NationalLibraryOfScotland/medical-history-of-british-india huggingface dataset:
MUCOUS AND SEROUS MEMBRANES.
75
It is furnished with blood vessels, nerves, etc. In health it is-
of a delicate pink colour ; in fever and inflammations it becomes,
reddish, and the minute blood vessels are frequently injected ; when,
the liver is deranged they assume a yellowish tint; and in debility
and anæmia the membrane is usually pale and bloodless. In the
elephant the colour of the mucous membrane covering the mouth,
tongue and palate is easy to note ; sometimes that covering the
eye can also be seen, and this latter being of a highly delicate-
structure shows any changes in a marked manner.
SEROUS
MEMBRANE
Is a firm white membrane lining the closed cavities of the body,
i.e., those not communicating with the external air. The membrane
is reflected over the organs contained within these cavities. Its
duty being to protect and keep them in position also by means of a
very small quantity of lubricant fluid (serous fluid) which it secretes,
it permits the organs to glide freely over each other without injury.
In particular positions the membrane receives distinctive names:
that portion lining the thorax is called the pleura ; that lining the
abdominal cavity, the peritoneum ; while the portion which suspends
the bowel is known as the mesentery. In the elephant the peri¬
toneum is very thick, and there is a general absence of fat which
is usually to be found in most animals.
MUSCULAR
SYSTEM.
This system is remarkable, in that a large amount of tendinous
fibre runs through the muscles, making them very tough. About
the shoulders and buttocks the muscles are fleshy, but even here
there is a considerable admixture of tendinous fibre. The flesh is
much relished by Burmans, Shans and Karens.
CHAPTER III.
THE CHEST AND ORGANS OF RESPIRATION.
The thorax, or chest, is a large chamber bounded laterally by
the ribs and their muscles, above by the spine, below by the breast-
bone, and behind by an obliquely placed musculo-tendinous partition
which separates it from the abdominal cavity, and known as the
diaphragm or midriff. It contains the heart and respiratory organs
and is deep and narrow. From researches conducted in recent
years by M. Alfred Giard * and others it has been found that the
pleural cavity, although present in the young elephant, is obliterated
in the adult. This is a condition entirely different from what
occurs in most mammals in which the lungs, though lying in contact
with, have no actual attachment to the walls. This peculiarity is
adapted to his mode of life, which seldom subjects him to respiratory
emergencies, and his organization which does not necessitate rapid
blood oxygenation.
In the lungs the blood cells are furnished with oxygen, which
being circulated by means of the heart distribute it to the tissues
which build up the system. Oxygen is necessary to the life of those
tissues. To effect this charging of the blood cells with oxygen
breathing is constantly going on, and consists of two acts : the first
during which air is conveyed through the respiratory passages to the
lungs to purify the blood (inspiratory act), and the second during
which air with impure products generated in the system is thrown
out (expiratory act). During inspiration the chest expands and on
expiration it contracts. In health this double act is performed on
an average 12 to 16 times a minute.
The respiratory organs.—The respiratory tract consists of—
Nostrils.
Wind-pipe.
Nasal chambers in the skull.
Lungs.
Nose.—The nasal apparatus consists of certain structures which
serve to form two passages, whose function, is to conduct air from
without into the air chambers in the bones of the skull, and also to
* Comptes rendus des seances de l'Academie des Sciences, CXLIV, page 306,
11th February 1907, by M. Alfred Giard.
Comptes rendus des stances de l'Academie des Sciences, CXLIV, page 471,
4th March 1907.
Comptes rendus des stances de l'Academie des Sciences, CXLIV, page 318,
17th June 1907.
THE CHEST AND ORGANS OF RESPIRATION.
77
the back of the mouth, and so through the wind-pipe to the lungs.
These passages are lined throughout with mucous membrane, in the
uppermost part of which are lodged the nerves concerned in the
sense of. smell. It may conveniently be divided into two parts,
namely, the muscular portion or trunk, and the osseous or bony.
