Prize Paper 
ON 
PHYSIOLOSY and HISTOLOGY. 
BY / 
=v/ 
MARY WOLFE, 
Class op isss, 
Pulte Medical College, 
CINCINNATI 
1882. 146 SMITH STREET, CINCINNATI, 0., 
Professor J. M. CRAWFORD, 
March 10, 1882, 
Dear Sir : 
The complimentary terms in which you spoke 
of Mary Wolfe’s written examination in Physiology and 
Histology in your public speech, at the Commencement Exer- 
cises of Pulte Medical College, at College Hall in the Mercan- 
tile Library Building in this city, March 1st, 1882, and to 
memorialize which was awarded an elegant gold medal, have 
caused many personal friends to express a desire to read it. 
Will you be kind enough to allow me a verbatim copy of 
her paper? 
Yours truly, 
N. B. WOLFE. 
COR. SEVENTH AND MOUND, CINCINNATI, 0., 
Dr. N. B. WOLFE, 
March 11, 1882. 
Your note of yesterday is before me, asking for 
a verbatim copy of your daughter’s examination paper, and I 
cheerfully comply with your request. 
The committee that awarded the medal to Miss Mary 
Wolfe did so with entire unanimity. Her paper was best in 
that comprehensive sense which includes general scholarship, 
as well as physiological knowledge. The reading of it, I trust, 
will show to yourself and friends, as it did to the members of 
the committee, that the medal was worthily bestowed. 
Dear Sir : 
I am sincerely yours, 
J. M. CRAWFORD. INTRODUCTION. 
It will be a matter of interest to our friends to learn 
the circumstances under which the following paper on Phys- 
iology and Histology was written, and how the award of 
the gold medal was made. 
Professor J. M. Crawford announced to the members of 
his class that he desired them to assemble in the amphi- 
theater of the college, on Wednesday, at ten o’clock, A. M., 
of examination week. When they came together, he 
handed to each student a paper containing the following 
examination questions: 
I. Name the Contents of the Respective Regions of the Anterior 
Portions of the Chest, and give the Signs of Normal Func- 
tions of the Organs in each Region. 
II. Give the Divisions of Proximate Principles of the Blood, and 
the Important Peculiarities of each. 
III. Describe fully the Process of Mastication, and give the Mech- 
anism of Deglutition. 
IV. Describe Saliva, Gastric Juice, Pancreatic Juice, and give the 
Mechanism of their Secretion and the Function of each. 
V. In the Digestive Process, give the Successive Steps by which the 
Food finally enters the Blood. 
VI. Give the Relations of the Nervous System to the Glycogenic 
Function of the Liver. 
VII. Give the Physiological Anatomy of the Kidney, and Mechanism 
of the Secretion and Excretion of Urine. 6 
INTRODUCTION. 
VIII. Give the Mechanism of Respiration, and the Means by which 
Oxygen is conveyed to the Tissues. 
IX. Give the Mechanism of the Continuous Flow of Blood in the 
Veins, and the Cause of a Systemic Venous Pulse. 
X. Describe fully a Nerve, and give its Physiological Properties. 
The Professor supplemented these questions by stating 
that during the examination the students were expected 
not to converse with each other, nor to ask questions or 
refer to memoranda. In short, the class was given to 
understand that every student was expected to do square 
work. As each paper was finished it was delivered to Pro- 
fessor Crawford, who was present during the entire exam- 
ination. 
At the commencement exercises of Pulte Medical Col- 
lege, in College Hall of the Mercantile Library Building, 
March 1, 1882, after the addresses and valedictory had been 
delivered, the Dean of the college, Professor J. D. Buck, 
announced that “ the next thing on the printed programme 
is the delivery of the diplomas to the graduating class; but, 
before doing this, one of the exercises of the evening, not 
set down, as it should have been, will now take place.” 
Hereupon Professor J. M. Crawford came to the front of 
the rostrum, and said substantially: 
“A friend to education and to Pulte Medical College, 
who does not wish his name made public, but who enter- 
tains a high appreciation of the study of Physiology and 
Histology, as constituting the foundation of a reliable med- 
ical education, in order to encourage application and reward 
success, placed in my hands, early in the term, funds to 
provide an annual prize, to be presented to the student who 
gives the best examination paper in this department of med- 
ical study. This award will be called ‘ The Unknown 
Prize,’ and, like the Protean body, will take any shape 7 
INTRODUCTION. 
that may seem at the time best calculated to reward the 
victorious competitor. This year it takes the form of a 
gold medal. Whence it comes you will never know ; but 
whither it goes, each succeeding commencement, during my 
connection with the college, will reveal. 
