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POSIOLOGY 
WjiiJAM D. ZOETHOVT, Ph. D. Laboratory Manual 
OF 
PHYSIOLOGY 
fay 
WILLIAM D. ZOETHOUT, Ph. D. 
Professor of Physiology, Chicago College of Dental Surgery, 
Chicago, III. 
FOURTH REVISED EDITION 
Published by 
W. D. ZOETHOUT 
Chicago, Ill. 
1921 Copyright 1921 
by 
W. D. ZOETHOUT. TABLE OF CONTENTS 
Page 
PART I.-APPARATUS. 
Exp. 1. Galvanic or constant current 1 
Exp. 2. The faradic or induced current 3 
Exp. 3. Short circuiting the induced current 5 
Exp. 4. The kymograph 7 
Exp. 5. The electro-magnetic signal 7 
Exp. 6. The tuning fork 9 
PART II.-IRRITABILITY, CONDUCTIVITY, CONTRACTILITY. 
Exp. 7. Forms of stimuli 11 
Exp. 8. Stimulation by voltaic current 11 
Exp. 9. Strength of stimulus and height of contraction 13 
Exp. 10. Tetanus '. 13 
Exp. 11. Staircase; fatigue 17 
Exp. 12. Smooth muscle. Automatic action 17 
Exp. 13. Cilia 21 
Exp. 14. Reflex action 21 
Exp. 15. Reflex time 23 
Exp. 16. Reduction of nerve conductivity 23 
Exp. 17. Reflexes in the human being 27 
PART III.-THE BLOOD. 
Exp. 18. Hemolysis; permeability of corpuscle 29^ 
Exp. 19. To determine the osmotic pressure at which the hemoglobin is 
driven from the red blood corpuscle 33 
Exp. 20. Specific gravity of blood 33 
Exp. 21. Determination of number of red blood corpuscles 35. 
Exp. 22. Determination of white blood corpuscles 37 
Exp. 23. Sahli's hemoglobinometer 37 
Exp. 24. Blood quotient 37 
Exp. 25. Hemoglobin 39, 
I II 
TABLE OF CONTENTS 
PART III.-THE BLOOD-Continued. 
Exp. 26. Guaiacum test for blood 43 
Exp. 27. Hemin or Teichmann's crystals 43 
Exp. 28. Defibrinating the blood; fibrin, serum 45 
Exp. 29. Preventing coagulation 49 
PART IV.-CIRCULATION. 
Exp. 30. Anatomy of mammalian heart 51 
Exp. 31. Anatomy of frog's heart 53 
Exp. 32. Action of the heart 55 
Exp. 33. Graphic record of heart-beat 57 
Exp. 34. Effect of previous stimulation. Staircase 61 
Exp. 35. "All or Nothing" 63 
Exp. 36. Extra-systole; compensatory pause; refractory period 63 
Exp. 37. Transmission of cardiac excitation. The block 67 
Exp. 38. Influence of temperature on the heart 69 
Exp. 39. Action of chloroform and ether on the heart 69 
Exp. 40. Cardiogram. Cardiac impulse 73 
Exp. 41. Heart sounds 73 
Exp. 42. The pulse. Rate of pulse in various conditions 75 
Exp. 43. Pulse-tracing. The Sphygmograph 75 
Exp. 44. Blood pressure in man. The sphygmomanometer 77 
Exp. 45. Venous blood pressure 77 
Exp. 46. Capillary circulation 79 
Exp. 47. Hemodynamics 83 
Exp. 48. Cardiac inhibition 87 
Exp. 49. Reflex cardiac inhibition. Goltz's tapping experiment 91 
Exp. 50. Vaso-constrictor nerves 93 
Exp. 51. Vaso-motor mechanism. 95 
Exp. 52. Vaso-motor fibres in the cervical sympathetic 97 
Exp. 53. Action of mammalian heart 99 
Exp. 54. Blood pressure 107 
Exp. 55. Circulation time 119 
Exp. 56. Lymph hearts . 119 
PART V.-RESPIRATION. 
Exp. 57. Chest measurements during respiration 121 
Exp. 58. Respiratory capacity; the spirometer 123 
Exp. 59. Respiratory movements in man; the pneumograph 125 
Exp. 60. Artificial respiration. Schaefer's method 129 
Exp. 61. Factors influencing the respiratory center 129 TABLE OF CONTENTS 
III 
PART V.- RESPIRATION-Continued. 
Exp. 62. Pulmonary pressure 133 
Exp. 63. Respiratory sounds 133 
Exp. 64. Mechanism of respiration 135 
Exp. 65. The vagi nerves in respiration 137 
Exp. 66. Influence of acid and alkali on the respiratory center 141 
Exp. 67. Intra-thoracic pressure. Phrenic nerve..... 143 
Exp. 68. Reducing and oxidizing power of tissues 145 
PART VI.-ALIMENTARY CANAL. 
Exp. 69. Deglutition 147 
Exp. 70. Secretion of pancreatic juice 14 7 
Exp. 71. Peristalsis 149 
Exp. 72. Fat absorption 149 
Exp. 73. Rapidity of absorption and secretion 151 
Exp. 74. Auto-digestion 151 
PART VII-SWEAT AND URINE. 
Exp. 75. Secretion of urine 153 
Exp. 76. Secretion of sweat 153 PART ONE 
Apparatus 
Exp. 1-Galvanic, Voltaic or Constant Current. 
Apparatus:-Plug-key, wire, simple key, litmus paper. 
Insert the plug-key in the socket marked "Stimulating Current." Connect 
one of the wires of the plug-key with a simple electric contact key and attach 
wires as indicated in Fig. 1. The ends of the wires should be bright and all 
contacts made firm. 
(a) When you have set up the apparatus as directed, proceed as follows: 
Moisten a strip of blue litmus paper with physiological salt solution (0.7% 
NaCl). Lay this on a clean glass plate and hold the two electrodes on 
the paper about % cm. apart. Close the key and let the current flow for 
say one minute. Notice the change in color at one of the electrodes. Which 
one ? 
Fig. 1. Arrangement for galvanic current, a and a, plug-key; b, simple key; c, electrodes. 
(6) Repeat the above with red litmus paper. Result? Explain fully (a) and 
(b). Of what value is this? 
(c) Place the electrodes on the tongue; close the key and keep it closed for 5 
or 6 seconds. Effect? Was the shock stronger at make or break or during 
the passage of the current? 
1 3 
MANUAL OF PHYSIOLOGY 
Exp. 2-The Faradic or Induced Current. 
Apparatus:-Plug-key, wire, key, induction coil, platinum electrodes. 
The important parts of the induction coil are the primary coil (inner eoil) 
and the secondary coil (outer coil). Note that there is no metallic connection 
between them. Hence any galvanic current passing through the primary can 
not enter the secondary coil. 
Also notice the binding posts on the head piece to which the primary coil 
is attached. The horizontal metal bars with which the ends of the secondary 
coil are connected end in two binding posts. Notice the short-circuiting key 
near these binding posts. 
Fig. 2. The induction coil, a, plug-key; key; c, electrodes; d, primary coil; e, secondary coil. 
{a) Arrange apparatus as indicated in Fig. 2, connecting the wires of the stim- 
ulating circuit (primary circuit) with the binding posts on the inductorium 
marked single induction shocks (the left hand and central binding posts 
of the machine of The Harvard Apparatus Company). Open the short- 
circuiting key. Draw secondary coil away from the primary coil (about 
12 cm.). Place the electrodes on the tongue; close the key in the primary 
circuit, keep it closed for about 3 seconds; open the key; if there is no ef- 
fect, push the secondary coil one cm. closer to the primary and repeat. 
Continue this process until at a certain place a shock is felt when the key 
in the primary circuit is opened (this is called the "break" induction 
current). Is there any faradic current during the flow of the galvanic 
current through the primary coil? Bring the secondary coil gradually 
closer to the primary coil and repeat. Before any other results take place, 
the "break" shock may become too painful. You will proceed as fol- 
lows : 
1. Key open, electrodes on the tongue. 
2. Close the key. 
3. Take electrodes from the tongue and after that break the current. This 
will prevent you from taking the break shock. In this manner deter- 
mine the first point where the slightest "make" shock can be felt. 
Record these points. 
(&) If the induction coil you have is so constructed that the secondary coil 
can be rotated either on a horizontal or vertical axis, determine what ef- 
fect such rotation has on the strength of the induced current. 
In what ways can the strength of the induced current be varied ? 5 
MANUAL OF PHYSIOLOGY 
(c) Repeated Induction Shocks. The shocks obtained in (a) are sometimes 
spoken of as single induction shocks. By an arrangement found on the 
front of the induction machine, the galvanic current in the primary cir- 
cuit can be made and broken automatically and at every such make and 
break an induction shock is obtained. Connect the plug-key with the in- 
duction coil as shown by the instructor. On closing the key in the primary 
circuit, the galvanic current magnetizes the iron rod and thereby draws 
the spring away from the point of contact and the current is broken. 
Place the electrodes between thumb and finger (sec. coil at about 6 or 
8 cm.) and notice the succession of induction shocks. These are called 
"repeated induction shocks." Trace the current from the plug-key through 
the primary coil of the inductorium, back to the plug-key. Make a 
diagrammatic sketch of the inductorium showing the various binding posts, 
Ihe two coils and the automatic interrupter. Indicate also which binding 
posts are used for single and which for repeated induction shocks, and by 
means of arrows indicate the pathway of the current. 
Exp. 3-Short Circuiting the Induced Current. 
Apparatus:-Same as in Exp. 2. 
Set up apparatus for single induction shocks [Exp. 2 (a)]. Place secondary 
coil at about 9 cm. Close key in primary circuit and a break and perhaps 
also a make induction shock will be felt if the electrodes are placed on the tongue. 
Now close the short circuiting key found on the inductorium and having the 
electrodes on the tongue close and open the key in the primary circuit. Bid 
you obtain any induction shocks? Why? Trace the induced current. 
(a) Frequently it is necessary to employ only make induction shocks. This 
can be accomplished in the following manner:- 
1. Place the electrodes on the tongue, have the short circuiting key open, 
close the key in the primary circuit (the secondary coil must be close 
to the primary coil). Notice effect. Keep electrodes on the tongue. 
2. The electrodes being on the tongue, close the short circuiting key and 
break the primary circuit. Any break shock felt? Why? Repeat this 
until you are familiar with it. If you did not obtain a make induction 
shock, increase the strength of the induced current. 
(6) If only break shocks are wanted, how would you proceed? Prove it by 
experiment. N. B.-Remember the break shocks are stronger than the 
make shocks. 7 
MANUAL OF PHYSIOLOGY 
Exp. 4-The Kymograph. 
Apparatus:-Kymograph. 
Study the following: 
(a) How to wind the clockwork, 
(&) How to regulate the speed of the drum (two methods), 
(c) How to mount and smoke the paper on the drum, 
(cZ) How to label your tracings, (See below) 
(e) How to varnish (fix) and dry the tracing. 
Note on labeling the tracing. If the experiment calls for "Individual Trac- 
ing," each student in the group must procure the tracing for his note book. 
If a "Group Tracing" is wanted, one tracing for the whole group (but bear- 
ing the names of all members participating in the experiment) is sufficient; 
one of the members of the group places this tracing in his note book and the 
others make mention of this in their books. 
Each tracing must be labeled as follows:- 
L Proper lettering (a, b, c, etc.) in the individual curves, showing the 
characteristic parts of the curve, so you can call attention to these 
in your description, 
2. Proper legend, stating the nature of the curve, 
3. Your name, 
4. Date, 
5. No tracing is to be placed in the note book before it has been approved 
by the instructor. The tracing is to be permanently attached (not by 
clips) at the proper place in your note book. 
Exp. 5-The Electro-Magnetic Signal or Time Marker. 
Apparatus:-Electro-magnetic signal, key, kymograph, stand and clamp 
holder, plug-key, wire. 
(a) The signal magnet consists of two coils of wire above which is placed a 
flat piece of iron. When the galvanic current passes through these coils, 
the iron cores inside of the coils become magnetized and the iron plate 
above them is drawn down, remaining in this position until the current 
is broken. This causes the arm attached to the plate to move up and down 
and if a writing lever is attached to this arm the movements can be re- 
corded on the kymograph. 
(6) Place the signal magnet on a stand; attach a lever; adjust, by cement, a 
writing pen; connect with the "clock current," inserting a simple key. 
Smoke the paper on the kymograph; adjust the pen of the signal magnet 
on the paper. Let the drum revolve at a medium speed, close the key 
and record seconds. Notice the tracing; label it: "Time in seconds." 
How many millimeters did the drum move in 10 seconds? Increase the 
speed considerably and repeat. Individual tracing. 9 
MANUAL OF PHYSIOLOGY 
Exp. 6-The Tuning Fork. 
Apparatus:-Kymograph, tuning fork and starter, stand and clamp holder. 
This tuning fork makes 300 double vibrations per second. Mount it on a 
stand and by means of the "starter" set it vibrating. Attach a writing point 
to one of the prongs of the fork; let the pen of the fork write on the drum and 
start the fork (fastest speed of drum). In order to obtain sufficient speed, it 
may be necessary to twirl the drum by hand (ask for instructions). When you 
have obtained a good tracing label it "Time in 1/100 sec." Varnish it. How far 
did the drum move in 14 second? How many hundredths of a second to the 
centimeter? Individual tracing. PART TWO 
Irritability, Conductivity, Contractility 
Exp. 7-Forms of Stimuli. 
Apparatus:-Pithing needle, glass plate, frog, heavy wire, .8% NaOH in 
physiological salt solution. 
Pith the brain and spinal cord of a frog and dissect the gastrocnemius muscle 
with the sciatic nerve and the femur according to directions given by the in- 
structor. Be very careful not to injure either the muscle or its nerve and keep 
them moist with 0.7% NaCl solution. Unless otherwise stated a muscle-nerve 
preparation consists of the gastrocnemius muscle, the sciatic nerve, and the 
femur. A muscle preparation consists of the gastrocnemius muscle and the 
femur. 