The muscular portion or trunk is a most remarkable appendage,
but is not peculiar to the elephant, as the tapir has a somewhat
similar organ. It is composed of an intricate arrangement of
muscles which furnish it with great flexibility, contractility, and
power, so that its uses are manifold. The animal is enabled to snap
off boughs, pull down saplings, pluck up bunches of grass and
herbs—in fact, on his trunk depends his life, since both food and
drink are ingested through its aid. He can employ it to lift and
drag light weights. An elephant will not use his trunk either for
offence, defence, or work where there is any probability of this
extremely sensitive and essential organ sustaining any injury, and this
is exemplified by the way in which he curls up the organ after the
manner of a watch-spring, and raises his head when in the act of
charging, and not free and uplifted as often represented in many
pictures.
At the extremity of the trunk the anterior part is developed into
a finger-like structure, which is capable of being approximated to the
posterior wall. By means of this process he is able to pick up
articles of small size, but not to the extent that he has been popularly
credited with. Its contractility is shown by his power of shortening
and lengthening this organ and, as will be again referred to on some
future page, this contractility, by causing a shrivelling of the trunk,
often serves as a valuable indication of ill-health. Again; it is
through the muscular character of its walls that he is able to dilate
the canals and increase their capacity during the act of suction.
This muscular mechanism is supplied by the seventh pair of nerves
which are unusually developed in this animal and hence accounts for
its power, varied and complicated mobility. The skin covering the
trunk is soft and pliable, and that in the posterior region is puckered
into a series of transverse ridges, giving it a permanent roughness
which materially aids in the tenacity of its grip. It is also the
medium through which this organ is endowed with one of its most
important uses, for it is in the deeper layers of the skin that the
elements of the sense of touch are lodged. It is supplied by the
fifth pair of nerves which are also unusually developed in the elephant
and accounts for its exquisite sensibility.
The canals are two in number and lie nearer to the front of the
organ. They are of about the same calibre throughout, and are
lined by mucous membrane. They are capable of a certain amount
78
A TREATISE ON ELEPHANTS.
of distension and, in addition to serving as conductors of air to the
lungs and air cells, are converted into temporary reservoirs in the
act of drinking. The end of the trunk during this act is placed in
the water, and by suction (an inspiratory effort) a quantity is drawn
up into the canals. The trunk when a sufficiency has been taken
up is withdrawn, and inserted far back into the mouth, where by an
expiratory effort the contents are expelled and swallowed or in the
act of bathing ejected over its body. It is highly improbable that
the mucous membrane lining these canals is in any way concerned
with the sense of smell.
Every one familiar with elephants must have observed the pecu¬
liar habit they have when heated of inserting the trunk into the
mouth and by suction withdrawing fluid which they squirt over the
body. Many theories have been advanced as to where this fluid is
accumulated : some investigators say that the stomach is the reservoir
and that the cell-like formation at one end (much exaggerated in the
drawing) can hold as much as ten gallons of water, and Dr. Harrison
found a muscle connecting the back of the wind-pipe with the forepart
of the gullet, one of the functions of which he thought might be to
raise the cardiac orifice of the stomach and so enable it to regurgitate
its contents into the gullet. (The muscle alluded to must have
been abnormal as I believe other anatomists have not found it.)
Others are of opinion that a special pouch at the back of the throat
(pharyngeal) is the reservoir. The point at present is not satisfac¬
torily settled ; but as Steel states, the " pouch " is capable of holding
a fair amount of fluid which may be supplemented by gradual
regurgitation from the stomach. The subject is a most interesting
one, and those desirous of obtaining full information should refer to
the excellent works of Steel, Sterndale, and Sanderson.
Selous in his book, "A Hunter's Wanderings in Africa," page
181, refers to this habit among African elephants.
Sounds.—A forcible blast of air blown through the trunk pro¬
duces the sound familiarly known as " trumpeting," and another
peculiar sound is also emitted through the agency of this organ.
This is referred to by Sanderson, and accurately likened by him, to
the sounds produced by rapidly doubling a large sheet of tin. This
authority says that " it is produced by rapping the end of the trunk
smartly on the ground, a current of air hitherto retained, being
sharply emitted through the trunk, as from a valve, at the moment
of impact." The sound is familiar to those who have indulged in
elephant shooting, and appears to be a note of warning on the
apprehension of danger.
