Since then he has taken pituitary extract, 
except between the years of 1904 and 1908, when he took thyroid extract. 
Headaches. No nausea nor vomiting. Complains of logginess. Low blood 
pressure. Progressive decline in libido sexualis for some years. Perspires 
freely. Overgrowth of bones as well as in their coverings. Head large. 
Nose shows the characteristic narrow bridge and wide nostrils. Lips are 
thick. Hands are spadelike. Feet large. Skin not pigmented but moist. 
Gained 60 lbs. since onset of malady. Temp. 97-98. 
4. Prognosis—Operation. A right subtemporal decompression was per- 
formed. Headaches still persist. 
5. Discussion—“At present the active process has subsided and the con- 
dition is verging toward hypopituitarism—at least on one side of the posterior 
lobe insufficiency, judging from the subnormal temperature, the low blood 
pressure, increase in sugar tolerance and the tendency toward adiposity. . . . 
The static headaches, invariably relieved by recumbency, are possibly due 
to the emptying of the fluid contents (cerebrospinal or venous) of the cranial 
chamber when the patient assumes an upright position.” 
Miscellaneous 
Pituitary Syndromes in Infections are sometimes alleviated by pituitary 
organo-therapy (extracts from the hypophysis of the ox is usually used) by 
producing: . 
1. Increase of arterial pressure. 
- -2. Increase of diuresis. 
-.,3. Degrease of tachycardia (~ rapid heart rate). 
4. Reappearance of sleep and appetite. Epinephrin or adrenalin (from 
the suprarenal bodies) is also often associated here. 
12 Treatment of Pituitary Syndromes: 
1. Organo Therapy. 
Posterior lobe extract. Average dosage, 0.10-0.40 centigrams, daily. 
2. Radio-theraphy. 
Some success has followed this method (Beclere and Jaugeas). 
3. Surgical Treatment. 
Nasal route is the best method of approach, but the fatality is still 
high. It may be indicated especially in acromegalia. 
From this abridged discourse on the nature and function of the pituitary 
body one may rightly infer that a vast field of research on this particular 
endocrine gland still remains. Already, however, we are far ahead of the 
“cold-in-the-head” theory. We know something of its physiological, pharma- 
cological and therapeutical actions; and of its diseased conditions. That a 
structure so small produces such relatively enormous influences upon the 
body merely emphasizes the ancient remark of David in Psalm 139, “I am 
fearfully and wonderfully made.” 
BIBLIOGRAPHY 
Allen, B. M.: Science (New Series), vol. 44, No. 1143. 
Allen, B. M.: Science, vol. 52, No. 1342. 
Atwell, W. G.: Science, vol. 49, No. 1254. 
Bassoe, Peter: Acromegaly. 
Beck. Harvey G.: Dystrophia Adiposogenitalis. 
Bell, W. Blair: The Pituitary. 1918. 
Cowdry, E. V.: Anatomy, Embryology, Comparative Anatomy and Histology of the 
Hypophysis Cerebri. 
Cunningham: Text Book of Anatomy. 5th Edition. 
Cushing, Harvey: The Pituitary Body and Its Disorders. 
Hammett, Frederick S.: The Pharmacology of Hypophyseal Extracts. 
Lewis, Dean: Physiology and Experimental Pathology of the Hypophysis. 
Macleod, J. J. R.: Physiology and Biochemistry in Modern Medicine. 3d Edition. 
Mason, F. Raoul: Endocrine Glands. 1922. 
Mathews, Albert P.: Physiological Chemistry. 3rd Edition. 
Osier, Sir William: Principles and Practice of Medicine. 9th Edition. 
Schafer, E. A.: The Endocrine Organs. 1916. 
Stohr, P.: Lehrbuch der Histoligie B. 15th Edition. 
Smith, P. E.: American Anatomical Memoirs, No. 11. 
Sollman, Torald: A Manual of Pharmacology and Its Application to Therapeutics 
and Toxicology. 1922. 
Swingle, W. W.: Journal of Experimental Zoology, vol. 43. 1921. 
Simonds, J. P.: The Pathological Anatomy and Histology of the Hypophysis. 
Tilney, Frederick: Contribution to the study of hte hypophysis cerebri with especial 
i eference to its comparative histology. Mem. No. 2, Wistar Ins. Anat. and Biol., 1912. 
Vincent, Swale: Internal Secretions and the Ductless Glands. 1922. 
13 MENDELIAN INHERITANCE IN MAN 
IT has been customary to employ all scientific deductions for the explanation 
of human phenomena. This, of course, is only natural for what we are 
ultimately interested in is how this mechanism works. In general, the 
laws of physics and chemistry explain to us the purely physical and chemical 
reactions which go on in the body. From physics we understand the mechanics 
of this machine, and its energy transformations. So we speak of the skeletal 
system as being a system of finely adjusted levers. From chemistry we under- 
stand how the chemicals we take in are transformed into others which we can 
use. In short, all branches of engineering, mechanical, chemical, and possibly 
electrical, are comprised in the human body. The laws of biology and psy- 
cology, the former derived from the study of animals and plants, the latter 
from the lower animals and man, have been profitably brought into use. From 
the study of these sciences have developed others which deal exclusively with 
human material, deriving their data from human experience past and present, 
individually and collectively, and dealing with the two forces, heredity and 
environment. 
We shall atttempt this morning to present a very brief sketch of the work 
already done on the explanation of the phenomenon of heredity in man by 
one of these principles. 
In 1858, Darwin published his “Origin of the Species” and included an 
outline for heredity together with variation to establish the doctrine of evolu- 
tion. He devised an ingenious theory which he called pangenesis, postulating 
that the different organs of the body gave off into the blood or other body 
fluids minute living particles which he called gemmules, and which he supposed 
to be capable of growth (and multiplication. The germ cells were supposed to 
have a special affinity for these gemmules, their function being to act asi store- 
houses for these bodies. During development the gemmules were sorted out, 
each kind determining the development of a part of the embryo into) the kind 
of organ from which it was derived. He had accepted the doctrine of the 
transmission of acquired characters which Erasmus Darwin, and later Lamarck, 
had postulated as the chief cause of organic evolution. Granting Darwin’s 
doctrine of Pangenesis, the explanation of the transmission of acquired char- 
acters followed very naturally but the difficulty lay in the artificial and im- 
probable nature of its fundamental assumptions. 
De Vries modified this doctrine and paved the way for Weismannism by 
eliminating the hypothesis of the centripetal flow of pangens and assuming 
that they were not given off by the cells of the body and stored up in thie 
germ cells but the germ cells were held to receive their store of pangens from 
antecedent germ cells. Weismann, however, was the first to vigorously oppose 
Lamarckism. In i892 appeared his “Doctrine of the Germ Plasm” in which 
he taught that the! germ plasm is a substance separate from the soma plasm 
which forms the organs of the body, that it is' in no way the product of Ithej 
body, although it is carried and nourished by the body. Germ plasm is handed 
on relatively unchanged from one generation to the next, part of it being 
14 transformed into soma plasm which differentiates in various way during em- 
bryonic development, but another part of it remaining undifferentiated in the 
germ cells to form the starting point of the next generation. It is the con- 
tinuity of the germ plasm that affords the basis of heredity. 
Th|e discovery which has meant most in the study of heredity is unques- 
tionably Mendel’s law. The product of years of research in the garden of the 
monastery of Briin, Austria, the principles enumerated by Mendel, owing to 
the fact that they were published in a little known journal, “The Proceedings 
of the Natural History Society” at Briin and in the excitement of the post- 
Darwinian controversy, failed to attract the attention of the scientific world 
until they were made known independently by three investigators, Tschermack, 
Correns and De Vries, in the year 1900. 
Mendel’s law includes two main principles, the principles of dominance and 
segregation. Characters were found to be present in opposing pairs, as dwarf- 
ness and tallness in peas. When pure dwarf was crossed with a pure tall, 
the offspring were all tall, in other words, tallness is the dominant and dwarf- 
ness a recessive character. 
DD RR 
FI Dr DR 
F2 DD DR DR RR 
3 1 
When the tall peas in FI were crossed, the F21 generation gave tall and shor,t 
peas similar to the grandparents in the proportion of three tall to one short. 
When these were analyzed it wa's found that one-half of the crop were 
similar to the parents or heterogeneous, containing characters for both tallness 
and shortness in the germ plasm; one-fourth of the crop were similar to the 
tall grandparent and bred only tall peas; one-fourth similar to tihe short 
grandparent and bred only short peas. In the F2 generation it is seen tha,t 
the separate characters present in the germ plasm cells of the parent must 
have been separated and reunited. This is Mendel’s law of segregation. 
But it is not often an easy task to show this, especially in man, whlefre 
complete dominance is not a general phenomenon. “Contrasted characters,” 
says S. J. Holmes, “frequently blend in the first generation and many grada- 
tions occur between complete dominance and a strictly intermediate condition, 
but this in no wise alters the fact of segregation, although it may rendter 
segregation more difficult to establish.” 
Parallel with and entirely independent of the function of Mendel’s laws 
the study of cytology and especially of the necleus and its contents give us the 
mechanism by which inheritance is maintained. We have as proof that 
heredity is determined by the nucleus and the chromatin material in it: the 
essential value of the nucleus in metabolism; the equivalence of the germ cell 
nuclei; the process of mitosis, the enucleate experiments and experiments with 
polyspermic eggs. In spite of this, Godlewski’s classic experiment by which 
an offspring with maternal characteristics was obtained from an egg deprived 
of its nucleus and fertilized seems to point to the contrary. Recent investiga- 
tors, however, have attempted to explain this by saying that the mitachondria 
in the cytoplasm have a function similar to the chromatin in the nucleus as 
bearers of heredity. 
15 We are handicapped at the outset in man by having no experimental evi- 
dence, by the many difficulties of getting correct statistics, and by the frequent 
pitfalls offered to the unwary in their interpretation. The genealogies on 
which we must depend, the imperfect records of births and deaths, erroneous 
diagnosis, and sometimes, the uncertainty of the paternity of a given child, 
which is frequent among mental and moral defectives, hinder correct inter- 
pretation. Still other difficulties exist. For example, the very limited number 
of children of any given couple, the possibility of escaping the environmental 
stimulus which would call forth a trait, and then the peculiar character of 
certain traits, peculiar in that they appear only late in life. Furthermore, the 
study of inheritance is made extrmely difficult because many of the traits 
are due to multiple determiners. Morgan says “Often the best we can do in 
the case of man is to try to find the simplest Mendelian formula to which the 
evidence will fit. If one factor difference will not suffice, then two must be 
tried: if two will not do, then three must be tried, etc.” However, numerous 
human traits are already known which give strong evidence of being trans- 
mitted in accordance with this law. A few of these will be discussed in detail 
and the rest tabulated. 
Among the clearest cases of Medelian inheritance in man is the inheri- 
tance of certain malformations of the hands and feet. Among the first of 
these families to be investigated was one in Pennsylvania by Dr. Farabee in 
1903. Though reports and histories had been recorded of such conditions since 
1857, Farabee’s report, we may say, marks the first investigation on the subject 
from the Mendelian standpoint. 
The condition he described is known in the current literature as brachy- 
ohalangy or brachydactyly. This is a condition in which the middle row of 
phalanges, exclusive of the thumb, and big toe, is aibortive. Dr. Farabee was 
under the impression that this row was entirely absent but Dr. Drinkwater, 
in his later analyses by means of radiographs, proved that it was present. 
In some cases ankylosis had occurred with the distal phalanx, so that it seemed 
to be missing. This, naturally, would result in an abnormal shortening of the 
fingers and toes to about one-half normal length. There is a corresponding 
shortening in the length of the thumbs and big toes, the relations remaining 
the same as in the normal hand. The general appearance of the hand is short, 
broad, thick and pulpy. This, in general, is the character of the malformation 
which is inherited, but there are many minor variations in the somatic appear- 
ance of this character. 
These variations occur in the number and comparative size of the abortive 
middle phalanges, in the absence or presence of distal phalanges, in the char- 
acter of the malformation of the thumb and big toe, in the absence or presence 
of finger nails and im the corresponding shortening of the metacarpals and 
metatarsals of the long bones of the upper and lower extremities evident in the 
span of the arms and in the shortening of the stature of the individual. The 
latter variation does not occur in members of the same family but in different 
families studied. 
It is noticed that the malformation is always bilaterally symmetrical and 
when the feet were also examined, they showed corresponding abnormalities. 
The carpel and tarsal bones are not affected in any case. 
In England and Scotland Dr. Drinkwater, in his extensive studies, has 
come across the same conditions. It was first brought to his attention in 1908. 
16 A very interesting connection was established between his “second 
brachydactylous family” and Earabee’s family in America. One of the affected 
individuals of his second generation migrated to America and became the 
father of the line of Farabee’s family- Dr. Drinkwater also came across a 
condition that is not so marked where the shortening has not gone so far. 
This condition he called minor brachydactyly. Here there is no ankylosis and 
the relations can be seen from the diagrams. 
This condition is transmitted by both sexes and is not confined to the 
white race. A similar malformation has been reported by H. M. Smith in a 
negro family and traced through four generations. The only accompanying 
character in some cases is the abnormal shortness of stature. 
Though the discussion of the origin and cause of the malformation is not 
in direct line with the subject of this paper, we may say that Dr. Drinkwater 
believes it to have occurred as a “sport.” The cause of this is probably a 
premature ossification, for where ossification is complete in the normal indi- 
vidual at the age of twenty-one, in some of the abnormal cases, the ossification 
is complete as young as twelve. The absence of epiphyses or the early union 
at the epiphyses or ankylosis, and a slight shortness in the shaft of the bone 
are other causes. 
From the study of the inheritance of this malformation in several families 
through several generations, it seems to be transmitted as a Mendeliajn 
dominant. There is perfect segregation of the character, i.e., it is either 
inherited in full or not at all and is transmitted only by the affected individuals, 
for in no case has the character cropped up in the family of a normal indi- 
vidual whose parent was affected. This was well brought out in Farabee’s 
family where in the third generation two normal cousins married and had only 
normal children, showing that the union of two recessives does not give ai 
dominant. 
If the character is a Medelian dominant, then SO per cent of the offspring 
should be normal and 50 per cent abnormal, provided the abnormals marry 
normal individuals. 
DR X RR 
DR + 2 RR 
No. of 
Nor- 
Abnor- 
Per- 
Investigator 
Offspring mal 
mal 
cent 
Dr. Farabbee . ..., 
69 
33 
36 
52.17 
Dr. Drinkwater.. . 
1st Bracydactylous 75 
36 
39 
52 
a u 
I Minor Brachydactylous.. 47 
26 
21 
44.6 
u u 
...II Minor Brachydactylous.. 19 
10 
9 
47.37 
a u 
... II Brachydactylous 98 
48 
50 
51.02 
a u 
...III Brachydactylous 42 
17 
25 
59.52 
Average Percent.... 
.51.11 
Another hand anc! foot deformity which by soxne is claimed to be a case 
of Mendelian inheritance is the case of split hand and split foot. This is 
usually a symmetrical clefting of the foot with a complete syndactyly or union 
of the remaining two groups of toes and an irregular though often symmetrical 
deformity of the hands. As in the preceding malformation there are many 
17 minor somatic variations, but the general type of deformity is the same 
throughout, the variations being one of degree and not of kind. 
The following are counts of split foot families by different investigators. 
Investigator 
No. of 
Offspring 
Normal 
Abnormal 
Percent. 
Parker & Robinson 
32 
16 
16 
50% 
Lewis & Embleton 
76 
44 
32 
42.1% 
Fotheby 
26 
16 
10 
38.5% 
Mayer 
18 
12 
6 
33p$% 
Of the normal characteristics of man which mendelize, eye-color is 
perhaps the best established. The color of the eye acts as a unit factor, 
double in the zygote and separted in the germ cell into its original components. 
According to the kinds, of germ cells which may then combine we find eye- 
color of either a homozyggus or heterozygous character. If brown meets 
brown an individual is formed with a double factor for brown. Again, jf 
brown meets blue, we get an individual with brown eyes who has in his germ 
plasm a factor for blue. 
As can be surmised from the above statements, evidence points to the 
fact that the brown color is dominant to gray, blue or albino. This is easily 
understood when we recall that the brown color of the eye is formed by 
melanic pigment in the front of the iris. Blue-eyed individuals lack this coat. 
They have a dark purple cojSt, on the inner surface of the iris. In the case of 
the albinos, the coat behind the iris which gives a blue color when light is 
transmitted through it, is also lacking. The pink eye-color is -due to the 
blood capillaries present, which are not obscured by any pigment and which are 
seen through the semi-transparent fibrous tissue as pink. 
Sometimes melanic pigment is scattered in granules in the front of the 
iris. The few granules upon the background of pigment which shows as blue 
gives gray eye-color. We also find, occasionally, that the iris contains a slight 
amount of yellow pigment which is presumably a fat pigment or lipochrome. 
This, with a blue background, gives green eye-color. We can sum all the 
evidence up by giving the nature of the mating. 
Duplex 
Duplex 
All Duplex 
Duplex 
Simplex 
50% Duplex, 50% Simplex 
Simplex 
Simplex 
25% Duplex, 25% Nulliplex, 50% Simplex 
Nulliplex 
Nulliplex 
All Nulliplex 
Duplex 
Nulliplex 
All Simplex 
Simplex 
Nulliplex 
50% Simplex, 50% Nulliplex 
Duplex=DD Brown 
Simplex=DR Brown 
Nulliplex—RR Blue 
The lack of the brown coat in the case of blue eyes is interesting in the 
light of history. In Northwestern Europe blue, gray and yellow-blue eyes 
are predominant. By noticing the. distribution of eye-color the migrations of 
people can be traced. In the Spey valley of Scotland, we are told, the density 
of pure blue eyes is high—probably due to the Norse invasion at that point.* 
Pigmentation of eyes and skin is also presumed to better fit a child for life 
in the tropics or in the bright sunlight. 
18 An inheritance, similar to that of eye-color, is demonstrated in the case of 
skin pigmentation. Four kinds of pigment, black, yellow, red, and white are 
involved. In a slightly tanned white person the distribution of the pigment 
as shown when determined by a color top is 
B 
Y 
R 
w 
8 
9 
SO 
33 
In a very dark negro it is 
75 3 20 2 
The dark pigment is a melanic pigment found in fine granules in the deeper 
layers of the stratum mucosum of the skin. The pigment granules are dis- 
continuous and the grades of color may be due to more or fewer elements of 
the so-called mosaic. The difference in negro, mulatto and brunet may be the 
difference in the point at which the melanogenetic process is stopped. The 
yellow and-red pigment is considered as a lipochrome. The white color is 
due to the opacity of the skin itself. 
In the case of the typical Causasians, it has been found that when both 
parents have blond complexion or fair skin all of their children will have 
fair skin. A brunet who has the double factor for dark pigmentation when 
mated with a blond, will have only intermediate and brunet offspring. Thus 
blond is seen to be the recessive character. The brunet coloring, if present 
dominates and there seems to be no blending of the colors as is the case in the 
FI generation of the red and white mirabilis flower blending to give a pink 
color. 
If this is so, then the problem of explaining the significance of inter- 
mediate color in the case of the white, arises. Sometimes this color has been 
found to act as a simplex, or heterozygous condition. In skin color there is 
more than one color factor involved. Therefore, in most of the literature we 
find that intermediate is termed epistatic to blond and hypostatic to brunet. 
When the determiner for intermediate is present in the germ cell and is linked 
with the factor for blondness, it either acts with blondness as part of the 
unit character and therefore gives no sign in a resulting soma of its presence, 
or again it may react as a separate unit aind as a consequence obscure the 
factor for blond. In a similar manner intermediate is linked with brunet in 
the germ cell. In this case, brunet is the darker pigmentation and will obscure 
the intermediate unless the intermediate works as a separate unit. 
The confusion concerning intermediateness arises because we do not know 
exactly how or why differences in amount of pigmentation occur. Pigmenta- 
tion stops at a certain point which may be determined by an hereditary unit 
which halts melogenesis at that point. We do not know what this hereditary 
unit is. or how it works. It has been thought that some such retardation or 
acceleration functions in giving to negro and white a different pigmentation. 
However, there is certainly a wide difference between the two, not a mere 
shading from one to the other, as in the case of negro-white crosses. What 
the difference is, is not known. 
A very few years ago it was' thought that the mulatto illustrated a case 
of so-called “blended” inheritance and once formed a constituted a distinct 
type. We find that, on the contrary, the original grades of heavy and slight 
melanogenesis segregate in the germ cell according to the Medelian formula. 
This segregation is often not entire because of the multiplicity of units for 
skin pigmentation. Thus the original color characteristics are restored in 
19 almost their original purity in the gamete. To sum up the evidence briefly, 
when one parent is white and the other is as dark as a full-blooded negro, the 
offspring vary in color from black to as light as most Caucasian skin and 
follow the Mendelian principle. Thus in rare instances from the hybrid in a 
third or later generation a typical Caucasian, physical! and mentally, may 
result. 
Inheritance of albinism also follows the same laws. Albinism has been 
found to be a recessive character. It occurs as a result of consanguineous 
matings, at which time two recessive traits come together. It is the product 
of an albinism mating and also occurs when the two strains have a marked 
absence of dark pigmentation. 
Pathological conditions offer a much greater field for the indication of 
how Mendelian inheritance operates in man. Some conditions, as haemophilia, 
which is a proneness to hemorrhage and a difficulty in blood clotting, are sex- 
linked. These presumably have a determining factor linked in the X or sex 
determining chromosome. We know that a haemophilic person mated with a 
normal person has sons of whom half the number are haemophilic. None of 
the daughters have this condition, but one-half carry the defect in their germ 
plasm, which they can transmit to their sons. Normal sons do not transmit 
this characteristic. Predisposition to various diseases and the occurrence of 
various disease during the early or late years of an individual are also inherited 
in Mendelian fashion. These are not sex-linked. The literature on the 
subject is vast, but space does not permit us to describe them here. Some 
will be found in our table. Others can be studied by referring to the biblio- 
graphy appended. 
Perhaps what is more interesting to us as students of the human race is 
the inheritance of mental characteristics. Though there is a great deal of con- 
troversy in this field, a few general conclusions may be drawn from the large 
amount of data available. It must be remembered that the attempts to make 
these characters mendelize is of comparatively recent date. It has long been 
known that mental deficiencies are transmitted from parent to child, butt no 
precise rules had been found. There is no doubt that all mental deficiencies 
are not due to environment alone. In the case of feeblemindedness, it has 
been shown through thorough psychological investigation of the individual 
and his family, that feeblemindedness is inherited. Since they tend to marry 
their own kind, the results of such unions to society can well be imagined. 
The most fruitful study along this line has been done by Dr. Goddard on 
the Kallikak family. One branch of the family has been prominent in all the 
intellectual and social walks of life, while the other branch presents a most 
degenerate class. The degenerate branch of the Kallikaks had produced to the 
time of Dr. Goddard’s publication in 1912, 1146 individuals, 262 of whom 
were feebleminded, 197 abnormal and the rest still undetermined. Alcoholism 
and prostitution are very common. This condition was considered by Goddard 
to be transmitted as a simple Mendelian recessive, i.e., the mating of twfo 
feebleminded people would give feebleminded offspring. This was modified 
by Danielson and Davenport in their report of the Hill Folk in 1912. They 
considered feeblemindedness as being more of a legal or sociological term and 
according as to whether the individual possessed a certain set of socially 
important traits he was either feebleminded or not. So if we mated two 
people with different kinds of feeblemindedness, i.e., people who lacked dif- 
ferent sets of socially important traits, we would get some normal offspring. 
20 It has been claimed by Heron and Pearson that feeblemindedness is not 
inherited in the Mendelian way because we get all gradations from lowest 
forms of idiots to high grade morons. This does not follow, for the variation 
is one of degree and not of kind—so that we get different somatic modifica- 
tions resulting. 
Very closely allied to feeblemindedness is hereditary epilepsy. How it is 
related to the inheritance of feeblemindednss is not known, but epileptic off- 
spring occur when two feebleminded people are mated. So the conclusion 
that it is inherited as a simple Mendelian recessive is not adequate. Probably 
as Davenport and Weeks pointed out, epilepsy and feeblemindedness are due 
to “the absence of a protoplasmic factor that determines complete nervous 
development and that the condition is recessive to the normal.” 
Even less clear is the case of insanity. In the first place, there is a, great 
controversy over the percentage dne to inheritance and the percentage to 
environmental influences, as diseases, injury, severe mental shock, worry, child- 
birth, syphilis and alcoholism. The percentages vary from ten to ninety per 
cent, but the concensus of opinion among modern writers seems to be that 
insanity is largely inherited. Since it does not always become manifest until 
after the period of adolescence and often during middle age and old age, the 
way in which it is transmitted is harder to follow. There are so many dif- 
ferent forms of insanity, that we cannot speak of its being inherited as a unit 
character due to defect or loss of a single character in the germ plasm for 
that woud be “on par with ascribing all kinds of heritable physical anomalies 
to the same cause.” Rosanoff and Orr who made the first serious attempt to 
study insanity from the point of view of Mendelism, came to the conclusion 
that it behaves as a Mendelian recessive character but they claimed that 
various neurophathic taints dominant to the normal may be recessive to other 
taints. This would make the Mendelian formula more elastic and increase the 
difficulty of proving the inheritance Mendelian. This Holmes thinks is prob- 
ably the best explanation, so far, of the mechanism of the inheritance of mental 
deficiencies, for he says, “Imperfect dominance is sufficiently plentiful among 
organisms in general to make us expect it more or less frequently in the 
inheritance of neuropathic traits.” 
Associated with these characters is the inheritance of the state of mind 
which leads one to become a criminal. It is true that the environment has' a 
great deal to do with the turning out of the ultimate criminal, but we must 
not forget the equipment with which he is thrust into his environment. 
Through studies of families of criminals it can be easily seen that there is 
always some neuropathic taint which runs in the family and manifests itself 
in many different ways. Though the theories of the positive school that born 
criminals are ataval reversions to the ferocious lower beasts have been 
repudiated, much of what appears to be atavism may result from arrested 
development due to diverse pathological causes. One of the most enlightening 
works on the subject is the history of the Juke family begun by Mr. Dugdale 
and completed by Dr. Eastbrook. Cases of prostitution, pauperism, crim- 
inality and other forms of degeneration, are very common. The born crim- 
inal is very often epileptic or feebleminded. Though nothing definite can be 
known concerning such a complex character, no one will deny that it rests on 
a fundamental basis of inherited defect of some sort. 
Since it has been shown that defective mental traits are inherited in some 
way, possibly Mendelian, can it also be shown to be the case in the inheritance 
21 of superior mental ability? From the extensive work done by Galton on 
genealogies of famous men we can draw the conclusion that superior mental 
ability is inherited. But how is very difficult to ascertain since mental traits, 
as has been seen, do not present the sharply definable and discreet features 
often characterizing the physical peculiarities of the body. Davenport and 
Hurst, from their investigations, place certain intellectual accomplishments 
in the category of recessive Mendelian characters, but others think that it 
behaves as a Mendelian dominant, to inferior mental ability. 
