WORLD SCIENCE SERIES 
Jbo r atory 
MANUAL 
HUMAN 
PHYSIOLOGY 
HARTMAN 
WORLD BOOK COMPANY NEW-WORLD SCIENCE SERIES 
LABORATORY MANUAL 
for 
HUMAN PHYSIOLOGY 
EXPERIMENTAL STUDIES IN HYGIENE 
SANITATION AND PHYSIOLOGY 
/Y 
CARL HARTMAN 
INSTRUCTOR IN ZOOLOGY, &NIVERSITY OF TEXAS; FORMERLY 
PROFESSOR OF BIOLOGY AND PHYSIOLOGY IN THE SAM 
HOUSTON NORMAL INSTITUTE, HUNTSVILLE, TEXAS 
ILLUSTRATED 
YONKERS-ON-HUDSON, NEW YORK 
WORLD BOOK COMPANY 
1914 Copyright, IQ14, by World Book Company. All rights reserved 
HLMHP-I PREFACE 
I he work prescribed in this manual, which has been 
specially prepared for use with Ritchie's Human 
Physiology, is as simple as it is possible to make it and 
the directions are so detailed that any teacher can 
carry out most of the experiments. The size of the 
volume is due to the detailed description of the exper- 
iments rather than to their number. 
In favorable conditions, most of this work can be 
gone through in a half-year. The teacher must 
judge of this for himself and, if pressed for time, 
make a selection from the experiments given. If the 
course is taken as the first of the sciences studied in 
the first year of the high school, less can, of course, 
be done than in the higher grades in the same length 
of time. ; 
The apparatus and Yhaterials Yeiqili'red for the greater 
number of these experiments are comparatively in- 
expensive and in many cases suggestions are given for- 
cheaper substitutes. These, with a little ingenuity 
and care, may be made or procured by the teachers or 
pupils themselves, a specially helpful feature fpr 
smaller schools and schools in rural districts. 
Special attention is called to the chapter How to Use 
this Manual at the beginning and to the list of appa- 
ratus, material, formulae, etc., at the end of the book. 
Thanks are due to Professor John W. Ritchie for 
his helpful suggestions and practical advice in the 
preparation of tlfe work. CONTENTS 
PAGE 
PREFACE ......... iii 
HOW TO USE THIS MANUAL ...... I 
SECTION 
I. ORGANIZATION OF LIVING THINGS (CLASS WORK) . 6 
Exercise I. Matter inorganic and organic . . 6 
Exercise 2. The cell as the unit of structure of liv- 
ing things (Demonstration) ... 7 
Experiments a. How to cut a section and mount it 
for microscopic study . . 7 
b. Pith cells of elder .... 9 
c. An animal cell . . . .10 
d. Cells from the mouth . . .10 
e. Paramecium : a one-celled animal . 11 
Exercise 3. Reproduction of cells (Demonstration) 12 
Experiments a. Paramecium . . . . .12 
b. Yeast . . . . . .12 
c. Cartilage cells . . . .13 
d. Sea-urchin eggs . . . .13 
Exercise 4. Arrangement of cells into tissues 
(Demonstration) . . . . . .14 
Experiments a. Cartilage tissue . . . .14 
b. Connective tissue . . . .14 
c. Epithelial tissue . . . .16 
d. Muscle tissue . . . .16 
e. Nerve tissue . . . . .17 
Exercise 5. Arrangement of tissues into organs 
(Class work) . . . . . . .17 
Experiments a. A muscle . . . . .17 
b. Other organs (Home work) . . 17 
V VI 
CONTEHTS 
SECTION PAGE 
Exercise 6. Plan of the body : arrangement of or- 
gans (Class work) . . . . . .18 
Experiments a. A simple plan: Hydra ... 18 
b. The double-tube plan : the earthworm 18 
c. Exo- and Endo-skeleton . . .18 
Exercise 7. The classification of vertebrates (Home 
work) ........ 20 
Experiments a. The classes of vertebrates . . 20 
b. Comparison of man with other mam- 
mals ..... 20 
Exercise 8. General view of the nervous system 
(Demonstration) . . . . . .21 
Experiments a. The central nervous system . . 21 
b. The sympathetic nervous system . 21 
c. Reflex action . . . .22 
d. Function of a nerve ... 22 
II. THE ORGANS OF LOCOMOTION ..... 23 
Exercise 9. The skeleton (Class work) ... 23 
Experiments a. The human skeleton ... 23 
b. Skeleton of a cat .... 23 
Exercise 10. Observations on the skeleton (Class 
work) ........ 24 
Experiments a. Classification of the bones . . 24 
b. Comparison of human limbs with 
limbs of other vertebrates . 24 
c. Comparison of upper and lower limbs 
of man (Home work) . . 25 
d. The articulation of the vertebrae with 
one another .... 25 
e. The rotation of the hand . . 25 VII 
SECTION PAGE 
Exercise II. The structure of the bones (Class 
work) . ....... 26 
Experiments a. A long bone . . • • 26 
b. A flat or irregular bone . . 26 
Exercise 12. Structure of bone tissue (Class work) 26 
Exercise 13. Materials in bones (Class work) . 27 
Exercise 14. Use of other skeletal tissue (Class 
work) ........ 27 
Experiments a. Connective tissues . . . 27 
b. Cartilage . . . • .27 
Exercise 15. Kinds of joints (Class work) . . 28 
a. Sutures of the skull ... 28 
b. Gliding joint..... 28 
c. Hinge joint ..... 28 
d. Ball-and-socket joint ... 28 
e. Pivot joint ..... 28 
Exercise 16. Structure of a ball and socket joint 
(Class work) ....... 29 
Exercise 17. Protection of the brain (Home work) 29 
Exercise 18. Fractures and sprains (Class work) . 29 
Exercise 19. Levers of the body (Home work) . 30 
Exercise 20. A study of tendons (Class work) . 31 
Experiments a. The long tendons (" leaders " of the 
foot and hand) . . 31 
b. Illustrating the action of a tendon . 32 
Exercise 21. Structure of a muscle (Class work) . 32 
CONTENTS VIII 
CONTENTS 
SECTION PAGE 
Exercise 22. The work of muscles (Demonstration) 32 
Experiments a. How to make a muscle nerve prepa- 
ration . .... 32 
b. How to stimulate the nerve . . 35 
c. Tetanus ..... 36 
d. Fatigue ..... 36 
Exercise 23. Rhythmic contraction (Demonstra- 
tion) 36 
Exercise 24. Model of arm (Demonstration) . 37 
III. FOODS AND DIGESTION (TO ILLUSTRATE RITCHIE, 
CHAPTER VIII) ...... 39 
Exercise 25. Matter and energy. Physical changes 
(Class work) ....... 39 
Experiments a. Water as solid, liquid, and gas . 39 
b. Substances in solution ... 39 
Exercise 26. Chemical changes (Demonstration) . 40 
Experiments a. Synthesis of water ... 40 
b. Analysis of water .... 42 
c. Synthesis of sulfid of iron . . 43 
d. Analysis of oxid of mercury . . 44 
e. Synthesis of oxygen with other ele- 
ments (Combustion) . . 44 
Exercise 27. Testing composition of foods. Pro- 
portion of water in foods (Class work) . . 46 
Exercise 28. Composition of water (Class work) . 46 
Exercise 29. Iodine test for starch (Class work) . 47 
Experiments a. Preparation of starch foods . . 47 
b. Effect of iodine on starch . . 47 
Exercise 30. Test for grape-sugar, dextrose, or 
glucose (Class work) ..... 47 CONTENTS 
IX 
SECTION PAGE 
Exercise 31. Tests for proteins (Class work) . 48 
Experiments a. Preparation of albumen solution . 48 
b. Orange color test for protein . . 48 
c. Violet color test .... 49 
d. Problem ..... 49 
Exercise 32. Tests of various foods (Class work) 49 
Experiments a. Wheat flour..... 49 
b. Milk ...... 50 
c. Testing various other foods for 
classes of foods . . .51 
Exercise 33. Processes of digestion. The need of 
digestion (Class work) . . . . 51 
Experiments a. Soluble and insoluble defined . 51 
b. Diffusion . . . . .51 
c. Diffusion through a membrane 
(Demonstration) . . .52 
d. Osmosis . . . . -53 
(1) Osmosis through the mem- 
brane of an egg 53 
(2) Further proof of diffusion of 
water in an egg . . .54 
(3) Osmosis through the skin of 
prunes..... 54 
(4) Osmosis through a carrot . 55 
(5) Osmosis through a parchment 
tube or a "diffusion shell" . 55 
Exercise 34. More ready solubility of fine particles 
(Class work) ....... 56 
Exercise 35. Chemical digestion (Class work) . 56 
Experiments a. Cane-sugar changed chemically . 56 
b. Starch changed chemically . . 57 X 
CONTENTS 
SECTION PAGE 
Exercise 36. Digestion of starch by saliva (Class 
work) . . . . . . . -57 
Exercise 37. Digestion of protein by gastric juice 
(Class work) ....... 58 
IV. ANATOMY OF THE DIGESTIVE ORGANS 60 
Exercise 38. General view of the viscera (Demon- 
stration )........ 60 
Experiments a. Preparation of the animal . . 60 
b. Dissection of the cat ... 60 
Exercise 39. Internal structure of the organs 
(Demonstration) ...... 63 
Exercise 40. The mouth, the throat, and the sali- 
vary glands (Demonstration) .... 64 
Experiments a. The salivary glands ... 64 
b. Organs of the mouth and throat . 64 
c. The human mouth (Home work) . 65 
Exercise 41. The tongue and the teeth (Class 
work) 65 
Experiments a. The tongue ..... 65 
b. The human teeth (Home work) . 65 
c. The teeth of other animals . . 66 
Exercise 42. Finer structure of the digestive or- 
gans (Class work) ...... 67 
Experiments a. The structure of a tooth . . 67 
b. Cross-section of the esophagus 
(Demonstration) ... 67 
c. Cross-section of the stomach (Dem- 
onstration) .... 67 
d. Cross-section of the small intestine . 68 
e. Glands (Home work) ... 68 CONTENTS 
XI 
■SECTION PAGE 
V. DIETETICS (TO ACCOMPANY RITCHIE, CHAPTER x) . 70 
Exercise 43. Advantages of chewing (Class work) 70 
Exercise 44. Starch grains (Demonstration) . 70 
Exercise 45. Intestinal parasites (Demonstration) 70 
Exercise 46. Cleanliness of foods (Class work) . 71 
Exercise 47. Adulteration of foods (Class work) . 72 
Exercise 48. Patent medicines (Class work) . . 72 
VI. THE CIRCULATION ....... 74 
Exercise 49. The blood (Demonstration) . . 74 
Experiments a. Fresh human blood ... 74 
b. Stained blood .... 74 
Exercise 50. The circulation of blood in a frog or 
a tadpole (Demonstration) .... 75 
Experiment. Tadpole . . . . . -75 
Exercise 51. Color of blood (Class work) . . 77 
Exercise 52. Clotting of blood (Class work) . . 77 
Exercise 53. Structure of the heart (Class work) . 78 
Exercise 54. Tracing the courseof theblood(Home 
work) ........ 80 
Exercise 55. The beating of the heart (Demon- 
stration) ........ 80 
Exercise 56. The lymph vessels of the intestine 
(Demonstration) . . . . . .81 
Exercise 57. Demonstrating the valves in the veins 
(Home work) ....... 81 
Exercise 58. Human pulse and heartbeat (Home 
work) . . . . . . . .81 XII 
CONTENTS 
SECTION PAGE 
Exercise 59. Why the blood flows in a steady 
stream in the capillaries (Demonstration) . 82 
Experiments a. Elastic arteries are required for a 
. steady stream . 82 
b. The resistance offered by the cap- 
illaries is essential for a 
steady stream ... 84 
c. More energy is required to pump 
water into a tube with rigid 
walls than into an elastic tube 84 
d. An elastic tube with elastic walls 
delivers more water than a 
similar tube with rigid walls 85 
VII. RESPIRATION . . . . . 86 
Exercise 60. The lungs and the air passages 
(Demonstration) ...... 86 
Experiments a. The lungs .... 86 
b. The trachea, bronchi, and bron- 
chial tubes ... 87 
Exercise 61. Lung capacity (Class work) . . 87 
Exercise 62. The sweeping action of the cilia 
(Demonstration) ...... 89 
Exercise 63. Chest expansion (Home work) . 90 
Experiments a. Measuring chest expansion . 90 
b. Exercise to increase chest expan- 
sion ..... 90 
Exercise 64. How we breathe (Demonstration). 91 
Experiments a. Raising and lowering ribs (chest 
expansion). . . .91 
b. Lowering the diaphragm (abdom- 
inal breathing) ... 92 XIII 
CONTENTS 
SECTION PAGE 
Exercise 65. Artificial respiration (Class work). 93 
Exercise 66. Number of breathing movements 
(Home work) ...... 94 
Exercise 67. Analysis of air (Class work) . . 94 
Experiments a. Air needed to support combustion 94 
b. Carbon dioxid will not support 
combustion ... 94 
c. Air always contains a trace of CO2 95 
d. Oxygen makes up about one fifth 
of air, nitrogen four fifths . 96 
Exercise 68. Changes in expired air (Class work) 96 
Exercise 69. Respiration in other animals (Class 
work) ...••••• 97 
VIII. VENTILATION 9$ 
Exercise 70. Heated air rises (Class work) . 98 
Exercise 71. Systems of heating and ventilation 
(Home work) 9° 
Exercise 72. Sanitation laws pertaining to venti- 
lation (Home work) 99 
Exercise 73. Open air living (Class work). . 99 
IX. THE KIDNEYS 100 
Exercise 74. The structure of the kidney (Class 
work 100 
Exercise 75. Microscopic study of the kidney 
(Demonstration) . . . • • .100 
X. THE SKIN AND THE BODY TEMPERATURE . . 102 
Exercise 76. A study of Ritchie, figs. 93~96 
(Home work) ...... 102 
Exercise 77. Section of the scalp (Demonstra- 
tion) 102 XIV 
CONTENTS 
SECTION PACE. 
Exercise 78. The growth of the finger nail 
(Home work) ...... 103 
Exercise 79. Heat regulation of the body (Class 
work) ........ 103 
Experiments a. Source and distribution of heat . 103 
ft. Loss of heat from the body . 103 
XI. THE NERVOUS SYSTEM Iq6 
Exercise 80. Dissection of the nervous system 
(Demonstration) ...... 106 
Exercise 81. Reflex action of the frog (Demon- 
stration) . . . . . . .108 
Exercise 82. Reflex action in pupil's body (Home 
work) 108 
Exercise 83. Reaction time (Class work) . . 109 
XII. THE SPECIAL SENSES . . . . . .IIO 
Exercise 84. Touch (Home work) . . .110 
Experiments a. The temperature sense . . no 
b. Delicacy of touch . . .110 
Exercise 85. Distinguishing between taste and 
smell (Class work) . . . . .110 
Exercise 86. Dissection of the ear (Demonstra- 
tion) 
Exercise 87. Tests for hearing (Class work) . 111 
Exercise 88. Dissection of the eye (Class work) 112 
Experiments a. External features of the human 
eye (Home work) . . . . .112 
b. Eye of ox or cat . . .112 
Exercise 89. Accommodation (Home work) . 113 
Experiments a. Accommodation necessary . .113 
b. Muscular effort needed for close 
vision . . . .114 CONTENTS 
XV 
SECTION PAGE 
Experiment c. Observing the eye in accommo- 
dation . . . .114 
Exercise 90. Optical defects (Class work). . 114 
Experiments a. Tests of vision . . . .114 
b. Astigmatism . . . .115 
Exercise 91. Optical illusions (Home work) . 115 
Experiments a. Deception due to habit . . 115 
b. Other illusions . . . .115 
Exercise 92. The blind spot (Home work) . 116 
XIII. THE BACTERIA 117 
Exercise 93. Fermentation and decay (Class 
work) . . . . . . . .117 
Experiments a. Yeast . . . . .117 
• b. Bacteria in milk and vinegar . 117 
Experiments c. Decay . . . . .118 
d. To show that fermentation is due 
to living things . . .118 
e. Hay infusion . . . .119 
f. Infusion of algae . . .119 
Exercise 94. Staining bacteria (Demonstration) 120 
Experiments a. General . . . . .120 
b. The three classes of bacteria . 121 
Exercise 95. Preparation of special culture 
media (Demonstration) . . . .122 
Experiments a. How to sterilize the dishes. . 123 
b. Sterilizing the culture media . 124 
c. Preparation of potato medium . 125 
d. Preparation of nutrient agar me- 
dium . . . . .125 
Exercise 96. Pouring and inoculation of dishes 
or bottles (Class work) . . . .127 XVI 
CONTENTS 
SECTION PAGE 
Exercise 97. Inoculation of potato culture (Class 
work) . . . . . . . .131 
Exercise 98. Studying the cultures (Class work) 132 
Exercise 99. Questions for study (Home work) 132 
APPARATUS, MATERIAL, FORMULAE, ETC. . . .135 
Firms furnishing laboratory supplies . . . 135 
Apparatus indispensable for carrying out the experi- 
ments given in this manual. .... 135 
Desirable apparatus and suggested cheaper substitutes. 
(The substitutes, at least, are indispensable) . . 137 
MATERIAL ......... I4I 
FORMULAE FOR STAINS, SOLUTIONS, ETC. . . . I42 
THE METRIC SYSTEM AND SOME ENGLISH EQUIVALENTS I43 HOW TO USE THIS MANUAL 
The difficulties of overcrowded classes, insufficient labora- 
tory equipment, and limited time given to the subject have 
here been fully considered. The arrangement and presenta- 
tion of matter have been made with the view of helping the 
teacher to furnish the student as much first-hand knowledge 
of Physiology and Hygiene as possible in the existing condi- 
tions in the great majority of high schools. 
The laboratory method. Mere book knowledge of a science 
can rarely become a vital possession, just as the impressions 
received from reading a description of a circus cannot be as 
lasting nor as realistic as those received from a single visit. 
Therefore, as many exercises as possible should be done by 
the pupil himself. 
Three kinds of laboratory exercises. The exercises out- 
lined in this manual are of three kinds,- Demonstration: 
those demonstrated by the teacher or by some one appointed 
by him; Class work: experiments by the pupils under the 
teacher's direction; and Home work: experiments performed 
without the teacher's direction. This apportionment of the 
experiments is, however, merely suggestive, and may be varied 
to suit local needs and conditions. 
Demonstration and class work. Certain of these exercises 
are such that it will be found impossible in most high schools 
for the pupil to do them himself. Some are too difficult, de- 
manding more training than the pupil has ordinarily had ; 
others involve the use of so much apparatus that individual 
work is out of the question. Such exercises as the genera- 
tion of oxygen or hydrogen, the use of the microscope, and 
the dissection of a mammal would best be demonstrated. 
For some of the experiments the equipment and personnel 
of the Chemistry Department could be drafted into service. 
Such cooperation and correlation would be of mutual benefit. 
1 2 
LABORATORY MANUAL 
Writing up the experiments. After each demonstration 
the pupil should be given opportunity to describe the experi- 
ment in writing as carefully as though it had been performed 
by himself. The pupil may be encouraged to spend his 
vacant period in the laboratory making sketches of apparatus 
or specimens. 
Home work. There are many exercises which the pupil 
can perform by himself or with a companion : the study of 
the mouth or of the eyes, the pulse, the heartbeat, reflexes, 
etc. These exercises may profitably be done at home. 
The place of physiology on the program. Some experiments 
cannot be completed in a single recitation period, and if it 
can possibly be arranged, one of the periods of the week in 
this subject should be a double period, i.e. one running 
through two periods of the regular daily program. The 
teacher of the subject should have a vacant period immediately 
preceding the physiology period for preparing the laboratory 
work. 
The use of the microscope. The study of the cell, the 'finer 
structure of the organs, the circulation of the blood, bacteria, 
and the like, requires a compound microscope. Each school 
should have at least one instrument. If the class is large, 
two or more instruments are highly desirable. 
The ideal arrangement would be a course in Physiology 
taken after or parallel with a course in Biology, in which the 
pupil acquires microscopic technic. But this ideal rarely, if 
ever, exists in a high school. For this reason, and in view of 
the general lack of instruments, it is not deemed wise to put 
the preparation for microscopic work into the hands of the 
pupil. All microscopic study of objects is, therefore, to be 
prepared for by the teacher. It is suggested that the teacher 
prepare as many slides as are needed for a given period, and HOW TO USE THIS MANUAL 
3 
show as many of these as possible, at the same time using as 
many microscopes as are available. If the teacher has six 
microscopes and a class of thirty pupils, six specimens should 
be mounted, and a label descriptive of the specimen placed be- 
side each instrument. The pupils should pass around from 
one instrument to the other, making observations. While one 
set of pupils was thus engaged, the others would be busy 
making sketches and discussing the objects with the teacher. 
Dissections. Dissection work can be more easily per- 
formed by the pupils than microscopic work. Any enterpris- 
ing boy or girl can prepare a skeleton of a cat, or dissect the 
brain of a sheep or cat. Some minute dissection may be at- 
tempted in the laboratory. Most of the exercises involving 
dissection have, however, been given as demonstration work 
for the obvious gain of time by that method. 
The study of bacteria. The work outlined for the study of 
bacterial life will prove of extreme interest to any class in 
Physiology. The chief difficulty to be overcome is sterilizing 
the dishes and the culture medium. This, however, is not in- 
surmountable, the directions having been made as simple as 
possible. It is suggested that three weeks at least in a half- 
year course be devoted to a study of bacteria and disease. 
Reading the directions. Before beginning an experiment 
the directions should be carefully read. The materials and 
apparatus needed should be prepared and assembled. The 
experimenter should have the object of the experiment clearly 
in mind from the beginning. If carried out under well-under- 
stood and carefully controlled conditions, and if the phenom- 
ena are carefully noted, correct conclusions are almost sure to 
follow. 
Preparation for the laboratory period. It is strongly urged 
that every experiment, whether for demonstration by the 4 
LABORATORY MANUAL 
teacher or for class work, be performed by the teacher in 
advance in order that he may be certain of success before 
the pupils, and that everything may pass off without loss 
of valuable time. All the work for the following week, 
for example, may be prepared on a Saturday. There is no 
exercise in this manual which any teacher, no matter how 
little skilled in laboratory work, cannot perform after a trial 
or two. 
The study of the illustrations. The illustrations should be 
carefully studied, as they are intended to elucidate the text 
and not merely to decorate the page. 
Ritchie's Human Physiology, which this manual has been 
prepared to accompany, is rich in clear, instructive illustra- 
tions. This manual is the first to furnish exercises in the in- 
terpretation of illustrations of an elementary textbook. The 
references to the illustrations are introduced at the " psycho- 
logical moment," when the impression gained by the pupil is 
more striking, clear, and lasting than on the first reading of 
the text. Ritchie's Human Physiology is referred to under 
the name Ritchies throughout this manual. 
The pupil's notes. Much of the value of laboratory work 
is lost if the pupil fails to make and keep proper notes. The 
record of the laboratory work should be in drawings and in 
words, as called for in the directions at the end of each exer- 
cise. The drawings should be made on unlined drawing 
paper- sketched with a 3 H pencil and finished with a 6 H 
pencil. Notes should be written in ink. Experiments should 
be written up after the following outline : 
a. Apparatus and material: This may include a sketch of 
the apparatus used. 
b. Procedure: The method of settingup the apparatus and 
performing the experiment. HOW TO USE THIS MANUAL 
5 
c. Observations: A record of the events (phenomena) that 
take place (color changes, rise in temperature, contraction of 
a muscle, etc.). 
d. Conclusions: The "why" of the experiment, the prin- 
ciple learned from the experiment. The conclusion is often 
suggested by questions at the end of the directions. LABORATORY MANUAL 
SECTION I. ORGANIZATION OF LIVING THINGS 
EXERCISE I. MATTER, INORGANIC AND ORGANIC. (CLASS 
work) 
Material: A pebble; quartz or other crystals; pieces of 
iron, cotton, and wool; a living plant; a living animal, such 
as an insect. 
Procedure: Discuss the properties of each object selected. 
After consulting a textbook of Physics, define matter and 
name some of the properties of matter. 
Define living and non-living matter, 
naming appropriate examples. Name 
some of the properties of matter com- 
mon to both living and non-living things. 
Name some of the more obvious properties 
possessed by living things. 
Heat each non-living object mentioned 
above over a flame and note which 
objects char (become black). Charring 
indicates the presence of carbon, a con- 
stituent of organic matter. All organic 
matter is derived from living things. 
Define organic ; inorganic. To what is 
the color of black soil due ? Show how 
coal is organic in its nature. Which 
parts of your desk are organic? Which are inorganic? 
Mention three other organic and three other inorganic 
objects. 
Fig. i. A laboratory blow- 
torch or Bunsen burner. A 
good, pointed flame may 
be made with this. Gaso- 
lineis used as fuel. The 
burner can be set under a 
tripod upon which a vessel 
may be placed. 
Notes: Answer the questions asked in this exercise. Give examples 
with each definition. 
6 ORGANIZATION OF LIVING THINGS 
7 
EXERCISE 2. THE CELL AS THE UNIT OF STRUCTURE OF 
LIVING THINGS. (DEMONSTRATION) 
Experiment a. How to cut a section and mount it for 
microscopic study. 
Apparatus and material: ' Microscope; slides and cover 
glasses; clear water and a pipette; sharp scalpel or section 
razor; elder pith, potato, or other object to be sectioned for 
study; a clean, soft rag such as a threadbare handkerchief; 
dissecting needles ; a pair of forceps. 
Procedure: Clean several slides and cover glasses. The 
cover glasses are easily cleaned if first dipped in alcohol. 
Place a drop of water on a slide. All objects studied should 
be mounted in a liquid medium, usually a drop of water or a 
drop of staining solution. The liquid serves to hold the sec- 
tion in place and to make the object appear somewhat clearer 
to view. 
To cut a section, hold a small block of potato or elder pith 
between the thumb and index finger of the left hand and cut 
the thinnest possible section with a sharp knife or a section 
razor held in the right hand. If the section razor is used, the 
blade may be made to slide over the tip of the middle finger 
of the left hand as the razor is pushed through the object in 
cutting the section. The section may be cut wedge-shaped; 
that is, a little thicker at one end and as thin as possible at the 
other. The section would then taper to almost nothing at 
one edge. It is at this thinnest part that the best view of the 
cells can be had under the microscope. 
Several sections may be cut in this way and placed in the 
drop of water on the slide. With dissecting needles the sec- 
tions are spread out so that a clear view may be had of each 
piece. The cover glass is now dropped over the sections. 8 
LABORATORY MANUAL 
To avoid imprisoning air bubbles, hold the cover glass by one 
edge with a pair of forceps, apply it to the drop of water, first 
at the opposite edge, and then allow it to fall upon the slide 
gradually. A little practice will enable one to do this skill- 
fully. Should the drop of water prove too small to reach to 
the edges of the cover glass, it is not necessary to raise the 
cover glass in order to drive out the air. Apply a small 
drop of water to one edge of the cover glass. The water will 
enter by capillary attraction and the space under the glass 
will be filled. Merely applying the liquid to the edge will 
suffice. If too much water has been added, the surplus may 
be drained off by applying a small piece of absorbent paper 
to the edge. 
The specimen is now ready for study. It is presumed 
that the teacher will manipulate the microscope and focus it 
upon the object for the pupil. The teacher should, however, 
show the pupil how the sections are prepared and mounted 
and how the microscope is manipulated. ■ 
The teacher should teach the names of the important parts 
of the microscope to the pupils : base, pillar, mirror, draw- 
tube, oculars or eyepieces, objectives, stage, diaphragm, 
coarse and fine adjustments. The pupil should understand 
how the light is reflected by the mirror and made to pass up 
through the drawtube and the lenses, and how it illuminates 
the object which is mounted on the slide and placed over the 
hole in the stage. The teacher should emphasize the fact 
that there are objectives of low and high powers. The low- 
power objective is in focus when about one third of an inch 
above the cover glass of the preparation which is being studied, 
whereas the high-power objective, when in focus, is very near 
the object and hence is in greater danger of collision with 
the cover glass. The pupils should be allowed to see the ORGANIZATION OF LIVING THINGS 
9 
same object through both low and high powers in order to 
form a general estimate of their relative magnifying power. 
The following hints will prove helpful: (i) Do not use the 
high power when the low power will suffice. (2) If the high 
power is used, always focus with the low power first, thus 
finding the object and placing it in the center of the field. 
(3) Do not focus down while looking through the instru- 
ment. (4) After turning on the high power turn it down 
so as almost to touch the cover glass. Determine this point 
by placing the eye on a level with the stage of the microscope. 
Then with the eye at the eyepiece, focus up until the object 
comes into focus. 
