Part 8

M. Flourens repeated this experiment a great many times, with herbs of various kinds, and the result was constantly the same: from which it appears, that herbaceous food, on its first deglutition, enters into the honeycomb, as well as into the paunch; the proportion, however, being considerably greater into the paunch than into the honeycomb. It appears equally certain that, in the first swallowing, this kind of food only enters into the first two cavities, and never passes into the many-plies or the reed.

Having ascertained this fact with respect to herbs, he instituted a similar series of experiments, in which the animals were fed upon various kinds of grain,--rye, barley, wheat, oats, &c. The animals were killed and examined, as in the former experiments, immediately after being fed. He found the greater part of the grain unmasticated (tout entier) in the paunch; but, as in the case of the herbs, he also found a certain portion, in the same unmasticated state, in the honeycomb. Neither the many-plies nor the reed contained a single grain. He repeated these experiments many times, and always with the same result.

He then tried the effect of carrots cut into pieces, from half an inch to an inch in length; and in order that the animals might not chew them, he passed them into the pharynx by means of a tube. In one of these sheep he found all the morsels in the paunch; but, in the other two, some of the morsels were in the honeycomb, and some in the paunch. In all the three cases, there was none either in the many-plies or in the reed.

He then proceeded to ascertain the effect of substances previously comminuted. He caused a certain quantity of carrots to be reduced to a kind of mash, with which he fed two sheep, and opened them immediately afterwards. He found the greatest part of this mash in the paunch and in the honeycomb; but he likewise found a certain portion in the many-plies and in the reed.

His next experiments were made upon plain fluids. It is the opinion of the generality of authors on this subject that fluids pass immediately and entirely, along the gastro-duct, into the third and fourth cavities. But, according to the experiments of M. Flourens, this is not the case. He found, by making artificial openings (anus artificiel) in the stomachs of various sheep, that, as the animals drank, the fluid came directly out at the opening, in whatever cavity it might have been made.

It is clear, then, that fluids pass, in part, into the first and second cavities, and, in part, into the third and fourth; and they pass as directly into the former as into the latter.

The following is the result of some experiments which M. Flourens made respecting the formation of the pellets.

In the first place, after the animal has swallowed a certain quantity of food the first time, successive pellets are formed of this food, which remount singly to the mouth; secondly, there is a particular apparatus, which forms these pellets; and, thirdly, this apparatus consists of the two closed apertures (ouvertures fermees) of the many-plies, and of the oesophagus. Thus, the first two cavities, in contracting, push the aliments which they contain between the edges of the gastro-duct; and the gastro-duct, contracting in its turn, draws together the two openings of the many-plies and oesophagus; and these two openings, closed at this moment of their action, seize a portion of the food, detach it, and form it into a pellet.

The chief utility of rumination, as applicable to all the animals in which it takes place, and the final purpose of this wonderfully-complicated function in the animal economy, are still imperfectly known; what has been already suggested on these points is quite unsatisfactory. Perrault and others supposed that it contributed to the security of those animals, which are at once voracious and timid, by showing the necessity of their remaining long employed in chewing in an open pasture; but the Indian buffalo ruminates, although it does not fly even from the lion; and the wild goat dwells in Alpine countries, which are inaccessible to beasts of prey.

Whatever may be our ignorance of the cause or the object of rumination, it is certain that the nature of the food has a considerable influence in increasing or diminishing the necessity for the performance of that function. Thus, dry food requires to be entirely subjected to a second mastication, before it can pass into the many-plies and reed; whilst a great portion of that which is moist and succulent passes readily into those cavities, on its first descent into the stomach.

It has already been shown by the illustration, (p. 4,) that the paunch is the largest of the four cavities; but this is not the case with the stomach of the young calf, which, while it continues to suck, does not ruminate; in this case the reed, which is the true digestive cavity, is actually larger than the other three taken together.

When the calf begins to feed upon solid food, then it begins to ruminate; and as the quantity of solid food is increased, so does the size of the paunch increase, until it attains its full dimensions. In this latter case, the paunch has become considerably larger than the other three cavities taken together.

A curious modification of an organ to adjust itself to the altered condition of the animal is beautifully shown in the instance now under consideration, the nature of which will be easily understood by a reference to the following diagrams, giving the exact relative proportions of the different cavities of the stomach to each other in the young calf and in the full-grown cow.

The letters refer to the same parts in each figure: a, the paunch; b, the honeycomb bag; c, the many-plies; d, the reed.

In all herbivorous animals, and especially those of the ruminating kind, the alimentary canal is of an enormous length; measuring in a full grown ox, as much as sixty yards. The paunch, in such an animal, will hold from fifteen to eighteen gallons.

Blumenbach observes, that the process of rumination supposes a power of voluntary motion in the oesophagus; and, indeed, the influence of the will throughout the whole process is incontestible. It is not confined to any particular time, since the animal can delay it according to circumstances, even when the paunch is quite full. It has been expressly stated of some men, who have had the power of ruminating, that it was quite voluntary with them. Blumenbach knew four men who ruminated their food, and they assured him they had a real enjoyment in doing it: two of them had the power of doing or abstaining from it at their pleasure.

A case of human rumination occurred some years ago at Bristol, the particulars of which are minutely recorded in the 'Philosophical Transactions.' It seemed, in this instance, to have been hereditary, as the father of the individual was subject to the same habit. The young man usually began to chew his food over again, within a quarter of an hour after eating. His ruminating after a full meal generally lasted about an hour and a half; nor could he sleep until this task was completed. The victuals, upon its return, tasted even more pleasantly than at first; and seemed as if it had been beaten up in a mortar. If he ate a variety of things, that which he ate first, came up again first; and if this return was interrupted for any length of time, it produced sickness and disorder; nor was he ever well till it returned. These singular cases are caused, no doubt, by some abnormal structure of the interior of the stomach. No account has yet been given of the dissection of an individual so constituted.

