NationalLibraryOfScotland/medical-history-of-british-india huggingface dataset:
CHAPTER
VIII.
THE NERVOUS SYSTEM AND SPECIAL ORGANS.
The nervous system.—The . nervous system consists of (a) the
brain, (b) the spinal cord, (c) the nerves.
(a) The brain is contained within the cranial cavity. It is
the organ that regulates every vital process in the
body ; it is the seat of the will and intelligence ; it
controls all motion, appreciates and locates sensation,
and its activity is exhibited in part by what is termed
consciousness.
(b) The spinal cord is contained within the vertebral canal,
and is in relation to the brain what a local post office
is to the general post office. It only controls certain
functions of the body and even in those is itself
controlled by the brain.
(c) The nerves are merely conducting media between
sensitive surfaces or organs and the brain and cord.
They are the telegraph wires which convey the
messages emanating from the brain or spinal cord,
the outcome of which may be seen in a variety of
ways, such as size of the pupil, degree of redness of
mucous membranes, the activity in the secretion of a
gland, the movement of a muscle or a limb, the voiding
of excreta, etc.
Eye.—The optic nerve is responsible for the sense of vision
and is unusually small in the elephant, the reason for which is
evident when one considers the small size of this organ and the
muscles required to move it. The eye resembles that of other animals.
The visible portion consists of a transparent convex disc like a
watch glass called the cornea, behind which is the coloured portion
of the eye (iris) which is usually brown, and centrally the pupil
which is jet black and round. Vision is acute, but the animal is
greatly handicapped in making use of this sense to a degree equal
to that of most animals by virtue of the shortness of its neck which
will not permit of the head being turned sideways sufficiently to see
objects in its rear: therefore the only way this can be effected is by
a movement of the body, and this is exemplified by watching an
elephant walking when it is suspicious of something in its rear.
THE NERVOUS SYSTEM AND SPECIAL ORGANS.
99
It will be seen to alternately move the body from side to side in
order to see what is occurring behind instead of walking straight
forwards. However, the limited field of vision is fully compensated
for by the extreme acuteness of smell and perhaps partially by its
keen hearing. As is the lease with many animals, in addition to an
upper and lower eyelid there is a membranous fold placed at the
inner corner of the eye and beneath the lids which is capable of
being moved outwards over a considerable portion of the eyeball :
this is called the nictitating membrane, the haw (of horses), and
by some authors the " third eyelid." This outward movement is
effected by a retraction of the eyeball which displaces some fat
behind the orbit and so mechanically thrusts the lid forwards.
Lachrymal apparatus.—The
eyelids furnished with eyelashes
blink every few seconds and a slight watery discharge flows over
the cheek. There is no true lachrymal (tear) gland, but this is
replaced by a gland situated on the inner side of the orbit called
the Harderian gland, which pours its secretion on to the third
eyelid , whence the tears so produced fall on to the face, there
being no apparatus to convey them into the nose such as exists
in most animals.
The diseases of the organs of sight do not vary from those of
other animals.
The following departures from the above indicate present or
past disease, namely—
(a) Frequent blinking.
(b) Abnormal discharge, either watery or turbid.
(c) Haziness or opalescence of the pupil.
(d) Opalescence of the cornea.
(e) Undue redness seen when the lids are separated.
(f) Blindness, partial or complete.
Ear.—There
is nothing of special interest to note except as
previously mentioned as an indication of age (see page 2).
The temporal glands.—These well-known glands, called kapool
by natives of India, are two in number and are situated one on
each side about midway between the eye and ear-hole. Their
ducts open on the skin in this region. The glands are usually
inactive. They are analogous to the glands in deer which open
into pits seen under the eyes and to the gland on the back of the
head of camels.
CHAPTER IX.
ELEMENTARY PHYSIOLOGY.
The body is made up of various parts or organs, each with a
separate action or function.
Organs again are composed of certain definite structures or
tissues differing widely from one another, not only in their physical
characters and appearance but also in their functions.
All tissues are composed of certain similar elements more or
less modified, which are called cells, and the functions of the different
tissues are due to the activities of their cells.