The great role played, by environment or the existing social order must 
not be forgoltten, when the subject of greatness is discussed. No one will 
deny that many' men have died unknown for the lack of the proper environ- 
ment which would have brought out their particular genius. The fact that 
inventions and scientific conclusions are invariably arrived at by more than 
one person independently at the same time is sufficient proof that social evolu- 
tion has reached the stage where that particular thing, whether object or idea, 
was to beffiorn. 
From the study of the inheritance of mental traits, the great problem 
facing modern society becomes very evident. Is it because of sentiment or 
insufficient education that we keep on fostering the feeble-minded and delin- 
quents, allowing them to propagate at their own free will and then supporting 
them afterwards by contributing great sums which might be much more 
profitably spent on education? Mr. Dugdale estimated that the Jukes have 
cost the state over $1,308,000.00 up to 1902. What is to be done about this? 
Are we to go on or are we to come out and speak for a purer and more 
efficient race? That is the task of the Eugenist and can only be arrived at 
through the popularization of the results of the investigations on heredity. 
Traits Shown to Be Inheritable in Man 
Dominant 
Congenital cataract—condition of opacity of lens of eye which produces 
partial or total blindness. 
Retinitis pigmentosa—pigmentary degeneration of retina also involves 
atrophy of the optic nerve. 
Hereditary night-blindness (hemeralopia)—only can see in brightest light. 
Achondroplasy—abnormally short limbs with normal head and body. 
Keratosis—thickening of epidermis. 
Epidermalysis—excessive formation of blisters. 
Hypatrichosis—hairless, toothless condition. 
Diabetes insipidus. 
Diabetes mellitus. 
Ordinary (not Gower’s) muscular atrophy. 
Glaucoma—internal swelling and pressure of eye-ball. 
Displased lens. 
Coloboma—open suture in the iris. 
Spottedness of hair coat. 
Corneal opacity. 
Huntington’s chorea. 
Recessives 
Albinism. 
Certain forms of insanity. 
Hereditary feeble-mindedness. 
22 Chorea (St. Vitus’ dance). 
True dwarfism. 
Alkaptonuria (urine darkens after passage). 
Alcoholism and criminality where based on mental deficiency. 
Hereditary hysteria. 
Multiple sclerosis (diffuse degeneration of nervous tissue). 
Friedrich’s disease (degeneration of upper part of spinal chord). 
Merriere’s disease (dizziness and roaring in ears). 
Thomsen’s disease (lack of muscular tone). 
Hereditary ataxia. 
Tendency to become hard of hearing with increased age. 
Non-resistance to tuberculosis. 
Sex-Linked 
Color blindness. 
Haemaphilia. 
Nearsightedness (sometimes). 
Neuritis optica (progressive atrophy of optic nerve). 
Gower’s muscular atrophy. 
Some forms of night blindness. 
Ichthyosis—peculiar scaly condition of skin in some cases. 
BIBLIOGRAPHY 
Bateson, W.: Mendelian Heredity and Its Application to Man. 1906. p. 157. 
Boas, H. M.: Inheritance of Eye Color in Man. Amer. Journal Physiol. Anthropol., 
1919, pp. 15-20. 
Brandeis, J. W.: A Note on Amaurotic Family Idiocy. N. Y. Medical Journal, 
vol. 107, p. 121. 
Carruthers, J. F.: Retinitis Pigmentosa Lanat. June 24, 1916, pp. 12-62. 
Castle, W. E.: Genetics and Eugenics, pp. 15-20. 
Church and Peterson: Nervous and Mental Diseases. 
Clarke, E. L.: Amer. Men of Letters, Their Nature and Nurture, 1916. 
Conklin, E. G.: Heredity and Environment in Development of Man, 1915. 
Davenport, C. B.: Heredity in Relation to Eugenics. 
Davenport, C. B.: Feebly Inherited Nomadism, 1915. 
Davenport, C. B.: Heredity of Skin Color in Negro-White Crosses, 1913. Carnegie 
Inst., Wash., Publ. No. 188, pp. 1-106. 
Davenport, C. B.: Heredity of Constitutional Mental Disorders, 1920. 
Davenport, C. B.: Degeneration, Albinism and Inheriting. N. S. 28. 
Davenport, C. B.: Naval Officers—Their Heredity and Development, 1919. 
Davenport, G. C. & C. B.: Heredity of Hair Color in Man. Amer. Nat. 1909, 
xiiii; 1908, xiii, p. 341. 
Davenjport, G. C. & C. B.: Heredity of Skin Pigment in Man, p. 454. 
Defendorf & Kralpin: Clinical Psychiatry. 
Dickey, J. L.: Cataractous Families. Journal Amer. Med. Assn., vol. 55, p. 820; 
vol. 66, p. 2113. 
Drinkwater, H.: Account of a Family Showing Minor Brachydactyly. Journal 
Genetics, 1912-13. Also 1913-14. 
Drinkwater, H.: A Brachydastylous Family. Proc. Royal Soc. of Edin., 1908. 
Drinkwater, H., and Cragg, E.: A Second Brachydactylous Family. Journal Genetics 
1914-15. 
Drinkwater, H., and Cragg, E.: Hereditary Absence of Phalanges Through Five 
Generations. 1 
Dugdale, R. L.: The Jukes. ( 
East, E. M.: Mendelian Notation as a Description of Physiological Facts. Amer. 
Nationalist. 1912, xlvi. I 
23 East, E. M.: Mendelian Interpretation of Variation That is Apparently Con 
tinuous, 1910, Amer. Nat., vol. xliv, pp. 65. 
East, E. M., and Jones, D. E.: Inbreeding and Outbreeding—Their Genetic and 
Sociological Significance, 1919. 
Eastbrook, A. H.: Jukes in 1915. 
Farabee: Inheritance of Digital Malformation in Man. Harvard Univ. Peabody 
Museum of Amer. Archaeology Paper, vol. Ill, No. 3. 
Galton, F.: Average Contribution of Each Ancestor to Total Heritage of Offspring. 
Proc. Royal Soc. of London, 1897, LXI. 
Galton, F.: Hereditary Genius. 
Galton, F.: Inquiries into Human Faculty. 
Galton, F.: Noteworthy Families. 
Goddard, H. H.: Kallikak Family—Hereditary Feeblemindedness. 
Goddard, H. H.: Feeblemindedness—Its Causes and Consequences. 
Gossage, A. M.: Inheritance of Certain Human Abnormalities. Quart. Journal 
Med., 1908, p. 331. 
Guyer, M. F.: Being Well Born. 
Holmes, S. J.: Trend of the Race. 
Holmes, S. T., and H. M, Loomis: The Heredity of Eye Color and Hair Color 
in Man. Biol. Bull. XVIII, 5-15, Dec.. 1909. 
Home, Lucien: Eugenics Record Office Bull. 21, 1921. Cold Spring Harbor, N. Y., 
Book of Reference. 
Hurst, C. C.: Mendel’s Law of Heredity and Its Application to Man. Inheritance 
of Eye Color in Man. Proc. Roy. Soc. vol. 80B. 
Hurst, C. C.: Inheritance of Eye Color in Man. Prac. Roy. Soc., vol. 80B, 
Jordan: Heredity of Richard Roe 
Kellogg, V.: The New Heredity—Atlantic Monthly, Nov., 1922. 
Kraft, Ebing: Text Book of Insanity. 
Lewis, I.: Split Hand and Split Foot Deformities. Their Types, Origin and Trans- 
mission. Biometrike, vol. IV., 1908. 
McDowell, E. C.: Multiple Factors in Mendelian Inheritance Journal Exp. Zool, 
1914, xvi, p. 177. 
Morgan, T. H.: Heredity and Sex. 
Morgan, T. H.: Physical Basis of Heredity. 
Morgan. T. II.: Some possible Bearings of Genetics on Pathology, Middleton Gold- 
smith Lecture, 1922. 
Nettleship, E.: A History of Congenital Stationary Night-Blindness in Nine Con- 
secutive Generations. Opth. Soc. Trans, xxvii, I9O7. 
Nettleship, E.: Cases of Color Blindness in Women. Opth. Soc. Trans, xxvii, 1905. 
Nettleship, E.: On Heredity Forms of Cataract. 
Nettleship, E.: On Retinitis Pigmentosa and Allied Diseases. 
Nettleship, E.: Three New Pedigrees of Eye Disease. Opth. Soc. Trans, xxviii, 1908. 
Nettleship, E., and 
Ogelvie, F. M.: A Peculiar Form of Hereditary Congenital Cataract. Opth. Soc. 
Trans, xxvi, 1906. 
Newman, H. H.: Five Generations of Congenital Stationary Night-Blindness. Jour- 
nal Gen. 3, 1913-1914. 
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Smith, H. M.: Congenital Digital Malformations in Negroes, Amer. Antrhopologist, 
Vol. 6, p. 479. 
Sturtevant, A. 11.: Effects of Selection, 1918. 
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129-133. 
Eugenics Record Office Bulletins. 
No. 1. Goddard—Heredity and Feeblemindedness. 
No. 4. Davenport and Weeks—A First Study of Inheritance of Epilepsy. 
No. 5. Rosanoff and Ott—A Study of Heredity in Insanity in the Light of the 
Mendelian Theory. 
24 STRUCTURE, DEVELOPMENT, AND FUNCTION 
OF HEMOLYMPH GLANDS 
THE hemolymph glands have never been the object of intensive research. 
Lately, however, they have gained increased significance due to their 
extraordinary hemolytic action and their compensatory reaction after 
splenectomy. 
I. Structure 
The structure of a hemolymph gland resembles in several respects that 
of the ordinary lymph gland. It has a capsule of fibro-elastic tissue with a 
few unstriped muscle fibres; trabeculae of connective tissue extend from the 
capsule into the node dividing it into nodules; fine strands of connective 
tissue are then given off which enter the nodules and form a dense syncytial 
network—the supporting structure of node. Finer strands of connective tissue 
extend into the blood sinuses and are instrumental in retarding the flow of 
blood. Lymphoid tissue is also present either in large masses nearly filling 
the entire node, or as small patches found here and there. Cortical nodules 
with germinal centers where active mitosis is going on may also be present. 
Here and there amongst the lymphocytic mass are seen large mononuclears, 
polymorphs, taking all three stains, and rarely a megakryocyte or a poly- 
karyocyte cell. Some investigators would also include nucleated red blood 
cells in this list. 
The large mononuclears are especially interesting, since a great number 
of them both within the blood sinuses and among the lmphoid mass are filled 
with an ingested erythrocytic content. Their nature and significance will be 
discussed more fully under the heading of the functions of the hemolymph 
glands. The mononuclear easinophiles described by some observers as 
being present, are probably the phagocytic mononuclears with eosin stain. 
Nucleated red blood cells have also been identified by some in the interior of 
the large mononuclear cells. Meek states that he has observed in the hemo- 
lympth gland of the pig (in the human but very rarely), in their blood 
sinuses, nucleated red blood cells. In listing the cells of the hemolymph gland, 
the stellate cell of the connective tissue must also be mentioned since it has 
been said to be an important phagoytic agent of the gland. 
Afferent and efferent lymph vessels and intranodal lymph sinuses may or 
may not be present. The intranodal lymph sinuses may or may not com- 
municate with the blood sinuses. It has already become known to you that 
the main difference between the lymph gland and hemolymph gland is that 
in the latter the subcapsular sinues and the intradodal sinues are filled with 
erythrocytes instead of lymph. The subcapsular sinues is a space separating in 
a crude, irregular, manner the periphery of the lymphoid mass from the 
connective tissue capsule. The smaller intranodal sinuses also lie between the 
lymphoid masses and the strands of connective tissue penetrating into the 
25 interior of the node; they communicate with the subcapsular sinus. Our data 
points to the fact that the sinuses are lined by endothelium, which is nothing 
more than a continuation of the capillary wall. Other views held are that 
the sinuses are lined by a fenestrated syncytial structure or that they have 
no lining at all; i.e., they are cavernous and are surrounded on all sides by 
the lymphoid mass. 
The circulation within the node of the blood, from its entrance by afferents, 
to its exit by efferents, is somewhat as follows: The number of small arteries 
entering the hemolymph gland varies. Several may pierce the capsule or only 
one may enter the gland through the connective tissue at the hilum. The 
afferent artery follows the course of the trabeculae, becoming smaller and 
smaller in diameter; when it has reached the periphery of the lymphoid mass 
it dilates to become the subcapsular sinus; smaller dilated sinuses are given 
off from the large sinus which enter the interior of the node. The medullary 
blood sinuses are therefore the terminations of the arterial capillaries and 
the beginning of the venule capillaries. From these sinuses, venules are 
formed which unite to form the vein which leaves at the hilum. Because of 
the dilated condition of the capillary walls the blood sluggishly percolates 
through the sinuses, taking up at the same time leucocytes and waste material. 
Lewis and others have observed normoblasts within the blood sinuses; this, 
however, is still doubtful. 
Warthin, although he does not regard his classification of H. L. N. as 
absolutely correct, believes that the one he proposes is the clearest possible 
under the circumstances. Thus, he would call the glands under discussion 
hemolytic glands because of their hemolytic function and further subdivide 
them as follows: 
1. With blood sinuses only. 
A. (Splenolymph). 
B. (Marrowlymph). 
2. With blood and lymph sinuses not communicating (hemolym- 
phatic). 
3. With blood and lymph sinuses communicating within the node 
(hemolymph). 
Before concluding the statements concerning the structure of the hemo- 
lymph glands it would be advisable in order to bridge over the gap between 
the structure and development, to note the presence in some of them of a 
tissue which presents itself perhaps as evidence that it was the forerunner 
of the hemolymph gland. This is adipose tissue. 
II. Development of Hemolymph Glands 
The two ideas concerning the development of hemolymph glands are: 
1. Are hemolymph glands organs sui generis and if so from what are 
they developed? and 
2. Are hemolymph glands developed from lymph glands and if so in 
what manner? In this connection the theories advanced by the four investi- 
gators, Warthin, Meyer, Drummond and Sabin will be taken up in order. 
(1.) Warthin, who has done more constructive work on the study of 
hemolymph glands than any one else states that these glands are organs sui 
generis and are developed in adipose tissue in the following manner. In the 
prevertebral fat there appear certain fat lobules which stand out from the 
26 rest in having a more definite capsule of connective tissue and a richer 
vascular supply. After splenectomy he noticed that the intralobular fat 
capillaries became dilated so as to form a small sinus. The bordering fat 
cells lost their adipose inclusion and became converted into reticular connec- 
tive tissue cells which surrounded the capillary. Lymphocytes passed by 
diapedesis from the capillary into the reticular mesh-work, and there mul- 
tiplied. By further fat absorption and sinus formation the structure of an 
adult hemolymph node was produced, the peripheral and central blood sinuses 
being formed by the dilated capillaries. If later on the lymphocytic produc- 
tion was very great, then the diameter of the capillaries was reduced greatly 
in size, and an ordinary lymph gland was produced. 
(2.) Meyer, another intensive research worker on hemolymph glands, 
gives the following description of the formation of hemolymph nodes from the 
mesenchymal tissue of the embryo. In a subcutaneous portion of the fetus 
he found first a syncytial structure, condensations of the mesenchymal tissue. 
The cell outlines of the syncytial mass cannot yet be made out. Around this 
condensed mesenchymal portion appears a space which has no connection with 
any part as yet of the vascular system. Outside of this space there appears 
another circular region of condensed mesenchyme which represents the anlage 
of the capsule of the mature node. No capillaries or erythrocytes have yet 
appeared. Later on a few distinct polygonal cells can be seen in the center 
of the mesenchymal mass and as time goes on cell outlines become more and 
more distinct. The mesenchymal differentiation did not take place in or 
among a plexus of blood vessels. At a little later stage there appears in the 
perinodal space numerous erythrocytes and lymphocytes. Extra-nodal capil- 
laries and arterioles penetrate the perinodal condensation of mesenchyme, 
enter the perinodal space and sometimes the node itself. The fetal node now 
resembles an adult hemolymph node except for the absence of a capsule. The 
peripheral blood space is irregular and has invaginations both into the node 
and into the surrounding mesenchyme, simulating the appearance of blood 
vessels. Later on a capsule is formed from the surrounding condensed 
mesenchyme and the erythrocytes may penetrate into the parenchyma mingling 
with the lymphocytes. Larger arterioles now penetrate the capsule, entering 
the perinodal space and also the node. Cellular differentiation has proceeded 
apace but no lymph follicles are present as well as germinal centers. The 
typical cells now are the lymphocytes which appear in thickened masses 
at the periphery of the node extending into the perinodal space which seems 
to have no definite boundary. The earliest vascular relations are established 
by the advent of capillaries and arterioles from the surrounding tissues into 
the perinodal space and node. 
(3.) Drummond’s idea of the development of the lemolymph gland is 
that they are organs sui generis and develop in the parenchyma cells of the 
mesenchyme from or about a lymphatic plexus. He is opposed to the idea of 
their development from lymph nodes in spite of the fact that they closely 
resemble them in many points of structure for the following reasons: 
(A) Hemolymph nodes are not found in places where lymph nodes 
are found. 
(B) Some hemolymph nodes develop in the mesenchyme before 
lymph nodes. 
(C) The gap in structure between the two glands is too wide. 
27 The development in detail as worked out by the above investigator is 
as follows: 
In its early stage is is similar to the development of lymph nodes. Special 
cells in the mesenchymal mass become flattened and opposed to one another, 
forming a plexus of lymphatic vessels. Close to this plexus the first capil- 
laries with their erythrocytic and leucocytic content appear. The lymphocytes 
pass by diapedesis from the capillary wall of the blood vessel out to the 
embryonal mesenchyme and are caught in the meshes of the lymphatic plexus. 
Here they proliferate rapidly, forming a lymph nodule. At a later stage it 
was found that a capsule had been formed around the lymphoid mass by a 
thickening of the mesenchymal connective tissue. In the interior of this 
young gland a fiberous stroma formed a syncytial meshwork acting as a 
supporting structure. Beneath the capsule great numbers of erythrocytes and 
leucocytes then appeared and many red cells were apparent in the meshes 
between the lymphoid masses. 
It is easily seen that the final description given above is a picture of an 
adult hemolymph node. The blood capillaries, according to Drummond, were 
also developed from the mesenchyme and grew around the lymphoid mass 
after penetrating the fibrous capsule. 
(4.) Sabin’s statement of the development of hemolymph glands is that 
it is the same as that for lymph gland, except that in the former we have 
the lymphocytes surrounding a plexus of blood capillaries and a peripheral 
sinus of blood, while in the latter we have a plexus of lymphatics forming 
the basis of the development of a lymph gland. 
The above descriptions point to the fact that hemolymph glands are 
organs sui generis. Other investigators, however, claim that hemolymph nodes 
are formed from lymph nodes and vice versa, depending upon the physio- 
logical condition of the body; in disease, for example, when a great number 
of erythrocytes are being destroyed there is a change from lymph to hemo- 
lymph glands by an angiectatic dilation of the capillaries in the gland and a 
degeneration of the extranodal lymph vessels. In a change from a hemolymph 
to a lymph gland there is a very rapid proliferation of lymphocytes with a 
corresponding diminution in the size of the capillaries and obliteration of 
the blood sinuses. Meyer and Drummond have both given reasons for the 
disapproval of such a theory as the conversion of a mature lymph node into 
a hemolymph node and a summary of our data would indicate that the hemo- 
lymph organs arise sui generis. 
III. Function of Hemolymph Glands. 
Of the functions of hemolymph nodes the data at hand allows of a divi- 
sion into formative and destructive activities. The destructive functions of 
these structures are undoubtedly their outstanding feature and as such will 
be considered first. 
1. Destructive Functions 
Early in the course of their investigations research workers were struck 
with the presence in the blood sinuses of the hemolymph glands of large cells 
containing in their interior pale bodies which in many instances were stained 
with eosin. Two interpretations were possible of this phenomenon; the first 
was that the pale bodies contained in the interior of the peculiar large cells 
of the hemolymph organs were nothing more than red blood corpuscles in 
28 the process of formation; the second, just the opposite of the first, maintained 
that these large cells had taken up red blood corpuscles into their interior by 
phagocytosis, there to undergo disintegration. It is obvious that if the one 
view be carried to its logical end there will be assigned to hemolymph glands 
the function of producing red blood corpuscles, while if the second and 
opposite view be carried to its logical end there will be assigned to the hemo- 
lymph glands the function of the destruction of red blood cells. The second 
view, that the cells containing what seemed to some to be erythrocytes, are 
in reality only phagocytic cells, appears to be amply supported by one data 
and will be discussed under the present heading of “the destruction of red 
blood cells”; the first view will be taken up later under the head of the 
“formative functions of the hemolymph glands.” 
“Phagocytosis of the red blood corpuscles is the most striking feature 
of the hemolymph glands,” writes one investigator, “and has long been recog- 
nized as one of their more important functions.” Its extent varies greatly in 
individual cases of the same disease and in different glands from the same 
individual. However, all the various phases of the disintegration of the red 
blood corpuscles while contained in the phagocytic cells can be readily made 
out. In the interior of the phagocytes the injested erythrocytes may retain 
their normal appearance and staining reaction for some time; gradually, 
however, they swell slightly, and lose their property of staining with eosin, 
and finally appear like small vacuoles in the protoplasm of the phagocyte. 
These are commonly clustered around the nucleus, the peripheal part of the 
protoplasm being free from inclusions. Soon after, this pigment begins 
to appear in the peripheal part of the protoplasm in the form of minute 
granules of a golden yellow color. Whether the red corpuscles are completely 
digested or whether any “membrane” is extruded from these cells, it is 
difficult to say; such membranes have been described by Vincent and Harrison. 
The pigment thus deposited appears to run together into larger, irregular, 
homogeneous masses, which may almost entirely fill the protoplasm of the 
cell. Such masses of pigment, either contained in cells, or free, may become 
so abundant as almost to block up some of sinuses. 
The destruction of red blood cells as it is carried out by the hemolymph 
gland, seems to have some limiting factor and one may cautiously suggest 
that it is an intermittent or cyclical function as contrasted with a continually 
performed duty. An examination of several hemolymph glands which may 
be taken from the same source will well serve to bear out this point of view. 
For example, in one particular specimen one may find that the sinuses are 
filled with red blood cells, amongst which are a considerable number of 
leucocytes, but careful search may fail to reveal a single cell with red 
corpuscles in its protoplasm. In another gland phagocytic cells may be quite 
numerous in practically all of the sinuses and in practically all of which red 
blood corpuscles at about the same stage of disintegration can be seen. Again, 
in specimens where pigment is abundant, all of the pigment may be in the form 
of small granules or all of it may be in the form of large masses. These 
facts seem to indicate a cyclical function on the part of the individual glands. 
V hat starts this process is not known, but as suggested by Drummond, it 
may certainly be supposed that once started, the number of phagocytic cells 
in the sinuses increases rapidly and at the same time individual cells attack 
and engulf the red corpuscles which are abundantly present. By this double 
29 process of the increase of the number of phagocytic cells and increase in their 
individual size, the sinuses soon come to be completely blocked by them. 
Circulation through the sinuses is now at a standstill, because nearly all of the 
red blood corpuscles in the sinuses have been engulfed by the phagocytes. 
If this process takes place with some degree of rapidity one can understand 
how it is that we sometimes find a gland containing thousands of these cells in 
every section, every one of these containing apparently unaltered red blood 
corpuscles. Thus if we were to carry this mechanical explanation of the 
periodic phenomenon of phagocytosis in the hemolymph glands, as proposed 
by Drummond, only one step further, the logical conclusion could be arrived 
at, that the different phases in the disintegration of the red blood cells, having 
begun together, will run a parallel course. 
That the number of the hemolymph glands depends upon the rate of 
phagocytosis as it takes place in the individual glands is well illustrated by 
an examination of the number of hemolymph glands of the sheep, ox, dog, 
and cat. In the first two, the sheep and ox, the rate of destruction being 
minimum in the individual glands, there are thousands of these present, while, 
however, in the second two, dog and cat, where the rate of destruction in 
the individual glands is maximum, the glands are actually numbered by units. 
A little thought will undoubtedly give rise to the question that in the case of 
those animals where the rate of destruction is maximum will there not be a 
quick choking up of the sinuses with pigment and a consequent delayed 
circulation. It is of interest to note in this connection that another important 
difference between the glands of the dog and sheep is the remarkable develop- 
ment of the arterial supply of the former as compared with the latter. It 
is this very great development of the arterial system of the dog’s hemolymph 
nodes that accounts for the ability of these blood-destroying structures to 
continue their processes in spite of blood sinuses literally choked with thou- 
sands of phagocytic cells contains their prey. As a corollary to these ob- 
servations one may add the conclusion that the development of the arterial 
system of the hemolymph node in general is associated with the difficulty 
of maintaining the circulation through the gland. 
This question is now brought up by Lewis : is phagocytosis or intracellular 
destruction of erythrocytes the only means by which erythrocytes are de- 
stroyed? Is it not also possible that the phagocytes in addition to enclosing 
and digesting the red blood corpuscles, have also the power of secreting 
substances of a ferment nature which are capable of acting on erythrocytes 
or other blood corpuscles? According to Lewis, in certain glands of the 
Ungulata, in many of the sinuses, the blood corpuscles, more especially the 
erythrocytes show marked evidence of disintregation. The causes of the 
appearances of disintegration is by no means clear. The hypothesis of Lewis 
was. however, not put on any firmer basis by the work of Meek who experi- 
mented with gland fluid in an effort to see whether or not the gland cells 
or gland tissue secreted a substance with hemolytic powers. His experiments 
rather favored the view that the phagocytosis of erythrocytes was indepen- 
dent of any specific substance formed by the tissue proper. 
2. Formative Functions. 
A. To repeat what has already been said the first interpretation of the 
pale bodies contained in the large peculiar cells of the hemolymph nodes was 
that they were red blood corpuscles in the process of formation (so described 
30 by Robertson, Clarkson, and Gutig.) If such is the case, then the hemolymph 
nodes can certainly be said to be a source of red blood cells just as the red 
bone marrow is. However, most of the investigators of the problem agree 
that under normal conditions the hemolymph nodes do not show such a func- 
tion as the formation of erythrocytes. Warthin does make the statement 
that while he has seen nucleated red blood cells under pathological conditions 
he has never seen any in normal nodes. 
Though time has abandoned the old view of the origin of erythrocytes 
from what are now definitely known to be phagocytic cells, one investigator, 
namely, Meek, still holds on to the idea of the formation of red blood cells 
in the hemolymph gland. His proof of this formation is however not based 
on an origin from the pale eosin staining bodies of the phagocytes, but upon 
observations which he made of such glands in the pig and human in which 
he claims to have seen and pictures nucleated red blood cells. The unique- 
ness of his work and his solitary position with reference to this function of 
the hemolymph glands demands our close attention. 
