iv DIGESTION IN THE INTESTINE . 235 



peristaltic movements (which are only seen in the filled and 

 distended jejunum), the ring of constriction travels like a rapidly 

 revolving wheel over long portions of the gut, driving the intestinal 

 contents forward tumultuously in the direction of the caecum. This 

 rapid, vigorous, and extensive wave of peristalsis was termed by 

 van Braam-Houckgeest the roll movement (fiollbewegung). 



Antiperistaltic movements, i.e. movements in the direction of 

 the pylorus, are never observed under normal conditions. They 

 were formerly assumed to exist, as asserted by Engelmann in 

 1871, owing to the effect of mechanically exciting the intestine, 

 which produces a descending peristaltic and an ascending anti- 

 peristaltic wave. In living animals kept under the salt bath, 

 and also in the isolated loop with the Thiry-Vella method, anti- 

 peristaltic movements never occur. Fibini (1883) studied the 

 behaviour of a wax bolus introduced into a Vella's loop, and saw 

 that under normal conditions it travelled 1 cm. in 55 min. Ketro- 

 grade movements, due to the supposed antiperistalsis, never 

 occurred. On the other hand, increase of speed was noted when a 

 faradic stimulus was applied to the proximal end of the loop 

 (velocity = 1 cm. in 10 min.). Psychical influences (fear) also 

 increased the speed of the bolus. 



Some clinicians, however, admit the existence of antiperistaltic 

 movements (at least under pathological conditions) to account for 

 faecal vomiting, consequent on stricture of the intestine ; but this 

 may also be caused by regurgitation due to the energetic action of 

 abdominal compression, independent of the intestinal contractions, 

 as already affirmed by van Swieten. 



The experimental results of excising a more or less extensive 

 segment of gut, and then suturing it in the reverse direction, so 

 that the lower end is joined to the upper part of the intestine, and 

 the upper end to the lower part leading to the ileo-caecal valve, 

 harmonise with the theory that normal peristalsis is descending. 

 These remarkable experiments were first made by Mall, and 

 repeated by Kirstein (1889), then by Kauders (1893), and later 

 by Fasola and Sabbatani (1899). Many of the animals in which 

 this inversion of a loop of intestine was attempted died in the 

 first 2 days after the operation from purulent peritonitis, 

 caused by intestinal perforation owing to laceration at the 

 upper suture, where the intestinal contents accumulate and 

 stagnate. Kirstein, however, succeeded under special conditions 

 in keeping 2 dogs alive. Two cats survived with Kauders for 

 10-11 weeks. In the first week there was nothing abnormal 

 in their nutrition or defaecation; after that they began 

 to refuse food, and died with every symptom of slow starva- 

 tion. Out of 20 dogs operated on, Fasola and Sabbatani lost 

 in the first 2 days all in which the greater part of the small 

 intestine was reversed, as well as those in which the inverted 