Using the muscle as an indicator, determine whether the following stimuli 
affect the nerve:- 
(a) Thermal-apply a thick hot wire to the cut end of the nerve. 
(&) Mechanical-cut off the end of the nerve. 
(c) Chemical-dip the end of nerve in dilute NaOH solution. 
(d) Electrical-take up in the next experiment. 
Exp. 8-Stimulation by the Voltaic Current. 
Apparatus:-Kymograph, simple key, muscle holder and lever, wire, weights, 
stand, holders, frog, plug-key. 
Make a muscle preparation. Place it in the muscle holder, attach the lever 
(use a small weight to slightly stretch the muscle). Connect one of the wires 
of the plug key with a simple key and from there make connection with bind- 
ing post of the muscle holder. Wind a very thin copper wire around the ten- 
don and connect this with the other wire of the plug-key, but do not let the 
weight of the heavy wire drag on the lever (wind the heavy wire around the 
stand). Ascertain that the pen writes correctly on the slow drum. 
Close the key and keep it closed for about three seconds; open the key. 
Most likely two contractions (twitches) are obtained. Do they differ in size? 
What three physiological properties of the muscle were here brought into 
play? Define each of them. Individual tracing. 
11 13 
MANUAL OF PHYSIOLOGY 
Exp. 9-Strength of Stimulus and Height of Contraction. 
Single Make and Break Induction Shocks. 
Apparatus:-Kymograph, stand, muscle clamp and lever, key, induction coil, 
frog, plug-key, wire. 
Set up apparatus for single inducton shocks (Exp. 2). Use the muscle prep- 
aration of Exp. 8; connect this in the secondary circuit. Place secondary coil 
as far from primary as possible and stimulate the muscle by closing the key; 
let the key remain closed for 2 or 3 seconds (stationary drum). If a con- 
traction occurs, move the drum forward a little, so that the contraction writes 
a vertical line, and no two contractions are superposed. Break the current. 
After each break move secondary coil one half cm. nearer to the primary' coil 
and wait one minute before the next contraction is made. When the induced 
current is strong enough, a make or break contraction appears. Continue to 
increase the strength of the induced current till the secondary and primary 
coils are flush. Below the curves write M and B, and also the distance between 
the primary and secondary coil. Group Tracing. Note the minimal break con- 
traction. What point of the irritability does this give? Note the first maximal 
contraction. What can you say of the strength of the make and break induc- 
tion shock? Discuss the height of contraction. Plot a curve showing relation 
between the strength of the stimulus and the height of the contraction, using 
the distance between secondary and primary coils as abscissae and the height 
of the tracing in millimeters as ordinates. 
Which of the four forms of stimuli listed in Exp. 7 do you regard as the 
most efficient and most practical ? Give four reasons for this. 
Exp. 10-Tetanus. 
Apparatus:-Same as in previous experiment. 
Perform this experiment, if possible, with the same muscle used in the previ- 
ous experiment. Connect the plug-key with the inductorium, so as to obtain 
repeated induction shocks. Slow moving drum. Close the key and record a 
stretch of tracing. Individual tracing. What is the relation between this 
curve and that obtained by a single induction shock? 17 
MANUAL OF PHYSIOLOGY 
Exp. 11-Staircase and Fatigue. 
Apparatus:-Same as in Exp. 9. 
(a) Set up induction coil for single shocks. Make a muscle preparation, place 
it in the holder and connect it with the secondary coil. Use a load from 
30 to 60 grams, depending on size of muscle. Draw a base line clean 
around the drum. For the first dozen stimulations use the break shocks 
only (why?) ; after that both makes and breaks may be used. 
(b) With drum moving fairly slowly stimulate with break shocks at the rate 
of one per second (moderate strength). Notice the first few contractions. 
After 10 or 12 contractions stimulate with both make and break, continuing 
this until the muscle is entirely fatigued. Group tracing. 
(c) When this occurs, remove the weight, wash the muscle well with 0.7% 
NaCl and allow it to rest for 10 minutes. Replace the load and repeat. 
(&). When again fatigued, increase the strength of the current. Group 
tracing. 
(d) Remove the muscle and cut it into two parts. Press the cut surface of 
one piece on a strip of blue litmus paper, and that of the other piece on 
red litmus. Try this also with a fresh muscle. Explain the results. Source 
of the material responsible for this reaction? How formed? What nor- 
mally becomes of it? Why did this not happen in the present experiment? 
What may this cause? 
From this experiment fully discuss the subject of Work and Irritability. 
Exp. 12.-Automatic Action. Smooth Muscle. 
Apparatus:-Kymograph, time marker, key, stand, clamp holders, heart 
lever, muscle clamp, frog, adrenalin, y2% barium chloride. 
(a) Draw a base line on a drum. Pith a frog; expose the stomach; cut a ring 
from the pyloric end of the stomach about 6 or 8 mm. wide. Insert into 
this ring two wire hooks, attaching one hook to the muscle clamp and the 
other to the writing lever. Place the writing lever on the drum about 
one inch above the base line (very slow speed) ; keep the muscle prepar- 
ation moist. By signal magnet, record time in 5 seconds. 
(&) While the drum is moving very slowly, spontaneous contractions of the 
muscle may take place. Record a number of these. Group tracing. Is 
there any evidence of changes in muscle tone? Length of contraction and 
relaxation period? What property not possessed by the striated muscle 
is demonstrated? 
(c) When a stomach strip is recording its contractions apply a few drops of 
adrenalin (1:10,000). When this has taken effect apply some barium 
chloride. 21 
MANUAL OF PHYSIOLOGY 
Exp. 13-Cilia. 
Apparatus:-Piece of cork, microscope, ether, frog, freezing mixture. 
Pith brain of a frog, place it on its back and cut away the lower jaw. Wash 
the roof of the mouth with 0.7% NaCl. Place a small piece of cork near the 
angle of the jaw and watch the movement of the cork. Determine how long 
it takes to move one cm. 
Moisten the cilia with salt solution having a temperature of 5 degrees, and 
again determine rate. Is the action of the cilia dependent on the central nerv- 
ous system? Place the frog under a beaker and saturate the air under the 
beaker with ether. How are the cilia affected. Blow air over the cilia to re- 
move the ether. Effect ? With scissors remove a very small piece of the ciliated 
epithelium and examine with microscope. What physiological properties do 
the cilia exhibit? Where are cilia found in the body? What is the function 
of the cilia? 
Exp. 14-Reflex Action. 
Apparatus:-Inductorium, key, wire, electrodes, frog-board, frog. 
Pith brain of a frog. Expose both sciatic nerves as follows: 
Place frog, back upward, on frog board, slit open the skin on the thigh a 
little inside the median line. Carefully open the muscles without the use of 
a knife and expose the sciatic nerve. Take great care not to injure the blood 
vessels and do not stretch the nerve. Isolate and place a loose ligature under 
the nerve. Repeat for the other leg. With a weak interrupted current stimu- 
late the left sciatic nerve. Effect? If none, increase strength of current. Now 
place two ligatures close together on the left sciatic and cut in between them. 
Leave a long end on each ligature so that you can handle the nerve by means 
of it. Stimulate the peripheral end. Result? Stimulate the central end. Re- 
sult? How do you explain this? Can you prove this? Proceed to do so. 
What structures are necessary for any reflex action? Which of these have 
you dealt with in this experiment? How could you demonstrate the necessity 
of the other? 23 
MANUAL OF PHYSIOLOGY 
Exp. 15-Reflex Action: Reflex Time. 
Apparatus:-Frog, stand, hook, beakers, i%% HC1, filter paper, 50% acetic 
acid. 
Pith the brain of a frog (make sure of this by the lid reflex). Carefully 
notice the condition of the frog immediately after the pithing; pinch its toes. 
After 5 or 10 minutes pinch the toes again. Why did not the frog respond 
immediately after the operation? What is this condition called? Pass a hook 
through the jaw and suspend the frog. 
(a) What effect has pinching the toes of the foot? Place the long toe in %% 
HC1 and note by watch how many seconds elapse before the foot is with- 
drawn. After the result has been noted bathe the foot thoroughly in tap 
water. Make three determinations and take the average. What is this 
period called? Why is there such a period? 
(&) On the flank place a small piece of filter paper (about 3 or 4 mm. square), 
which has been soaked in 50% acetic acid (shake off most of the acid)'. 
Notice the movement of the animal to remove the irritant. If the frog suc- 
ceeds in removing it, wash the frog in tap water for at least one minute 
and let it rest for 4 minutes. Repeat the above, placing the paper in dif- 
ferent positions (as on the thigh, etc.) and observe the behavior of the 
frog. Wash the frog thoroughly after each application. 
(c) Repeat (5) but while the paper is on the leg, pinch the toes of this leg. 
Result? How can you explain that the "spinal frog" was able to locate 
the pieces of paper? 
(d) Destroy the spinal cord of the frog and repeat (a). What does this teach? 
Make a diagram illustrating this. Could any other parts have been de- 
stroyed and the same results obtained as in destruction of the cord ? 
Exp. 16-Reduction of Nerve Conductivity. 
Apparatus:-Induction coil, key, wire, plug-key, 1% cocaine, 1% novocain, 
%% HC1, frog, stovain. 
(a) Make a muscle-nerve preparation; use as long a nerve as possible. Deter- 
mine the least strength of break induction shocks that will stimulate the 
nerve and cause the muscle to contract. This determines the threshold 
stimulus. Apply 1% cocaine to a short stretch of the nerve and after 5, 10, 
15, etc., minutes again determine the threshold. Discuss your results. 
(&) Pith brain of a frog and determine the length of the reflex time (as in Exp. 
15, a) using i%% IIC1. Make two trials and take average. After each 
determination wash the foot thoroughly with tap water. Now suspend 
one foot in 1% novocain and the other in 1% stovain and at 5 minute 
intervals again determine the reflex time for each foot. Explain the results. 27 
MANUAL OF PHYSIOLOGY 
Exp. 17-Reflexes in the Human Being. 
(a) Tendinous or deep reflexes: 
1. The knee jerk. Sit on the table so that the leg from the knee down hangs 
free. Let another student strike the patellar ligament with the edge of 
a ruler. What is the result? Just previous to the striking of the ligament 
let the subject clench his fist. What effect does this have on the knee 
jerk? Explain. Of what diagnostic value may this reflex be? 
2. The ankle jerk. Let the subject kneel on a chair, the feet hanging over 
the edge of the chair. With a ruler tap the tendon of Achilles and note 
the result. 
3. The inferior maxillary reflex. Let the subject open his mouth. Place 
a lead pencil on the lower teeth; tap this with a ruler and observe the 
raising of the lower jaw. This does not always take place. 
(h) Cutaneous or superficial reflexes. 
4. Corneal reflex. Touch the cornea with a soft object. 
5. Plantar reflex. Scratching the sole of the foot causes contraction of 
the toes. 
(c) Organic reflexes. 
6. Swallowing reflex. Empty the mouth of saliva by swallowing and imme- 
diately swallow again. Are you able to do so? When can you? What 
does this prove? 
7. Pupil reflex. Close the eyes for two minutes; while facing a bright 
light open them and let another student examine; them immediately. 
8. Cilio-spinal reflex. Pinch the skin of the neck and note the dilation of 
the pupil. PART THREE 
Blood 
Exp. 18-Hemolysis or Laking of Blood; Permeability of the Red 
Blood Corpuscle. 
Apparatus:-Microscope, slides, covers, blood, distilled water, 0.7% NaCl 
solution, chloroform, ether, test tubes, m/4 NH4C1, m/2 NaCl, crystals of urea, 
KC1 and dextrose. 
(a) Obtain some defibrinated blood and place a drop of it on a slide and test 
its transparency by trying to read print through it (hold the slide about 
one inch above the paper). Place another small drop on a slide and add 
five drops of distilled water to it; mix. To another drop add five drops 
of physiological salt solution. What difference ipAhe transparency and color 1 
How explained? What property of the salt solution prevents the laking 
of the blood? 
(b) The red blood cells are impermeable to NaCl; consequently, if the cells are 
placed in a hypertonic NaCl solution, they will lose w'ater and become 
crenated. In a hypotonic NaCl solution the cells will absorb water and 
increase in size. Obtain a drop of blood on the point of a pin or knife; 
shake off most of it and make a small smear on a slide; add 3 or 4 drops 
of m/2 NaCl. Cover and study the changes in shape and size of the 
corpuscle. Illustrate your notes by diagrams. 
(c) Repeat (b) using m/4 NaCl solution. 
Repeat (b) using m/16 NaCl solution. Describe and explain the results. 
(e) See whether an m/8 or m/7 NaCl has any effect. If not, why not? Save 
some of this solution for (g) and (h). 
(/) What is the osmotic pressure of m/4 NH4C1 solution compared with that 
of m/4 NaCl? Determine the effect of m/4 NH4C1 on the blood cell. Com- 
pare this with (e) and explain why this difference exists. Be sure to notice 
the immediate and the final result. Explain difference. 
(g) To 3 or 4 drops of the NaCl solution in (e) that had no visible effect on 
the cells, add a few urea crystals. How does this affect the osmotic pressure 
of the solution? With this solution repeat (b) and explain results. 
(/t) Repeat (g) but use dextrose instead of urea. Also try KC1. What does 
this prove? 
(t) Hemolysis by chloroform, etc. Place a drop of blood in a clean dry test 
tube and add three drops of chloroform. Gently agitate for a little while. 
Pour contents on a slide and quickly note transparency. Repeat with ether. 
How do these reagents bring about this result? What property do these 
reagents have in common? What are reagents producing this result called? 
29 33 
MANUAL OF PHYSIOLOGY 
Exp. 19-To Determine the Osmotic Pressure at Which the Hemoglobin 
is Driven from the Red Blood Corpuscle. 
Apparatus:-m/4 NaCl solution, defibrinated blood, test tubes, graduated 
pipette, distilled water. 