“The duty of selecting the one entitled to receive this 
award has been scrupulously performed by the Professor 
of Physiology, assisted by the Dean and other members of 
the Faculty. Among the papers of merit which they have 
examined and indorsed as worthy of honorable mention, 
there was one that attracted special attention, and com- 
manded the admiration of the examining committee. This 
paper was found not only to be unusually comprehensive and 
exact in its grasp and arrangement of physiological and his- 
tological facts, but its statements were clear, concise, and 
in classic English. 
“The prize I hold in my hand. You perceive it has 
the shape of a Greek cross, the base modified to resemble 
the human heart. On the face of the top section of the 
cross is engraved the symbol of the astral lights, a dual tri- 
angle forming a star, in the center of which is the radiant 
face of the sun. On the right section appears Mercury, 
with Avinged feet, walking upon a troubled sea, himself re- 
splendent in the ambient air, bringing his appropriate mes- 
sage. On the left is ornately engraved a representation 
of Hygeia, the daughter of Esculapius, in the attitude of 
receiving light for her lamp from the emblem of wis- 
dom, the serpent. The lower part of the cross is heart- 
shaped, on which is engraved the mundane egg, the mother 
source of natural life. Thus are symbolized in this beau- 
tiful jewel, the four elements, Fire, Water, Air, and 
Earth, associated with Wisdom, all contributing to Health. 
The circle in the center of the cross contains a beautiful 
enameled monogram, surrounded, in engraved Greek char- 8 
INTRODUCTION. 
acters, with the well-known motto, I'viofti Zeolutov, ‘Know 
Thyself.’ On the reverse of this medal is inscribed this 
personal legend: 
AWARDED 
miss T&avy Mlolf*, 
TO 
FOR THE 
Best Written Examination 
IN 
PHYSIOLOGY AND HISTOLOGY, 
Pulte (£oI[r<je, 
Cincinnati, March ist, 1882 
“My duty is now done. Miss Wolfe, receive your 
medal. I trust the success which this symbolizes will stimu- 
late you to still greater efforts in the pursuit of knowledge.” Physiology and Histology. 
I. 
Name the Contents of the Respective Regions in 
the Anterior Portion of the Chest, and give 
the Signs of Normal Function in each Region. 
A. SUPRA-CLAVICULAR REGION. 
Contents. On both sides it contains the apices of the 
lungs, the common carotid arteries and jugular veins, and 
the subclavian arteries and veins. 
Signs of Normal Function. On palpation is found the 
pulsation of the carotid arteries; on percussion, pulmo- 
nary resonance; on auscultation, pure vesicular murmur, 
and scarcely audible voice. 
B. Clavicular Region. 
Contents. On both sides is found vesicular lung struc- 
ture. On the right side are the innominate and subclavian 
arteries and their accompanying veins. On the left side are 
the common carotid and subclavian arteries, with their 
veins. 
Signs of Normal Function. On palpation, the clavicle 
is felt; on percussion, dullness, and high-pitched resonance 
result; on auscultation, pure vesicular murmur, and scarcely 
audible voice are heard, except at the sternal end, where are 
found bronchial breathing and bronchophony. 10 
PULTE COLLEGE PRIZE PAPER. 
C. Infra-clavicular Region. 
Contents. On both sides are found the vesicular struc- 
ture of the lungs, and the main branches of the bronchial 
tubes. On the right side, the vena cava and aorta are 
found, the right bronchus, the bronchial artery and vein. 
On the left side is a portion of the pulmonary artery, the 
bronchial artery, the left bronchus, and the vein. 
Signs of Normal Function. On palpation, vocal fremitus 
is felt, more on the right side; on percussion, pulmonary 
resonance results; on auscultation, scarcely audible voice, 
and pure vesicular murmur, mixed with bronchial breathing, 
blended throughout the whole region, are heard, the vesicu- 
lar murmur being more distinct toward the axillary region, 
the bronchial breathing toward the sternal; the heart sounds 
are found on the left side, at the lower border of this region. 