Elephants make a variety of other sounds : for instance, during
the stillness of the night wild elephants may be heard making a
THE CHEST AND ORGANS OF RESPIRATION.
79
droning noise, which may be due either to pleasure or calling the
attention of stragglers to the herd. Again, when being loaded or
driven hard they may roar. This sound is produced by the throat,
the mouth being wide open and the trunk often uplifted.
Pleasure
may be indicated by the usual low squeaking through the trunk, as
is often heard when elephants have been separated during the day
and meet in the evening. A further well-known sound is the low
rumbling made in the throat expressive of want or anger; this in a
modified way is often made by calves when separated from their
mothers. The common sound of "prut, prut," which is often heard
when elephants are travelling, I think may indicate impatience.
When elephants desire to frighten anything such as dogs, etc., they
often blow through their trunks.
Vascularity.—This
organ is very richly supplied with blood-
vessels, and thus accounts for injuries being attended with copious
haemorrhage, which in fact may prove fatal.
The osseous or bony portion is so constructed as to form two
irregularly shaped chambers communicating in front with the canals
of the trunk, and behind with the mouth. In addition there is free
communication with the honeycomb-like pneumatic chambers (or
air sinuses) of the head already referred to. The chambers are
lined with mucous membrane in which are embedded the terminations
of the olfactory nerves, or nerves of smell, which, being unusually
well developed in the elephant, accounts for the acuteness of this
sense.
Larynx.—This
consists of a chamber opening below the base of
the tongue by which air is conducted down the trachea or wind-pipe
into the lungs. It contains the essentials in the production of voice.
Trachea and bronchi.—The
trachea or wind-pipe is a tube
composed of a series of cartilaginous rings, which rings are incom¬
plete behind. It divides into two tubes of smaller calibre called the
bronchi, which enter the lungs and ramify throughout their sub-
stance. These air passages are unusually long and narrow.
Lungs—Are two spongy organs, one on each side of the chest,
to the walls of which, as already remarked, and to the diaphragm,
they are intimately attached. The left can be readily distinguished
from the right by presenting no deep fissures in its contour.
Healthy lungs are of a delicate pink colour and should float in
water. If however the lungs be not examined till some time after
death, the lung on the side on which the carcass is lying will be
found blackish in colour owing to blood having gravitated into it.
The average weight of the lungs of four animals was 46 lbs.
The mucous membrane at the orifices of the trunk is a rich pink
colour and moist, with an occasional drip of clear fluid. Any
80
A TREATISE ON ELEPHANTS.
departure from those conditions may indicate disease of this tract,
and may be summed up as follows :—
(a) Undue redness of mucous membrane of trunk.
(b) Constant dripping of a clear or opaque yellowish fluid
from trunk.
(c) Soreness inside the trunk.
(d) Cough.
(e) Hurried or difficult breathing.
(f) Impaired movements of chest with compensatory increase
of movement of belly during breathing.
[Facing page 81.
PLATE VI.
EXTRACTING A HEAVY LOG.
CHAPTER IV.
THE CIRCULATORY SYSTEM.
The circulation of the blood is carried on by means of the heart,
arteries, capillaries, and veins.
Arteries.—The
arteries are the channels which convey blood
from the heart, distributing it over the system. If an artery be
pressed by the finger, an impulse or shock is felt, known as the
pulse. They aid in forcing the blood onwards by means of their
elastic walls, which are thicker than those of veins, and do not
collapse when empty.
Capillaries.—Capillaries
are the very minute channels which
allow certain portions of the blood to pass through their walls into
the surrounding tissues for their nourishment. They are the anas-
tamotic network of vessels whereby the terminations of the arteries
are continued to form the beginning of the initial branches of the
veins.
Veins.— Veins are the channels which carry blood back to the
heart.
The small veins unite to form main trunks which finally carry
the venous blood to the right auricle, from which it passes into the
right ventricle, and from thence through the artery of the lungs
(pulmonary, the opening of which is in the ventricle) to the lungs.
After oxygenation in the lungs it is conveyed to the left auricle,
then to the left ventricle into the aorta, a large artery, which
distributes the purified blood over the body.