Take some m/4 NaCl solution; by diluting it with distilled water make about 
10 c.c. of the following NaCl solutions: m/6, m/8, m/9, m/9.5, m/10, m/10.5, 
m/11, m/12. In the 9th test tube place 10 c.c. of pure water. Make these dilu- 
tions carefully and explain fully in your notes how you made them. 
To each of the test tubes, add 5 drops of blood and shake the test tubes gently 
but thoroughly. Allow the test tubes to stand for y2 hour (don't disturb) ; 
note results. Why this difference in the supernatent fluid? Tn what concen- 
tration do the corpuscles begin to lose their hemoglobin ? 
Exp. 20-The Specific Gravity of Blood. 
Apparatus:-Blood lancet, absorbent cotton, urinometer, chloroform-benzol 
mixture, chloroform, benzol, alcohol. 
To obtain blood proceed as follows: 
Clean the palmar surface of the finger tip (or the lobe of the ear) with 
alcohol. Sterilize the lancet by means of alcohol. Puncture the skin with a 
quick and firm stab; the long axis of the cut must be diagonally across the finger 
top. If necessary press gently to start the flow; after this the blood must flow 
freely. Do not use blood squeezed out. 
This experiment must be worked as quickly as possible. Put the mixture 
of chloroform and benzol of about 1058 sp.gr. (from large bottle) into a glass 
cylinder. Be sure this is clean and dry; care must be taken to get no water in 
the reagents. Obtain a drop of blood as directed and transfer it to the mixture. 
If it sinks add chloroform drop by drop; if it rises, add benzol: after each 
addition of chloroform or benzol place your hand tightly over the cylinder and 
gently invert the tube three or four times to insure thorough mixing. Repeat*1 
this process till the drop remains suspended wherever it is placed. When this 
occurs, immediately (why?) take the sp. gr. of the mixture. Give reasons for 
procedure? What is the normal sp. gr.? How does this compare with the sp. gr. 
of milk, lymph or urine? What causes the high sp. gr. of blood? What is in- 
dicated if the sp. gr. is low? Make a sketch of the apparatus. 
N. B.-At the close of the experiment filter the mixture and restore it to the 
mixture bottle. Do not waste any of flic reagents. Do not let the bottles remain 
uncorked. 
1.040=40 per cent lib. 
1.050=65 per cent Hb. 
1.055=75 per cent Hb. 
1.060=9.5 per cent Hb. 35 
MANUAL OF PHYSIOLOGY 
Exp. 21-Determination of the Number of Red Blood Corpuscles. 
Apparatus:-Hemocytometer, absorbent cotton, 3% NaCl, microscope, lancet, 
alcohol-ether. 
1. Obtain a large drop of blood as directed in Exp. 20. 
2. Take the large tube and suck up the blood till it reaches the mark 1. Dry 
the tip of the pipette. If the 1 mark should be passed, touch the point of pipette 
with filter paper until the column of blood stands at I. Immediately suck up 
3% NaCl solution till the mixture reaches the 101 mark. Rotate the pipette 
while filling it. Make these measurements very carefully. If the 101 mark is 
passed, the tube must be cleaned as directed below, and the work started afresh. 
3. Close the end of pipette with the finger and shake the glass bead in the bulb 
of the tube, thoroughly mixing the blood and the solution. How many times 
has the blood been diluted? 
4. Blow out 5 or 6 drops. Why? Wipe the end of the pipette and let a small 
drop form at the end. 
5. Touch this to the ruled disk and allow a small drop to flow upon the disk 
of the counting slide; cover quickly, press the edges of the cover down gently. 
Do not slide the cover over the drop. No blood should run over into the moat. 
Let the corpuscles settle for 4 or 5 min. If blood runs into the moat, clean the 
slide as directed below and use a smaller drop. 
6. Place it on the microscope stage and notice the lines ruled on the glass 
(high power). Be very careful in focusing. Count the number of RBC in at 
least 20 cells and take the average. The size of the cell is 1/20x1/20x1/10 
millimeter. How many RBC in one cu. inm.? (Remember the blood has been 
diluted.) What per cent is this of the normal? 
7. Sketch the apparatus. 
Caution:-Never let the bloud coagulate in the tube. If the blood does not 
form a solid column in the tube, the tube has not been properly filled and you 
must blow the blood out immediately and clean the tube first with distilled water 
till all the blood has been removed, then with alcohol and lastly with ether. Let 
this last run out and pass compressed air through the tube until it is dry. If 
thoroughly dry, the glass bead will not stick to the sides of the tube. In case 
the blood can not be removed by means of distilled water, use water solution of 
hydrogen peroxide; if this fails, call the assistant. Clean the slide and cover 
with distilled water and absorbent cotton; never with alcohol or ether. Do not 
scratch the slide and keep it out of direct sunlight. 37 
MANUAL OF PHYSIOLOGY 
Exp. 22-Determination of White Blood Corpuscles. 
Apparatus:-Same as in Exp. 21. 
Follow the directions in Exp. 21 but use the other tube, marked 1 and 11, and 
use the methyl-violet diluting fluid. This colors the white cells only. Hold the 
tube horizontally. Count the white cells in 60 squares. Average? Number 
per cu. mm.? What is the normal number? Ratio of red to white corpuscles? 
Exp. 23-Sahli's Hemoglobinometer. 
Apparatus:-Sahli's hemoglobinometer, lancet, cotton, n/10 HC1. 
Note the following parts of the apparatus: 
1. A capillary measuring tube with a mouthpiece. 
2. The standard color tube. 
hemoglobin stated? What variations in the amount of Hb? 
Fill the mixing tube up to about the 10 mark with n/10 HC1. Obtain a 
good sized drop of blood: suck the blood up into the capillary tube to the 20 
cu. mm. mark. Blow the blood into the acid in the mixing tube; suck up a 
little of the acid into the tube and return to the mixture. In this manner the 
capillary tube is rinsed and the acid and blood are thoroughly mixed. 
After about a minute the mixture will be dark brown and clear. Add a small 
quantity of water, shake and compare the color with the standard by holding 
the tubes between your eye and the light. If necessary add more water and 
again shake well. Towards the end the water must be added drop by drop and 
after each addition the tube must he shaken and its color compared with the 
standard. When the two tubes have the same color, read the scale on the side 
of the tube. Make at least two determinations for the same (Why?) person's 
blood. What is the normal amount of hemoglobin? How is the amount of 
hemogoblin stated? What variations in the amount of Hb? 
Exp. 24-Blood Quotient. 
From experiment 21 and 23 calculate the blood quotient according to follow- 
ing formula: Per cent Hb divided by per cent number RBC equals the blood 
quotient. What is meant by the blood quotient? Object of determining it? 39 
MANUAL OF PHYSIOLOGY 
Exp. 25-Hemoglobin and its Derivatives. 
Apparatus:-Test tubes, defibrinated blood, hydrogen peroxide, ammonium 
sulphide, sodium nitrite, guinea-pig, Canada balsam, amyl alcohol, slide and 
coverslip, microscope. 
(a) In a test tube place about 10 c. c. of defibrinated blood. Shake it well with 
air. Color? What kind of blood is this? What compound is formed? 
Divide this blood into two equal parts. 
(&) To one part of (a) add a drop or two of ammonium sulphide and gently 
mix. Compare color with (a). Why different? What kind of blood is 
formed in (b) ? What is the color due to? 
(c) To (b) add a few drops of hydrogen peroxide; shake tube. Account for 
change in color. Where in our body does (a) occur? Where does the 
change illustrated in (b) take place? What brings about this change? 
What is its object? What valuable property of Hb is illustrated in (a), 
(b), and (c) ? 
(d) Slowly pass CO (illuminating gas) through about 10 c. c. of defibrinated 
blood to which you have added one or two c. c. of amyl alcohol (to prevent 
foaming). After 10 minutes compare its color with tube (a). To one- 
half of this blood add a few drops of ammonium sulphide. Result? Com- 
pare with (b). Why different? What is the result of t^he inhalation of 
CO? Why? 
(e) Dilute one c. c. of defibrinated blood with 10 c. c. water. Divide into two 
parts. To the one part add a few drops of sodium nitrite (or amyl nitrite). 
Observe the change in color. The compound formed is methemoglobin. 
What is said to be the important difference between this and oxyhemo- 
globin? What is one of the results if the change illustrated in this experi- 
ment takes place in the animal body ? Why ? 
(/) On a slide place a drop of guinea-pig's blood and on this a drop of Canada 
balsam. Cover and examine for crystals of Hb. Draw. 43 
MANUAL OF PHYSIOLOGY 
Exp, 26-Guaiacum Test for Blood. 
Apparatus:-Hydrogen peroxide, guaiacum tincture, potato, blood, graduate, 
test tubes, burner. 
(a) Place two or three drops of defibrinated blood in a test tube. Add 2 drops 
of guaiacum and a little hydrogen peroxide. The blood decomposes the 
II2O2 and the guaiacum is oxidized, giving rise to a blue color. Next drop 
a few drops of guaiacum and H2O2 on a piece of potato (immediately be- 
neath the skin). Boil a small piece of potato for 3 or 4 minutes and make 
the test. Try the same with blood. 
In the potato and other substances this action is brought about by 
enzymes called oxydases. These enzymes also exist in the blood, but in 
addition to this the Hb (or its iron-containing derivatives) has the power 
to split up the peroxide. In how far is this a good test for blood? How 
can it be rendered more accurate? 
(6) Thoroughly clean 6 test tubes. Dilute one volume of blood with 800 parts 
water (1 drop of blood plus 40 c. c. water), and from this make dilutions 
■with 1600, 3200, 9600, and 28,800 parts water. Place one c. c. of each 
in one of the test tubes and in the sixth tube place water. To each add 
a few drops of benzidin dissolved in glacial acetic acid and a drop or two 
of hydrogen peroxide. Discuss the value of this test. 
Exp. 27-Hemin or Teichmann's Crystals. 
Apparatus:-Microscope, slides, covers, dried blood, glacial acetic acid, Bun- 
sen burner. 
Place a few small scrapings of dried blood on a slide or carefully evaporate 
some fresh blood to dryness. As this is fresh blood no NaCl needs to be added. 
Triturate. Add 2 or 3 drops of glacial acetic acid and cover with coverslip. 
Warm one end of this slide carefully over a small flame till bubbles begin to 
appear. Take out of flame, add another drop of acid and warm again. When 
cool examine with microscope, high power. Draw some of the crystals. Color? 
Give three reasons why this is a good test for blood. What disadvantage? 45 
MANUAL OF PHYSIOLOGY 
Exp. 28-Defibrinating the Blood; Fibrin; Serum. 
Apparatus:-Test tubes, artery cannula, artery clips, wood for whipping 
blood, dog, 4 inches of rubber tubing, slides, covers, microscope, 25% acetic 
acid. 
(a) To a dog administer by means of a stomach tube 0.25 gram chloretone per 
kilogram of body weight. When the animal is under the influence of the 
drug, place it on a dog-board. If necessary cut the hair from the region 
over the trachea. Make a longitudinal incision through the skin and fascia 
over the trachea. By blunt dissection separate the mesial borders of the 
sternohyoid muscles, thereby exposing the trachea. Along side of and 
a little dorsal to it you will find the carotid artery. Feel for the pulsa- 
tion. Expose a stretch of this artery and clean it carefully from all fascia. 
Place a ligature at the distal end of this part and an artery clip at the 
proximal end. Between these two make a V-shaped incision with scissors 
(point towards the heart) and insert a cannula, securing it in the artery 
by means of a ligature. Open the artery clip, catching some blood in a 
dish. Let one of the students immediately whip this blood with a roughened 
piece of wood. The fibrin collects on the wood; retain both the liquid 
and the fibrin. 
(&) Place a drop of blood issuing from the cannula on a slide and place this 
in a moist chamber. After a few minutes examine this with the microscope 
(low power) for threads of fibrin and the clumping of the corpuscles. Con- 
tinue to observe it for at least 15 minutes. 
(c) Let a little blood from the artery flow into a test tube containing some 
hirudin. Set it aside and note the result. 
(d) Catch about 5 c.c. of blood in each of three test tubes:-(a) a vaselined 
tube, (b) a tube containing a pinch of sand, and (c) an untreated tube. 
Record the time the blood was placed in these tubes. By gently tilting the 
tubes at intervals of one or one half minutes, determine the coagulation 
time for these three samples of blood. Explain any difference. Let tube 
(c) stand for 24 hours and describe its appearance. What is the fluid 
formed called? 
(e) Pour some of the defibrinated blood obtained in (a) either into a test tube 
and let it stand to settle for a least 24 hours, or into centrifuge tubes and 
centrifuge until a clear serum is obtained. Note the relative amount of 
corpuscles and serum. 
(f) By means of a pipette carefully remove about 5 c.c. of the serum without 
disturbing the red corpuscles. To the serum add 2 drops of 25% acetic 
acid and coagulate the protein by boiling. What proteins are found in 
serum ? In blood ? 
(g) Take a small piece of the fibrin obtained in (a) and wash it thoroughly 
in water, kneading it meanwhile. Describe the characteristics of fibrin. 
Solubility in water? Place a shred of fibrin in a little water and make 
Millon test. To what class of bodies does fibrin belong? Its origin? Its 
use? 49 
MANUAL OF PHYSIOLOGY 
Exp. 29-Preventing Coagulation. 
Apparatus:-Oxalate blood, Salt-plasma, 2% CaCL, test tubes, ice, water 
bath, thermometer. 
(a) The instructor has caught some fresh blood in a dish containing a little 
sodium oxalate solution. Obtain 15 c.c. of this oxalate blood. Condition.' 
To 5 c.c. add 7 drops of 2% CaCL and to another 5 c.c. add 20 dro^s. 
Place in the water bath at 40 deg. C. and by your watch note in low 
many seconds or minutes clotting begins. When the blood is well cbtted 
the clot adheres closely to the walls of the tube. Let the tube stand for at 
least 24 hours and notice a solid mass suspended in a liquid. What are 
these two parts called? Color of the liquid? What part does calcium 
play in coagulation? Why is oxalate blood liquid? Place another 5 cc. 
of oxalate blood on ice and when it has a temperature of 5 degrees C. add 
the 7 drops of CaCL and determine length of coagulation time. 