D. Mammary Region. 
Contents. On both sides are lung structure and bron- 
chial bifurcations. On the right side the heart’s border is 
found behind the lung; also, on deep inspiration, the liver, 
when it rises to a level with the fifth rib. On the left side 
the lung is moved aside for the heart; beginning at the 
fourth sterno-costal articulation, extending down to the fifth 
intercostal space, and returning again at the sixth. 
Signs of Normal Function. On palpation, there is slight 
vocal fremitus; on percussion, there is resonance on both 
sides, except on the left, over the region of the heart, where 
there is dullness and higher pitch ; on auscultation, there is 
feeble vesicular murmur on the right side below, on both 
sides above; on the left side, at the junction of the third 
rib with the sternum, is heard the second sound of the 
heart; at the junction of the fourth rib with the sternum is 
heard the first sound of the heart. These are the points of PHYSIOLOGY AND HISTOLOGY. 
11 
greatest intensity; the sounds are propagated into the sur- 
rounding area, and diffused throughout the chest. The 
voice is hardly audible. 
E. Infra-mammary Region. 
Contents. On the right side is found the liver; in the 
superior portion of the region the lung is in front of it. 
On the left side are the anterior portion of the base of the 
lung, a small part of the left lobe of the liver, the anterior 
border of the spleen and the cardiac end of the stomach. 
Signs of Normal Function. On palpation, resistance 
from the presence of the liver, and the apex beat of the 
heart are found; on percussion, dullness and high pitch 
over the region of the liver and spleen, and tympanitic 
resonance over the stomach, result; on auscultation, vesicu- 
lar murmur is heard on both sides. 
F. SuPRA-STERNAL REGION. 
Contents. The trachea, and sometimes the tip of the 
transverse portion of the arch of the aorta, are found; also 
the arteria innominata at its lower border. 
Signs of Normal Function. Palpation and percussion 
are of little value here; on auscultation, tracheal breathing 
is heard. 
G. Superior or Upper Sternal Region. 
Contents.* The division of the trachea, the aorta, and 
great vessels are found here. The heart lies partly in this 
region. The pulmonary valves are on a level with the 
third rib, the aortic valves below. 
Signs of Normal Function. Palpation reveals the pres- 
ence of the sternum; on percussion there is clear resonance 
of high pitch; on auscultation, bronchial breathing, bron- 
chophony, and reflected heart-sounds are heard. 12 
PVLTE COLLEGE PRIZE PAPER. 
H. Inferior or Lower Sternal Region. 
Contents. The anterior mediastinum above, the stomach 
below, a part of the heart and a small portion of the lung 
on its right border are found; also the attachment of 
the pericardium to the diaphragm. The mitral valves are 
situated near the left side at the sterno-costal articulation 
of the fourth rib ; the tricuspid valves are nearer the me- 
dian line, below the aortic valves. 
Signs of Normal Function. On percussion, resonance is 
clear in the upper part of the region, and tympanitic in the 
lower part; on auscultation, the heart-sounds are heard. 
The first sound is synchronous with the closing of the au- 
riculo-ventricular openings ; the second, with that of the 
pulmonary and aortic. The normal heart-beat may be di- 
vided into four periods: the first sound occupying four- 
tenths of the time; the first rest, one-denth; the second sound, 
three-tenths; the second rest, two-tenths. Pure vesicular 
murmur is heard above, and but feebly below. The voice 
is hardly audible in this region. PHYSIO LOG Y AND HISTOLOG Y. 
13 
II. 
Give the Divisions of the Proximate Principles 
of the Blood and the Important Peculiarities 
of Each. 
The proximate principles of the blood are found in the 
plasma. They may be divided into five classes, as below: 
A. Organic Nitrogenized. 
These are intimately connected with the vital principles, 
and enter directly into the nourishment of the tissues. They 
are all in a state of continual change in the body, con- 
stantly wearing out and becoming effete, when they take 
the form of excrementitious substances. This class of 
proximate principles is of organic origin exclusively; they 
are not crystallizable, and are of indefinite chemical com- 
position. Plasma is largely made up of them; fibrin, plas- 
min, paraglobulin, metalbumin, and fibrinogin are examples. 
B. Organic Non-nitrogenized. 
These principles are essential to development and nour- 
ishment. They are deposited in the tissues, and are seem- 
ingly stored there for emergencies. They usually exist in 
the blood in but small quantities, and are derived from the 
food; the glycogenic matter comes partly from the food 
and partly from the liver. They are of definite chemical 
composition. The fats, sugars, and starches are examples. 14 
PULTE COLLEGE PRIZE PAPER. 