The teacher should have at hand one or more copies of a 
pamphlet on " How to Use the Microscope," published for 
free distribution by the company whose microscope he uses. 
A wall chart (also free) illustrating the instrument in section 
and in perspective should be owned by the school, as it will 
facilitate the study of the microscope. 
Notes: Sketch the outline of a compound microscope and name 
the parts from the wall chart. Describe how a section is cut and 
mounted for study. 
Experiment b. Pith cells of elder. 
Apparatus and material: As in a, including pith of elder 
or corn. 
Procedure: Make the thinnest possible free-hand section 
of elder or corn pith and mount it in a drop of water as de- 
scribed in a. Study with low and high powers. Note the 
glass-like cell walls. As these cells are dead, the protoplas- 
mic contents are absent. Cork cells may be studied in the 
same way. A very thin section of potato may also be studied. 
Note here also the very thin glass-like cell walls and the 10 
LABORATORY MANUAL 
elliptical or oval starch grains of various sizes within the cells. 
The starch grains are more easily seen than the cell walls. 
Each cell may contain from a few to several dozen starch 
grains (Ritchie, Fig. 61). 
The cells of plants are large and have their thick, stiff walls 
composed of a substance called cellulose, while animal cells 
have thin, flexible walls composed of albumen or they have 
no walls at all, as in the case of the white blood corpuscles 
and nerve cells. That all living things are composed of cells 
is known as the "cell theory." It was first announced in 
1838. On account of the large size and stiff walls of plant 
cells, especially wood cells, the cellular structure of plants 
was first discovered. Soon after this discovery it was found 
that the bodies of animals are also composed of cells. 
Notes: Sketch the cell walls of elder pith, potato, or cork. 
Experiment c. An animal cell. 
Apparatus and material: Microscope and prepared slide 
of ovary of cat or rat; egg of sea urchin or starfish or section 
of liver. 
Procedure: Place a slide under the microscope and select 
one or more typical cells from the specimen. It would be 
well, if more than one microscope is available, to mount 
several typical cells. An egg cell from the ovary of a cat or 
rat or the egg of a starfish is an excellent example. Note 
the nucleus and other parts of the cell. Compare Ritchie, 
Fig. 1, A and B. 
Note: Sketch one or more typical cells and name the parts. 
Experiment d. Cells from the mouth. 
Apparatus and material: Microscope; slide and cover glass ; 
scalpel or other knife; methyl-green solution. ORGANIZATION OF LIVING THINGS 
11 
Procedure: Clean a scalpel and sterilize it by holding it in 
a flame for a moment. Scrape some cells from the inside of 
your own cheek. Smear the scraping on a slide and cover 
with acover glass. Find large, flat cells, hardly visible at first 
on account of their great thinness and transparency. Note 
nuclei. (See Fig. 75, The Human Body and Its Eenmies, 
page 121.) Add a drop of methyl-green solution, which 
stains the nuclei and makes them appear more distinct. (The 
solution will run under the cover glass as soon as the drop 
touches the edge of the glass; the glass need not, therefore, 
be raised to add the solution.) 
Notes: Sketch several flat cells from the mouth as they appear 
under the microscope. 
Experiment e. Paramecium, a one-celled animal. 
Apparatus and material: Microscope; slide and cover 
glass ; 2 °/o acetic acid solution ; 8 % gelatin solution (not abso- 
lutely necessary); culture of Paramecium. 
Procedure: Make a hay infusion or hay "tea" by steeping 
a handful of chopped hay in a pan of warm water. Set it aside 
in a warm place, partly covered with a glass plate to prevent 
too rapid evaporation. Ina few days decay will set in, due to 
the action of the rapidly multiplying bacteria. Later, Para- 
mecia will abound in countless numbers, feeding upon the 
bacteria. The white scum on the surface of the culture will 
be especially rich in the animalcules. 
Mount a drop of the infusion on a slide and note the Pro- 
tozoa (see Ritchie, pages 5 and 285) as well as the bacteria. 
The former will be seen as comparatively large, one-celled 
animals swimming actively about in the liquid. The bacteria 
are very tiny rod-shaped objects swimming about with a zig- 
zag or vibrating movement. 12 
LABORATORY MANUAL 
If mounted in a drop of gelatine solution (about 8 %) which 
is just liquid at room temperature, the swimming of the Para- 
mecia will be retarded and their study greatly facilitated. 
Note the action of the cilia (Ritchie, Fig. 3). After the 
living animals have been studied, kill them by adding to the 
slide a drop of 2 % acetic acid. Note that the cilia are thrown 
out as the Paramecia die from the effects of the acid. 
Notes: Sketch several Paramecia with their cilia. 
EXERCISE 3. REPRODUCTION OF CELLS. (DEMONSTRATION) 
Experiment a. Paramecium. 
Apparatus and material: Same as Exercise 2, e. 
Procedure: In the Paramecium culture described in the 
preceding exercise (2, e) note dividing individuals as shown 
in Ritchie, Fig. 3 ; with a little perseverance a number of these 
will be found. When found, kill with 2 % acetic acid, other- 
wise the individual animalcule to be shown will swim out of 
the field of vision. 
Notes : Sketch a dividing Paramecium. 
Experiment b. Yeast. 
Apparatus and material: Microscope; slides and cover 
glasses; yeast cake; 10% molasses solution; the apparatus 
shown in Fig. 2. 
Procedure: Make a yeast culture as follows: Fill a wide- 
mouthed bottle with 10% molasses solution (10 parts of 
molasses in 90 parts of water) and add to this one fourth of a 
yeast cake. Place -a little molasses solution in a dish and 
invert the bottle in the dish (Fig. 2), taking care that the bot- 
tle remains full. To accomplish this, cover the mouth of the 
bottle with cardboard, hold the cardboard in place while ORGANIZATION OF LIVING THINGS 
13 
inverting the bottle, and remove the cardboard after the inver- 
sion has been accomplished. The mouth of the bottle should 
be raised a little above the 
bottom of the dish by a couple 
of nails or matches. Set the 
culture aside in a warm place. 
At the end of 24 hours study 
the yeast cells in a drop of 
liquid taken from the surface 
or from the bottom of the liquid 
in the dish. Note budding 
yeast cells as shown in Ritchie, 
Fig. 112. The yeast J'cells 
multiply by growing " buds," each of which becomes a new 
yeast plant. 
Notes: Sketch several "budding" yeast plants. 
Experiment c. Cartilage cells. 
Apparatus and material: Microscope and prepared section 
of cartilage tissue. 
Procedure: Study prepared slide of cartilage tissue. Note 
the cells within pockets or lacunae of the tissue. Note that 
some lacunae contain more than one cell; these cells are 
dividing or multiplying. (See Ritchie, Fig. 26.) 
Notes : Sketch several dividing cartilage cells. 
Experiment d. Sea-urchin eggs. 
Apparatus and material: Microscope and prepared slide of 
dividing sea-urchin or starfish eggs. 
Procedure: Study prepared slide of dividing sea-urchin 
eggs, showing 2-, 4-, 8-, 16-, 32- and more cell stages. 
Every animal or plant begins as a one-celled form ; namely, 
from an egg produced by the mother plant or animal. This 
-GAS 
molasses 
SOLUTION 
"yeast 
Fig. 2. The fermentation of molasses 
by yeast plants. See Exercise 3, b. 14 
LABORATORY MANUAL 
cell multiplies, in higher forms, until the complex body of 
the plant or animal results. (See Ritchie, page 6.) 
Notes : Sketch eggs in different stages of division. 
EXERCISE 4. ARRANGEMENT OF CELLS INTO TISSUES. 
(demonstration) 
Experiment a. Cartilage tissue. 
Apparatus and material: Microscope; prepared slide of 
cartilage tissue (as in Exercise 3, c); also, if desired, fresh 
cartilage from the end of a bone; sectioning knife or razor; 
slides and cover glasses. 
Procedure: Study the preparation of cartilage tissue. 
Note that the tissue consists of cells and the ground substance 
between the cells. (See Ritchie, Fig. 26, a and 
It is instructive also to study a fresh specimen of cartilage 
tissue. Cut a free-hand section of cartilage from the end of 
a long bone, eg. of a "drumstick." The femur of a frog 
soaked in alcohol or formaldehyde will do very well. Study 
the section mounted in a drop of water or dilute alcohol; 
compare with the stained preparation. (Study Ritchie, page 
59, footnote.) 
Notes : Make a drawing of cartilage tissue. 
Experiment b. Connective tissue. 
Apparatus and material: Microscope ; slides and cover 
glasses ; dissecting instruments; Ringer's solution ; methyl- 
green solution; dead mouse; piece of-ligament from back 
of neck of ox. 
Procedure: How to kill an animal: Under no circumstances 
should an animal be experimented upon alive or tortured in 
any way. When the experimenter is ready, the animal ORGANIZATION OF LIVING THINGS 
15 
should be killed by chloroforming it. Select an air-tight box 
or a glass or earthenware jar suitable to the size of the 
animal. A five-gallon jar is a good size for a chloroforming 
jar. Drop a rag or tuft of cotton saturated with chloroform 
into the bottom of the jar. Then place the animal in the 
jar and cover it. The animal will soon be dead. 
Cut off and skin the tail of the mouse. Long white ten- 
dons are now visible running along the tail. Pull off a tendon 
with a pair of forceps and place it in a drop of water on a 
slide. With dissecting needles tease out the tendon, i.e. tear 
it apart into fine shreds. Cover the preparation with a cover 
glass and study the tissue under the microscope. Note the 
fibers. Tease out another bit of tendon in methyl-green. 
Are cells now visible in such a stained preparation ? (See 
Ritchie, page 8.) The tendon just studied is white connective 
tissue and is inelastic, i.e. it will not stretch, as may be dem- 
onstrated with a piece of the loose tendons from the leg of an 
ox or a pig. Elastic (yellow) connective tissue may be taken 
from the large ligament found in the neck of cattle. This 
ligament is called the ligamentum nucha. It serves to hold 
up the head. Being elastic, it stretches when the animal 
wishes to lower the head, as when grazing. Obtain a piece 
of this ligament from a butcher. Demonstrate its elastic 
qualities. If desired, a bit of this tissue may be treated and 
studied as described above for the preparation of a tendon 
from the tail of a mouse. The connective tissue layer under 
the skin and the connective tissue framework of most of the 
tissues and organs contains an admixture of yellow elastic 
fibers. 
Notes: Sketch connective tissue and show how the footnote, Ritchie, 
page 59, applies to this tissue. 16 
LABORATORY MANUAL 
Experiment c. Epithelial tissue. 
Apparatus and material: Microscope; prepared slides of 
skin, of trachea or esophagus and of stomach or intestine. 
Procedure: In epithelial tissue the cells are arranged like 
the bricks of a pavement. In some organs the epithelial tissue 
serves to cover surfaces; as, e.g. in the outer skin (Ritchie, 
Figs. 5, 93, 94, 96, 113, 116). In other organs the tissue 
lines cavities (Figs. 6, 47, 49, 51, 55, 76). These figures should 
be studied by the class before the slides are studied. The 
teacher will then focus the microscope on the epidermis of 
the skin, on the lining of the trachea (or the esophagus), and 
on the lining of the stomach (or the intestine). Note that 
epithelial tissue of the skin is many cells thick and that of the 
stomach and intestine only one cell thick. 
Notes: Sketch a portion of each organ studied, showing the 
epithelial tissue.- 
Experiment d. Muscle tissue. 
Apparatus and material: Microscope; slides and cover 
glasses ; dissecting needles ; Ringer's solution ; small piece of 
muscle from breast of cooked 'chicken; also portion of mus- 
cular wall of chicken's gizzard. 
Procedure: Pull out a very small bundle of muscle from 
the breast of the chicken and tease out the specimen into the 
finest possible shreds. Study it under the high power of 
the microscope. Can you see the muscle fiber with its cross 
stripes as represented in Ritchie, Fig. 35, Bl 
Treat the muscle from the gizzard in the same manner. 
The muscle fibers here do not exhibit cross stripes; they 
are smooth (unstriped) or involuntary muscle fibers. Can 
you find muscle cells as shown at the top of Ritchie, Fig. 5 ? 
Explain how the cells fit together to make a tissue. ORGANIZATION OF LIVING THINGS 
17 
Notes: Sketch several muscle fibers of each kind, as seen. Tell 
where each kind of fiber is taken from and describe how it was pre- 
pared for study. 
Experiment e. Nerve tissue. 
Apparatus and material: Same as in preceding experiment, 
substituting a nerve of some animal for a muscle. 
Procedure: A nerve may be found as a shining white 
cord, not so glistening or so tough as a tendon, in the flesh of 
any animal. Tease out a portion of a nerve on a slide and 
study it. Note the nerve fibers. No cells will be seen, for a 
nerve consists of fibers only, the cells being situated in central 
stations called ganglia or in the brain or spinal chord. (See 
Ritchie, Fig. 15.) The nerve cell could be studied in a pre- 
pared section of one of these organs. 
Notes: Sketch a nerve which has been torn apart to show the 
fibers. 
EXERCISE 5. ARRANGEMENT OF TISSUES INTO ORGANS. (CLASS 
WORK) 
Experiment a. A muscle. 
Material: A small muscle, such as a muscle of a toad or a 
frog; dissecting needles. 
Procedure: Dissect a muscle and note as many kinds of 
tissue as you can. (Cf. Ritchie, Figs. 35 and 36.) 
Notes: Describe this experiment and make a list of the tissues 
found. 
Experiment b. Other organs. (Home work.) 
Material: Ritchie, Figures 49, 91, and 93-96. 
Notes: From a study of the appropriate figures in Ritchie make a 
istof tissues that enter into the formation of the stomach, the kidney, 
and the skin. 18 
LABORATORY MANUAL 
EXERCISE 6. PLAN OF THE BODY. ARRANGEMENT OF ORGANS. 
(class work) 
Experiment a. A simple plan : Hydra. 
Apparatus and material: Microscope, and prepared cross 
section of hydra. 
Procedure: Study a cross section of a hydra under the low 
power of the microscope. Note the ring of cells. This is the 
wall of the animal, which consists merely of a hollow sack, 
attached at one end and open at the other. 
For further studies of the Hydra consult a textbook of 
Zoology. 
Notes: Sketch a cross section of the Hydra. 
Experiment b. The double-tube plan : the earthworm. 
Apparatus and material: Microscope ; hand lens ; and pre- 
pared cross section of an earthworm. 
Procedure: Study the cross section of an earthworm under 
a hand lens and under the microscope. Note the body wall 
(largely muscular) on the outside and the intestine on the 
inside. The latter is suspended from the wall above by a mes- 
entery. The space between the body wall and the intestine 
is the body cavity. The plan of structure of the earthworm 
is thus that of a tube within a tube. 
Study Ritchie, Fig. 9, and note how the human body con- 
forms to the general "double-tube" plan of structure. 
Experiment c. Exo-skeleton and endo-skeleton. 
Apparatus and material: Insects, such as grasshoppers, 
crickets, or cockroaches; a frog or toad; dissecting instru- 
ments; dissecting boards or pans; killing jar or box; chloro- 
form. What insect is used depends upon the season of the ORGANIZATION OF LIVING THINGS 
19 
year. In spring and fall grasshoppers are available; in 
winter cockroaches may be caught in grocery stores, bakery 
shops, and other places, especially at night. Toads may be 
found at night in gardens or on lawns, and frogs may be 
captured about springs or ponds at certain seasons. 
Procedure: The toad or the frog may be skinned thus: 
slit the skin lengthwise from the jaw back. Then slit it 
across the middle of the body. The skin may now be pulled 
off like a glove. Cut off a leg of an insect and a leg of a 
frog. Study the cut ends. Note that the insect has the 
skeleton on the outside and the muscles on the inside. Com- 
pare the condition in the frog with that in the insect. Feel 
your own arm and note the relation of bone to muscle. (See 
Ritchie, Fig. 39.) 
Study Ritchie, Fig. 9. Note that the intestines are in the 
ventral cavity, and that the spinal cord and brain (central 
nervous system) are on the dorsal side. (See Ritchie, 
page 16, footnote.) 
Lay the frog on its back and open the body cavity by 
slitting open the ventral wall of the abdomen. Note the 
intestine. Find the backbone. Turn the frog over and cut 
open the backbone, exposing the spinal cord. (Do not in- 
jure the spinal cord, for the same specimen should be 
used again.) It is thus seen that the frog, as well as the 
human being, has the central nervous system dorsal to the 
intestine. 
Lay the cockroach or grasshopper on its ventral surface in 
a dissecting tray. This is sometimes best done with enough 
water in the tray to cover the insect, worm, etc. The insect 
may be fastened to the beeswax by pins. With a pair of 
scissors cut off the dorsal wall, thus exposing the intestine 
and other organs in the body cavity. Push them aside and 20 
LABORATORY MANUAL 
note the " nerve chain " on the ventral surface. The nerve 
chain is seen to consist of nerve fibers and a series of ganglia, 
or knots of nerve tissue. It is thus found that the insect 
has the nervous system ventral to the intestine. 
Notes: Sketch a longitudinal section of a frog after the plan of 
Ritchie, Fig. 9, and beside it place a sketch of a similar section of 
the insect. Let each drawing show *body wall, skeleton, nerve chain, 
and intestine. 
EXERCISE 7. THE CLASSIFICATION OF VERTEBRATES. (HOME 
work) 
Experiment a. The classes of vertebrates. 
Reduce the diagram, Ritchie, Fig. 11, to outline form, adding 
to the outline the characteristics of the five great classes of 
vertebrates according to footnote, page 18. To what class 
oes man belong ? Why ? 
Experiment b. Comparison of man with other mammals. 
Material: Illustrations in Ritchie ; a textbook in Zoology ; 
skeletons or parts of skeletons of various animals brought 
into the laboratory by the pupils. 
Notes: Write out a comparison of man and other mammals as to : 
(1) The position of the axis of the body. (2) The various means 
of locomotion among mammals and the resulting differences in fore 
and hind limbs. (See Ritchie, Fig. 33.) Why are the fore and hind 
limbs much alike in the horse but different in man, the bat, the whale, 
and the kangaroo. (3) The elimination of the tail as a functional 
organ. (4) The increase of the hemispheres of the brain. (5) The 
change of facial angle. (Cf. Ritchie, Figs. 17 and 32.) The study of 
the classification of mammals may be pursued further by reference 
to textbooks on Zoology. ORGANIZATION OF LIVING THINGS 
21 
EXERCISE 8. GENERAL VIEW OF THE NERVOUS SYSTEM. 
(demonstration) 
{To illustrate Ritchie, Chapter III) 
Experiment a. The central nervous system. 
Apparatus and material: The toad used in Exercise 6, c, 
above; dissecting instruments. 
Procedure: Continue the dissection of the nervous system 
as begun in Exercise 6, c, by cutting away enough of the 
vertebrae on the dorsal side of the animal to show the entire 
spinal cord. Remove also the roof of the skull, exposing the 
brain. A strong pair of fine-pointed scissors will be found 
useful for removing the bone, piece by piece. The dissection, 
if well done, should be preserved in 5 % formaldehyde and 
kept from year to year. The covering of the vessel may 
be sealed with paraffin to prevent evaporation of the 
formalin. 
Notes: Sketch the central nervous system (brain and spinal cord) 
of the frog. 
Experiment b. The sympathetic nervous system. 
Apparatus and material: The toad used in the preceding 
experiment; dissecting instruments. 
Procedtire: Remove all the viscera of the animal. Lay it 
on its back. The dorsal wall of the ventral cavity is now in 
view. A careful search will disclose a chain of ganglia con- 
nected by nerves lying close against the dorsal wall of each 
side of the ridge which marks the spinal column. These 
two nerve chains with their fibers belong to the sympathetic 
nervous system (Ritchie, Fig. 105). 
Notes : Sketch the sympathetic nerve chains of the frog. 22 
LABORATORY MANUAL 
Experiment c. Reflex action. 
Apparatus and material; Frog or toad, recently killed; 
10% acetic acid. 
Procedure: Stretch the hind leg of the frog and let go ; 
the leg is drawn up. Touch the hind foot with a drop of 
10% acetic acid; the foot is withdrawn. Touch the chest 
with a drop of acid. What is the result ? 
Notes: Describe several experiments illustrating reflex action. 
Experiment d. Function of a nerve. 
Apparatus and material: The frog or toad used in the 
preceding experiment; a glass rod; the apparatus shown in 
Fig. 6. 
Procedure: Lay bare the sciatic nerve as described in 
Exercise 22, a. Stimulate the nerve (1) by pinching it at a 
point as far from the foot as possible. What is the result ? 
Stimulate the nerve (2) by touching it with a hot iron. 
Stimulate the nerve (3) by applying an electric current from 
a dry cell. Do you observe any change in the nerve on stimu- 
lation ? What is the function of a nerve ? Of what is a nerve 
composed ? (Review Exercise 4, e, and see Ritchie, Fig. 15.) 
Name the three kinds of stimulation employed in this experi- 
ment to stimulate the nerve. 
Notes: Answer the questions asked in this exercise. Describe 
how the experiments were performed, drawing figures where 
necessary. SECTION II. THE ORGANS OF LOCOMOTION 
EXERCISE 9. THE SKELETON. (CLASS WORK) 
Experiment a. The human skeleton. 
A human skeleton should be studied in connection with 
Ritchie, Chapter IV. If the school does not possess a speci- 
men, it may be possible to borrow one from a physician of 
the community. Study advanced textbooks for suggestions. 
It will be well for the teacher to lecture to the class on the 
parts of the skeleton and their uses and peculiarities, illus- 
trating each point by reference to the skeleton. A definite 
knowledge of the most important things to be noted in the 
skeleton may thus be acquired in a few periods. 
Experiment b. Skeleton of a cat. 
It is possible to illustrate many important features by using 
the skeleton of a mammal, such as the cat. To prepare a 
skeleton : Kill the cat by chloroforming it, skin it, remove the 
viscera without injuring the chest bones, and cut off all the 
flesh possible with a scalpel and scissors. Then boil the ani- 
mal for a short while in the following " liquid soap " mixture : 
water 2000 c.c.; ammonia, 150 c.c.; saltpeter, 12g.; laundry 
soap, 75 g. Boil the skeleton until the muscles have softened 
but the ligaments still hold together. If it is desired to dis- 
articulate the skeleton, the bones must be boiled longer. It 
may be well to disarticulate the head and limbs before boiling. 
To prevent the vertebral column from coming to pieces, the 
vertebrae may be " strung " on a strong piece of twine or on 
a wire which is run through the neural canal. With patience 
any pupil may make an excellent preparation of a skeleton. 
The pupils should be encouraged to bring the skeletons 
of various small animals. The school may thus easily 
acquire specimens of all the vertebrate limbs shown in 
Ritchie, Fig. 33. 
23 24 
LABORATORY MANUAL 
EXERCISE 10. OBSERVATIONS ON THE SKELETON. (CLASS 
work) 
Experiment a. Classification of the bones. 
Material: A skeleton. 
Procedure : On the human skeleton study the bones named 
in Ritchie, Chapter IV, and especially in Fig. 16. If only the 
skeleton of the cat is available, make out all the correspond- 
ing bones of the cat. Classify every bone (i) according to 
shape and (2) according to use. 
Notes: Make a list of classes of bones (long, short, flat, etc., or 
for protection, motion, etc.), and under each class a list of bones com- 
ing under that class. Use the names of bones givenhn Ritchie, Figs. 
16 and 17. 
Experiment b. Comparison of human limbs with limbs of 
other vertebrates. 
Material: Bones of animals ; disinfectant, such as formalde- 
hyde or corrosive sublimate. 
The ingenuity and enterprise of the pupils can be relied 
upon to bring in or prepare, according to Exercise 9, b, 
material for this study. If bones of dead animals are brought 
in from the fields, they should be thoroughly scrubbed with 
5 °Jo formaldehyde solution or a saturated solution of corrosive 
sublimate, or disinfected by being boiled in water, before be- 
ing handled by the class. Greasy bones may be cleansed by 
boiling in strong soapy water. 
Procedure: As many comparisons as possible should be 
drawn between human limbs and those of the animals repre- 
sented in the collection. If such material is not at hand, the 
living bird (chicken, etc.), horse, cow, frog, mole, or bat may 
be compared with the human body. 
Notes: Write out as many comparisons between the limbs of vari- 
ous animals and those of man as time will permit. THE ORGANS OF LOCOMOTION 
25 
Experiment c. Comparison of the upper and the lower limbs 
of man (Home work.) 
Material: Observations on one's own body; a skeleton 
would prove helpful. 
Procedure: Point out the differences in structure and in 
use of the arms and legs. Show how the legs are adapted 
to carry the weight and note that the arms have freedom of 
motion rather than strength. Compare the shoulder joint 
with the hip joint; the elbow with the knee; the ankle with 
the wrist; the upper arm with the thigh ; the forearm with 
the shank; the foot with the hand. 
Notes: Write up the observations made. 
Experiment d. The articulation of the vertebrae with one 
another. 
Material: Several successive vertebrae. 
Procedure: Select several successive vertebrae, as in 
Ritchie, Fig. 21, and make out the manner of interlock- 
ing of vertebrae. What are the functions of the various 
processes of the vertebrae? (Study Ritchie, Figs. 21, 41, 
and 42.) 
Notes: Make a drawing similar to Ritchie, Fig. 21, but draw from 
the objects, do not copy the drawing. 
Experiment e. The rotation of the hand. 
Material: Skeleton. 
Procedure: Make out how it is possible for us to rotate the 
hand, i.e. to turn it palm up or palm down. Note rotation 
of radius at its pivot joint at the elbow. (See Ritchie, 
Fig. 33, ^.) 
Notes: Describe the observations made in this exercise. 26 
LABORATORY MANUAL 
EXERCISE II. THE STRUCTURE OF THE BONES. (CLASS 
WORK) 
Experiment a. A long bone. 
Material: A femur or humerus of a dog or pig or the 
" drumstick " of a chicken ; a fine hacksaw. 
Procedure: Saw the bone lengthwise as shown in Ritchie, 
Fig. 25. Saw also a cross section of the shaft. Perform 
the experiments described in Ritchie, page 41. 
Notes: Make drawings of the longitudinal and the cross section 
of a long bone. Write up the experiments to show why the shaft is 
hollow. 
Experiment b. A flat or irregular bone. 
Material: A rib or a vertebra. 
Procedure: Compare a cross section of the shaft of a long 
bone with a similar section of a rib or a vertebra. Compare 
the red and the white marrow. 
Notes : Sketch a cross section of a rib. 
EXERCISE 12. STRUCTURE OF BONE TISSUE. (CLASS WORK) 
Apparatus and material: Microscope; prepared slide of 
bone tissue. If it is desired to prepare the sections in the 
laboratory, the following things are needed : long bone of 
dog or cat; fine hacksaw, whetstone, and water. 
Procedure: Study the sections of bone tissue with the 
microscope. Use as a guide, Ritchie Fig. 23. Fig. 23, A, 
shows the canals both in cross section and longitudinal sec- 
tion. Find the canals and the lacunae surrounding them. 
The lacunae are the homes of the bone cells. Turn on the 
high power and compare the view with, Fig. 23, B. 
To prepare sections of bone, proceed as follows : Saw the THE ORGANS OF LOCOMOTION 
27 
thinnest possible cross section from the end of the bone and also 
a similar longitudinal section. These pieces are still far too 
thick for study. Grind them down on a whetstone. Place a 
section on the stone, add a little water, and then rub with the 
finger until the section is very thin, when it is ready for study. 
Notes: Sketch a cross section of bone tissue as seen under the 
microscope. 
EXERCISE 13. MATERIALS IN BONES. (CLASS WORK) 
Material: A long bone, e.g. a drumstick; 5-10 % hydro- 
chloric acid. 
Procedure : Perform the experiments as directed in Ritchie, 
page 39. 
Notes : Explain the results obtained. 
EXERCISE 14. USES OF OTHER SKELETAL TISSUE. (CLASS 
work) 
Experiment a. Connective tissues. 
Material: The hip joint of a frog or toad and several long 
muscles with their tendons. (These specimens may be pre- 
served in 5 % formaldehyde from year to year.) 
Procedure: Study the ligaments by which the bones are 
held together at the hip joint. Review Exercise 5, a. Study 
the tendons of the muscles and follow them as far as possible 
into the body of the muscle. An examination of a tendon 
with the point of the muscle joining it is instructive. 
Notes : State the chief functions of connective tissue. 
Experiment b. Cartilage. 