(6) To another quantity of fresh blood an equal volume of half saturated 
NaoS04 solution has been added. This has been allowed to stand for some 
time and the corpuscles have settled. Notice the more or less clear plasma. 
Dilute about 5 c.c. of this salt-plasma with 25 c.c. distilled water. Place 
half of this diluted salt-plasma in a test tube containing a piece of blood 
clot or a few drops of serum and set it in warm water bath. Also place 
the remainder in the bath and note length of coagulation time. Why is 
this shorter in the first tube? How could you differentiate plasma from 
serum? PART FOUR 
Circulation 
Exp. 30-Anatomy of the Mammalian Heart. 
(a) Note the following structures:- 
1. The right and left auricles. 
2. The right and left ventricles. 
3. The aorta and the pulmonary artery. 
4. The superior and inferior vena cava and the fotr pulmonary veins. 
5. The coronary vessels. 
(6) Cut open the two auricles and note:- 
1. Thickness of auricular walls. 
2. Absence of valves at mouth of veins 
3. The septum between the two auricles. 
4. The aurieulo-ventricular orifice. 
(c) Make a series of cross sections of the ventricles, beginning at the apex and 
working toward the base until both cavities and the aurieulo-ventricular 
valves are brought into view. Note:- 
1. Thickness of walls of the two ventricles. Why is this difference neces- 
sary? 
2. The columnae carneae. The chordae tendineae and their attachment to 
the valves. 
3. The bicuspid and tricuspid valves. 
4. The openings into the aorta and into the pulmonary artery. 
5. The semilunar valves. 
(d) Securely tie a funnel into the aorta or pulmonary artery and pour water 
into it. Notice the closure of the valves, preventing the escape of the 
water into the ventricles. From below push the valves open. 
(e) Slit open the pulmonary artery and the aorta so as to expose the valves. 
Note: - 
1. The number and shape of the segments. 
2. The sinuses of Valsalvt Their function? 
3. The mouth of the coronary artery. 
4. Compare the thickness and elasticity of the walls of the arteries and 
veins. Why is this difference of great consequence? 
51 53 
MANUAL OF PHYSIOLOGY 
Exp. 31-Anatomy of Frog's Heart. 
Apparatus:-Frog board, frog. 
Pith the brain of a frog. Fasten the frog to frog board, back down. Cut 
through the skin over the thorax and then cut through the chest wall, thereby 
exposing the heart with as little loss of blood as possible. Keep the heart moist 
with Ringer's solution. Observe and describe:- 
(a) The pericardium. Notice its thinness, strength and inelasticity. What are 
its functions? Slit it open. 
(6) The two auricles. 
(c) One ventricle. Compare its wall with that of auricles. Notice the auriculo- 
ventricular groove. 
(d) Bulbus arteriosus springing from the ventricle and dividing into two aortae. 
(e) On dorsal side is the sinus venosus emptying into the right auricle. To 
see this tilt the apex of the ventricle upward and forward. A white crescent- 
like structure will be seen; this separates the auricles from the sinus. 
(/) The two superior and one inferior venae cavae emptying into the sinus. 
Draw a diagrammatic sketch of the frog's heart. 55 
MANUAL OF PHYSIOLOGY 
(e) SB. closed; obtain about 100 mm. Hg. pressure. 
1. Notice the pulse; its characteristics, such as frequency, hard or soft, 
slow (pulsus tardus) or quick (pulsus celer). A quick pulse is not 
necessarily a frequent pulse, but one that reaches its maximum quickly 
-one might say a sharp, kicking pulse. What is the pulse ? 
2. Now partially open SB. so as to obtain with the same rate of pump, a 
pressure of about 30 mm., and repeat (1). Can you account for the 
difference ? 
3. Close SB. Pump so as to have 30 mm. pressure and repeat (1). Is 
there a pulse in the veins in (1), (2) or (3) ? Under what conditions 
in the living body is there a venous pulse? 
(/) Having SB. closed, obtain about 100 mm. Hg. pressure. Slow the stroke to 
about 20 per minute, and notice the valves. By the gush of water from 
beneath the rubber flap covering the hole in the metal tube you can judge 
of the opening of the valve. With respect to the systole and diastole, deter- 
mine the opening and closing of both valves. Do they both open at the 
same time? Reason? As to their closing? 
(g) With SB. closed, obtain fairly high Art. P. Maintaining the same number 
of strokes of even force, gradually open the SB. and note: 
1. Effect on Art. P. ? Is the rise synchronous with the systole of the pump ? 
Why? 
2. What condition of the vascular system does this represent? The stimu- 
lation of what nerve has this effect? 57 
MANUAL OF PHYSIOLOGY 
Exp. 33-Graphic Record of Heart-Beat. 
Apparatus:-Frog board, kymograph, frog, heart lever, stand, clamps, signal 
magnet, wire, key, a hook, tuning fork, thread. 
(a) Pith the brain of a frog; inject a couple of drops of curare into the dorsal 
lymph sac. When the curare has taken effect, place frog on frog board 
and expose the heart and slit open the pericardium with as little loss of 
blood as possible. Pass a fine hook (bent pin) through the tip of apex so 
as not to puncture the ventricle, and by means of thread connect this hook 
with the short arm of the heart lever. When the heart contracts, the 
auricle first pulls the lever up a slight distance, then the ventricle contrac- 
tion raises it still further. It may be possible to detect the contraction 
of the sinus venosus. The lever must be balanced delicately by means of 
counterweight, so that the heart is stretched to a very slight extent. Keep 
the heart moist. Let the writing point come in contact with the drum so 
as to make a mark when the lever is raised and lowered, but there must 
not be much friction. Place the point of the signal magnet (recording sec- 
onds) directly below the point of the heart lever. Record a stretch of heart 
beat (about 2 or 3 inches). Individual tracing. Label: Graphic Record 
of Frog's Heart. 
(&) Use same speed of kymograph. Cool some Ringer solution to 5°C and by 
means of a pipette cool the heart. When you have reason to believe the 
heart is well cooled take a tracing (Group tracing). Next use Ringer solu« 
tion at 12°C and then at 25°C. Compare the rates at the various tem- 
peratures. 
(c) Fast kymograph. Instead of the signal magnet use the tuning fork. Ob- 
tain a tracing of two heart beats with the tuning fork tracing. Individual 
tracing; same legend as above. When the tracing is dry, draw perpen- 
diculars from the characteristic points of the heart tracing to the tuning 
fork tracing. This will enable you to calculate the length of the various 
phases of the cardiac cycle. Calculate:- 
1. Rate of heart beat per minute. 
2. Tn hundredths of a second: 
Auricular systole 
Auricular diastole 
Total 
Ventricular systole 
Ventricular diastole 
Total 
3. Ventricle works per cent of the time. 
Ventricle rests per cent of the time. 61 
MANUAL OF PHYSIOLOGY 
Exp. 34-Properties of the Heart Muscle. Effect of Previous Stimulation; 
Stair-case Phenomenon. 
Apparatus:-Frog board, frog, thread, aneurism needle, induction coil, wire, 
key, electrodes. 
To study certain properties of the cardiac muscle, it is often necessary to 
have a quiescent heart. This can be obtained by means of the First ligature 
of Stannius. 
(a) Pith brain and cord of a frog; expose heart and remove pericardium from 
heart and aortae. Pass a ligature beneath the bulbus arteriosus and bring 
it forward and tie it between the auricles and the sinus venosus, the sinus 
will continue to beat, but the rest of the heart will be quiet. If these re- 
sults are not obtained apply another ligature. 
(&) Stimulate the ventricle with a pin or a single induction shock. What prop- 
erties of the ventricular muscle are here demonstrated? 
The cessation of beat in the auricles and ventricle by the first Stannius 
ligature is generally attributed to the stimulation of the inhibitory mechan- 
ism in the sinus. Others hold that the ligature merely destroys the con- 
ductivity and the impulse originating in the sinus cannot pass down the 
rest of the heart. 
(c) Set up recording apparatus as in Exp. 33 (a). Slow drum. Stimulate 
the quiet heart with a medium strength break induction shock (short cir- 
cuit the make). After about 5 seconds repeat and so on until you have 
recorded about 10 contractions, using the same strength of break induc- 
tion shocks. Discuss your results. Group tracing. Label the tracing' 
"Staircase Phenomenon of Heart." 63 
MANUAL OF PHYSIOLOGY 
Exp. 35-Properties of Heart Muscle. "All or Nothing.'' 
Apparatus:-As in Exp. 34. 
If possible use the frog of Exp. 34, otherwise repeat Exp. 34 (a). Record 
by suspension method. Stimulate the quiet ventricle with the weakest possible 
single break induction shock (short circuit the make). If a contraction occurs, 
record it on the stationary drum; after each contraction move the drum about 
1/2 inch. After one minute (not sooner) move secondary coil 1 cm. closer to 
(the primary and repeat the above (use break shocks only). Record contrac- 
tion (if any) as before. After another minute rest repeat with a little stronger 
current. Continue this until full strength of current is used. Under each 
line of the tracing state distance between primary and secondary coils. How 
do the results obtained compare with those obtained with the skeletal muscle 
(Exp. 9) ? Why this difference? Why is it necessary to wait about one minute 
between stimulations? Group tracing. Label your tracing "All or nothing 
of frog's heart." 
Exp. 36-Properties of Heart Muscle. Extra-Systole. Compensatory Pause. 
Refractory Period. 
Apparatus:-Key, induction coil, kymograph, frog board, stand, clamps, elec- 
trodes, signal magnet. 
Place the signal magnet in the primary circuit so as to indicate point of 
stimulation. The point of the signal must be directly above or below the point 
of the heart lever; this is very essential to the success of the experiment. Ex- 
pose the heart of a pithed frog and obtain a tracing, as in Exp. 33, on a 
medium speed drum. Stimulate the ventricle with a single break shock only, 
short circuiting the make shock. Note the resulting extra-contraction (if any) 
and the phase of the heart when the stimulation was thrown in. Repeat this 
stimulating about five or six times per minute. Some of the stimuli will fall 
during the svstole, others during diastole. Note effect. When does the heart 
respond to the stimulation and when does it not? What is this last period 
called? When an extra-contraction takes place, notice the following period 
of rest; how does it compare with the normal? What is this called? 
Group tracing. Label your tracing "Extra-systole, compensatory pause and 
refractory period." 67 
MANUAL OF PHYSIOLOGY 
Exp. 37-Transmission of Cardiac Excitation. The Block. 
Apparatus: Frog board, Gaskell's clamp, a large frog. 
(a) Notice the orderly sequence in the beating heart. Does the ventricle beat 
as often as the auricle? Which is in systole first? The impulse therefore 
travels in what direction? Notice the pause between the auricular and 
the ventricular systole. What does this pause indicate as to the tissue unit- 
ing the auricle and the ventricle? How can we explain the fact that the 
impulse begins in the sinus? 
(&) Now place Gaskell's clamp at the auriculo-ventricular groove. Turn the 
screw so that the rubber edge just touches the heart. Count the auricular 
and the ventricular contractions. If normal, turn the screw just a trifle 
more and again observe the effect. Continue this process very slowly until 
there is a difference in the auricular and ventricular rate of beat. Record 
four readings of the rates of the two cavities with gradually increasing' 
pressure. 
Note:-Let one student count the auricular and another the ventricular 
beat at the same time. Explanation? What condition is supposed to pro- 
duce the same result in man? 
If you can succeed in stopping the ventricle altogether, touch the 
quiescent ventricle with the point of a knife. Result? What property 
does the ventricle possess? 
(c) Release the clamp and place it on the ventricle midway between base and 
apex, using enough pressure to cause the apex to be quiescent when the 
clamp is removed. When this has been obtained close the aorta with for- 
ceps and observe the apex. Explain the results. 
(d) Pith a frog. Expose the heart and make 4 or 5 interdigitating sections 
across the ventricle. Note the contraction of the strips. What does this 
demonstrate? Cut the ventricle from the auricle. Result? Explanation? 
Stimulate the apex with a single induction shock. In what direction did 
the impulse travel? 69 
MANUAL OF PHYSIOLOGY 
Exp. 38-Influence of Temperature on Heart. 
Apparatus:-Frog, freezing mixture, glass dish, test tubes, thermometer. 
Count the rate per minute of the exposed frog heart. Excise the heart 
(See Exp. 32, h). Place the heart in a dish filled with Ringer's solution. Does 
it continue to beat? What does this prove as to the relation between the heart 
beat and the central nervous system? Take the temperature of the solution 
and determine the rate of the beat. Now transfer the heart to a test tube con- 
taining about 5 c.c. of Ringer's solution, having a temperature of about zero. 
When the heart has acquired this temperature, determine rate of heart. As 
the tube stands on the desk, the temperature will gradually rise. Determine 
the rate for every three degrees rise. When the room temperature is reached, 
carefully add warm Ringer's solution and proceed in the same manner till 35 
degrees C has been reached. Besides the changes in the rate of the beat, are 
there any other changes such as strength and rapidity of contraction and relax- 
ation ; rhythm ? As the heart beat is increased, is the shortening of the diastole 
the same as that of the systole? 
Plot a curve on cross-section paper, using the degrees as abscissae and the 
rates as ordinates. 
Exp. 39-Action of Chloroform and Ether. 
Apparatus:-Chloroform, ether, graduated pipette, two frogs, test tubes. 
Excise the hearts of two small frogs of the same size; be sure to include the 
sinus venosus. Place in a dish with Ringer's solution, and by watch obtain 
rate per minute. After one or two minutes transfer the one to a test tube contain- 
ing 15 c.c. Ringer's solution (accurately measured) and 3 drops of chloroform; 
cork. Transfer the second heart to 15 c.c. Ringer's solution plus 3 drops of 
ether; cork. Obtain rate after 1, 2, 4, 7, 10, 15, 20 and 25 minutes and note 
exactly how long both hearts continue beating. Tn what phase do they stop? 