The cell is a minute mass of living substance or protoplasm, in
which is situated a more or less well-defined body, the nucleus.
These are the essential parts of a cell. Each little cell possesses
the power of assimilating particles of food brought to it, of movement
and of reproduction.
From the protoplasm of the cells the various tissues of the body—
bone, muscle, nerve, etc.—are formed. The animal body is originally
a single cell, and from this, by division, a mass of simple cells is
produced, which become arranged in the embryo into three layers—
an outer, a middle and an inner—and from these three layers the
different sets of tissues develop.
Tissues are divided into two classes:—
(a) The vegetative tissues which support, bind together,
protect and nourish the body : as examples of such
tissues we have bone tissue, fibrous tissue of ligaments,
and tendons, skin and gland tissue.
(b) The master tissues of the body, muscle and nerve.
A detailed description of these tissues is unnecessary here ; it
will only be observed, however, for the benefit of the lay reader
that there are two kinds of muscle tissue : one under the control of
the will and therefore called voluntary muscle, and the other
not so controlled and known as involuntary muscle, such as
for instance, the muscles of the intestine. Voluntary muscles are
actuated by nerve impulses from the central nervous system.
Nerves pass from the skin and various tissues inwards towards the
brain, carrying impressions to that organ, and from the brain nerves
pass outwards to the muscles and tissues, stimulating them to
action. The brain itself is nothing more than a collection of nerve:
ELEMENTARY PHYSIOLOGY.
101
cells. As examples of the co-ordination between muscle and. nerve,
we have only to observe the rapidity with which an animal, if
pricked in the leg, lifts that member almost immediately, and again
there is the well-known saying, "his mouth watered at the sight of
so many good things," as showing the stimulation of the salivary
glands by the sight of food.
Nutrition
of the tissues : blood and lymph.—The
blood
carries the necessary nourishment to the tissues and receives their
waste products. It is however enclosed in a system of vessels
and does not come into direct relationship with the cells.
Outside the blood vessels and bathing the cells is the lymph.
Lymph may be looked upon as the middleman between the blood
and the tissues ; it carries nourishment from the blood to the tissues,
and receives in return the waste products of the tissues to be
carried back to the blood.
Blood is composed of a clear fluid (plasma) in which is
suspended millions of small discoid particles—the blood corpuscles
or blood cells. These blood cells are of two different kinds and are
generally spoken of as red cells and white cells. The colour of the
blood is due to these red cells.
When blood is withdrawn from living vessels, it clots ; the red
cells being the heaviest, sink to the bottom ; the white cells form the
next layer, while above all little drops of a clear amber-coloured
fluid make their appearance which, running together, form the
serum. Clotting is due to changes in the plasma as this fluid
coagulates in the absence of corpuscles.
Serum is not plasma in that it does not contain the protein
fibrinogen, but otherwise it resembles plasma both in appearance and
composition. It contains various proteins, the most important being
serum albumen, the amount of which varies according to the condition
of the animal.
The other organic substances in scrum may be classified as—
(i) Substances to be used by the tissues :—
(a) Glucose, a carbohydrate which is usually in larger
amount in blood going to muscles than in that
coming from muscles. This difference is more
marked when the muscles are active.
(b) Fats, which occur in varying amounts depending on
the nature of the food.
(ii) Substances given off by the tissues, i.e., the waste
products of tissue metabolism. The principal of these
is urea which occurs constantly in minute quantities.
The principal inorganic constituents of serum are the chloride,
102
A TREATISE ON ELEPHANTS.
carbonate and phosphate of sodium. Calcium, potassium and
magnesium also occur in small amounts.
White cells are of different varieties. Their most important
function is the removal of useless and effete tissues, dead micro-
organisms, etc. They may be looked upon as the scavengers of the
body.
Red cells are circular biconcave discs devoid of a nucleus as a
rule. Their colour is due to an iron-containing substance called
haemoglobin. Haemoglobin possesses the property of taking up
oxygen from the air and of giving it up to the tissues ; it thus acts
as the middleman between the air and the tissues. In certain
diseases the number of red cells or the amount of haemoglobin in
the red cells is reduced, and the animal is said to be anaemic.
