The motor function or peristalsis of the intestine has for its objects the thorough mixture of the contents and their propulsion through the entire canal until their final exit through the anus. Nothnagel3 and Braam-Houkgeest 1 have studied the process of intestinal peristalsis in animals. After laparotomy the latter were kept in a bath of physiological salt-water solution of 38° C, and the motions of the intestines were investigated.

1 Schiff: Pfluger's Arch., Bd. 3.

2 Abelmann: "Ueber die Ausnutzung der Nahrungsstoffe nach Pan-kreasexstirpation. " Inaug. Dissert., Dorpat, 1890.

3 H. Nothnagel: "Beitrage zur Physiologie und Pathologie des Darms," Berlin, 1884.

Three types of intestinal peristalsis were discerned: 1. The ordinary peristaltic motion. The intestinal tract contracts at a certain point and thereafter relaxes. The contraction is carried with moderate rapidity for a certain length contiguously in the direction toward the anus and the contents are pushed forward. 2. Oscillating motions. An intestinal coil is here moved to and fro all along its mesentery without any particular contraction at any point. The contents are not propelled, but simply mixed up during these motions. 3. Rotary motions. A filled intestinal coil experiences a circular constriction which is rapidly carried over the intestine for the length of about 20 cm. This is exactly the same process as described under 1, but executed in a violent manner.

While the first two types of intestinal peristalsis are purely physiological, the third type is partly pathological. It is met with only when the contents are mixed with a great deal of gas. Thus, after indiscretions in diet, we often feel this kind of rapid motion going along with a gurgling sound (tormina intestinorum). This type is observed only in the small intestine, but never in the large bowel.

The small intestine manifests much quicker peristalsis than the large bowel, the motions of which are very slow. Here the haustra during the act of peristalsis contract and then protrude in regular order. The small intestine while empty does not show any motion whatever, but after the entrance of chyme into the duodenum intestinal peristalsis begins. It is not, however, transmitted down to the Bau-hinian valve without interruption, but stops as a rule at a certain distance from its starting-point (about 20 cm.). After an intermission of some duration it begins again. Thus one or more intestinal segments may be in a state of peristalsis while other parts of the intestine in between are at rest. The time for the arrival of the first particles of chyme from the duodenum into the caecum is about two hours. But, of course, the intestinal peristalsis must continue until the stomach has expelled the last portions of the chyme, that is to say, within about two hours after the stomach has become empty the small intestine as a rule will also be found free of contents. The forward motion of the contents in the large bowel is a very slow one indeed.

It takes as a rule from twenty to twenty-four hours for the fecal matter to move from the caecum to the rectum.

1 Braam-Houkgeest: Ptiiiger's Arcb., Bd. 7, p. 266.

Antiperistalsis, or reversed motion of the large bowel and the small intestine, beginning at the anus and extending upward, has never been seen by Nothnagel in physiological conditions.

The process of peristalsis is controlled by nervous influences. Auerbach's and Meissner's plexus most probably contain automatic nerve centres for this act. But there are also other centrally located nervous agencies. Thus after great mental excitement diarrhoea very often results, showing that the intestinal peristalsis must have been greatly increased through the influence of the brain. There are also numerous nerves which supervise the motor function of the entire intestinal tract. Pfluger 1 has shown that the splanchnic nerve contains inhibitory fibres for the intestinal peristalsis. According to Ehrmann,1 accelerating and inhibitory fibres supervising intestinal peristalsis are contained in the vagus as well as in the splachnicus, but they have a varied function according to the way they end, whether in the longitudinal or in the circular muscles. The longitudinal muscles are stimulated by the splanchnic and paralyzed by the vagus. The circular muscles, on the other hand, are stimulated by the vagus and paralyzed by the splanchnic.

1 Pfluger: "Ueber das Hemmungs- und Nervensystem fur die peri-staltiscnen Bewegungen der Gedarme," Berlin. 1857.

Normally the chyme acts as a stimulus on the intestinal canal and provokes peristalsis (through the influence of the nerves). Too cold drinks, indigestible food, organic acids (present in too large amount) may often cause an increased peristalsis and thus produce diarrhoea. Toxic substances which are ingested or developed from unwholesome food may have the same effect.

1 Ehrmann: Wiener med. Jahrbucner, 1885.