ments of the stomach could be both seen and felt; and it was noticed, that instead of the vomiting being dependent upon the pressure of the diaphragm on the stomach, it occurred at the time of expiration; and was arrested during inspiration, because the depressed diaphragm then closes the inferior extremity of the oesophagus with such strength, that the contents cannot be forced into the oesophagus when we press upon the organ with both hands. The views of Portal were confirmed by the experiments of Dr. Haighton.' He opened several animals during the efforts of vomiting; and states that he distinctly saw the contractions of the stomach.

In more recent times, the physiological world has been again agitated with this question. In 1813, M. Magendie' presented to the French Institute the results of a series of experiments on dogs and cats,animals, that vomit with facility. Six grains of tartrate of antimony and potassa were given to a dog, and, when he became affected with nausea, the linea alba was divided, and the finger introduced into the abdomen to detect the state of the stomach. No contraction was felt; the organ appeared simply pressed upon by the liver and intestines crowded upon it by the contracted diaphragm and abdominal muscles. Nor was any contraction of the stomach perceptible to the eye; on the contrary, it appeared full of air, and three times its usual size. The air manifestly came from the oesophagus, as a ligature, applied round the cardia, completely shut it off. From this experiment, M. Magendie inferred, that the stomach is passive in vomiting. A solution of four grains of tartrate of antimony and potassa in two ounces of water was injected into the veins of a dog; and, as soon as nausea took place, an incision was made into the abdomen, and the stomach drawn out of the cavity. Although the retching continued, the viscus remained immovable; and the efforts were vain. If, on the other hand, the anterior and posterior surfaces of the stomach were pressed upon by the hands, vomiting occurred, even when no tartrate was administered,-the pressure provoking the contraction of the diaphragm and abdominal muscles, and thus exhibiting the close sympathetic connexion, existing between those acts. A slight pull at the oesophagus was attended with a similar result. In another dog, the abdomen was opened; the vessels of the stomach tied; and the viscus extirpated. A solution of two grains of tartrate of antimony and potassa in an ounce and a half of water was then injected into the veins of the animal, when nausea and fruitless efforts to vomit supervened. The injection was repeated six times: and always with the same results.--In another dog, the stomach was extirpated, and a hog's bladder fitted to the oesophagus in its stead, containing a pint of water, which distended but did not fill it. The whole was then put into the abdomen; the parietes of which were closed by suture. A solution of tartrate of antimony and potassa was now injected into the jugular vein: nausea-and, afterwards, vomiting--supervened, and the fluid was forced from the bladder.-In another dog, the phrenic nerves were divided; by which three-fourths of the diaphragm were paralysed; the dorsal being the only nerves of

1 Memoirs of the Lond. Med. Society, vol. ii.

2 Mémoire sur le Vomissement, Paris, 1813; and Précis Élémentaire, edit. cit., ii. 152.

motion remaining untouched. When tartrate of antimony and potassa was injected into the veins of this animal, but slight vomiting occurred; and this ceased, when the abdomen was opened, and the stomach forcibly pressed upon. In another dog, the abdominal muscles were detached from the sides and linea alba;--the.only part of the parietes remaining being the peritoneum. A solution of tartrate of antimony and potassa was now injected into the veins: nausea and vomiting supervened; and, through the peritoneum, the stomach was observed immovable; whilst the diaphragm pressed down the viscera so strongly against the peritoneum, that it gave way, and the linea alba alone resisted.-In a final experiment, he combined the last two. He cut the phrenic nerves to paralyse the diaphragm; and removed the abdominal muscles. Vomiting was no longer excited.

From these different results, M. Magendie decided, that vomiting takes place independently of the stomach; and, on the other hand, that it cannot occur without the agency of the diaphragm and abdominal muscles; and he concluded, that the stomach is almost passive in the act; that the diaphragm and abdominal muscles, especially the first, are the principal agents;--that air is constantly swallowed at the time of vomiting, to give the stomach the bulk which is necessary, in order that it may be compressed by those muscles; and lastly, that the diaphragm and abdominal muscles are largely concerned in vomiting, as is indicated by their evident and powerful contractions, and by the fatigue felt in them afterwards. In corroboration of his view, M. Magendie refers to cases of scirrhous pylorus, in which there is constant vomiting, although a part of the tissue of the stomach has become of cartilaginous hardness, and, consequently, incapable of contraction.