C. Organic Saline. 
These principles are formed in the body by true chem- 
ical union. Pneumates and lactates are examples. 
D. Inorganic. 
These are principles not formed in the organism, and 
that remain unchanged while in the body. They are of 
definite chemical composition, and are crystallizable. The 
substances forming these are introduced from without the 
body, and are discharged from it in the same chemical 
form in which they entered the organism. In the body, 
however, they behave as organic principles, and are neces- 
sary for nutrition. The carbonates, phosphates, sulphates, 
water, and sodium-chloride are examples. 
E. Excrementitious. 
These are the waste principles and poisonous matter 
from the system, and result from the breaking down of 
tissues. Urea, carbonic acid, and cholesterin are examples. 
Cholesterin is a principle separated from the blood, in all 
probability, as shown by Flint and Muller, through the 
excrementitious function of the liver, and is discharged in 
the form of stercorin with the faeces. Urea is mainly dis- 
charged in the urine and sweat, the excrementitious fluids 
of the organism. 15 
PHYSIOLOG Y AND HISTOLOG Y. 
III. 
Describe fully the Process of Mastication, and 
give the Mechanism of Deglutition. 
A. Mastication. 
Mastication is the process of dividing the food by the 
teeth, assisted by the tongue, cheeks, and lips, to prepare it 
for deglutition. 
Mechanism. The movements in mastication are those 
of the lower jaw, the tongue, cheeks, and lips. 
The lower jaw has three movements, a vertical, a lat- 
eral, and an antero-posterior. The vertical movement is an 
upward and downward motion. The upward motion, or 
closing the jaws, is caused by the contraction of the tem- 
poral, masse ter and internal pterygoid muscles. The down- 
ward motion, or opening the jaws, is caused by the action 
of the digastric, the mylo-liyoid, the genio-hyoid, and the 
platysma myoides muscles. The lateral and the antero- 
posterior movements are caused, the former by the contrac- 
tion of the muscles that elevate the lower jaw, acting uni- 
laterally ; the latter by the anterior and posterior portions 
of the pterygoid muscles contracting separately. 
The tongue is in active and eccentric motion, the in- 
trinsic fibers and extrinsic muscles both being engaged. 
The muscles of the cheeks and lips act, also, in helping 
to keep the food between the teeth. 
After the bolus is thoroughly masticated and insalivated, 
it is ready for deglutition. 16 
PULTE COLLEGE PRIZE PAPER. 
B. Deglutition. 
Deglutition may be divided into three stages. The first 
stage is voluntary, and extends from the time the food is 
pushed back, after being masticated, collected into a bolus, 
and insalivated, until it enters the isthmus faucium. The 
second stage extends from the time the food enters the 
isthmus faucium until the constrictors of the pharynx grasp 
it. The third stage extends from the time it enters the 
grasp of the constrictors until it reaches the oesophagus. 
The First Stage. After the thoroughly masticated and 
insalivated bolus of food is forced back by the tongue, it 
rests on the posterior portion of that organ, which presses 
against it, and which is also applied to the roof of the 
mouth to prevent the return of the bolus. By this press- 
ure of the tongue it enters the isthmus faucium. 
The Second Stage. After the bolus has been pressed into 
the isthmus of the fauces, the tensor palati renders the soft 
palate tense; the levator palati draws it upward; at the 
same time the posterior pillars of the isthmus faucium con- 
tract, the chink between them being filled by the azygos 
uvulse; the stylo-pharyngeus acts in concert now, and pulls 
the pharynx back, like the finger of a glove. This brings 
the roof in apposition to the superior constrictors, and ex- 
cites just enough action in them to grasp it, thus closing 
the opening into the posterior nares. At this time the 
larynx is being raised by its five levators, the digastric, the 
stylo-hyoid, the mylo-hyoid, the genio-hyoid, and a few fibers 
of the hyo-glossus. The epiglottis is now covering the glot- 
tis, the floor of the pharynx is now an inclined plane, and 
the anterior pillars, the palato-glossus muscles, now contract- 
ing, force the bolus along this plane into the grasp of the 
superior constrictors. PHYSIOLOGY AND HISTOLOGY. 
17 
The Third Stage. The constrictors, the superior, mid- 
dle, and inferior, contract upon the bolus from above 
downward, and thus it is forced into the upper opening of 
the oesophagus, to be conveyed thence to the stomach by 
the peristaltic action of the oesophageal muscles. 18 
PULTE COLLEGE PRIZE PAPER. 