“Of especial interest,” says Meek, “are certain islets of cells which 
occur in the midst of the blood in the sinuses. They are sharply defined 
from the surrounding red blood corpuscles, and one such focus will contain 
perhaps 50 closely packed normoblasts, another a lump of myelocytes, neutro- 
philic or eosinophilic in granulation, while yet others are made up of aggre- 
gations of polymorphnuclear cells. Mitotic figures may be seen in the cells 
of these islets. Another cell of interest to be seen in the sinuses, though only 
occasionally, is a large cell closely resembling the megakaryocyte of bone 
marrow.” The presence of these nucleated red blood cells would seem to 
suggest that a part at least of the function of these glands in the pig, where 
a large number of them are easily seen, is connected with the formation of 
red blood cells. However, the same author, in the same article, states that 
glands examined by him taken from patients dying with signs of grave 
anemia very rarely showed the occurrence of nucleated red blood cells. Again 
no instance was met with in which nucleated red blood cells were found in 
appreciable numbers in the hemolymph glands without the presence of these 
cells in considerable number in the bone marrow and blood. These findings 
somewhat confirm the belief that the hemolymph glands may assist or even 
replace the bone marrow (though the latter is hardly possible) insofar as 
this particular function is concerned. The conclusion Meek draws from his 
experiments is that histological evidences of the hemopoietc iunction of the 
hemolymph glands are only to be seen in man in comparatively rare instances, 
and that when exercised the reaction is just as a rule secondary to a similar 
action of the bone marrow. Just as Meek stands alone in his observation 
of nucleated red blood cells being present in the sinuses of the hemolymph 
nodes so does Retterer, who holds still another view of the formation of red 
blood cells within the glands, namely, that they arise from the lymphocytes 
by a hemoglobin transformation of the nucleus, remain unconfirmed in his 
work. Thus, according to Meek, the production of nucleated red blood cells 
in the glands of the pig undoubtedly takes place as shown by their presence 
under the microscope and a similar production in human hemolymph glands 
is not so well marked but is rather dependent on the reaction of the red bone 
marrow in its formation of red blood cells. 
B. The constant presence of lymphoid tissue more or less abundant, the 
usual presence of germ centers in which cell division is actively going on, 
31 indicate that the hemolymph glands serve as active centers for the manu- 
facture of leucocytes. The arrangement of the blood sinuses around the 
lymphoid tissue is extremely favorable for the rapid escape of the leucocytes 
into the general circulation. 
C. Polykaryocytes and some megakaryocytes are found in the nodes. 
These, to be sure, could not easily leave the node or be transported there 
because their great size and must hence have arisen within the node itself 
or else have been transformed there. 
D. An increase in the number of endothelial cells is one of the most 
constant morbid changes seen in hemolymph glands. These cells are familiar 
as the main phayocytes of lymphoid tissue and play a prominent part in the 
destruction of red blood corpuscles. Their phagocytic activity is often very 
great and an individual cell may be seen to contain 20-30 red blood corpuscles. 
E. The polymorphnuclears and neutrophile myelocytes seen in the hemo- 
lymph glands by Meek were confined almost entirely to the sinuses, and 
the appearances suggested that the sinuses were probably acting as a site 
for their production or multiplication. 
F. Of especial interest are the presence in the glands of numerous 
cells containing coarse granules strongly stainable with eosin. In the majority 
of these cells these granules are closely packed; in other cells they are large 
and more irregular fragments; in a very few an entire erythrocyte is included. 
In some of the sinuses eosinophile cells are seen in contact with damaged 
erythrocytes or surrounded by debris already described as consisting of eosino- 
phile granules. In those cells in which few granules are found, the ring of 
protoplasm surrounding the nucleus is small, and the latter is almost always 
singular, such cells approach in size and appearance the well known lym- 
phocyte. The question may now be asked: Do not these appearances sug- 
gest the formation of eosinophile leucocytes from the products of disintrega- 
tion of the red blood cells? It at first sight appears unlikely that a small 
uninucleated cell should develop into a far larger one with not a round, but a 
polymorph nucleus. The injection of numerous particles, however, might be 
a potent factor both in the distension of the cell wall and in the distension 
of the nucleus. 
3. Compensation for Spleen. 
While it is not the purpose of this paper to give a complete discussion of 
the function of the spleen we thought it would be useful, since this organ is 
often classed as one of the hemolymph glands, to draw a comparison between 
the two, and particularly to see what changes the hemolymph nodes undergo 
in cases of spleenectony or absence of the spleen. Thus, the conclusion 
might be reached that the hemolymph glands and spleen are closely allied 
and have the same main activities in the body, if it can be shown that the 
hemolymph organs can replace the spleen in the case of the latter’s absence. 
Due to the general similarity in structure of the hemolymph glands and 
spleen, their common function of hematolysis and the occurrence of transi- 
tion forms resembling accessory spleens, but chiefly due to the autopsy find- 
ings in a case of spleenic anemia in which there was throughout the mesentery 
fat a new formation of hemolymph nodes resembling spleenic tissue, Scott 
Warthin, the author of the series of experiments upon which this part of 
our article is based, put forth the hypothesis that hemolymph nodes under 
certain pathological conditions may compensate for the spleen. 
32 Spleenectomy was carefully performed on eight animals; six sheep and 
two goats were used in these experiments; mechanical difficulties leading to 
injuries were avoided as much as possible during the operations and fairly 
normal results were obtained. All of the animals recovered soon after 
spleenectomy and were carefully examined at stated intervals of one week, 
two weeks, one month, two months, and five months, with particular refer- 
ences to the changes in the hemolymph nodes which they possessed. The 
results are given in the following table: 
Time 
Phayocytic Activity 
Proliferation Lym- 
New 
Formation 
of 
phoid Tissue 
Hemolymph Nodes 
1 
Week 
Increase; shown by 
Beginning of Proli- 
increase in phayo- 
cytes and number of 
cells containing eosi- 
nophiles granules. 
feration. 
2 
Week 
Greatly increased; 
Active proliferation; 
shown by same facts 
evident by numerous 
as 1, only in greater 
mitoses present 
amount. 
throughout hemolymph 
node. 
1 
Month 
More marked in- 
More marked proli- 
New 
formation. 
crease. 
feration. 
HemolyAph node 
in 
adip. 
tissue. 
2 
Months 
Increased Hemoly- 
Advanced hyperplasia 
New 
formation 
in 
sis : Marked eosino- 
of all lymphoid struc- 
adip. 
tissue. 
uhilia. 
tures. 
5 
Months 
Marked Act: Eosi- 
Great hyperplasia. 
New 
formation 
in 
nophilia. 
adip. 
tissue. 
It is evident from the preceding table that spleenectomy in the sheep is 
followed during the first five months by a compensating hyperplasia of pre- 
existing lymphoid tissues, transformation of hemolymph nodes into ordinary 
lymphatic glands, and a new formation of hemolymph nodes in the adipose 
tissues. No evidence of regeneration or new formation of spleenic tissue 
was found; likewise no evidence of formation of red blood cells in the 
hemolvmphatic glands after spleenectomy was found. Insofar as the ques- 
tion of compensation for spleenic function is concerned, the results of the 
above experiments would bring out the fact that destruction of red blood 
corpuscles and leucocyte formation are the two functions which are taken 
up to an increased degree by the hemolymph nodes and lymph glands after 
spleenectomy. That the spleenic function is not entirely compensated for is 
shown by the disturbed equilibrium of the blood in the excess of hemolysis 
over blood formation. According to Warthin, this might be explained by 
the hyopthesis that there is some hemolytic agent found in the body which 
is normally taken care of by the spleen or the spleen has some influence in 
the new formation of hemoglobin. 
Several other facts brought forward by S. Warthin are also of some 
interest. The new formation of hemolymph nodes along the hilum or along 
the vessels of the peripheal glands whose medullary portion showed pigmen- 
33 tation, might be taken, according to Scott Warthin, in support of the view 
that the pigment is carried from the neighboring hemolymph node to the 
lymphatic glands through the lymphatics. The hemolymph nodes would hence 
be acting as hemolytic organs passing their products of blood destruction on 
to the lymphatic glands for further elaboration. . The presence after spleen- 
ectomy of a great number of eosinophiles in those glands of the experimental 
animals showing great destruction of red cells seems to point to some rela- 
tionship between these cells and the destruction of the latter; one would not 
be stretching it very far to come to the already spoken of conclusion that 
eosinophiles arise directly from the disintregation products of the red blood 
cells being taken up by the small lymphocytic cell. 
As far as could be determined, no definite function as regards the 
general immunity of the body and the origin of antibodies was assigned by 
investigators, as a result of their experiments, to the hemolymph nodes. 
However, several of these men have hinted in their papers that these glands 
might play an important part in the production of immunity and the pro- 
tection of the body through the formation of antibodies. When one con- 
siders the close resemblance of the hemolymph nodes to the spleen, which 
organ is fairly definitely established as a center of origin for antibodies, 
or at least of an anti-hemolytic agent; also when one considers the close 
connection of the cellular make-up of the hemolymph glands with that of 
the blood, the hyopthesis that they may produce anti-bodies does not seem 
so far fetched. 
BIBLIOGRAPHY 
Clarkson: Cited by Meyer, A. W., A. J. A., vol 21. 
Dayton, Hughes: Amer. Jour. Med. Sc., vol. 127, 1904. 
Drummond, W. B.: Jour. Anat. & Phys., London, vol. 34. 
Gutis: Cited by Meyer, A. W., A. J. A., vol 21. 
Lewis, Th.: Jour. Anat. & Phys., London, vol. 38. 
Meek, W. O.: Quart. Jour, of Med. Oxford, vol. 3. 
Meyer, A. W.: Amer. Jour. Anat., vol. 21, 1917. 
Retterer: Cited by Meyer, A. W., A. J. A., vol. 21. 
Sabin, F.: Cited by Meyer, A. W., A. J. A., vol. 21. 
Warthin, A. S.: Jour. Med Res., 1901, vol. 6; 1902, vol. 7. Trans. Chicago Path. 
Soc., vol. 5. Proc. Path. Soc., Philadelphia, vol. 6. 
34 SENESCENCE AND REJUVENESCENCE 
T is proposed in this paper to give a brief outline of some of the aspects 
of the problem of Senescence and Rejuvenescence. It has been necessary 
1 to leave out considerable data and in going over the available material it 
seemed possible to bring out the main points of the problem while omitting 
the work on plants and that on the specific diseases of old age. The dis- 
cussion has therefore been limited to four main topics, histological and morpho- 
logical changes in senescence and rejuvenescence, physiological changes; some 
of the present day theories of senescence and rejuvenescence, and some of the 
experiments. 
The problem of senescence and rejuvenescence is essentially one of living 
matter, that is of the living organism. But what is the organism? There 
are many theories, the neo-vitalistic, the corpuscular, the chemical, the physio- 
chemical and the colloidal substratum of the organism, are a few of them. 
C. M. Child defines the organism as: “A specific complex of the dynamic 
changes occurring in a specific colloid substratum which is itself a product 
of such changes and which influences their course and character and is altered 
by them.” He maintains that the differentiation and dedifferentiation of the 
organism is the basis of senescence and rejuvenescence. Senescence is, there- 
fore, according to his definition, “a decrease in the rate of dynamic processes 
conditioned by the accumulation, differentiation and other associated changes 
of the material of the colloid substratum, and rejuvenescence is an increase in 
the rate of dynamic processes conditioned by the changes in the colloid sub- 
stratum in reduction and dedifferentiation.” 
These definitions give us some idea of what is meant by senescence, but 
to show what old age really consists of we must consider the changes, histo- 
logical, morphological and physiological associated with it. 
“Old age,” as a term usually brings to our minds a definite picture. We 
are familiar with the shrunken stature, the shuffling gait, the wrinkled face 
and the slow mind of the old man of the human species. The decrease in 
stature is always very marked and is due largely to the bony fusion of the 
spinal column. It was estimated in some German statistics that though at 
thirty the average height for man was 174 centimeters, at seventy the average 
was only 161. It is well known also that the long bones of the old break 
more easily than do those of the young, due to a smaller amount of spongy 
or cancellous bone and a greater amount of solid bone. This increase of bone 
tissue is seen everywhere, especially in the cartilage of the ribs. It is 
progress of a kind, but progress carried to excess. The shuffling gait is 
largely explained histologically by an actual decrease in the number of muscle 
fibres in a given muscle. They apparently wear out. The wrinkled appear- 
ance of the skin is merely indicative of what is going on within, and this 
process is most generally given the specific name of senile atrophy. 
This phenomenon, if such it may be called, of senile atrophy, concerns 
practically all the more highly specialized organs and to some extent all the 
tissues in the body. It is more noticeable in the higher forms of life which 
35 have more highly specialized tissues. The changes of senile atrophy consist 
essentially of a decrease in the size of the cell and more or less degeneration. 
It must not be assumed that all tissues are simultaneously affected by senile 
atrophy for it is obvious if this condition exists in a certain proportion of the 
tissues, death will occur. This atrophy of the tissues is undoubtedly associated 
with the decrease in the rate of metabolism, which will be discussed under 
the physiological changes of senescence. This shrinkage in old age would 
be much more marked than it is, were it not, that as the more highly differen- 
tiated tissues give way to senile atrophy, they are, at least partially, replaced 
by connective tissue. As Wooton puts it, “Histologically death from old age 
is the victory of connective tissue over the more specialized tissues.” 
One of the places where this senile atrophy has been most observed is 
in the brain and nerve cells, and this relates itself, of course, to the enfeebled 
mentalities of the aged which was noted in the beginning as one of the most 
obvious outward signs of age. Perhaps the most distinguished piece of work in 
this line was done a good many years ago by Hodges on the changes in the 
ganglion cells from birth to senile death in many and honey bees. In man, 
he made careful, though not exhaustive, examinations of two sets of gang- 
lion cells, one set from an old man dying from senile decay at the age of 
ninety-two and the other from a new born infant. In the former, the cyto- 
plasm was full of pigment, the nucleus shrunken and irregular and the nucleo- 
lus poor staining, whereas in the young ganglionic cells the cytoplasm had 
little pigment, the nucleus was round, and the nucleolus deep staining. His 
experiments on the honey bees, carried on at the same time, afforded a chance 
for more control and for a larger number of subjects. The results tallied 
very well with his observations on the human. In the old, the cytoplasm 
was full of large granules, many vacuoles, and the nuclei were shrunken, 
whereas in the young the cytoplasm was evenly granular and the nuclei large 
and clear. These observations of Hodges show why it is so often noticed 
that the brain of the old is actually shrunken. In persons of a height of 
175 cms. of male sex of twenty to forty years the brain weights 1.409 grams, 
from 41 to 70 years it has shrunken to 1,363, and from 71 to 90 years it has 
shrunken to 1,330 gms., on the average. The shrinkage begins soon after the 
attainment of maturity and continues steadily to the end of life. 
Another important histological change, due to senile atrophy, is the change 
in the arterial system. The arterial system invariably shows changes in the 
direction of decreased elasticity and contractility of the artery walls resulting 
in arterio-sclerosis. (We will see later that all the authors do not feel that 
arterio-sclerosis is as fundamental a fact of old age as it was once believed 
to be.) Due to the changes in the arterial system, the heart often hyper- 
trophies instead of atrophying, but this is generally believed to be a functional 
reaction due to the increased work of the heart, necessary because of changes 
in the arterial system. 
Not all the changes of old age are morphological and histological how- 
ever. Some can only be classed as physiological. The striking physiological 
fact is the decrease in the rate of metabolism. Aub and De Bois, to cite 
merely one of the experiments on the basal metabolism of the aged, carried 
on a careful series of experiments in 1917 on six old men between the ages 
of seventy-seven and eighty-three, with the calorimeter apparatus. Their 
average basal heat production was 35.1 calories per square meter per hour. 
This is twelve per cent lower than the average for men between the ages 
36 of twenty and fifty. Just what this lowered rate of metabolism may mean is 
stated by Wooton: “Senile decay is auto-failure, it connotes metabolic im- 
pairment and consequent poisoning.” Defective oxygenation and inability to 
carry off waste products go hand in hand with senile decay. What lies back 
of this decrease in the rate of metabolism is not very clear. Bue we are lead 
to suspect some changes in the thyroid which governs metabolism, and at the 
present there is a good deal of discussion on this point. Summarizing then 
the changes seen in age, it might be said that the most important morpho- 
logical and histological change was senile atrophy of the specialized tissues 
with an increase in the amount of connective tissue, and on the physiological 
side, a decrease in the rate of basal metabolism. 
Various workers observing these changes of old age which we have put 
forth above have stressed one phase or another and have evolved various 
theories accordingly. Minot, on the one hand, sees in senescence and death 
merely the natural end of cytomorphosis ; while on the other hand, according 
to the medical view, senescence is almost a pathological condition. The 
changes which particularly interested Minot are the histological changes of 
the cells. “Age,” he says, “is the result of cumulative cytomorphosis.” Sen- 
escence depends on the increase of cytoplasm in proportion to the size of the 
nucleus, together with its increased differentiation. The power of rejuvena- 
tion is lost when the nucleus becomes small in proportion to the amount of 
cytoplasm. There is no doubt that this relation is born out in ‘ observations 
on “young” and “old” cells, but as to whe'her cytomorphosis tells the whole 
story or whether it is merely an expression of the other factors working to 
produce senescence it is hard to say. 
More closely related to the physiological changes but taking in only a 
very narrow field are Metchinokiff’s theories. To him senescence was a result 
of auto poisoning produced by the bacteria of the large intestine. This is 
mentioned because of the wide publicity his theories have received but it 
does not cover all the ground. 
There are those however, who in recent years have seen in the endocrine 
glands the answer to the problem. We have noted before that the thyroid 
and other endocrine organs, secondarily, may have a decided effect on the rate 
of metabolism. Lorand has pointed out that at a certain age the different 
ductless glands show important changes, notably an increase of connective 
tissue with consequent degeneration of the secreting tissue. Seventy thyroid 
glands which he examined in aged subjects showed marked degeneration. It 
is also seen that myxodemia and old age have certain points in common, which 
might lead to the conclusion that both were due to thyroid deficiency. So 
firmly do some believe this that they advocate the administering of thyroid 
extract in old age. These workers have changed the expression “A man is 
as old as his arteries” to read, “A man is as old as his endocrine glands.” 
This theory is upheld by G. Stanley Hall in his recent publication on “Sen- 
escence.” That all are not ready to accept this view is shown by an article, 
also recently published, by Thompson and Todd in the Lancet, in which they 
say that thyroid insufficiency is not characteristic of old age and that the 
simple wearing out of the mechanical factors of the organism from use is 
the more direct explanation. 
It is regrettable as we review these theories to see that there is no one 
theory which by any means adequately takes into account all the changes 
of old age. The remedy will come we believe by the application of some 
37 of the more carefully controlled experimental work on lower animals to the 
changes seen in man. For these reasons, bearing in mind the changes seen 
in man, some of the more recent experimental work as it applies to senescence 
and rejuvenescence will be considered. 
Dealing with the lower animals, C. M. Child carried out a series of 
experiments on Planaria to determine the age differences in susceptibility. 
Using Planaria dorotocephala, Planaria maculata, and Planaria velata he 
concluded that there was a general age difference in the susceptibility of these 
animals to cyanides and narcotics. The younger animals showed the highest 
susceptibility and this susceptibility decreased with advancing development. 
In other words, the rate of metabolism is highest in the young animals ot 
this species and decreases with advancing age. A similar decrease in the 
rate of metabolism with increase in age was pointed out in man. 
Calkins in his experiments on Protozoa in 1904 used Paramoecia, which 
he cultivated in the laboratory. The Paramoecia, which were not allowed 
to conjugate, were observed to pass through cycles of vigor and depression, 
each cycle being of three months duration. During the depression period, 
division always slowed up and more accumulation of waste material occurred, 
different in kind in the later periods than in the earlier. This he maintained 
to be due to different physical conditions and to a weakening of different 
functions. 
Although the conditions of the experiment were believed to be practically 
normal, death occurred after twenty-nine months, apparently from exhaustion, 
for at death there were no morphological signs of senility. The signs of old 
age seemed from this experiment to be functional, the slowing up of division, 
and the accumulation of more waste material in the later periods of de- 
pression, and old age seemed to be a natural condition of living protoplasm. 
Other experiments on Paramoecia were undertaken by Woodruff, who 
has maintained a strain of these animals through two thousand generations. 
He observed that, “Their life history was characterized by a general decline 
of the division potent ending in death when the organisms were subjected to 
a constant environment but that the life history might be prolonged by the 
use of certain stimuli.’’ He found, as did Calkins, that there was a periodic 
variation in the rate of multiplication, there being cycles of rise and fall 
of fission rate which ended in extinction unless conjugation occurred or there 
was a change in environment. No conjugation was allowed but, carrying 
on the experiment, frequent change in environment was made and the culture 
showed after forty-one months and two thousand generations that, “when sub- 
jeceted to suitable culture condition it, that is undifferentiated tissue, has the 
power of unlimited reproduction by division without conjugation or artificial 
stimuli.” 
Dr. Carrel carried on a series of experiments at the Rockefeller Insti- 
tute in which he proposed to determine two things: first, whether a definite 
relation existed between the rate of multiplication of fibroblasts cultivated in 
plasma and the age of the animal from which the plasma was taken; and 
second, whether any modifications brought about by age in the action of the 
plasma on the fibroblasts were due to the disappearance of an accelerating 
factor or the production of an inhibiting factor in the plasma. 
Using the technique employed in the cultivation of tissue in vitro and 
plasma from chickens, he tried a variety of types and ages of plasma. Ii 
was always found that the fibroblast rate of growth was greater in the 
38 younger tissue. There was no doubt that the rate of multiplication of the 
fibroblast and the duration of their life in vitro varied in inverse ratio to 
the age of the animals from which the plasma was taken. 
Various concentrations of the same plasma were used to find out whether 
it was the decrease in an accelerating factor or the increase in an inhibiting 
factor which caused the decrease in the growth in the fibroblasts cultivated in 
plasma of older chickens, and it was found that the serum of the three-year- 
old chick contained a factor inhibiting the growth of fibroblasts. At no 
age was high concentration found to be good, showing that there never was 
an accelerating factor present. 
In still other experiments he fousd that by transfusing blood from a 
young dog to an old one a marked difference was soon observed in the physical 
condition of the old dog. He also tried a method of washing the blood to 
see if this inhibiting factor, if such it was, could be removed, and found 
that old dogs, some of whose blood had been removed, washed in a special 
manner, and reinjected showed distinct signs of rejuvenescence. These 
experiments have not as yet been completed and hence no conclusion can be 
drawn from them but they seem to point to the fact that senescence is due 
to the presence in the blood of a factor which inhibits growth. 
With the exception of these experiments which are still incomplete, no 
work seems to have been done on rejuvenescence in higher animals. It ap- 
pears that with high differentiation the power of rejuvenescence is lost to a 
greater or less degree, but in the lower animals in which there is a large 
amount of undifferentiated tissue this phenomena has been demonstrated. 
Child in his experiments on Planaria produced new animals by recon- 
stitution, these animals resembling a young animal in their morphological 
features and being capable of growth and development. He accomplished this 
by cutting pieces from Planaria; new embryonic tissue forming at the cut 
surfaces which gradually became old after its formation, while the other 
parts of the piece became young by reconstitution and reorganization until a 
dynamic equilibrium was established in the rate of metabolism in the different 
parts. He found that the rate of metabolism was higher in the cut pieces 
than in the same region of the body in an uninjured animal in the same 
physiological condition. 
He concluded from these observations that, “The process of reconstruction 
brings about in some way a greater or less degree of rejuvenescence in these 
relatively simple animals and the degree of rejuvenescence is, in general, 
proportional to the degree of reorganization in the process of reconstitution of 
the piece as a whole.” 
By successive reconstitutions, alternating with feeding and growth, he 
brought the animals back to essentially the same stage in the age cycle in 
each successive generation, and by successive reconstitutions, without feeding 
and growth, the animals were made progressively younger physiologically in 
each generation until further reconstitution became impossible. 
To sum up then, it seems that the problem of senescence and rejuven- 
escence goes back fundamentally to histological and physiological facts. The 
one fact common to all life is the physico-chemical relationship, for the 
change in the rate of metabolism observed from the experiments on lower 
animals is also seen in man. On the histological side, however, it has been 
pointed out that there is no such correlation between senescence in the lower 
and higher forms of life due perhaps to the greater differentiation of tissues 
39 in the latter. Yet it is in the histological field that the most successful ex- 
perimental work has been done on rejuvenescence, while we must look to the 
future for the solution of this problem in physiological terms. 
BIBLIOGRAPHY 
Calkins, G. N.: “Studies in Life Histories of Protozoa,” “Death of Species.” Jour- 
nal of Experimental Zoology, Vol. 1, 1904. 
Carrel, A.: Journal of Exp. Medicine, 1 g 13 xviii. 
Child, C. M.: “Senescence and Rejuvenescence.” 
DuBois: “Basal Metabolism of Old Men,” Arch. lnt. Med., May, 1917. 
Hall, G. Stanley: “Senescence.” 
Hodges, C. F.: “Changes in Ganglion cells from birth to senile death.” “Observa- 
tions on Man and Honey Bees.” Journal of Physiology. Vol. 17, 1894-95. 
Korschelt, E.: “Lebensdauer Altern und Tod.” 
Lorar.d, A.: “Old Age Deferred.” 
Loeb, J., and Northrup, J. H.: Journal Bio. Chem., 1917, xxxii 103. 
Minot, C. S.: “The Problem of Age.” “Growth and Death.” 
Scott: “Endocrines in Treatment of Premature Old Age.” N. Y. Med. Journal, 
115:431-433, April 15, 1922. 
Thompson and Todd: “Senescence and Senility.” Lancet, 1:874-877. 
Taylor: “Premature Old Age.” Med. Rec., 92:758, Nov. 13, 1917. 
Woodruff: On Paramoecia. “Further Studies on Life Cycle of Paramoecia.” Biolog. 
Bull., Sept., 1909. 
Wooton: “Metabolism of Senile Decay.” Dublin Journal Med., July, 1916. “Con- 
servation of Youth.” Idem., Aug., 1913. 
Wright: “Prolongation of Life,” Canadian Med. Journal, June, 1920. 
40 THE GROWTH OF TISSUES IN VITRO 
WE owe to Harrison the first successful culture of tissues in vitro. In 
1907 he was working on the problem of the origin of nerve fibres. Do 
nerve fibres grow out from ganglia, or do they differentiate from pro- 
toplasmic bridges ? Harrison solved this long-standing embryological problem. 
But more significant than the solution of this problem was the introduction 
by Harrison of a new biological method. The reason why it had been pre- 
viously impossible to come to a definite decision on the question of the origin 
of nerve fibres was that it had been impossible to separate the ganglia from 
the protoplasmic bridges. Harrison succeeded in growing isolated ganglia in 
vitro, that is, outside the organism. From a frog embryo, he obtained ganglia 
free from the surrounding tissue, and placed them in a drop of lymph from 
an adult frog, in a manner to be described later. In this lymph drop, he was 
able to observe nerve fibres growing out from the ganglia. Was this, however, 
a normal process? Do cells in vitro differentiate as they normally do in 
vivo, that is, in the organism? To determine this, cells whose normal dif- 
ferentiation was already definitely known, were put in lymph drops and 
observed. It was found that muscle plates differentiate into muscle fibres with 
cross striations, and that epidermis cells took on a cuticula and functioning 
cilia. There was, therefore, no reason to suppose that the outgrowth of nerve 
fibres from ganglia was an abnormality, due to in vitro conditions. On the 
contrary, this new technique enabled Harrison to conclusively solve the problem 
of the normal origin of nerve fibres. 