Material: Human skeleton or separate bones of cat, frog, 
chicken, or other animal; hip joint used in preceding experi- 
ment. 28 
LABORATORY MANUAL 
Procedure: Illustrate the uses of cartilage by pointing out 
(i) the smooth, tough capping for long bones (Ritchie, 
Fig. 25); (2) the lining of articular facets or sockets 
(Ritchie, Fig. 27); (3) the connection of ribs and sternum 
(Ritchie, Fig. 19) ; (4) the packing between vertebrae (Ritchie, 
Fig. 21). Also feel your own nose and ear, which are made 
stiff (but flexible) by means of cartilage. 
Notes: State the uses of cartilage in the body. 
EXERCISE 15. KINDS OF JOINTS. (CLASS WORK) 
Material: A skeleton. 
Procedure: a. Sutures of the skull. A skull of a cat or other 
animal will do very well to illustrate this class of joint. Note 
how firmly the bones are knit together. (Cf. Ritchie, Fig. 17.) 
Gliding joint. Study the articulation of two successive 
vertebrae (Ritchie, Fig. 21). How much motion is possible 
between vertebrae? Study also the wrist and ankle joints. 
c. Hinge joint. Study the knee joint; also the articula- 
tion of the ulna and the humerus at the elbow. The elbow 
has two distinct joints. 
d. Ball-and-socket joint. The hip and the shoulder are 
examples of this class. The former may be studied in detail 
(see below). 
e. Pivot joint. Review Exercise 10, e above. If the hu- 
man skeleton is not available, demonstrate the rotation of the 
radius in your own arm. Flex the right arm at the elbow, 
holding the forearm horizontal. Press upon the radius near 
the elbow with the fingers and, as you rotate the hand alter- 
nately palm up and palm down, observe that the radius rotates 
at the elbow and that the ulna remains stationary. 
Notes : Name the classes of joints, give examples of each, and state 
the motion each allows to the articulating bones. THE ORGANS OF LOCOMOTION 
29 
EXERCISE 16. STRUCTURE OF A BALL-AND-SOCKET JOINT. 
(class work) 
Material: A hip joint of a pig from the butcher. 
Procedure: Study Ritchie, Fig. 27. The upper larger 
drawing shows the " capsular " ligament. Cut this partly in 
two in the specimen, so as to expose the inner structure of 
the joint. Note the smooth, moist surfaces. What parts do 
cartilage and connective tissue play in a joint? Find the 
round ligament (compare lower drawing, Fig. 27). 
Notes: Describe a joint either in words or by drawings. 
EXERCISE 17. PROTECTION OF THE BRAIN. (HOME WORK) 
Material: The sticks shown in Ritchie, Figs. 28, 30, and 
31; a human skeleton. 
Procedure: Perform the experiments as illustrated by 
Ritchie, Figs. 28-31. Compare Fig. 31 with the curvatures 
of the spinal column. Compare Ritchie, Figs. 18 and 31. 
Study also Ritchie's Primer of Physiology, pages 33-37. 
Notes: Write several paragraphs showing how tight, high-heeled 
shoes injure the arch of the foot. 
EXERCISE l8. FRACTURES AND SPRAINS. (CLASS WORK) 
Material: Pillow; wooden sticks about two feet long; 
pieces of rope; X-ray pictures of fractures. 
Procedure: After having studied page 55 in Ritchie, the 
subject may be pursued further in the Red Cross abridged 
textbook on First Aid to the Injured. The pillow splint should 
be demonstrated to the class, one of the boys acting as subject. 
(See Fig. 239, The Human Body and its Enemies.') X-ray 
pictures of fractures, borrowed from a physician or taken from 30 
LABORATORY MNAU AL 
a magazine, may be shown to the class. (When once acquired, 
these pictures should be saved from year to year.) 
Notes: Describe a pillow splint as applied in the demonstration. 
EXERCISE IQ. LEVERS OF THE BODY. (HOME WORK) 
Apparatus: A ruler for a lever; any other objects for ful- 
crum and weight: a pair of scissors, a nutcracker, a pair of 
sheep shears, one's own body. 
Suggestions : Since the larger movements of the body are 
brought about by the action of muscles in connection with 
FIG. 3. The arrangement of fulcrum, weight, and power in the three classes of levers. 
To the right, common examples of the use of levers in mechanical appliances. 
bones, the latter are said to serve as levers. Examples of the 
three classes of levers recognized in mechanics are found in 
the human body. If time permits, the teacher may construct 
an interesting series of exercises by having the class find ex- 
amples in the body of each class of lever. Figure 3 and the 
following suggestions may be helpful: 
A lever of the first class has the fulcrum (F) between the 
power (F) and the weight ( W}. Example: pair of scissors. THE ORGANS OF LOCOMOTION 
31 
Example from body: striking table with fist. Consult Ritchie, 
Fig. 39. In striking the table, the power is applied by the 
triceps muscle to the end of the ulna of the forearm, the 
elbow joint is the fulcrum, and the weight is the hand. 
A lever of the second class has W between P and F. Ex- 
amples: nutcracker, wheelbarrow. Example from body: 
rising on toes. Here the weight is the body, the fulcrum is 
at the toes, and the power is applied to the heel bone by the 
muscles at the calf of the leg. (Cf. Ritchie, Fig. 29.) 
A lever of the third class has P between F and IF. Ex- 
ample: sheep shears. Example from body: holding weight 
in the hand. 
Procedure: Place the ruler in position to represent a lever 
of each of the three classes described above. Study the 
levers involved in the scissors, nutcracker, and sheep shears. 
Study the levers of the body as indicated above. Determine 
also the class of lever involved in the following movements : 
nodding, bowing, curtseying, standing on heels, tapping floor 
with toes, pressing index finger and thumb together, kicking, 
raising leg from lying position. 
Notes: Sketch Ritchie, Fig. 29, A, and indicate the P, F, and W 
in the drawing. Appropriate sketches may be made of the parts 
involved in the movements of the limbs stated in the procedure 
above. Indicate the P, F, and W in each case. 
EXERCISE 20. A STUDY OF TENDONS. (CLASS WORK) 
Experiment a. The long tendons (" leaders ") of the foot and 
the hand. 
Material: Foot of a bird; the human hand. 
Procedure: One of the pupils might dissect out the foot 
and drumstick of a bird, following several tendons from their 32 
LABORATORY MANUAL 
muscles in the shank to their attachment in the foot. Such 
a specimen should be preserved for future use. 
Hold your hand out before you, palm down; move the 
fingers in every way possible, noting the action of the ten- 
dons as seen under the skin. Compare Ritchie, Fig. 37. 
Notes: Sketch several tendons in the foot of some animal. 
Experiment b. Illustrating the action of a tendon. 
Material: A piece of string; one's own hand. 
Procedure: Perform the experiment described in Ritchie, 
page 65. 
Notes: Answer the questions asked in directions, Ritchie, page 65. 
EXERCISE 21. STRUCTURE OF A MUSCLE. (CLASS WORK.) 
Material: A long tapering muscle of a cat or a frog, 
soaked for several days in 1 % formaldehyde or in 30% alco- 
hol or softened by boiling in water. 
Procedure: Cut the muscle as represented in Ritchie, 
Fig. 35, A. Note the bundles as shown. With dissecting 
needles tease the muscle apart, beginning at the tendon. 
The object of this exercise is to show that the " connective 
tissue skeleton " of the muscle (Ritchie, page 63) is continuous 
with the tendons at the ends, as shown in Ritchie, Fig. 36. 
Notes: Discuss the reason why a round steak cut near the end 
of a muscle is tougher than that cut from the middle of a muscle. 
EXERCISE 22. THE WORK OF MUSCLES. (DEMONSTRATION) 
Experiment a. How to make a muscle-nerve preparation. 
Materials: Living frog or toad ; chloroform ; dissecting 
set, including a strong pair of scissors; a board about 6 by 10 
inches; a small piece of sheet rubber; normal salt solution, THE ORGANS OF LOCOMOTION 
33 
three tacks, hammer, string, a pm bent into a hook, a weight 
(a tenpenny nail will do for a weight). 
Procedure: Kill the frog or toad by chloroforming it (see 
Exercise 4, b). Cut off the head. Slit open the ventral cavity 
and remove the entrails, saving the heart 
for Exercise 23. (This experiment 
should be begun at once, as the heart 
will continue to beat for some time.) 
Remove the skin of the frog. To do 
this, simply make a circular incision 
through the skin around the body and 
then pull the legs out of the skin as 
one would pull the fingers out of a tight- 
fitting glove. Cut off the upper two 
thirds of the trunk. There now remain 
only the pelvis and the hind legs. 
Split the pelvis in two lengthwise. 
Each of the two halves with its attached 
leg will furnish a preparation. While 
experimenting with one, the other should 
be covered with cotton soaked in 
normal salt solution until the experi- 
menter is ready to use it. 
In the thigh of the frog's leg find the 
sciatic nerve by the aid of Figure 4. 
The nerve will be found together with 
the femoral artery and vein under the 
narrow, band-like biceps muscle (Fig. 
4, or in the furrow Push aside 
the muscle or cut it away, exposing the 
nerve, a white strand accompanying the 
blood vessels mentioned. Free the nerve 
Fig. 4. The right leg of a 
frog, with the skin removed. 
VE and SM, large muscles 
of the thigh; B, biceps 
muscle; F, furrow in which 
the femoral artery, the fem- 
oral vein, and the sciatic 
nerve are found (usually 
under the biceps muscle) ; 
G, the gastrocnemius mus- 
cle, used in the experi- 
ments; 1, its tendon (ten- 
don of Achilles); 3, the 
patellar ligament; tacks are 
driven through points 2, 3, 
and 4 in mounting the leg 
on a frog board. (See also 
Fig. 5-) 34 
LABORATORY MANUAL 
with a pencil point. Insulate the nerve by slipping under 
it a small piece of sheet rubber. 
The preparation is now ready for stimulation, but it may 
first be mounted on a board, as shown in Fig. 5. Drive tacks 
through the points shown (i.e. at 2, 3, and 4, Fig. 4), es- 
pecially through 
the tendon at the 
knee. Cut the 
tendon of the 
gastrocnemius 
muscle (Fig. 4, G) 
loose at the lower 
end (Fig. 4, 1), 
leaving as much 
of the large ten- 
don attached to 
the muscle as 
possible. By 
meansof ahooked 
pin and a string 
a weight may be 
attached to the 
tendon. The 
preparation may 
now be mounted 
vertically, as shown in the illustration (Fig. 5). When the nerve 
is stimulated, the muscle will contract and raise the weight. 
Caution : The nerve should be kept constantly moist with 
normal salt solution. 
VE 
Rubber 
InsulatioN 
Support 
SM 
NERVE 
GASTROCNEMIUS 
MUSCLE 
WEIGHT 
BOARD 
Fig. 5. Method of mounting a frog's leg on a board. Num- 
bers and letters are the same as in Fig. 4. The biceps 
muscle has been removed and the sciatic nerve exposed. 
Notes : Sketch the leg of a frog, showing the gastrocnemius muscle 
and the sciatic nerve. THE ORGANS OF LOCOMOTION 
35 
Experiment b. How to stimulate the nerve. 
Apparatus and material: The muscle-nerve preparation just 
described; the electric apparatus shown in Fig. 6. (See 
legend under figure.) 
Procedure: It is readily seen from a study of Fig. 6 that 
if the connection is made between the tips of the wires of the 
electrode, the circuit is completed, and the electric current 
SEALING WAX PLUGS 
DRY CELL 
-TIPS OF WIRES 
GLASS TUBES. TIED TOGETHER FOR HANDLE 
INSULATED COPPER WIRE 
Fig. 6. Electrical apparatus for stimulating the nerve. The wires from the electrical 
dry cell are passed through glass tubes and allowed to protrude for about J inch .at the 
other end. The wires may be sealed in place with sealing wax and the glass tubes tied 
together for a handle. No current passes until the ends of the wires are connected; as 
for example, when the ends of the wires are touched to the nerve. 
will run through the wires. On touching the nerve with the 
tips of the wires, therefore, the current will enter the nerve 
and stimulate it. A muscular contraction should follow the 
stimulation. 
If the experiment is not successful at first, bring the wire 
tips closer together. If still unsuccessful, the current is, per- 
haps, not strong enough to pass through the nerve ; in which 
case, use two dry cells, connecting the carbon of one with the 
zinc of the other. 
Review in this connection Exercise 8, d. 
Notes: State some of the functions of nerves. Describe an experi- 
ment to show that stimulation of the nerve causes contraction of the 
muscle to which it passes. 36 
LABORATORY MANUAL 
Experiment c. Tetanus. 
Apparatus and material: The same as in the preceding ex- 
periment. 
Procedure: Touch the nerve frequently in as rapid succes- 
sion as possible, or arrange a small vessel of mercury in the 
circuit, and then make and break the circuit by quickly 
dipping the end of one of the wires into the mercury and 
withdrawing it. A continuous contraction of the muscle re- 
sults if the stimuli are in sufficiently rapid succession. This 
continued contraction is called tetanus. The muscle does not 
have time to relax before the next impulse to contract comes 
on. 
Notes : Look up the word " tetanus " in the dictionary. The word is 
also used as the name of the disease, tetanus or lockjaw (Ritchie, page 
313); State the reason why the name of the disease should be taken 
from the name of the phenomenon of tetanus in muscles. 
Experiment d. Fatigue. 
Apparatus and material: Same as in b above. 
Procedure : Stimulate the muscle once each second until the 
muscle becomes exhausted. This phenomenon of exhaustion 
is called fatigue. Cut the muscle across and test it for acidity 
with litmus paper. 
Notes: Describe an experiment of your own, showing how a muscle 
of your arm may become fatigued. How does it recover from fatigue ? 
EXERCISE 23. RHYTHMIC CONTRACTION. (DEMONSTRATION) 
Apparatus and material: Heart of a frog; small, shallow 
vessel containing Ringer's solution at ordinary temperature; 
a quantity of ice-cold Ringer's solution and a quantity of hot 
Ringer's solution. 
Procedure: Place the frog heart in Ringer's solution at THE ORGANS OF LOCOMOTION 
37 
ordinary temperature. Note the beating of the heart. Slowly 
add ice-cold solution to the liquid containing the heart. Then 
slowly add hot solution so as gradually to warm the liquid 
containing the heart. Note the effect of temperature on the 
rate of the heartbeat. 
Notes: Describe the effect of temperature on the contraction of the 
heart. Does temperature have this effect on the voluntary muscles ? 
How do you know this? 
EXERCISE 24. MODEL OF ARM. (DEMONSTRATION) 
Apparatus and material: The apparatus shown in Fig. 7, 
including two muscle-nerve preparations of a frog; the elec- 
trical apparatus shown in Fig. 6. 
Fig. 7. Model of arm, made of three pieces of thin board and two muscle-nerve 
preparations. 
Procedure: The purpose of this experiment is to show the 
antagonistic action of muscles. Construct the model shown 
in Fig. 7, which is one half natural size. A, B, and C are thin 
pieces of wood {e.g. sides of a cigar box) hinged together as 
shown. M and M' are muscle-nerve preparations prepared as 
directed above (Exercise 22, a), but the shank of the leg is cut 38 
LABORATORY MANUAL 
off below the knee. One end of each muscle-nerve prepara- 
tion is tacked to A. The free tendon T of the muscle is 
tacked to C directly, or, if the muscle is too short, the tendon 
is tied to C by means of a string (3). The nerves N and N' 
passing to TZand M' are insulated. The muscles are made 
to contract by stimulating the nerve with an electric shock, as 
in Exercise 22. Stimulate N and N' alternately. Compare 
the result with the action of the biceps and the triceps of the 
human arm. One of the muscle-nerve preparations would rep- 
resent the biceps and the other the triceps (Ritchie, Fig. 39). 
Notes: Make a sketch of the apparatus used to illustrate the antag- 
onistic action of muscles. SECTION III. FOODS AND DIGESTION 
( To illustrate Ritchie, Chapter VII} 
EXERCISE 25. MATTER AND ENERGY. PHYSICAL CHANGES. 
(class WORK) 
Experiment a. Water as solid, liquid, and gas. 
Apparatus and material: Evaporating dish or shallow 
tin pan; a piece of ice; thermometer; Bunsen burner. 
Procedure: Place a piece of ice in a shallow dish. Warm 
it and watch the ice liquefy (melt). Note the temperature 
throughout the experiment, stirring the water so that the 
average temperature of the liquid is recorded. How long 
does the liquid remain near freezing? Heat the water to 
boiling. Can you heat it higher than 212° Fahrenheit ( = ioo° 
Centigrade) ? Continue to boil the water until it has evapor- 
ated. Since the water remains cold until all the ice has 
melted and the water never goes over 212° F., though heat 
is continuously applied to it, it is seen that energy (heat) is 
absorbed (expended) when water passes from a solid to a 
liquid and from a liquid to a gaseous state. These changes 
are physical changes: water is water (H2O) whether as ice, 
as liquid water, or as water vapor. 
Notes : Write up the result of this experiment. 
Experiment b. Substances in solution. 
Apparatus and material: Water; a large vessel; a cup; 
a soluble dye, such as eosin. 
Procedure : In a quart of water dissolve a bit of eosin equal 
in amount to a grain of corn. The entire quart of water is 
colored. Pour a cupful of this solution into a quart of clear 
water and dilute a cupful of this second solution in the same 
manner. Continue the dilution until there is only a faint 
trace of color. In each successive dilution the particles of eosin 
39 40 
LABORATORY MANUAL 
are separated farther and farther apart, but each particle is still 
eosin. 
Notes: Define physical change and give examples. 
EXERCISE 26. CHEMICAL CHANGES. (DEMONSTRATION) 
Experiment a. Synthesis of water (synthesis = a putting 
together). 
Apparatus and material: The apparatus shown in Fig. 8, 
which shows a hydrogen generator and a means of collecting 
HYDROGEN GAS 
HYDROGEN GAS 
.DILUTE 
lHYLROCHLORIC ACID 
P- ZINC 
Fig. 8. Hydrogen generator. A, Erlenmeyer flask; C, shallow vessel of water; i 
thistle tube, to facilitate pouring the hydrochloric acid solution over the zinc; 2, deliv- 
ery tube; 3, candy-jar lid, which facilitates collecting of gas; 4, a notch in the lid for in- 
serting the delivery tube; 5, hole in lid; 6, test tube or bottle. The test tube is filled 
with water and inverted over the hole (5) in the lid. The gas bubbles up into the tube, 
displacing the water. 
gas under water; test tubes; a short glass tube drawn to a 
point; a short rubber tube for making a connection. (This 
apparatus requires some time to set up at first, but it may be 
cleaned and set aside for use year after year. In larger high 
schools the demonstration may be made to advantage in co- 
operation with the Department of Chemistry.) 
Procedure («): The preparation and collection of hydro- 
gen. Set up the apparatus for producing hydrogen as shown 
in Fig. 8 (unless a Kipp's generator is available). The hy- FOODS AND DIGESTION 
41 
drochloric acid should not be poured over the zinc until 
everything else is ready. The thistle tube facilitates the 
pouring of the acid into the flask. Gases may be collected 
under water in the following manner : The bottle or test tube 
to contain the gas is filled with water and inverted in a shal- 
low vessel also containing water. The delivery tube should 
end in the water of the shallow vessel. The gas is collected 
by allowing it to bubble into the inverted bottle. Take the 
tin lid of a candy jar and cut a circular hole about I inch in 
diameter in the center, and into the edge cut a notch about 
2 inch deep. Place the lid, round hole up, in the bottom of the 
vessel of water. Run the delivery tube through the notch 
of the lid so that the gas as it is expelled from the appa- 
ratus will bubble up through the hole in the center of the lid. 
The bottle to contain the gas is filled with water and inverted 
over the hole in the lid. Gas bubbling up out of the round 
hole of the tin lid will pass into the bottle, displacing the water. 
When everything is ready, add the acid to the zinc. Hy- 
drogen gas is generated at once. 
Caution : A mixture of hydrogen and oxygen is explosive, 
but pure hydrogen gas will burn with a steady flame. Allow 
the gas to bubble for ten minutes. Then test the gas as fol- 
lows : Collect a test tube of the gas. Hold the tube mantle 
down in a towel and place a lighted match at the mouth of 
the tube. If a slight explosion results, the hydrogen is not 
yet pure; if, on the contrary, the gas burns steadily on down 
the tube, the gas is pure and you may proceed with the next 
experiment. 
Procedure (b): The hydrogen flame and formation of 
water. When the gas coming from the generator is pure (as 
shown by its burning steadily and not exploding), attach to 
the delivery tube, by means of a rubber-tube connection, a 42 
LABORATORY MANUAL 
glass tube drawn out to a point. Apply a match to this point, 
and watch the gas burn. Hold a glass rod in the flame to 
test the heat. 
To show that water is formed when the gas burns, hold a 
cold dry piece of glass or a polished piece of metal to the 
flame and note the water condensed thereon. Water is 
formed (synthesized) by a union of the hydrogen of the gen- 
erator and oxygen from 
the air. The synthesis 
of water from hydrogen 
and oxygen involves a 
chemical change. 
Notes: Describe a 
method of producing water 
from hydrogen and oxygen. 
Experiment b. Anal- 
ysis of water (analysis 
= a tearing apart). 
Apparatus and ma- 
terial: The apparatus 
for the decomposition 
of water, shown in 
Fig. 9; a 10 % solution 
of sulfuric acid in water; 
three or more dry cells 
and several pieces of 
wire. 
Caution : In mixing 
strong sulfuric acid and 
water always pour the 
acid into the water, 
.STOP 
COCK 
HYDROGEN 
OXYGEN 
'PLATINUM 
CORK 
WIRE - 
Fig. 9. Apparatus for decomposition of water. 
The tubes are filled with 10 % sulfuric acid, the stop- 
cocks are closed, and a current of electricity is passed 
through the wires and the solution. Water is 
decomposed into hydrogen and oxygen in the pro- 
portion of two volumes of hydrogen to one volume 
of oxygen. FOODS AND DIGESTION 
43 
never the water into the acid. As heat is generated by the 
mixture, and as heat may break the glass container, pour 
the acid into the water a little at a time, allowing the solution 
to cool at intervals. 
Procedure: Set up the apparatus as shown. Fill the tubes 
with the dilute solution of sulfuric acid. Close the stopcocks 
at the top of the tubes. Connect the wires from the battery 
with the electrodes in the tubes. A current of electricity will 
pass through the solution and will cause the water to split 
into two parts of hydrogen and one of oxygen. As each will 
collect separately in one of the tubes, the quantity of each 
gas can be read off. 
Notes: Sketch the apparatus used in this experiment. Hydrogen 
and oxygen are elements ; water is a compound. Draw a diagram of 
an atom of hydrogen as in Ritchie, Fig. 44. Draw a diagram of an 
atom of oxygen. Draw a diagram of a molecule of hydrogen (compare 
with a molecule of iron, Ritchie, Fig. 43). Draw a diagram of a mole- 
cule of oxygen. Draw a diagram of a molecule of water. Can we 
speak of an atom of water? How many atoms in every molecule of 
an element? Of how many elements is water composed? How 
many atoms make up a molecule of water? 
Experiment c. Synthesis of sulfid of iron. 
Apparatus and material: A teaspoonful of iron filings; a like 
quantity of powdered sulfur; a test tube; a Bunsen burner. 
Procedure: Examine the iron and the sulfur. Note their 
color, weight, hardness, and other properties. Mix equal 
measures of iron filings and sulfur in a test tube and heat 
gradually until red hot. Allow the mass to cool. Break the 
test tube and examine the new compound, iron sulfid, the 
result of the union of iron and sulfur. 
Notes: Sketch a diagram of a molecule of iron (Ritchie, Fig. 43). 
Using a pentagon to represent an atom of sulfur, draw the diagram 44 
LABORATORY MANUAL 
of a molecule of sulfur. In a molecule of iron sulfid there are two 
atoms of iron and three of sulfur. Draw the diagram of a molecule of 
iron sulfid. 
Experiment d. Analysis of oxid of mercury. 
Material: A teaspoonful of oxid of mercury; a test tube; 
a Bunsen burner; a small splinter of wood. 
Procedure: Heat the oxid of mercury in a test tube over a 
flame. Oxygen is driven off from the compound. Heat the 
end of a splinter of wood until it glows. Thrust the glowing 
splinter into the test tube. The splinter bursts into flame, 
showing that oxygen is present in the tube. 
Notes: What is the source of oxygen in this experiment? Show 
how this illustrates chemical change. 
Experiment e. Synthesis of oxygen with other elements : 
(combustion). 
Apparatus and material: The apparatus shown in Fig. io 
(the potassium chlorate and the black oxid of manganese, from 
which the oxygen is to be generated, should be thoroughly 
mixed); a piece of picture wire; sulfur about the size of a 
grain of rice; a splinter of wood 5 or 6 inches long; three 
wide-mouthed bottles; three pieces of cardboard. 
LARGE 
TEST-TUBE, 
KC10 , 
AND 
MnO2 
OXYGEN- 
-BURNER 
^ATER 
Fig. io. Oxygen generator. The delivery tube and the apparatus for collecting gas 
are the same as in Fig. 8. Oxygen is driven off from the potassium chlorate and the 
black oxid of manganese by means of heat. FOODS AND DIGESTION 
45 
Procedure: When ready to collect oxygen, place the test 
tube over the flame. Oxygen will be driven through the 
delivery tube. Allow it to bubble into the water of the col- 
lecting pan until all the air originally in the test tube and the 
delivery tube has been driven out and replaced by relatively 
pure oxygen. The gas may then be collected over the hole 
in the candy-jar lid as directed for hydrogen. Fill the three 
wide-mouthed bottles or jars with the gas. Cover the mouths 
of the bottles with the pieces of cardboard and set them on 
the table ready for use in the following experiments : 
{a) Burning wood in pure oxygen. Heat a splinter of 
wood in a flame until it glows. Thrust the glowing splinter 
into one of the bottles of oxgen. What is the result? In 
combustion of wood, oxygen unites with the carbon in the 
wood, forming carbon dioxid (CO2) and with the oxygen, 
forming water (H2O). 
(/^) Burning a piece of iron picture-wire in oxygen. Wind 
the frazzled end of the picture wire about a small piece of 
sulfur and light the sulfur in a flame. Then quickly plunge 
the wire into a bottle of oxygen. The wire will burn with a 
white light. Note the end of the wire fused by the heat and 
the black oxid of iron covering the wire. 
Notes: Draw a diagram of a molecule of CO2 (Ritchie, Fig. 45). 
Iron oxid contains two atoms of iron and three of oxygen. Make a 
diagram of a molecule of iron oxid. Define oxidation. 
Review Exercise 1. All foods that can furnish the body 
heat and energy for work contain carbon. What happens to 
the food in the body when heat is produced? How can you 
show that organic foods contain carbon ? Discuss the subject 
further after studying Ritchie, pages 83, 84, 114, 115, 160, 
and especially pages 347 and 348. 46 
LABORATORY MANUAL 
EXERCISE 27. TESTING COMPOSITION OF FOODS. PROPORTION 
OF WATER IN FOODS. (CLASS WORK) 
Apparatus and material: Scales ; 15 to 20 g. each of 
potato, meat, and corn bread ; an evaporating dish. 
Procedure: Weigh small pieces of potato, meat, and corn 
bread. Evaporate them to dryness by slow heat; after which, 
weigh them again. 
Notes : Calculate the percentage of water in potato, meat, and corn 
bread. Compare your result with table, Ritchie, page 350. 
EXERCISE 28. COMPOSITION OF WATER. (CLASS WORK) 
Apparatus and material: A test tube; a teaspoonful of 
starch. 
Procedure: Dry the starch by slow heat. All free water 
should now have been removed. Place some of the dry starch 
in a test tube and heat it over a flame until the starch is 
charred. Note the water which condenses along the sides of 
the tube, especially near the mouth. The black substance in 
the bottom of the tube is carbon. 
Explanation : The water calculated in the preceding exercise 
(27) exists in the food as water and may be removed by 
evaporation. In this exercise, on the contrary, the water 
driven off by heat is water of composition, i.e. it is originally 
a part of the molecule of starch. In all carbohydrates, 
hydrogen and oxygen exist in the molecule in the proportion 
2:1, as in water (compare grape sugar, C6H12O6; cane sugar, 
C12H22On; starch, C6H10O5). In this experiment starch is 
broken up into carbon and water by heat. Study the follow- 
ing equation: n C6H10O6 = 6 C + 5 H2O. 
Notes: Describe the physical and the chemical changes involved 
in Exercises 27 and 28. FOODS AND DIGESTION 
47 
EXERCISE 29. IODINE TEST FOR STARCH. (CLASS WORK) 
Experiment a. Preparation of starch paste. 
Apparatus and material: A beaker or a tin cup ; 100 c.c. of 
water ; two teaspoonfuls of starch. 
Procedure: Boil a mixture of water and starch. A thin 
opalescent " solution " results. This will be referred to in the 
following exercises as starch paste. 
