These follicles, looked at individually, may from their minuteness appear insignificant; but directly the immense number of them that exists is taken into account, a proper idea of their significance is obtained. By counting the number of orifices existing in a given space, and reckoning for the whole extent of surface presented by the mucous lining of the stomach, it has been computed by Sappey that there are upwards of five millions of follicles in an average-sized human stomach.

The anatomical arrangement that has been described is the one which recent observation has disclosed as belonging to the human stomach. It does not agree, however, with the description that used to be given, which was drawn from the condition existing in the dog, where the internal surface is marked all over with irregularly hexagonal-shaped pits or depressions known by the name of the gastric alveoli. These gastric alveoli met with in the dog are lined, like the surface of the stomach, with columnar epithelium, and are usually found filled with mucus. It is into the bottom of them that the gastric follicles open, there being clusters of about four or five belonging to each.

Besides the open glandular tubules that have been referred to, closed sacs, corresponding in character, situation, and contents with the solitary glands of the intestine, are frequently to be recognised. It appears that they are not invariably present; at all events, it is not always possible to find them. When present, they are scattered more or less completely throughout the stomach, but are most numerous at its pyloric end. They are more frequently to be found in the stomachs of infants and children than in those of

grown-up persons. Nothing is known with regard to the purpose fulfilled by their presence.

The stomach is an exceedingly vascular organ. One of the three divisions of the coeliac axis is specially set apart for distribution to it, and a further supply of blood is given to it from each of the other two divisions.

The capillaries of the mucous membrane are derived from the ramifications into which the arteries split up in the sub-mucous tunic, or the layer of areolar tissue existing between the mucous and muscular coats. Capillaries proceeding from these ramifications enter the mucous membrane below, and run up between the secreting tubules, around which they form a plexus, towards its free surface. Arrived at the surface, these intertubular capillaries, instead of at once throwing themselves into veins, give origin to the much closer and more capacious set of superficial capillaries which map out and surround the orifices of the gastric tubules. From this latter set, veins arise and pass down between the tubules. This disposition of the intertubular and superficial sets of capillaries of the stomach I believe to contribute towards the security of the organ from self-digestion, in a manner that I shall subsequently point out when referring to the means by which I consider the stomach is enabled to resist undergoing digestion itself during the progress of digestion in its interior.

The veins which collect the blood that has traversed the stomach form a part of the portal system. The blood, therefore, returning from the stomach, is transmitted to and passes through the liver before it reaches the systemic veins.

A nervous supply is given to the stomach from both the cerebro-spinal and sympathetic systems. Branches

are distributed to it from the pneumogastrics; and filaments derived from the large ganglia situated in front of the vertebral column, forming the sympathetic centre connected with the chylo-poietic organs, reach it by coursing in an intricate plexiform manner along its arteries.

Experiment shows that the muscular coat is unquestionably susceptible of being influenced by impressions travelling along the pneumogastrics. Section of these nerves provokes vomiting, if food is contained in the stomach at the time of the operation; and their gal vanic irritation in the recently killed animal visibly throws the stomach into an excited state of movement.

It has formed a debated point, whether or not section of the pneumogastrics stops the secretion of gastric juice. It seems that at first the process of secretion is interfered with; but it is evident, beyond all dispute, that gastric juice must be afterwards secreted; for it has been found that digestion can be subsequently carried on, although, it is true, with less energy than under natural circumstances.

Little or nothing of a positive nature has been ascertained about the influence exerted by the sympathetic upon digestion and the stomach; but it may be premised that it is in an important manner connected with the process of secretion.

The most erroneous ideas formerly prevailed about the nature of gastric digestion. Réaumur and Spallanzani were the first to show that the reduction of food in the stomach is due to the influence of a solvent fluid poured out from the walls of the organ. These experimentalits caused animals to swallow perforated metal tubes and balls containing food, and found that the

food, notwithstanding its position, underwent digestion. and was removed. They also introduced pieces of sponge in their perforated tubes and balls; and on withdrawing them, after they had been in the stomach a little while, by means of a string attached, they obtained some of the gastric secretion. This they experimented with, and found that they could get digestion performed outside the stomach. But Spallanzani further experimented upon himself. Swallowing some small perforated wooden tubes containing food, he afterwards excited vomiting, and was enabled to observe the effects that had been produced by his own gastric juice.

By these experiments, the prevalent notion of the day—namely, that digestion depended upon a compressing action exerted by the muscular fibres of the stomach-was dispersed. The reduction of food in the stomach had been hitherto looked upon as effected by a process analogous to that by which reduction is accomplished in the gizzard of the bird. The gizzard, however, is not the homologue of a stomach it is simply a triturating and not a digesting organ, and occupies in reality the place of the masticating apparatus of the mammal.

For much of the information we possess regarding the precise phenomena of digestion, we are indebted originally to the advantage that was taken of a rare opportunity that presented itself of watching what occurred in the interior of the living stomach of an individual who had met with a gunshot accident that left a permanent opening leading direct from the surface into the cavity of the organ. Since the occurrence of this case, an artificial opening has been made into the stomachs of the lower animals, and experi

ments thereby performed which have confirmed and extended the knowledge previously obtained.

Alexis St. Martin is the name of the person referred to, whose case furnished the opportunity, which was taken advantage of by Dr. Beaumont, a surgeon in the United States Army, for conducting the researches from which issued the first complete account of the process of gastric digestion.

In June, 1822, Alexis St. Martin, a Canadian by birth, and at the time about eighteen years of age, received a charge of duck-shot in his left side, from the accidental discharge of a gun, the muzzle of which was not more than a yard off. The charge entered his side from behind, and passed in an oblique direction forwards and inwards,-"literally," it is stated, "blowing off integuments and muscles of the size of a man's hand, fracturing and carrying away the anterior half of the sixth rib, fracturing the fifth, lacerating the lower portion of the left lobe of the lungs and the diaphragm, and perforating the stomach."

From this extensive injury the young Canadian, miraculously enough, soon became restored to a perfect state of health. The wound healed, with the exception of the opening made into the stomach, which resisted every measure to close it. A compress and bandage had at first to be applied to retain the food in the stomach; but afterwards a fold of mucous membrane came down into the opening, which, in a valvular manner, closed it from above, so as to dispense with the necessity of any external appliance to prevent the escape of what had been taken. "This valvular formation," says Beaumont, "adapted itself to the accidental orifice so as completely to prevent the efflux of the