IV. 
Describe Saliva, Gastric Juice, Pancreatic Juice, 
and give the Mechanism of their Secretion 
and the Function of each. 
A. Saliva. 
Description. Saliva is a fluid which is secreted by glands 
situated around the cavity of the mouth. It is rather tur- 
bid, somewhat viscid, almost tasteless, and its reaction is 
alkaline. The turbidity is caused by the presence of epi- 
thelial cells, which are mixed with the salivary secretion. 
These cells come from the mucous glands of the mouth, 
and from the ducts of the salivary glands. 
Mechanism of. Secretion. The salivary glands are race- 
mose glands, situated in the buccal cavities, in the fossae of 
the lower jaw, and under the posterior portion of the 
tongue. They are lined with mucous membrane, and the 
investing epithelium differs in the ducts and in the glands. 
The glands proper, or terminations of the ducts, are lined 
with spheroidal or true glandular epithelium. The ducts 
are lined with columnar epithelium. In the body of the 
gland the proper secretion is separated from the blood. 
This’is the function of the true gland cell wherever found. 
The epithelium lining the ducts secretes mucus. The glands 
and their ducts are : 
The parotid, with Steno’s duct. 
The submaxillary, with Wharton’s duct. 
The sublingual, with the small ducts of Riviere. 19 
PIIYS/OL or, V AIVD H/STOLOGY. 
The secretion from the parotid is least viscid; that 
from the submaxillary next; and that from the sublingual 
most of all. 
Function. The principal office of the saliva is, mechan- 
ically, to moisten the food and thereby assist deglutition; 
and, chemically, to thoroughly change the starches into 
dextrin, and then into sugar, either in the mouth or after- 
wards in the stomach. 
The active principle is ptyalin. 
B. Gastric Juice. 
Description. Gastric juice is a fluid clear and amber- 
colored, with an acid reaction. It contains hydrochloric 
acid and mucus. It is secreted by the peptic glands, situ- 
ated in the mucous coat of the stomach, by the glands that 
secrete hydrochloric acid, and bv mucous follicles. The 
different glands secrete the different constituents, all being 
mixed together to form gastric juice. 
Mechanism of Secretion. The peptic and the hydro- 
chloric acid glands are very similar in their microscopic 
anatomy. They are racemose glands, and in the cellular 
or lobular portion are lined with spheroidal epithelium. 
The ducts are lined with columnar epithelium. The mu- 
cous follicles are lined throughout with columpar epithe- 
lium, and are mostly situated about the pyloric end of the 
stomach. 
Function. The action of the gastric juice is upon the 
proteids. The product of its digestion is peptone. There 
is a small by-product which is called parapeptone. The 
gastric juice dissolves the envelope in which is held the 
fats, and it acts upon the fibrins, albumins, and gelatins 
by a disintegrating process. The substances swell up, and 
are reduced to a thin, pultaceous mass. Hydrochloric acid 
is necessary to its proper function, and to the presence 20 
PULTE COLLEGE PRIZE PAPER. 
of this principle is due the fact that gastric juice is nor- 
mally acid in its reaction. 
The active principle is pepsin. 
C. Pancreatic Juice. 
Description. Pancreatic juice is the digestive factor. 
It is similar to the salivary secretion in that its reaction is 
alkaline. It is viscid and translucent. 
Mechanism of Secretion. The pancreatic juice is secreted 
by the pancreas. This is a long, narrow organ, situated 
below and behind the stomach. It extends from the right 
to the left hypochondriac region, completely across the epi- 
gastric. It is composed of lobes. The secreting sacs, or 
terminations of the divisions of the ducts, are lined at the 
base with demilune cells; on these are the true gland cells. 
The ducts are lined with columnar epithelium. The 
small ducts join together, and form two: one that is large 
and opens into the duodenum, in company with the bile 
duct; and one that is smaller, and opens a little above 
this, which Bernard alone has found. 
Function. The pancreatic fluid acts on all the food that 
has not been digested by either the saliva or gastric juice. 
It emulsifies the fats. 
The active principle is trypsin. 21 
PHYSIOLOG Y A AD HISTOl. OG Y. 
V. 
In the Digestive Process, describe the Sucessive 
Stages by which the Food finally enters the 
Blood. 
