StuJii's on Regulaliou 367 



entirely tVoni the preganglionic region, in which it is present in 

 normal well-fed animals (Fig. i). 



In all observed cases of intestinal degeneration, except under 

 certain conditions connected with form-regulation, the course of 

 the process of degeneration is essentially the same and passes 

 through the stages described above. 



Disc 



'US SI on 



According to the above account the intestinal degeneration 

 begins at the extreme peripheral regions of the intestine and pro- 

 ceeds "centripetally." The ends of the branches in the terminal 

 regions are the first parts to disappear, and the last branches to 

 undergo reduction are those immediately about the pharyngeal 

 region. 



It can scarcely be supposed that the more peripheral branches 

 or the more peripheral regions of each branch are less needed than 

 the more central parts and so disappear first. The peripheral 

 portions of the intestine would seem to be just as essential as other 

 parts for proper nutrition. The head-region is the most active 

 region of the body and yet the anterior end of the intestine dis- 

 appears earlier than any other part of the prepharyngeal intestine. 



But when the course of reduction is considered from a functional 

 standpoint interpretation becomes easy. In the first place the 

 quantity of intestinal contents undergoes gradual decrease from 

 the beginning to the end of the experiment. In well-fed animals 

 the intestine is greatly distended (cf. Fig. 2) with food at first. 

 This nutritive material is gradually used up, but as degeneration 

 of the intestinal branches occurs a part of the products of degener- 

 ation appears in the intestine as a fluid crowded with dark granular 

 masses. In normal animals this too undergoes resorption almost 

 or quite as rapidly as it is formed, and gradually decreases in 

 amount as time goes on. Thus even long after the food taken 

 from without has disappeared the intestine is not empty, but the 

 amount of intestinal contents is always decreasing. The move- 

 ments of this dark substance in the intestine can be readily ob- 

 served and the following statements regarding their relation to the 

 general muscular contractions are the result of direct observation. 