Lymphatic.—The lymphatic system consists of a series of tubules,
the lymph vessels, and a number of glands. In the elephant the
lymphatic system is so poorly developed as to be almost non-existent.
There are few lymphatic vessels, and the lymphatic glands are few
and small in number. The main lymphatic vessel, the thoracic duct,
is extremely small, being not much larger than that in man. The
lymphatic vessels are for the purpose of carrying lymph from the
blood to the tissues.
The heart.—The heart is a hollow muscular organ consisting of
four chambers, situated within the chest and enclosed within a bag
(the pericardium).
The two upper chambers are called auricles; the lower two,
ventricles.
6
82
A TREATISE ON ELEPHANTS.
The orifices between the auricles and ventricles are guarded by
valves, as also is the entrance to the pulmonary artery and aorta.
What happens is roughly as follows. The blood pours into the
right and left auricles which when full contract, thus driving the
blood into the ventricles, which on filling, the valves shut off their
communication with the auricles ; the ventricles now contract, driving
the blood on the right side through the pulmonary artery to the
lungs for purification, and through the aorta on the left side for
distribution of the blood over the system; the valves close when the
vessels are filled, preventing a reflux into the Ventricles.
The elephant's heart is peculiar, in that its apex presents two
points instead of one like most mammals. This peculiarity is
however shared by certain whales, dugong, etc. Another peculiarity
is the fact that there are two large veins (anterior venæ cavæ) enter¬
ing the right auricle instead of one as in most other mammals, in
addition to the posterior vena cava. There is an absence of fat
about the organ. The heart beats from 46 to 50 times a minute.
Weight-average of three hearts, 24 lbs.
Pulse.—"The
impulse or shock caused by the overfilling of the
aorta during the ventricular systole (contraction of ventricles) is the
cause of the pulse."—(Ashby.)
In a healthy elephant when at rest, if the finger be applied to
an artery, the vessel will be found to expand between 46 and 50
times a minute ; a short increase or decrease may be quite normal.
Many things increase the frequency of the pulse rate—exercise,
fever, fear, age. In young animals it is faster than in aged beasts.
The pulse is a useful indication as to the state of the circulation ;
the character also has to be noted as it varies ; for instance, in debility
we often get a soft and frequent pulse; in some heart affections an
intermittent pulse, that is there is an occasional loss of a beat which
may be regular, e.g., every fifth or sixth beat, or irregular.
The most suitable place for taking the pulse is at the back and
root of the ears, where will be distinctly seen a branch of an artery
running over the cartilaginous root of the ear and subsequently
ramifying on its surface. The pulsation will readily be felt by
applying the finger. It is not however so easy a matter to deter¬
mine the exact number of pulsations, as the animal approached by
a stranger, and especially if in the recumbent position, will not easily
be made to remain sufficiently quiet for the required time. The
better way is to cause an intelligent mahout to count aloud the
pulsations while the animal is standing and when the circulatory
system is not disturbed by fear or exertion on the part of the animal.
In every establishment one or two mahouts should be taught to take
the pulse accurately.
CHAPTER V.
THE DIGESTIVE SYSTEM.
The abdominal cavity or belly is of large size, the nature of
the food requiring voluminous intestines. The cavity is bounded
in front by the diaphragm or midriff, which separates it from the
chest cavity; posteriorly by the pelvis ; above by the back-
bone ; laterally by the ribs and their muscles, and below by the
abdominal muscles. The cavity contains a portion of the gullet, the
stomach, intestines, liver, spleen, pancreas, kidneys, and the uro¬
genital organs. On opening the cavity shortly after death, it will
be observed that the intestines are alternately contracting and
relaxing, but always working down the gut, so as to force onward
the contents. The movement, like that of the heart, is automatic.
It will be noted that the cavity is lined by a glistening serous
membrane which is also reflected over the organs. This membrane
is known as the peritoneum. Its function is to secrete a small -
quantity of fluid to prevent friction and so permit the continual
motion of the bowels to go on without injury.
A striking point is the slight amount or entire absence of fat in
these creatures.
