242 PHYSIOLOGY CHAP. 



l.lic sdii-nia (if Fig. 79. With this arrangement it is possible to record 

 simultaneous Irarings of the circular and the longitudinal coat of the 

 intestine. 



The rhythmical (systolic and diastolic) pendular movements 

 are due to synchronous rhythmical contractions and expansions of 



Upper . . Lower 



a b 



Fio. 70. Two enterographs placed at right angles on a segment of intestine, a, b, levers of 

 enterograph recording contractions of longitudinal coat, c, <?, levers of enterograph recording 

 contractions of circular coat. (Bayliss and Starling.) 



both longitudinal and circular fibres (Fig. 80). They are more 

 or less visible in the whole coil of intestine, when exposed and 

 immured in the bath. They recur some 10-12 times per minute, 

 and course over the gut from above downwards at a velocity of 

 2-3 cm. per sec. (Fig. 81). Bayliss and Starling hold that these 

 movements are entirely myogenic in origin, i.e. due to automatic 



B 



Fin. SO. Rhythmic contractions of intestine. (Bayliss and Starling.) A, systolic and diastolic 

 movements of intestine. Balloon method. Time marking = seconds. B, same movements as 

 A, recorded by two enterograplis, showing synchronous activity of longitudinal (7.) and 

 circular ((.') muscle-fibres at same spot. The descending direction of the arrows indicates 

 direction of contraction. 1 



rhythmical activity inherent in the muscle cells, and that they 

 are propagated by muscular conduction, as assumed by Engelmann, 

 Gaskell, and Fauo for cardiac rhythm. 



In direct contradiction to this thesis we have Yanase's observa- 

 tions on the intestinal movements of embryo rabbits and the 

 human foetus in premature abortion. He found that the period 



1 In all curves recorded by Bayliss and Starling with the balloon method, 

 contraction causes an upward movement of the lever. In the curves obtained by 

 means of the enterograph, contraction is signified by a ilownicurd movement. 

 Curves to be read from left to right. TRANSLATOR. 