Discuss the relative potency of these two drugs. 
On co-ordinate paper construct two curves, in colors, showing the rate of 
beat before and after the action of the drugs. 73 
MANUAL OF PHYSIOLOGY 
Exp. 40-Cardiogram; Cardiac Impulse. 
Apparatus:-Kymograph, cardiograph, time marker, wire, key, tambour. 
(a) Locate the cardiac impulse of a fellow student. Place the button of the 
cardiograph over the cardiac impulse. The cardiograph is connected by 
means of a tube ■with the recording tambour. In this tube is a T-tube 
which must be closed when everything is in readiness for a tracing. Let 
the pen of the tambour write on a medium speed drum. Also record time 
in seconds. Group tracing. Study the tracing obtained, consulting text- 
books on the subject. 
(&) Note the changes in the position and strength of the apex beat as the sub- 
ject lies on his left or right side and as he stands. What do you recall, 
about its position in pathological conditions? What about the force of 
the apex beat? Its origin? 
Exp. 41-Heart Sounds. 
Apparatus:-Stethoscope. 
This experiment is to be performed in a quiet room. Locate cardiac impulse 
in a fellow student. Apply the stethoscope to this point and note the two cardiac 
sounds. Note differences in pitch, loudness and duration of these sounds. Feel 
of the radial pulse and note synchronism with the first or second sound. Observe 
the pause following the first sound and compare with that following the second 
sound. While listening to the sounds feel with the finger for the apex beat and 
note when this occurs with respect to the sounds. What are the causes of the 
two heart sounds? 
Place stethoscope to the second right costal cartilage; here the second sound 
is best heard. Why ? The sound caused by the pulmonary valve is best heard 
over the second left costal cartilage. 75 
MANUAL OF PHYSIOLOGY 
Exp. 42-The Pulse. 
This experiment is to be made at home. Count the rate of the radial pulse 
under the following conditions: 
After lying down for 15 minutes 
After sitting for 5 minutes 
After standing for 5 minutes 
Immediately after violent exercise 
During prolonged and deep inspiration 
During prolonged and deep expiration 
Before rising in the morning 
15 minutes after rising 
At noon 
Before principal meal 
10 or 15 minutes after meal 
6 P. M 
Just before retiring 
On cross-section paper plot these variations. 
Exp. 43-The Pulse Tracing. The Sphygmograph. 
Apparatus:-Sphygmograph, kymograph, paper. 
Cut 5 or 6 papers to fit the sphygmograph; smoke them (or use the kymo- 
graph.) 
Adjust the button of the sphymograph over the radial artery with sufficient 
pressure to flatten the artery. Notice the small wheel connected with an ec- 
centric by which the pressure can be altered. Diminish the pressure until a 
maximum excursion of the pen is obtained; now let the paper run through. 
Observe the primary and dicrotic wave and state probable cause of each. Is 
the tracing normal? In what conditions is the dicrotic wave small? Group 
tracing. 77 
MANUAL OF PHYSIOLOGY 
Exp. 44-Blood Pressure in Man. The Sphygmomanometer. 
Apparatus:-The sphygmomanometer, stethoscope. 
(a) This experiment is to be performed in a quiet room. Fasten the rubber 
bag to the upper arm by means of the strip of cloth. Place the bell of 
the stethoscope over the bifurcation of the brachial into the radial and 
ulnar arteries (just below the bend of the elbow). Notice that no sound 
is heard. Inflate the rubber bag; if the pressure is high enough, no sound 
will be heard. Now, by means of the valve, very gradually reduce the 
pressure. At a certain point a sound is heard; this indicates that the 
blood pressure is capable of overcoming the outside pressure, and that 
blood is being sent through the artery. The highest pressure at which 
the sound can be heard is the systolic pressure. Next reduce the pressure 
still more; the lowest pressure at which the sound can still be heard is the 
diastolic pressure. To avoid congestion the pressure should not be left 
very long on the arm. Record three systolic and three diastolic pressures 
and take average. 
(&) Calculate the pulse pressure and the mean pressure. 
(c) Influence of position of body. Take systolic pressure while standing and 
sitting. Next lie down on the table and determine it after 5 minutes. Why 
does this difference exist? 
(d) Determine the effect of amyl nitrite on blood pressure (use one pearl). 
Explain. 
Systolic 
Pressure 
Diastolic 
Pressure 
Pulse 
Pressure 
Mean 
Pressure 
Reclining 
Sitting 
Standing 
After inhaling 
Amyl nitrite 
Exp. 45-Venous Blood Pressure. 
Hold your hand down and note the veins on the back of the hand. Raise 
the hand high above your head and notice the collapsing of the veins. Why? 
Now place your hand at the level of your heart and then slowly raise the 
hand until a height is reached where they collapse. Measure the distance (in 
millimeters) between these two points. What does this indicate? 79 
MANUAL OF PHYSIOLOGY 
Exp. 46-Capillary Circulation. 
Apparatus:-Web-board, microscope, pins, frog, 0.7% NaCl. 
(a) Pith the brain of a frog. Inject into the dorsal lymph sac a couple of 
drops of a 1% curare solution. Object? Fasten the frog to the web- 
board. In this experiment either the tongue or the web may be used. The 
tongue of the frog is fastened at the anterior end only. Pull the tongue 
forward and pin the bifurcated end over the hole at the end of the board. 
Do not stretch the tongue or web too tightly as this may stop circulation; 
if this should happen, release the organ somewhat. Keep it moist con- 
tinually with salt solution. Examine with low power of microscope and 
determine the following:- 
(&) Find a small artery. How can you tell the difference between this and 
a vein (direction of flow) ? 
(c) Nature of the flow in an artery? Why? 
(d) Observe a small vein. Character of flow. Why? 
(e) Compare velocity of flow in capillaries with that in arteries or veins. Ex- 
plain difference. 
(f) View with high power. If necessary place a small piece of coverslip on the 
tongue. If the flow of the blood is too fast, apply gentle pressure at the 
end of the tongue. Find a capillary and notice its width as compared 
with the diameter of the red blood corpuscle (R. B. C.) 
(g) Shape of R. B. C. Of the nucleus. 
(h) Have you found evidence of the elasticity of R. B. C.? 
(i) Character of the flow in a capillary? Why? 
(j) Observe with high power a slightly larger vessel. Can you distinguish bej 
tween the red and white B. C. ? 
(k) Do you notice any difference in the location of the red and white B. C.? 
Why? Do they move equally fast? Reason? 
(Z) Color of the peripheral plasma free from R. B. C. ? 
(m) Notice the sudden appearance and disappearance of capillaries. Explain. 83 
MANUAL OF PHYSIOLOGY 
Exp. 47-Hemodynamics. 
Apparatus:-Artificial circulation scheme, distilled water. 
In this system the pump represents the left ventricle; the two valves, the 
mitral and aortic valve respectively; the resistance of the wood, the capillaries; 
the tubes between the pump and the resistance, the arteries; those on the distal 
side of the resistance, the veins. The opening of the side branch substitutes 
a wide branch for the narrow one; this is equivalent to a dilation of the ves- 
sels. The mercury manometers measure the pressure; the one, the arterial 
pressure (Art. P) ; the other, the venous pressure (Ven. P). 
Fill the reservoir with distilled water and pump the apparatus full, adding 
more water as needed; be careful not to force the mercury out of the arterial 
manometer. Make a diagram of the apparatus, naming the various parts. 
(a) With side branch (SB.) open work the pump 10 strokes in % minute. 
1. When does most of the water escape, during or between the strokes? 
Why? 
2. Is the venous outflow continuous or intermittent? 
3. Note arterial pressure (Art. P). Record its height during systole and 
diastole in mm. of Hg. What is the average pressure? 
4. Gradually increase the number of strokes. How are 1, 2 and 3 affected? 
(&) Close SB. Pump about 60 per minute. 
1. Nature of outflow from the veins? Why? 
2. Arterial P. Constant? Nature and extent of variation as compared 
with (a) 3? 
3. Compare Ven. and Art. pressure. Why these differences? 
4. Feel for pulse in artery and vein. 
5. Feel of the arteries and notice fullness and hardness. 
(c) Open SB. Pump 20 per minute. 
1. Nature of venous outflow? 
2. How could a uniform venous flow be obtained without closing SB. ? 
Try it. Would this be practicable in the living animal? 
3. From (b) and (c), what two factors are necessary to produce a con- 
stant venous flow? What advantage in a constant flow? 
(d) While a good pressure is up and SB. closed, cease pumping. This cor- 
responds to vagus inhibition. Determine the following: 
1. Does Art. P. fall to zero immediately? Why? 
2. Notice and describe venous outflow. Give reason for this continued flow. 
3. What other benefit of elastic arteries is here suggested? 85 
MANUAL OF PHYSIOLOGY 
(e) SB. closed; obtain about 100 mm. Hg. pressure. 
1. Notice the pulse; its characteristics, such as frequency, hard or soft, 
slow (pulsus tardus) or quick (pulsus celer). A quick pulse is not 
necessarily a frequent pulse, but one that reaches its maximum quickly 
-one might say a sharp, kicking pulse. What is the pulse ? 
2. Now partially open SB. so as to obtain with the same rate of pump, a 
pressure of about 30 mm., and repeat (1). Can you account for the 
difference ? 
3. Close SB. Pump so as to have 30 mm. pressure and repeat (1). Is 
there a pulse in the veins in (1), (2) or (3) ? Under what conditions 
in the living body is there a venous pulse? 
(/) Having SB. closed, obtain about 100 mm. Hg. pressure. Slow the stroke to 
about 20 per minute, and notice the valves. By the gush of water from 
beneath the rubber flap covering the hole in the metal tube you can judge 
of the opening of the valve. With respect to the systole and diastole, deter- 
mine the opening and closing of both valves. Do they both open at the 
same time? Reason? As to their closing? 
(g) With SB. closed, obtain fairly high Art. P. Maintaining the same number 
of strokes of even force, gradually open the SB. and note: 
1. Effect on Art. P. ? Is the rise synchronous with the systole of the pump ? 
Why? 
2. What condition of the vascular system does this represent? The stimu- 
lation of what nerve has this effect? 87 
MANUAL OF PHYSIOLOGY 
Exp. 48-Cardiac Inhibition, Pilocarpin and Atropin. 
Apparatus:-Turtle, turtle-board, bone saw, kymograph, heart lever, induc- 
tion coil, key, wire, signal magnet. 
(a) Destroy the brain of a turtle; fasten the turtle, back down, on board and 
with saw cut through the connections between the carapace and the plastron. 
Finish the removal of the plastron by cutting through the skin and other 
structures close to the plastron. Stretch the neck and hold the head in 
position by driving a nail through the jaw and into the board. Open the 
pericardium. Cut through the skin on the ventral side of the neck, separate 
the muscles and find the right vagus nerve. Isolate it and pass a loose 
thread under it. 
(&) Meanwhile let another student smoke a drum. Also arrange for repeated 
induction shocks. Place the signal magnet in the primary circuit and let 
the point of its pen write directly beneath the point of the heart pen. This 
will indicate time of stimulation. 
(c) When you think that you have found the vagus, verify this by stimulating 
it for a few seconds and note effect on heart. 
(d) Use suspension method as in Exp. 33. When you have recorded about 6 or 
7 beats on a medium speed drum and the two pens are in proper position, 
stimulate the vagus for 5 or 10 seconds and obtain inhibition. If none 
results, gradually increase the strength of the current. When proper 
strength of current has been found, make a tracing showing escape from 
inhibition, keeping the current on for a longer time. Does inhibition occur 
immediately after the beginning of stimulation 1 What is the period elapsing 
between these two events called ? Is the beat, if any, during this period the 
same as before stimulation? In which phase is the heart arrested? Notice 
and discuss the extent of the dilation during inhibition. How do the beats 
after stimulation compare with those before? Individual tracing. 
(e) Stimulate with repeated induction shocks the sino-auricular region and 
make tracing (group) of result. What structures were here stimulated? 
(/) Take 6 or 7 normal heart beats on the drum. Stop the drum. By means 
of a pipette apply a little 1% pilocarpin hydrochlorate to the heart. When 
a decided effect has taken place, record 4 or 5 beats. Stop the drum. Now 
apply some %% atropin sulphate and when it has taken effect record a few 
beats. Now stimulate first the vagus and then the sino-auricular region. 
Result? Explain. Group tracing. 91 
MANUAL OF PHYSIOLOGY 
Exp. 49-Reflex Inhibition of the Heart. Goltz's Tapping Experiment. 
Apparatus:-Frog board, induction coil, key, frog. 
(a) Destroy the cerebrum of a frog by cutting off the head just back ^f the 
eyes. This leaves the medulla uninjured. By as small an incision as possible 
expose the heart so that its rate can be observed. Do not pinch the legs of 
the frog too tightly down on the board as this may interfere with the experi- 
ment. Observe the condition of the heart (color and rate). Tap the abdom- 
inal wall in the region of the stomach with the handle of a scalpel at the 
rate of 50 or more per minute. Observe the reaction upon the heart. If 
heart stops, in which phase? Note the heart beats immediately succeeding 
the inhibition. What is the condition of the heart? Is it normal? What 
nerves and what parts of the central nervous system are necessary for this 
reflex act? 
(6) Cover the heart with moist filter paper. Expose a long stretch of the 
sciatic nerve, as directed in Exp. 50 (a). Do not stretch the nerve. Place 
two ligatures on it, close together, and cut the nerve between the ligatures. 
Stimulate the peripheral end with repeated induction shocks. Any effect 
on the heart? Stimulate the central end. Result? What kind of fibres 
did you stimulate? 
(c) Discard the platinum electrodes and use ordinary wires. Place one electrode 
on lower part of the spinal column and the other on the cut surface of the 
brain (be careful not to injure the medulla). Stimulate with medium 
strength repeated induction shocks. Explain results. While heart is in 
inhibition, prove that it is irritable by pricking it with a blunt pin. 
(d) Tilt ventricle upward and forward. Place electrodes on the under surface 
of heart (on sinus venosus) and stimulate. The inhibition frequently takes 
place after the electrodes are removed. 