Experiment b. Effect of iodine on starch. 
Material: Test tubes; iodine solution; a glass rod or pipette; 
starch paste; potato; apple; and other substances to be tested. 
Procedure: To a quantity of starch paste in a test tube add 
a drop of iodine. If the color of the starch paste is very 
dark, dilute it with water until a bright blue color is seen. 
Add iodine solution to raw potato, cooked potato, bread, 
apple, cotton, sugar solution, or other substance which you 
desire to test. 
Notes: Write up this experiment according to the outline given on 
page 40. 
EXERCISE 30. TEST FOR GRAPE SUGAR, DEXTROSE, OR 
GLUCOSE. (CLASS WORK) 
Apparatus and material: Test tubes; Fehling's solution; 
a solution of grape sugar made by dissolving 10 g. of cheap 
stick candy in 100 c.c. of water; solution of cane sugar made 
by dissolving one teaspoonful of granulated sugar in 100 c.c. 
of water; a half cup of sweet milk; a test-tubeful of starch 
paste. (Label each solution carefully.) 
Procedure: Pour a small quantity of the grape sugar solu- 
tion into a test tube (to the depth of one half inch); add twice 
that quantity of Fehling's solution. Boil the mixture over a 48 
LABORATORY MANUAL 
flame (gently at first). The red color indicates that a " reduc- 
ing" sugar is present; in this case it is grape sugar. This 
test for sugar will be referred to below as Fehling's test. 
Try this test on a small quantity of sweet milk in the same 
manner. Sweet milk contains milk sugar, which is also a 
reducing sugar, as is proved by the red color produced in 
this experiment. We shall see below that malt sugar, found 
in the mouth after digestion of starch by saliva (Exercise 36), 
is also a reducing sugar. 
Try Fehling's test on a solution of cane sugar; on starch 
paste; no reduction (i.e. no red color) occurs. 
Notes: Write up these experiments.1 
EXERCISE 31. TESTS FOR PROTEINS. (CLASS WORK) 
Experiment a. Preparation of albumen solution. 
Apparatus and material: The white of an egg; 200 c.c. 
of water; an egg beater; a glass jar. 
Procedure : Beat up the white of an egg until it will " pour," 
and add it to 200 c.c. of water. This solution is a conven- 
ient form to use in demonstrating the reactions of protein. 
Experiment b. Orange color test for protein. 
Apparattis and material: Test tubes; albumen solution; 
strong nitric acid ; ammonia solution. 
Procedure : Add a few drops of nitric acid to a small quan- 
tity of albumen solution in a test tube; a white precipitate 
of protein results. Heat the mixture ; the precipitate be- 
comes yellow. Cool the test tube and add ammonia, a few 
drops at a time; the precipitate becomes orange, which in- 
1 All experiments should be written up according to instructions given in 
the chapter on How to use this Manual. FOODS AND DIGESTION 
49 
dicates the presence of protein. This test is called the xan- 
thoproteic test. 
Notes: Write up this experiment. 
Experiment c. Violet color test. 
Apparatus and material: Test tubes ; albumen solution ; a 
5 % solution of sodium hydroxid; a 10 % solution of copper 
sulfate. 
Procedure: To a quantity of the albumen'solution add io 
drops of sodium hydroxid solution. Shake the mixture. 
Add one drop of the copper sulfate solution and shake the 
mixture again; then add a second and a third drop in like 
manner. The violet color indicates protein. This test is 
called the biiirct test. 
Notes: Write up this experiment. 
Experiment d. Problem. 
Apparatus and material: Same as those in b, except the 
albumen solution; instead of this use a piece of finger nail. 
Procedure: Apply the xanthoproteic test (b, above) to the 
piece of finger nail. Is the finger nail composed of a sub- 
stance like protein ? 
Notes: Write up this experiment. 
EXERCISE 32. TESTS OF VARIOUS FOODS. (CLASS WORK) 
Experiment a. Wheat flour. 
Apparatus and material: Those needed in the test for 
starch (Exercise 29), for sugar (Exercise 30), for protein (Ex- 
ercise 31, b); two tablespoonfuls of wheat flour; a piece of 
cheesecloth about the size of a small handkerchief for each 
pupil; water. 50 
LABORATORY MANUAL 
Procedure: Moisten two tablespoonfuls of wheat flour so 
as to make a clough. Place an exact half of this aside for 
comparison later. Place the other half in a muslin or cheese- 
cloth sack (or use a rag brought together like a sack) and 
wash out of the flour all the starch possible, using many 
changes of wash water. At intervals test the wash water for 
classes of foods. After a time, gluten, a kind of protein, 
will be left in the rag. What are the characteristics of 
gluten ? Apply the xanthoproteic test to it. What is the 
result ? 
Notes: Write up this experiment, giving results in full. Estimate 
the proportion of gluten to starch in flour. Compare your results 
with those given for the solid portion of white bread. (See table, 
Ritchie, page 350.) 
Experiment b. Milk. 
Apparatus and material: Those needed for making the 
test for sugar and for protein ; a pint of sweet milk; a shallow 
vessel; microscope; slides and cover glasses. 
Procedure: (1) Test the sweet milk for sugar. (2) Allow 
a test-tubeful of milk to stand until the cream rises. To what 
class of foods does cream belong? (3) Mount a drop of 
milk on a slide, and observe it under the microscope. Note 
the numerous oil globules. (4) Pour some of the milk into 
a vessel and set it in a warm place until it sours or " clab- 
bers." Test the curd. What class of food is it composed 
of? Taste the whey; it is sour. The acid which makes it 
sour is lactic acid, which is produced from the milk sugar by 
bacteria. 
Notes: Write up these experiments. State why you think skim 
milk to be a wholesome, nutritious food. POODS AND DIGESTION 
51 
Experiment c. Testing various other foods for classes of 
foods. 
Material and procedure: Any food may be tested for sugar, 
starch, or protein, as desired: raisins, apples, potatoes, beans, 
bananas, etc. Find out whether good cane sugar or the 
cheaper grape sugar is used in certain cakes, bonbons, and 
the like. 
Notes: Make a record of the results of these tests. 
EXERCISE 33. PROCESSES OF DIGESTION. THE NEED OF 
DIGESTION. (CLASS WORK.) 
Experiment a. Soluble and insoluble defined. 
Apparatus and material: Three tumblers of water; half a 
teaspoonful of salt, of clean sand, and of starch; a sheet of 
filter paper ; a funnel. 
Procedure: Perform the experiment as directed (Ritchie, 
page 110). Instead of filtering the liquids as described, a 
funnel may be used to hold the filter paper. It will be found 
that a piece of filter paper folded as in Ritchie, Fig. 59, will 
fit perfectly into a funnel, whereas it does not fit into a tum- 
bler. Note from the figure how the folded paper is opened 
to fit the funnel: three thicknesses of the paper on one side 
and one thickness on the other. Vary the experiment by 
placing salt in one glass of water and starch in another. 
Set them aside for a day. Has the starch been dissolved ? 
Notes: Write up this experiment; define soluble and insoluble in 
your own words. 
Experiment b. Diffusion. 
Apparatus and material: A lump of potassium bichromate 
or copper sulfate ; a tall glass jar. 52 
LABORATORY MANUAL 
Procedure: Place a lump of potassium bichromate or 
copper sulfate in the bottom of a tall jar. Gently pour water 
into the jar. Set it aside in a quiet place. Note the diffusion 
of the salt into the liquid. Substances in solution diffuse from 
where they are abundant to where they are less abundant. 
Notes: Describe this experiment and apply the principle to 
Ritchie, Fig. 74. 
Experiment c. Diffusion through a membrane. (Demon- 
stration.) 
Apparatus and material: 100 c.c. of starch paste (see Ex- 
ercise 29, a); 100 c.c. of grape sugar solution (Exercise 30); 
two pieces of parchment tubing, 
each 8 inches long; a string; 
two quart jars of water. 
Procedttre: Soak two pieces 
of parchment tubing in water to 
soften them. Tie up one end of 
each tube. Fill one tube with 
the solution of grape sugar and 
the other with starch paste; 
then tie up the other ends of the 
tubes like a sausage, and hang 
the tubes in the jars of water. 
We may now call the tubes 
" sausage diffusion tubes " (Fig. 11). Set the jars aside for 
24 or 48 hours. At the end of either period test the water 
of one jar for sugar, the water of the other for starch. Has 
the sugar diffused through the tube into the surrounding 
water ? Has the starch diffused through ? 
Suggestion : The teacher may set up the experiment and 
have each pupil test the water in the jars for himself. 
PARCHMENT 
TUBE 
water; 
FIG. ii. Sausage diffusion tube. See 
Exercise 33, c. FOODS AND DIGESTION 
53 
Notes : Sketch the apparatus here used, and indicate the results 
in the drawing. What kind of substances only will pass through a 
membrane ? Study Ritchie, Fig. 60. The foods that pass into the 
cell and the wastes that pass out must pass through the membrane 
surrounding the cell. Study Ritchie, Fig. 76. Here it is seen that 
food absorbed by the blood from the intestine must pass through a 
membrane made up of cells. Apply the principle learned in the 
experiment described above to the absorption of food. State why 
food must be digested. Define digestion of food. 
Experiments d. Osmosis. 
Suggestion : The exercises given under this head may be 
assigned to different pupils, or may be demonstrated by the 
teacher. Experiments (4) or (5) may be substituted for (2). 
(1) Osmosis through the membrane of an egg. 
Apparatus and material: An egg; a glass or a beaker 
containing 5 % hydrochloric acid; a glass containing pure 
water. 
Procedure: Immerse the egg over night in dilute hydro- 
chloric acid solution to remove the shell. Then place the 
egg in water and allow it to stand for several days. Observe 
the increased size of the egg, which must now be handled 
with care. 
Explanation: The swelling of the egg is due to the fact 
that water has passed into it, thus putting the contents of the 
egg under pressure. The water diffuses into the egg because 
water is "less abundant" within the egg; that is, the solu- 
tion within is more dense than the " solution " without, there 
being nothing in solution in the water on the outside. This 
causes a flow of water inward through the membrane. This 
phenomenon is called osmosis. 
Notes : Write up this experiment. 54 
LABORATORY MANUAL 
(2) Further proof of diffusion of water into an egg. 
Apparatus and material: A jar and a bottle as shown in 
Fig. 12 ; an egg; a glass tube or straw ; sealing wax; a sup- 
port for glass tube. 
Procedure: Carefully pick the shell from the large end of 
an egg> taking care not to break the membrane under the 
shell, or the egg will be useless for the ex- 
periment. Drill a hole into the small end 
of the egg, and into this push a long straw 
or a glass tube about a foot long down to 
the yolk. If a glass tube is used, it must 
be supported. Wax the tubing in place so 
as to make the joint of egg and tube water- 
tight to prevent the contents of the egg 
from leaking out. Support the egg, large 
end down, in water, as shown in Fig. 12. 
Observe what follows. If the membrane of 
the egg is not broken, osmosis will take 
place, and the contents of the egg will rise 
in the tube. 
Notes: Explain this experiment. 
(3) Osmosis through the skin of prunes. 
(May be done at home.) 
Apparatus and material: A dozen dried prunes; a glass 
of water ; a glass containing enough sirup to cover six prunes. 
Procedure: Place six prunes in the glass of water and six 
in the sirup. Observe the changes that the prunes undergo 
in 24 hours. If desired, the experiment may be continued by 
removing the prunes from the water at the end of 24 hours 
and placing them in the sirup for a period of time. 
Fig. 12. Apparatus 
used to show diffusion 
through an egg mem- 
brane. (See Exercise 
33, d.) 7, jar of water; 
B, bottle; E, egg; T, 
glass tube; W, wax to 
seal the tube to the 
egg- 
Notes : In the light of the explanation given under the experiment FOODS AND D/GEST/ON 
55 
(i) above, explain the changes which the prunes undergo when sur- 
rounded by water and by sirup. 
(4) Osmosis through a carrot. 
Apparatus and material: A carrot; a brace and bit (|- or 
f-inch bit); a one-hole stopper to fit a |-inch hole; a glass 
tube to fit the hole in the stopper; sealing wax; a drop of 
red ink; strong sugar solution ; a vessel of water. 
Procedure: Cut off the leaves of a carrot, but do not injure 
the skin of the carrot. Bore a half-inch hole in the top or 
crown of the carrot, making the hollow as deep as possible. 
Do not break the skin of the carrot at any point. Fill the 
cavity with [the sugar solution, to which has been added a 
drop of red ink. Fit the glass tube in the hole in the stopper, 
insert the stopper, and seal the joint with sealing wax. 
Scrape the skin from the lower end of the carrot and stand it 
in water, supporting it if necessary. Observe what takes place. 
Notes : Explain this experiment. 
(5) Osmosis through a parchment tube or a "diffusion 
shell." 
Apparatus and material: A diffusion shell; a thistle tube ; 
a strong cord; a quart vessel of water; 10 % solution of 
molasses in water; support with clamps. 
Procedure: Fill the diffusion shell with the molasses solu- 
tion to overflowing. Force the large end of the thistle tube 
into the diffusion shell to such a distance that the molasses 
solution rises in the stem of the thistle tube. Make a water- 
tight joint between the diffusion shell and the tube by means 
of a stout cord. Set the shell in water and support it. It 
is essential for the success of the experiment that there be no 
leak between the diffusion shell and the thistle tube. 
Notes : Explain this experiment. 56 
LABORATORY MANUAL 
EXERCISE 34. MORE READY SOLUBILITY OF FINE PARTICLES. 
(class work) 
Experiment. Limestone changed chemically. 
Apparatus and material: A lump of salt; some finely 
powdered salt; a lump of limestone (or marble) ; two beakers 
of water; two beakers of 2 % hydrochloric acid. 
Procedure: (a) Place the lump of salt in one scalepan and 
in the other the same weight of powdered salt. Put the 
lump and the powder into beakers of water. Which dis- 
solves the more rapidly ? (^) Weigh out a lump of limestone 
and a quantity of powdered limestone in the same manner. 
Put each in a beaker of dilute hydrochloric acid. Which 
dissolves faster and why ? 
Notes: Apply the principle derived from these experiments to the 
advantages of chewing. (See also Exercise 43.) 
In the preceding experiment the limestone is changed 
chemically by the acid so that it is rendered soluble. 
EXERCISE 35. CHEMICAL DIGESTION. (CLASS WORK) 
Experiment a. Cane sugar changed chemically. 
Apparatus and material: Test tubes; a solution of a table- 
spoonful of sugar in 50 c.c. of water; 10% hydrochloric acid ; 
Fehling's solution. 
Procedure: Add 15 drops of the acid to 5 c.c. of the sugar 
solution in a test tube. Boil the mixture for 10 minutes. 
Make the test for grape sugar with Fehling's solution. Use 
enough of the Fehling's solution to make the mixture distinctly 
alkaline. The acid and the heat have changed the cane sugar; 
they have split the molecule of cane sugar to two of grape 
sugar as follows (see Ritchie, page 113): FOODS AND DIGESTION 
57 
^12^22^11 + H3O - c6h12o6 + c6h12o6 
Cane sugar + water = grape sugar 
Notes: Write up this experiment. 
Experiment b. Starch changed chemically. 
Apparatus and material: Test tube; starch paste; 10% 
hydrochloric acid; tin cup of water. 
Procedure: Add io drops of the acid to 5 c.c. of starch 
paste in a test tube and boil the mixture for 15 or 20 minutes. 
This is best done by setting the test tube in the cup of water, 
thus improvising a double boiler. Test the boiled mixture for 
sugar by Fehling's test. 
Notes: Write up this experiment. 
Explanation : Experiments a and b above merely illustrate 
chemical changes. The changes are brought about by heat 
and acid. The changes are, therefore, similar to but not 
identical with digestion or chemical changes of food in the 
body. Digestion in the body is not brought about by acid 
and high degree of heat, but by enzymes. (See Ritchie, page 
112.) Exercises 36 and 37 below show digestion by enzymes. 
EXERCISE 36. DIGESTION OF STARCH BY SALIVA. (CLASS 
WORK) 
Apparatus and material: Test tubes; a quantity of saliva 
collected in a bottle and filtered (see Exercise 33, a, for method 
of filtering); three test tubes containing starch paste ; a vessel 
containing a freezing mixture of cracked ice and salt; 
Fehling's solution. 
Suggestion : Several pupils may work together to advantage 
in each experiment. 
Procedure: (a) To test tube No. 1 of starch paste, add 
2-3 c.c. of saliva. Let a pupil hold the test tube in his hand 58 
LABORATORY MANUAL 
so as to keep it at body temperature, (b) Boil a test tubeful 
of saliva. To test tube No. 2 of starch paste add 2 c.c. of the 
boiled saliva. Hold this in the hand likewise to keep it 
warm, (f) Place a test tube containing saliva in the freezing 
mixture; also test tube No. 3 of starch paste. When both 
are cold, add 2 c.c. of cold saliva to the cold starch paste. 
Keep the mixture cold. 
After 15 minutes, test a sample from each test tube (Nos. 
1, 2, and 3) for sugar, using F'ehling's solution. Sugar is 
found only in which test tube ? 
Notes: Describe this experiment. What conditions are unfavor- 
able to digestion of starch by saliva ? (Digestion is due to enzymes ; 
in this case the enzyme is ptyalin of saliva. Heat destroys the enzyme 
and cold retards its action.) 
EXERCISE 37. THE DIGESTION OF PROTEIN BY GASTRIC JUICE. 
(class work) 
Apparatus and material: (1) Tubes of coagulated egg-white 
prepared as follows: place a num- 
ber of pieces of small glass tubing 
about three inches in length in a 
test tube and pour over them the 
beaten white of an egg (albumen) 
(Fig. 13, A). Be sure that the glass 
tubes become filled with the albu- 
men. Now set the test tube in a tin 
cup of water and bring this to a boil, 
thus coagulating (hardening) the 
albumen. Remove the glass tubes, 
now filled with solid albumen, from 
the test tube and clean them on 
the outer surface. Break them 
TEST TUBE 
GLASS TUBES, 
EGG-WHITE 
Fig. 13. A, apparatus needed to 
fill glass tubes with coagulated egg- 
white ; B, glass tubes filled with co- 
agulated egg-white and broken into 
three-fourths inch lengths. FOODS AND DIGESTION 
59 
into |-inch lengths (Fig. 13, B). The solid albumen should 
now fill the short tubes flush with the ends. Any digestion of 
the albumen in the experiment below can be readily detected. 
(2) Artificial gastric juice prepared by dissolving a teaspoon- 
ful of pepsin in 1000 c.c. of | % of hydrochloric acid. The 
weak acid solution is best made by adding 7^ c.c. of strong 
hydrochloric acid to 1000 c. c. of distilled water. 
Procedure: Place a tube of hardened albumen in a test 
tube and fill the test tube half full or more with artificial gas- 
tric juice. Set the test tube aside in a warm place, trying to 
keep it at about the temperature of the body (about ioo° F.). 
The digestion of the protein can be readily observed in the 
glass tubes. 
Notes: Write up this experiment. Compare with Exercise 36. SECTION IV. ANATOMY OF THE DIGESTIVE ORGANS 
EXERCISE 38. GENERAL VIEW OF THE VISCERA. (DEMON- 
STRATION) 
Experiment a. Preparation of the animal. 
Apparatus and material: Earthenware jar with lid, or air- 
tight box; chloroform; cat (or rabbit or rat); pins; dissect- 
ing board. 
Suggestion : In order to understand the structure of the 
organs it is necessary to see them in the body of an animal. 
It is best to use a mammal, such as a cat or a rabbit. The 
description here given applies particularly to a cat, but will 
suffice for the study of a rabbit or even a rat. It is not 
necessary to inject into the animal any fluid, such as formal- 
dehyde, fora study of the viscera, as the specimen need not be 
kept for more than a day or two. 
Procedure: Lay the animal, when killed, back down, on a 
dissecting board. Spread it out by tying the legs to the 
corners of the board. The animal is now ready for dissec- 
tion as described under b below. 
Notes: Describe how an animal may be humanely prepared for 
dissection. 
Experiment b. Dissection of the cat. 
Apparatus and material: The animal prepared as in a; 
dissecting instruments. 
Procedure: Make a longitudinal incision in the skin from 
the pubis to the lower jaw; then a circular incision around 
the abdomen. Separate the skin from the underlying parts 
and pin it back. Note the glistening connective tissue under 
the skin. Now open the body cavity, cutting through the 
muscular wall with a pair of scissors. Note the layers of 
muscles in the body wall. What are their functions? Con- 
tinue the incision forward through the sternum, using strong 
60 ANATOMY OF THE DIGESTIVE ORGANS 
61 
scissors or "bone forceps" to cut through the bone. Note 
the diaphragm, the muscular partition of the body cavity 
(Ritchie, Figs. 8-10). What is the name of the anterior part 
of the cavity? the posterior part? (Anterior means towards 
the head ; posterior, awacy from the head.) 
a. Organs of the thoracic cavity : 
The heart and the lungs are the conspicuous organs in the 
thoracic cavity. The heart is inclosed in a tough sac, the 
pericardium. If the specimen is a young animal, note 
the large pinkish thymus gland anterior to the heart and 
between the lungs. Note the smooth, moist covering of the 
lungs and a similar layer lining the thorax. Those two 
layers are the pleurae (Ritchie, Fig. 82). Make out the 
larger blood vessels leaving and entering the heart. Expose 
the trachea or windpipe. 
b. Organs of the abdominal cavity : 
Posterior to the diaphragm are chiefly the digestive, urinary, 
and reproductive organs. Find the esophagus where it 
pierces the diaphragm. Note where it enters the stomach. 
This is the cardiac (nearest the heart) end of the stomach. 
The large blind sac of the stomach on the left side is called 
the fundus. (The guide line to the word "stomach" in 
Ritchie, Fig. 46, touches the fundus of the stomach.) 
Where the stomach passes into the intestine there is a 
circular thickening, the pylorus (= gatekeeper), marked by a 
circular constriction on the outside (Ritchie, P'ig. 48). What 
is the function of the pylorus ? 
The small intestine is easily followed from the stomach 
through its various convolutions to the large intestine. If 
both a cat and a rabbit are available, compare the length of 
the herbivorous and the carnivorous intestine. Why is the 
small intestine so long that it must be coiled up ? 62 
LABORATORY MANUAL 
The large intestine receives the small intestine at right 
angles, leaving a blind sac, the caecum, to which, in many 
animals, is attached the vermiform appendix (Ritchie, Fig. 46). 
There is no appendix apparent in the cat. Define appendicitis. 
(The suffix -itis added to words means inflammation.) The 
large intestine consists of the ascending, transverse, and 
descending colons, and the rectum, which ends in the anus. 
The liver is a dark red body immediately posterior to the 
diaphragm. Note the lobes of the liver. Note how the liver 
fits up into the dome of the diaphragm and around the ad- 
jacent organs. Find the yellowish-green gall bladder. What 
is the function of this ? The pancreas is a pink-red body 
consisting of two parts, one lying dorsal to the stomach and 
the other in the first loop of the small intestine. Can you 
find where the gall bladder and the pancreas empty into the 
small intestine? The bile duct may be made visible by 
squeezing the gall bladder and forcing bile into the duct. 
(Compare Ritchie, Fig. 48; in the human body the two 
ducts usually empty into the small intestine by a common 
duct.) 
The spleen is a long, tongue-shaped, red-purple organ to 
the left of the stomach. The omentum is an apron-like 
structure covering the viscera. It is a part of the mesentery 
folds of connective tissue that support the organs. Spread 
out a portion of the intestines to show the mesentery. Note 
numerous knots of spongy tissue, the lymph nodes, in various 
parts of the mesentery. 
The urinary organs consist of the kidneys, ureter, and 
bladder. Find the kidney on each side, close to the dorsal 
wall. It is often surrounded by fat. Leading from the kid- 
ney to the bladder is a narrow white strand. This is the duct 
called the ureter. (See Ritchie, Fig. 90.) ANATOMY OF THE DIGESTIVE ORGANS 
63 
It has not escaped your notice that the organs are all 
smooth and moist. They are covered by a serous mem- 
brane, the peritoneum, which also lines the abdominal wall. 
(What is the meaning of the term peritonitis ?) A serous 
membrane is one which lines a closed cavity of the body. 
It is smooth and secretes a kind of serum or lymph. Its 
function is to prevent friction. The pleurae of the lungs, the 
pericardium of the heart, and the peritoneum of the abdomen 
are serous membranes. These can be pointed out at this time. 
Notes: Make the observations as directed above, and sketch the 
various organs as seen in the specimen or specimens. 
EXERCISE 39. INTERNAL STRUCTURE OF THE ORGANS. (DEM- 
ONSTRATION) 
Apparatus and material: Dissecting trays containing a 
little water; pieces of the esophagus and the small intestine 
about one inch long, taken from the specimen used in Exercise 
38; the stomach cut lengthwise into halves; dissecting in- 
struments and pins; a hand lens. 
Procedure: Slit the sections of the intestine and esophagus 
lengthwise. Pin these and the halves of the stomach on the 
bottom of the dissecting trays, under water. The pupils may 
now study the linings of the organs. Note the smooth lining 
of the esophagus and the folds, if any, of the other organs. 
With a hand lens examine the lining of the stomach to see 
if the fine pits, the openings of the gastric glands, are visible. 
(See Inner Surface of Stomach, Ritchie, Fig. 49.) Study 
the lining of the small intestine with care. Note the velvety 
appearance. (See Ritchie, Fig. 51.) Study the muscle layers 
of which the bulk of these organs is composed. Compare 
Ritchie, Figs. 49 and 51. 64 
LABORATORY MANUAL 
Notes : Describe the appearance of the inner lining of the esopha- 
gus, the stomach, and the intestine. Explain the velvety appearance 
of the inner surface of the intestine. Compare this with a coarse 
bath towel in appearance. 
EXERCISE 40. THE MOUTH, THE THROAT, AND THE SALIVARY 
GLANDS. (DEMONSTRATION) 
Experiment a. The salivary glands. 
Apparatus and material: The cat used in the preceding 
exercises; dissecting instruments. 
Procedure: Remove the skin from the head of the cat in 
the region of the ear. Salivary glands are seen below and 
behind the ear as pink, spongy masses just beneath the skin. 
Notes: Sketch a side view of the head, showing nose, mouth, ear, 
and salivary glands. 
Experiment b. Organs of the mouth and throat. 
Apparatus and material: Same as in the preceding experi- 
ment. 
Procedure: Cut away a little less than one half of the lower 
jaw of the cat, leaving the tongue in place. Dissect back, 
exposing the pharynx or the throat, laying bare the larynx or 
voice box. Pass a seeker, such as a knitting needle, into the 
esophagus, tracing it back into the stomach. A tonsil should 
be visible projecting out from the wall on the uninjured side 
just behind and below the root of the tongue. Find the 
tongue bone (hyoid) to which the tongue is attached. Note 
the posterior openings of the nasal passages. Press the soft 
palate forward, and with a broom straw or other seeker find a 
pair of slits in the upper wall of the throat. These are the 
openings of the Eustachian tubes leading to the middle ear. 
Leave the seekers in them so that they may be easily found ANATOMY OF THE DIGESTIVE ORGANS 
65 
by the pupil. Demonstrate the fact that the throat is the 
crossing place of the food and air passages (Ritchie, Fig. 83). 
Notes : Study Ritchie, Fig. 83, which represents a section through 
the head and neck of a man. Then draw a similar sketch showing a 
section through the head and neck of a cat. 
Experiment c. The human mouth. (Home work.) 
Apparatus and material: A hand mirror; one's own mouth. 
Procedure: With the aid of a mirror, study your own 
mouth: lips, gums, teeth, tongue, cheeks, hard palate, soft 
palate, uvula (tip of soft palate), throat, tonsils, glottis (open- 
ing into larynx), and epiglottis (covering of the glottis). (See 
Ritchie, Fig. 83, and The Human Body and its Enemies, 
Fig. 94.) 
Notes: Make a sketch of the open mouth. 
EXERCISE 41. THE TONGUE AND THE TEETH. (CLASS WORK) 
Experiment a. The tongue. 
Apparatus and material: Tongue of a cat; hand lens; 
tongues of other animals; mirror; pupil's own tongue. 
Procedure: (1) Study the tongue of the cat, using a hand 
lens if necessary. Make out the numerous tiny projections, 
called papillae, which give the surface a rough appearance. 
Cut out a piece of the tongue. Of what tissue is it chiefly 
composed? (2) Study your own tongue with the aid of a 
mirror. (3) Observe the tongue of a lizard, a toad, a snake 
(Ritchie, page 104). 
Notes: State the functions of the tongue; describe your own 
tongue. 
Experiment b. The human teeth. (Home work.) 