Only a few years later another important biological problem was attached 
by the in vitro method. Can heart muscle contract without nervous stimula- 
tion? The weight of evidence in this much disputed question indicated that 
the rhythmical contraction of the heart is possible without nervous stimula- 
tion. Burrows contributed further evidence in favor of the myogenic theory. 
He isolated in vitro a small piece of heart muscle and observed that though 
unquestionably free from all nerve fibres, it beat with a perfectly normal 
rhythm, and with a rate and force similar to heart pulsation in the embryo. 
The technique which Harrison and Burrows used was this: A drop of 
plasma (a culture medium which Burrows substituted for the lymph used 
by Harrison) is put on a cover glass, and on this drop is placed a minute 
fragment of the tissue. The cover glass is then inverted over a hollow slide 
so that the drop is suspended from the cover glass in the hollow. The actual 
technique is almost infinitely complex. The following are only some of the 
more important factors which must be considered. First: The tissue frag- 
ment must be very small, in general but a few mms. For every particular 
case, there is an optimum size, and if the fragment is the least bit larger or 
smaller than this the results are decidedly inferior, in fact, no growth at all 
may occur. Similarly the size of the drop is important, and there is in addi- 
tion an optimum relation between the size of the tissue fragment and the 
sizes of the drop. Harrison used lymph as his culture medium, but Burrows 
41 and Carrel found plasma more convenient. Furthermore, they found 
that plasma coming from the same species as the tissue fragment, 
that is, homogenous plasma gave better results than heterogenous plasma. 
The next improvement was the use of plasma from young rather than from 
ac-ul: animals. In all cases, after several days, death occurred because of 
the accumulation of metabolic products and the exhaustion of the food supply. 
To remedy this, cultures were removed from time to time to a fresh medium, 
after having been washed free from metabolic products with Ringer’s solution. 
Even so, cultures did not survive more than several generations. By the 
addition of embryonic tissue juice to the medium, however, the life of tissue 
cultures could be prolonged practically indefinitely. Carrel, at the Rockefeller 
Institute, now has a strain of fibroblasts which has been growing in vitro 
for over ten years. The cells of this old strain have not changed their mor- 
phological characteristics since the first culture, and they proliferate at least 
as rapidly as the original fibroblasts. The plasma in the hanging drop soon 
clots. This is essential for some solid framework is needed for cell growth. 
If no clot forms, as in the case of amphibian plasma, where clotting is 
greatly delayed, there is no growth and Harrison proved that the fibrin func- 
tioned only as a framework by substituting for fibrin silk threads and spider 
webs. The protoplasmic bridges which were mentioned in the problem of the 
origin of nerve fibres, probably served as such a mechanical support for the 
nerve fibres as they grow out from the ganglia. We have described only a 
few of the necessary details of the technique. The most important precaution 
is to keep the culture free from bacterial infection. There are, however, a 
great many detailed precautions, the neglect of any one of which will result 
in the death of the cells. For instance, the exposure of thyroid tissue to the 
drying action of ordinary air for more than ten seconds kills the tissue. 
Indeed, according to Carrel, the entire procedure is best carried out in the 
humid atmosphere of the operating room. By means of this technique, it has 
been possible to grow in vitro almost all kinds of cells and tissue, leucocytes, 
epithelium, muscle, connective tissue, lymphoid tissue, cartilage, nervous tissue, 
tissue from kidney, heart, thyroid, etc. 
For the present, then, so much for technique. What are the advantages 
of this method in studying biological problems ? The value of studying 
isolated parts of the organism has long been recognized. In physiology, many 
discoveries have been made by experimenting on isolated organs, and the 
so called egg shakers of the school of Roux have advanced embryology by 
separating various parts of the embryo and observing the development of the 
separated parts. Even the idea of isolating tissues, and growing them in vitro, 
is by no means new. Leo Leob tried growing tissues in test tubes. In addition 
to the fact that he failed to get continued growth, there was also the difficulty 
of not being able to observe the tissues while growing. Harrison overcame 
this difficulty by adopting the hanging drop method of bacteriology. By this 
method, it is possible to observe the growth of isolated tissues in an environ- 
ment which can be varied and controlled. The isolation of pure strains of 
tissues has been exceedingly difficult. So far there have been grown pure 
strains of connective tissue, epithelium, cartilage and leucocytes. Of these, all 
except the connective tissue were obtained only within the past year. Hence, 
it is probable that more pure strains will soon be obtained. Many of the 
early errors and uncertainties in work with tissue cultures can now be traced 
to the fact that the cultures were not pure. For example, a mass of ap- 
42 parently sound experimental work was done on the transformation of epithelial 
into connective tissue. £t now appears that this connective tissue had its 
origin in connective tissue already present in the culture. Had a pure strain 
of epithelium been used, this objection could not have been raised. 
The method of tissue cultures has been mainly criticized on the ground 
that in vitro conditions are different from in vivo conditions, and that there- 
fore it cannot be assumed that the processes observed in vitro are necessarily 
those whick go on in the organism. As Harrison has said, this same criticism 
might have been brought against the early science of chemistry by naturalists 
who claimed that chemists should concern themselves with descriptiive miner- 
ology rather than with abnormal compounds. The fact that conditions are 
abnormal does not mean that nothing can be learned from studying what 
occurs under the abnormal conditions. What can be learned is the reactions 
of tissues and cells to various definite environments? The total behavior of 
an organism is the complex result of the actions and interactions of the in- 
dividual parts. In vitro, we are able to study the action of a part free from 
the complicating effects upon it of the rest of the organism. By this sort of 
analysis we can hope to build up a general science of a behavior of tissues and 
cells. Occasionally, by comparison with what is known to occur in the or- 
ganism, one can find out whether a particular process observed in vitro is 
abnormal or not. For instance, as we have already said. Harrison observed 
that muscle plates happened to differentiate in vitro just as they were pre- 
viously known to differentiate in the embryo. The fact that we cannot study 
in vitro the complex inter-actions which take place in the organism is no 
reason for avoiding the method of tissue cultures. The fetish of the organism 
as a whole, as Harrison put it, must not prevent experimentation in biology. 
We now come to the results gained by the method of tissue cultures. 
These results often have very little connection with each other, for, after all, 
we are discussing a method rather than a problem. Investigators with all 
sorts of problems have used this metod of experimentation, and their results 
usually have no more in common than their problems. We shall use these 
varied results to illustrate the general advantages and possibilities of the 
method we are discussing. The advantages are briefly these: Isolation of 
parts, control of medium and the possibility of close and continued observa- 
tion under the controlled conditions. 
One type of problem studied was that of morphogenesis. We have already 
shown how Harrison demonstrated the origin of nerve fibres. In studying the 
genetic interrelationships of leucocytes and other cells, Maximoff and Carrel 
used the in vitro method with great success. Maximoff observed in vitro the 
transformation of lymphocytes into granular acidophil leucocytes. He could 
observe the steps of the transformation, a myelocyte, the normal ancestor of 
granular leucocytes being one of the definite stages. He also' found that some 
lymphocytes and reticular cells became large mononuclears, and that some 
reticular cells became lymphocytes. More recently, Carrel found that some 
large mononuclears from a pure culture differentiated into normal fibroblasts 
(i. e., into primitive, connective tissue cells). This gave support to the old 
idea of Renaut that connective tissue is derived from lymphocytes. These 
experiments do not conclusively show that the transformations observed take 
place in the organism, but they do indicate certain intimate genetic relation- 
ships among various lymphocytes, granulocytes, large mononuclears, cells of 
43 reticular tissue and fibroblasts, and they show the possibility of certain trans- 
formations taking place in the organism. , 
We shall now present several morphogenetic experiments which illustrate 
the convenience and reliability of the in vitro method. Richard Goldschmidt 
observed the whole course of spermatogenesis in vitro. The process of sperm- 
atogenesis, which takes weeks in the organism, can, by warming, be hastened 
in vitro so that it is completed in one day. McWhorter and Whipple were 
able to observe the continuous development of a blastoderm in vitro from a 
three to an eighteen somite stage. They found, as did Goldschmidt, that what 
they observed in vitro was, in all essentials, in agreement with previous 
knowledge. But certain things could be studied in vitro that either were 
difficult or impossible to study by the ordinary technique. For instance, they 
observed that on the collapse of a blood vessel the endothelium went back to 
undifferentiated mesenchyme. They also observed the formation of new blood 
channels, the first heart beat, and its immediate consequences. Since then, 
Sabin has used the same method to study the early development of the vascular 
system. These are only some of the applications of the in vitro method to the 
study of morphogenesis. 
The most frequent application of the method has been in studies on the 
effects of different environments on the form and growth of cells. The form 
of the cell and the structure of the cell mass depend not only upon the tissue 
from which the cells were taken, but also upon the mechanical conditions of 
the medium—such as the viscosity of the drop, and the density of the fibrin net- 
work. A striking example of the effect of a medium on the form of the cell 
is seen in the change in the form of certain pigmented epithelial cells. The 
cells experimented with are situated in the organism between two entirely 
different elements, the retina and the choroid. Each cell is differentiated into 
two entirely different parts, one of which faces the retina and the other the 
choroid. But when the cells are cultivated in vitro, where the environment 
is uniform, the cell ceases to be different on opposite sides. 
We shall now discuss those changes in the medium which affect not the 
form of the cells but their rate of growth. Plasma was originally used as a 
culture medium for the following reasons: 
1. It furnished what seemed to be a natural fluid similar to that in which 
the cells are bathed in the organism. 
2. On clotting, it furnished a framework for the cells. 
3. It would, supposedly, furnish the necessary nutrition. It was soon 
found, as we have said, that the addition of embryonic tissue juice was nec- 
essary for indefinite growth in vitro. Apparently the cells were unable to get 
nourishment from the plasma. The proof that cells obtain their nourishment 
from the embryonic tissue juice rather than from the plasma was the fact 
that they grew just as well in a suitable synthetic salt solution plus embryonic 
tissue juice as in plasma plus embryonic juice. It was also found that with 
a constant quantity of embryonic juice, better growth was obtained with 
plasma from a young than from an old organism. This indicates that plasma 
from an old organism contains substances unfavorable to growth in vitro. 
It was definitely found that the older the animal the greater the in- 
hibiting effect of its plasma. Carrel set out to prove conclusively that 
it was the actual presence of an inhibitory substance, and not the mere 
absence of a growth accelerating substance that made old plasma less 
favorable than young plasma. He did this very simply. If an inhibitory 
44 substance is present, the greater the concentration of plasma in the medium 
the greater the inhibitory effect would be, while, if an accelerating substance 
is present, the greater the concentration of plasma, the greater the accelerating 
effect. Carrel found that the inhibiting effect increased with increase in con- 
centration of plasma. Furthermore, in plasma from an old animal where the 
inhibitory substance is present in large amounts, the increase in inhibitory effect 
increases rapidly with the increase in concentration of plasma, while in plasma 
from a young organism in which less of the inhibiting substance is present 
the inhibitory effect increases slowly with increasing concentration of plasma. 
All these experiments were carried out on Carrel’s 10-year-old strain of fibro- 
blasts. The rate of growth of these in certain media was definitely known. 
He was, therefore, able to realize an old hope—of being able to use a pure 
culture of fibroblasts as a reagent for detecting some of the modifications 
occurring in blood plasma under the influence of age. Applying these results 
to the organism, we see that tissues cease to grow in the adult, not because the 
tissues in themselves become old in completing their necessary life history, 
which involves old age and death, but that their powers of growth cease 
because of inhibiting substances present in their environment. 
Carrel took fibroblasts from organisms of different ages, put them in 
identical environments, and found that although their initial rate of pro- 
liferation varied with the age of the animal from which the tissue was taken, 
after several days the rate of growth was the same for all the tissues. This 
proved that for a given type of tissue the rate of growth was the function 
solely of the environment. Hence, if the environment is properly adjusted, 
immortality of tissues is attainable. Carrel’s chick fibroblasts have now been 
actually growing for ten years, and there is no reason to believe that they 
cannot continue to proliferate indefinitely. So far the fibroblasts have lived 
much longer outside of the organism than they probably would have inside the 
chicken. It is true that a few chickens are reported to have reached the age 
of thirty years—but they are very rare birds. It has been calculated that 
if all the tissue coming from the original culture of a few square mms. in 
area had been preserved and cultivated further, the total volume would now 
surpass that of the sun. This shows that potential immortality is not re- 
stricted to plant tissues, and to certain protozoa, but that it is also a property 
of the tissues of the most highly developed animals. 
The medium, then, determines the rate of growth of fibroblasts. What 
substances can be added to the medium to stimulate growth? It was found 
out very early that embryonic tissue juice was by far the most effective of 
such stimulating substances. This was to be expected, since embryonic tissue 
is the most rapidly proliferating tissue in the organism, and the most hardy, 
longlived in vitro. 
Our knowledge of the factors accelerating growth was greatly increased 
when Carrel managed to get a pure culture of large mononuclear leucocytes. 
When an extract of the medium in which the leucocytes were grown was 
added to the medium in which fibroblasts were growing, the rate of growth 
of the fibroblasts was increased. Thus, by using the fibroblasts as a reagent, 
to test the effects of unknown substances on growth, it was found that leu- 
cocytes in vitro secrete substances which have the same stimulating effect as 
embryonic juice. The next step was to demonstrate that leucocytes secrete 
similar substances in vivo. Carrel produced experimentally connective tissue 
inflammations and peritoneal exudates, which contained large numbers of leu- 
45 cocytes. Extracts from the inflamed connective tissue and from the exudates 
were found to have the same stimulating effect on the growth of fibroblasts 
in vitro as have embryonic juice and extracts from the medium in which 
lucocytes have been cultivated in vitro. We thus arrive at the conception 
of the leucocyte as a cell retaining its embryonic character throughout the life 
of the organism, as a wandering unicellular gland secreting substances which 
stimulate growth. As we have said before, the presence of inhibitory sub- 
stances in the blood, which increase in amount as the organism grows older, 
effectively prevents the proliferation of tissues in the adult organism. There 
is one conspicuous exception to this: In the regeneration of wounds in even 
extreme old age, we have a proliferation of tissue recalling the rapid growth 
of embryonic tissue. It is striking that this rapid growth in an old organism 
in the regeneration after a wound is accompanied by the presence of leuco- 
cytes. Apparently, in wounds the leucocytes are active, not only in opposing 
bacterial invasion but also in secreting in the tissues the material necessary 
for cell multiplication. Furthermore, it is well known that if the wound is 
not irritated, healing is greatly delayed. It is also known that irritation 
causes the invasion of leucocytes. We can now appreciate the true significance 
of irritation, and of the leucocytic invasion of wounds. The conception of 
the leucocyte as a protective mechanism against foreign bodies must also be 
extended. The leucocyte in vitro as well as in vivo has powerful phagocytic 
powers. But in addition leucocytes have the property in vitro of responding 
to a foreign protein, such as casein, by the increased secretion of growth- 
promoting substances. This reaction of the leucocytes is immediate. Fibro- 
blasts respond in vitro to an antigen, such as a foreign protein by the pro- 
duction of antibody, but this immunization of the fibroblasts begins only after 
four days. This would indicate that the first reaction to a foreign protein 
is not the production of antibodies by the tissue cells but the secretion of 
growth-promoting substances by the mobile, unicellular glands, the leucocytes, 
which wander to the spot of infection. 
This new knowledge of the functions of leucocytes, as well as the 
discovery of the changes in the blood with age, was made possible by the 
in vitro technique. When we consider that most of the striking results were 
obtained within the past year or so, there is every reason to believe that this 
method will yield many valuable results in the near future. The work on 
tissue cultures has just begun. 
Baitsell, G. A.: Jour. Exp. Med. 1915, xxi, 455. 1916, xxiii, 739. 
Busse, 0.: Virchaw’s Archives. 1920, ccxxix. 1. 
Burrows, M.: Jour. Exp. Zoo, 1911, x, 63. Anat. Rec., 1912, vi, 141. Tr. Cong. 
Am. Phys. & Surg., New Haven, 1913, 77. Anat. Rec., 1916, x. 335. 
Burrows & Neymans: Jour. Exp. Med., 1914, xx, 1. 
Carrel, A.: Journ. Exp. Med., 1914, xx, 1. 1922, xxxvi, 385. 
Carrel & Burrows: Jour. Am. Med. Assn., 1910, lv, 1379. Jour. Exp. Med., 1911, 
xiii, 387, 416, 562, 571; xiv, 244. 
Carrel & Ebeling: Jour. Exp. Med., 1921, xxxiv, 317, 599; 1922, xxxv, 17, 647; 
xxxvi, 365, 394, 645. 
Carrel & Ingebrigsten: Jour. Exp. Med., 1912, xv, 287, 389, 393, 516; xvi, 165; 
1913, xvii, xviii, 14, 287; 1914, xx, 1. 
Champy, Ch.: Rev. Gen. des Sci., 1913, xxiv, 790; Comptes Rendues Soc. Biol., 
1914, lxxvi, 31. : 
BIBLIOGRAPHY 
46 Champy & Coca: Comptes Rendues Soc. Biol., 1914, lxxvii, 238. 
Drew, A. H.: Brit. Jour. Exp. Path., 1922, 20. 
Ebeling, A. H.: Jour. Ex<p. Med., 1914, xx, 130; 1919, xxx, S31; 1921, xxxiv, 231; 
1922, xxxv, 755. 
Ebeling & Fischer: Jour. Exp. Med., 1922, xxxvi, 285. 
Erdmann, R.: Amer. J. Anat., 1917, xxii; Deutsche Med. Woch., 1920, xlvi, 1327; 
Das Praktikum der Gewehepflege, 1922. 
Fischer, A.: Jour. Exp. Med., 1921, xxxiv, 447; 1922, xxxv, 367, 661; xxxvi, 379, 
393, 535. 
Goldschmidt, R.: Proc. Nat. Acad. Sci., 1915, i, 53. 
Hague, M. J.: Jour. Exp. Med., 1919, xxx, 617. 
Harrison: Jour. Exp. Zoo., 1910, ix, 787; Anat. Rec., 1912, vi, 181; Tran. Cong. 
Ann. Phys. & Surg., New Haven, 1913. 
Ingebeigsten, R.: Jour. Exp. Med., 1912, xv, 397, 169, 421; 1913, xvii, 182; 1913, 
xviii, 412; 1915, xxii, 418; 1916, xxiii, 251. 
Kroutonski & Poliff: Method of Tissue Cultures, 1917. (Russian.) 
Kroutonski & Radzimovska: Jour. Physiol., 1922, lvi, 275. 
Lambert, R. A.: Jour. Exp. Med., 1912, xv, 510; Anat. Rec., 1912, vi, 91; Trans. 
Cong. Chem. Phys. & Surg., 1913, 91; Jour. Exp. Med., 1913, xvii, 499; xviii, 406; 
1914, xix, 398. 
Lambert & Hanes: Jour. Exp. Med., 1911, xiii, 495, 505; xiv, 29, 453; 1912, xv, 
510; 1913, xvii, 499, xviii, 406; 1914, xix, 398. 
Lewis, M. R.: Amer. Jour. Physiol., 1915, xxxviii, 153; Anat. Rec., 1916, x, 287; 
Carn. Contrib. to Emb., 1917, vi, 45; 1920, ix, 191; Jour. Exp. Med., 1920, xxxi, 293, 
1921, xxxiii, 485; 1922, xxxv, 317. 
Lewis, W. H.: Amer. Jour. Physiol., 1919, xlix, 123; Johns Hopkin Hosp. Bull., 
1919, xxx, 81; Jour. Exp. Med., 1920, xxxi, 275; Anat. Rec., 1922, xxiii, 117, 381; Amer. 
Jour. Anat., 1922, xxx, 39. 
Lewis & Felton: Johns Hophin Hosp. Bull., 1922, xxxiii, 112. 
Lewis & Lewis: Anat. Rec., 1911, vi, 195, 207; Am. Jour. Anat., 1914, xvii, 339; 
1917, xxii, 169; Am. Jour. Physiol. 1917, xliv, 67. 
Lewis & Webster: Jour. Exp. Med., 1921, xxxiii, 261, 349; xxxiv, 397. 
Loeb, L.: Anat. Rec., 1912, vi, 109; Jour. Med. Research, 1920, xl, 509. 
Loeb & Blanchard: Amer. Jour. Physiol., 1922, lx, 277. 
Losee & Ebeling: Jour. Exp. Med., 1914, xix, 593. 
Macklin: Carn. Contrib. to Emb., 1916, xiii. 
Maximoff: Arch. Russe d'Anat., d’Hist., et d’Emb., 1916, I; Comptes, Rendues Soc. 
Biol., 1917, lxxx, 225, 235, 237. 
McWhorter & Whipple: Anat. Rec., 1912, vi, 121. 
Raus, P.: Jour. Exp. Med., 1913, xviii, 183. 
Raus & Jones: Jour. Exp. Med., 1916, xxiii, 549. 
Russell: Scien. Report Imp. Cancer London Research Fund, 1921, vii, 19. 
Smyth, H. F.: Journ. Exp. Med., 1915, xxi, 103. 
Uhlenhuth, E.: Jour. Exp. Med., 1914, xx, 614; 1915, xxii, 76; Arch, of Ent. 
Mech., 1916, xiii, 168. 
Walton, A. J.: Jour. Exp. Med., 1914, xix, 121; xx, 554; 1915, xxii, 194. 
47 TNTRAVITAL STAINING AND ULTRA-VIOLET 
PHOTOGRAPHY 
IN considering this subject, it is deemed advisable to preface a few gen- 
eralities concerning its importance to the field of anatomy as a whole, 
and specifically to that of histological research. The primary service of 
anatomy to medicine is contained in the fact that it enables the scientist to 
understand and then to correlate the mechanism which carries out the func- 
tions of the living organism, and it is to the understanding of this mechanism 
in its finer and more fundamental details that histology contributes for the 
most part. Now histological study for a long time consisted solely in the 
microscopic observation of animal structures which had been prepared from 
tissues after death, and subjected to fixation and staining processes; these 
factors were considered by many to have so acted on the delicate cell com- 
ponents as to render all observations invalid more or less according to the 
circumstances involved; it was argued that post-morten autolysis, destructive 
action of dyes, and the like, had produced afterfacts which jeopardized the 
very foundations of histological belief. In response to these accusation have 
arisen the investigations of cell and tissue structure through intravital stain- 
ing and ultra violet photography. Here the structures are studied in the 
living state, or under conditions approximating it sufficiently closely, so that it 
is possible to verify, and in some cases improve on, the theories and conclu- 
sions of previous microscopic investigations. 
In the consideration of intra-vital staining, which will first be dealt with, 
it is primarily necessary to bear in mind that it is a method, and not a theory, 
so there must be a lack of continuity between parts of the work done by 
different individuals; again, the subject, though still comparatively new, has 
grown to proportions which prohibit detailed examination in a paper neces- 
sarily so short; it will therefore be deemed appropriate to restrict this expo- 
sition to more general treatment, with specific presentation of only a few 
important or typical examples, leaving it to the reader to satisfy his further 
curiosity from the appended bibliography. 
The history of intravital staining dates from the last quarter of the 
past century, and its inception is associated with, if not ascribed to, the work 
of Erlich, who stood out as the pioneer, and upon whose leadership subse- 
quent investigations have largely depended. It was found that certain dyes, 
such as methylene blue, neutral red, or trypan blue, could be injected into the 
living organism, and that the tissues, though unharmed physiologically, would 
receive the stain, and could be examined microscopically, either by taking a 
section from a freshly frozen piece of living tissue, or bv actual examination 
of the organism itself while yet alive. The technique is exceedingly complex 
and difficult, requiring extremely careful manipulation and exact conditions 
in order to preserve as nearly as may be the normal state of the living 
material. 
48 Probably the most exhaustive and brilliant collation, as well as investi- 
gation of intra-vital staining, has been done by W. V. Mollendorf, whose 
article in the Ergebnisse der Physiologie, Vol. VIII (1920), gives an account 
of various applications of the methods, together with results obtained. First 
of all it was found that a typical cell on being subjected to vital stain, would 
appear to absorb it in granular deposits within the cytoplasm. These might 
later merge in a definite form, or collect in a group, and be extruded with 
waste or unused material. Now it was found, furthermore, that certain cells, 
or groups of cells, would seem to exercise a selective sort of function, so that 
while one set might take a certain dye another would not. Also, as might 
have been expected, different dyes affected the same cell in strikingly different 
ways, and one type of stain had varied effects on cells of unidentical character. 
There are several methods of treatment; the dye may be injected intra- 
venously or by peritoneal injection, or it may be applied to freshly excised 
tissue from a living animal. Subcutaneous injection may be used for some 
types of work, but its effect frequently coincides with that of the other 
methods. 
Mbllendorf describes the successful staining of many types of tissue and 
organs, eg.: Central nervous system, endocrin glands, lymph glands, genito- 
urinary organs, blood, muscle tissue, mammary glands and others. In the 
demonstration of nerve-endings, the use of vital staining is very valuable, and 
is regarded by some authorities as superior to other methods. In some 
instances it is quite certain that the value of vital staining has transcended 
all other procedures for investigation of cell structure; an example of this 
will be given at a later point. 
Authorities differ very strikingly on the precise nature of the staining 
action—some aver that the dye enters into chemical relationship with the 
protoplasm of the cell itself; others claim that unless the stain is of a de- 
structive, or at least reformative nature, it merely enters the cell body with 
the ordinary food of the cell, and remains suspended like other unused 
material in the cytoplasm until execreted. This is closely linked with the 
belief of yet another “school” which holds the cell action to be a sort of 
phagocytic mechanism, simply seeking to defend the organism against foreign 
material. This is supported by the observable actions of leucocytes on vital 
stain injections, as well as by other factors, but the question as a whole is 
handled in greater detail by another paper in the series on living cell reactions 
to foreign bodies. 
Before going into the more detailed examples of intra-vital staining, it 
is proper to mention the physiological significance of this method. Obviously 
the value of such a process is very great, for by it the physiologist is enabled 
to observe the actual behavior of the living cell, noting details of movement 
and function which no series of preparations or pictures can quite duplicate. 
As an example of this we have the classic work of E. R. and E. L. Clark on 
the vitally stained tails of living tadpoles (c. f. Amer. Jour. Anat. XXI, Anat. 
Record XIV and XV) in which they observed cell and blood reactions over 
long periods through the conveniently transparent caudr 1 appendages of their 
subj ects. 