When cattle are at rest, or not employed in grazing or chewing the cud, they are observed frequently to lick themselves. By this means they raise up the hair of their coats, and often swallow it in considerable quantities. The hair thus swallowed gradually accumulates in the stomach, where it is formed into smooth round balls, which, in time, become invested with a hardish brown crust, composed, apparently, of inspissated mucilage, that, by continual friction from the coats of the stomach, becomes hard and glossy. It is generally in the paunch that these hair-balls are found. They vary in weight from a few ounces to six or seven pounds. Mr. Walton, author of an 'Account of the Peruvian Sheep,' makes mention of one that he had in his possession which weighed eight pounds and a quarter. This hair-ball had been taken from a cow that fed on the Pampas of Buenos Ayres. It was of a flat circular shape, and measured two feet eleven inches and a half in circumference; two feet eight inches round the flat part; nine inches diameter also in the flat part; eleven inches diameter in the cross part; and, on immersing it in water, it displaced upwards of eight quarts, which made its bulk correspond to 462 cubic inches. The digestive functions are sometimes seriously impaired by these concretions; a loss of appetite ensues, and general debility.

In the Museum of Daniel Crosthwaite, there is a very extraordinary ball of hair, taken from a fatted calf only seven weeks old. The ball of hair, when taken out of the animal's stomach, and full of moisture, weighed eleven ounces. The calf was fatted by Daniel Thwaite, of Dale Head Hall, within six miles of Keswick; and slaughtered by John Fisher, butcher, Keswick. The calf was a particularly healthy animal.

Before closing this brief sketch of the digestive apparatus of the ox, it may not be uninteresting to quote some of the quaint speculations of Nathaniel Grew on this subject, from his 'Comparative Anatomy of Stomachs and Guts.'

He says: "The voluntary motion of the stomach is that only which accompanies rumination. That it is truly voluntary, is clear, from the command that ruminating animals have of that action. For this purpose it is, that the muscules of their venters are so thick and strong; and have several duplicatures, as the bases of those muscules, whereupon the stress of their motion lies. By means whereof they are able with ease to rowl and tumble any part of the meat from one cell of the same venter to another; or from one venter to another; or from thence into the gullet, whensoever they are minded to do it; so that the ejectment of the meat, in rumination, is a voluntary eructation.

"The pointed knots, like little papillae, in the stomachs of ruminating beasts, are also of great use, namely, for the tasting of the meat. The inner membrane of the first three venters is fibrous (like the gustatory papillae of the tongue) and not glandulous; the fourth only being glandulous, as in a man. Of the fibres of this membrane, and the nervous, are composed those pointed knots, which are, both in substance and shape, altogether like to those upon the tongue. Whence I doubt not, but that the said three ventricles, as they have a power of voluntary motion, so, likewise, that they are the seat of taste, and as truly the organs of that sense, as is the tongue itself."

The mouth of animals of the Ox Tribe contains, when full, thirty-two teeth. Six molars in each jaw, above, below, and on either side; and eight incisors in the lower jaw. In the upper jaw there are no incisors; but instead thereof a fibrous and elastic pad, or cushion, which covers the convex extremity of the anterior maxillary bone, and which is well worthy of observation.

The final cause of this pad (which stands in the place of upper incisor teeth) and the part it plays in the procuring of food, is thus described by Youatt. "The grass is collected and rolled together by means of the long and moveable tongue; it is firmly held between the lower cutting teeth and the pad, the cartilaginous upper lip assisting in this; and then by a sudden nodding motion of the head, the little roll of herbage is either torn or cut off, or partly both torn and cut.

"The intention of this singular method of gathering the food, it is somewhat difficult satisfactorily to explain. It is peculiar to ruminants, who have one large stomach, in which the food is kept as a kind of reservoir until it is ready for the action of the other stomachs. While it is kept there it is in a state of maceration; it is exposed to the united influence of moisture and warmth, and the consequence of this is, that a species of decomposition sometimes commences, and a vast deal of gas is extricated.

"That this should not take place in the natural process of retention and maceration, nature possibly established this mechanism for the first gathering of the food. It is impossible that half of that which is thus procured can be fairly cut through; part will be torn, and no little portion will be torn up by the roots. If cattle are observed while they are grazing, it will be seen that many a root mingles with the blades of grass; and these roots have sometimes no inconsiderable quantity of earth about them. The beast, however, seems not to regard this; he eats on, dirt and all, until his paunch is filled.

"It was designed that this earth should be gathered and swallowed; it was the meaning of this mechanism. A portion of absorbent earth is found in every soil, sufficient not only to prevent the evil that would result from occasional decomposition, by neutralizing the acid principle as rapidly as it is evolved; but, perhaps, by its presence, preventing that decomposition from taking place. Hence the eagerness with which stall-fed cattle, who have not the opportunity of plucking up the roots of grass, evince for mould. It is seldom that a cow will pass a newly-raised mole hill without nuzzling into it, and devouring a considerable portion of it. This is particularly the case where there is any degree of indigestion."

The general disposition of animals of this class, when unmolested, is inoffensive and retiring; but when excited and irritated, they are fierce and courageous, and extremely dangerous to encounter. It is a remarkable circumstance in their history, that they are generally provoked to attack at the sight of red, or any very bright and glaring colour.