The food, after being properly digested, enters the 
blood by some process of absorption. 
In the stomach the water and more fluid portions of the 
food are taken up by the capillaries, and enter directly into 
the venous circulation. 
In the intestines are found the villi. These contain lac- 
teals and capillary blood-vessels. The chief office of the 
lacteals is to absorb the fats; but during active digestion 
they are found to contain other substances. The lacteals 
convey their contents to the receptaculum chyli, and thence 
the thoracic duct carries it to the venous blood. The capil- 
lary blood-vessels in the villi take up the fluid, which, after 
absorption, is known as chyle. These capillaries pour this 
into the portal vein. 
Absorption takes place from the mouth to the anus, 
the degree being different in different parts of the aliment- 
ary canal, the ‘process always the same. 22 
PULTE COLLEGE PRIZE PAPER. 
VI. 
Give the Relation of the Nervous System to the 
Glycogenic Function of the Liver. 
The relation of the nervous system to the glycogenic 
function of the liver is not clearly known. It is intimate, 
however. The controlling influence seems to be centered 
in the floor of the fourth ventricle; for if this is punc- 
tured, artificial diabetes will result. The impulse is sent to 
the liver by other nerves than the pneumogastric ; for even 
if these are severed the glycogenic function, though sus- 
pended for a time, again becomes normal. The connection 
of the sympathetic system is not known. 23 
PH YSIOL OGY AND HIS TOLOG Y. 
VII. 
Give the Physiological Anatomy of the Kidney, 
and the Mechanism of the Secretion and Ex- 
cretion of Urine. 
A. Physiological Anatomy 
The kidneys are situated in the lumbar region, and 
are oblong, symmetrical bodies. They are inclosed in a 
coat of adipose tissue, inside of which is their proper cov- 
ering, the fibrous capsule. 
The fibrous capsule surrounds the kidney, and is contin- 
uous with the fibrous covering of the pelvis and ureters. It 
sends trabecuke into the cortical substance of the kidney. 
The kidney is composed of a cortical and a medullary 
substance. 
The cortical substance is granular. It occupies the exte- 
rior portion of the organ to the general depth of one-sixth 
of an inch, and sends down prolongations into the medul- 
lary substance. The cortical substance contains granular 
matter, Malpighian bodies, capillary plexuses of blood- 
vessels, convoluted uriniferous tubules, and the columns 
of Bertin. 
The medullary substance is found interior to this cortical 
layer, and is sometimes called the pyramidal substance, 
being composed of the pyramids of Malpighi. 
Blood Supply. The renal artery enters at the hilum, 
and, after dividing, passes forward toward the cortical sub- 
stance. The divided arteries continue to follow the same 24 
PULTE COLLEGE PRIZE PAPER. 
direction until they reach the bases of the pyramids, on 
which they form an anastamosing plexus. From this plexus 
branches are given off; those on the convex side extend out 
into the cortical substance, and each ramification becomes 
the afferent vessel of a Malpighian body, and after entering 
the body breaks up into minute branches, which form a 
dense convolution known as the glomerulus. The branches 
toward the concavity of the base of the pyramid pass back- 
ward toward the liiluin, and terminate in the capillaries of 
the pyramidal substance. These are called the arteriolse rectse. 
The veins originate in three ways,—from stellated rad- 
icles near the external surface of the cortical substance; 
from the capillary plexus about the convoluted tubes; and 
from the capillary plexus, in which the arteriolse rectse 
terminate. 
Malpighian Body. This is composed of an afferent and 
and an efferent vessel, forming a capillary plexus, without 
anastomosis, within the terminal expansion of a uriniferous 
tubule, the capsule of Muller. 
Tubidi Uriniferi. These are tubes beginning in the 
capsule of Muller, and extending to the calices. They are 
convoluted in the cortical substance; on reaching the bor- 
der of the medullary substance they become less so, and 
much narrower, and dip down into the pyramids, returning 
again to the cortical substance. Throughout this part of 
their course they are called the looped tubes of Henle. 
They again enter the pyramids of Malpighi, and their course 
is now more directly toward the pelvis. Several of them join 
together, forming larger tubes. In this part of their course 
they are called tubuli recti uriniferi, or the strait tubes of 
Bellini. 
Pyramids of Malpighi. These are the large pyramids 
of the medullary substance, and are composed of lesser 
pyramids, called pyramids of Ferreiu. PH YSIOL O GY AND HIS POL OGY. 