One of the most significant pieces of work in the field of intra-vital 
staining was that done by Evans and Scott, whose report in Publication 273 of 
the Carnegie Institute “On the Differential Reaction to Vital Dyes Exhibited 
by the Two Great Groups of Connective Tissue Cells” stands out conspicuously 
49 as an example of what intra-vitam dyes can do. These brilliant workers con- 
ducted a series of exhaustive experiments with different dyes under varying 
conditions, and their conclusions are here appended: 
“The two great cell strains of mammalian connective tissue; the fibro- 
blasts and macrophages—exhibit a pronounced and characteristic difference 
in their reaction to intra-vitam acid dyes,” they point out. This is shown 
by the distinct responses to dyes, in the size and number' of dye ‘granules’ and 
associated characterstics. Mitochondrial apparatus of these cells is apparently 
not stained electively by these vital acid dyes. The dyes do not enter into 
chemical combination with the cells, but are accumulations of high-colloidal, 
flocculated or crystalline dye-stuffs in fluid. The ingestion of the dyes is said 
to be associated with a process of segregation from the living cell protoplasm 
by an “apparatus” composed of granules, vesicles, and vacuoles created often 
by the cell in addition to those present. It was shown that the macrophage 
stored more dye, but less permanently than the fibroblast type of cell. 
The physiological and histological importance of such observations is too 
obvious to bear elaboration; it but remains to point out the value of vital 
stains in another field, as shown by Bensley in his Harvey Lecture (1914-1915) 
on the “Structure and Relationships of the Islets of Langerhans.” In this 
remarkable announcement, Bensley pointed out that he had been enabled to 
settle an old and long-contested point concerning the islets in the pancreas 
by a system of vital staining, in which he was able to demonstrate by two 
different stains the islets and the ducts of a single pancreas. 
An injection of janus green (solution I in 15,000 normal salt) into the 
aorta promptly stained the whole pancreas blue; if the pancreas was now 
covered and air excluded, the tissue reduced the dye to a safranin, but the 
islets proceeded so slowly in this matter that presently they were the only 
blue part, the rest being intense carmine in color. The whole might now be 
fixed permanently by ammonium molybdate injection in the ducts, alcohol 
fixation, and toluol clearing. Then by breaking it up into fragments, and 
putting these on slides it was possible to count every island without sectioning, 
and without fear of recounting any one; also one could ascertain the pro- 
portion of islet content. Neutral red injections gave the same opportunity, 
but could not be made permanent. Now an injection of pyronin of methylene 
blue was found effective as a strain for the duct system. 
By the complete survey which these invesigations afforded, Bensley was 
able to make his conclusions on the islets of Langerhans which have since 
proved so valuable to the field of medicine. 
These are only isolated instances which are taken from the great mass 
of data to show that intra-vital staining, however new, has taken its place as 
an accomplice and assistant to histological study in particular, and science in 
general. 
Ultra-Violet photography, like Vital Staining, is also a method, and one 
that in a general way pursues the same ends. While the chemist endeavors 
to form a philosophical and pictorial conception of life processes in terms 
of molecular arrangement and change, it has been the histologist’s ambition 
to observe with his own eye these phenomena being carried out. Vital stain- 
ing permits of this in some measure, but photography with ultra-violet rays 
opens an even greater field. Vital dyes show us at best a somewhat abnormal 
condition, but roentgen rays not only exhibit living matter but show it in 
the unstained state. It is difficult to overestimate the importance of this. The 
50 cell which heretofore revealed its form only through the agency of rather 
obscure reactions—a word in itself implying change—may now be photo- 
graphed in the mormal fluid medium with great precision. Furthermore, the 
method has a marked embryological value, since the subject may now be 
studied by a series of photographs of the same cell rather than by a number 
of stained sections taken from different cells. Aside from these considerations, 
which have an enormous philosophical importance in the field of biology as 
a whole, this method marks a tremendous advance in the purely mechanical 
problem of microscopic technique. This comes about through the employment 
of the short wave length, which, as will be explained below, constitutes the 
only known method for increasing the magnifying power of the present 
microscope. This was the twofold stimulus that urged Boys, Siedentopf, and 
Kohler to make their initial investigations of what had been up to that time 
an entirely untouched field. 
It was Siedentopf, in 1903, who indicated the possibilities of visibility 
of ultra-microscopic particles for fractions of wave lengths of light, and in 
1904 August Kohler announced the result of his researches, which have since 
become classic in the annals of microphotography. The technique which he 
developed, wherein he employed fused quartz lenses exclusively, following the 
earlier suggestion of Boys, remains, with a few slight modifications, the 
standard of today. It must be borne in mind that even with this precedent, 
ultra-violet photography is far from simple. The obstacles in the path of an 
investigator are very definite. To begin with, the apparatus is exceedingly 
complex and! expensive. Furthermore, it appears to be enormously difficult 
to master the mere details of operation, and the success of a photograph is 
highly problematic. In fact, Ernst and Wolbach declare that a man who is 
proficient in ordinary microphotography requires several years of experience 
with ultra-violet work in order to obtain even a reasonable degree of success. 
However, the potentialities of the method seem great enough to compensate 
more than adequately for this expenditure of time. 
Abbe, in his study of microscopy, came to the conclusion in 1876 that 
microscopic efficiency depended upon magnifying power, perfection of the 
union of rays, and the size of the aperture admitting cones of light. He 
further declared that in the first and last of these essentials efficiency had 
already been obtained, and to perfect the second one he developed his apochro- 
matic microscope. Some time later he qualified his comments upon magnify- 
ing power by asserting that efficiency had been obtained only in respect to 
visible light, and that advances were possible in this direction by the use of 
fight rays beyond the violet end of the visible spectrum. This conclusion rests 
upon the principle of resolution. With ordinary light wave length fluctuates 
within fairly narrow limits. For white light we may take the length of the 
central yellow green rays as standard, that is, about 550 rr. in air—with a 
slight variation for media of different refraction. By the use of filters, then, 
which exclude other lights, shorter wave lengths may be obtained which are 
more easily photographed than seen, although this process requires special 
apochromatic devices to correct the resulting observations. The decrease in 
the wave length brings a corresponding increase in the resolving powers of 
the lens, and this leads directly to greater possibilities of magnification, and 
greater clarity. The term “resolution” may be explained as follows: Let us 
assume an ideally perfect double convex lens, beneath which is a perfect 
point source of light—A. The rays will diverge until they reach the lens, and 
51 then converge as the central part is retarded. They will meet at a point, 
giving an intense point image. It is obvious that this point will be surrounded 
by a diminishing series of dark and light hands caused by the coincidence 
and mutual neutralizing effects of the vibrations. Manifestly the image from 
another point source of light—B—will, with a certain degree of proximity, 
be merged with the image of A and but one light will be seen. This condi- 
tion is known as failure of resolution. It follows that in order to obtain 
resolution the first dark hand from A must be superimposed on a similar 
one from B to secure separation of the images. That is to say, the distance 
between the points of light must be the equivalent of two one-halves of a 
wave length. This interval will induce the crests and troughs to coincide, and 
produce the essential dark intervening hand. The implication is, therefore, 
that any given ray from point B must travel just one wave length further 
than a corresponding one from A. The geometry of the figure thus con- 
structed will show us that the shorter this wave length is the nearer A and B 
may be together and still retain their duality of image. This is called greater 
resolution, and on it obviously depends the possibility of increased magnifica- 
tion and clarity in microscopic work. Since ultra-violet rays have the shortest 
known wave length, their relation to microscopic efficiency is apparent. 
The actual process of photographing these rays presents numerous tech- 
nical difficulties, and the apparatus, originally designed by Kohler, has been 
somewhat modified by Barnard. The following description is taken from the 
last named author. The objectives are three in number, made of fused quartz, 
and possessing a focal length of 6 mm., 2.5 mm. and 1.7 mm., which correspond 
to an effective numerical aperture of 2.50, 1.7 and 0.7 respectively. The last 
two are glycerine immersion, the refractive index of glycerine being 1.447. 
The cover glasses used are of optically worked fused quartz, the slides also 
being of fused quartz; they are mounted on a special carrier insuring uniform 
distance from the objectives. The equipment includes five quartz occulars, 
having an initial magnification of 5 to 20, which gives the camera a magnifi- 
cation power of 200 to 3,600 diameters. Barnard has not yet been able to 
photograph clearly with the highest magnification. The substage condenser is 
of quartz with an adjustable duplex top. Light is furnished by a high 
tension discharge in air between cadmium or magnesium electrodes, these 
metals being chosen for the intrinsic properties of their ultra violet spectra. 
A spark gap of 5 cm. receives the heavy discharge of low potential from an 
induction coil of special design. This spark throws its beam through a quartz 
lens at right angles to the optic axis of the microscope, and is filtered by two 
quartz prisms of opposite rotation. The image of the spark is focused by 
means of a disk of unranium glass placed below the substage condenser. To 
focus the final images, a fluorescent searcher eye-piece is mounted above the 
occular, and the focusing is done by means of an auxiliary magnifier. After 
visible focusing, the fine adjustment is moved a predetermined amount for 
any wave length being used. The camera now replaces the searcher eye- 
piece, and the image is projected so as to be in focus for the plane of the 
plate. The latter must be of exceptionally fine grain, having the maximum 
quantity of silver salt and the minimum of gelatine. Such a plate is made 
by the Eastman Kodak Company. An exposure as short as 2 seconds 
may be successful, although it is commonly longer. This method of ultra- 
violet photography, in which great care is taken to employ monochromatic 
light spectroscopically analyzed, eliminates achromatism entirely. 
52 Cells and tissues to be examined are mounted unfixed, undried, un- 
hardened in such fluids as normal saline, lachrymal, or Ringer’s solution. 
Inasmuch as death results in increased opacity to ultra-violet rays, it is 
essential to have the material in the living state. The physical principle 
involved in this photography is embodied in the fact that different substances 
have different absorption indices for ultra-violet rays, and when the picture 
shows differences in substance throughout a cell it is safe to infer that they 
correspond to structures in the cell. Bovie has conducted elaborate re- 
searches into this aspect of the subject, using fluorite rays and reducing his 
results to tabular form, which may be employed in the future to determine 
the chemical nature of the structures observed. A very suggestive field is 
thus offered. These considerations serve to show more clearly the tremendous 
importance of the method in its revelation of living phenomena. It may be 
argued that the rays themselves alter the structure of the cells, which would 
undoubtedly be true if the exposures were several hours in duration, but 
Bovie, in his experiments with paramecia, has shown that complete cytolysis 
results only after an exposure of far longer duration than that necessary for 
photography. By submitting these forms to the action of the light for rela- 
tively long periods, he discovered the only change to be an inhibition of cell 
division, which after a time was followed by a great acceleration, showing 
the compensatory tendency of living material. 
In attempting to collect some results of this method which would be 
striking enough to justify its enormous theoretical value, one encounters con- 
siderable difficulty. Its amazing technical complexity, coupled with the paucity 
of investigators, makes choice of illustration quite limited. If the results have 
not as yet been the basis of new theories or the means of refuting old ones, 
it has at least corroborated existing conceptions. The pictures produced may 
not have revealed anything radically new or important, but they afford a 
thoroughly satisfying certainty that many of our present beliefs are true. 
These photographs have revealed living forms with a fineness and clarity of 
detail never achieved before in microphotography. We can derive much 
satisfaction from the knowledge that there is at our command a technique 
capable of establishing any obscure point in histology whose importance war- 
rants such laborious investigation. In a paper of this nature where the 
reproduction of plates is impossible, it is obvious that a detailed description 
of a great number of photographs would be cumbersome and valueless. It 
may be of some profit, however, to indicate the general nature of some of 
them. Ernst and Wolbach have produced remarkably clear pictures of the 
striations in potato starch, together with some highly suggestive stages in 
the cytoplasmic reorganization of bacteria. The typical ultra-violet plate is 
devoid of high lights and shadows owing to its thinness, but lines of demar- 
cation are extraordinarily distinct. Kohler’s initial results in the field are also 
well worthy of mention. At a magnification of 1,300 diameters he obtained 
a photograph of an epithelial cell from the gill plate of Salamandra maculosa 
which is in the process of mitotic division. It is a late prophase and the 
amphiaster is very distinct; the symmetry of this figure, together with the 
decisive etching of the astral rays is most interesting. In two photographs 
of living filaments of Cyanophycea he obtained an almost complete series of 
mitotic figures. All Kohler’s work is striking, but essentially he was a 
pioneer, more concerned with the physical problems of his art than with the 
biological implications thereof. Research in this field is now being actively carried on, notably by S. E. Barnard, and by Bovie and Mudd of Harvard. 
The last-named investigator expects shortly to add to the literature of the 
subject, and to announce the result of several years’ work at Cambridge. 
The value of the methods which we have discussed lies ultimately in 
the possibilities which they admit rather than in what has been accomplished 
hitherto. But anything which serves to lessen the gap between scientific con- 
ceptions and the almost infinitely diverse complex of unseen form and move- 
ment upon which they rest demands the consideration of all those engaged 
in the pursuit of fact. It is impossible to foretell the effect of these) two new* 
departures in the future on such an established science as histology, but we 
venture to predict that should any discovery radical enough to change the 
whole tenor of the field be made, it will come from one of these sources. 
BIBLIOGRAPHY 
Arnold, J.: Virchows Arch. Nos. 71, 73, 151, 159. Also “Ueber Plasmastrukturen 
und ihre funktionelle Bedeutung. Jena, Gustav Fischer. 
Bayliss, W. M.: Principles of General Physiology London, 1915. 
Bensley, R. R.: “The Islets of Langerhans,” Harvey Lectures, 1915. 
Clark, E. R. and E. L.: “On the Reaction of Certain Cells in the Tadpole’s Tail 
toward Vital Dyes,” Anat. Record, xv, ibid xiv. 
Cowdry, E. V.: “Mitochondrial Constituents of Protoplasms,” Carnegie Inst. 
Wash. Pub. No. 271. 
Cunningham, R. S.: “The Reaction of Cells Lining the Peritoneal Cavity, etc., to 
Vital Dyes.” Amer. Jour. Anat., vol. 30, No. 4, 1922. 
Ehrlich, P.: Deutsche Med. Wochenschr. 
Evans, H. M.: “Macrophages of Mammals,” Am. Jour. Physiol., vol. xxxvii, 1915. 
Evans & Scott: “On Differential Reaction to Vital Dyes Exhibited by the Two Great 
Groups of Connective Tissue Cells.” Carneg. Inst. Wash. Pub. No. 273. 
Von Mollendorff, W.: “Vital farbung mit sauren farbstoffen,” Ergebnisse der Physi- 
ologic, vo. xviii, 1920. 
Vogel & McCurdy, V. F.: Arch. Int. Med., 1913, xii. 
Sappington : Ibid. 1918, xxi. 
Ultra-violet Photography 
Barnard, J. E.: “Microscopy with Ultra-Violet Light,” Nature. London, 1920-21, cvi. 
Bovie, W. T.: “Approximation of the absorption Index of Fluorite Rays in Pro- 
toplasm,” Jour. Med. Res., xxxix, Nov., 1918. 
Bovie, W. T. and D. M. Hughes: “Effect of Fluorite Rays on Division of Para- 
mecia,” Ibid, xxxix, Nov., 1918. 
Ernst, H. C. and S. B. Wolbach: “Ultra-Violet Photomicrography,” Jour. Med. 
Rex., xiv, 1906, No. 3. 
Sabine, W. C.: “The Optical Advantages of the Ultra-Violet Microscope,” Ibid, 
xiv, 1906, No. 3. 
Kohler, August: “Mikrophotographische Untersuchungen Mit Ultra-Violettem Licht,” 
Zeit. F. Wiss. Mikrosk., xxi, 129, 1904. 
Kohler, August: Ibid., xxi, 273, 1904. 
54 THE INTERSTITIAL GLAND OF THE TESTIS: 
ITS HISTOLOGY AND SIGNIFICANCE 
T> HE interstitial cells of the testis were first reported and described in 
1850 by Leydig—and consequently have been termed the Cells of Leydig. 
He described the cells as round and clear, analogous to embryonic con- 
nective tissue, occasionally with vacuoles, and always containing fat and pig- 
ment granules. Four years later Kolliker showed their presence in the Medias- 
tinum and connective tissue septa, and also under the Tunica Albuginea, as 
well as between the seminiferous tubules, as related by Leydig. In 1903 Bouin 
and Ancel in view of the probable glandular function of these cells, applied 
to them the appellation interstitial gland of the testis. 
Intestinal cells exist in all the vertebrates that have been examined, with 
the possible exception of a few birds. The degree of development of the cells 
is subject to extensive variation—nothing like uniformity being discernible 
in any two species. 
According to Bouin, Ancel, Chapin and others these cells make their ap- 
pearance in the genital tract and become functional before the formation of 
definite germ cells. Whitehead, working with embryonal pigs demonstrated 
that the intertubular tissue of the testis in stages immediately preceding the 
appearance of interstitial cells is a “Mesenchymal structure derived from the 
mesenthelium of the genital ridge.” Histologically this is a connective tissue 
syncytium consisting of cells and an exoplastic network of fibrils. The cells 
are practically devoid of cytoplasm and consist of naked nuclei with fragments 
of cytoplasm at one pole. The interstitial cells develop from this tissue by 
growth of cytoplasm. The early cells are quite plainly branched. These 
branches, however, disappear in subsequent rapid growth of the cells in size 
and numbers. 
In the pig these cells pass through two phases of growth with an inter- 
vening phase of atrophy. The cells appear at the 2.4 cm. stage of the embryo, 
and grow rapidly to the 3.5 cm. stage, then follows the period of atrophy 
during which the cells return almost to their first stage of bare nuclei. The 
climax of this process is reached in the embryo of 14 cm. Simultaneously 
there is an extensive growth of the seminal tubules so that they are greatly 
convoluted and the intertubular spaces correspondingly narrowed. 
The second stage of growth of these cells begins at the 20 cm. stage and 
attains its maximum in the embryo at 28 cm. very near to term—at which time 
they have increased enormously. 
In the human embryo, Felix found that the interstitial cells develop early, 
i. e., in embryos of 45 mm. before the formation of definite germ cells. The 
early cells are easily recognized by their large size and nuclei which contain 
a dearth of chromatin. After the fifth month there ensues an apparent 
quiesence, during which formation ceases until after puberty, when they 
55 appear again in great numbers. Another phase of retrogression follows, which 
in turn is followed by a renewed increase. 
In the adult human testis interstitial cells vary considerably in numbers 
as between individuals. No marked difference between right and left testicle 
has been noted. They occur singly, in groups or in acinus-like clusters, and 
are closely related to blood vessels. They are easily identified and can be 
distinguished from connective tissue cells by their general appearance, and 
by the fact that they do not stain with vital dyes such as trypsan blue. The 
nuclei are usually single and spherical, but double nuclei have been seen. The 
nuclei are poor in chromatin and rarely contain distinct nucleoli. In lower 
forms, and probably in man, the cytoplasm of these cells has a striking af- 
finity for mitochondrial stains. This may be due to a slightly acid reaction 
on the part of the cytoplasm. Winiwarter found in man that mitochondria, 
occurring as granules and rods with an occasional filament, were fairly evenly 
distributed throughout the cytoplasm. Small clusters are exceptional. The 
same investigator described the centrosome in the human interstitial as spher- 
oidal or rod like. If the nuclear membrane is indented, as is often the case, 
the centrosome may be found in the concavity . Two centrosomes may occur 
in the singly nucleated cells, and in the bi-nucleated as many as four have 
been seen. No radial arrangement of cytoplasm granules exists about the 
centrosomes to indicate it to be a dynamic center. 
Fat granules appear in various amounts. They occur in clumps and arc 
distributed through the cytoplasm without apparent order. They are believed 
to increase with age. 
Pigment granules appear at about 21 years and become abundant. Lehrt 
believes this pigment to be a lipochrome. Often there is a sharp contrast 
between the pigmented and non-pigmented portions in the same testicle. This 
has led to the belief that the pigmented cells are undergoing degeneration, 
although there exists no noticable difference in the size of the cells or in 
the nucleus—cytoplasmic ratio. 
Duesberg alone has studied the reticular apparatus of these cells. No trace 
of such a system is visible in living unstained cells, but by Cajal’s uranium 
nitrate method a network was shown. It varied somewhat in different speci- 
mens, but evidently indicates some regional variation in the properties of the 
cytoplasm because the location of the network is quite definite—always in close 
assocation with the centrosome. 
In discussing the significance of the interstitial gland, we shall first try 
to prove that the testis, specifically, the interstitial cells therein, may be called 
an internal secretory organ. Next, in describing the functions of the internal 
secretion we shall deal with the influence of the testicular hormone upon the 
development of the generative organs and upon the nervous and particularly 
the vasomotor apparatus. Following that, we shall attempt to explain the 
phenomenon of rejuvenescence by testicular transplants and its relation to the 
interstitial gland. We then will discuss the relationship of the latter to other 
endocrine glands, its influence on metabolism, and finally, the question of sex 
intergrades. 
We found that in the primitive organisms there was no specific tissue set 
apart for reproductive purposes. With the evolution of greater complexity of 
structure, there was set apart a definite reproductive tissue. This tissue is 
Significance 
56 differentiated early in the embryonal life of the individual organism. Asso- 
ciated with the division of the plasms, the germ plasm from the somatoplasm, 
there appeared reproductive tissues of two types; that giving rise to male 
and that giving rise to female elements. The appearance of these two types 
of reproductive tissue assocated with somatic divergences, established sex. 
Some somatic differences consisted primarily in the system of outlets, the 
genital organs so adapted as to insure the more certain fertilization of the 
egg. There arose other characteristics associated with this phenomenon, those 
by which the sexes are differentiated, namely, the secondary sexual charac- 
teristics. 
In addition to the structual and functional differences between the sexes 
have arisen the sexual instincts. In the higher forms these instincts or as many 
prefer to call them “reaction impulses” bring the male and female together at 
the breeding seasons, control the behavior of the individuals towards each 
other—courtship, the union of the sexes—copulation—or its equivalent, and 
finally direct the various activities involved in the building of the nest and 
the rearing of the young. 
There is no doubt that the secondary sexual characters in the male are 
due to an internal secretion on the part of the testes. It is well known that 
castration in man before the age of puberty prevents the growth of hair on 
the face and arrests the growth of the thorax, pelvis and the larynx. Thus 
it is possible to preserve the voice of childhood. It is stated that the practice 
of castrating boys for the cathedral choirs in Rome was carried out until 
1878. Male sopranos or sopranoists were formerly a leading feature of 
musical life. Perhaps the most convincing evidence of the dependence of the 
somatic structures related to sex upon the primary reproductive organs is 
afforded by the results of cross grafting of gonadal tissue into previously 
castrated animals. Steinach and Sand have clearly shown that the ovaries 
of the female rat and guinea pig can be successfully grafted into previously 
castrated males. The “feminized males” develop characters peculiar to the 
female. 
The older physiologists exemplified by Xussbaum thought that the rela- 
tionship between the interstitial cells of the testes and the secondary sex 
characters was accomplished by influences exerted through the nervous system. 
However, the results obtained by the gonadal tissue transplantation, as men- 
tioned above, proves this theory untenable. It is interesting to note that 
preparations and extracts of reproductive tissue serve a similar purpose. 
(Massaglia.) Hence the testes may be considered as organs of internal 
secretion. The exact manner in which the gonads exert their influences upon 
the somatic structures, however, remains to be demonstrated. 
At present there is no evidence that the secondary sex characters are in 
any way assocated with the activities of the sperm-producing cells. Cn the 
contrary there is a wealth of evidence which indicates that these characters 
are dependent upon certain cells lying in the interstices between the semini- 
ferous tubules, viz.: the interstitial cells. 
Many facts, demonstrating that the interstitial cells are responsible for 
the internal secretion of the testes, are revealed by the studies of the selec- 
tive action of the X-rays, vasectomy and undescended testicles. The work of 
Ragaud and Subrenil shows that the action of X-rays upon the male testes 
renders the animal sterile while the secondary sexual characteristics are un- 
57 impaired. Histological examinations have clearly shown that the X-rays 
while, destroying the germ cells, fail to alter the interstitial cells. 
According to Bouin and Ancel ligation of the vas deferens in animals 
results in the cessation of spermatogenesis. On the contrary, the interstitial 
cells retain their morphological and functional integrity indefinitely, and as 
long as these remain, alteration of the stigmata (general make up) of the 
sex does not occur. 
Hyperplasia and hypertrophy of the interstitial cells appear always to 
accompany both imperfect development and secondary atrophy of the semi- 
niferous tubules (Tuck). Cryptorchid animals or those possessing imper- 
fectly descended testicles may be considered intermediate between castrated 
and normal individuals in regard to genital glands, sexual instincts and char- 
acters. Not infrequently there is a minimal development, or an entire lack 
of interstitial cells; consequently the apparent degree of maleness is determined 
by the degree of development of these cells. (Bouin, Ancel, Toolen.) 
The question arises whether or not the sustentacular cells are partially 
responsible for the production of the testicular hormone. From the experi- 
ments of Hanes, it has been fairly definitely established that their functions 
are limited solely to the nutrition of the spermatic elements. On the other 
hand the morphological position of the interstitial cells, as seen from their 
intimate relationship with the rich capillary meshwork surrounding them, 
suggests the possibility of a close relationship with the body fluids or dis- 
tributors of internal secretions. 
The facts that the accessory sexual organs and the secondary characters 
of the sex appear, and are maintained in association with the interstitial cells 
is alone strong evidence in support of the theory that these cells are responsible 
for the hormone production of the testes. 
We shall now discuss the functions of the internal secretions of the testes. 
We find that in the development of the embryo vascularization of the genera- 
tive tissue precedes the appearance of sexual genitalia. Therefore, it would 
seemi that some secretion passing from this tissue into the blood influences the 
appearances of these organs. In the case of two sexed twins of cattle the 
female as a rule is sterile, whereas the male is normal and fertile. The 
female, commonly called the free-martin, has the internal genital organ of a 
male and the external genital organs of a female. The facts that the chorionic 
blood supply of the twins is common, that this chorionic fusion occurs at or 
about the time of sex differentiation, and that the testes of the male begin 
to develop before the ovary of the female, point to the conclusion that some 
internal secretion from the testes passes into the common blood stream and 
affects the sexual developments of the female. Such an explanation of the 
factors, resulting in the formation of the free-martin, lends weight to the 
argument of Van der Broek, who contends that the cause of pseudoherma- 
phroditism is an imbalance of gonadal hormones between mother and foetus. 
Puberty, a period ushered in by an enormous proliferation and activity of the 
interstitial cells, and ripening of the germ cells, is further evidence to show the 
influence of the testicular hormone upon the development of the generative 
organs. 
What influence has the internal secretion of the testes upon the nervous 
structures and their functions? At puberty inactive and dormant nerve centres 
acquire specific sensibility. This storm and stress period and the psychic un- 
rest accompanying it, is paralleled by an increased vitality and great nervous 
58 activity in most animals during breeding season. Removal of the testes of the 
frog results in the loss of these nervous characteristics of the rutting season. 
Testicular transplants in such frogs are sufficient to establish these seasonal 
changes; hence, the testicular substance either acts directly upon the nerves 
or upon the muscles supplied by certain of them. 
It is generally accepted that stimuli acting upon our nervous system control 
our behavior and temperament. The dispositional characteristics of the eunuch 
show an influence of the internal secretion of the testes upon the nervous sys- 
tem, similar to that of external environmental stimuli. It is reported that 
eunuchs of Constantinople are avaricious, illogical, obstinate, possess little 
judgment and accept information without proof. Their mentality is often 
deficient and they are very fanatical. 