Apparatus and material: Hand mirror; one's own teeth. 66 
LABORATORY MANUAL 
Procedure: Study your own teeth with the aid of a mirror. 
Make out each kind according to Ritchie, Fig. 53. Note the 
two cusps or points on the bicuspids. 
Notes: Sketch one of each kind of human tooth. 
Experiment c. The teeth of other animals. 
Material: Skulls of various animals; a crayfish; the crop 
of a chicken. The enterprising boys of the class will be glad 
to add to the collection from specimens of dry, bleached 
skeletons found in the woods or prepared as directed in 
Exercise 10, b. 
Procedure: Study the teeth of rodents (such as squirrels, 
rats, etc.) with their prominent incisors; the teeth of her- 
bivorous animals (such as horse, cow, etc.); the teeth of 
carnivorous animals (cats and dogs); the teeth of insectiv- 
orous animals (the bat); the teeth of fish. 
An animal that has "teeth " in its " stomach " is the crayfish. 
Bring a live specimen to school, and keep it in an aquarium. 
Observe its manner of feeding. Kill a crayfish by chloro- 
forming it. Cut away the entire dorsal wall of the animal, 
using a pair of scissors to do this. The intestine is thus ex- 
posed. Note the large stomach in the anterior end of the 
body cavity. Slit this open with a pair of scissors, and find 
the three grinding teeth in the stomach. 
Bring to the laboratory the unopened crop of a chicken. 
Open the crop to show the pebbles it contains. How does 
the bird grind its food (not having teeth)? 
Notes: Record your observations as time permits. ANATOMY OF THE DIGESTIVE ORGANS 
67 
EXERCISE 42. FINER STRUCTURE OF THE DIGESTIVE ORGANS. 
(class work) 
Experiment a. The structure of a tooth. 
Apparatus and material: A human tooth (which may be 
obtained from a dentist's office); sealing wax; a block of 
wood; a file and a vise. 
Procedure: Imbed a tooth in sealing wax. To do this, melt 
the wax in a flame and let about ten drops fall on the block 
of wood. Lay the tooth upon this mass of wax. Then allow 
more molten wax to drip over the tooth until it is completely im- 
bedded. Place the block of wood in a vise, and file down tooth 
and wax to the pulp cavity of the tooth. The enamel, cement, 
dentine, and pulp cavity should now be plainly seen. Dis- 
tinguish the crown, neck, and root of the tooth (Ritchie, Fig. 52). 
Notes: Sketch a section of a tooth. 
Experiment b. Cross section of the esophagus. (Demonstra- 
tion.) 
Apparatus and material: Microscope and prepared cross 
section of the esophagus. 
Procedure: In the prepared section of the esophagus, make 
out with the microscope the mucous lining and the muscular 
walls. Note that the epithelium of the mucous membrane is 
several cells thick. The mucous membrane includes not only 
the epithelial layer, but also the underlying connective tissue 
layer. 
Notes: Make a drawing of the lining of the esophagus. 
Experiment c. Cross section of the stomach. (Demonstra- 
tion.) 
Apparatus and material: Microscope and prepared cross 
section of the stomach. 68 
LABORATORY MANUAL 
Procedure: The section of the stomach should show struc- 
tures represented in Ritchie, Fig. 49. Note especially (1) the 
epithelial tissue of the mucous membrane only one cell thick ; 
(2) the gastric glands, pockets of the mucous membrane dip- 
ping down into the wall of the stomach (study Ritchie, Figs. 
47, 49, and 50, By, (3) the muscular wall consisting of a 
thicker layer of ring muscles within and a thinner layer of 
longitudinal muscles without. 
Notes: Make a sketch of a portion of the wall of the stomach as 
seen. 
Experiment d. Cross section of the small intestine. (Class 
work.) 
Apparatus and material: Microscope and prepared cross 
section of the small intestine. 
Procedure: The section should show glands (intestinal 
glands) similar to those of the stomach and similar muscular 
layers. The most interesting structures of the intestine, not 
possessed by the other organs, are the villi (Ritchie, Fig. 51 ; 
see also Fig. 76). Note the one-celled epithelial layer of the 
mucous membrane. The blood capillaries of the villi may or 
may not be visible. 
Notes: Make a drawing representing several villi and intestinal 
glands of the intestine as seen under the microscope. 
Experiment e. Glands. (Home work.) 
Material: Ritchie, Figs. 47, 49, 50, 51, 54, 55, 76, 91, 93. 
Procedure: It is inadvisable in an elementary course to 
study glands further with a microscope, since the structure 
of the liver, a salivary gland, or the pancreas is too complex to 
be appreciated from the sections. The illustrations in Ritchie 
should be studied with care. Note that a gland consists of ANATOMY OF THE DIGESTIVE ORGANS 
69 
epithelial tissue arranged essentially as a pocket or a long tube. 
(Discuss Fig. 50.) This arrangement enables the gland to 
carry more secreting cells than it could if merely spread out 
like a pavement. Point out the secreting cells in Fig. 47. 
Note the blood vessels close to the cells. What does secrete 
mean ? Whence do the working cells receive their material ? 
Why are the blood vessels close to the cells ? Copy Fig. 47, 
labeling the secreting cells. Figure 49, B, is a more nearly 
exact representation of a gastric gland. Note that the intes- 
tinal glands of Fig. 51 resemble the gastric glands of Fig. 49. 
Wherein are the villi like the glands ? Wherein different ? 
Compare Figs. 47 and 76. Gastric and intestinal glands are 
simple glands. The pancreas and the salivary glands and 
the liver are compound, for they consist of many simple parts, 
united together. Study Fig. 54. What is the function of 
the ducts? Study Fig. 55. Note the duct. What parts of 
a salivary gland are like a simple gland ? (Compare Fig. 47 
and the individual parts of Fig. 55.) Compared and C of 
Fig. 93. It should now be clear that all these glands consist 
of epithelial (pavement) tissue arranged in the form) of Jtubes 
or tubular pockets. Draw a cross section of a gastric gland 
(Fig. 47) after Fig. 93, C. In the slide showing a cross section 
of the stomach, such cross sections as^just drawn may perhaps 
be found. 
How would a cross section through Fig. 49, A, along the 
line marked by the word Glands appear ? 
Notes: Answer the questions, and make the drawings as directed 
in the Procedure above. SECTION V. DIETETICS 
(To accompany Ritchie, Chapter X) 
EXERCISE 43. ADVANTAGES OF CHEWING. (CLASS WORK) 
Apparatus and material: Hard-boiled egg; cracker; Fehl- 
ing's solution ; test tubes ; hand lens. 
Procedure: (a) Chew a piece of hard-boiled white of egg 
for a short time; examine the lumps. Chew another piece 
for a long time; examine the fine particles of this mass with 
a hand lens, (b} Chew a cracker slightly; test the mass for 
sugar with Fehling's solution. Chew another portion until 
liquid; test this also for sugar. Which has the larger quan- 
tity of sugar as indicated by the color of the test ? 
Notes: Review Exercise 34. State the advantages of chewing 
food thoroughly. 
EXERCISE 44. STARCH GRAINS. (DEMONSTRATION) 
Apparatus and material: Microscope; slides and cover 
glasses; scalpel or other knife; raw potato; well-cooked potato. 
Procedure: Cut each potato in two. Scrape a knife blade 
across the cut surfaces, raw and cooked, and smear the scrap- 
ings on slides. Add a drop of water and place a cover glass 
over the preparations. Study them with the microscope. 
Note the starch grains and the cells. Ritchie, Fig. 61, shows 
the appearance of the raw potato. The starch grains are 
more conspicuous than the glass-like cell walls about them. 
In the cooked potato the starch grains are swollen and broken 
and can hardly be distinguished as starch grains. 
Notes: State the advantage of cooking vegetable foods. 
EXERCISE 45. INTESTINAL PARASITES. (DEMONSTRATION) 
Apparatus and material: Microscope ; prepared slide show- 
ing trichina encysted in muscle of pig ; specimens of tapeworm 
70 DIETETICS 
71 
and hookworm. A tapeworm may be secured from almost 
any physician; hookworms may be secured from physicians 
in many parts of the South. 
Procedure: Examine a section of pork muscle showing 
trichina (Ritchie, Fig. 62). Examine specimens of tapeworm 
(Fig. 63) and hookworm (Ritchie, page 354). Learn all you 
can about these parasites which live in the human intestine. 
Notes : Make a sketch of trichina found in pork. State why meat 
always be cooked. State how hookworm disease is spread and how 
it may be prevented. 
EXERCISE 46. CLEANLINESS OF FOODS. (CLASS WORK) 
Material: The dairies, restaurants, slaughterhouses, and 
grocery stores of your own town. 
Procedure: Study Ritchie, pages 327-332. Consult also 
Primer of Sanitation, Hartman and Bibb's The Human Body 
and its Enemies (World Book Co.), and other sources in order 
to learn what the sanitary conditions of your town ought to be. 
Make up a list of questions like the following, discuss the 
answers in class, and send committees on a tour of inspection 
where the answer is in doubt. Are the barns at the dairies 
clean ? Are the milch cows free from tuberculosis ? Is the 
milk drawn in wide open or narrowly open buckets ? Are 
the milk vessels thoroughly cleaned and scalded before being 
used ? Do any sick or convalescent persons handle the milk 
vessels at the dairy ? Are the slaughterhouses screened or do 
they swarm with flies? Are the floors of the slaughterhouses 
water-tight or does blood run through the cracks to decay 
under the floor ? Are the fruit stands screened ? Do the 
flies promenade over the candy and fruit at the grocery or 
confectionery store ? Does your town allow candies exposed 72 
LABORATORY MANUAL 
to the dust of the street to be sold ? Are the barns and horse 
lots behind the shops kept clean or are they breeding places 
for flies ? Does your baker, when on his round, handle alter- 
nately the harness of his horse and the bread you eat? Is 
the kitchen of the restaurant as clean as the dining room ? 
Does your water supply come from deep, safe wells or from 
shallow wells ? If it comes from surface streams, is it filtered 
before it is used ? 
Notes: Answer these and other similar questions; grade your 
town as to the sanitary conditions of its food supply on the basis of 
100 representing perfection. 
EXERCISE 47. ADULTERATION OF FOODS. (CLASS WORK) 
Material: The report of your State Pure Food Commis- 
sioner or Food and Drug Commissioner, to be obtained by 
the teacher for the school. 
Procedure and notes: Read the report and make a list of 
foods that are commonly adulterated. Make out and answer 
a list of questions similar to the following: How may milk 
be adulterated? How is it often preserved? How is the 
taste of decaying meat concealed ? What preservatives are 
used in meats ? How are vinegars adulterated ? What is the 
difference between a good and a poor grade of molasses, and 
how is the latter made to look like the former ? 
EXERCISE 48. PATENT MEDICINES. (CLASS WORK) 
Material: The report of the State Food and Drug Commis- 
sioner ; labels on patent medicine bottles from the drug store. 
(According to the Food and Drugs Act the labels must state 
the presence of certain drugs in the contents of the bottle.) DIETETICS 
73 
Procedure: Appoint a committee to go to the drug stores 
and look over the labels on the bottles of the patent medicines 
on sale. Make the following lists : 
(i) Medicines containing much alcohol. (Beer has 4-8 % ; 
wine, 15-20%; whisky, 30-50%.) 
(2) Medicines containing chloroform, laudanum, opium, 
morphine, codein, heroin, or other harmful drugs. 
(3) A list of baby medicines containing harmful drugs. 
(4) Find out what patent medicine labels give the term 
ethylic hydroxid for alcohol, trichlor methane for chloroform, 
and other misleading terms. 
(5) Find out what drugs are contained in most headache 
remedies. 
(6) Find out what soft drinks sold at soda fountains contain 
caffein. 
Notes: The notes should contain at least the first three lists 
mentioned above. SECTION VI. THE CIRCULATION 
EXERCISE 49. THE BLOOD. (DEMONSTRATION) 
Experiment a. Fresh human blood. 
Apparatus and material: Microscope; four slides with 
cover glasses; 1 % acetic acid solution ; a needle; a flame 
for sterilizing the needle (an alcohol lamp may be used). 
Procedure: Draw a drop of blood in the following manner : 
Wrap a handkerchief tightly around the left thumb; bend 
the thumb so as to put the blood under pressure in the thumb. 
With a needle sterilized in a flame, puncture the skin above 
the nail of the thumb by a quick stab. Collect one drop of 
blood on glass slide No. 1 and quickly cover with a cover 
glass. Collect another drop of blood in a drop of 1 % acetic 
acid on slide No. 2. Collect a third drop on slide No. 3 and 
cover this with slide No. 4. Separate slides Nos. 3 and 4 
after the drop of blood has spread, and lay them on the table 
to dry for use in the next exercise (b, below). 
Make out the red and the white blood corpuscles on slide 
No. 1-the red are of a yellowish tinge and are often ar- 
ranged in series like stacked saucers (lower left-hand corner, 
Ritchie, Fig. 72). Note shape of red corpuscles as seen from 
edge (middle of Fig. 72) and in flat view (top and bottom of 
Fig. 72). The white blood corpuscles are much less numer- 
ous and are almost transparent and white when unstained. 
Slide No. 2 will show white corpuscles only, the red ones 
having been dissolved by the acetic acid. 
Notes: Sketch the white and the red blood corpuscles as seen 
under the microscope. Represent the red corpuscles | inch in 
diameter and the white corpuscles in proportion. 
Experiment b. Stained blood. 
Material: Slides Nos. 3 and 4 set out to dry in a; cover 
glasses ; Wright's stain ; microscope ; a glass rod. 
74 THE CIRCULATION 
75 
Procedure: Place a drop of Wright's stain on the dry blood 
film of slide No. 3 and slide No. 4. Leave it on for five min- 
utes by the watch. Wash off the stain with distilled water. 
Wipe the lower surface of the slide dry, place a cover glass 
over the stained blood film (still wet), and study it under the 
microscope. Find white blood corpuscles with the nucleus 
stained blue as shown in Ritchie, Fig. 72. 
If it is desired to preserve the stained preparation perma- 
nently, the slide should be allowed to dry perfectly in the air 
after staining. A drop of liquid Canada balsam is placed in 
the middle of the film of stained blood and a well-cleaned 
cover glass placed on the balsam. The balsam will gradu- 
ally spread under the cover glass and bind the cover and 
slide together permanently. 
Caution : Care should be taken not to get any balsam on 
the lens of the microscope. Should this happen, it may be 
removed with a rag or tuft of cotton soaked in xylol or chloro- 
form. The balsam should be thin enough to spread readily 
under the cover glass. If too thick, add xylol. 
Notes: Sketch white blood corpuscles, stained. 
EXERCISE 50. THE CIRCULATION OF BLOOD IN A FROG OR 
A TADPOLE. (DEMONSTRATION) 
Experiment a. Tadpole. 
Apparatus and material: Microscope; a sheet of cork or 
thin board (a piece of shingle or a side of a cigar box), with a 
|-inch hole near one end; thread ; pins; a pithing needle; 
a tadpole or frog; glass^ slide; cotton; chloroform; dissect- 
ing intruments. 
Procedure: If a tadpole is used, lay it on a slide and 
cover the " head " with wet cotton so as to prevent the es- 76 
LABORATORY MANUAL 
cape of the animal. Lay a cover glass over the tail, support- 
ing it by small wads of paper or cotton so as to prevent 
crushing the tail. Fill vacant spaces around the tail under 
the cover glass with a drop of water. 
If a frog is used, pith the animal, brain and spinal cord. 
To do this, kill the animal with chloroform. Find the joint 
between the head and trunk of the frog on the dorsal sur- 
face by bending the head up and down. Cut through the 
skin at this point with a scalpel. Now insert the pithing 
needle or stiff wire and run it forward into the brain, twisting 
the needle so as to destroy the brain; then run it backward 
into the neural canal of the spinal column so as to destroy the 
spinal cord. The frog is now ready for study. The blood 
will continue to circulate for some time. 
Lay the animal on the board and spread the foot out over 
the hole, tying the toes apart with thread attached to pins. 
The web of the foot should be immediately over the hole in 
the board, and here the circulation may be observed through 
the microscope. 
Note arteries, veins, and capillaries. (Arteries have the 
blood flowing from the forkings of the blood vessels; veins 
toward these points.) Note the continuous flow of the blood. 
Note the white blood corpuscles often clinging to the walls 
of the vessels and the red corpuscles flowing on in the mid- 
dle of the stream. Note the size of capillaries in proportion 
to the size of corpuscles ; the relative length of capillaries 
and the relative number of red to white corpuscles. Com- 
pare Ritchie, Figs. 65 and 69; also Figs. 74 and 76. Find 
other figures in the text which show that capillaries function 
to connect arteries and veins. What is the principal function 
of the capillaries ? (See Fig. 74.) 
Notes: Describe the circulation of blood in the capillaries. THE CIRCULATION 
77 
EXERCISE 51. COLOR OF BLOOD. (CLASS WORK) 
Apparatus and material: A living mouse, rat, or frog; 
test tubes; narrow glass tube; chloroform ; dissecting in- 
struments. 
Procedure: Kill the animal which is to furnish the fresh 
blood. Remove the skin from the inner surface of the thigh 
and find an artery. Cut the artery and in a test tube collect 
the blood that flows from it. Note the color of the blood. 
With a straw or glass tube blow your breath (containing CO2) 
through the blood. Note the change of color in the blood. 
Notes: Describe and explain the differences in color between 
arterial and venous blood. 
EXERCISE 52. THE CLOTTING OF BLOOD. (CLASS WORK) 
Apparatus and material: An animal 'to furnish fresh 
blood ; chloroform ; dissecting instruments ; a 5 % solution of 
sodium oxalate ; ice ; three test tubes. 
Procedure ; Kill the animal by chloroforming it and expose 
an artery as in the preceding exercise. Have ready for 
receiving the blood three test tubes. Test tube No. 1 should 
be cooled on ice (e.g. in the freezing mixture as described in 
Exercise 36). In test tube No. 2 place 2 c.c. of a 5 % solu- 
tion of sodium oxalate. Test tube No. 3 is used without 
change. Collect 5-8 c.c. of blood in each test-tube. Place 
No. 1 on ice as soon as the blood has been collected in it. 
The cold will keep the blood from clotting. Clotting does 
not occur in test tube No. 2. Sodium oxalate among other 
chemicals prevents clotting. Compare with the way amo squito 
prevents the clotting of the blood of its victim. The blood 
in test tube No. 3 clots as follows: the blood, at first liquid, 
soon becomes a solid mass; the tube may be inverted without 78 
LABORATORY MANUAL 
spilling the blood. Later, the clot (fibrin) separates from 
the straw-colored serum. 
Notes: Describe the clotting of blood. How does the mosquito 
prevent the clotting of blood which he sucks from his victim ? 
Why does a mosquito bite cause itching ? How does a mosquito 
inject yellow fever or malarial germs into a person's blood ? 
EXERCISE 53. THE STRUCTURE OF THE HEART. (CLASS WORK) 
Material: Obtain from a butcher the heart of a calf or 
sheep. Have the butcher remove the heart from the animal 
in such a way that the pericardium (membranous sac in 
which the heart is encased) remains intact and the blood 
vessels attached to the heart are left as long as possible. 
Soak the heart in 1 % formaldehyde solution over night. 
Then preserve it in 5 % formaldehyde. If the class is large, 
several specimens should be secured. These may be pre- 
served from year to year. Other material needed are dis- 
secting instruments, including seekers (darning needles or 
thin rods of wood); pins; a piece of wood 2 by 3 inches; 
cotton. 
Procedure: (a) The principal blood vessels near the 
heart. Study Ritchie, Figs. 66 and 70, in connection with 
the heart before you. These illustrations represent the 
ventral view; the apex of the heart points to the left. 
Identify the left ventricle in the specimen; the apex is a 
part of the left ventricle. Lay the specimen on the dissect- 
ing board in a position to correspond to the figures in Ritchie. 
In this position almost the entire right ventricle is visible, 
only a portion of the other chambers being seen. Identify 
the right ventricle. Find the pulmonary artery. Find the 
right auricle and the vena cava ascending and the vena cava THE CIRCULATION 
79 
descending, both entering the right auricle. Run seekers 
into the venae cavae. The largest artery is the aorta; it 
orms an arch anterior to the heart. 
(£) The valves of the heart. Having identified the 
main divisions of the heart from without, slit open the right 
ventricle and the pulmonary artery, using a pair of scissors. 
Extend the incision into the wall of the auricle, opening this 
chamber also. Identify the tricuspid valves between the 
auricle and ventricle. The valves are flaps of connective 
tissue hanging down into the ventricles. Note the chordae 
tendinae (tendon-like cords) by which the margins of the 
valves are fastened to the wall of the ventricle. What is the 
function of the valves ? Study Ritchie, Fig. 64, to answer 
this question. To what in Fig. 67 do the chordae tendinae 
correspond ? 
Since the tricuspid valve prevents the blood from gushing 
into the auricle, which way must it flow? What'keeps the 
blood from flowing back into the ventricle when this relaxes? 
Find the semilunar valves of the pulmonary artery. Find 
the pockets as shown in Ritchie, Fig. 68. What name is 
applied to those valves in Ritchie, Fig. 64? 
Turn the heart around, dorsal side up. Open the left 
ventricle and the aorta. Note the bicuspid valve between 
auricle and ventricle with its chordae tendinae. Note the 
semilunar valves (Fig. 68) at the mouth of the aorta. Find 
pulmonary veins entering the left auricle. 
Pin labels to the specimens thus prepared, and let each 
pupil draw one side of the heart to show the structure. 
A dissection of the base of the aorta or the pulmonary 
artery, as represented in Ritchie, F'ig. 68, may well be mounted 
on a thin board and preserved for ready reference. Slit the 
artery at the base so as to bring the semilunar valves into 80 
LABORATORY MANUAL 
plain view, then cut out the base of the artery and pin it, or, 
better, tie it, well spread out, on a thin board of convenient 
size. A little cotton stuffed into the pocket-like valves will 
make them stand out more plainly. Preserve the preparation 
in 80% alcohol or 5% formalin. 
Notes: Make a drawing of the right side of the heart, cut open 
lengthwise. 
EXERCISE 54. TRACING THE COURSE OF THE BLOOD. (HOME 
work) 
Material: Ritchie, Figs. 66 and 70; notes on the dissection 
of the heart. 
Procedure and notes: After studying the heart, it should be 
easy with the aid of Ritchie, Figs. 66 and 70, and page 144 
of the text to trace the course of the blood throughout the 
body. The teacher may now assign several problems, such 
as the following: Trace the blood from the left side of the 
heart through the head back to the left side; trace the blood 
from the right lung to the left lung; trace the blood from the 
right auricle to the left auricle; trace the blood through the 
liver by two partly different routes. 
EXERCISE 55. THE BEATING OF THE HEART. 
(demonstra-tion) 
Apparatus and material: Frog; chloroform; pithing 
needle ; Ringer's solution ; shallow vessel. 
Procedure: Pith a frog as described in Exercise 50. 
Open the chest cavity. Immerse the frog in warm Ringer's 
solution. Observe the beating of the heart. Where does 
each beat begin (wave of contraction is indicated by paleness 
of part)? 
Notes: Describe the beating of the frog's heart. THE CIRCULATION 
81 
EXERCISE 56. THE LYMPH VESSELS OF THE INTESTINE. 
(demonstration) 
Apparatus and material: Rat or young cat; chloroform ; 
dissecting instruments. 
Procedure: Feed a rat or a young cat with milk, cheese, 
or fat meat. Kill it with chloroform one hour after feeding. 
Open the abdominal cavity at once, and observe the white 
streams of lymph containing fat in the lacteals and lymph 
vessels which are found in the mesentery of the intestine. 
See Ritchie, Figs. 66 and 76; in these figures the lymph 
vessels are represented in black. 
exercise 57. demonstrating the valves in the veins, 
(home work) 
Material: One's own hand. 
Procedure: (See Ritchie, page 159.) Allow your hand to 
hang down, and press the forearm against the edge of the 
table. This makes the veins of the wrist or back of the hand 
stand out boldly. Press on a vein with one finger. On the 
side of the finger toward the heart, empty the vein by rubbing 
another finger along it. Does the blood flow back into the 
vein ? On the other side of the finger that is pressing the 
vein, rub the blood away from the heart. Does the blood 
flow back into the vein ? Explain. Now remove the first 
finger. Rub a vein downward toward the fingers. Can you 
find the place of a valve in the vein ? 
EXERCISE 58. THE HUMAN PULSE AND HEARTBEAT. (HOME 
work) 
Apparatus and material: A watch ; for (£) a handkerchief 
and a small, strong stick. 
Procedure : (a) The pulse. The pulse is usually felt in the 82 
LABORATORY MANUAL 
radial artery on the thumb side of the wrist. The tips of the 
fingers should be used in feeling the pulse. Find the pulse 
also on the temple, in front of the ear, and under the knee. 
(b) Bleeding. Study Figs. 135 and 136 and note where the 
arteries come close to the surface. Practice the application 
of the tourniquet as shown in Fig. 136, taking for granted 
that the artery of the wrist has been cut. 
(c) Pulse rate. Count your pulse rate per minute after lying 
still for ten minutes; after sitting; after standing; after 
walking ; after running or hopping. After the last count, sit 
down and find out how long it takes for the pulse rate to go 
back to the normal rate for the sitting posture. Why must 
the heart beat faster when we exercise ? (Get the answer 
from Ritchie, Figs. 60, 74, and 81.) 
(^Z) Heartbeat. Feel the heart "beat" between the fifth 
and sixth ribs a little to the left of the sternum. Apply the 
ear closely to this point in another person, and hear the two 
sounds of the heart. These are probably due to the closing 
of the bicuspid and tricuspid valves (causing the first sound) 
and the semilunar valves (causing the second sound). 
Notes: Write up each of the experiments in this exercise, record- 
ing your results in full. 
EXERCISE 59. WHY THE BLOOD FLOWS IN A STEADY 
STREAM IN THE CAPILLARIES. (DEMONSTRATION) 
Experiment a. Elastic arteries are required for a steady 
stream. 
Apparatus: Prepare the apparatus pictured in Fig. 14. 
This consists of glass tubing, soft elastic tubing, a large 
aspirator bulb, and a tumbler of water. The glass tip of 
A and B is made by drawing out a glass tube to a point THE CIRCULATION 
83 
as fine as desired. To do this, heat the glass tube in the 
flame of a Bunsen burner. If gas is not available, the teacher 
may use a gasoline blow torch such as is used by plumbers. 
Heat the tube until it can be drawn out easily. To represent 
the left ventricle of the heart, an aspirator bulb of large size 
will do. This has a valve at each end; one might represent 
the bicuspid valve, the other the semilunar valve. Arrange 
the bulb so that when it is squeezed in the hand in imitation 
of the heartbeat ( = contraction of the ventricle) the water 
CAPILLARY TIP 
VALVE 
.VALVE, 
CAPILLARY TIP 
GLASS TUBE 
TUBE WIDE OPEN 
RUBBER TUBE 
RUBBER TUBE 
Fig. 14. Apparatus to illustrate experiments in Exercise 59. One aspirator bulb may 
be used in the three positions (A, B, and C). Water is pumped out of the tumbler into 
the tubes A, B, and C by squeezing the bulb with the hand. A steady stream flows 
from B only, which has a tube with flexible walls and a capillary tip. 
( = blood) is sucked up out of the tumbler (see A of Fig. 14) 
through the bulb and into the tube. What does this tube 
represent ? The fine point of the tip of A and B represents 
the capillaries. 
Procedure : Place the bulb in connection with the glass 
tube as in A. Squeeze the bulb at regular intervals, say 
about once a second. The stream issuing from the tip 
always comes in jerks. Place the bulb as in B. Squeeze 
the bulb as before. At first the spray issues from the tip 
in spurts; but after the pressure is sufficient to distend the 
rubber tube (= artery) a steady stream issues. Feel the 84 
LABORATORY MANUAL 
"pulse." These experiments show two things: (i) that 
there must be sufficient pressure to distend the arteries. (In 
case of great loss of blood, a normal salt solution is usually 
injected into the arteries to make up the volume of the blood.) 
(2) That the arteries must be elastic. 
Experiment b. The resistance offered by the capillaries is 
essential for a steady stream. 
Apparatus: Same as in a. 
Procedure : Remove the capillary tube from B and replace 
it with an open tube as in C. Pump the water with the bulb. 
No steady stream is obtainable because the pressure cannot 
accumulate when there is no resistance at the outlet. 
Experiment c. More energy is required to pump water into 
a tube with rigid walls than into an elastic tube. 
Apparatus: Same as in a. 
Procedure: Pump water first into the glass tube A and 
then into the rubber tube B, feeling the difference in the 
force required to pump water in the two positions. (See 
Ritchie, top of page 156.) 