25 
Pyramids of Ferrein. These are collections of urinifer- 
ous strait tubes, about a hundred in each. 
Calrnes. These are little openings into which the apices 
of the pyramids are received. 
Infundibula. These are the short, funnel-shaped tubes 
into which the calices open. 
Hilus. This is the gateway of the kidney. 
Pelvis. This is the expansion of the ureter, and into it 
the infundibula open. 
Epithelium. The cells lining the strait tubes are polyg- 
onal in shape. It is supposed that those in the convoluted 
portion of the tubules are true gland cells, and that the 
capsule of Muller is lined with pavement epithelium. 
B. Mechanism of Secretion. 
The secretion of urine takes place in the Malpighian 
body and convoluted uriuiferous tubes. The watery ele- 
ments are principally separated in the glomerulus; the other 
constituents in the tubes, from the blood in the capillaries 
that surround them. The separation in the Malpighian 
body is effected mainly by pressure; that in the tubes, by 
the action of the true gland cell. The efferent vessel, after 
leaving the Malpighian body, is about one-half the size of 
the afferent. It still contains matter that is excrementi- 
tious; so its course is directed toward the convoluted tubes, 
and it forms a plexus about them to allow this waste matter 
to be extracted from the blood. When the renal vein is 
finally formed, it contains the purest blood in the body. 26 
PULTE COLLEGE PRIZE PAPER. 
VIII. 
Give the Mechanism of Respiration, and the 
Means by which Oxygen is conveyed to the 
Tissues. 
Respiration is of three kinds—pulmonary, cutaneous, 
and muscular. 
A. Mechanism of Pulmonary Respiration. 
Inspiration. The act of inspiration is performed by the 
muscles of inspiration, working in concert with those muscles 
that open the rima glottidis. In inspiration the rima glot- 
tidis is opened, and the walls of the thorax are extended. 
This extension of the walls causes a tendency to a vacuum, 
and the air rushes in to fill it. The muscles of inspiration 
are the diaphragm, the scaleni, the external intercostals, and 
the levators of the ribs, with accessory muscles, which are 
the serratus posticus superior, the sterno-cleido-mastoideus, 
the pectoralis major and minor, the serratus magnus, and the 
levator anguli scapulae. 
Expiration. The act of expiration is performed by the 
muscles of expiration and by the contraction of the tra- 
cheales muscles and of the elastic fibers found in the walls 
of the air-cells. The expiratory act is more passive than 
the inspiratory, and occupies about one-fourth the time of 
respiration. The muscles of expiration are the triangularis 
sterni, the sacro-lumbalis, the external and internal abdom- 
inal oblique, the transversal is, the infra-costales, and the in- 
ternal intercostals. 27 
PHYSIOLOGY AND HISTOLOGY. 
B. Means by which Oxygen is conveyed to the 
Tissues. 
Oxygen rushes in with the air when the lungs are filled. 
By the law of diffusion of gases, it rapidly passes through 
the air already in the lungs, and is brought in apposition 
with the membrane which lies between it, and the blood 
charged with carbonic acid gas. 
The interposition of the membrane favors diffusion. 
The oxygen passes in, and the carbon di-oxide out, still by 
the law of diffusion. The oxygen now enters into chemical 
union with the hemaglobin of the red corpuscle, forming 
oxy-hemaglobiu, and then this servant of the cells, the red 
corpuscle, carries the oxygen to the capillaries; here, the 
tissues having a greater affinity for the oxygen than has 
the hemaglobin, it enters their structure, and leaves the 
corpuscle, the carbon di-oxide being taken back to the lungs 
in exchange for the oxygen left with the tissues. 28 
PULTE COLLEGE PRIZE PAPER. 
IX. 
Give the Mechanism of a Continuous Flow of 
Blood in the Veins, and the Causes of a Sys- 
temic Venous Pulse. 
The three factors of a continuous flow of blood in the 
veins are the vis a tergo, or action of the heart, the overdis- 
tension of the arteries, and the peripheral resistance of the 
capillaries. When these three factors bear a normal rela- 
tion to each other, the stream of blood flows continuously 
in the veins. When any one of them is disturbed without 
a proper compensation in another, a venous pulse is the 
result. 
The First Factor. If the defect is either in the valves 
of the heart or in the stroke, there will not be sufficient 
force to overdistend the arteries. The impulse will be trans- 
mitted on through the capillaries into the veins, for the 
arteries are then, practically, inelastic tubes, and exert no 
modifying influence. 