From experimental work of Wheelon and Shipley it is found that the 
presence of testicular transplants in dogs previously castrated is sufficient 
partially to reinstate normal vasomotor irritability. This shows that castra- 
tion results in a lowered irritabilty of the vasomotor apparatus because of 
interstitial want. 
Recent experiments by Sand and More have shown that testicular trans- 
plantations have resulted in a phenomenon commonly called rejuvenescence. 
The “puberty gland” of Steinach, as mentioned before, is meant to designate 
the internal secretory organ of the testis—or the interstitial gland, in dif- 
ferentiation from the external secretary organ of the testicle. In a recent 
article in the New York Medical Journal, Dr. C. K. Lydston describes a re- 
markable case of testicle implantation from its clinical aspect, it is as follows: 
Age of subject—34 years; suffering from hypopituitarism. Subject was 
badly nourished and psychically much depressed. The development of sexual 
organs was about that of a child one year of age. No sexual activity ever 
had been experienced. Patient was inefficient mentally, physically, and sexually. 
It was an apparently hopeless case, his age seeming to be an unsurmount- 
able obstacle to success. Finally, a left scrotal implantation of a single tes- 
ticle was performed upon this patient. The material used was taken from a 
subject 18 years old, dead of skull fracture. The gland was removed 24 hours 
after the death of the donor, and refrigerated for 30 hours. Primary union 
took place, and the patient was up and about with suspensory on the 10th day. 
Considering the age and other circumstances the effects of implantation in 
this case were astonishing. Marked improvement in nutrition and general 
health of the patient was evident within a few weeks. His color improved, 
and he became cheerful. There was an increase of eight pounds in weight. 
Within eight weeks after implantation the patient complained of frequent and 
violent erections, and some days later indulged in coitus, experiencing sexual 
manifestations at various times thereafter. 
Since the operation there has been a marked increase in the growth of 
the axillary and public hair, and the patient now is compelled to shave weekly, 
an entirely new experience for him. His mental and physical efficiency have 
greatly increased after the operation. The testes have greatly increased in size 
as is true of the penis. Orgasm and emission both are experienced. Condi- 
tions still are improving. 
In the author’s opinion, the result in this case will be permanent, because 
of the marked development of the patient’s own testes. It is believed that 
practically all, if not all, such subjects, if operated on, at or about the usual 
age of puberty, can be taken through puberty, and will show sex development, 
59 with corresponding secondary masculine sex characteristics, approximating the 
normal more or less closely. 
As to the permanency of cases like the foregoing, it is held that, even 
where, after a greater or less interval, a repetition of the implantation is 
demanded, the operation is still a great step in advance in the treatment of a 
class of cases hitherto regarded as hopeless. There is no question as to the 
uniform success of a properly performed implantation in such cases when 
performed at a reasonably early period after the loss of the patient’s own 
glands. One is convinced that by implantations performed at varying periods 
the results can be sustained indefinitely. 
, In such a homo transplant as described above, there is an immediate loss 
of spermatogenic function with complete degeneration of the spermatozoa 
forming elements. The interstitial cells of the transplant remain and increase 
iii number, retaining their staining preperties the same as before the opera- 
tion. Just how long the interstitial cells live and function after a successful 
homo transplant is still a question subject to hspute. It is believed that if 
there is a successful take, they will live indefinitely. If one does not have a 
take, the interstitial cells degenerate within a few months. In auto transplants 
the same phenomena occur as in the homo transplants. The only difference is 
that there is a larger percentage of takes. 
All symptoms due to senility including sexual impotence, as a rule, improve 
after the operation. And this is what we must emphasize—the success or 
failure of the operation depends not only upon the ability of the puberty gland 
to renew or increase activity, but also upon the response that the other duct- 
less glands, on the whole endocrinological system of the patient, will give to 
the renewed output of gonadal hormone. As long as the new activity of the 
interstitial gland lasts and as long as the other endocrine glands respond to 
its impulses, the patient’s senility is postponed, partly at least, or its advance 
checked. 
Whether a prolongation of life is obtained is impossible to say. So far, 
in no one of the successful cases has the patient come to a second senility or 
has died, except, of course, of intercurrent diseases, like pneumonia. But 
or.e thing can be said already as based on experience. Man’s life of activity, 
that part of man’s life where he works and creates, can be prolonged in 
many instances. This, it seems is the important fact. A warning should be 
sounded against too great an enthusiasm and against raising too many hopes. 
Steinach’s own words should be remembered, “That within modest limits the 
process of becoming senile can be influenced.” It will be a matter of future 
study to determine its exact value to the individual and to society in all its 
economic and social consequences. , 
Relationship to Other Endocrine Glands 
An intimate relationship exists between many of the sexual secretions and 
the hormones elaborated by some of the other ductless glands. As an example, 
the adrenals have an intimate relation with the ovaries and testes. Lesion of 
the suprarenal cortex, leading to increased secretions, turns the secondary 
characteristics of a female in any given case into those of a male and sup- 
presses the functions of the ovaries. It is only logical to suppose that the 
suprarenal cortex when normal had been feminine rather than masculine in 
type (Bell). Abundant evidence shows that a large number of internal secre- 
tions are concerned in the development of the sexual glands, for sexual pre- 
60 cocity can be associated with tumors of the adrenals, as above, and with dis- 
turbances in the hormonic balance (Cobb). It is a fair assumption, therefore, 
that there may exist gonadal stimulating properties in some of the other 
endocrine glands. 
Influence on Metabolism 
The influence of the internal secretion of the testes is to be noted in, con- 
nection with the growth and general metabolism of the individual. At puberty 
and during the breeding season in the lower animals, there is a marked increase 
in the vitality and the metabolic activity of the animal. We have an increase 
of vigor both physical and psychical. An increase of the interstitial cells 
occurs. On the other hand diminution of the functions of the interstitial gland, 
tor any cause whatever, is accompanied by senile changes very similar to 
those resulting from castration. From this we may infer that the interstitial 
hormone directly influences the increased metabolic rate common at puberty. 
E. Allen has shown that the interstitial tissue of albino rats fed on a 
diet deficient in water soluble vitamines, is hypertrophied. A concomitant 
result is that these animals become sterile. This condition is analogous to the 
results following exposure of the testes to X-rays. 
Normal growth and development of osseous structures is intimately as- 
sociated with the elaboration of an internal secretion by the testes. Following 
castration endochondral ossification is stimulated and prolonged. The skull 
is altered with the result that the cranial capacity develops less completely 
than is normal. The expansion of the antrum of Highmore is retarded, as 
the result of which the face remains narrow. Steinach’s experiments showed 
that “feminized’ rats possessed a female form of pelvis. The reverse is true 
of “masculinized” animals. The fact that gonadectomy is frequently followed 
by an increased deposition of fat shows that there must be an intimate relation 
between fat metabolism and the testes. Such a deposition is also true in men 
and women of advanced age after the supression of sexual activities. 
The phenomenon of sex intergrades contradicts the older conception that 
sex is an absolute attribute. Sex intergrades may be established experimentally 
in animals by the simultaneous implantation of gonadal tissue into previously 
castrated animals. These experiments were performed by Sand, Steinach and 
Boruttan. If the reproductive tissue of the two sexes were simultaneously 
implanted in a neutral animal, the interstitial tissue of both sexes intermingled 
in their growth and produced hormones. This resulted in the development of 
male secondary sex characteristics, the skeletal and muscular growth also 
being that of a male. Psychically, the individual behaves at times as a male, 
and at times as a female. As a male it will fight off other males, and seek 
and attempt to mate with rutting females. At cyclic intervals it behaves as a 
female and will be sought and courted by males. If, however, male interstitial 
tissue predominates, male characteristics will predominate, and vice versa. 
According to Biedl, it appears as though the gonadal hormones are not an- 
tagonistic, but exert their influence in proportion to the degree and quantity of 
their delivery to the somatoplasm. Goldschmidt contends that no animal 
including the human is either purely male or female, but that each has the 
potentialities of both. In the light of modern experimental proof, herma- 
phrodites and pseudohermaphrodites, and many other persons considered 
SeX-Intergrades 
61 abnormal, should be considered as intergrades. These cases, therefore, are 
not pathological, but simply natural variations, the result of the chromosome 
complex, and of abnormal internal secretion of the gonads. Normal sex must 
be considered as the result of complete differentiation of the sex gland anlage 
into one or the other type of interstitial cells. 
Based upon the evidence we have collected we believe that the following 
conclusions may be safely drawn. It appears certain that the internal secre- 
tion of the testis definitely influences somatic growth and stimulates the de- 
velopment of the secondary sex characteristics. 
BIBLIOGRAPHY 
Barker, L. F.: Endrocrinology and Metabolism, 1922. 
Bell, Dr. Blair: Part Played by the Endocrine Glands in Evolution. Lancet, vol. 2, 
p. 588, Dec. 4, 1920. 
Bolk, Prof. L.: Vol. 2, p. 588, Jan. 29, 1921. 
Benjamin: N. Y. M. J., 114: 687, Dec. 21; 112:848, Nov. 27, 1920. Sterility, Sex 
Stimulation and Endocrines. 
Biedl, A.: Internal Secretory Organs. 
Blumgarten, A. S.: Role of Endocrine System in Internal Medicine. N. Y. M. J., 
1921, cxiii, 233-239. 
Bolognesi: J. A. M. A., vol. 77, 1926. 
Brock, S. & W. E. Kay: Study of Unusual Endocrine Distribution, etc. Arch. 
Inst. Med. Chi., 1921, xxvii, 1-27. 
Cobb: Organ of Internal Secretion, pp. 190-211. 
Cunningham, J. F.: Hormones and Heredity. 
Endocrinology: Vol. 5, No. 3, “Testes Vasectomy.” 
Endocrinology: Vol. 5, No. 2, Kuntz; Degenerative Changes in Seminal Epithelium, 
as associated with hyperplasia of interstitial tissue in mammals. 
Hammer, J. A.: Surg. Gynec. & Obst. Chic., 1921, xxxii, 205-209. 
Humphrey: Interstitial Cells of Urodele Testis. Amer. Jour. Anat., vol. 29, No. 2, 
1921. 
Ishubase. Mitt. A. D. Med. Facultat., 39, Aug. 29. 
Journal A. M. A., vol. 77:1926. Transplantation of Testes. 
Journal New York Medical, 20:379, Sept. 1920. Disturbances of Endocrine Function 
of Gonads. 
Kaplan, D. N.: Endocrine Tropisms. N. Y. M. J., 1921, cxiv, 26-31. 
Kendall, E. x\.: Chemical Influence of Active Constituents of Ductless Glands. 
Loeb: Transplantation and Individuality. Biol. Bull., vol. 40, No. 3. 
Lydston, G. F.: Two Remarkable Cases of Testicle Implantation. McKenna, Illinois 
M. J., Chicago. 
Massaglia. A. C.: Internal Secretion of Testis. Endocrinology, vol. 4, 
Meyer, R.: J. A. M. A., vol. 76, 1866. 
Roniees, Dr.: Internal Secretion of Testes. Endocrinology, vol. 4, p. 257. 
Sand, Dr. Knut: Internal Secretions of Sex Glands, Jour. Physiol., 53:257, Dec. ’20 
Sank, K.: Experimental Hermaphroditism. Jour. Physiol., 53, pp. 257-263. 
Sayons: Endocrines in Everyday Practice. N. Y. Med. Jour., cxiv, 20-26, 1921. 
Stanley: J. A. M. A., Aso. Chicago, xxiv, 1501-1503, 1920. 
Steinac.h, Dr.: Verjungering. 
Stanley: Testicular Substance Implantation. Endocrinology, May 1921. 
Tarbett: Practical Points in Endocrinology with Illustrative Cases. Med. Records 
N. Y„ May 1921, 99:866. 
Torbett, J. W.: Med. Record N. Y., 1921, xcix, 866-868. 
Vincent, S.: Internal Secretion and Ductless Glands, pp. 67-75. 
Whitehead: .American Journal Anat., vol. 14—1912, pp. 63-71. 
Whitehead: Anat. Rec. 1908, vol. 2, pp. 177-182. 
Pubertv Climacterium. Med. Clinic of North America, 4:59, July 1920. 
Interstitial Cells, Testes of Albino Rat. Anatomical Record, vol. 20, No. 4, March ’20. 
62 THE REACTION OF LIVING CELLS TO FOREIGN 
BODIES 
THE reaction of living cells to foreign bodies involves practically the 
whole of medicine. Naturally, in less than half an hour, we can consider 
only a small phase of the question. We shall not touch upon macroscopic 
foreign bodies such as splinters, bullets and safety-pins. Nor shall we con- 
sider food in the digestive tract. This paper will have to be limited to the 
finer reaction that takes place when certain microscopic substances and their 
toxins attack the living cell. Bacteria, however, are not going to be con- 
sidered. Instead, we are going to give a survey of some recent experiments 
on the injection of different substances such as proteins, fats, erythrocytes, and 
various oils into living animals. The animal body is, as we have all learned, 
an accumulation of myriads of cells all working together. During years of 
evolution, these entities have developed a very effective protective mechanism. 
Various phases of this mechanism we are just beginning to understand. In 
the normal individual, everything is in equilibrium. When extraneous mat- 
ter is introduced this equilibrium is upset. To restore it the body may form 
antibodies which neutralize the toxic effect of the foreign substance, or the 
body may send its phagocytes to ingest the foreign substance. 
The study of the reactions of living cells to foreign bodies arouses 
interest in the relation of these cells to antigens and antibodies as contrasted 
with their reaction to non-antigens. It is, therefore, the purpose of this 
article firstly—to briefly review the nature of antigens, secondly—to present 
a series of experiments which tend to show their influence on antibody for- 
mation, and finally to observe the reactions of living cells to various diverse 
types of nonantigenetic substances. 
When we look at the question from the chemical viewpoint, we note 
that there appears to be an essential difference between the reactions which 
are induced by simple chemical compounds and those which are incited by 
more complex substances of a protein nature. This latter group of sub- 
stances incite reactions which are more or less specific in nature and which 
increase the resistance of the body against the substance that has induced 
the reaction. On the other hand, the non-proteins are involved in reactions 
which are not specific and which do not increase the defensive powers of 
the body so as to give it an immunity against the poison. The substances of 
the first group are non-antigenetic, while those of the second (more complex) 
group are antigenetic. By antigens we mean substances that are capable of 
causing the formation of specific antibodies which will react with the antigens. 
In general only proteins will produce antigens, although there are cases on 
record of other substances doing this. Not all proteins, however, will induce 
the formation of antigens. The derived proteins are deficient in this respect. 
Solubility of the protein seems to be necessary, as proteins which have been 
coagulated by heat lose their antigenetic properties. Non-coaguable proteins 
even after boiling retain their antigenetic nature. 
63 It was formerly believed th„t the introduction of a protein into the body 
caused the formation of enzymes which destroyed and removed the foreign 
protein and that the excess of enzymes produced were the antibodies that 
gave an immunity. This theory has been accepted in part but with this 
modification : that it is the destruction of the foreign material which causes 
the antibodies to be produced in excess. In support of this view we have 
a number of investigations which show that the more readily a protein is 
broken down by proteolytic enzymes, the more easily will antibodies be 
formed. Gelatin is, however, an important exception to this rule, for although 
it may readily be disintegrated by enzymes, it fails to react as an antigen. 
In establishing this general theory the work of Ten Broeck has been most 
striking. He has proved that racemized protein, which in every w?A 
resembles simple protein save that it lacks optical activity and resists or- 
dinary digestion, is non-antigentic in nature. Upon treating a sensitized 
guinea pig with racemized egg albumin no symptoms of anaphylaxis were 
noted. Treating a control animal with the same dose of ordinary egg 
albumin death was produced within two hours. 
Attempts have been made for a long time to arrive at the composition 
of the antigens and antibodies. They were formerly considered of a protein 
nature. Recent workers who have obtained them in a greater state of purity 
report that they fail to respond to the protein tests. Warden since 1915 has 
spent much time on this subject. He has attempted to show that the specific 
antigens are fatty complexes which are peculiar to a particular protein and 
which serve to give it a definite chemical character. Thus its specificity 
depends upon the composition of the fatty acids which make it up end on 
the kind of surface which receives it. In this way we may conceive of an 
infinite number of antigens. Perhaps the most convincing of his experiments 
has been that on the antigen of anthrax. From cultures of this bacillus he 
was able to obtain sufficient fat to make an analysis. He discovered it con- 
tained caprylic, caproic, palmitic and oleic acids. About a half of the mix- 
ture appeared to be oleic acid. By trial mixtures, he found that one which 
contained 10% caprylic, 25% caproic, 5% palmite and 60% oleic gave im- 
munity reactions which most closely approached those which resulted from 
the bacillus itself. Upon injecting protective amounts of this synthetic anti- 
gent into rabbits he has been able to make them withstand ten times the lethal 
dose of the bacteria. He has failed, however, with a hundredfold dose. As 
he did not need any protein from the anthrax bacillus to establish this im- 
munity he concludes that aside from emulsifying power protein has little 
function in immuni y react'.ons. He accounts for his difficulties in preparing 
very powerful artificial antigens as the result of his inability to determine the 
exact composition of the antigen and the best method of dispersing it. 
Many interesting experiments have been carried out in an attempt to 
discover the relation of these antigens and antibodies to the tissues. One of 
the latest theories is to give most of the credit for destroying an.igens and 
forming antibodies to that mysterious organ—the spleen. The experiments 
to be described here are the ones in which foreign blood cells were used as 
the antigens. 
In 1911 Luckhardt and Becht carried out an experiment on dogs from 
which they reached two main conclusions: 1, that the spleen hxes antigen, 
and 2, that the spleen is concerned directly or indirectly in the production 
of immune bodies (antibodies). These authors assumed that foreign erythro- 
64 cytes are hemolyzed in the blood of the animal injected and that the spleen 
cells help remove them. They reasoned thus—one of the functions of the 
spleen is to destroy the worn-out red blood corpuscles of an organism. 
Why, therefore, would it not destroy foreign corpuscles injected into the 
blood stream? Since these injected corpuscles would be foreign to the 
organism, the spleen would react against these corpuscular antigens by pro- 
ducing great numbers of specific destructive agents (the antibodies in ques- 
tion). 
Their method was to inject an optimum dose of goat’s or rat’s blood 
corpuscles (the antigen) into a dog’s veins. When they removed the spleen 
of this dog, emulsified it and introduced it into the peritoneal cavity of a 
normal dog, they found the specific immune bodies in the serum of the latter. 
Evidently the spleen of the injected dog had formed excess immune bodies. 
The introduction of normal spleen into the peritoneal cavity is not followed 
by an increase of antibodies in the serum of the recipient. The introduction 
of any other tissues from the injected animal, whether heart, liver, bone 
marrow or lymph glands, did not give positive results. That is, only in- 
jections of the spleen of the injected dog could immunize a normal dog to the 
substance injected. 
To verify, they also performed experiments on dogs without spleens and 
compared their reactions to the reactions of the normal dogs. The asplenic 
dogs did not produce immune bodies as rapidly or in so high a concentration 
as the control dogs. 
What cells in the spleen, the fixed or wandering cells, possess this 
power ? 
In 1915 Cary, working on rabbits, claimed to have shown that the de- 
struction of an animal’s own red blood corpuscles is accomplished by special- 
ized fixed tissue phagocytes (the endothelial and reticular cells) in liver and 
spleen. Cary called these fixed phagocytes hemophages. He further con- 
cluded that this hemophage activity increases directly with the number of 
erythrocytes injected and with the length of time these foreign corpuscles 
are allowed to stay in the rabbit’s blood before the animal is killed. 
Cary used washed beef corpuscles as the antigen and observed their 
effects in the blood stream of the rabbit. Normally there are not any active 
hemophages in the liver; the hemophages in the spleen are sufficient to 
destroy the erythrocytes. The ingestion of red blood cells by hemophages 
was indicated by a positive iron test showing that hemoglobin was present. 
Cary injected foreign corpuscles to see whether they or their products would 
also be ingested by the hemophages. As he expected, the hemophages of 
the spleen and also of the liver attacked the foreign corpuscles. Because 
liver and spleen endothelial and recticular cells gave a prussian blue positive 
iron test after foreign red blood cells had been injected, Cary concluded that 
the fixed cells could destroy antigens. 
Cary, in concluding, went a step further than Luckhardt and Becht. 
Working on the known principle that' foreign red blood cells introduced into 
an animal stimulate the production of specific antibodies, he proposed to 
show in a. later article that the very cells which destroy erythrocytes help 
form their antibodies. Unfortunately, he has not as yet published such an 
article. But the work of Luckhardt and Becht and the work of Williams 
tend toward such a conclusion. 
Williams, in his report, 1919-20, claims that the fixed tissue cells should 
65 not get all the credit for destroying antigens, because the same cell types are 
not the active phagocytic agents in all cases. As he phrases it, “In some 
conditions, it is found that fixed cells, such as reticular and endothelial cells, 
are most active, while in other conditions, free cells, such as splenocytes, 
are the most predominant phagocytic cell type. These findings are to be 
correlated with the well recognized fact that the phagocytic cells have a 
selective action, some types reacting to one stimulus, some to another.” Wil- 
liams, is, of course, referring to the large, free-swimming mononuclears, 
which he terms splenocytes, normally found in the spleen. Though these 
may ultimately be derived from the endothelial cells (P. & S. Students’ Re- 
port, 1921), Williams’ technique (better than Cary’s) indicates that where 
cells and cell fragments, erythrocytes in particular, are concerned, the spleno- 
cytes (free cells) are the first to act and they continue to act as the main 
phagocytic agents. 
The stimulus employed in his experiment was washed pigeon corpuscles 
injected into the circulation of the rabbit. He found that rapid destruction 
(hemolysis) of the foreign corpuscles ensued and, as an almost immediate 
effect, was followed by the release of mature and immature blood cells 
(including polymorphonuclears and myelocytes) from the bone marrow. Both 
the hemolyzing blood of the pigeon and the bone marrow cells of the rabbit, 
being brought by the circulating blood to the spleen and then delayed within 
the cavernous blood channels of the pulp, were thus exposed to the phagocytic 
action of the splenic cells. 
Williams interprets the “bone marrow crisis” as he terms it, to be the 
result of the toxic material set free in the hemolysis of the pigeon blood. 
In the spleen he found that the bone marrow cells were ingested by the 
splenocytes which grew larger with their contents and showed, in some in- 
stances, as many as twenty cells in one focal plane. Towards the end of 
digestion of their inclusions the splenocytes returned to normal size. He also 
found that the endothelial cells as such were little concerned in phagocytic 
activity in this experiment, as determined by the iron test, miscroscopic ex- 
amination, etc. 
Keeping the results of these experiments in mind, it is possible to reach 
the general suggestive, if not positive conclusion with Cary, that the cells 
which destroy erythrocytes participate in the formation of their antibodies, 
especially when we consider the possible significance of the bone marrow 
crisis in Williams’ experiment. 
Independent of but coordinated with this method of attack is the more 
general method explained on physico-chemical grounds, surface tension, etc., 
of the invader attracting hosts of protecting bodies, especially leucocytes. 
As you know, phogocytosis is not concerned alone with destroying dead cells, 
hut may go on in any tissue. Now we are going to look at phogocytosis as 
a general fight against foreign stimuli. 
A new method of aproach to this problem has been suggested by Eleanor 
and Eliot Clark. For 12 years these experimenters have been studying the 
reaction of connective tissue cells, wandering cells, and lymphatic and vascular 
endothelium in the tadpole’s tail towards various injected substances. These 
Clark experiments are very important for they furnish us with accurate 
records (drawings were made with the aid of a camera lucida) of the re- 
actions of living cells in the transparent fins of the tadpole’s tail. The Clarks 
chose normal larvae, anaesthetized them in chloretone solution, with fine 
66 glass needles injected various foreign substances into their tail fins, and kept 
the tadpoles under continuous observation for hours, days or weeks depend- 
ing on the experiment. 
Their results show that different cells respond differently to varying 
stimuli. Though all of the four types studied orginally were of mesenchymal 
origin, yet when differentiated into endothelium, leucocytes and connective 
tissue cells each type has a specific reaction and each cell remains specific. 
In all their work they never found any evidence of one type of cell changing 
into another type of cell. Several times they noted cases of apparent change, 
but continued observation proved there never was any real change. Each cell 
when once differentiated remained specific, no matter what stimuli were 
present. 
For successful experiments on tadpoles’ fins the substances must he 
readily injected through small glass cannulae which cause a minimum of 
injury, and the substances must remain unabsorbed long enough to be ob- 
served. The substances used were suspensions of carbon and carmine gran- 
ules, droplets of an inert oil (paraffin), nutritive oils (fatty oils), aseptic 
oil, starch granules and similar substances in varying forms. These varying 
substances called forth varying responses among the several types of cells. 
Connective tissue cells took up carbon and carmine granules and pha- 
gocytized them, hut connective tissue cells did not touch starch or fat. These 
cells showed varying degrees of injury when an aseptic oil was injected. 
Lymphatic endothelium grew towards fatty substances, but not towards 
starch grains. 
Leucocytes responded with varying intensity to different substances. 
Their response to paraffin oil was no greater than their response to the 
injection needle. A few wandering cells appeared, then left the spot. Car- 
bon, carmine and uncooked starch did not have much more effect. They 
attracted wandering cells and an hour or two later some leucocytes came from 
the nearby blood vessels and began to phagocytize the granules which re- 
mained as cell inclusions indefinitely. The control reaction to small glass 
tubes was very similar. 
Fatty substances attracted more leucocytes. Clear leucocytes came to 
globules, ingested them, wandered to the lymphatics full of granules of fat, 
discharged them in soluble form into the lymphatics and came away clear. 
The rate of attraction for leucocytes depends upon the fineness of physical 
state. Fine emulsions of egg yolk and cream’ were most rapidly absorbed, 
dissolved and carried to the lymphatics. Olive oil globules were much more 
slowly absorbed by leucocytes. Lymphatic capillaries sent snrouts to them. 
This growth of lymphatic capillaries was especially noticeable in the case 
of slowly absorbed granules. With the fine emulsions, leucocytes acted before 
the lymphatics had shown much response. Feissinger and Marie claim to 
have discovered a lipase in lymphocytes and a protein-splitting enzyme in 
polymorphonuclears. The Clarks believe this conclusion may be borne out 
by the fact that often leucocytes near the fat remained unaffected, while 
others further away moved towards the fat. The experiments with fat have 
an additional interest in connection with the much debated ouestion of fat 
absorption in the body. Why couldn’t the leucocvtes in the intestine absorb 
some fat and take it to the lymphatics? In the tadpole’s fin the fat globules 
attracted or were positively chemotatic to lymphatic endothelium and to some 
leucocytes, presumably to the lypmhocytes. 
