I have thus briefly summarised the osteology of the elephant, as I think the salient points on which I have touched would interest the general reader; but, in now proceeding to the internal anatomy, I shall restrict myself still more, referring only to certain matters affecting externally visible peculiarities. The trunk of the elephant differs somewhat from other nasal prolongations, such as the snouts of certain insectivora, which are simply development of the nasal cartilages. The nasal cartilages in the Proboscidea serve merely as valves to the entrance of the bony nares, the trunk itself being only a pipe or duct leading to them, composed of powerful muscular and membranous tissue and consisting of two tubes, separated by a septum. The muscles in front (levatores proboscidis), starting from the frontal bone, run along a semicircular line, arching upwards above the nasal bones and between the orbits. They are met at the sides by the lateral longitudinal muscles, which blend, and their fibres run the whole length of the proboscis down to the extremity. The depressing muscles (depressores proboscidis), or posterior longitudinals, arise from the anterior surface and lower border of the premaxillaries, and form "two layers of oblique fasciculi along the posterior surface of the proboscis; the fibres of the superficial set are directed downwards and outwards from the middle line. They do not reach the extremity of the trunk, but disappear by curving over the sides a little above the end of the organ. The fibres of the deeper set take the reverse direction, and are attached to a distinct tendinous raphe along the posterior median line" ('Anat. Ind. Elep.,' Miall and Greenwood). These muscles form the outer sheath of other muscles, which radiate from the nasal canals outwards, and which consist of numerous distinct fasciculi. Then there are a set of transverse muscles in two parts—one narrow, forming the septum or partition between the nasal passages, and the other broader between the narrow part and the posterior longitudinal muscles.
When we consider the bulk of these well-knit muscles we can no longer wonder at the power of which this organ is capable, although, according to Mr. Sanderson, its capabilities are much exaggerated; and he explodes various popular delusions concerning it. He doubts the possibility of the animal picking up a needle, the common old story which I also disbelieve, having often seen the difficulty with which a coin is picked up, or rather scraped up; but he quite scouts the idea of an elephant being able to lift a heavy weight with his trunk, giving an instance recorded of one of these creatures lifting with his trunk the axle of a field-piece as the wheel was about to pass over a fallen gunner, which he declares to be a physical impossibility. Certainly the story has many elements of improbability about it, and his comments on it are caustic and amusing: par exemple, when he asks: "How did the elephant know that a wheel going over the man would not be agreeable to him?" That is the weak point in the story—but, however intelligent the animal might be, Mr. Sanderson says it is physically impossible.
Another thing that strikes every one is the noiseless tread of this huge beast. To describe the mechanism of the foot of the elephant concisely and simply I am going to give a few extracts from the observations of Professor W. Boyd Dawkins and Messrs. Oakley, Miall, and Greenwood: "It stands on the ends of its five toes, each of which is terminated by comparatively small hoofs, and the heel-bone is a little distance from the ground. Beneath comes the wonderful cushion composed, of membranes, fat, nerves, and blood-vessels, besides muscles, which constitutes the sole of the foot" (W. B. D. and H. O.). "Of the foot as a whole—and this remark apples to both fore and hind extremities—the separate mobility of the parts is greater than would be suspected from an external inspection, and much greater than in most Ungulates. The palmar and plantar soles, though thick and tough, are not rigid boxes like hoofs, but may be made to bend even by human fingers. The large development of muscles acting upon the carpus and tarsus, and the separate existence of flexors and extensors of individual digits, is further proof that the elephant's foot is far from being a solid unalterable mass. There are, as has been pointed out, tendinous or ligamentous attachments which restrain the independent action of some of these muscles, but anatomical examinations would lead us to suppose that the living animal could at all events accurately direct any part of the circumference of the foot by itself to the ground. The metacarpal and metatarsal bones form a considerable angle with the surface of the sole, while the digits, when supporting the weight of the body, are nearly horizontal" (M. and G.). This formation would naturally give elasticity to the foot, and, with the soft cushion spoken of by Professor Dawkins, would account for the noiselessness of the elephant's tread. On one occasion a friend and myself marched our elephant up to a sleeping tiger without disturbing the latter's slumbers.
It is a curious fact that twice round an elephant's foot is his height; it may be an inch one way or the other, but still sufficiently near to take as an estimate.
Now we come to a third peculiarity in this interesting animal, and that is the power of withdrawing water or a similar fluid from apparently the stomach by the insertion of its trunk into the mouth, which it sprinkles over its body when heated. The operation and the modus operandi are familiar to all who have made much use of elephants, but the internal economy by which the water is supplied is as yet a mystery to be solved, although various anatomists have given the subject serious attention. It is generally supposed that the receptacle for the liquid is the stomach, from the quantity that is ejected. An elephant distressed by a long march in the heat of the sun withdraws several quarts of water, but that it is water, and not a secretion produced by salivatory glands, is not I think sufficiently evident. In talking over the matter with Mr. Sanderson, he informed me that an elephant that has drunk a short time before taking an arduous march has a more plentiful supply of liquid at his disposal. Therefore we might conclude that it is water which is regurgitated, and in such quantity as to preclude the idea of its being stored anywhere but in the stomach; but the question is, how it is so stored there without assimulating with the food in the process of digestion. Sir Emerson Tennent, in his popular and well-known, but in some respects incorrect, account of the elephant, has adopted the theory that the cardiac end of the stomach is the receptacle for the water; and he figures a section of it showing a number of transverse circular folds; and he accepts the conclusion arrived at by Camper and Sir Everard Home that this portion can be shut off as a water chamber by the action of the fold nearest to the oesophagus; but these folds are too shallow to serve as water-cells, and it has not been demonstrated that the broadest fold near the oesophagus can be contracted to such an extent as to form a complete diaphragm bisecting the stomach. Messrs. Miall and Greenwood say: "The stomach is smooth, externally elongate, and nearly straight. The cardiac end is much prolonged and tapering. A number of transverse, nearly circular, folds project inwards 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."