Clear as the results obtained by this practiced experimenter seem to be, they have been controverted; and attempted to be overthrown by similar experiments. Soon after the appearance of his memoir, M. Maingault' laid before the Society of the Faculté de Médecine of Paris, a series of experiments, from which he deduced very different results. In all, vomiting was produced without the aid of the diaphragm and abdominal muscles. The vomiting was excited by pinching a portion of intestine, which acts more speedily than the injection of substances into the veins. The abdomen of a dog was opened, and a ligature passed round a portion of intestine, which was returned into the abdomen, and the wound closed by suture: vomiting took place. All the abdominal muscles were next extirpated,--the skin, alone, forming the parietes of the cavity. This was brought together, and the vomiting continued. On another dog, three-quarters of the diaphragm were paralysed by the section of the phrenic nerves. The abdomen was now opened, and a ligature placed round a portion of intestine. Vomiting occurred. Lastly;-these two experiments were united into one. The abdominal muscles were cut crucially, and removed; the phrenic nerves divided; and the diaphragm was cut away from its fleshy portion towards its tendinous centre; leaving only a portion as broad as the finger under the sternum. The integuments were not brought together; yet vomiting continued.

Mémoire sur le Vomissement, Paris, 1813.

As these results were obtained on numerous repetitions of the experiment, M. Maingault conceived himself justified in deducing inferences opposite to those of M. Magendie, namely,-that the contraction of the diaphragm and abdominal muscles is only accessory to the act of vomiting; that the action of the stomach is its principal cause;— that the latter is not a convulsive contraction, which strikes the eye, but a slow, antiperistaltic action; and that the only convulsive movement is the contraction of the oesophagus, which drags the stomach upwards. He adduces, moreover, various considerations in favour of his deductions. If the stomach, he asks, be passive, why does it possess nerves, vessels, and muscular fibres? Why is vomiting more energetic, when the stomach is pinched nearer to its pyloric orifice? Why are the ruga of the mucous membrane of the stomach, during vomiting, directed in a divergent manner from the cardiac and pyloric orifices towards the middle portion of the organ? If the diaphragm does all, why do we not vomit whenever that muscle contracts forcibly? Why does not the diaphragm produce the discharge of urine in paralysis of the bladder? Why is vomiting not a voluntary phenomenon? And, lastly, how is it that it occurs in birds, which have no diaphragm?

The minds of physiologists were of course distracted by these conflicting results. M. Richerand' embraced the views of M. Magendie; and affirmed, that he had never observed contraction of the stomach; and that it seemed to him the least contractile of any part of the intestinal canal. With regard to the experiments of M. Maingault, he considered, that the stomach had not been wholly separated from the surrounding muscles; that the action of the pillars of the diaphragm, and the spasmodic constriction of the hypochondres are sufficient to compress the viscus; that nothing is more difficult to effect than the section of the phrenic nerves below their last root; and, moreover, such section does not entirely paralyse the diaphragm, as the muscle still receives twigs from the intercostal nerves and great sympathetic; that the cardia, being more expanded than the pylorus, the passage of substances through it is rendered easy; and that it is incorrect to say, that the cardiac orifice, during inspiration, is closed between the pillars of the diaphragm. Again, to object that, according to the theory of M. Magendie, vomiting ought to be a voluntary phenomenon, is a feeble argument; for it is admitted, that the muscles, which, at the time, compress the stomach, act convulsively. If the diaphragm, in paralysis of the bladder, cannot effect the excretion of the urine, it is because that reservoir is not favourably situate as regards the muscle; and, lastly, the arguments deduced from birds, that they are capable of vomiting, although they have no diaphragm, is equally insufficient, for it is not absolutely necessary that it should be a diaphragm, but any muscle that can compress the stomach.

When the Memoir of M. Maingault was presented to the society of the Faculté de Médecine, M. Legallois and Professor Béclard were named reporters. The experiments were repeated before them by M. Maingault; but, instead of appearing contradictory to those of Ma

1 Nouveaux Élémens de Physiologie, 7ème édit., Paris, 1817.

gendie, these gentlemen declared, that they were not sufficiently multiplied, nor sufficiently various, to lead to any positive conclusion. MM. Legallois and Béclard subsequently repeated and varied them; and instituted others, from which they deduced corollaries, entirely conformable to those of M. Magendie; and lastly, M. Bégin' boldly affirms, "without fear of being contradicted by facts, that there is no direct or authentic experiment, that demonstrates the activity of the stomach during vomiting:"-and he adds, "I have repeated the greater part of the experiments of Magendie; he has performed all in presence of a great number of spectators, of whom I was one; and I can say, with the commissioners of the Académie des Sciences, that I have seen, examined, touched, and my conviction is full and entire." Still, many eminent physiologists have adhered to the idea, that the stomach is the main agent in vomiting; and among these was M. Broussais. He manifestly, however, confounded the phenomena of regurgitation with those of vomiting; which, we have endeavoured to show, are distinct.