TUBE 
GLASS TUBE 
RUBBER TUBE 
FIG. 15 Apparatus for Exercise 59, d. The rubber tube delivers more water 
than the rigid tube. THE CIRCULATION 
85 
Experiment d. An elastic tube with elastic walls delivers 
more water than a similar tube with rigid walls. 
Apparatus : As shown in Fig. 15, the two arms of the Y-tube 
are of the same size. 
Procedure; With the aspirator bulb, pump water simul- 
taneously into the glass tube and the rubber tube through 
the Y-tube. Measure the water delivered by the two tubes. 
Notes: Write up the experiments performed in this exercise. SECTION VII. RESPIRATION 
EXERCISE 60. THE LUNGS AND THE AIR PASSAGES. 
(demonstration) 
Experiment a. The lungs. 
Apparatus and material; A cat; chloroform; a killing jar 
or box; dissecting instruments; two pieces of glass tubing, 
each four inches long and a rubber tube to connect them; 
dissecting board. 
Procedure; Kill the cat by chloroforming it. Stretch it 
out on a dissecting board, back down. Dissect the organs 
of respiration according to the following directions : 
Remove the skin from the ventral surface of the body, and 
open the thoracic cavity as directed in Exercise 38. Cut 
away the muscles of the neck so as to expose the larynx, or 
voice box, and the trachea, or windpipe. These are readily 
recognized on account of the stiff rings of cartilage in their 
walls. Trace the air passages, beginning at the nose. Cut 
off the cartilaginous tip of the nose to see the irregular nasal 
passages. The posterior opening of the nasal passages into 
the throat have been noted previously (Exercise 40, b). Trace 
the trachea to its division into the two bronchi, which pass into 
the lungs. Now, to inflate the lungs, insert one of the short 
glass tubes into the trachea. Attach to this the other glass 
tube by means of the rubber connection in such a way that 
the rubber may be pinched together after the inflation of the 
lungs. Inflate the lungs by blowing through the glass tube. 
Caution : When the lungs are inflated, the air in them is 
under pressure; if, therefore, the pressure from the breath is 
relieved, the air in the lungs is likely to rush out and blow 
mucus into the mouth of the experimenter. This can easily 
be avoided by pinching together the rubber connection before 
relieving the pressure. 
86 RESPIRATION 
87 
Note the color of the lungs. Cut off a portion of one lobe 
of the lungs ; air bubbles emerge from the cut bronchial tubes 
and air sacs. Place the portion cut off in water; it floats. 
Why? 
Notes: Make a sketch of the lungs and the air passages. 
Experiment b. The trachea, bronchi, and bronchial tubes. 
Apparatus and material: The dissection made in a; 
microscope; a prepared slide of the trachea. 
Procedure: Follow a bronchus into one of the lungs and 
dissect the lungs along one of the larger bronchial tubes as 
far as practicable. Study Ritchie, Fig. 84. Note in the 
dissection that the larynx is a box of cartilage. Open it and 
find the vocal cords. Compare with Ritchie, Figs. 85 and 86. 
Note that the wall of the trachea and the bronchi (the two 
main branches of the trachea) are supported by rings or 
" hoops " of cartilage. Are the hoops complete rings ? 
This can best be determined by a study of a cross section of 
the trachea with the microscope. In this section note also 
the lining of the trachea, which consists of epithelial cells 
like those pictured in Ritchie, Fig. 6. The cilia will probably 
be visible on these cells, but with difficulty. 
Notes: Sketch a cross section of the trachea as it appears under 
the microscope. 
EXERCISE 61. LUNG CAPACITY. (CLASS WORK) 
Apparatus: A spirometer. This instrument is commonly 
used in gymnasiums for measuring lung capacity. If this is 
not available, use the apparatus shown in Fig. 16. It con- 
sists of a large bottle having a capacity of one gallon (231 
cubic inches, or 4500 c.c.), which is large enough for the use 88 
LABORATORY MANUAL 
of high school pupils; a large shallow pan capable of hold- 
ing about two gallons of water; a rubber tube; bent glass 
tube through which to blow air into the bottle; a vessel of 
disinfectant. 
Procedure: If a spirometer is available, proceed at once 
with its use. If the bottle is to be used, fill it full of water 
and invert it in the pan containing a small quantity of water. 
Leave a space under the mouth 
of the bottle to receive the end 
of the tube. The bottle may be 
tilted and held by one pupil while 
a classmate makes the test. The 
end of the tube should be disin- 
fected and washed each time 
before it is taken into the mouth 
of another pupil. 
When ready, the experimenter 
takes the deepest inspiration pos- 
sible. Then, placing one end of 
the tube in his mouth, he forces 
the greatest quantity of air out of his lungs into the bottle, 
thus forcing out the water from the bottle and replacing it 
with air from the lungs. The volume of air in the bottle 
may easily be measured. If it fills the gallon bottle % full, 
the capacity of the lungs is fof 231 cubic inches, or 173 
cubic inches. 
To facilitate the reading off of the volume of air in the 
bottle, a paper strip may be pasted on the outside of the 
bottle as shown in Fig. 17. On this strip of paper a scale 
is marked as follows: Set the bottle in an upright position 
and pour water into it 100 c.c. at a time. On the strip of 
paper mark the level of the water after each addition and 
Fig. 16. Bottle used as a spirom- 
eter. The bottle is filled with water 
and inverted without loss of contents 
into a vessel of water. The volume 
of water displaced by blowing into 
the bottle measures the lung capacity. RESPIRATION 
89 
number the marks representing 
ioo's (up to 45oo+ c.c.). You 
now have a scale that can easily 
be read off. To prevent the 
paper from coming off when wet, 
paint over it a film of shellac 
(io g. of shellac dissolved in 
50 c.c. of alcohol). 
The normal lung capacity for a 
young man 5 ft. 8 in. in height is 
225 cu. in., or 3700 c.c. For each 
inch of stature less than this the ca- 
pacity is 8 cu. in., or 125 c.c., less. 
Notes : Make a record of your lung 
capacity; calculate what the normal or 
average lung capacity is for a person 
of your height. Make a table of these 
two items for all the pupils of the 
class and note whether the average of 
the class is above or below the normal. 
EXERCISE. 62. THE SWEEPING ACTION OF THE CILIA. 
(demonstration) 
Apparatus and material: A frog; a killing box; chloro- 
form ; dissecting instruments; Ringer's solution. 
Procedure: Kill a frog with chloroform. Cut off the 
head, and from this remove the lower jaw. Lay the cranium 
down, with the palate up, and keep the roof of the mouth 
moistened with Ringer's solution. Place a very small flake 
of cork or blotting paper on the posterior edge of the 
mucous membrane of the mouth (i.e. nearest the throat) 
Fig. 17. A scale pasted on the out- 
side of the bottle facilitates reading 
off the volume of air in the bottle. 
See Exercise 62 for method of mak- 
ing the scale. 90 
LABORATORY MANUAL 
and observe that the cork is " swept " forward toward 
the lips. 
Notes: Explain how the flake of cork is swept forward on the 
mucous membrane of the mouth in this experiment. (See Ritchie, 
Figs. 3 and 6.) 
EXERCISE 63. CHEST EXPANSION. (HOME WORK) 
Experiment a. Measuring the chest expansion. (Class 
work.) 
Apparatus ; A tape measure. 
Procedure; Measure your chest with a tape measure along 
the line of greatest expansion (9th rib): (1) after greatest 
possible inhalation; (2) after greatest possible exhalation. 
The difference is the "chest expansion." 
Notes: Make a record of your measurements in this exercise. 
Experiment b. Exercise to increase the chest expansion. 
Apparatus: A tape measure. 
Procedure: By taking proper breathing movements daily 
it is possible to increase one's chest expansion considerably. 
Each morning on rising and each night before retiring, a 
number of deep breaths should be taken, aided by the proper 
movement of chest, shoulders, and arms. The exercises 
should be taken out of doors or at an open window. It is a 
good plan, moreover, to perform the exercises in the class- 
room between recitations, with the windows thrown open. 
The following suggestions will prove helpful: 
In taking the breathing exercises stand firmly with the 
weight on the balls of the feet, heels together, toes turned 
out at a comfortable angle, head up, shoulders and hips back. 
Inhale deeply, at the same time rolling the shoulders back RESPIRATION 
91 
as far as possible and turning the palms of the hands outwards. 
Raise the elbows to the level of the shoulders, bend the arms 
at the elbow until the finger tips touch in front of the chest. 
Throw the arms outwards horizontally, bend back the head and 
the trunk, and take a long, deep breath. Bring the arms, head, 
and trunk back to the starting position and exhale forcibly. 
Vary the exercise by starting with the hands at the sides. 
Take a deep breath while gradually raising the arms sidewise 
to a horizontal position; lower the arms more rapidly and 
exhale forcibly. 
Notes: Measure your chest expansion every two weeks while 
practicing these exercises, and keep a record of the increase of 
expansion. 
EXERCISE 64. HOW WE BREATHE. (DEMONSTRATION) 
Experiment a. Raising and lowering the ribs (chest ex- 
pansion). 
Apparatus and material: Ritchie, Figs. 16, 19, and 32. 
Procedure: In Figs. 16 and 19, note that the ribs hang 
down in front, i.e. are lower at the ventral end than at the 
dorsal. This can be seen in side view of the orangutan, 
Ritchie, Fig. 32. When one set of muscles between the ribs 
contracts and raises the ribs and the sternum, the diameter of 
the chest between the backbone and the sternum (and there- 
fore the capacity of the chest) is increased. When the ribs 
are depressed, the air is forced out of the lungs because the 
capacity of the chest is decreased. 
Notes: Using Ritchie, Figs. 16, 19, and 32, draw a side view of 
three ribs with the vertebrae and the sternum to which they are 
attached. Sketch them first lowered in expiration ; then with dotted 
lines represent them raised in inspiration. 92 
LABORATORY MANUAL 
Experiment b. Lowering the diaphragm (abdominal 
breathing). 
Apparatus: The model shown in Fig. 18. If a bell jar 
with a hole at the top is not available, cut the bottom off a 
large bottle. This can be done in the following manner: 
Scratch the bottle with a hard file along the line where it 
is desired to break it. Soak a string in kerosene oil, and 
wrap it around the bottle over the 
scratch. Burn the string, and, while 
the bottle is still hot, immerse it in 
cold water. The bottom should fall 
off smoothly. Remove any cutting 
edge from the bottle with a file. The 
rubber balloon is such as is sold 
on whistles (or " squawkers ") at cir- 
cuses. The tube connecting with the 
balloon is passed through a rubber 
cork which fits tightly into the mouth 
of the bottle. A collar button or a 
marble is tied in a piece of sheet rub- 
ber (which may be purchased from 
a dentist) for a handle. The rub- 
ber is tightly fastened to the bottom 
of the bottle or bell jar with strong 
cord. The " handle " should occupy a position in the cen- 
ter as shown. All joints should be air tight. This appa- 
ratus, except the sheet rubber and the balloon, may be 
kept from year to year; these latter deteriorate and soon 
lose their elasticity. 
Procedure: The chest wall, the lungs, the air passages, and 
the diaphragm of the body are represented in the model by 
the bottle, the rubber balloon, the tube, and the sheet rubber 
AIR-TIGHT 
JOINT 
BELL JAR 
SHEET 
/RUBBER 
BUTTON TIED 
INTO RUBBER 
FOR HANDLE 
Fig. 18. Model to show the 
action of the diaphragm in 
breathing. (See Exercise 63, 
b.) RESPIRATION 
93 
respectively. Pull the rubber " diaphragm " by the handle, 
and observe the inflation of the lungs. 
Notes: Describe this experiment, and show how it illustrates the 
process by which air gets into the lungs in breathing. 
EXERCISE 65. ARTIFICIAL RESPIRATION. (CLASS WORK) 
Apparatus and material: Ritchie, pages 274-276, and Figs. 
132-134; also the Red Cross abridged textbook on First 
Aid to the Injured. One of the boys in the class should serve 
as the subject upon whom the method is demonstrated. 
Procedure: Follow the directions given in Ritchie for 
removing water from the lungs, supposing breathing to have 
ceased on account of drowning and not from suffocation by 
natural gas, lightning, or other accident. Place at the head 
of the subject a hot-water bottle or heated stone wrapped in 
a coat. Warming the head of the patient is said to prevent 
convulsions. Practice one method in which one operator works 
and one method in which two work. The methods represented 
by Ritchie, Figs. 133, B, and 134, are probably the best. 
With one operator at work the pressure is applied to the 
lowest ribs and is directed forwards as well as downwards. 
Where two operators are at work as in Fig. 134, one presses 
against the lower end of the sternum and the arch of the ribs 
(see Ritchie, Fig. 19), at the same time the other presses the 
arms of the patient against the chest. Both operators remove 
the pressure suddenly and at the same time. The arms of 
the patient are swung around horizontally during inspiration. 
The two movements should be repeated in unison about 
fifteen times per minute. 
Notes: Write out the methods of artificial respiration as observed ; 
state also other useful treatment of the patient. 94 
LABORATORY MANUAL 
EXERCISE 66. NUMBER OF BREATHING MOVEMENTS. (HOME 
work) 
Procedure: Count the number of breathing movements per 
minute in different persons, as indicated by the movements of 
the chest. Do this without the knowledge of the subject 
under observation. Count the number of breaths taken by a 
person after he has been running, as well as after a period of 
rest. 
Notes: Record the results of your observations and explain them. 
EXERCISE 67. ANALYSIS OF AIR. (CLASS WORK) 
Experiment a. Air needed to support combustion. 
Apparatus aud material: Those represented in Ritchie, 
Fig- 79- 
Procedure: Perform the experiment as directed, page 161. 
Notes: Describe the experiment and explain what happens. 
Experiment b. Carbon dioxid will not support combustion. 
Apparatus and material: The apparatus shown in Fig. 19 
(compare with P"ig. 8); pieces of limestone and marble; 
10% hydrochloric acid; a jar with a burning candle. 
Procedure: The apparatus shown in Fig. 19 is known as a 
carbon dioxid generator. The gas is driven off the limestone 
by the acid. Carbon dioxid need not be collected under 
water as in the case of hydrogen for, being much heavier than 
air, it will flow into a jar like water. The gas may be 
gathered by simply letting it flow out of the delivery tube 
into a jar^or tumbler. 
Have ready a tumbler to receive the gas and place a lighted 
candle in a jar at a distance from the generator. Pour the RESPIRATION 
95 
acid over the limestone, and allow the gas to flow for about 
ten minutes. Then collect a tumblerful of the gas, and pour 
DILUTE 
HYDROCHLORIC 
ACID 
LIGHTED 
CANDLE IN 
TUMBLER 
-LIMESTONE 
FIG. 19. Carbon dioxid generator. (Compare with Fig. 8.) As"carbon dioxid is a 
heavy gas it may be gathered in a tumbler and poured into another vessel as water is 
poured. 
it over the burning candle. The candle is extinguished at 
once. 
Notes : Describe the properties of carbon dioxid. 
Experiment c. Air always contains a trace of C02. 
Apparatus and material: A glass of limewater (fresh lime 
dissolved in water); a glass tube bent at one end; an aspira- 
tor bulb. 
Procedure: Filter the limewater so as to get it perfectly 
clear. Pump air through the glass of limewater with the 
aspirator bulb. After a time the limewater will become 
cloudy, indicating absorption of CO2 from the air. 
Notes: Write up this experiment, sketching the apparatus used. 96 
LABORATORY MANUAL 
Experiment d. Oxygen makes up about one fifth of the air ; 
nitrogen four fifths. 
Apparatus and material: The apparatus shown in Fig. 20. 
The match is set upright in a flat cork 
and floated in a shallow pan. 
Procedure: Light the floating match 
and at once invert the jar over the 
burning match head. The phosphorus 
of the match head will burn out the 
oxygen from the jar. The water will 
rise to replace the oxygen. Measure 
the distance the water has risen. 
Remove the jar and set it upright. 
Test the remaining gas (nitrogen) in 
the jar by lowering a burning match 
into it. Nitrogen will not support 
combustion. 
Notes: Write up this experiment. 
EXERCISE 68. CHANGES IN EXPIRED AIR. (CLASS WORK) 
Apparatus and material: A tumbler of limewater ; glass 
tubes ; thermometer ; large jar. 
Procedure: To show that expired air contains more CO2 
than inspired air blow the breath through a tumbler of lime 
water. Compare the result with that obtained in Exer- 
cise 67, c. 
To show that expired air is warmer than the surrounding 
atmosphere, blow upon the bulb of a thermometer. 
To show that expired air contains considerable moisture, 
blow upon a window pane or other plate of glass and note 
the moisture condensed on the glass. 
F'lG. 20. Apparatus for burn- 
ing oxygen out of the air in a 
jar with a match head. M, 
match; J, quart jar; D, dish 
of water; A, level of water 
after removal of oxygen by the 
burning of the match head. RESPIRATION 
97 
To show that expired air contains organic matter, blow the 
breath repeatedly into a quart jar that has previously been 
thoroughly cleaned. Seal the jar and set it in a warm place. 
Three weeks later smell the contents of the jar. Organic 
matter from the breath has decomposed. 
Notes: Write up each experiment in this exercise. 
EXERCISE 69. RESPIRATION IN OTHER ANIMALS. (CLASS 
WORK) 
Apparatus and material: Earthworms in a shallow dish 
containing a very little water; an insect such as a grass- 
hopper or a white beetle grub; a goldfish in a glass aquarium; 
a frog or toad. Beetle grubs such as are found in well-rotted 
logs are very desirable for study. The toad should be kept 
in a box containing moist earth covered over with leaves. 
Procedure: Study the animals mentioned above with a view 
to observing how they get their supply of oxygen. An 
earthworm has neither gills nor lungs, but " breathes " 
through the skin. Note the blood vessels, which can be seen 
through the moist, thin skin. 
An insect has fewer blood vessels than an earthworm, but 
it has air tubes which carry the air directly to all parts of the 
body. The openings to these air tubes may be seen along 
the sides of a grasshopper and more plainly along the sides 
of white beetle grubs. 
Observe the fish and the toad. Note how each gets a 
supply of oxygen (Ritchie, page 169). 
Notes: Write up your observations on respiration in these animals. SECTION VIII. VENTILATION 
EXERCISE 70. HEATED AIR RISES. (CLASS WORK) 
Apparatus and material: A shoe box with two holes cut in 
it as shown in Fig. 21; a candle; several 
small rags that have been soaked in saltpeter 
solution and allowed to dry. 
Procedure: Place a lighted candle in the 
shoe box. Demonstrate the " ventilation " of 
the shoe box brought about by the burning 
candle. This may be done best by creating 
a smoke and noting the direction of the air 
currents. A good cloud of smoke is produced 
by a smoldering rag which has previously 
been soaked in saltpeter. 
Perform the experiment described in 
Ritchie, page 181. The room should be well 
warmed when the experiment is tried, and 
the wind should not be blowing strongly 
from the direction of the open doorway. 
Notes : Write up the experiments in this exercise. 
EXERCISE /I. SYSTEMS OF HEATING AND VENTILATION. 
(home work) 
Material: The heating and ventilating systems of schools 
and other public buildings of the community. 
Procedure: Study the method by which your school build- 
ing is heated and ventilated. If the rooms are heated by 
stoves, are there fresh-air inlets under them and are the 
stoves supplied with a jacket ? Is there a foul-air outlet in 
connection with the smoke flue? Is there a pan of water on 
the stove to prevent extreme dryness of the air ? Is there an 
Fig. 21. To show 
that heated air rises. 
Two holes are cut 
in a shoe box; a 
lighted candle fur- 
nishes heat. The 
current of air is 
made visible by 
means of smoke. 
98 VENTILATION 
99 
automatic regulator on the stove? If the building is heated 
by a furnace, are the rooms supplied with foul-air outlets ? 
Is the air moistened artificially after it passes the furnace ? 
Is there a thermometer on the wall of your schoolroom ? Is 
there also a hygrometer ? 
Study the means of ventilation of your moving-picture 
shows and theaters. Are there electric fans in use to force 
the foul air out and draw the fresh air in ? Is the room kept 
clean or does the dust fly thickly about when people move 
about in the room ? 
Notes : Make a record of your observations. 
EXERCISE 72. SANITARY LAWS PERTAINING TO VENTILATION. 
(home work) 
Material: A copy of the Sanitary Code of your state and 
the sanitary ordinances of your city. The former may be 
obtained from the State Health Officer and the latter from 
the proper city authority. 
Procedure: Study the Sanitary Laws with regard to venti- 
lation of schools, playhouses, depots, sleeping cars, and the 
like. Are the laws obeyed in your city or town ? 
Notes : Make a list of important sanitary laws that are fairly well 
obeyed, and a list of those that are entirely neglected. 
EXERCISE 73. OPEN-AIR LIVING. (CLASS WORK) 
Procedure and notes: Make a study of the screened sleep- 
ing porches of your neighborhood and write an essay on the 
advantages of the screened sleeping porch. SECTION IX. THE KIDNEYS 
EXERCISE 74. THE STRUCTURE OF THE KIDNEY. (CLASS 
work) 
Apparatus and material: The kidney of a sheep or ox, 
obtained from a butcher; a scalpel. 
Procedure: Review Exercise 38, b, in which the position of 
the kidney, ureter, and bladder was pointed out. (See Ritchie, 
Fig. 90.) Cut a kidney in half lengthwise through its 
greatest diameter (as shown in Ritchie, Fig. 91, A). The 
cut surface will show the cortex (near the surface) and 
the pyramids, as well as the hollow or pelvis, from which 
the ureter springs. A good preparation should also show 
the renal vein and the renal artery. (See Ritchie, Fig. 90.) 
Which of these two blood vessels carries the " purer " blood 
and why ? 
Notes: Make a drawing of a longitudinal section of a kidney. 
EXERCISE 75. THE MICROSCOPIC STUDY OF THE KIDNEY. 
(demonstration) 
Apparatiis and material: Microscope; a prepared slide of 
an injected kidney. 
Procedure: Study the section under the microscope. The 
section should show the renal corpuscles in the color of the 
injection used. If the animal was injected with blue, the 
renal corpuscles will appear as blue spots, because a renal cor- 
puscle is a mass of blood capillaries (Fig. 90) surrounded by 
epithelial tissue. The " pocket " thus formed communicates 
with a tubule (Fig. 91, which carries off the secretion 
(excretion) into the pelvis. (See the upper right-hand corner 
of the section represented in Fig. 91, A.) The five pyramids 
shown in Fig. 91, A, are bundles of tubules; one of the 
tubules is shown very much enlarged, with its pocket or 
100 THE KIDNEYS 
101 
"corpuscle," in Fig. 91, B . Every corpuscle with its tubule 
is comparable to a sweat gland (Fig. 93). Compare Fig. 91, C, 
and Fig. 93, B. 
Notes: Describe the finer structure of the kidney according to 
Ritchie, Fig. 91, and state how the parts look under the microscope. SECTION X. THE SKIN AND THE BODY TEMPERATURE 
EXERCISE 76. A STUDY OF RITCHIE, FIGS. 93-96. (HOME 
WORK) 
Material: A copy of Ritchie's Human Physiology. 
Procedure: Study first the plans of the drawings shown in 
Figs. 49 and 51. They represent blocks of tissue which are 
shown in three dimensions like a cube. Note that the 
" inner surface of the stomach," Fig. 49, A, showing mouths 
of gastric glands, corresponds to Fig. 95, which shows 
mouths of sweat glands. Figure 51 likewise corresponds 
to the sweat pores of Fig. 95. Note that Fig. 94 is the 
upper portion of Fig. 93, the epidermis, more enlarged. 
Figure 96 shows a hair, which reaches down into the dermis 
as far as the fatty layer. Note blood vessel at the root of 
the hair. 
Notes : After having made out all the structures in the skin shown 
in Figs. 93-96, make a single drawing of a "block" of skin about 
nine times the size (in area) of Fig. 93, embodying all the features 
of Figs. 93-96. The drawing should be in three dimensions after the 
manner of Figs. 49 or 51. Figure 93, A, widened out, would furnish 
two sides, Fig. 95 the upper surface-of the block. The cells should 
be drawn somewhat as in Fig. 94. The hair shown in Fig. 96 could 
be placed in the section beside the sweat gland of Fig. 93, A. (See 
The Human Body and Its Enemies, Fig. 161.) 
EXERCISE 77. SECTION OF THE SCALP. (DEMONSTRATION) 
Apparatus and material: Microscope; a prepared slide of 
the human scalp. 
Procedure: A good slide of the human scalp, studied under 
the microscope, should show the features pictured above. It 
is well to have several slides for demonstration under differ- 
ent microscopes at the same time, as one showing a hair, an- 
102 THE SKIN AND THE BODY TEMPERATURE 
103 
other the cut coil of a sweat gland (as seen in Fig. 93, C), a 
third a pore, etc. 
Notes: Sketch a section of the scalp as seen under the microscope. 
EXERCISE 78. THE GROWTH OF THE FINGER NAIL. (HOME 
work) 
Apparatus and material: A knife. 
Procedure: Cut a small notch in a finger nail near the 
lunula (= little moon, from the half-moon-shaped light area at 
the base of the nail). 
Notes: Keep a weekly record of the movements of the notch. 
State the manner in which the nail grows forward from the root. 
EXERCISE 79. HEAT REGULATION OF THE BODY. (CLASS 
WORK) 
Experiment a. Source and distribution of heat. 
Procedure: Review Exercise 26, e (2). Review Ritchie, 
pages 114, 115, 347, and 348. 
Exercise the right arm in a warm room. Does the work- 
ing arm only become warm or is the warmth felt all over the 
body ? 
Notes : State the source of heat in the body. Why do we become 
warmer when we exercise ? Discuss the function of the blood as 
the distributor of heat in the body. 
Experiment b. Loss of heat from the body. 
Apparatus and material; An incandescent electric light, 
burning; a lump of beeswax or paraffin; an iron bar, six 
inches long; a stewpan of water; two thermometers; alco- 
hol ; chloroform. 104 
LABORATORY MANUAL 
Procedure: The following experiments show how heat is 
lost by radiation, conduction, and convection and through 
evaporation. 
a. Radiation. Touch a burning incandescent light globe. 
Heat reaches your hand. The heat passes from the glowing 
filament to the glass side by radia- 
tion, there being no gas within the 
globe. 
b. Conduction. In the preced- 
ing experiment the heat passes 
through the glass of the globe by 
conduction. Place some beeswax 
or paraffin on the end of the iron bar. 
Heat the opposite end in a flame. 
Soon the wax will melt. Explain. 
Dry air is a poor conductor of 
heat. Therefore, ice boxes are 
built with air spaces between 
double walls. Woolen or fur 
clothing is warmer than cotton or 
linen because it imprisons most air 
in its meshes. 
c. Convection. Boil a little 
water in a tall vessel. Note that 
the hot water at the bottom rises 
to the top. The heat causes con- 
vection currents in the water. 
Review Exercise 70. The candle 
causes convection currents in the 
box. Why do we blow on a hot object to cool it? Objects 
cool faster by convection. Why is a rubber coat or " slicker " 
most effective against cold winds ? 
Fig. 22. To show the effect of 
evaporation on temperature. A, 
thermometer with bulb in water: 
little evaporation. B, thermometer 
with wet rag tied over bulb. The 
rag is fanned to hasten evaporation. THE SKIN AND THE BODY TEMPERATURE 
105 
d. Evaporation, (d) Tie a dry handkerchief about one 
hand and a wet one about the other. Wave the hands in 
the air. Which feels the cooler? (z^) Take two thermome- 
ters. Place one in a vessel of water. Wet a rag with the 
same water and tie it about the bulb of the other, as shown 
in Fig. 22. Fan the thermometers so as to hasten evapora- 
tion. Read the temperatures. Which records the lower 
temperature ? (r) The more volatile a liquid the more quickly 
does it cool on evaporation. Pour alcohol, ether, or chloro- 
form on the hand and allow it to evaporate. What is the 
result ? 
Notes: Describe each of the four ways by which the body loses 
heat. Discuss fully the function of sweat. SECTION XI. THE NERVOUS SYSTEM 
EXERCISE 80. DISSECTION OF THE NERVOUS SYSTEM. 
(demonstration) 
Apparatus and material: (i) The dissection of a cat's 
brain used in Exercise 8. If carefully prepared, this is a 
valuable specimen for demonstration. It can be kept in- 
definitely in a tall, clear glass jar. It should show the cen- 
tral nervous system on the dorsal side and the sympathetic 
system on the ventral side. (2) The brain of a sheep for 
detailed study. Have the butcher remove the brain under 
your personal direction. The skull should be clamped in a 
vise and sawn in two with a circular cut. The cut should 
be made in a horizontal line corresponding to a boy's hat- 
band. The roof of the skull can thus easily be removed. 
