65 



i^hysiology. — " Velocity of the intestinal movements in dijferent 

 mammals." By Dr. E. Laqueur and W. R. van der Meer. 

 (Communicated by Prof. Hamburger). 



It is a well-known fact tliat the metabolism of the smaller kinds 

 of mammals is more intensive than that of the larger kinds. The 

 smaller species not only take comparatively more food, but the need 

 of food makes itself mo)-e frequently felt. To explain the latter fact 

 it mnst be assumed that in the smaller animals the food passes 

 much more rapidly through stomach and intestinal canal than in 

 the bigger ones. This is also borne out by the fact that the smaller 

 species defecate much more frequently than the larger ones. The 

 velocity with which the food passes through the intestinal canal is 

 certainly dependent on the velocity of the intestinal movements. 



Generally speaking the movements of the larger mammals are 

 slow and heavy as compared with the movements of the smaller 

 kinds. The problem relating the velocity of the intestinal movements 

 is the more important since it seems that it is not absolutely certain 

 if the quality mentioned just Jiow. which holds good for (transversely) 

 striated muscles is also found in lissed (non-striated) muscular cells. 



Immediately on the abdominal ca\ity being opened, it becomes 

 manifest that the movements of stomach and intestinal canal are 

 indeed much more rapid in smaller mammals (e. g. rat and mouse) 

 than for instance in the rabbit. The difference becomes still more 

 conspicuous when an intestinal coil is extirpated and allow^ed to move in 

 a suitable warm salt-solution wdiich has been saturated with 0^ (e.g. 

 the one suggested by Tyrode). 



A further investigation of this difference is the object of these 

 researches. For this purpose we adopted the method applied by 

 Magnus when studying the qualities of the "surviving" intestine. As 

 we know he suspended a piece of an intestinal coil in a solution of 37° 

 through which a current of oxygen was led. The contractions of the 

 longitudinal muscle were transferred to a lever and registered. The intes- 

 tines of smaller animals présent some difficulty since the absolute value 

 of the intestinal muscular force is but small. We have examined the intes- 

 tinal movements of 8 kinds of mammals (mouse rat, guinea-pig, rabbit, 

 cat, dog, pig, cowl and that nearly always on duodenum and ileum ^). 



1) I avail myself of this opportunity to tender my best thanks to Prof. C. F. 

 A. Koch, who enabled me .to examine also pieces of intestines of man, which it 

 had been necessary to remove by operations. Until now however, only pieces of 

 coecum and processus vermiformis could be supplied; both parts sliowed very 

 slow movements. 



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Proceedings Royal Acad. Amsterdam. Vol. XVI. 