(e) Now destroy the medulla and repeat (a). Does the heart stop now? Why? 
Repeat (d) and explain. 93 
MANUAL OF PHYSIOLOGY 
Exp. 50-Vaso-constrictors. 
Apparatus:-Platinum electrodes, web-board, curare, microscope, induction 
coil, key, thread, frog. 
(a) Pith brain of a frog and curarize very lightly. This paralyzes the nerve 
endings in the skeletal but not in the vaso-motor muscles. Place frog, back 
upward, on frog board, slit open the skin on the thigh a little inside of the 
median line. Carefully open the muscles without the use of a knife and 
expose the sciatic nerve. Take great care not to injure the blood vessels 
and do not stretch the nerve. Place a loose ligature under the nerve. Repeat 
for the other leg. Spread web of the left leg over hole of board-do not 
stretch it too tightly and keep it moist on both sides. 
(&) With low power observe the rate of circulation in a small vessel. Place the 
sciatic nerve of this leg on the electrodes and with repeated induction shocks 
just perceptible to the tongue stimulate for 2 or 3 seconds. Results? Ex- 
plain. What sort of nerve fibers were here stimulated ? Do not exhaust the 
nerve; let there be long periods of rest between the successive stimulations. 
(c) Now put the right sciatic nerve on the electrodes and while observing the 
same web as in (&) stimulate gently. Result? What kind of fibers were 
now stimulated? What sort of action is this? Prove it by cutting the left 
sciatic and stimulating the right nerve. Result? Explain. 
(d) Release the web for a few minutes. Place it in position, observe rate. With 
a brush apply a little adrenalin solution and note any difference. Reason ? 95 
MANUAL OF PHYSIOLOGY 
Exp. 51-Vaso-motor Mechanism. 
Apparatus:-Frog board, web board, a stand, microscope, two small dishes, 
two frogs. 
This experiment must be worked as quickly as possible. Avoid loss of blood- 
cut no more than is necessary; if the animal bleeds much, the results will be 
wrong. Two frogs of same size; destroy the brain of one and the brain and cord 
of the other. Be sure that the cord is destroyed; if it is, the frog will not jerk 
its leg when the toes are pinched (try this 5 minutes after frog has been pithed). 
Do not operate until you are sure of this. Expose the heart and intestines (cut 
a little to one side of the median line) in both frogs. Compare them as follows: 
1. Changes in color of the heart during systole and diastole. 
2. Fullness and force of the heart action. 
3. The condition of the blood vessels on the stomach and intestine. 
4. Place the frog on web board and observe circulation in the web (low 
power of microscope). 
5. Suspend the frogs, amputate one of the lower limbs (in thigh) and let 
the blood drop from the stump into a dish. Count the number of drops 
shed by each frog. Do not let any fluid from the abdomen mix with 
this blood. Explain in detail all the differences observed. 
-6. Brush a little adrenalin chloride over the exposed viscera of the cord 
pithed frog. Note changes in the vessels to which the adrenalin has 
been applied. Ts the heart affected? Also note any increased bleeding 
when the other hind leg is amputated. 97 
MANUAL OF PHYSIOLOGY 
Exp. 52-Vaso-constrictor Fibers in the Cervical Sympathetic. 
Apparatus:-Induction coil, key, wire, electrodes, animal holder, rabbit, ether. 
Lightly etherize a rabbit; place it on the holder. Cut the hair from the region 
over the trachea. Make a longitudinal incision through the skin and fascia over 
the trachea. By blunt dissection separate the mesial borders of the sternohyoid 
muscles, thereby exposing the trachea. Along side of the trachea and a little 
dorsal to it, you will find the carotid artery. Feel for the pulsation. Along the 
carotid artery lie three nerves. The largest and most distant from the artery is 
the vagus; the next largest lying next to the carotid artery and gray in color is 
the cervical sympathetic. The third nerve is the smallest, white in color, and lies 
in between the other two; this is the depressor nerve. 
Very carefully pass a loose ligature under the left sympathetic nerve. Hold 
the left ear up to the light, handling it very gently in order not to cause vaso- 
constriction or dilation. Notice the size of the blood vessels. "With a medium 
strength interrupted faradic current stimulate the sympathetic and note the 
result on the blood vessels. Also notice the condition of the pupil of the left 
eye. When these effects have been carefully observed and the blood vessels of 
the ear have come back to normal, place two ligatures on the sympathetic nerve 
and cut the nerve between the ligatures. Note effect on the vessels, also the 
color of the ear and its temperature as compared with the other ear. Stimulate 
the central end. Any effect on the vessels? Next stimulate the peripheral end. 
Effect? 
Discuss as fully as possible the functions of the cervical sympathetic as shown 
by this experiment. 99 
MANUAL OF PHYSIOLOGY 
Exp. 53-Action of the Mammalian Heart. 
Apparatus:-Animal board, trachea cannula, ether bottle, ether, key, elec- 
trodes, induction coil, thread, curved needle, bone forceps and saw, artery clips, 
artery cannulas, a dog. 
(a) Administer Chloretone by stomach tube. While this is taking effect, get all 
the instruments and apparatus ready. When the animal is nearly under 
place it on the holder and tie properly. Give ether if necessary. Place the 
iron pin of the head piece behind the canine teeth and tie the jaws firmly 
down to the pin. If necessary, clip the hair from over the trachea, and 
sternum; make a longitudinal cut through skin and fascia over the trachea. 
Separate the mesial borders of the sternohyoid muscles and expose the 
trachea. To the side of the trachea will be found the carotid artery and 
the vagus. Isolate the vessel and nerve on both sides and place a loose 
thread under each. With scissors make a transverse V-shaped cut in trachea 
(below larynx) and insert a trachea cannula. Tie a cannula securely by 
proper ligature but do not attach the compressed air tube until you are 
ready to open the thorax. 
(&) With a knife make a median incision through the skin and tissue of the 
thorax down to the end of the sternum. With bone saw and forceps cut 
through the sternum, being careful to keep on the middle line of the sternum 
(to avoid cutting the vessels) and keeping the lower blade of the forceps 
from stabbing into the organs beneath. As soon as the thorax has been 
punctured, artificial respiration must be begun, but do not inflate the lungs 
while the operator is in the act of cutting. If bleeding occurs use artery 
clips. Pull the thorax open gently and tie the retracted walls to the board, 
thereby exposing the heart. Observe:- 
1. Condition of lungs? Any evidence of anthracosis? 
2. Observe pericardium. Take it between your fingers, pull upon it and 
determine its thickness, strength and inextensibility. What are the 
functions of this structure? Slit it open and note the moisture on the 
heart. Source and object? 
3. The two auricles and two ventricles. The aorta and large veins. The 
coronary vessels. 
4. Palpate the right and left ventricles and note difference. Why ? Note 
that the ventricles harden during systole and soften during diastole. 
5. Note the color of the right and left auricles. Why this difference?' 
Thickness of their walls? 101 
MANUAL OF PHYSIOLOGY 
6. During systole the ventricles twist from left to right. Notice position 
of apex and the auriculo-ventricular groove. Also note the changes in 
the three diameters of the heart. What does this give rise to ? 
7. Place your finger on exposed carotid artery and note that the pulse is 
almost synchronous with the systole. Can you determine in an exposed 
artery the actual dilation of the artery during the pulse? Can you 
detect a pulse in the superior or inferior cava ? 
8. Press down with your finger on the appendix of the left auricle. Can 
you detect the beating of the mitral valve? 
9. Count the rate of beat per minute. Lift up one of the vagi and place 
on it two ligatures close together. Cut in between the ligatures. Count 
rate of heart. Stimulate the peripheral end with very weak repeated 
induction shocks. If no effect, gradually increase the strength of the 
current, and note the effect on auricles and ventricles. In which phase 
does the heart stop? Notice the greatly distended condition of the 
heart and of the large veins. What do you suppose is the condition of 
the venous pressure during cardiac inhibition? Why? While the heart 
is in inhibition prove that it is irritable. Which part of the heart, as 
it escapes, is the first to beat? Stimulate the central end of the cut 
vagus. Result on heart rate? How brought about? 
10. Raise one of the hind legs and expose the sciatic nerve by cutting 
through the skin in the middle of the posterior surface of the thigh. 
Cut through the subcutaneous tissue and separate the muscles until 
you see the sciatic nerve. Apply a ligature as low down as possible, 
cut below the ligature. Don't stretch the nerve. Count rate of heart; 
now stimulate the central end with weak faradic current and during 
stimulation count heart rate. If no effect, try a little stronger current. 105 
MANUAL OF PHYSIOLOGY 
11. Make a muscle-nerve preparation of a frog leg and place the cut end 
of the nerve on the heart. Notice that the muscle contracts at each 
heart beat (action current). 
12. Stop artificial respiration and note color of left auricle. Cause ? Note 
the rate of the heart beat. Resume respiration and notice how soon 
normal color is restored. Observe rate of heart. 
13. Raise the board so that the feet are up. Notice the effect on the rate 
and on the fullness of heart. Raise the head and observe. 
14. Compress the aorta with the fingers and note effect on the dilation of 
the auricles and ventricles. Compress inferior vena cava. 
15. If. Exp. 48, f, has been performed, you will omit this Exp. Count rate 
of heart. Apply a few drops of a 1% pilocarpin to the heart. Describe 
results. When heart is well under the influence of this drug, apply a 
little atropin. After 3 or 4 minutes count rate. Now stimulate 
the peripheral end of the vagus nerve. Discuss results. 
16. Place the electrodes on the heart and for 2 or 3 seconds send a moderate 
strength faradic current into the heart. Describe the result. What is 
this condition called? How does it affect circulation? Why? What 
is its usual outcome ? Notice which part of the heart stops last. 107 
MANUAL OF PHYSIOLOGY 
Exp. 54-Blood Pressure. 
Apparatus:-Same as Exp. 53; manometer with its attachments; 2 kymo- 
graphs, signal magnet, key, 1% pilocarpin, 14% atropin, amyl nitrite, adrenalin,' 
Ringer's solution, buret. 
(a) Administer ehloretone. If necessary give a little ether but be careful not 
to push this too far. 
(5) Set up inductorium for repeated shocks, placing signal magnet in the 
primary circuit. Smoke two drums. 
(c) The manometer should be half filled with mercury; the float should slide 
easily along the tube. Connect the central limb of the manometer with the 
pressure bottle containing a half saturated solution of sodium sulphate. To 
the T-tube of the manometer attach a piece of pressure tubing, to the other 
end of which affix the artery cannula. The wash-out tube of the cannula is 
.supplied with a short piece of rubber tubing and a clip. Place the manometer 
on a stand at such a height that the level of the mercury will be on a level 
with the carotid artery. Why? Let its pen come in contact with the drum 
(about 1/5 above the bottom of the paper). This level is the level of no 
pressure; adjust the pen of the signal magnet to write on this line and its 
curve will represent the base line. Do not change the level of this pen. 
(d) Perform tracheotomy (Exp. 53, a) ; expose the carotid artery and vagus 
nerve on one side and also the vagus on the other side. Apply loose liga- 
tures to each. Let another student at the same time expose the sciatic nerve 
on one side and the femoral vein on the other side. To expose the vein 
proceed as follows: Place your index finger over the inguinal region just 
at the lower border of the abdomen where the pulse of the femoral artery 
can be felt. With scissors cut through the skin and fascia. The triangle 
of Scarpa (Sartorius, Adductor longus, and External oblique M) will be 
seen, containing, from within out, the femoral vein and artery and anterior 
crural nerve. Clean the vein of its fascia for the distance of about one 
inch; apply an artery clip as high up as possible and after this ligature the 
distal end. Make a V-shaped incision (toward the heart) and insert a, 
cannula, tying it securely. 109 
MANUAL OF PHYSIOLOGY 
(e) When the carotid artery has been freed from its fascia, insert the cannu.'a 
attached to the pressure tubing. Raise the pressure bottle, open clip on 
the tube connecting it with the manometer and also the clip just in front of 
the cannula and the one on the wash-out. Catch the salt solution as it flows 
out of the wash-out (do not throw the solution away). By this all the air 
will be driven out of the tubes and cannula. When this has been accom- 
plished, close the wash-out and the cannula clips and cause a pressure of 
about 90 or 100 mm. in the manometer. Why? Be sure to close the clip 
on the pressure bottle tube. Why? Now open the clip on the cannula 
tube and the artery clip. The blood surges against the solution in the 
cannula and makes its pressure felt on the mercury of the manometer. Read 
the amount of pressure on the manometer scale. Take two or three inches 
of tracing. Observe two sets of waves. What are they called? Notice the 
synchronism of the more frequent curves with the pulse in the carotid 
artery, and that of the other waves with the respiration. Does the rise occur 
during inspiration or expiration? Cause? 
(/) Obtain two inches of normal tracing, then stimulate one of the vagi nerves 
with moderate strength current. If no effect, increase strength of current 
a little. Obtain a tracing that shows escape from inhibition. Individual 
tracing; label: "Blood Pressure, dog, Vagus Stimulation." All the other 
tracings of this experiment are group tracings. 
(g) Place two ligatures on the right vagus nerve, cut between the ligatures. 
Stimulate the central end of the vagus with weak current. This may cause 
a rise in blood pressure (pressor effect). Explain. Stimulation with strong 
current may cause reflex cardiac inhibition. Does this stimulation have any 
effect on respiration ? 
(A) Stimulate the central end of the cut sciatic nerve with repeated induction 
shocks (moderate strength). The blood pressure generally rises-pressor 
effect. Next stimulate with single shocks at the rate of one or two per 
second. It is possible to obtain a depressor effect: this is especially true 
if the animal is curarized. 
(i) Obtain about two inches of normal tracing on a slow drum and then close 
the trachea cannula to observe the effect of dyspnea upon blood pressure. 
At the moment of closing the trachea, press the key of the signal magnet 
(object?). Observe the condition of the pupil. Effect on blood pressure? 