The brain should then be carefully removed together with 
the dura mater, or tough outer covering. It is well to have 
ready to hand for purposes of demonstration one entire 
brain with the nerves attached and several others sectioned 
in various planes. Soak the brains over night in 1 % formal- 
dehyde and then preserve them in 5 % formaldehyde. 
Procedure: The brain, spinal cord, and sympathetic 
system should be studied in greater detail than was done in 
Exercise 8. 
a. The brain. Distinguish the cerebral hemispheres, the 
cerebellum, and the medulla. In man the cerebrum is so 
large as to cover the cerebellum entirely, so that the latter is 
invisible from above (Ritchie, Fig. 100). In the lower ani- 
mals the cerebellum projects beyond the posterior border of 
the cerebrum. The medulla appears like an anterior en- 
largement of the spinal cord. Note the pons (= bridge), a 
band of fibers extending around the medulla and connecting 
the two halves of the cerebellum. Press the two halves of 
the cerebrum apart and note the broad white band of fibers 
106 THE NERVOUS SYSTEM 
107 
(the corpus callosum} which connects the two halves of the 
cerebrum. Point this out in Ritchie, Fig. 99. 
Cut the brain along the median plane into two exact 
halves. Viewing the cut surface of the left half, you now 
see the parts represented in Fig. 99. None of the gray 
matter of the cerebrum has been cut through; the cerebel- 
lum has been sectioned through both the white and the gray 
matter. Observe the arbor vita (a section of the cerebel- 
lum), so called from the shape of the white matter {arbor 
vita = tree of life(. Note that the gray matter is on the 
outside and the white matter on the inside. Make a horizon- 
tal section of the cerebrum a little lower than the word 
" cerebrum " in Fig. 99. The relation of gray and white 
matter can easily be seen. Note the convolutions of the 
brain. The gray matter is seen to follow the convolutions. 
b. The spinal cord and the sympathetic system. (Demon- 
stration.) The dissection of the spinal cord as directed in 
Exercise 8 should show the spinal nerves given off, a pair 
between every two successive vertebrae. The spaces through 
which the spinal nerves emerge can be seen in Ritchie, 
Fig. 21, or in any vertebrate skeleton. In the dissection, the 
processes of the vertebrae and the bony arches covering the 
spinal cord should be pinched off with a pair of bone forceps 
piece by piece. Care should be taken not to destroy the 
cord or the nerves. Note that each spinal nerve has a 
ganglion. The ganglia can be seen as knots of tissue (in 
the cat about the size of a pinhead) just outside the dura 
mater of the cord. Careful observation will show that each 
nerve is made up of two roots and that the ganglion is a part 
of the dorsal root. (See Ritchie, Fig. 103.) 
Notes: Describe the central nervous system, making the appro- 
priate drawings. 108 
LABORATORY MANUAL 
EXERCISE 81. REFLEX ACTION IN THE FROG. 
(demonstration) 
Apparatus and -material: A frog or toad; chloroform; 
a killing box; a pithing needle; 10% acetic acid. 
Procedure: Pith the brain only of the frog. (See Exercise 
50.) Lay the animal on the table. Stretch out the leg. Is 
it withdrawn ? Apply a drop of 10% acetic acid to the hind 
foot; to the chest; to the side. What is the result in each 
case ? 
Now destroy the spinal cord also by pithing it. Repeat 
the experiments performed before pithing the cord. Does 
response to stimulus (reflex action) take place ? Why not ? 
Notes: Study Ritchie, Figs. 101 and 104, and write out a com- 
plete answer to the question asked above. 
EXERCISE 82. REFLEX ACTION IN PUPIL'S BODY. (HOME WORK) 
Apparatus and material: Hot water ; a bristle ; a mirror. 
Procedure : a. Make a person wink by striking at him. 
b. Count your pulse. Now breathe thirty times a minute 
for three minutes and count the pulse again. 
c. Sterilize a bristle in hot water. Let a friend close his 
eyes. Insert the bristle as far as possible into the nasal 
cavity. What is the result ? It has been suggested that the 
purpose of this reflex is to prevent insects from entering the 
nostrils of sleeping persons. 
d. Sterilize a bristle. Have the subject open his mouth 
and sing " Ah ! " Touch the throat with the bristle. What 
is the result? Why does a person sneeze in one case and 
cough in the other ? 
e. Hold a mirror before you. Note the size of the pupil 
of the eye. Close the eyes one minute. Open them sud- THE NERVOUS SYSTEM 
109 
denly and at the same instant notice the size of the pupil. It 
is larger, but grows smaller at once. 
Notes: Give the results obtained in each experiment of this exer- 
cise. Define reflex action. 
EXERCISE 83. REACTION TIME. (CLASS WORK) 
Apparatus and material: A stop watch. 
Procedure: Let ten or more pupils and the teacher join 
hands and form a circle. The teacher should have a stop 
watch clasped between his right hand and the left hand of 
the pupil on his right. The teacher then gives the signal by 
pressing the hand of the pupil to the right and at the same 
time starts the watch. The first pupil passes the signal on 
to the pupil at his right by a pressure of the hand and so on 
around the circle. When the signal reaches the teacher, he 
stops the watch. The total time required for the signal to 
travel around the circle divided by the number of persons in 
the experiment gives the average reaction time for each. 
Perform the experiment a second time, reversing the 
direction. 
Notes: Describe the course the nerve impulse travels from the 
pupil's left hand to his right hand in this experiment. SECTION XII. THE SPECIAL SENSES 
EXERCISE 84. TOUCH. (HOME WORK) 
Experiment a. The temperature sense. 
Apparatus and material: Two blunt wires. 
Procedure: Perform the experiment described in Ritchie, 
page 248. Determine the warm and the cold spots on a 
square inch of skin on the lower surface of the wrist. Use 
warm and cold blunt wires. Mark the warm spots with 
black ink and the cold spots with red ink. 
Notes: Make a diagram on paper of the warm and the cold spots 
as determined in this experiment. 
Experiment b. Delicacy of touch. 
Apparatus and material: The apparatus shown in Ritchie, 
Fig. 115; a bristle fastened to a handle. A straw from 
a whisk broom may be clamped between the rubber of a lead 
pencil and the metal sheath, the pencil serving as the handle. 
Procedure: (1) Perform the experiment described in Ritchie, 
page 248. (2) Let the subject close his eyes. Touch differ- 
ent parts of his body with the bristle and determine in which 
the least pressure of the bristle may be felt. 
Noles : Write up these experiments. 
EXERCISE 85. DISTINGUISHING BETWEEN TASTE AND SMELL. 
(class work) 
Material: Tufts of cotton; slices of potato, apple, onion, 
and a piece of apple slightly flavored with vanilla. 
Procedure: Let the subject stop his nostrils tightly with cot- 
ton, open his mouth, and close his eyes. Place on his tongue 
in succession the slices of potato, apple, and onion, and the piece 
of apple flavored with vanilla. Can he distinguish the objects ? 
Why do not foods " taste " when a person has a cold ? 
Notes : Discuss the results of this experiment. 
110 THE SPECIAL SENSES 
111 
EXERCISE 86. DISSECTION OF THE EAR. (DEMONSTRATION) 
Apparatus and material: The head of a cat; 10% hydro- 
chloric acid; dissecting instilments. 
Procedure: With the aid of Ritchie, Fig. 119, distinguish 
the parts of the human ear. It is quite possible to demon- 
strate all these by dissection of the ear of a cat. 
Note the external auditory canal in the ear of the cat. 
Cut this away and dissect down to the bottom of the canal, 
where the tympanic membrane may be seen. Note the 
" handle " of the hammer attached to the ear drum. 
Now cut away the skin and flesh from the skull and soak 
it in 10 % hydrochloric acid for 48 hours. At the end of 
that period it will be possible to cut the bone. Open the 
middle ear, exposing the ear bones (see Ritchie, Fig. 130). 
The stirrup is found touching the oval opening (" opening 
for stapes," Fig. 121). By careful dissection it is possible to 
expose the cochlea and the semicircular canals. Cut away 
a little of the bone at a time. If the operation is successful, 
the specimen may be kept in alcohol or formaldehyde. 
Notes: Copy Ritchie, Fig. 119. 
EXERCISE 87. TESTS FOR HEARING. (CLASS WORK) 
Apparatus: A large dollar watch. 
Procedure: Choose a quiet room to make the tests. Make 
all tests under the same conditions. Blindfold the pupil to 
be tested and let him stop one ear with a finger (cover the 
finger with a clean cloth). Hold the watch at such a distance 
that the ticking cannot be heard and gradually bring it nearer 
to the pupil. Ask him to give a sign as soon as he can hear 
the ticking. Measure the distance at which the ticking is 
first audible. 112 
LABORATORY MANUAL 
Test the other ear in the same way. 
Test all the pupils and find the average distance at which 
the watch is heard. Seat those having the dullest sense of 
hearing nearest the teacher's desk. 
Notes: Describe the test for hearing here given and make a record 
of several cases tested. 
EXERCISE 88. DISSECTION OF THE EYE. (CLASS WORK) 
Experiment a. External features of the human eye. 
(Home work.) 
Apparatus: A mirror. 
Procedure; With the aid of a mirror study your own eye 
and the means of its protection. Observe that it is set back 
in the orbit of the skull. Note eyebrows, eyelids, eyelashes, 
iris, "white" of the eye. Note that the eyeball is covered 
and the eyelid lined with a smooth membrane, the conjunc- 
tiva. The conjunctiva is continually moistened with tears or 
lachrymal fluid from glands of the same name. The tear is 
removed through the tear duct. (Study Ritchie, Fig. 122.) 
Find the opening of the tear duct at the summit of a small 
papilla on the lower eyelid near the inner corner of the 
eye. 
Notes: Sketch the external features of the human eye as observed 
in the mirror. 
Experiment b. Eye of ox or cat. 
Apparatus and material: Eyes of oxen ; the head of a cat 
dissecting instruments. 
Procedure: Dissect out the eye of a cat or secure the larger 
eye of an ox. If the cat's eye is dissected, note the muscles 
that move the eyeball and the large white optic nerve (cf. THE SPECIAL SENSES 
113 
Ritchie, Fig. 123). Remove the eyeball. (Study Ritchie 
Fig. 124.) Note from the figure that the transparent cornea 
is continuous with the sclerotic coat and the iris with the 
choroid coat. The lens is encased in a capsule and is held 
in place by a ligament attached to radiating ciliary processes. 
Cut two broad slits, one on each side of the eyeball, so as to 
verify these points in the specimens. 
Cut another eyeball in vertical section at right angles to 
the section shown in Fig. 124. That is, separate the eyeball 
into anterior or front half and posterior or back half. The 
latter would contain the nerve, the former the pupil and 
lens. Lay the halves down cut side up. In the posterior 
half the retina covers the entire interior of the eyeball except 
one spot, the blind spot. This marks the point where the 
optic nerve leaves the eyeball. Another spot, the yellow 
spot containing the area of keenest vision, is marked by a 
notch in Ritchie, Fig. 124. 
In the anterior half of the eyeball, study the lens and its 
manner of suspension by a ligament. Cut the capsule of the 
lens and remove the lens from it. 
Notes : Make a sketch of each half of the eyeball as seen from the 
inside. 
EXERCISE 89. ACCOMMODATION. (.HOME WORK.) 
Experiment a. Accommodation necessary. 
Procedure: Hold a finger before the eye in line with a dis- 
tant object, say a tree. Close the other eye. Focus the at- 
tention upon the tree : the finger is out of focus, i.e. the image 
of the finger is blurred. Focus on the finger: the image of 
the tree is blurred. 
Notes: Write up this experiment. 114 
LABORATORY MANUAL 
Experiment b. Muscular effort needed for close vision. 
Procedure: Repeat experiment a and note carefully that 
muscular effort is required to pass from far to near vision. 
The muscles that contract are the ciliary muscles. The lens 
bulges out by its own elasticity (dotted line, Ritchie, Fig. 129), 
but the muscles serve to pull the attachment of the suspensory 
ligament forward so as to give the lens " slack." 
Notes: Write up this experiment. Copy Ritchie, Fig. 129, draw- 
ing in red the muscles which contract in accommodating the eye for 
close vision. 
Experiment c. Observing the eye in accommodation. 
Apparatus and material; A pin stuck upright in the cork 
of a small bottle; a match mounted in the same manner. 
Procedure: Set the bottle with the pin eight inches from 
the eye of the person acting as the subject of the experiment. 
At a distance of two yards set the match on a level with the 
pin. Let the subject first view the match with the right eye 
only, keeping the pin in line with the match. Let the ob- 
server then take a position on the right of and a little behind 
the subject, and tell him to focus from the match to the pin. 
While the subject does this let the observer watch the iris of 
the eye. As the lens bulges out in changing from far vision 
(looking at the match) to close vision (looking at the pin), it 
pushes the iris out also. The bulging out of the iris may be 
observed in the experiment. 
Notes : Write up this experiment. 
EXERCISE 90. OPTICAL DEFECTS. (CLASS WORK) 
Experiment a. Tests of vision. 
Apparatus and material: A number of Snellen's test cards, 
which may be obtained from a druggist or optician. THE SPECIAL SENSES 
115 
Procedure: Test the pupils for far- and near-sightedness 
according to the directions on the cards. 
Experiment b. Astigmatism. 
Material: The appropriate figure on Snellen's test cards. 
Procedure: Let the pupil look at the parallel lines of the 
figure with which to test for astigmatism. If any of the lines 
look indistinct or run together, astigmatism is present. 
Notes: Make a record of the optical defects found among the 
members of your class. 
EXERCISE 91. OPTICAL ILLUSIONS. (HOME WORK) 
Experiment a. Deception due to habit. 
Material: A sheet of stiff writing paper. 
Procedure: Roll the paper in the form of a tube about an 
inch in diameter. With the left eye, look through the tube 
towards some bright object, such as the sky. Cover the right 
eye with the right hand. Give close attention to the tube 
and incidental attention to the hand. There will seem to be 
a hole through the hand. 
Notes: Write up this experiment. 
Experiment b. Other illusions. 
Material: Ritchie, Fig. 128; a pair of scissors ; an old wall 
calendar having figures at least one inch high; paste or mu- 
cilage ; cardboard. 
Procedure: Cut out a half dozen figures "8 " from the calen- 
dar and paste them in a row on a piece of cardboard. Look 
at the figures right side up and note that the upper loop of 
the 8 looks almost as large as the lower loop. Turn the card 
upside down and note the effect. (Letters S cut from ad ver- 116 
LABORATORY MANUAL 
tisements in a newspaper will do as well as figures " 8.") 
(Study also Ritchie, Fig. 128.) 
Notes: Write up these experiments. 
EXERCISE 92. THE BLIND SPOT. (HOME WORK.) 
Apparatus and material: A sheet of paper and a pencil. 
Procedure: Place a small cross on a sheet of paper and a 
plain black dot three inches to the right of the cross. Close 
the left eye and look at the cross with the right eye. Hold 
the paper about ten inches from the eye. Move the paper 
farther from or nearer to the eye, always looking at the cross, 
until the image of the dot disappears. 
Review Exercise 88, b. In studying the eye it was observed 
that there is no retina where the optic nerve penetrates the 
eyeball to spread over the retina. 
Notes: Write up this experiment and show how it proves that 
there is no retina at the blind spot. SECTION XIII. THE BACTERIA 
EXERCISE 93. FERMENTATION AND DECAY. (CLASS WORK) 
Suggestion: The preparation of the cultures described in 
this exercise may be assigned to different pupils or groups 
of pupils. The teacher may mount specimens from each 
culture for study under the microscope. 
Experiment a. Yeast. 
Apparatus and material: The apparatus used in Exercise 
3, b, Fig. 2. 
Procedure: Set aside the culture in a warm place and 
await results. The liquid in the bottle will be displaced by a 
gas, CO2, produced by fermentation of the sugar in the mo- 
lasses. The sugar of the molasses is attacked by digestive 
enzymes produced by the yeast cells and broken down into 
alcohol, acid, and CO2. The CO2 escapes as a gas (note the 
bubbles) and fills the inverted jar. Taste the fermenting 
solution : it is sour from the acid. Smell the solution : you 
can detect the odor of alcohol. Remove the jar and lower 
a lighted match into it: the match is extinguished. (Com- 
pare Exercise 3, b.) Study the yeast plants under the mi- 
croscope as in Exercise 3, b. 
Notes: Describe the manufacture of alcohol, of vinegar, and of 
cider. What causes light bread to rise ? 
Experiment b. Bacteria in milk and vinegar. 
Apparatus and material: A small quantity of mother of 
vinegar (dregs from the bottom of apple or wine vinegar); 
a small quantity of sour milk; microscope; slides and cover 
glasses. 
Procedure: Study the bacteria of vinegar and of milk 
under the high power of the microscope. The bacteria can 
be seen more plainly under an oil-immersion lens, which 
117 118 
LABORATORY MANUAL 
should be used if available. The bacteria are much smallei 
than the oil globules of milk and are seen to be in an active, 
vibrating motion. In both the vinegar and the milk they are 
of the rod-shaped kind called bacilli (Ritchie, Fig. 141, A). 
In studying the living bacteria care should be taken to regu- 
late the light which passes through the diaphragm of the 
microscope, as the bacteria are not visible if there is too little 
or too much light. 
Notes: Review Exercise 32, b. Compare the fermentation (sour- 
ing) of milk with the fermentation of molasses by yeast. 
Experiment c. Decay. 
Material: A piece of decaying meat; slides and cover 
glasses; microscope. 
Procedure : Mount scrapings from the meat on a slide and 
note the bacteria. 
Notes: Certain bacteria cause decay as others cause fermenta- 
tion. Putrid odors accompany decay. Decay results from decom- 
position of proteins, whereas fermentation results from decomposition 
of carbohydrates, such as starch in dough and sugar in molasses, 
milk, etc. The products resulting from decaying proteins such as 
meats, fish, or milk are especially harmful to the body and often pro- 
duce ptomaine poisoning. 
Make a list of foods which one must be especially careful to secure 
fresh and pure. 
Experiment d. To show that fermentation is due to living 
things. 
Apparatus and material: A half-pint bottle of grape juice; 
a tumbler; a stewpan of water. 
Procedure: Open the bottle of grape juice. Pour out half 
the contents into the tumbler, which should be left uncovered. 
Recork the bottle containing the remainder of the grape THE BACTERIA 
119 
juice and heat it for fifteen minutes in water boiled in a stew- 
pan. Set both the open tumbler and the closed bottle in a 
warm place and await results. 
Notes: Explain the results of this experiment. 
Experiment e. Hay infusion. 
Apparatus and material: A handful of hay; stewpan of 
water ; microscope ; slides and cover glasses. 
Procedure: Prepare a hay infusion or hay "tea" as fol- 
lows : Chop a handful of hay into small pieces and steep 
them in boiling water. Set the infusion aside in a warm 
place; then study the bacteria that appear in it. 
Notes: What do the bacteria live on in the hay infusion ? Where 
do you now think bacteria are found in nature ? 
Experiment f. Infusion of algae. 
Apparatus and material: Microscope; slides and cover 
glasses ; an 'aquarium or other vessel filled with water algae, 
such as pond scum (Spirogyra) or Rockwort (Chara). The 
pond scum is found on the surface of quiet ponds or puddles, 
is light green in color, and slimy to the touch. Rockwort is 
found at the bottom of large bodies of clear water, such as 
lakes or large "tanks." Other submerged water plants will 
also do for this experiment. The vessel should be over- 
stocked so that the plants will die and decay. 
Procedure: Set the infusion of algae aside in a warm place 
until decay sets in. Study a drop of water from the culture. 
Among the bacteria certain larger specimens should be visible 
which swim through the water with a spiral motion. These 
oacteria are called spirilla (Ritchie, Fig. 141, C). 
Notes: Sketch several spirilla and describe their movements as 
seen under the microscope. 120 
LABORATORY MANUAL 
EXERCISE 94. STAINING BACTERIA. (DEMONSTRATION) 
Experiment a. General. 
Apparatus and material: Slides and cover glasses ; a clean, 
soft rag; 10% hydrochloric acid; alcohol; distilled water; 
methylene-blue stain; alcohol lamp or Bunsen burner; micro- 
scope ; platinum loop or glass rod. 
Procedure: Clean several dozen cover glasses successively 
with 10 % hydrochloric acid, water, and strong alcohol. Rub 
them dry and warm them gently in a flame. (It is advisable 
to have a good supply of clean cover glasses for future use in 
experimenting, as no cover glass can be used a second time.) 
Place a drop of the medium containing the bacteria on a 
cover glass and spread it evenly over the surface. A plati- 
num wire with a loop at the end is the best thing to use in 
transferring bacteria. The wire should be sterilized each 
time by holding it in a flame. A glass rod, rounded at the 
end by holding it in a hot flame, will serve very well; it 
should also be sterilized in the same manner. The end of 
the rod or looped wire is immersed in the liquid and the drop 
adhering to it is placed on the cover glass and spread over it. 
The preparation is then allowed to dry. There is now a film 
of bacteria adhering to the cover glass. 
When dry, the bacteria are further " fixed " by passing the 
cover glass, film side up, slowly through a flame, care being 
taken to warm the cover glass thoroughly, but not to scorch 
the bacteria. Hold the cover glass in a pair of forceps while 
heating, and test its temperature by applying it to the back 
of the hand ; it should not be hot enough to cause pain. 
After fixing, the preparation is ready to stain. Hold the 
cover glass in a pair of forceps, film side up. Care should be 
taken to remember which is the film side, as it may be hard THE BACTERIA 
121 
to distinguish the two sides after staining. With a glass rod 
(used for this purpose only) transfer to the cover glass one or 
more drops of methylene-blue stain, spreading it evenly over 
the film. Leave the stain on for one minute ; then wash it off 
with distilled water. If stained too dark, leave the stain on 
a shorter period of time when staining the next specimen- 
The slide may now be laid on a piece of blotting paper and 
allowed to dry. 
To study the preparation with the microscope, the cover 
glass is mounted on a glass slide, film side down, either in a 
drop of water or a drop of Canada balsam, according as 
a temporary or a permanent preparation is desired. The 
bacteria may first be studied in water, so as to avoid get- 
ting fresh balsam on the objective of the microscope. If 
the preparation is a good one, the cover glass may be dried 
a second time and then mounted in balsam. Prepared slides 
may be kept from year to year, but several preparations 
should be made in the presence of the class. 
Suggestion: For practice in staining the bacteria, perhaps 
the best material to begin with is that scraped from the teeth. 
With a clean sterilized scalpel, scrape some of the "fur" 
from the teeth and spread it over a cover glass. Dilute it 
slightly with a drop of saliva if necessary. Fix and stain it 
as directed above. Various kinds of bacteria will be seen. 
(See b, below.) 
Notes: Describe the manner of preparing bacteria so that they 
may be better studied than in the living state. 
Experiment b. The three classes of bacteria. 
Apparatus and material: Those needed for staining bacteria 
(a, above); specimens from cultures described in Exercise 
93. These furnish bacilli and spirilla (Ritchie, Fig. 141); a 122 
LABORATORY MANUAL 
stained slide showing bacteria from the mouth; "pus" from 
a festering sore, boil, or pimple. 
Procedure: Fix and stain bacteria as directed. Study 
bacilli and spirilla as in Exercise 93, except that they should 
be stained. The bacteria of the teeth are of various kinds, 
including bacilli, spirilla, and cocci. The cocci (Ritchie, Fig. 
141) are rounded bacteria grouped irregularly and in chains. 
Such cocci are especially common in pus-forming bacteria com- 
mon in boils and pimples. (See Ritchie, Fig. 145, B and C.) 
Notes: Sketch various groups of cocci. 
EXERCISE 95. THE PREPARATION OF SPECIAL CULTURE 
MEDIA. (DEMONSTRATION) 
Suggestion: Several culture media have been described in 
Exercise 93. For special purposes, however, one of the two 
culture media here described will be found indispensable. 
The potato is easier to manipulate, while the agar is more 
satisfactory for most purposes. 
The only difficulty which the teacher will experience in 
carrying out this exercise lies in the sterilization by heat of 
the culture media and the dishes. But this difficulty is not 
insurmountable and the time, patience, and care required will 
be amply repaid by the highly instructive and enlightening 
character of the experiments. 
Lack of more expensive and convenient apparatus need not 
deter the teacher from undertaking the experiments here 
given as the cheaper and more readily available substitutes 
will suffice. Go over lists of apparatus carefully. 
The greater part of the work in preparing the culture 
media will, of course, fall upon the teacher; but the pupils 
may help in the routine work. A part of two Saturdays will 
suffice to get the culture media ready. THE BACTERIA 
123 
Experiment a. How to sterilize the dishes. 
Apparatus and material: Twenty Petri dishes (Fig. 24) or 
flat bottles which it is desired to sterilize ; cotton for plugs 
in the bottles, if these are used; hot-air sterilizer, or the oven 
of a gas stove or gasoline stove, or the ordinary kitchen 
oven. (If the potato culture only is used, the dishes need 
not be sterilized.) 
Procedure: Wash out the Petri dishes or the bottles 
thoroughly and allow them to dry perfectly. When perfectly 
dry wrap each dish or bottle in a piece of newspaper. (If 
bottles are used, they should first be tightly stoppered with 
cotton plugs, made by rolling the cotton into a firm, round 
mass just small enough to fit the neck of the bottle tightly, 
P"ig. 27.) If a hot-air sterilizer is available, heat the dishes 
or bottles for twenty minutes at 1600 C. (3200 F.). The 
oven of a gas or gasoline stove will, however, serve admirably 
as a hot-air sterilizer, should the special apparatus with 
thermometer not be available. Place the wrapped dishes 
in the oven. Place on the dishes a small piece of bread. 
When the heat rises to a point at which the bread begins 
to brown, turn the flame somewhat down and keep the 
oven at a temperature a little below that of baking for one 
half-hour When looking into the oven, open the door very 
slightly. At the end of a half-hour turn out the flame but do 
not open the door of the oven until the glass dishes have cooled. 
Experiment b. Sterilizing the culture media. 
Apparatus and material: The culture media in Petri dishes, 
tumblers, or flasks, prepared as described below; Arnold 
sterilizer (Fig. 23) or a canning apparatus. 
Procedure: To kill all trace of life in a culture medium, 
merely bringing it to boiling temperature (too0 C. or 2120 F.) 124 
LABORATORY MANUAL 
once is not sufficient. If an 
Arnold sterilizer is used, the 
medium is steamed for twenty 
minutes on three consecutive 
days, being kept in a warm 
room between sterilizations to 
start the spores into growth. 
Place water in the pan of the 
Arnold sterilizer and the vessels 
containing the medium on the 
shelves. On boiling the water 
the steam will rise throughout 
the apparatus. 
The canning apparatus will 
be found more convenient than 
the Arnold sterilizer as only 
one heating at fifteen pounds pressure (1200 C. or 248° F.) 
is necessary to kill bacteria. A temperature greater than 
ioo° C. (212° F.) can be attained only under pressure. Heat 
the medium for ten to fifteen minutes with fifteen pounds 
pressure in the canning apparatus. 
Experiment c. Preparation of potato medium. 
Apparatus and material: Petri dishes or glass tumblers; 
large potatoes (larger if Petri dishes 
are used)'; sterilizing apparatus (see b, 
above). 
Procedure: Peel several large po- 
tatoes and boil them until they are 
soft, yet firm enough to slice. With 
a clean knife cut about twenty slices 
one fourth of an inch thick, and place 
Fig. 23. Arnold steam sterilizer. Water 
is poured in the bottom B. The objects 
to be sterilized are placed on the shelves 
S, the door is closed, and the whole 
covered over by the hood; Sc, steriliz- 
ing chamber. 
SLICE OF POTATO' 
Fig. 24. A Petri dish, for 
raising cultures of bacteria on 
nutrient media. THE BACTERIA 
125 
them in the Petri dishes or glass 
tumblers (Figs. 24 and 25). If tum- 
blers are used, the slice should fit 
snugly in the bottom of each tumbler. 
The Petri dishes are merely covered 
with the lid, but the tumblers should 
be covered with a layer of cotton tied 
tightly over the top by means of a 
strong cord. Tie the cord in a bow- 
knot so that the tumbler may be 
readily opened later for inoculation. 
When once sterilized, the dishes should, of course, not be 
uncovered until the operator is ready to inoculate the culture 
medium. 
Experiment d. Preparation of nutrient agar medium. 
Suggestion : Agar is here recommended in preference to 
gelatine because it remains stiff at ordinary room temperature 
or even at a higher temperature. This simple culture medium 
may be prepared in the laboratory or in the home kitchen. 
The preparation merely consists in cooking nutrient matter 
under carefully controlled conditions. This medium is in 
many respects more satisfactory than the potato medium. 