That the stomach is the reservoir is, I think, open to doubt; but there is no other possible receptacle as yet discovered, though I shall allude to a supposed one presently, which would hold a moderate supply of water, and further research in this direction is desirable. Most of the dissections hitherto made have been of young and immature specimens. Dr. Watson's investigations have thrown some light on the way in which the water is withdrawn, which differs from Dr. Harrison's conclusions, which are quoted by Sir Emerson Tennent. Dr. Watson says regarding this power of withdrawal: "It is evident that were the throat of this animal similar to that of other mammals, this could not be accomplished, as the insertion of a body, such as the trunk, so far into the pharynx as to enable the constrictor muscles of that organ to grasp it, would at once give rise to a paroxysm of coughing; or, were the trunk merely inserted into the mouth, it would be requisite that this cavity be kept constantly filled with water, at the same time that the lips closely encircled the inserted trunk. The formation of the mouth of the elephant, however, is such as to prevent the trunk ever being grasped by the lips so as effectually to stop the entrance of air into the cavity, and thus at once, if I may so express it, the pump action of the trunk is completely paralysed. We find, therefore, that it is to some modification of the throat that we must look for an explanation of the function in question." He then goes on to explain minutely the anatomical details of the apparatus of the throat, which I will endeavour to sketch as simply, though clearly, as I can. The superior aperture of the pharynx is extremely narrow, so much so as to admit, with difficulty, the passage of a closed fist; but immediately behind this the pharynx dilates into a large pouch capable of containing a certain quantity of fluid—according to Dr. Watson a considerable quantity; but this is open to question. Professor Miall states that in the young specimen examined by him and Mr. Greenwood, a pint was the capacity of the pouch. However, according to Dr. Watson, it is capable of distention to a certain extent. The pouch is prolonged forward beneath the root of the tongue, which forms the anterior boundary, whilst the posterior wall is completed by depression of the soft palate; when the latter is elevated the pouch communicates freely with the oesophagus. I omit Dr. Watson's minute description of the anatomy of this part in detail, which the reader who cares to study the matter more deeply can find in his 'Contributions to the Anatomy of the Indian Elephant,' 'Journal of Anatomy and Physiology,' 1871-74, but proceed to quote some of his deductions from the observations made: "An elephant can," he says, "as the quotations sufficiently prove, withdraw water from his stomach in two ways—first, it may be regurgitated directly into the nasal passages by the action of the diaphragm and abdominal muscles, the soft palate being at the same time depressed, so as to prevent the passage of water into the mouth. Having in this manner filled the large nasal passages communicating with the trunk, the water contained in them is then forced through the trunk by means of a powerful expiration; or, in the second place, the water may be withdrawn from the cavity of the mouth by means of the trunk inserted into it."
The second deduction is, I think, the more probable one. Before an elephant spirts water over his body, he invariably puts his trunk into his mouth for the liquid, whatever it may be. Messrs. Miall and Greenwood are also against the former supposition, viz. that the fluid is regurgitated into the nasal passages. They say: "We are disposed to question the normal passage of water along this highly-sensitive tract. Examination of the parts discovers no valve or other provision for preventing water, flowing from behind forward, from gaining free entrance into the olfactory recesses." Mr. Sanderson, in discussing the habits of elephants with me, informed me that, from his observations, he was sure that an elephant, in drawing up water, did not fill more than fifteen to eighteen inches of his trunk at a time, which confirms the opinion of the two last-mentioned authors. Now we go on with Dr. Watson's second deduction:—
"It is manifestly impossible that the water can be contained within the cavity of the mouth itself, as I have already shown that the lips in the elephant are so formed as effectually to prevent this. The water regurgitated is, however, by means of the elevation of the soft palate, forced into the pharyngeal pouch. The superior aperture of this pouch being much narrower than the diameter of the pouch itself, and being completely surrounded by the muscular fibres of the stylo-glossus on each side, and the root of the tongue in front, which is prolonged backwards so as to form a free sharp margin, we have thus, as it were, a narrow aperture surrounded by a sphincter muscle, into which the trunk being inserted, and grasped above its dilated extremity by the sphincter arrangement just referred to, air is thus effectually excluded; and, the nasal passages being then exhausted by the act of inspiration, water is lodged within these passages, to be used as the animal thinks fit, either by throwing it over his body, or again returning it into his mouth."
This is doubtless a correct conclusion. The question still remaining open is, What is the fluid—water or a secretion? If water, where is it stowed in sufficient quantity? The testimony of several eminent anatomists appears to be against stomach complications such as before suggested. Dr. Anderson has told me that he had the opportunity of examining the stomachs of two very large elephants, which were perfectly simple, of enormous size; and he was astonished at the extent of mucous surface. If water were drawn from such a stomach, it would be more or less tainted with half-digested food, besides which, when drunk, it would be rapidly absorbed by the mucous surfaces. I think therefore that we may assume that these yield back a very fluid secretion, which is regurgitated, as before suggested, into the pharyngeal pouch, to be withdrawn as required. Sir Emerson Tennent figures, on the authority of Dr. Harrison, a portion of the trachea and oesophagus, connected by a muscle which he supposes "might raise the cardiac orifice of the stomach, and so aid this organ to regurgitate a portion of its contents into the oesophagus," but neither Dr. Watson nor Messrs. Miall and Greenwood have found any trace of this muscle.
Before proceeding to a detailed account of the Indian elephant, I will cursorily sketch the difference between it and its African brother.