A case of wound of the left hypochondrium with escape of the stomach was described to the Académie Royale de Médecine, by M. Lépine, and reported upon by MM. Lagneau, Gimelle, and Bérard, which confirms the views adopted by M. Magendie. During the whole of the period, that the stomach remained out of the abdominal cavity, there was no apparent contraction of the muscular fibres of the organ, and none of its contents were expelled, although the patient made violent efforts to vomit. As soon, however, as the stomach had been returned into the abdomen, the efforts were followed by the expulsion of its contents. M. Lépine confirms the observations of Magendie in another point. After each act of vomiting, the patient appeared to swallow air. "I observed him," says M. Lépine, "execute repeated acts of deglutition, each of which was accompanied by a noise, that seemed to be owing to the passing back of air."

On the whole, we are, perhaps, justified in concluding, that the ancient doctrine regarding vomiting is full of error, and ought to be discarded; that the inverted action of the stomach, although not energetic, is necessary,-that the pressure, exerted on the parietes of the stomach by the diaphragm and abdominal muscles, is a powerful cause, -and that the more or less complete paralysis of the diaphragm, or destruction of the abdominal muscles, renders vomiting more feeble and more slow in manifesting itself. The deep inspiration preceding the act of vomiting, is terminated by the closure of the glottis: after this the diaphragm cannot move without expanding or compressing the

Bulletin de la Faculté et de la Société de Méd., 1813, No. x., and Œuvres de Legallois, Paris, 1824.

2 Traité de Thérapeutique, Paris, 1825.

Traité de Physiologie, etc., translated by Drs. Bell and La Roche, p. 345, Philad., 1832.

Bulletin de l'Académie Royale de Médecine, 1844. See cases cited in Philad. Med. Examiner, April 20, 1844, p. 92; also a case of Wound of Abdomen, in Amer. Journ. of the Med. Sciences, Oct. 1846, p. 379.

The case described by Lépine has, as properly remarked by Dr. Brinton, (Cyclop. of Anat. and Physiology, art. Stomach and Intestines, Pt. 46, p. 317, Lond., 1855,) "been strangely misquoted by many English authors." See Kirkes and Paget, Manual of Physiology, 2d Amer. edit., p. 180, Philad., 1853; and Carpenter, Principles of Human Physiology, Amer. edit., p. 96, Philad., 1855.

air in the lungs. It, consequently, presents a resisting surface, against which the stomach may be pressed by the contracting abdominal muscles. The order of the phenomena seems to be as follows. The brain is affected directly or indirectly by the cause exciting vomiting;through the brain and medulla, the glottis is closed, and the diaphragm and abdominal muscles are thrown into appropriate contraction, and press upon the stomach; this organ probably contracts from the pylorus towards the cardia; and, by the combination of efforts, the contents are propelled into the oesophagus, and out of the mouth. These efforts are repeated several times in succession, and then cease, —to reappear at times. Whilst the rejected matters pass through the pharynx and mouth, the glottis closes; the velum palati rises and becomes horizontal as in deglutition; but owing to the convulsive action of the parts, these apertures are less accurately closed, and more or less of the vomited matter passes into the larynx or nasal fossæ. On account of the suspension of respiration impeding the return of blood from the upper parts of the body, and partly owing to the force with which the blood is sent through the arteries, the face is flushed, or livid, the perspiration flows in abundance, and the secretion of tears is largely augmented.

CHAPTER II.

ABSORPTION.

IN the consideration of the preceding functions, we have seen the alimentary matter subjected to various actions and alterations; and at length, in the small intestine, possessed of the necessary physical constitution for the chyle to be separated from it. Into the mode in which this separation,--which we shall find is not simply a secerning action, but one of vital elaboration,-is effected, we have now to inquire. It constitutes the function of absorption, and its object is to convey the nutritive fluid, formed from the food, into the current of the circulation. Absorption is not, however, confined to the formation of this fluid. Liquids can pass into the blood directly through the coats of the containing vessel, without having been subjected to any elaboration; and the different constituents of the organs are constantly subjected to the absorbing action of cells, by which their decomposition is effected, and their elements conveyed into the blood; whilst antago nizing cells elaborate from the blood, and deposit fresh particles in the place of those that have been removed. These various substances, -bone, muscle, hair, nail, as the case may be, are never found, in their compound state, in the blood; and the inference, consequently, is that at the very radicles of the absorbents and exhalants, the substance on which absorption or exhalation has to be effected, is reduced to its constituents, and this by an action, to which we know nothing similar in physics or chemistry; hence, it has been inferred, that the operation is one of the acts of vitality.

All the various absorptions may be classed under two heads:-the external and the internal; the former including those that take place