Apparatus and material: A clean stewpan, containing 
1100 c.c. of water; 15 g. of agar; 3 g. of Liebig's extract of 
beef; 10 g. of Witte's pepton; white of one egg, well 
beaten; Erlenmeyer flask of 1250 c.c. capacity; a large 
funnel; a piece of wire gauze (screen wire cut into a disk 
about the size of a dollar); a large sheet of absorbent cotton 
to fit into the funnel; a sterilizing apparatus (see b, above). 
Procedure: Heat the pan of water. Cut pieces of agar 2 or 
3 inches long, shred them, and dissolve them in the hot 
COTTON 
-POTATO 
Fig. 25. Tumbler with thick 
sheet of cotton tied tightly over 
the top - a good substitute for 
Petri dishes for potato medium. 126 
LABORATORY MANUAL 
water. Boil the mixture gently and keep it stirred. When 
the agar is fully dissolved, add the beef extract and the 
pepton. Allow the mixture to cool so that the sides of the 
vessel may be touched with the fingers for a second. Then 
add the beaten white of an egg while stirring the liquids. 
Bring the liquid to a boil again and boil it from ten to fifteen 
minutes, stirring constantly, or better, 
heat it in the steam sterilizer for a 
half-hour. It must be thoroughly 
heated to coagulate all the albumin. 
Filter the solution while hot. To 
do this place the cotton over the 
funnel and press it down gently into 
the bottom of the funnel. Then wet 
the cotton with boiling water and pour 
in the hot agar, using care not to break 
the cotton at any point (Fig. 26). 
(Caution : The cotton should be sup- 
ported with the disk of wire gauze 
placed in the bottom of the funnel, 
and a small bunch of cotton should 
be laid in the mouth of the stem of 
the funnel.) Catch the filtered solu- 
tion (which should now be clear) in 
the Erlenmeyer flask, taking care not to get any of the 
solution on the mouth of the flask. Roll a mass of cotton into 
a firm stopper and fit it tightly into the mouth of the flask. 
The medium in the flask is now ready to be sterilized as 
directed in b above. After sterilization, the medium may 
be set aside and may be kept indefinitely. If ready at this 
juncture to pour the dishes, this should be done at once, as it 
will save remelting the agar later. 
FUNNEL 
RUBBER TUBE 
PINCH-COCK 
GLASS TUBE 
Fig. 26. Funnel arranged for 
running agar into test tubes or 
bottles. A, pinch cock attach- 
ment. THE BACTERIA 
127 
EXERCISE 96. POURING AND INOCULATION OF DISHES OR 
BOTTLES. (CLASS WORK) 
Apparatus and material: The nutrient agar prepared as 
directed above; a stewpan with water, large enough to boil 
the flask of agar medium; 16 of the sterilized Petri dishes or 
bottles; a small sample of the milk and the water to be 
tested; a sample of washings from a drinking cup (the edge 
Fig. 27. A flat bottle which may be used instead of Petri dishes for agar. The mouth 
of the bottle is closed with a tightly rolled plug of cotton. 
of a drinking cup is washed with a little water and a sample 
of this is used in the experiment); pipette or eye dropper; 
5 % carbolic acid ; 16 labels. 
Procedure; Place the Petri dishes or bottles in a row near 
the edge of the table. If bottles are used, lay them on the flat 
side, using them like Petri dishes. Write on labels one of the 
following legends and place the labels each on its own bottle : 
(a) Bacteria in water. 
(Z>) Bacteria from milk. 
(r) Bacteria from drinking cup. 
(</) Bacteria from finger nails. 
(<?) Bacteria from teeth. 
(/) Bacteria from breath. 
(g) Bacteria from air of a clean room. 
{h} Bacteria from a dusty room. 
(/) Bacteria from open air. 
(7) Bacteria from schoolroom. 128 
LABORATORY MANUAL 
(£) Fly's promenade. 
(Z) Bacteria drying. 
(z«) Bacteria from air-compare with (zz). 
(zz) Bacteria on ice - compare with (m). 
{o') Bacteria and light - compare with (m). 
(/) Bacteria and carbolic acid. 
Into (a) place 2 c.c. of the sample of water; into (b) place 
1 c.c. of milk; into (c) place 1 c.c. of washings from the 
drinking cup; into (/) place 10 c.c. of 5% carbolic acid. 
Measure the liquid with an ordinary pipette or eye dropper 
sterilized each time before using. 
All the dishes (or bottles) are now ready for pouring and 
inoculation {a, b, and c are already inoculated). 
If the agar has been allowed to solidify in the flask, it 
must be melted by heating. Boil the flask in a stewpan of 
water until the agar is thoroughly liquid. Allow it to cool 
until the flask can be handled with comfort. Do not pour 
dishes {a), {b), and {c) at this time. As the flask is heavy an 
assistant should aid in the pouring of the dishes. Let the 
assistant raise one edge of the dish and hold it in that position 
until agar has been poured into the dish to the depth of one 
sixth to one fifth inch. The assistant then lowers the lid (which 
should, of course, not be raised again except to inoculate the 
agar). If bottles are used, remove the cotton stopper, pour 
agar into the bottle, and then lay the bottle on its side again. 
While the agar is still liquid, the dish or bottle is tilted back 
and forth until the agar completely covers the bottom of the 
dish (or flat side of the bottle). Each dish or bottle, (^)-(/), 
is poured in this way. Dish (or bottle) (/) should have the 
agar and the carbolic acid solution thoroughly mixed. 
Now allow the agar in the flask to cool until one can just 
endure having the flask held to the cheek. The agar will THE BACTERIA 
129 
still be liquid at this temperature. Now pour dishes (or 
bottles) (zz), and (r), mixing the water or milk and the 
agar thoroughly. 
Dishes («), (b\ and (f) are now ready to set aside. 
The pupils may be assigned the dishes for inoculation ac- 
cording to the directions given below. Care should be taken 
to inoculate each dish after the manner indicated by the label 
on the dish. After each inoculation, replace the lid (or the 
plug of the bottle). 
Reference will be made below only to Petri dishes, it being 
understood that if bottles are used in place of the dishes, as 
nearly as possible the same method will be used in inoculat- 
ing the bottles as is recommended for the dishes. On ac- 
count of the small size of the mouth of the bottle exposure 
to the air should be five times as long for the bottles as for 
the dishes. 
Bacteria from the finger nails (d). Clean the finger nails 
with a toothpick (which may first be sterilized by scorching 
slightly) and run the infected toothpick in a streak over the 
agar of the Petri dish (d). (A longer stick will be needed to 
inoculate the bottle.) 
Bacteria from the teeth (^). Rub another sterilized tooth- 
pick (or longer stick) over the teeth to collect bacteria. In- 
oculate the agar of Petri dish (^) as before. 
Bacteria in the breath (/). Blow or cough over the sterile 
agar of Petri dish (/); then close the dish at once. 
Bacteria from the air (^). Remove the lid from the ster- 
ilized Petri dish (£•) and expose the agar to the air of a clean 
living room for five minutes. 
Bacteria from dust {h). Sweep the floor with a broom 
and expose Petri dish (/z) to the air and dust for five 
minutes. 130 
LABORATORY MANUAL 
Bacteria from the open air (z). Expose dish (z) to the air 
out of doors for five minutes. 
Bacteria from schoolroom (/). Expose sterile dish (y) to 
the air of the schoolroom after this has been occupied for 
some hours. 
Flies and bacteria (k\ Capture a housefly in a vial and 
allow it to crawl out into Petri dish (£) by holding the mouth 
of the vial under the lid of the dish and quickly dropping the 
lid over the fly when it emerges from the vial. Imprison the 
fly in the dish until it has walked over the agar several times. 
Then set the fly free by raising the lid a little on one side. 
In all these operations care should be exercised to prevent 
infection of the agar by air-borne bacteria. 
Moisture needed by bacteria (Z). Open Petri dish (z) and 
leave the lid off. The object of this experiment is to test 
the effect of drying on the growth of bacteria. 
Effect of temperature and light (zzz), (n), and (o). Expose 
Petri dishes (zzz), (zz), and (o) to the air of a room for five minutes. 
Replace the lids. Keep (m) at ordinary temperatures with 
the other cultures; place (zz) on ice at once and keep it cold 
throughout the experiment; expose (o) to the direct rays of 
the sun as much as possible. Compare (m), (zz), and (t?) care- 
fully from day to day. A comparison of (zzz) and (zz) should 
show the effect of cold on the growth of bacteria; a compar- 
ison of (zzz) and (o), the effect of light. 
Effect of disinfectant (/). Expose dish (/) to the air of 
a room for five minutes. 
All of the inoculated Petri dishes (except (zz) and (o)) are 
to be set aside in a drawer or other dark place and kept at 
room temperature. 
(If any of the culture medium is left over in the flask and THE BACTERIA 
131 
if it is desired to keep it for further experiments, it must be 
sterilized again, since it has doubtless become infected from the 
air during the large number of pourings that have been made.) 
Another method of procedure is to pour the agar into 
small bottles or test tubes (enough in each to make one plate) 
immediately after filtering. These are then stoppered with 
cotton and sterilized, and, when wanted for plating, the agar, 
can be melted by setting the test tubes in hot water. In case 
flat bottles are used for plating, the agar can be run directly 
into them and sterilized in the bottles. In making plates 
of water, milk, etc., in Petri dishes, the material can be mixed 
with the agar in the bottles or test tubes and then poured into 
the dishes. Follow the directions already given for cooling 
the agar; for if it is used when too hot, the bacteria will be 
killed. In case no sterilizer is available these small amounts 
of media may be rendered sterile by setting them in boiling 
water for 20 minutes for three successive days. 
Notes : Write up the notes as directed in Exercise 98. 
EXERCISE 97. INOCULATION OF POTATO CULTURES. (CLASS 
work) 
Apparatus and material: Potato culture medium in tum- 
blers ; other material, except the culture medium, as in 
Exercise 96. 
Procedure: If potato is used for the culture medium, all 
the experiments, (a) to (0), outlined above, may be made on 
this medium without variation except (a), (£), and (c). In 
these experiments drops of water or milk may be placed on 
the potato instead of being mixed with it. The results will 
be found striking, though not quite so satisfactory as with 
agar. 132 
LABORATORY MANUAL 
EXERCISE 98. STUDYING THE CULTURES. (CLASS WORK) 
The 16 bacterial cultures, («) to (/), inoculated as described 
above, should now be studied from day to day and careful 
notes on them kept. Describe exactly what you see. Con- 
tinue the observations for three or four weeks. In two days 
colonies of bacteria should be plainlv visible. Every particle 
of dust that falls upon the exposed agar carries one or several 
bacteria, which soon begin to multiply at the expense of the 
nutrient agar. One bacterium is invisible to the naked eye'; 
but when one develops into a colony of thousands, they 
become visible. Each colony is, therefore, a collection of 
thousands of bacteria. Note the color and shape of the 
colonies. Note those that grow deep and those that grow on 
the surface. 
EXERCISE 99. QUESTIONS FOR STUDY. (HOME WORK) 
The following questions will be found helpful in the study of the 
cultures. The letters in parentheses refer to the experiment designed 
to answer the question. 
How do we know that living things (bacteria, yeast, etc.) cause 
fermentation and decay (Exercise 93, a) ? What do we mean by 
sterilization? What harmful bacteria are likely to be present in 
drinking water ? (Ritchie, page 328) ? How many bacteria did you 
find in 2 c.c. of water ? Can you count them (0) ? Why is it impossible 
to get milk absolutely free from bacteria communicated by the milk- 
man (^) ? How do bacteria get into milk (g, h, £)? Why should 
the milk vessels be thoroughly scalded ? What measures would you 
recommend to a dairyman to insure clean milk? How may harmful 
bacteria get into milk (Ritchie, pages 330-331)? How may you catch 
diphtheria from a public drinking cup (r)? Why is it dangerous to 
scratch a sore with the finger nails (,/) ? Why should the hands be 
washed with soap and water before each meal? Discuss the care THE BACTERIA 
133 
of the teeth (<?). Why is it dangerous to pass an apple around 
so that each person may take a bite (/)? How may a consumptive 
scatter germs (/)? How are the common bacteria scattered (g, A)? 
Discuss the dangers of dry sweeping (^). Why are carpets not sani- 
tary 0, /) ? Why are there fewer bacteria out of doors than indoors 
I, o\> How do flies carry bacteria (£; also Ritchie, Fig. 154)? 
Why are dark, damp tenements said to "breed disease" (Z, <?)? 
Why do canned goods " keep " (Exercise 95, a'i ? Why are refriger- 
ators used («)? APPARATUS, MATERIAL, FORMULA, ETC 
APPARATUS 
FIRMS FURNISHING LABORATORY SUPPLIES 
Bausch and Lomb Optical Company, Rochester, New York. 
Microscopes, apparatus, slides, and chemicals. 
Spencer Lens Company, Buffalo, New York. 
Microscopes, apparatus, slides, and chemicals. 
Central Scientific Company, 345 W. Michigan Ave., Chicago, Illinois 
Apparatus and chemicals. 
L. E. Knott Apparatus Company, Harcourt Street, Boston, Massa- 
chusetts. Apparatus, slides, and models. 
Kny-Scheerer Company, 225 Fourth Ave., New York City. 
Apparatus, slides, and models. 
APPARATUS INDISPENSABLE FOR CARRYING OUT THE EXPERIMENTS GIVEN 
IN THIS MANUAL 
One or more compound microscopes, each with two objectives, two 
eye pieces, double nose piece, iris diaphragm, and Abb£ con- 
denser. 
One hand lens (on tripod). 
One pair of scales or balances, with gram weights up to 100 g. 
at least. 
100 microscopic slides, 25 by 75 mm., medium thickness. 
1 oz. of cover glasses, 22 by 22 mm., square, medium thickness. 
2 laboratory thermometers, with both Centigrade and Fahrenheit 
scales. 
Apparatus for the " decomposition of water by electrolysis and the 
collection of gases in separate graduated tubes " (not over $2.00). 
(See Fig. 9.) 
Tape measure. 
Alcohol lamp. 
Aspirator bulb. A bulb from an ordinary aspirator such as is sold in 
drug stores will do. (See Figs. 15 and 16.) 
135 136 
LABORATORY MANUAL 
Rubber balloon or " squawker," probably best secured at a toyshop. 
(See Fig. 19.) 
Rubber tissue (sheet rubber), square meter (may be purchased from 
a dentist). 
Rubber tubing, pure rubber, elastic. 
Diameter 6 mm., 1 meter. 
Diameter 10 mm., 3 meters. 
Two glass Y-tubes, inside diameter of tubes 5 mm. 
Glass tubing (of soft glass, ductile after brief heating). 
Inside diameter 3 mm., 1 meter. 
Inside diameter 5 mm., 6 meters. 
Glass rods, diameter 4 mm., 2 meters. (A glass stirring rod is made 
of glass rod, cut 8 inches in length and rounded at the ends, by 
holding in a flame.) 
1 dozen pipettes, with rubber bulb, 2 c.c. capacity. 
A stewpan. 
Iron tripod, height about 240 mm. 
3 porcelain evaporating dishes, diameter 100 mm. 
1 large funnel, diameter 200 mm. 
1 small funnel, diameter 100 mm. 
3 thistle tubes. (See 1, Fig. 8.) 
2 diffusion shells, of parchment paper, diameter 38 mm., made to slip 
over bulb of thistle tube. 
Erlenmeyer flasks. (See Figs. 8, and 20.) 
Four (4) of 250 c.c. capacity. 
One (1) of 1000 c.c. or 1250 capacity. (The latter is used for 
sterilizing agar, Exercise 95, d.) 
Rubber stoppers, with two holes, to fit the small Erlenmeyer flasks. 
Test tubes (at least 12 for each student), best glass, medium thick- 
ness, 160 by 16 mm. 
One -halfdozen large test tubes. 
2 rubber stoppers, with one hole, to fit the large test tubes. (See 
Fig. 10.) 
1 hacksaw with fine teeth, for sawing bones, etc. APPARATUS, MATERIAL, FORMULAE, ETC. 
137 
i flat file, for filing teeth. 
i three-cornered file, for scratching glass. (A glass tube or a glass 
rod is broken by first scratching the glass on one side and then 
snapping it in two by pressing gently on the opposite side.) 
i meter parchment tubing for diffusion experiments. 
Fine insulated copper wire, 5 meters. 
1 roll picture wire. 
Absorbent cotton, 1 pound. 
Snellen's test cards (may be bought from a druggist or from an 
optician). 
DESIRABLE APPARATUS AND SUGGESTED CHEAPER SUBSTITUTES. (THE 
SUBSTITUTES, AT LEAST, ARE INDISPENSABLE) 
Human skeleton. If the school cannot purchase a skeleton, it 
may perhaps be able to borrow one from a physician for a few days. 
If a human skeleton is not available, the skeleton of a cat prepared as 
directed in Exercise 9, b, will be found very helpful. Dried skulls 
and other parts of animal skeletons found in the fields should be col- 
lected and preserved. 
Dissecting instruments. a. Bone forceps, a strong scissor-like 
instrument for cutting bone. A strong pair of scissors is a good 
substitute, b. Scalpel. A highly sharpened pocketknife may be 
used instead of a scalpel, c. A pair of dissecting needles. These 
may be prepared out of butcher's skewers (rods of hard wood) and 
large cambric needles. The ends of the skewers are soaked in water 
over night. The needle is placed in an iron vise, point down, and the 
skewer is driven on to the needle with a hammer, d. Pair of forceps. 
Earthenware jar, capacity 5 gallons, with lid, for chloroforming 
animals. A tight box of convenient size will serve the purpose. 
Pithing needle. To make this, mount a large darning needle in a 
wooden handle, driving the wood on to the point of the needle. 
Heat the needle red hot in the middle and bend it at an angle of 138 
LABORATORY MANUAL 
about 450. With this the brain and spinal cord of a frog is de- 
stroyed. A bent wire may be used. 
Section razor, which is hollow ground on one side only. A very 
sharp knife may be used instead. 
Sheet cork, 5 pieces. The sides of a cigar box will do very well 
instead. 
Dissecting board: a simple board, 1 by 2 feet. A screweye 
should be screwed into each corner of the board. The animal to be 
dissected is stretched out on the board and its legs are tied to the 
corners of the board. 
Dissecting trays with wax bottoms. These can be purchased 
complete, but may be made of pans or of pie plates into which a 
mixture of melted beeswax and paraffin, in the proportion one 
to four, is poured. 
Bell jar, with opening at the top for a cork. A large bottle pre- 
pared as directed in Exercise 63 will do as a substitute. 
Wide-mouthed bottles, of about 250 c.c. capacity. Empty pickle 
bottles may be used. 
Pneumatic trough, for collecting gases under water. In place of 
this a tin lid of a candy jar, prepared as directed in Exercise 26, a (1) 
will be found very convenient. Figure 8 illustrates the use of the lid. 
Dollar watch. This may be borrowed. 
Stop watch. This may be borrowed from an athletic manager. 
Funnel stand. This may be made of wood; for example, of a 
wooden triangle supported on three legs. 
Test tube rack. This may be made of a 2-inch board, 4 by 
12 inches. Along one edge a series of holes are bored of such size 
as to hold a test tube. Along'the other edge a row of wooden pegs 
about 3 inches high (for example, butcher's skewers) are placed 
i-if inches apart. Test tubes are inverted on these pegs to dry. 
Wire test tube holders. Instead of these, strips of paper will serve 
to hold the test tubes. The sheet of paper is folded into a strip APPARATUS, MATERIAL, FORMULAE, ETC. 
139 
about 4 inch wide. This is held tightly around the test tube in a 
way to avoid burning the fingers while heating the test tube over a 
flame. 
Mortar and pestle, for grinding solid chemicals. A piece of hard 
wood or a piece of sheet iron for a mortar and the head of a hammer 
for a pestle will work very well. 
Spirometer. Instead of this, a bottle, shown in Fig. 18 and used as 
shown in Fig. 17, is adequate. 
Arnold sterilizer. This is a handy apparatus for steaming culture 
media. A canning apparatus, in which culture media may be heated 
under pressure to a temperature above that of boiling water, is more 
convenient. Such a canning apparatus can, no doubt, be borrowed 
by the teacher for a day for the sterilization of the culture media. 
Hot-air sterilizer. Where this is not available, the oven of a gas 
or gasoline stove may be used as directed in Exercise 95, b, care 
being taken not to get the oven too hot. 
Bunsen burner. Where natural gas or gasoline gas is used, Bunsen 
burners will be at hand. Where no gas is available, a laboratory 
blowtorch, costing about $3 or less, will furnish a flame that may be 
used for heating liquids, bending glass, etc. The vessel containing 
the liquid may be set on a tripod over the flame. The teacher may 
learn how to use the blow-torch from a local tinsmith. 
Beakers. Six beakers, 250 c.c. capacity (these are of clear, thin 
glass suitable for heating liquids; they will not break when hot water 
is poured into them). Cheap tin cups may be used instead for heat- 
ing liquids (except acids) and ordinary glass tumblers for holding 
cold liquids. 
Petri dishes. Twenty Petri dishes, 100 mm. in diameter, best 
glass. (These dishes are the best to use for cultures of bacteria ; see 
Fig. 25.) Flat bottles of clear glass, such as one-half pint whisky 
bottles, Fig. 29 will answer for use with agar culture medium, and glass 
tumblers (Fig. 25) for use with potato medium. 140 
LABORATORY MANUAL 
MICROSCOPIC SLIDES 
(c. s. = cross section ; * = least necessary.) 
Cartilage 
*Connective tissue 
*Bone tissue 
*Striped muscle fibers 
*Smooth muscle fibers 
* Nerve 
Trachea (c. s.) 
Esophagus (c. s.) 
Stomach (c. s.) 
Small intestine (c. s.) 
Kidney (injected) 
Skin (scalp, c. s.) 
Ovary of cat 
Eggs of starfish (early cleavage 
stage) 
Hydra (c. s.) 
Earthworm (c. s.) 
*Trichina in pork 
BOOKS, BULLETINS, ETC. 
Ritchie's Human Physiology, World Book Co., Yonkers, New York. 
This high school text is referred to in the manual under the 
designation il Ritchie." 
Hartman and Bibb's The Human Body and Its Enemies (World 
Book CoA a grammar school text on Physiology, Hygiene, and 
Sanitation. 
Martin's Human Body, Advanced Course (Henry Holt and Co.), a 
550-page college text on physiology; deals also with Anatomy. 
Hough and Sedgwick's Human Mechanism (Ginn and Co.), an ad- 
vanced high school Physiology and Sanitation. 
Other textbooks by the World Book Co. on Hygiene and Sanitation 
will be found of service : Primer of Hygiene, by Ritchie and 
Caldwell; Primer of Sanitation, and The Primer of Physiology, 
by Ritchie; The First Book of Health, by Hartman and Bibb. 
The abridged Red Cross textbook on " First Aid," P. Blakiston's 
Sons Co., 1012 Walnut St., Philadelphia, Pennsylvania. 
The Annual Reports of your State Food and Drug Commissioner. 
The Bulletins of your State Board of Health. 
Your state sanitary laws and city health ordinances. APPARATUS, MATERIAL, FORMULAE, ETC. 
141 
MATERIAL 
SPECIMENS TO BE SECURED FROM THE BUTCHER'S SHOP 
Ball-and-socket joint 
Fresh bone (with periosteum) 
Ribs 
Heart 
Brain 
Eyes 
Teeth (human teeth may be se- 
cured from the dentist's office) 
CHEMICALS 
Acetic acid, glacial 100 c.c. 
Nitric acid, fuming 100 c.c. 
Hdyrochloric acid, concen- 
trated too c.c. 
Sulfuric acid 100 c.c. 
Chloroform too c.c. 
Alcohol, 95% 100 c.c. 
Formaldehyde 1000 c.c. 
Carbolic acid, crystals 25 g. 
Caustic soda 50 g. 
Caustic potash 25 g. 
Ammonia, concentrated 250 c.c. 
Copper sulfate 200 g. 
Potassium iodid 25 g. 
Iodine 25 g. 
Potassium chlorate 25 g. 
Black oxid of manganese 25 g. 
Mercuric oxid 25 g. 
Xylol 100 c.c. 
Canada balsam 25 c.c. 
Distilled water 
Saltpeter 25 g. 
Potassium chloride 25 g. 
Potassium ferrocyanid 25 g. 
Potassium bichromate 25 g. 
Sodium oxalate 25 g. 
Calcium oxid (for limewater) 25 g. 
Calcium chlorid 25 g. 
Sodium chlorid, pure 50 g. 
Lumps of zinc 5° g- 
Liebig's extract of beef 100 g. 
Pepton 25 g. 
Pepsin (Fairchild's) 50 g. 
Eosin 15 g- 
Carmin 25 g. 
Methyl-green D g- 
Fuchsin 15 g- 
Methylene blue 15 g* 
Agar 50 g. 
Rochelle salts too g. 
Wright's stains 25 g. 
Notebooks ; one for recording laboratory notes and one for lectures. 
Drawing pencils, hard and medium. 
Crayons, at least red, blue, and yellow. 
Ruler and eraser. 
Dissecting set (if pupil does his own dissecting), including scalpel, 
scissors, forceps, and pair of needles. 
APPARATUS FOR THE PUPIL 142 
LABORATORY MANUAL 
FORMULAE FOR STAINS AND OTHER SOLUTIONS, 
STAINS 
Aceto-carmine: Bring a 45 % solution of acetic acid to boiling point 
and add all the carmine it will dissolve. Filter when cool. 
Aceto-methyl green : Water, 100 c.c.; acetic acid, 1 c.c.; methyl- 
green, 1 g. 
Methylene blue: 
Solution A = 1 g. caustic potash in 10,000 c.c. (10 liters) of water. 
Solution B = saturated solution of methylene blue in 95 % alcohol. 
Add methylene blue to 50 c.c. of alcohol to excess. 
To make up the stain : take 70 c.c. of A and 30 c.c. of B. 
Wright's stain for blood: to be secured already prepared from the 
dealer (25 g.). 
SOLUTIONS, ETC. 
Iodine solution: 2 g. of potassium iodid are dissolved in 100 c.c. of 
water; then 1 g. of iodine is added and the solution is well 
shaken. 
Liquid soap mixture: 
Soft water 2000 c.c. 
Strong ammonia 150 c.c. 
Saltpeter 12 g. 
Hard soap 75 g. 
Fehling's solution: 
Solution A - 17.32 g. of copper sulfate dissolved m 250 c.c. of dis- 
tilled water. 
Solution A? = 62.5 g. sodium hydroxid and 86.5 g. of Rochelle salts 
dissolved in 250 c.c. of distilled water. 
For use, mix equal volumes of A and B. Keep the solutions separate 
until ready for use. 
Agar nutrient culture medium for bacteria. (See Exercise 95, d.) APPARATUS, MATERIAL, FORMULAE, ETC. 
143 
Ringer's solution : 
Water 1000 c.c. 
Sodium chlorid 7 g- 
Potassium chlorid 0.3 g. 
Calcium chlorid 0.25 g. 
Normal salt solution : 
Water 1000 c.c. 
Sodium chlorid 7 g. 
How to make a solution of a given per cent of concentration. 
(i) If the chemical is in a liquid form : Take as many c.c. of the 
chemical as the per cent called for. Use enough water to make 
100 c.c. Thus a 2 % solution of acetic acid is made of 2 c.c. of 
pure acetic acid and 98 c.c. of water; a 10^ solution of hydro- 
chloric acid is made by adding 10 c.c. of concentrated hydro- 
chloric acid to 90 c.c. of water. 
(2) If the chemical to be dissolved is a solid such as sodium hydroxid, 
sodium chlorid, etc. Add to 100 c.c. of water the same number 
of grams of the chemical as the per cent calls for. A 10% 
solution of sodium hydroxid is made by dissolving 10 grams 
of sodium hydroxid in 100 c.c. of water. 
THE METRIC SYSTEM AND SOME ENGLISH EQUIVALENTS 
THE METRIC SYSTEM 
io millimeters (mm.)= i centimeter (cm.). 
io centimeters = i decimeter (dm.)= 100 mm. 
io decimeters = i meter (m.) = 100 cm. = 1000 mm. 
1000 grams (g.) = i kilogram (kg.). 
1000 cubic centimeters (c.c.) = i liter (1.). 
i c.c. of water weighs i g. 144 
LABORATORY MANUAL 
SOME EQUIVALENTS 
i meter = 39.37 inches. 
1 inch = 2^- centimeters. 
1 liter = a little less than a quart. 
1 gallon = 4.54 liters. 
1 gram = 15^ grains. 
1 lb. = about kilogram. 
o° Centigrade = 320 Fahrenheit (freezing). 
ioo° Centergrade = 2120 Fahrenheit (boiling).