67 When a microinflamation was caused by the injection of croton oil an 
extremely interesting reaction followed. All the cells in the region showed 
signs of injury. Due to granulations in epidermal and connective tissue cells, 
an opaque zone extended around the oil globule. All endothelial and con- 
nective tissue cells became swollen, and vacuolated, and the nuclei became 
very distinct. In addition connective tissue cells lost their processes and 
became shadowy, lymphaic sprouts within the zone were retracted and blood 
capillaries within the zone suffered from hemorrhage. In the blood vessels 
without the zone quickened flow was taking place and diapedesis. These 
leucocytes came to help the wandering cells of the neighborhood which had 
at once rushed to the injury. Leucocytes came from rather distant blood 
vessels to the site of injury. What interested us most was the almost un- 
canny way in which the leucocytes seized the shortest cuts to the injury, 
dodging connective tissue cells, and anything else in their way. Qute a 
number slipped into nearby lymphatics, slid to the tip, and then crawled out. 
They formed a sessile circle a little distance form the globules and sent out 
processes at first fine and transitory, but which soon became thicker and 
permanent, until the leucocytes resembled fibroblasts or connective tissue 
cells. This circle evidently localized the infection, because cells distal to it 
recovered at once. A different kind of leucocyte than is found in humans, 
the pigmented leucocyte, a very resistant type, next came upon the scene and 
boldly went up to the injection mass, actually flattening out against it. Soon 
there was such an accumulation of fluid at the spot that the injurious mass 
was forced out. As soon as the stuff was extruded, the tissue healed and 
the pigmented leucocytes wandered away. The clear leucocytes lost their 
processes, rounded up and finally, with regained amoeboid movement, wan- 
dered off. Connective tissue cells, stellate once more, came in to fill the gap 
where the oil had been. Within two days circulation was normal. 
In their latest set of experiments (Oct., 1922), the Clarks worked with 
polysaccharids. They found so much difficulty in forcing grains and agar 
agar, etc., through the injection needles, that they tucked the needle into the 
skin, broke off the tip and left a small test tube open at the ends of the fin. 
The reaction caused by the needle was transitory and by the use of control 
experiments could be discounted. The reactions of the substances in the tube 
could be readily noted. 
In many larvae tubes of cooked starch were injected into one fin, and 
tubes of uncooked starch were injected into the other. Leucocytes wandered 
to both, but many more leucocytes wandered to the cooked. Leucocytes filled 
the lumen of the cooked and all of the starch was inside the leucocytes. In 
the case of the uncooked, a few entered the lumen of the tube and ingested 
the refractile granules. In a week or ten days the tube was extruded. Some 
leucocytes with refractile granules still remained in the original situ, others 
wandered around in the nearby tissues still with refractile granules unchanged. 
Probably the cellulose covering prevented the action of the enzymes in leuco- 
cytes and lymph from attacking the granules which remained as cell inclu- 
sions (like carbon or paraffin). 
In some experiments boiled starch alone was injected. In one case three 
granules were injected. In ten minutes they were but shadows. In sixteen 
minutes they had completely disappeared. An iodine stain showed a diffuse 
blue where the granules had been. Here the starch had dissolved before 
the tissue cells were visibly affected and before any leucocytes reached the 
68 spot. Evidently tissue fluid is capable of dissolving and digesting cooked 
starch grains. Where more granules were injected, leucocytes aided the 
tissue fluids. Such a specimen stained with iodine showed two large blue 
granules with leucocytes about to engulf them, a finely granular blue stain 
and several leucocytes wi:h bluish cytoplasm. An hour later no trace of 
blue was visible on staining with iodine. 
Another set of experiments with gelatinized or semi-cooked starch called 
forth the most violent response of leucocytes. No other substance caused so 
many leucocytes to respond or to respond so quickly. The leucocytes rushed 
from the nearest blood vessels. Where semi-cooked starch had been was 
within fifteen minutes a dense mass of leucocytes. In one experiment, four 
semi and six completely cooked granules were injected. The leucocytes made 
a bee line for the former, actually passing between two cooked granules to 
reach a semi-cooked. Meanwhile the cooked granules became shadowy. As 
soon as the semi-cooked were disposed of, the leucocytes attacked the rem- 
nants cf the cooked starch and finished digesting them. Fixed snecimens 
showed that both polymorphonuclears and mononuclears were attracted by the 
starch. Iodine staining showed semi-cooked starch is ingested and dissolved 
by leucocytes (diffuse blue) and after three hours is changed to another 
substance, probably a colorless dextrin or sugar. (Tests to prove the presence 
of sugar were not successful. But this is not so significant, since injected 
solutions of dextrin gave negative sugar tests.) The experimenters compared 
the fate of the starch injected subcutaneously with the fate of starch treated 
with ptyalin and found that the tissue fluids acted more slowly and probably 
formed a colorless dextrin. 
With agar agar, celloidin and gelatine, the leucocyte reaction is similar 
in intensity to that caused by the semi-cooked starch. As with s arch, these 
colloids caused no response of connective tissue cells or of endothelium. 
In all these experiments we saw how different cells phagocytized different 
foreign bodies. Usually the leucocytes were the most active phagocytes. Why 
the phagocytes should be attracted to the foreign body has proved a very 
baffling problem. The present trend of opinion is to regard it is a result of 
surface tension. In ’90, Grabitchewsky classified substances as positively, 
negatively or indifferently chemotatic to leucocytes. Positively chemotatic 
substances being those which lowered the surface tension of the cell, Causing 
the cytoplasm to flow toward them. In ’21 Fenn worked out by calculus, 
physics, etc., the degree of intensity of attraction of various substances. He 
concluded it was a surface tension phenomenon. When he studied the reaction 
of leucocytes to quartz and carbon, he found that the carbon was phagocytized 
three or four times more rapidly than the quartz. Fenn. claimed that thn 
difference in rate was due to the more unstable condition of the carbon 
suspensions. A number of experimenters claim that they can duplicate all 
the ordinary phenomena which we may note in phagocytosis with a drop of 
chloroform in water, and they ascribe them all to surface tension. It seems 
as though we have no alternative but to accept some sort of physical explana- 
tion like this. Should we refuse we must then endow each individual 
phagocyte with reasoning powers that wofflvd do honor to any man. 
Just as some philosophers would reduce each human being to a mechanical 
entity and explain all our actions by laws of physics and mechanics, while 
others see in each human being a miniature god, so in phagocytosis, one set 
of experimenters would endow each phagocyte with almost human psychic 
69 powers of selective working—while others would reduce their whole action 
to the physical laws of tension. 
Even as a few centuries ago, the development of that simple instrument, 
the telescope, brought far distant units of the universe to our ken, so with 
the intelligent use of labroatory technique, especially the microscope, within 
the last few decades, experimental biology has brought to our comprehension 
the equally distant and unknown universe of the actions and reactions of the 
cells of the body. 
In the same way as physical laws, such as gravitation, explain nearly all 
the laws of the stellar universe, it is apparent more and more that physico- 
chemical laws, such as surface tension, explain most of the reactions of the 
foreign bodies to this cellular universe. 
BIBLIOGRAPHY 
Addison, W. F.: Histologic study of rabbit’s spleen under heightened phagocytic 
activity. Jour. Anat., No. 26, 1919-20, p. 437. 
( a-y, W. E.: Fate of fo-eign cry'.hrof'vtes int”oduced into the blood stream of a 
rabbit. Jour. Inf. Dis. vol. 17, p. 432, 1915. 
Clark, E. R.: Further observations on living growing lymphatics. Araer. Jour. 
Anat., 1912. vol. 13, p. 351. 
Clark, E. R.: Study of reaction of mesenchyme cells in tadpole’s tail toward in- 
jected oil globules. Amer. Jour. Anat. 13, p. 351, 1916. 
Clark, E. R. and E. L.: Study of reaction of lymphatic endothelium and of leu- 
cocytes in tadpole’s tail toward injected fat. Amer. Jour. Anat. 21, p. 421, 1917. 
Clark, E. R. &• E. L.: Reactions of cells in tail of Amphibian Larvae to injected 
croton oil. Amer. Jour. Anat. 27, p. 221, 1920. 
Dakin & Dudley: Racemization of proteins. Jour. Bio. Chem. 15, p. 263, 1913. 
Dakin & Dudley: Racemized protein not digestible by enzymes. Jour. Bio. Chem. 
17, p. 369, 1914. 
Fenn, W. O.: Phagocytosis of solid particles. Jour. Gen. Physiology, 3, p. 575. 
Luckhardt, A. B. & F. C. Becht: Relation of the spleen to the fixation of antigens 
and the production of immune bodies. Amer. Jour Physiol., 28, p. 5, 1911. 
Paton, D. N. & A. Goodall: The spleen in relation to the process of hemolysis. 
Jour. Physiol., 29, p. 411, 1903. 
Rons, P. & O. H. Robertson: Normal fate of erythrocytes. Jour. Exp. Med., 25, p. 
65’, 1917. 
Ten Broeck: Racemized protein does not cause anaphylaxis. Jour. Bio. Chem., 17, 
p. 369, 1914. 
Warden: Role of specific fats in the complement fixation. Jour. Inf. Dis., 22, 
p. 133, 1918. 
Warden: Specific fats as factors in immune processes. Jour. Inf. Dis., 24, p. 285, 
1919. 
Warden: Antigen of Bacillus Anth--acis. Jour. Inf. Dis., 25, p. 399, 1919. 
Wells, II. G.: Chemical pathology, 1918. W. II. Saunders. 
Wolf, E.: Influence of chemicals upon chemotaxis of leucocytes in vitro. Jour. 
Exp. Med.. 35, p. 375,- 1921. 
70 THE EVOLUTIONARY SIGNIFICANCE OF 
VARIATION 
EVOLUTION signifies a state of becoming. It does not necessarily imply 
that species have been getting better and better through the ages but 
rather that in accordance with the ‘ Law of Adaptive Radiation” they 
have been modified to meet the demands of their changing environment. Al- 
though little more than half a century has passed since the publication of the 
“Origin of Species” there has been welded a chain of evidence so complete 
that to-day few things in natural history have been more firmly established 
than the fact of evolution. 
Students of comparative anatomy have shown the relationship between 
various groups of organisms and have clearly pointed out that structures which 
at first glance seem to be totally different are fundamentally the same. For 
example, if the foreleg of a lizard, the wing of a bird, the wing of a bat, 
the flipper of a whale and the human arm be carefully dissected, and the 
bones, muscles, vessels and nerves compared it will be found that the plan 
of structure is the same throughout and is merely modified in each case 
according to the use to which the part is put. 
The paleontologists have examined the fossils of the plants and animals 
entombed in the rocks of the earth’s crust and have dug up some of the most 
convincing proof of evolution. They have found that the oldest portions ot 
the earth’s crust are devoid of fossil remains. Either there were no living 
organisms or else they were of such simple structure that they left no record. 
The next geological era, the palaeozoic, marks not onlv the rapid development 
of the invertebrates but also the rise of the more primitive back-boned animals. 
This is followed by the mesozoic, the golden age of reptiles. Before the end 
of this era the primitive bird and first mammal have appeared. The cenozoic 
brings with it the high development of birds and mammals. The primates arise 
and finally man appears. Layer by layer the fossils tell the story of a grad- 
ual development from the simple to the complex. 
The evidence offered by the embryologists is no less significant. Flaeckel 
has summarized the contribution in his biogenetic law, namely, that the in- 
dividual in his development recapitulates the history of the race. It must be 
remembered, however, that this history is greatly abridged. Structures are 
found in the human embryo which are typical in lower forms. These are 
transitory and are later either lost or greatly modified. In some instances, 
however, they remain and are found in the adult as vestiges. At a certain stage 
in the development of the human embryo gill-pouches are present. There is 
a two-chambered heart and a fish-like circulatory system. At a later stage 
the gill-pouches are obliterated with the exception of one which is converted 
into the Eustachian tube. The embryo of the whale has a dense covering of 
hair which is later lost, only a few coarse bristles persisting on certain parts 
of the adult body. 
The geological distribution of animals and plants over the surface of 
the globe first turned the thoughts of Darwin towards evolution. All of the 
71 evidence goes to show that each species has originated in a particular area 
and has spread from that point. In general, the longer the time any two 
regions have been separated, the greater is the difference between their flora 
and fauna. Thus the separation of Great Britain from the Continent took 
place in comparatively recent times and the animals found in both places are 
very similar. On the other hand, areas like Australia that have been isolated 
for a long time have their own peculiar species. On the island-continent are 
found the egg-laying mammals and nearly all of the known marsupials. 
The latest link in the strong chain of evidence has been contributed by 
the serologists. A number of workers, notably Dr. George H. F. Nuttall, have 
shown that by means of the precipitation test the relationship among animals 
can be clearly demonstrated. Their results have checked up with those of the 
comparative anatomists and paleontologists. For example they have found 
that if the sera of the various apes be titrated against an anti-human serum, 
a good precipitate will be obtained with that of the higher anthropoids, a 
very slight one with that of the New World monkeys and none at all with 
that of the lemurs. The fact that apes are susceptible to human diseases 
further indicates a blood relationship. 
The primary factor in evolution is obviously variation. Were no changes 
to occur, movement in one direction or another would be impossible. 
The two main problems associated with variations are: 
(A) The origin of variations, and 
(B) The mechanism of their transmission. 
At the outset we must recognize the fact that there are different kinds of 
variations. Some of them cannot be transmitted from parent to offspring and 
therefore play no part in the process of evolution. 
We may classify all variations under two general headings: 
1. Congenital. A better term would be “blastogenic,” which signifies 
“present in the germ plasm.” This type of variation is therefore intrinsic 
in the individual and is presumably not due to any external influence. It may 
appear, however, at any time from the beginning of embryonic existence to 
the death of the organism. 
2. Acquired. In contrast to the preceding there are variations which are 
definitely extrinsic in nature and which are the result of external influences 
upon the organism. These, in as much as they are not inherent in the germ 
plasm, cannot be inherited by the offspring. 
The last statement is accordance with the opinion of the vast majority of 
biologists. 
It is important to remember that characters may be acquired “in utero” 
and that these are not necessarily congenital. An example of a congenital 
variation is the occasional occurrence of supernumerary digits in man. On 
the other hand the loss of a digit through amputation illustrates a variation 
that is acquired and therefore has no significance in race-history. 
The group of congenital variations may be further divided into two 
classes: 
a. Continuous. These are small, numerous and occur in a graded series. 
The increment of change between successive generations is extremely slight. 
Darwin called them “fluctuations” and thought that it was through the action 
of the Law of Natural Selection upon them that evolution bad come about. 
Some workers, notably Prof. Karl Pearson, have applied the laws of mathe- 
matics to the study of the occurrence of variations. They have shown that 
72 if a certain character, as height in man, be examined in a great many individ- 
uals and a curve plotted, it would conform very closely to the mathematical 
curve of probabilities. Over 4,OCX) individuals were examined and their meas- 
urements recorded by the Cambridge Anthropometric Society. A symmetrical 
curve was obtained and the numbers of departures from the normal, which 
in this case was found to be 69 inches, was the same in both directions. For 
example the number of men 67 inches in height equalled the number of men 
71 inches. 
b. Discontinuous. These are also known as “sports” or “mutations.” 
They represent differences of great amplitude and, compared to the other 
type of variations, occur rarely. One of the classical examples is that of the 
short-legged ram which suddenly appeared on a farm in Massachusetts and 
which gave rise to the so-called Ancon breed of sheep. 
Galton explains the formation of a mutant by comparing it to a polygon 
that changes its base. If the new bases becomes the one represented by the 
lMgure i. 
line B-C it is unstable and will soon return to the old base. This would 
represent the ordinary continuous variation. If, however, a sudden force 
pushes it over to the base C-D ft becomes a new form which is stable and 
which will not revert. This would correspond to a mutation. 
De Vries divided mutations into three classes: 
1. Progressive. The appearance of new characters. The character when 
first formed may be latent and may not appear in the individual for a number 
of generations. 
2. Degressive. A sudden change from latency to activity. 
3. Retrogressive. The converse of degressive. An active character that 
has suddenly become lost. 
Jennings, after very careful work chiefly with animals that arise from a 
single parent, has attacked the conclusions of the mutationists. He claims 
that minute heritable variations—so minute as to represent practically con- 
tinuous gradations—occur in many organisms and that these have been over- 
looked by the mutationists. These numerous small variations, he states, are 
acted upon by Natural Selection in accordance with the typical Darwinian 
scheme. 
A. The question as to the origin of variations is by no means settled. 
The answer at best is a matter of speculation. The three principal explana- 
tions that have been offered are: (1) Inherent tendency; (2) Amphimixis; 
and (3) Mutations. 
1. Inherent Tendency. Some believe that there exists in the germ plasm 
a force which causes it to constantly vary, thus bringing about variations. 
These may be fortuitous, fluctuating or follow certain fixed lines. 
73 2. Amphimixis, or biparental parentage. The union of the traits of 
two lines of ancestry makes possible different combinations of characters. 
This principle which is advocated by Weissmann, may explain how recessive 
characters appear but leaves unexplained the origin of characters that never 
before have been present in the germ plasm. 
3. Mutations. The sudden appearance of new types through a rearrange- 
ment of the chromosomes. 
B. The second of the fundamental questions concerning variations, 
namely, the method of their transmission, may now be approached. In this 
connection four theories, those of Lamarch, Darwin, Weissmann and Mendell 
stand out conspicuouslj'. 
1. Lamarck—The Inheritance of Acquired Characters. This theory in- 
volves the principle that changes in organs brought about by use and disuse 
are transmissable to the offspring. In the human body there are a number of 
vestigial organs which represent structures that were once useful. The de- 
generation of the digestive tract in intestinal parasites like the tapeworm is 
closely associated with the disuse of that organ. The Neo-Lamarckians of 
today claim that the germ plasm responds directly to the changes in the body, 
and these in turn go back to the conditions of the external environment. No 
experimental proof, however, has been offered to substantiate this theory. 
On the contrary there is abundant evidence that changes in the soma have no 
effect upon the germ-plasm. 
2. Dari An—Natural Selection and Pangenesis Theory. The first theory 
is based upon the fact of universal variability. There being more organisms 
born than can possibly survive, a struggle for existence ensues among various 
groups and among the members in each group. The result, as Herbert 
Spencer has so aptly phrased it, is the survival of the fittest. Darwin added 
another factor as a corollary to his first theory, namely, that of Sexual 
Selection. In this way he explained the brilliant colorings of male birds 
and the probability of the strongest males reproducing their kind. In 
order to explain how the new variations got into the egg or sperm he devised 
the Theory of Pangenesis, according to which every cell in the body produces 
minute particles called “gemmules,” which are of the same nature as the 
cells producing them. These gemmules which constitute a miniature replica 
of the parent’s body finally congregate in the reproductive cells. This theory, 
which would allow of the transmission of acquired characters, has been shown 
to have no basis in fact. 
3. Weissmann—Germ Plasm Theory. According to this theory only germ 
plasm can be transmitted. The somatoplasm is concerned only with the in- 
dividual and plays no part in the perpetuation of the race. This theory 
therefore throws out of consideration the transmission of changes in the soma 
of an individual. 
4. Mendel—Segregation of Characters—Laws of Dominants. Entirely 
independent of cytology Mendel worked out a number of laws which have been 
universally accepted. His theories are the result of the experimental breeding 
of plants. The Law of Segregation postulates the existence of unit character 
contributed by the reproductive cells of both parents. These do not blend but 
remain in their original purity and can be segregated. The second law affirms 
that unit characters are either dominant or recessive and will appear in sub- 
74 sequent generations in accordance with the principle of the “Mendelian Ratio. ’ 
It is thus seen that proof for the method by which variations arise is 
far from complete. 
All of the theories so far advanced lack conclusive evidence. This much, 
however, has been accepted. No variation is transmitted unless the germ 
plasm has been affected. Tn other words a rearrangement of the chromatin 
material must occur. Whether environmental conditions play any part is still 
a matter of dispute. It is conceded, however, that certain diseases, like syphilis, 
and possibly certain drugs, may directly modify the germ plasm. Once a 
change has occurred in the germ plasm, however, it will be transmitted in 
accordance with the laws of Mendelian Heredity. 
In the dissecting and operating rooms variations in the human body arc 
often met. These are not always the result of a haphazard development. 
They may be present as normal structures in other animals and their signifi- 
cance in the human can only be appreciated in the light of the evolutionary 
teachings of comparative anatomy. Man is but one rung, even though that 
be the highest, in the ladder of evolution. He belongs to the class of Primates 
and it is important that we glance hurriedly at the chief characteristics of 
the group. They are: (1) Chiefly aboreal animals living on fruits, (2) pre- 
hensile limbs with thumb and great toe shorter than the other digits and 
opposable, (3) plantigrade walking position of the feet, (4) terminal flat- 
tened nails instead of claws, (5) single pair of pectoral mammae, (6) brain 
large and convoluted. 
According to the Classification suggested by Prof. W. K. Gregory, the 
group may be divided as follows: 
Sub-Order 1. Lemuroidea (Lemurs or Half Apes). Most primitive. 
The cerebral hemisphere is so small that it does not cover the hind- 
brain. The second finger retains the ancestral claw. During the 
Eocene period they lived both in North America and Europe, thus 
showing their great antiquity. 
Sub-Order 2. Anthropoidca 
Series 1. Platyrrhini (New World Apes). Have broad nasal septum. 
Thumb is not opposable but usually reduced to a small vestige. 
The tail is long and prehensile. 
Family 1. Hapalidae (Marmosets). Small squirrel-like monkeys 
with a long hairy non-prehensile tail. Have claws instead 
of nails. 
Family 2. Ccbidae (Capuchins, howler monkeys, spider mon- 
keys). Have flat nails instead of claws and usually a pre- 
hensile tail. 
Series 2. Catarrhini (Old World Apes and Man) 
Family 1. Cercopithecidae (Baboons, mandrills, macaques). Quad- 
rupedal habit of locomotion, dog-like heads, no vermiform 
appendix, omnivorous in diet, large canine teeth. 
Family 2. Simiidae (Gibbon, orang, chimpanzee, gorilla). The 
man-like or anthropoid apes. Tail is rudimentary. Arms are 
longer than legs. There is a vermiform appendix. The hair 
is mainly on the ventral surface of the body and the limbs. 
Family 3. Hominidae. 
75 The primates arose probably about the dawn of the Eocene era. They as 
well as the carnivores, sprang from a common insectivore stock. The last- 
named group which included shrews, hedgehogs and moles, were very plastic 
and progressive mammals. In the Miocene era geologic changes caused the 
ancestor of man to come down from the trees—a step essential to further 
human progress. Continental elevation brought with it increased aridity of 
climate, especially to the north of the Himalayas. With this increased aridity 
and lessening of the tropical heat came the dwindling of the forests and the 
ape-man was forced to come to earth. Evidence points to Central Asia as 
the birthplace of mankind and to the Miocene era one to two million years 
ago as the time. Modern man, however, did not develop at once. Fossil 
remains discovered within recent years, have shown that tentative men were 
produced. There are no living representatives of these men today. The 
earliest of the prehistoric human species was Pithecanthropus crectus, who 
lived in the late Pliocene era about half a million years ago. He had a 
gibbon-like skull-top and a brain about two-thirds the size of modern man, a 
modernized human femur and subhuman upper molars. Homo Palcanthropus 
Heidelbergensis, who appeared in the Pleistocene age about 400,000 years ago, 
had a massive jaw that was more simian in character than human. He lacked 
entirely the chin prominence which is characteristic of modern man. The 
Piltdown Man (Eoanthropus dawsoni) also lived in the lower Pleistocene era 
in the second or third interglacial period. The skull which was found in- 
dicated a large brain and high forehead. Homo neanderthalensis had a big 
brain, great ape-like eye-brow ridges and massive jaws. He used fixe and 
fashioned implements. He disappeared about the end of the fourth great 
Ice Age. 
VARIATIONS IN MAN 
Prof. Huntington’s classification of the variations that occur in man will 
be followed in this paper. The variations are divided into two groups, onto- 
genetic and phylogenetic. In the former class there are placed these structures 
which occur normally in the embryo but are not carried into the typical adult 
organization. In the latter class there are grouped those structures which 
are not ordinarily found in the embryo but which either indicate a reversion 
to some ancestral type, in as much as they are found as normal structures in 
the ancestors of the species, or else mark progressive evolutionary change*'-. 
1. Ontogenetic Variants 
A. Errors in Development: 
The majority of the ontogenetic variants naturally fall into this class. 
The fact that man in his development recapitulates his phyletic history means 
that structures will appear in the embryo which are either lost or greatly 
altered in the adult. Many of these early structures persist as vestiges in the 
normal body. The human body is a veritable museum containing many relics 
which at one time played important roles, but which today are of no use and 
merely serve to indicate man’s line of descent. As Darwin himself put it. 
“Man still bears in his bodily frame the indelible'stamp of his lowly origin.’ 
The “plica semilunaris” is a crescentic fold of membranes in the inner upper 
corner of the eye. It is well-developed in birds and in may mammals, as the 
rabbit, where it acts as a nictitating membrane and is used in cleaning the 
front of the eye. In man and monkey it has dwindled due to the fact that the 
upper eyelid has become much more mobile. Some men show on the in- 
76 wardly turned margin of the ear trumpet a little conical projection. This is 
known as “Darwin’s Point,” and is a vestige of the tip of the pointed ear 
of the lower mammals. The pineal body of the brain is connected in rep- 
tiles, notably Hatteria, with a third eye, which really represents a pri- 
mordial vertebrae eye. In man this is present as a vestige hidden beneath 
the mass of the fore-brain. The vermiform appendix, which in the herbivora 
is large and of high digestive value, the direction of the hair on the body, the 
grasping power of the infant, the strong inward deflection of the feet of the 
foetus together with the mobility and distinct projection of the great toe 
at an angle from the side of the foot which persist in the early months of 
extra-uterine life, all indicate man’s relationship to the lower forms. 
1. Arrest of Normal Development. 
This is one of the most frequent causes of variations under the general 
heading of errors in development. An example is the hare-lip. The upper lip 
is produced by the fusion of three parts. If these fail to unite a cleft between 
the nostrils and mouth results. The only adult animals in which such a condi- 
tion persists are the sharks and rays. Cleft-palate is often combined with 
hare-lip. This represents an arrest at a later stage of development. The parts 
of the upper lip are united before the end of the second month of foetal life 
but the right and left outgrowths which meet along the roof of the mouth to 
form the palate are not completely joined until the end of the third month. 
In amphibia, reptiles and birds the three parts representing the upper lip unite 
but a cleft palate remains. This condition may therefore be considered 
reptilian in character. 
2. Failure of Normal Development. 
Sometimes a muscle or group of muscles fail to develop. A child 4 
months old, was admitted to the Presbyterian Hospital (case No. 22,195), 
was found to be suffering from a congenital absence of pectoralis major and 
minor, intercostal and triceps muscles. Since birth the child had kept the arms 
strongly flexed and the hands extended. If the arms were straightened out 
forcibly they assumed the flexed position as soon as the external force was 
removed. 
3. Atypical Development of Vestigal Structures of a Transitory Char- 
acter in Normal Development. 
The aorta may arch over the root of the right instead of the left lung, 
a condition that is normal for birds. In such a case the aorta descends on the 
right side of the vertebral column. A transposition of the other viscera is 
commonly associated with such an arrangement. Less frequently the aorta, 
after arching over the root of the right lung, runs down the left side of the 
vertebral column. This latter peculiarity is not accompanied by a transposi- 
tion of the viscera. This may appear at first glance to be a reversionai 
character referable to the avian type and thus show a relationship between 
bird and man, but there is abundant proof to the effect that mammals did 
not develop from the birds. 
