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Like all mammalia, the Cetaceæ suckle their young at the breast; but, by this latter term, we are not to suppose that they have mammary glands upon the pectoral portion of the body. These long thin flat substances are placed on the inferior and lateral parts of the abdomen, in order, as Hunter well described, that they may not vary the shape, nor interfere with the motions of the animal, and for other reasons to be explained hereafter. The lactiferous ducts are simple cæcal tubes, as in the ornithorhynchus, opening into a long duct or receptacle, which proceeds through the gland to the nipple, and bears a striking analogy to the pancreatic duct in man. Some years ago, Müller published a beautiful plate of this gland, in the Balænoptera Rostrata, and it was accurately described by Hunter, in 1787. The form and position of the nipples, however, require attention. They are two in number—not protuberant from the animal, like the teats of other mammiferæ: but lodged in the bottom of deep sulci or fissures, which, when closed, and the organs are not called upon to exercise their peculiar functions, completely hide them. Thus far we are acquainted with the anatomy of the parts, (at least sufficiently acquainted for the object of this inquiry, or the bearing of a work like this); but a very serious and interesting question here presents itself, viz :-In what manner do the young Cetaceæ suck? Do they respire during that process ? and if so, how are these two functions performed under water?
On this subject, John Hunter made the following observations :
“ The mode in which these animals must suck, would appear to be very inconvenient for respiration, as either the mother or young one will be prevented from breathing at the time, their nostrils being in opposite directions, therefore the nose of one must be under water, and the time of sucking can only be between each respiration. The act of sucking must likewise be different from that of land animals; as in them it is performed by the lungs drawing the air from the mouth backwards into themselves, which the fluid follows, by being forced into the mouth, from the pressure of the external air on its surface; but, in this tribe, the lungs having no connection with the mouth, sucking must be performed by some action of the mouth itself, and by its having the power of expansion.”
Ever since Hunter's day, the mode of sucking has been a stumblingblock to zoologists. A short time ago, Geoffroy St. Hilaire, the celebrated French naturalist, endeavoured to explain it by asserting that he had discovered a certain sac or reservoir into which all the lactiferous tubes
poured their contents, and that a quantity of milk being already contained in this, the young animal had only to apply its mouth to the teat, and immediately certain muscles in the neighbourhood acted both on the gland and on the receptacle, and poured a quantity of milk (often several gallons in the larger species) into the young animal's mouth. This theory seemed plausible, and was generally adopted at the time.
At the meeting of the British Association in Dublin, in 1835, Dr. Arthur Jacob read a paper, calling in question the views promulgated by the French physiologist ; and since then, Frederick Cuvier, in his article on the Cetaceæ, in the Cyclopædia of Anatomy and Physiology, has laboured to refute them. In the first place, as to the sac or reservoir, it was long ago described by Hunter. He says, “ The trunk of this tube is large, and appears to serve as a reservoir for the milk.” Again, concerning the muscle said to act upon the reservoir, a mistake seems to have crept in amongst the anatomists of this country, who have confounded with it the subcutaneous muscle that envelopes the animal. This latter is a kind of dartos, or collection of muscular fibres, mixed with a dense fibro-cellular texture, and spread generally beneath the blubber of the animal-in fact, a panniculus carnosus. I can perfectly agree with those who deny that this acts in circumscribed portions, and I believe that it can exercise but little power over the mammary gland; but that the muscle described by St. Hilaire does exist, there can be no doubt. I have dissected it in the Delphinus Dephis and Phocæna Communis, several of which I had an opportunity of examining in the Mediterranean; and I have the authority of several eminent anatomists, who have likewise satisfied themselves upon the point. It is attached to the pelvic bone, and spreads over the gland in an oblique direction, backwards and upwards towards the spine. But that it exercises this peculiar power of compressing, at will, the gland and its receptacle, I cannot take upon me to say, Independent of it, or any other muscular mechanism, the great pressure of the surrounding medium on the gland, would, as soon as the nipple was grasped, force out the fluid contained within; and the very great extent of this gland in Cetaceæ may be to forward so useful and beautiful a purpose.