Why? On the heart? As soon as the pressure begins to fall, open the 
trachea and observe effect on pressure. What are some of the causes of 
this increase in pressure? 113 
MANUAL OF PHYSIOLOGY 
O') Raise the foot-end of the dog board in such a manner that the carotid artery 
and the cannula maintain their previous height. By signal magnet indicate 
on the drum when this is being done. Hold the animal in this position for 
about 14 minute. Result on blood pressure and on rate of heart beat? 
Explain. Now lower the foot-end (same precaution) and note result. 
(k) Effect of amyl nitrite. Place a rubber tube on the trachea cannula and the 
other end of the tube in a wide mouth bottle. In this bottle put a few 
drops of amyl nitrite and cover the bottle loosely so that the animal will 
inhale some of the drug. Indicate on the drum by signal magnet. When 
the blood pressure begins to fall remove the rubber tube from the trachea 
cannula. The effect of the inhaled amyl nitrite will continue for some time. 
Why? Explain the fall in blood pressure. 
(?) Effect of adrenalin. Record an inch of normal tracing and then inject into 
one of the veins (either by hypodermic syringe or from a buret by means 
of the cannula in the femoral vein) one or two c.c. of adrenalin fl :10,000). 
Indicate time of injection on the drum. Watch the mercury in the mano- 
meter and do not allow it to pass beyond the bend of the manometer tube 
(Why?). Explain the effect on blood pressure. Was there any bleeding 
on the cut surfaces of muscles? Why? 
(m) When the blood pressure is fairly high, inject from % to 1 c.c. of 1% pilo- 
carpin solution, depending on size of dog. Note on drum by signal magnet. 
When the effect is quite evident, inject c.c. of 1% atropin. Explain the 
results. 117 
MANUAL OF PHYSIOLOGY 
(n) Air embolism. Kill the animal either by air embolism or by bleeding 
(see o) ; ask the instructor. After obtaining about an inch of normal 
tracing, force a small amount of air into the femoral vein. Note on the 
drum. Place a stethoscope on the chest wall and listen for the noise caused 
by the frothing of the blood in the heart. How long did it take for the 
blood pressure to fall? Extent of the fall? Explain. 
(o) Insert a cannula in the other carotid artery. Heat about 500 c.c. of physio- 
logical salt solution to 40° C. Fill a buret with this and connect with the 
femoral vein, making sure that all air has been expelled from the cannula. 
Obtain normal tracing. Open the clip on carotid artery and remove 50 or 
75 c.c. of blood (depending on size of dog). Indicate on drum. After a 
few minutes remove another 50 or 75 c.c., and continue this until the pres- 
sure is down to about 50 mm. Then inject warm salt solution in 50 or 75 
c.c. lots. Indicate on the drum and be sure not to admit any air into the 
vein. Describe the results. Bleed the animal to death while a blood pres- 
sure is being taken. How much blood was removed before blood pressure 
began to fall to any extent? Assuming 1/15 of body weight as blood, what 
% of the total volume of blood is this? How much blood was altogether 
removed? Why did the injection of salt solution increase blood pressure? 
Could the life of the animal be saved thereby? Upon what would that 
depend ? 119 
MANUAL OF PHYSIOLOGY 
Exp. 55-Circulation Time. 
Apparatus:-Buret, stand, clamp, rabbit, ether, methylene blue solution, 
thread, rubber membrane, artery clip, artery cannula. 
(a) Administer Chloretone to a dog or rabbit. Expose the right carotid artery 
and left external jugular vein. Under the artery place a piece of rubber 
membrane and between them a piece of white paper. 
(&) Place a clip on the vein and after the vein is well distended with blood 
apply a ligature an inch or so above the clip. Make a V-shaped incision in 
the vein between the clip and the ligature. Insert a cannula (pointing 
• towards the heart) securing it with a ligature. Fill the cannula with P.S.S. 
so that all the air is driven out. 
(c) Fill the buret with methylene blue (saturated sol. in 0.9% NaCl). Having 
made certain that all the air is out of the rubber tube attached to the buret, 
connect this with the cannula. 
(d) Open the clip and let about 2 c.c. of the methylene blue flow into the vein. 
Note the time accurately by watch (use the second hand). Now watch for 
the appearance of the methylene blue in the artery. Be sure that you have 
very good light upon the artery. The moment that a darker mass of blood 
makes its appearance note the time. Which circulation time is this? 
Exp. 56-Lymph Hearts. 
The lymph hearts of a frog are situated on either side of the posterior end 
of the urostyle. Pith the brain of a frog. Very carefully remove the skin from 
over them and study these structures. Is their action dependent on the central 
nervous system? Compare the rate of contraction of lymph hearts with that 
of the heart. Any relation? PART FIVE 
Respiration 
Exp. 57-Chest Measurements during Respiration. 
Apparatus:-A tape line, calipers, co-ordinate paper. 
Measure the circumference of the chest at the level of the axillae: (1) with 
chest wall at rest at the end of quiet expiration; (2) at the end of quiet inspira- 
tion; (3) at the end of most forcible inspiration; (4) at end of forcible expira- 
tion. Record the results in centimeters in the table below. 
With a pair of calipers measure the antero-posterior diameter of the chest at 
the junction of manubrium and the mesosternum and at the end of the sternum; 
record the results. 
Also measure the lateral diameter. 
Circumference 
Quiet Breathing 
Forced Breathing 
Inspiration 
Expiration 
Inspiration 
Expiration 
Diameter at 
top of Sternum 
Diameter at 
end of Sternum 
Lateral 
Diameter 
From the data obtained with the calipers, plot on co-ordinate paper the cross- 
section of the thorax in the four positions indicated. Let the backbone be the 
fixed point of all the curves, which are to be drawn the one within the other. 
121 123 
MANUAL OF PHYSIOLOGY 
Exp. 58-Respiratory Capacity; the Spirometer. 
Apparatus:-A spirometer. 
Sterilize the mouth piece with alcohol. Practice breathing through the mouth' 
piece of the spirometer (holding the nose shut) and notice the swing of the 
hand on the dial; the amount of air exhaled is indicated on the scale. 
(a) Place the spirometer at the zero mark; take a normal quiet breath and, 
without paying any attention to the spirometer, exhale to the usual extent 
through the mouth piece. Repeat six times. Take the average. What is 
this volume called 1 Note: 1 cu. inch=16.39 c.c. 
(6) Take another breath; expire the tidal air and after noting the scale, exhale 
as deeply as possible. What is this second quantity called? Take average 
of three readings. 
(c) Take in as much air as possible by a very forcible inspiration. Expire 
through the mouth piece, emptying the lungs as completely as possible. 
Read the scale and repeat twice. What is this quantity called? From the 
data obtained calculate the complemental air. Record the averages obtained: 
Tidal air 
c.c. 
cu. in. 
Supplemental air 
Complemental air 
Vital capacity 
(d) Count the rate of quiet respiration in a fellow student who does not know 
that he is being observed. Supposing that the rate of your respiration is 
the same, from the above data determine the amount of air respired during 
quiet respiration in one minute, one hour, one day. How much of the 
expired air is carbon dioxide? Calculate the amount (in liters and in grams) 
of this gas discharged in 24 hours. How much oxygen (in liters and in 
grams) is consumed in this length of time? 1 liter oxygen weighs 1.428 g.; 
1 liter carbon dioxide weighs 1.968 g. 125 
MANUAL OF PHYSIOLOGY 
Exp. 59-Respiratory Movements in Man. The Pneumograph. 
Apparatus:-Pneumograph, kymograph, signal magnet, tambour, plug-key, 
wire. 
With the T-tube open adjust the pneumograph around the chest and connect 
the nozzle with the rubber tube of the tambour. Close the T-tube. By the 
movements of the thorax the air pressure in the rubber tube of the pneumo- 
graph is altered; this is transmitted to the tambour. Record the excursions of 
the lever on the drum (medium speed) as also time in 3 seconds. Individual 
tracing; label "Pneumogram." Note the rate of the pulse. The subject should 
not look at the tracing while it is being taken, his attention being distracted 
as much as possible by reading. 
(a) Quiet respiration. From the tracing obtained determine:- 
1. The rate of respiration per minute; 
2. The relative duration of inspiration and expiration; 
3. The pause between inspiration and expiration; between expiration and 
inspiration; 
4. The relative speed of inspiration at the beginning and at the end of the 
phase; 
5. Also that of expiration; 
6. Ratio of heart beat to respiration. 
(b) Record 6 or 7 normal respirations and then let the subject thread a needle. 
Why is his respiration affected? Group tracing. 
(c) After obtaining 6 or 7 normal curves, let the subject breathe very deeply 
and slowly (18 per minute) for y2 minute and notice the curve following 
this. Cause of this change? Group tracing. 
(d) Obtain a small stretch of tracing while the subject is breathing carbon 
dioxide for a few seconds. Discuss the changes in rate, depth and rhythm. 
Group tracing. 129 
MANUAL OF PHYSIOLOGY 
Exp. 60-Artificial Respiration. Schaefer's Method- 
Apparatus:-A bed sheet. 
Shaefer's method "consists in laying the subject in the prone position, pref- 
erably on the ground, with a thick folded garment underneath the chest and 
epigastrium; extend the arms forward. The operator puts himself athwart or 
at the side of the subject, facing his head, and places his hands on each side 
over the lower part of the back (lowest rib). He then slowly throws the weight 
of his body forward, to bear upon his own arms, and thus presses upon the 
thorax of the subject and forces air out of the lungs. This being effected, he 
gradually relaxes the pressure by bringing his own body up again to a more 
erect position, but without moving his hands." Repeat this regularly 12 to 15 
times a minute. Each student of the group is required to be in turn subject and 
operator. The subject is to suspend voluntary breathing and to depend alto- 
gether upon the artificial respiration. Is this method efficient? 
Exp. 61-Factors Influencing the Respiratory Center. 
The respiratory center can be stimulated in three ways: chemically, reflexly, 
and psychically. 
(a) Breathe very deep at the rate of about 18 per minute for about 40 seconds. 
Immediately after this note the condition of respiration for the next 10 or 
20 seconds. What is this called? How can it be explained? What is this 
condition of the blood called? 
(&) Continue the deep but slow breathing for a longer length of time (2 or 3 
minutes). Notice tbe light-headedness and other disturbances. Also note 
that a great effort is necessary to keep up forced respiration. Why? 
(c) Place a large paper bag over your mouth and nose and repeat (a) and (b). 
Note the greater ease with which the forced respiration can be carried on 
and the absence of apnea. Explain. If this experiment was continued for 
a long time what would be the result? Why? 
(d) After a quiet respiration note how long you can hold your breath. How 
long after one deep inspiration? After two minutes of deep but slow respi- 
ration ? Explain. 
(e) Note how long you can hold your breath. After 4 or 5 minutes' rest sip 
water through a tube and notice how long respiration is stopped ? Explain.*- 
What nerve is here concerned ? Why is this of very great importance to us ? 
If the experiment does not succeed, proceed as follows: With the tube in 
your mouth, but not sipping water, hold your breath. When holding it any 
longer becomes uncomfortable and the "breaking point" is almost reached, 
begin to sip water. Result? Explain. 133 
MANUAL OF PHYSIOLOGY 
Exp. 62-Pulmonary Pressure. 
Apparatus:-Water manometer with tubing, Hg manometer, a bottle with 
a cork and inlet and outlet tubes, nose clip. 
(a) Arrange the apparatus as in Fig. 3; use the water manometer. Place the 
mouth piece, a, (after sterilizing it with alcohol) in the mouth. While 
breathing quietly through the nose note the excursions of the water in the 
manometer during inspiration and expiration. Convert the readings into 
mm. Hg. and record your results in the table below. 
Fig. 3. 
(&) Replace the water manometer by a mercury manometer and repeat as in 
(a) but respire forcibly. 
(c) Close the nose and make a forcible inspiration and expiration. Read scale 
and record. 
Note:-Be careful not to force the mercury out of the manometer. 
Quiet inspiration 
Pressure In mm. Hg 
Quiet expiration 
Forced inspiration 
Forced expiration 
Forced inspiration with air passages closed. . 
Forced expiration with air passages closed. . 
Exp. 63-Respiratory Sounds. 
Apparatus:-Stethoscope. 
(a) Vesicular Sound. Place stethoscope over the fifth or sixth right intercostal 
space and listen to the sound made during quiet inspiration, quiet expira- 
tion, forced inspiration and forced expiration. Note quality and duration 
of the sounds. 
(&) Bronchial Sound. With the stethoscope over the trachea or over the right 
second costal cartilage listen to the sounds produced during inspiration 
and expiration. Describe. 
(c) Vocal Fremitus. While the subject is counting listen to the sounds pro- 
duced in the thorax. Are the sounds heard distinctly? Can you feel the 
chest vibration with your hand? 135 
MANUAL OF PHYSIOLOGY 
Exp. 64-The Mechanics of Respiration. 
Apparatus:-The Respiration Scheme (Porter). 
Notice the following parts of the apparatus: 
(1) The wide glass tube with the rubber balloon which represents the thorax 
and lungs. (2) The tube opening into the lungs represents the trachea; to this 
is affixed a piece of rubber tubing with a hole which can be closed by the glass 
rod. (3) The trachea is connected with a manometer containing mercury which 
registers the pulmonary pressure. (4) One of the glass tubes leads into the 
pleural cavity and is connected with a water manometer recording the 
intra-thoracic pressure. This tube can also be opened to the external air by 
raising the glass rod in the rubber tubing affixed to the glass tubing. (5) The 
thorax is connected below with a rubber tube to the other end of which is 
attached a glass cylinder. 
In the glass cylinder place some water; elevate the cylinder so as to let the 
water flow into the thorax to the extent of about or % inch. The surface of 
the water in the thorax represents the diaphragm which can be lowered or raised 
by lowering or raising the glass cylinder; this corresponds to inspiration and 
expiration. Do not let the water come in contact with the lung. During the 
act of expiration the lungs must never be allowed to collapse to such an extent 
as not to be slightly stretched. 