The alimentary tract.—This consists of the mouth, through
which food and water gain entrance to the system, the former being
ground into a pulp by the teeth and softened by the saliva; the
gullet, which conveys the same by the act of swallowing to the
stomach, which is the receptacle for it and in which the major part
of digestion is carried on. By this act the food comes into contact
with juices secreted by various organs, and these juices have the
power of altering the food and abstracting from it certain constitu¬
ents which are required to replenish the wear and tear of the
system. When this act has been sufficiently effected, the altered
food passes into the intestine, a tube many feet in length, in which
digestion is completed, and the altered food passed onwards, acquir¬
ing more and more the character of fæces or dung, till it finally
reaches the rectum, in which the fæces lodge till a certain
quantity is collected and is then discharged through the anus.
The mouth.—The cavity of the mouth is remarkably small, " a
fact which is demonstrated, by the precision with which the food is
passed into it by the proboscis, and the small part which the lips
84
A TREATISE ON ELEPHANTS.
consequently play in the act of prehension."—(Miall and Green-
wood)
The roof of the mouth is quite smooth; the sides are formed
by the cheeks, which are sufficiently loose to permit of limited motion
of the jaws, the powerful muscles of which act chiefly in their grinding
motion. In health the interior of the mouth is pinkish in colour
and moist, the breath not unpleasant, appetite good (the elephant
in its natural state, as has been already remarked, eating from 18
to 20 hours during the 24). The upper lip is blended with the
nostrils to form the trunk; the lower lip is small and pointed.
The cavity of the mouth is occupied chiefly by a muscular organ, the
tongue, which is very small. The tip lies in the groove formed by
the lower lip and the organ is possessed of more freedom posteriorly
than anteriorly. It is the organ of taste. The pharynx is a cavity
situated behind the tongue, and through it the food is conveyed to
the gullet or œsophagus. A description of the teeth has alreadv
been given (see page 65).
Œsophagus or gullet.—The œsophagus or gullet is a muscular
tube extending from the pharynx to the stomach ; the calibre of the
tube is small. On the authority of Dr. Harrison, Tennent gives an
illustration of a muscle passing from the posterior part of the wind-
pipe to the gullet, which he thought u might raise the cardiac orifice
of the stomach and so aid this organ to regurgitate a portion of its
contents into the œsophagus " (see Fig. 32).
Stomach.—The stomach (see Fig. 33) is a simple sac, unlike
that of most herbivora, smooth externally and measures from 2½ to
3 ft. long; that of the last elephant examined (a large tusker)
FIG. 32.—(Esophagus or gullet, after Harrison, from J. E. Tennent.
THE DIGESTIVE SYSTEM.
85
measured 3 ft. 4 ins. It has two extremities, the cardiac and
pyloric, and two openings, one communicating with the gullet known
as the cardiac, and the other with the intestines, the pyloric. The
stomach is situated towards the left side and the spleen is attached
to it. The cardiac end is long and tapering; the interior is lined
by mucous membrane. " A number of transverse, nearly circular
folds project inward from the cardiac wall; they almost disappear
when the stomach is greatly distended, and are at all times too
shallow to serve as water-cells, though they have been figured and
described as such."—(Miall and Greenwood.)
I have examined
several stomachs and agree with the above remark ; also see remarks
on trunk, page 77. The gullet enters the stomach almost at the
centre.
THE Cells SHOWN ARE MUCH EXAGGERATED,—see DESCRIPTION
OF STOMACH.
Intestines.—The
small intestine begins at the pyloric orifice of
the stomach and ends on entering the caecum, a dilated pouch some
distance down. For convenience the intestine has been divided
into three parts, namely the duodenum, jejunum and ileum. The
intestine may be recognized by its smaller calibre and smooth regular
contour when distended. The secretions poured into the small gut
are bile from the liver, pancreatic juice from the pancreas, and
secretions from glands in its own walls.
The respective total lengths of the small intestine of four
elephants were 66, 70, 73 and 74 ft.
The large intestine is capacious and may be distinguished by its
puckered appearance, due to the presence of longitudinal bands,
which are shorter than the intestine. It is also divided into three
FIG. 33.—Elephant's stomach, after Camper, from J. E. Tennent.