Lymph.—Lymph
is the fluid which acts the part of middleman
between the blood and the tissues. All the tissue spaces are filled
by it, and every little cell is bathed by it. The tissue spaces open
into lymph vessels through which the lymph flows to the lymph
glands and thence back to the blood. In composition, lymph
resembles somewhat the blood plasma, but it contains only a few
white cells which are small in size and are known as lymph cells.
Lymph is a straw-coloured fluid, but in the lymphatic vessel
coming from the digestive canal after a meal it has a milky appearance,
due to the presence of fats in a very fine state of division which have
been absorbed from the intestine.
Lymph is derived partly from the blood and partly from the
tissues.
Circulation.—The
means by which the blood and lymph are
distributed to the tissues consists of a central force pump, the heart,
and a series of tubes, the arteries, which lead to all parts of the
body and terminate in innumerable fine tubules, called capillaries, in
the substance of the tissues. From these capillaries a certain
proportion of the blood constituents escape into the spaces between
the cells as lymph. This lymph is carried away in a series of
lymph vessels passing through the various tissues and organs to the
lymph glands, and from there back to the heart by way of the veins.
During its passage through the tissues the lymph is deprived of
much of its nutrient material, receiving in return the waste products
of tissue metabolism. The remainder of the blood, which has not
passed out of the capillaries as lymph, has thus been deprived of
some of its nutrient material ; this is made up for by a part of the
blood being sent through the walls of the stomach and intestine
where nutrient material from the food is taken up by the blood
returning to the heart. In addition to this nutrient material the
blood returning to the heart contains waste products, the result of
ELEMENTARY PHYSIOLOGY.
103
tissue metabolism. These waste materials are partly got rid of by
a portion of the blood being sent through the liver and kidneys.
The blood returns to the right side of the heart (the right auricle),
and from here it is pumped by the right ventricle through the lungs,
where it gets rid of the carbonic acid gas and other effete material
received from the tissues and takes up a fresh supply of oxygen.
From the lungs it returns to the left side of the heart (left auricle)
to be again pumped through the body by the left ventricle.
CHAPTER X.
ELEMENTARY PHYSIOLOGY—continued.
Food and digestion.—The
principal use of food is to supply
energy to the body, the muscles of the body being constantly active
or continually liberating energy by breaking down the complex
proteins, carbohydrates and fats, and therefore fresh supplies of
these are necessary to prevent the body living on its own material
and wasting away.
Again during growth, the material from which the body is built
up must be supplied by the food, so that a suitable food must be
able to yield the necessary amount of energy and also supply the
materials necessary for growth and repair.
Before food can be utilised by the body it must be broken down
to its simplest form and rendered soluble, and the process of
preparing the food for absorption is called digestion.
Before considering the process of digestion some idea of the
composition of food must be given. Foodstuffs are classified into
those not yielding energy and those that do yield energy—the former
acting chiefly as solvents, e.g., water and the inorganic salts. The
foodstuffs yielding energy are complex combinations of the chemical
elements—carbon, hydrogen and oxygen, with or without nitrogen,
sulphur, phosphorus and iron—that is to say, they are of the same
nature as the materials found on the analysis of dead protoplasm.
The energy-yielding foodstuffs are further subdivided into nitrogen-
containing compounds and non-nitrogen-containing compounds.
The proteins belong to the former, and the carbohydrates and fats
to the latter. The proteins are important in that they are the only
source of the nitrogen and sulphur necessary for the construction
and repair of living tissues ; they are therefore the essential organic
constituents of the food. Proteins leave the body as carbonic acid,
water and urea.
The difference between the carbohydrates and fats is that in the
former the oxygen and hydrogen exist in the same proportion as in
water ; carbohydrates and fats leave the body as carbonic acid and
water.
Digestion.—In the elephant the food is grasped by the trunk
and placed in the mouth where, by the act of chewing, it is
thoroughly broken up and mixed with the saliva.
ELEMENTARY PHYSIOLOGY.
105
Saliva is a turbid frothy fluid secreted by the salivary glands
and various smaller glands in the lining membrane of the mouth.