Sometimes the aorta subdivides soon after its origin into two branches 
which soon reunite. This is the normal condition of the vessel in the reptiles. 
4. Atypical Development of Permanent Vestigial Structures. 
Man has thin bands of muscles which are arranged to move the ear, and 
these are normally functionless. Probably when man assumed the erect posi- 
77 tion with eyes looking forward the head became more movable and rendered 
unnecessary the moving of the ear to aid in the appreciation of sound. In 
some individuals the muscles retain their original function, a condition anala- 
gous to that in the lower apes and quadrupeds. 
5. Errors in the Definition of Muscular Integers. 
In order to appreciate the errors that may take place in the definition of 
muscle integers, it may be well to briefly review the normal embryological 
development of these units. The skeletal muscles, with the exception of those 
connected with the branchial arches, are derived from the myotomes of the 
mesodermic somites. The fibres of each myotome are at first loosely arranged 
Later they become more compact and are then arranged parallel with one 
another, their long axis running antero-posteriorly. Then one or more of the 
following changes occur: 
1— Cleavage 
2— Segmentation 
3— Migration 
4— Metamorphosis 
5— Fusion 
The first three may be illustrated by the development of the pectoral 
group of muscles. Lewis describes the Pectoralis Major and Minor and the 
Subclavius as arising from a pre-muscle mass which is located in the lower 
cervical region on the medial side of the arm bud, anterior to the first rib. 
The mass thus lies at first in the region of its nerve supply, receiving branches 
from the sixth, seventh, and eighth cervical and first thoracic nerves which 
proceed almost directly lateral. This mass, as development proceeds, moves 
from its ontogenetic point of origin to the position obtained in the adult. This 
is known as migration. In the 14 mm. embryo, the caudal end of the muscle 
mass has extended to nearly the tip of the fifth rib and the fibres arise from 
the upper five ribs and the anlage of the sternum and clavicle. At the same 
time, through the process of cleavage, the mass has split into a superficial or 
ecto-pectoral group which will become the three parts of the Pectoralis Major, 
and a deep or entopectoral group, which will split into the Pectoralis Minor 
and the Subclavius. In the 16 mm. embryo, the Pectoralis Major extends to 
the sixth rib and shows a differentiation between the costal and clavicular 
portions. This splitting of the ecto-layer into distinct parts (clavicular, costo- 
sternal, and abdominal) is known as segmentation. By this same process the 
ento-layer divides into the Subclavius and the Pectoralis Minor. 
These changes may be graphically represented as follows: 
Pre-Pectoral Muscle Mass 
Cleavage 
I 
Ecto-Pectoral Group 
I 
Ento-Pectoral Group 
Segmentation 
Segmentation 
Clavicular 
Portions of Pectoralis Major 
Sterno-Costal 
i 
Abdominal 
I 
Subclavicus 
Pectoralis Minor 
78 In metamorphosis we have a degeneration of muscle tissue into fibrous 
and ligamentous tissue. This change may affect either the whole myotome 
or a portion of it. Many of the aponeurotic sheets and ligaments of the 
human body are thus formed. The Lumbar Aponeurosis and the Aponeurosis 
of the Oblique and Transverse Abdominal muscles may be given as examples. 
In fusion parts of successive myotomes unite to form a single muscle. The 
Rectus Abdominis is formed by the fusion of the ventral portions of the last 
six or seven thoracic myotomes. 
It is at these various stages in the development of the muscles that the 
errors may arise. It is important to note that while these variants are 
atypical in humans, they may be normal constituents of animals of other 
mammalian orders. We must constantly bear in mind the fact noted earlier 
in this paper, that the human embryo in its development repeats its phyletic 
history. 
a. Errors in Cleavage Into Successive Muscular Planes: 
An example of this would be the Tensor Semi-Vaginae Articulationis 
llumero Scapularis one of the deep supernumerary muscles in the ecto- 
entopectoral interval. When that muscle is present, there is a deficiency 
in the Pectoralis Major between the cartilages of the third and fourth ribs 
near the sternum. It passes laterally, distal to the Subclavius and Coracoid 
Process. It then expands into a strong triangular tendon, which continues 
beneath the ventral margin of the Deltoid and joins the deep layer of the 
Deltoid fascia, thus gaining an indirect attachment to the lateral humeral 
ridge and tuberosity. The fact that it corresponds to the deficiencies in the 
Pectoralis Major and that it is innervated by the Anterior Thoracic Nerves, 
indicates that it is a displaced segment of the Pectoralis Major. Although 
it retains its characteristic ectopectoral origin, it shifts its humeral insertion 
toward the Coracoid Process. It will be recalled that it is only in man and 
anthropoid apes that the Pectoralis Minor is inserted into the Coracoid 
Process. In the lower forms it is attached to the humerus. The insertion 
of the Tensor Semi-Vaginae does not quite reach the Coracoid Process, but 
terminates as a slip intermediate between the insertions of the Pectoralis 
Major and Minor. It thus obtains an indirect humeral attachment through 
the Subdeltoid Aponeurosis. 
The Sterno-chondro-humeralis, which is a normal constituent of the 
pectoral musculature of some of the lower mammals, corresponds in all 
essential features to this human variant and may therefore be considered 
its homologue. 
b. Errors in Segmentation Into Components Within the Coniines of a Single 
muscular plane: 
As an illustration of a muscle formed by such an error, we will take 
the Pectoralis Quartus. This muscle which, when present, is usually associated 
with the Axillary arch, represents as Prof. Huntington writes, "an incom- 
plete stage of that differentiation from the Ventro-appendicular muscle sheet 
which we must regard as the final step in the production of the general 
panniculus.” The Panniculus Carnosus is the skin-moving muscle of the 
lower mammals and is used by these animals as a protection against the bites 
of insects. It is a thin, flat muscle, found directly under the skin, spread- 
ing over the side of the body of the animal and in some cases extending to 
79 the mid-dorsal and mid-ventral lines, incasing the trunk in a subcutaneous 
muscular sheet. It is present in the Monotremes and in many of the other 
forms of mammals, but is normally absent in man. It occasionally manifests 
itself in man in the form of the Pectoralis Quartus and the Axillary Arch. 
The Panniculus is frequently encountered as in Rodents, in two layers—a 
superficial and a deeper layer. The latter is intimately connected with the 
Pectoralis Major. The Pectoralis Quartus belongs to this deeper layer—its 
segmentation from that part of the Panniculus being incomplete. 
In as much as the Pectoralis Quartus is a rudiment of a muscle normally 
found in mammals, it has a phylogenetic significance and may be regarded 
as a progonal variant. The same may be said of the Tensor Semi-Vaginae 
whose homologue is found in lower mammals. 
c. Errors in Migration: 
An example of this type of error is the much-discussed Sternalis muscle 
which is present in about 4% of persons. It is a small muscle which lies in 
front of the thorax parallel with the sternum. It arises from the aponeurosis 
of the External Oblique and the lower true ribs and cartilages and inserts 
into the sternal tendon of the Sterno-Cleido-Mastoid or fascia over the 
Pectoralis Major. It may be present in one of three types: 
1. Well-developed Sternalis with a corresponding deficiency in the sterno- 
costal portion of the Pectoralis Major. 
2. Slender and delicate ribbon-like Sternalis overlying a normal Pec- 
toralis Major having no deficiency. 
3. Sternalis directly connected with the Pectoralis Major, the muscular 
fibres of both being continuous, or the latter taking origin from part of the 
former. 
Several theories have been advanced to explain the presence of this muscle. 
Some believe it to be the downward prolongation of the Sterno-Cleido- 
Mastoid, others that it represents the upward prolongation of the Rectus 
Abdominis. Turner considers it a reversional part of the Panniculus. Cun- 
ningham and Eisler call it a displaced and rotated segment of the Pectoralis 
Major. They emphasize the fact that both muscles are innervated by the 
same nerves (Anterior Thoracic). Of these various theories, the last one 
seems to be confirmed by embryological findings. According to Lewis the 
pro-pectoral mass during its ontogenetic migration laterally and caudally, div- 
ides into a deep and superficial plane. The deep pectoral plane becomes attached 
to skeletal points and is arrested at an early period. The superficial fibres, 
however, continue to descend and soon overlap the deeper layer. While these 
superficial fibres are still free, some etiological force may cause its superior 
portion to become attached to the sternal tendon of the Sternal-Cleido- 
Mastoid, or else it may become included in the closure of the sternal bars 
in the mid-line during the formation of the adult sternum. The superficial 
fibres continue to migrate caudally, swinging the attached portion into a 
vertical position, and we have a Sternalis. If a large part of the Pectoralis 
Major becomes fixed, a Sternalis of type results. If only a small part of 
it is affected there is no deficiency in the muscle and we have the type 2 
variant. Type 3 occurs in cases in which the separation is not complete. 
d. Errors in Metamorphosis: 
The lesser sacro-sciatic (sacro-spinous) ligament is intimately associated 
80 with the ischio-cocvgeus muscle and it is regarded as having been derived 
from it by fibrous transformation of the muscle fasciculi. The transforma- 
tion may not be complete and part of the ligament may be made up of muscle 
fibres. 
B. Reversional Ontogenetic Variants: 
These variants appear normally in the embryo but are usually lost in the 
course of later development. If they persist, they have a reversional signifi- 
cance because they can be referred back to normal structures in lower 
animals. An example of such a variant is that of thirteen free ribs, occa- 
sionally found in man. This condition is normal for anthropoid apes with 
the exception of the orang. An interesting human case was described by 
A. Low in the Journal of Anatomy and Physiology (vol. 34). The subject 
was a male. He had thirteen pairs of ribs of which eight joined the sternum. 
The thirteenth rib on the right side was 41 mm. long and that on the left 
side 69 mm. They articulated with the twentieth, or first lumbar, vertebra. 
In this specimen the first sacral was not fused with the other sacral verte- 
brae, a condition which is frequently associated with thirteen ribs. In 
other words, the forward migration of the pelvis had been arrested at the 
twenty-sixth vertebra. Wiedersheim states that the thirteenth rib, which 
appears in the embryo, begins to degenerate as soon as the twenty-fifth 
vertebra is incorporated in the sacrum. 
At the Orthopaedic Hospital there are some twenty cases on the current 
record of variations in the number of ribs. A few of them are of the rever- 
sional type described above. If the variation is asymmetrical, there is apt to 
be asymmetry in the vetebral body formation. A case is that of F. J., 
female, age 3p2, who had a slight deviation of the spine to the right. It was 
found that there were 13 ribs on the right side and 12 on the left. 
Another reversional variant in the adult human which is normal is the 
embryo, is supernumerary mammary glands. In the six-week embryo there 
appears a thickening in the ectoderm extending along the body wall from 
the axilla to the groin. This is the primary mammary ridge or milk line. 
If more than one pair of mammae persist in the adult, the condition is 
comparable to that in the lower mammals. Two such cases are on record at 
the Roosevelt Hospital (B-16,126—a female, 45, having an additional mam- 
mary gland in the upper and outer quadrant of the left breast extending 
towards the axillary fold; and \A 14,080—a negro male, 51, having an acces- 
sory gland in the skin of the right axilla). 
C. Progressive Ontogenetic Variants: 
A tendency to the disappearance of more ribs in man is seen occasion- 
ally in the loss of the twelfth rib as a free skeletal segment through its 
synostosis with the nineteenth vertebra. There are cases at the Orthopaedic 
Hospital which show an intermediate step in the disappearance of the twelfth 
ribs. The ribs are still present as free skeletal structures but are greatly 
reduced in size. There are other cases in which they have entirely dis- 
appeared as free segments and are present merely as enlarged transverse 
processes of the vertebrae. A case of the intermediate type is that of C. A., 
male, age 24, who had twelfth ribs which formed joints with the nineteenth 
vertebra, but were only V/2 inches long. A case in which complete dis- 
appearance had occurred is that of A. M., male, age 27, who had 11 pairs of 
ribs and 6 lumbar vertebrae. 
81 2. Phylpgenetic Variants 
A. Reversional Phylogenetic Variants: 
In this class of variants will be found structures that do not appear 
normally in the embro, but occur typically in lower animals. They are 
divided into 3 groups: (1) archaeal—those that can he referred back to the 
promammalian forms; (2) progonal,—those that go back only as far as the 
mammalian stem, and (3) ataval,—those that are present in the primate or- 
ganization. 
1. Archaeal Group consists of variants which go back the furtherest in 
man’s phyletic history. These appear as typical structures in the ancestors of 
the mammals. An example is the ent-epicondylar foramen (Plate I), an 
opening on the inner side of the lower end of the humerus. It is found 
nearly always in fossil reptiles. The functional significance of the foramen 
is probably the protection of the brachial artery and median nerve, which 
pass through it, against severe pressure in the forcible flexion at the elbow 
joint. It was therefore widely distributed among the active and powerful 
early reptiles, but it has been lost in their creeping descendants, with the 
exception of “Hatteria punctata.” To-day it is found variously distributed 
among mammals, especially in those forms that use their anterior extremity 
extensively. The foramen is not present in birds. 
Progonal Group: In this class are placed the variants which occur 
Figure 2. Schemata showing the effect of the introduction of the clavicle on the 
disposition of the M. Stemo-costo-scapularis. 
A. Primitive condition. M. Sterno-costo-scapularis, as it occurs in non-claviculate 
mammals and in the human variant, without attachment to the clavicle. 
B. The central portion of the muscle acquires a secondary attachment to the 
clavicle, resulting in the establishment of two derived muscles, the Costo-clavicularis and 
Coraco-clavicularis. 
C. Typical condition in Man. Some of the proximal fibres of the Costo-clavicularis 
metamorphose into the Rhomboid ligament, the main portion of the muscle becomes the 
Subclavius and the Coraco-clavicularis furnishes the Conoid and Trapezoid ligaments. 
D. Human variant. The normal Subclavius and Clavicular ligaments are associated 
with a Costo-scapularis. 
82 as normal constituents in animals falling within the limits of the general mam- 
malian organization. The Sterno-costo-scapularis muscle (Fig. 2 and Plate V) 
may be taken as an example of such a variant. This muscle is widely distrib- 
uted in land-living non-claviculate mammals, such as the ungulates. It extends, 
in its primitive form, from the manubrium of the sternum and the first costal 
cartilage to the Coracoid Process and the adjacent cranial border of the 
scapula. In the lower claviculate mammals, as the Rodents, the muscle gets 
an intermediate attachment to the clavicle, resulting in the formation of two 
muscles: Costo-clavicularis and Coraco-clavicularis. In the higher forms, 
such as Man and the Prima.es, the proximal fibres of the Costo-clavicularis 
muscle have changed, through the process of metamorphosis into the Costo- 
clavicular (Rhomboid) Ligament, while the main portion of the muscle has 
become the Subclavius. The Coraco-clavicularis muscle has metamorphosed 
into the Coraco-clavicular Ligaments (Conoid and Trapezoid). As a variant 
in man, the Sterno-Costa-clavicularis muscle may appear alone, just as it 
does in non-claviculate mammals, or it may exist together with a normal Sub- 
clavius. In the latter case, it is referred to as “reduplication of Subclavius.” 
At aval Group: These variants go back to a more recent ancestry than 
either of the other two groups. A good example is the default of the 
Peroncus Tertius, a condition which occurs quite frequently. In Man, the 
Tibialis Anterior and Posterior tend to invert the foot. This is the condition 
found normally in apes. These animals are thus compelled to walk upon the 
lateral border of their feet. This action is antagonized by the Peroneus 
Longus and Brevis. The latter two muscles, however, are not sufficient to 
overcome the inverting power of the Tibialis muscles. Hence, a new element 
appears in man to aid in neutralizing this inverting tendency. This additional 
muscle is the Peroneus Tertius which is formed from the distal portion of 
the Extensor Digitorum Longus. The three Peronei muscles, now acting 
together counteract the effect of the invertors and Man is thus able to walk 
upon the plantar surface of his feet. His fully erect position is thus made 
possible. The Peroneus Tertitus is a distinctly human muscle and is absent 
even in the Anthropoid Apes. Its absence in Man is therefore a reversion 
to the Primate Type. Recently an incompletely developed Peroneus Tertius 
was found by Prof. Huntington in a male gorilla. This constitutes a pro- 
gressive variation for the ape. 
Normally in the lower primates, instead of a Peroneus Tertius there is 
an Extensor Quinti Digiti Brevis which arises from the fibula in close rela- 
tion to the Extensor Digitorum Longus. Its tendon descends in company 
with the Peroneus Brevis and is inserted on the lateral side of the long 
Extensor tendon to the fifth toe. There is occasionally found in a human 
subject a Peroneus Brevis which, before reaching its normal insertion into 
the base of the fifth metatarsal, gives off an additional tendon which passes 
to the Long Extensor tendon. This would likewise be a reversional character, 
but it would be progonal in nature because it may be traced back to the 
common mammalian stem. It illustrates a condition which is normal in the 
Monotremes. 
The Peroneus Tertius itself may sometimes send an additional tendon to 
the fifth, or even the fourth toe, thus betraying its primitive derivation from 
the Extensor Digitorum Longus. 
The humeral insertion of the Pectoralis Minor is another illustration of 
an ataval variation. 
83 b. Progressive Phylogenetic Variants 
These illustrate the evolutionary processes which are at present active in 
man. Characters appear which perhaps some day will be part of the normal 
human structure. 
1. Advance in the Vertebral Level of the Pelvic Girdle. 
In the evolution of man and the higher apes there has been a shortening 
of the longitudinal body ajcis due to the forward shift of the pelvic 
arch. The normal adult presacral portion of the vertebral column con- 
tains 7 cervical, 12 thoracic and 5 lumbar vertebrae. Thus the 25th verte- 
bra is normally the first sacral element. The synostosis of the sacral segments 
has gone in a caudio-craniad direction. Man bears evidence of this in the 
fact that the second sacral vertebra is less completely fused with the first 
than it is with the third. In man the advance of the pelvic arch normally 
terminates when the 25th vertebra becomes incorporated in the sacrum. In 
some cases the number of presacral vertebrae is reduced to 23 (Plate II). 
This is a further advance in pelvic migration and is of progressive significance 
because it anticipates a change that has not yet occurred in the great ma- 
jority of the species. This advance may be on one or both sides. The 
opposite condition sometimes occurs. The presacral vertebrae is increased 
to 25 (Plate III). In this case the pelvic advance is retarded and the variant 
is of a regressive type. 
It is interesting to note that in the three higher anthropoid apes, Orang, 
Chimpanzee and Gorilla the pelvic migration has been carried one segment 
further than in Man. This may be interpreted as an attempt to counteract 
the inadequacy of visceral support by the pelvis, especially the lateral ex- 
pansion of the ilium. In the Gibbon, on the other hand, the pelvic shift has 
been arrested one segment further caudad than in Man. Thus, as far as 
pelvic advance is concerned, Man occupies an intermediate position between 
the higher Anthropoids and the Gibbon. 
Cases of sacralized 5th Lumbar vertebrae in Man are not uncommon. 
The following cases were obtained at the Orthopaedic Hospital. No. 56,542 
—Male, 32—Back and right hip painful. Marked limitation of motion in the 
lower lumbar region. Some limitation of lateral bending to the left, more 
to the right. X-ray showed sharp lumbo-sacral angle. Transverse processes 
of 5th Lumbar in abnormally close relation to the wings of the sacrum. 
No. 52,940—Female, 37—Pains in lower region of back for 8 or 10 years. 
X-ray showed that the lower lumbar transverse process on the right side was 
bifid, the lower horn articulating with the wing of the sacrum and the ilium. 
The left transverse process impigned against the wing of the sacrum. The 
spinous processes of the 4th and 5th lumbar appeared in abnormally close 
relation. 
Operation—spinal fusion of 5':h lumbar to sacrum. 
2. Congenital Absence of the Vermiform Appendix in Man. 
Instances of such a variant are rare. In the cases reported, the caecal 
outgrowth from the embryonic intestine develops only sufficiently for the 
establishment of the normal adult pouch (Plate IV). The distal portion, which 
would ordinarily give rise to the appendix, defaults. In as much as the 
appendix is merely a vestige in Man its disappearance may be regarded as 
of progressive significance. 
84 3. Progressive Peroneus Tertius. 
An interesting anomaly of the Peroneus Tertius (Fig. 3) was found 
in a Chinese male, age 54, in the Anotomical Laboratory of the Peking Union 
Medical College. In both legs the muscle had a fleshy origin from nearly 
Figure 3. Semidiagrammatic drawing showing relations of anomalous peroneus 
tertius and extensor digitorum longus. Other anterior leg muscles represented by their 
cut tendons only. (After Stevenson.) 
the entire length of the anterior part of the medial surface of the fibula. 
A very small Extensor Digitorum Longus had an origin in the proximal 
5 cm. of the bone. There was a space of 3 cm. between the lower margin 
of the Extensor Digitorum Longus and the upper margin of the Peroneus 
Tertius. The margins of the muscles were well rounded and distinctly 
formed. The anomalous muscle gave rise to a strong tendon which passed 
beneath the transverse and cruciate ligaments and divided into two separate 
tendons which became inserted into the base of the fifth metatarsal and the 
first phalanx of the little toe. The small Extensor Digitorum Longus gave 
rise to a very slender tendon which began at the upper margin of the 
Peroneus Tertius and passed down the leg, under the transverse and cruciate 
ligaments, subdividing on the dorsum of the foot into three smaller tendons 
having their insertions on the proximal phalanges of the second, third and 
fourth toes. Branches from the deep peroneal nerve supplied both muscles. 
The Peroneus Tertius is a distinctly human muscle being normally absent 
85 in all lower forms. It is usually considered as a differentiated portion of the 
Extensor Digitorum Longus and its variants are commonly interpreted as 
mere variations in the degree of differentiation from this muscle. But this 
anomalous Personeus Tertius seemed to be much more than this. It had 
almost completely usurped the position of the Extensor Digitorum Longus 
without assuming a proportionate share of its function 
The right calcaneus of this cadaver showed a striking deformity. The 
part of the bone bearing the main articular facet and receiving the greater 
part of the weight of the body through the talus was tipoed laterally on its 
antero-posterior axis, indicating that the forces responsible for this impaction 
came while the foot was in a position of strong eversion. 
It will be recalled that apes normally have no Peroneus Tertius and 
that they walk with their feet inverted. It is through this muscle that the 
human foot has attained its plantigrade position. In the variant just described 
the muscle has developed much further than in the normal individual and 
has strongly everted the foot. It is evident that in this case Nature has 
gone one step further, and thus this variant indicates what we may expect 
in the way of further evolutionary change in the human foot. 
In conclusion we may state that evolution has occurred through the 
transmission of variations from parent to offspring. Just how these varia- 
tions arose is by no means clear. Somehow or other the germ plasm was 
affected and a rearrangement of chromatin material took place. Once a con- 
gential variant arose it reproduced itself in accordance with the laws of 
Medelian heredity. If this variant were of a progressive nature and made 
its possessor better equipped than his fellows to adapt himself to the envir- 
onment, it was very apt to survive and become incorporated into the general 
make-up of the species. The variations that occur in Man and that are not 
fortuitus may have an ontogenetic or phylogenetic interpretation. If of the 
former type they represent some stage of development which is normally 
present in the embryo. If of the latter type, they are not normally present 
in the embryo but are either found as typical structures in Man’s ancestors 
or else are of a progressive type and indicate the probable path of future 
evolutionary change. 
Whether Man is to climb still higher it is difficult to say. Some believe 
that the Law of Adaptive ‘Radiation has ceased as far as Man is concerned 
and that any change now is largely retrogressive. They point to such changes 
as the reduction of hair and of teeth and the dulling of the senses of sight, 
hearing and smell. But evolution does not imply the constant improvement 
in function of a given organ. The reverse has often occurred in the evolu- 
tionary history of many species. However, if the evidence be carefully 
weighed and interpreted in the light of the phyletic history of the race, it 
seems very probable that variations of the type considered last point the 
direction to which Man is headed. 
Conclusion 
BIBLIOGRAPHY 
Huntington, George S.: “Modern Problems of Evolution Variation and Inheritance.” 
Anatomical Record, vol. 14, June 1918. 
Huntington, George S.: “The Derivation and Significance of Certain Supernumerary- 
Muscles of the Pectoral Region.” Journal of Anat. and Physiol., vol. 39, Oct. 1904. 
86 Huntington, George S.: “Present Problems of Myological Research and the Signi- 
ficance and Classification of Muscular Variations.” Amer. Journal of Anatomy, vol. 2, 
March 1903. 
Huntington, George S.: “The Significance of Muscular Variations, Illustrated by 
Reversions of the Anti-Brachial Flexor Group.” Trans. N. Y. Acad. Sci., vol. 14, 
Aug. 1895. 
Stevenson, Paul H.: On an Unusual Anomaly of the Peroneus Tertius in a Chinese. 
Anat. Rec., vol. 22, Aug. 1921. 
Baitsell, G. A. (Editor): Lectures on the Evolution of Man. Yale University Press, 
1922. 
Newman, Horatio H. (Editor): Readings in Evolution, Genetics and Eugenics, 
Univ. of Chicago, 1921. 
Lull, Richard S.: Organic Evolution. Macmillan Co., 1917. 
Lock, Robert H.: Recent Progress in the Study of Variation, Heredity and Evolution, 
London, 1916. 
Morgan, Thomas H.: Critique of the Theory of Revolution. Princeton University 
Press, 1916. 
Osgorn, Henry S.: The Origin and Evolution of Life. 
Thompson, J. Arthur: Heredity. London, 1908. 
Leche, W.: Der Mensch—Sein Ursprung und Seine Entwicklung. (Gustave Fischer, 
Jena, 1911.) 
Jennings, H. S.: The Problem of the Method of Evolution. Scientific American 
Sup., vol. 85, 1918. 
Wiedersheim, R.: The Structure of Man—An Index to His Past History. 
Keith, Arthur: Human Embryology and Morphology. 
87 .PLATE i 
EXPLANATION OF FIGURES 
1. Right and left humeri in a specimen of Hyaena striata, showing the 
occurrence of the entepicondylar foramen as a reduced variant on the right 
side. 
2. Left humerus of Felis leo, showing entepicondylar foramen character- 
istic of the Felidae. 
3. Series of adult human humeri with supracondylar process. 
88 PLATE I. 
89 PLATE II 
Adult human instances of phyletic advance of pelvic migration. 
90 PLATE il. 
91 PLATE 111. 
Adult human instances of phyletic retardation of pelvic migration. 
92 PLATE JII. 
93 DORSAL VAS- 
CULAR FOLD 
AND EPI- 
PLOIC FAT 
PLATE IV 
Congenital absence of the Vermiform Appendix in Man. 
94 HUMERAL INSERTION 
OF PECTORALIS MINOR 
POSTERIOR BELLY 
OF OMO-HYOID. 
CORACOID INSERTION 
OF PECTORALIS MINOR 
M. STE R NO-CO STO- 
SCAPULARIS. 
PLATE V. 
Adult Human, M. Sterno-costo-scaplularis. 
95