In order to explain the subject more fully, it would be necessary to enter into a description of the beautiful mechanism of the parts connected with sucking in the human infant-an office that may be termed the birth of instinct, and one of the very first efforts at voluntary motion; but as this sketch is intended more for those already acquainted with such subjects, it would be unnecessary.
In Cetaceæ, the mouth, when opened, presents a purse-like cavity, similar to that of a crocodile ; with this difference, that the mouth in the Cetaceans has no connection with the respiratory function, which is exclusively confined to the blow-hole, on the fore-part of the head. The glottis stands above the level of the roof of the mouth and soft palate ;
it rises up into the cavity connected with the blow-hole, and being slung by the hyoid bone, and a complicated muscular apparatus, from the base of the skull, can be drawn up, during the act of respiration, into the blow-hole; and the soft palate being horizontal, surrounds the larynx like a collar, in order more completely to insulate it from the cavity of the month. The food therefore passes into the esophagus by deep channels on either side of the larynx. While dissecting these parts lately, I found, on the anterior margin of the soft palate, where it is touched by the larynx, what at first appeared an uvula, but, on examination, it turned out to be a considerable glandular body-a collection of mucous follicles, not unlike the tonsil, and serving, by their secretion, to lubricate the top of the larynx, as it passed by it, in each act of respiration. From this mechanism of the mouth and throat we learn, that in those animals sucking cannot be performed on the principle of exhaustion of the mouth by inspiration, as (according to some physiologists) it is in infants. It appears to depend more on the mechanical adaptation of the muscles of the mouth and tongue acting directly on the nipple, and few animals possess this apparatus in greater perfection than the dolphins and porpoises, and several of the larger whalesowing chiefly to the mouth being perfectly unconnected with respiration. Indeed, it may be doubted whether, if the blow-hole was closed, the animal could respire.
Dr. Jacob enumerates three modes by which the animal sucks under water :-First, By exhausting the cavity of mouth closed by the soft palate bebind, by depressing the tongue ; secondly, By exhausting the mouth by the diaphragm; and thirdly, by the squeezing and pulling of the nipple, by the gums of the young animal. The second of these, I confess, I do not understand. How the descent of the diaphragm in an animal, whose mouth is not at all connected with the respiratory apparatus, could assist sucking, it is difficult to conceive. The last appears to me to afford the desired explanation. But although Messrs. Jacob and St. Hilaire have told us how the animal may, and, in all probability, does suck under water, neither they, nor any other observers, have told us how the young Cetacean breathes all this time; and the question of John Hunter still remains to be explained; unless we believe that sucking is merely carried on between the periods of respiration, which will occupy generally from two to five minutes—an opinion, to my mind, very improbable.
During our sojourn in the Mediterranean, I had several opportunities of dissecting small Cetaceæ, and almost daily opportunities of observing the motions of hundreds of these animals; and to this motion, during the act of respiration, I would call the attention of physiologists, as it may offer some explanation of the mode of sucking. When the animal comes up to breathe, it protrudes the blow-hole above the water-line, and then making a graceful curve, by describing a semicircle, or, at least, the segment of a very large circle, it raises the extremity of its body and tail completely out of the water in its descent, so as to carry that portion of its under or
abdominal surface, in which the nipples are placed, fairly out of the water into the air. In this way, shoals of them proceed at a rapid pace, never, however, raising the entire body out of the water, but cutting the waterline with their pectoral region, which is generally half emerged. This exact motion cannot be seen in rough weather, when the surface is much disturbed, and when Cetaceans are on the alert, as those in the Mediterranean generally are ; nor could it be well seen from the high deck of a vessel. But I have observed it so often in perfect calms, when in a boat amongst a shoal of them, and having applied my eye as nearly on a level with the surface as I could, that I am convinced on the subject.