The Second Fader.. If the weakness is in the coats of 
the artery, even though there be a sufficient heart-impulse, 
the elasticity of the arteries not being great enough to modu- 
late it, it will still propagate itself through the capillaries 
into the veins. PH YSIOLOG Y AND HISTOLOG Y. 
29 
The Third Factor. If the peripheral resistance of the 
capillaries is lessened sufficiently, as when their walls are 
dilated from any nervous cause, the arteries will not be over- 
distended, and the impulse will continue on through the 
whole circulation. 30 
PULTE COLLEGE PRIZE PAPER. 
X. 
Describe fully a Nerve, and give its Physiological 
Properties. 
A. Description. 
A nerve is a conductor of impulses and impressions. 
It is composed of one or more bundles of nerve fibers, 
held together by an investing sheath. 
Nerve fibers are of three kinds,—the medullated, the 
non-medullated, and the gelatinous. 
The Medullated Fibers are those which contain, in addi- 
tion to the axis-cylinder, a surrounding envelope of med- 
ullary substance, called the white substance of Schwann. 
This is in turn surrounded by the sheath of Schwann, 
a homogeneous membrane containing oval nuclei longi- 
tudinally arranged. In this sheath are contractions, the 
striae of Frommann, but they do not extend to the axis- 
cylinder. 
The Non-medullated Fibers are those which are of the 
same structure as the foregoing, except they do not contain 
medullated substance. They are found at the origin and at 
the peripheral extremities of the nerves generally. 
The Gelatinous Fibers, or fibers of Remak, are gray 
in color, of a flattened shape, and contain oval nuclei. 
They are not abundantly found. More are present in the 
sympathetic than in the cerebro-spinal system. They are 
most numerous in foetal life, and are present in regenerating 31 
PH YSIOL O GY AND HIS TOL O G Y. 
nerve tissue. They have been denied a classification as 
nerve fiber by some authors, and have been called simply 
connective tissue. Others have not regarded them as dis- 
tinctive nerve fibers, but have considered them to be unde- 
veloped or rudimentary fibers of the medullated or non- 
medullated variety. 
The axis-cylinder seems to be the part of the nerve essen- 
tial to its proper function, as it is constant from the origin 
to the termination. It is marked by longitudinal striations, 
which are thought, by some writers, to indicate a fibrillated 
structure. 
The nerve fibers are bound together by the perinevre 
into primitive bundles or funiculi. These bundles are 
again gathered together, and held by the perineurium. 
This constitutes a nerve, although the smaller nerves con- 
tain sometimes but one funiculus. Besides the nerve fibers 
and sheaths, each nerve contains accessory anatomical ele- 
ments ; as, blood-vessels, probably lymphatics, connective 
tissue, and nervi nervorum. 
Nerve fibers neither branch nor divide, but continue 
uninterruptedly from center to periphery. A fiber from one 
nerve will cross to another, thus assisting in co-ordination.' 
The nerves of the cerebro-spinal system originate in the 
brain from different parts of its structure; in the spinal 
column by the anterior and posterior roots, the motor, 
and co-ordinating and sensory, from the spinal cord. The 
sympathetic system is a chain of nerves and ganglia con- 
nected with the cerebro-spinal system, and dependent 
upon it. 
Nerves terminate, generally, by gradually becoming less 
in diameter, until they are lost to the microscopic eye. 
They terminate specially in the terminal plates of the mus- 
cles, the taste bulbs, the tactile corpuscles, and the corpuscles 32 
PULTE COLLEGE PRIZE PAPER. 
B. P HYSIOLOGICAL PROPERTIES. 
The axis-cylinder conducts, the other parts are accessory. 
The nerves are carriers, both from the center to the periph- 
ery and in the opposite direction. The efferent fibers bear 
motor impulses from the brain. The afferent fibers convey 
sensory impressions to the brain. There is no known differ- 
ence between the afferent and efferent nerves in anatomical 
structure. 
Nerves possess the property of irritability to a marked 
degree. They can be stimulated by electricity, which re- 
sembles nerve force. They are capable of being regen- 
erated. They are conductors of nerve force or vitality. 
That they are the connecting link between the brain and 
the outside world is known ; but how the brain and the 
governing mind are united, neither the physiologist nor the 
npcroscopist has revealed.