PARTS OF ANIMALS, III. xiv. 



happens in the animals which need and take more 

 food owing either to their size or to the heat of these 

 parts of the body. After this, just as it goes into a 

 narrower part of the intestine after it leaves the upper 

 gut," so also it goes into a narrower channel after 

 the colon or wide part of the lower gut,^ and into 

 the spiral coil ; into these the residue passes when 

 its juices have been completely exhausted. In this 

 way Nature is enabled to keep the material in store, 

 and the residue is prevented from passing out all at 

 the same moment. 



In those animals, however, which have to be more 

 controlled in their feeding, there are no great wide 

 spaces in the lower gut, but their intestine is not 

 straight, as it contains many convolutions. Spacious- 

 ness in the gut causes a desire for bulk of food, and 

 straightness in the intestine makes the desire come 

 on again quickly. Hence, animals of this sort are 

 gluttonous : those with simple receptacles eat at very 

 short intervals of time, those with spacious ones eat 

 very large quantities. 



Since the food in the upper gut, when it has just Jejunum, 

 entered, must of necessity be fresh, and M'hen it 

 has proceeded further downwards must have lost its 

 juices and be practically dung, the organ which lies ' 

 between the two must of necessity be something 

 definite, in which the change is effected, where food 

 is no longer fresh and not yet dung. Therefore all 

 animals of this sort have what is called the jejunum, 

 which forms part of the small intestine, which is next 

 to the stomach. That is to say, it has its place 

 between the upper gut, where the unconcocted 

 food is, and the lower gut, where the now useless 

 residue is. All these animals have the. jejunum, but 



' 299 