The active constituent of saliva is a ferment called ptyalin. The
functions of saliva are two-fold :—
(1) Mechanical, to moisten the mouth and gullet, and so assist
in chewing and swallowing.
(2) Chemical, by reason of the ferment ptyalin to convert the
starchy matters (carbohydrates) into sugars.
The flow of saliva is stimulated by the act of chewing and by
the sight of food.
The food having been masticated is collected on the surface of
the tongue by the action of various muscles ; the tongue is pressed
against the palate and the bolus of food pressed backwards to the
root of the tongue where it passes between the pillars of the fauces
into the pharynx. The muscles of the pharynx contract and the
food is forced into the gullet, which, by a slow wave-like contraction,
sends the food to the stomach. During the passage of the food
over the larynx the posterior cartilages are approximated, and the
tip of the anterior cartilage applied to them forming a triradiate
fissure through which food cannot pass. Before food reaches the
stomach this organ is collapsed ; the mucous membrane is pale in
colour and thrown into ridges ; there is little movement and the
secretion is scanty, only a little mucus being found covering the lining
membrane. When food arrives, however, the blood vessels dilate, a
secretion is poured out and churning movements begin.
The gastric juice is secreted by glands situated in the mucous
membrane of the stomach. It is a clear watery fluid containing
hydrochloric acid, some organic salts and two ferments, one a protein-
splitting ferment, pepsin, and the other a milk-curdling ferment,
rennin. The pepsin acts on the proteins, converting them eventually
into their simplest form, peptones.
On fats the gastric juice has no action further than dissolving
and digesting their protein covering and thus setting them free.
The gastric juice is also antiseptic by reason of the free
hydrochloric acid it contains.
After gastric digestion has progressed for some time the partly
digested food is passed on to the intestine where the process is
completed. The stomach plays a very small part in the absorption
of food, sugar and peptones only being taken up from it.
In the intestine the food, which is now in a semi-fluid puitaceous
condition and called chyme, meets with three different secretions,
the bile, pancreatic juice and intestinal secretion.
(1) Bile is the secretion of the liver, and its function is to act
as a solvent of fats and assist in their digestion and absorption.
I06
A TREATISE ON ELEPHANTS.
(2) Pancreatic juice is the secretion of the pancreas ; it is a
clear slimy fluid containing two ferments, one a protein-splitting
ferment, which completes the work begun in the stomach, and the
other, a starch-splitting ferment similar in its action to ptyalin but
more powerful.
There is also a fat-splitting ferment present which breaks up the
fats into their component parts and aids in their absorption.
(3) The intestinal juice is a pale yellow-coloured fluid secreted
by various glands in the lining membrane of the intestine, and
containing a ferment which assists the pancreatic juice in various
ways but principally by splitting peptones and many other proteins
into still simpler bodies.
Movements of the intestine.—The
intestine being composed of
involuntary muscle tissue, its movements are of the wave-like variety
and assist in passing the food along.
During its passage along the intestine the proteins, fats and
carbohydrates are absorbed, and what remains is thrown out as
fæces. The food absorbed is carried along by the blood stream
and distributed to the tissues as we have seen. It may be used
immediately as a source of energy for the production of work and
heat and for the repair of tissues, or it may be stored in the body
for future use ; in most animals this storage takes place in the fatty
tissues, so that when the usual supply of food is cut off for any
reason, the animal uses its own stored materials and tissues. This
is shown by the animal losing weight. In starvation, etc., the first
tissues to go are always the fatty tissues.
Respiration.—All
animals require oxygen ; in mammalians this
is taken from the atmospheric air, and the process is called
respiration. The process of respiration consists of two parts :—
(1) The passage of air into and out of the air cells of the lungs.
(2) The interchange of gases between the air in the air cells
and the blood in the lung capillaries.
The atmospheric air is composed of two gases principally, namely
oxygen and nitrogen, in the proportion of 21 parts of the former to
79 parts of the latter: nitrogen is incapable of supporting life and
its use seems to be to dilute the oxygen.
(1) Passage of air into and out of the lungs—Is brought about
by the movements of expiration and inspiration.