(a) Open the opening in the tube mentioned under 4 (call this A) raise the 
glass cylinder till the water almost touches the lungs and then close A. Now 
with the tracheal aperture (call this B) only partly open, make inspiration 
and observe:-(1) intra-thoracic pressure, (2) pulmonary pressure, (3) in- 
flation of the lungs. Explain all these changes. Next produce expiration 
and again observe. 
(b) Observe the same with forced respiration. 
(c) Pneumothorax. Open A. Is there any change? Cause inspiration and 
expiration and describe results. 
(d) Adjust the apparatus as in (a). Close B almost entirely and note how the 
intra-thoracic and pulmonary pressures behave during inspiration and ex- 
piration. What condition in the animal does this represent? How is 
respiration affected by it? What effect will this have on the action of the 
heart and on the flow of blood? In what condition may this be followed by 
serious results? 
(e) In coughing a deep inspiration is followed by closure of the glottis; by a 
violent expiration and a sudden opening of the glottis the air is expelled. 
Demonstrate this on the model. Notice the pressures. 
(/) Sketch the apparatus, naming its various parts. 137 
MANUAL OF PHYSIOLOGY 
Exp. 65-The Vagus in Respiration. 
Apparatus:-Animal holder, dog, induction coil, key, electrodes, two time 
markers, tambour, stand, clamps, kymograph, Woulff bottle. 
(a) Administer small dose of Chloretone; give ether if necessary. Place the 
animal on a holder and expose the vagi nerves. Place ligatures under the 
nerves but do not tie them. To make certain that you have the vagi nerves, 
stimulate them with repeated induction shocks and watch for cardiac 
inhibition (disappearance of the pulse in the exposed carotid artery). 
(&) Perform tracheotomy. To one of the limbs of the trachea cannula attach 
a piece of rubber tubing provided with a screw clamp. Connect the other 
limb of the cannula with one of the outlets of a Woulff bottle and connect 
the Woulff bottle by means of a rubber tube with a tambour. Let the lever 
of the tambour write on a medium speed kymograph. By chronograph 
record time in two seconds. Place a second signal magnet in the primary 
circuit of the induction coil in order to indicate the various steps in the 
experiment. 
(c) To obtain proper excursion of the tambour lever and thus a good tracing, 
it may be necessary to partly close the free end of the trachea cannula. 
Obtain a short stretch of normal respiration curve. 
(d) When 6 or 7 movements have been recorded place two ligatures on the left 
vagus nerve and cut in between them. Indicate on drum by signal magnet. 
Group tracing. Note effect of this on the rate and depth of respiration. 
(e) Take an inch or two of tracing and then stimulate the central end of cut 
vagus with a weak interrupted current. Gradually increase the strength 
of current. What effect? Stimulate peripheral end and discuss results. 
Individual tracing. 
(/) Expose the sciatic nerve and stimulate the central end with faradic current. 
This and all following tracings are group tracings. 
(g) Stimulate the superior laryngeal nerve (indicate on drum) by introducing 
into the larynx a probe wrapped with a little absorbent cotton. Explain 
the result. Advantage of this reaction? 
(7t) Close the trachea cannula (indicate on drum) and study the effect of 
dyspnea. 
(i) Cut the other vagus nerve (indicate on drum). How is the rate affected? 
The depth ? What relation between these two changes ? Observe that these 
changes are not temporary. 
(j) Bleed the animal, as in Exp. 54 (o), until the animal is dead. Note the 
various changes in respiration. 141 
MANUAL OF PHYSIOLOGY 
Exp. 66-The Influence of Acid and Alkali on the Respiratory Center. 
Apparatus:-%% acetic acid, ^% sodium carbonate, kymograph, signal 
magnet, plug-key, stands, clamp holders, dog, ether, 2 burets, tambour. 
(a) Etherize a dog lightly. Record the respiratory movements as in Exp. 65. 
Expose both femoral veins (Exp. 54, d) and insert cannulas. Fill cannulas 
with 0.9% NaCl (remove all air) and connect with burets. Fill the one 
buret with %% acetic acid and the other with ^% sodium carbonate. Let 
the signal magnet write below tambour pen. 
(6) Obtain a stretch of normal tracing; medium or slow speed of drum. Now 
inject two or three c. c. of acetic acid (indicate on drum) ; if no effect, inject 
more. When this has produced a marked effect, inject a small quantity of 
the carbonate until it neutralizes the effect of the acid. Group tracing. 
Discuss the results of this experiment and show its bearing on the normal 
activity of the respiratory center. 143 
MANUAL OF PHYSIOLOGY 
Exp. 67-Intra-Thoracic Pressure. Phrenic Nerve. 
Apparatus:-Manometer with, tubing and pinchcock, trachea cannula, bone 
saw and forceps, thread, key, induction coil, shielded electrodes, dog, cannula, 
(a) Administer Chloretone, expose the trachea; insert a cannula. Connect a 
glass cannula with a water manometer; color the water with eosin. Make 
a very small cut in the skin over the 4th intercostal space on right side 
and make a very small aperture through the intercostal muscles. Through 
this opening gently force the glass cannula, with as little motion as possible, 
so that its end lies in the pleural space. There should be no leakage around 
the cannula and the tissues. Note pressure registered during inspiration 
and expiration. What pressure here measured? Where does this pressure 
exist ? Its origin ? Its variations ? 
(6) By cutting along the linea alba open up the abdomen so that the action of 
the diaphragm can be observed. Notice the central tendinous part and the 
course of the fibers in the muscular portion. Notice the descent of the dia- 
phragm during inspiration (if necessary close the trachea cannula for a 
few seconds). Shape of diaphragm? Does the central part move during 
quiet respiration? During forced respiration? 
(c) Open up the thorax according to Exp. 53 (b). Find, the phrenic nerves; 
isolate, but do not cut them. By means of shielded electrodes stimulate one 
of them with weak induction shocks. Notice the diaphragm. Stimulate the 
other phrenic. 
(d) For a short period suspend the artificial ventilation of the lungs. Dyspnea 
will result and the animal will make inspiratory effort; notice the diaphragm. 
Immediately cut both nerves. Effect? Stimulate the central end of one 
phrenic; next the peripheral end. Discuss the nature and function of these 
nerves. Kill the animal by causing delirium cordis (Exp. 53, 16). 145 
MANUAL OF PHYSIOLOGY 
Exp. 68-The Reducing and Oxidizing Power of Tissues. 
Apparatus:-Methylene-blue solution, ammonium sulphide, hydrogen per- 
oxide, liver, 1% potassium cyanide, test tubes. 
(a) In a test tube place about 5 c.c. of water and 10 drops of H,O2. Is there 
any gas liberated? Now add to it a piece of liver. What is the result? 
What substance in the liver is held responsible for this? To what class of 
substance does this belong? Boil a small piece of liver for 5 minutes and 
repeat the above. Does the result agree with your answer to the last 
question ? 
(&) In the above experiment what gas is liberated? Devise an experiment to 
prove this. 
(c) To 5 c.c. of methylene-blue solution add one drop of ammonium sulphide; 
shake it slightly. The methylene-blue has been reduced to a colorless com- 
pound. Shake it thoroughly and let it stand till the next laboratory period 
if necessary. 
(d) To some methylene-blue which has been decolorized as described above, add 
about 10 drops of H2O2. Any change visible? Now add a small piece of 
liver and let it stand at 37 degrees C. for some time and note the change. 
Explain. 
(e) Repeat (d) with a piece of boiled liver. Why are the results different from 
those obtained in (d) ? 
(f) To 10 c.c. of methylene-blue solution add 2 or 3 small pieces of raw liver. 
To another 10 c.c. add a piece of boiled liver. In a third test tube place 
10 c.c. methylene-blue, a piece of liver and 1 c.c. of potassium cyanide solu- 
tion. In a fourth test tube put some methylene-blue for comparison. Cork 
and set all four test tubes aside for *4 hour or more. Shake the test tubes 
occasionally. Explain results. PART SIX 
Alimentary Canal 
Exp. 69-Deglutition. 
Apparatus:-Stethoscope. 
(a) This experiment must be conducted in a quiet room. Place the stethoscope 
over the region of the larynx of a fellow student. While he is taking a 
swallow of warm water, note the sound and the interval between the swal- 
lowing and the hearing of the sound. Now place the stethoscope over the 
end of the sternum or over the sixth rib a trifle to the left of the spinal 
column and listen for the sound. Note character of the sound and the 
length of time taken for the water to enter the stomach. 
(&) Repeat this experiment while the subject is swallowing solid food. How 
does this deglutition time compare with that found in (a) ? Why this 
difference ? 
Exp. 70-Secretion of Pancreatic Juice. 
Apparatus:-Induction coil, key, electrodes, dog, 0.4% HC1, cannula, artery 
clip. 
(a) Administer Chloretone to a dog. Open up the abdominal cavity and locate 
the duodenum and pylorus. Locate the pancreas. Slit open the duodenum 
and locate the papilla of Vater. In this is the opening of the common bile 
duct and the duct of Wirsung from the pancreas. The ductus Santorini 
opens about an inch or two farther down. Insert a cannula into the duct 
of the papilla and place an artery clip on the common bile duct. If pan- 
creatic juice flows, collect it in a dish. 
(6) Expose one of the vagi nerves in the neck, double ligature it and cut be- 
tween the ligatures. Stimulate the peripheral end with single induction 
shocks, once per second. 
(c) Place about 15 c.c. of 0.-4% HC1 in the duodenum and note the result on 
the flow of pancreatic juice. Explain the results. 
147 149 
MANUAL OF PHYSIOLOGY 
Exp. 71-Peristalsis. 
Apparatus:-Trachea cannula, barium chloride, calcium chloride, physostig- 
min, atropin, a rabbit. 
(a) Lightly etherize a rabbit. Perform tracheotomy so that artificial respira- 
tion can be instituted if necessary. Keep the animal warm. By cutting 
along the linea alba expose the small intestines. If spontaneous movements 
occur, note both the peristaltic and the pendular movements. 
(&) Pinch a quiescent loop and note the contraction and the relaxation (where?) 
of the intestines. What law is here demonstrated ? Repeat with ascending 
colon. 
(c) To a loop of the small intestines apply a drop of 1% barium chloride. Re- 
sult? Now apply a few drops of calcium chloride. 
(d) To another loop apply a drop of 1/1Q% physostigmin. Neutralize this 
effect by applying 1/10% atropin. 
(e) Examine the mesentery. Are the lacteals visible? Color? If so, you may 
be able to notice the beaded appearance due to the constrictions at the 
lymphatic valves. Locate the receptaculum chyli opposite the kidneys. 
Exp. 72-Fat Absorption. 
If part (e) of Exp. 71 was not successful, perform the following experiment. 
Chloroform a cat that has been fed two hours previously with cream; open the 
abdominal cavity and examine the mesentery. Look for the lacteals. Color? 
Why? Examine the thoracic duct; open it. Any flow? Nature of fluid? 151 
MANUAL OF PHYSIOLOGY 
Exp. 73-Rapidity of Absorption and Secretion. 
Apparatus:-Potassium iodide in capsules, starch paste, nitric acid, test tubes. 
(a) To 5 c.c. of thin starch paste and 2 c.c. strong nitric acid add a drop of 
potassium iodide solution. Result? Chemical equation? 
(&) In each of ten test tubes place 3 c.c. thin starch paste and 1 c.c. nitric acid. 
Let one student of the group swallow a capsule containing % gram KI. 
Rinse your mouth thoroughly. At 2-minute intervals expectorate some of 
the saliva into one of the test tubes and note how long after swallowing 
the KI it appears in the saliva. To quicken the flow of saliva, let the student 
chew a piece of paraffin or rubber. Describe the pathway of the KI in 
the body. 
Exp. 74-Auto-digestion. 
One hour after feeding a rabbit or dog kill the animal by chloroform. Liga- 
ture the two openings of the stomach and remove it. Open the stomach, catching 
the contents in a large dish. Note the consistency of the contents and its reaction 
to litmus and to dimethyl-amino-azobenzol. What does this demonstrate ? Rinse 
the stomach with water and place it in an incubator at 40° C. Note the condi- 
tion of the mucosa after a sufficient length of time. Explain. How can we 
explain the absence of this process in the body ? PART SEVEN 
Sweat and Urine 
Exp. 75-Scretion of Urine. 
Apparatus:-Induction coil, key, electrodes, indigo-carmine, 1 % urea solution, 
cannulas, dog. 
(a) Administer chloretone to a dog. Expose the external jugular vein and 
insert a cannula; connect this cannula with a buret for injection, having 
carefully filled the cannula with physiological salt solution in order to re- 
move all air. Expose one vagus nerve, ligate it and cut it central to the 
ligature. Open the abdominal cavity, locate the ureters. Insert a straight 
cannula in each and connect them to a Y-tube so as to collect the urine. If 
there is a spontaneous flow of urine, count and record the drops per minute. 
(&) Into the vein inject 20 c.c. of a 1'% urea solution. Note rate of urine 
secretion, after a short latent period. 
(c) Stimulate the peripheral end of vagus. Effect on urine secretion? Why? 
(d) Introduce 5 c.c. of a saturated solution of indigo-carmine into a vein and 
note how long a time elapses before the pigment is found in the urine. 
Exp. 76-Secretion of Sweat. 
Apparatus:-Induction coil, key, electrodes, pilocarpin, atropin, dog. 
(a) Administer chloretone to a dog. Expose the sciatic nerve of the left leg, 
and the femoral vein on the right side. Observe the pad of the left foot; 
if there is any evidence of sweat, dry the pad. Now stimulate the peripheral 
end of the cut sciatic nerve with repeated induction shocks and carefully 
look for droplets of sweat on the pad of the foot. To what class of nerves 
do the sudoriferous nerves belong? 
(6) Into the vein inject 2 or 3 c.c. of 1/10%, atropin; stimulate the sciatic. 
Result ? 
(c) Now inject 1 c.c. of 1% pilocarpin and again stimulate the sciatic. Observe 
the pad of the foot for sweat. Result? Explain. 
153