EFFECTS OF DISTENTION OF THE INTESTINE 237 



are dependent upon the contraction of the intestinal tube. He 

 beheved that during the movements of normal peristalsis there 

 is a continual changing in the form of the villi. He also noted 

 that the intrinsic muscle fibers of the villi act as the antago- 

 nists of those of the muscularis of the intestine wall. 



Later, in his "Microscopical morphology of the human body" 

 ('83), Heitzmann expressed the same idea: 



• 



The villi are reduplications of the mucosa, of a conical or cylindri- 

 cal shape, very long and narrow in portions where the muscle of the 

 intestine is contracted; broad and short, on the contrary, where the 

 muscle of the intestine is extended. In the highest degrees of disten- 

 tion (by gaseous material) the inner surface of the mucosa is smooth, 

 and no villi are perceptible. 



Heitzmann made no mention of effects of distention upon 

 the shapes of glands. 



Verson ('71) in his description of the villi of the small intes- 

 tine, says: 



Sie sind bald cylindrisch, bald kegelformig, bald keulenformig oder 

 artig ausgebreitet, was zum Theil vom Contractionzustand der Mus- 

 kelhaute unci ihrer eigenen Muskulatur abhangt und weshalb auch ihre 

 Lange sehr wechselnd ist. 



In a study of intestinal contraction Mall ('96) found that 

 the injection of oil into tied-off pieces of intestine of the dog 

 brought about a shortening of both villi and glands and that 

 up to a certain limit, the shortening varied directly with the 

 amount of distention. 



Harvey ('08) studied the large intestine of the dog and man 

 and found that the length and breadth of the intestinal glands 

 varied with distention and contraction of the intestinal tube. 

 From a limited number of observations he concluded that the 

 glands of the transverse colon are subject normally to greater 

 changes in length and breadth, and those of the ascending colon 

 to smaller changes, than the glands of other parts of the large 

 intestine. He made no mention of the effects of distention upon 

 the villi and glands of the small intestine. 