The act of inspiration is a muscular act brought about by the
muscles of the chest, the resting position of the chest being that of
expiration. Ordinary expiration is mainly a passive act, being
simply the return of the chest to the position of rest, but sometimes
voluntarily or involuntarily expiration may be forced and in this
case the act is partly due to various muscles. The chief of these
ELEMENTARY PHYSIOLOGY.
107
are the abdominal muscles which compress the viscera, pushing them
upwards and thus press the diaphragm further up into the chest.
At the same time they pull back the ribs and thus decrease the size
of the chest from side to side.
Special respiratory movements, i.e., coughing, sighing and
yawning—
(a) Coughing is due to irritation of the respiratory tract and
is produced by a forced inspiration followed by a strong
effort at expiration, during which the glottis (opening of
larynx) is closed but is forced open by the current of
expired air.
(b) Sighing and yawning are deep involuntary inspirations.
They accelerate the circulation of the blood when from
any reason this becomes less active.
(2) The interchange of gases between the air in the air cells
and the blood.—This is effected partly by diffusion and partly by
the activity of the air cells lining the vesicles of the lung. Carbonic
acid gas and water are exchanged for oxygen, which is in turn
exchanged for carbonic acid, etc., from the tissues.
Excretion
of matter from
the body.—We
have already
seen that the waste and useless material in the food, together
with a certain quantity of water, is got rid of by the bowels.
We have also seen that a certain amount of the products of
tissue metabolism is excreted by the lungs ; but there is still a
certain amount of waste material which has not been accounted for,
i.e., the remainder of the water and the waste nitrogen of the
body ; these are chiefly eliminated by the urine which is secreted by
the kidneys. The kidneys may be roughly described as a collection
of cells arranged more or less in the form of little tubules between
which capillaries run. Each tubule commences as a small sac
surrounding a tuft of vessels ; these little tubules collect and run
together until at last we find in the centre of the kidney a small
fan-shaped cavity which leads into the duct of the kidney—the
ureter. As the blood passes along through the kidney, the cells of
the little saccules and tubules extract from it a certain amount of
water and waste solids, the most important being urea, which is the
form in which about 80 per cent. of the waste nitrogen leaves the
body. As it is secreted, or rather excreted, the urine passes down
the ureters to the bladder, and when a certain amount has collected,
the bladder contracts and it is discharged.
[Facing page 109.
PLATE VII.
ELEPHANT WORKING IN JUNGLE.
PART III.
Medicines and their Administration. Formulæ.
CHAPTER I.
PREPARATION AND MODE OF ADMINISTRATION.
As already pointed out, Veterinary Surgeons rarely have an oppor-
tunity of treating elephants, and as owners usually do not know
much about their ailments, the treatment is invariably left to the
mahouts. These men employ a multiplicity of drugs to make
up their formulae or mussauls ; they are purchased in the bazaar
and I have frequently seen them ; excepting the curry-stuffs, the
vegetable drugs are usually old, mildewed and inert, and the minerals
impure.
The expense incurred by the purchase of reliable drugs from a
chemist, where purity, freshness and uniformity in strength are guar-
anteed, would at the end of a year be far less than the cost of the
ordinary expensive mussauls so frequently indented for. A good
many of the curry-stuffs supposed to enter into them often find their
way to the mahout's quarters. Domestic elephants must carry a
special heat-generating apparatus in their interiors, as gurmi or heat
seems to be the most prevalent ailment amongst them and the
amount of cooling mussauls required is truly surprising.
No drug is known to have an emetic action on this animal.
Gilchrist mentions that " tartar emetic has been given in 2-oz.
doses morning and evening till half a pound was taken but no-
emetic or other obvious medicinal effect followed."
Mahouts are strongly averse to the administration of purgatives ;
in fact they never intentionally purge an animal, though such drugs
as croton seeds, aloes, enter into the composition of many of their
mussauls.
Doses.—The question of the amount of a drug to be given is a
matter of some difficulty, seeing how very rare it is that opportunities
offer for trying experiments on these valuable creatures. There can
be little doubt however that, misled by the size of the animal, drugs
have been administered in what appear as excessively large doses
and not always free from risks; perhaps bazaar drugs were used,