Now, it appears to me, that the young one, when it lays hold on the teat, need not necessarily relinquish it each time either it or the mother comes up to breathe. And I am informed by experienced whalers, that they have constantly seen the young ones attached to the mothers for a considerable time, and remaining so while the latter rose to blow. These men had no object in deception, nor any theory to favour and advance ; and the excellent work of Scoresby, on the Whale Fishery and Arctic Regions, would lead us to suppose such to be the case with the large Cetaceæ there.
We know of other animals, for instance, the marsupial, which suckle while they progress; the monkey tribe skip from tree to tree, with the young ones attached to the teats; those animals denominated flying squirrels, and the cheiroptera-viz. the vampire bat, and even the common one of that species----will fly about with the young ones adherent. Nay, we know of Indians and Hottentots who carry their children slung on their backs, and attached to their enormous breasts. And why should not a whale be capable of a similar privilege ? Closet zoologists, supposing that both mother and young could not breathe at the same time, have gone so far as to state that the old one turned on her back to allow the young one to draw the breast ; others, that they lie on the side for a similar purpose. But this being a position they could not long maintain, would be rather too much of natural affection, even in a whale; as, though it might be very convenient for the young one, inevitable drowning would be the consequence to the old, if that position were long sustained.
It appears to me, then, that the young remain attached to the mother during a certain period, as other mammiferæ, and that each time the animal rises to the surface, it lifts the breasts, and consequently the young one, above the water, so that, in fact, all the young one has to do is to hold on, and it is both suckled and assisted to respire at the same time. Perhaps the sulcus in which the nipple is lodged may exert some power of retaining the lips of the animal in situ, by its margin grasping the extremity of the young one's mouth. Perhaps the reason for the parts being placed so low in the abdomen is, that the mother may lift the young one above the water.
The original communication upon this subject, of which this is but a
brief, and, from the nature of this volume, an imperfect sketch, was made to the Obstetrical Society of this city; a society that continues to increase the long and well-earned reputation that has for more than half a century been accorded to that particular branch of science in Ireland, and that reflects upon its talented and enterprising founder, Dr. Evory Kennedy, a lustre that he so well deserves. Since then, some of our most enlightened physiologists have taken up the topic in their public lectures, and approved of the explanation I have offered upon this hitherto undecided question; and these considerations have induced me to give it, in a popular form, unconnected with anatomical details, a place in this appendix.
There is one other subject naturally arising out of any investigation of the Cetaceæ of the Mediterranean—that is, the story of Jonah ; and on this I would suggest the following explanation of what sceptics have long been in the habit of dwelling upon as one of the fallacies of inspired writ.
That Jonah could be preserved for three days and three nights in the belly of a whale, was in itself a miracle, and as such we are bound to believe it even as the old woman said, who answered a casuist, that were she informed by the same Divine authority that Jonah swallowed the whale, she would believe it. Now, although it be a miracle, yet the Almighty generally works his wonders by natural means. First, it is said that the gullet or csophagus of even the largest Cetacean could not admit a man's body ;-this is answered by the very expression used in Scripture, that “the Lord prepared a great fish." Secondly, the whale, although an aquatic animal, yet breathing air by means of lungs, it would be naturally obliged to come to the surface to respire, nearly as often as a man is compelled to perform that function; and so, were Jonah placed behind the enormous cavity of the posterior nares, beneath the blow-hole, he could, even by natural means, be supplied with air. Thirdly, the whole story has by some been described as an allegory; and these persons have particularly dwelt upon the account of the sea-weeds surrounding his head, to show that it must have been on the shore that Jonah was thrown, alleging, that the whale feeding on small mollusca, it was impossible for sea-weed to entangle round the prophet's head ;-in contradiction of this, it is particularly worthy of remark, that some of the very largest whales that inhabit the Mediterranean, are graminivorous, ruminating animals, and consequently feed on Algæ and other marine plants.