GENERATION OF ANIMALS, II. iv. 



the heart is the first principle of them as well. This 

 !•- clearly brought out in the Researches " and in the 

 Dissections. 



Now since the fetation is already an animal potenti- 

 ally, though an imperfect one, it natist get its nourish- 

 ment from elsewhere ; and that is why it makes use 

 of the uterus, i.e., of the mother, just as a plant makes 

 use of the earth, in order to get its nourishment, until 

 such time as it is sufficiently perfected to be a potenti- 

 ally locomotive animal. That is whv Nature pre- 

 scribes * first of all the two blood-vessels that run 

 from the heart ; and attached to these are some small 

 blood-vessels which run to the uterus, forming what 

 is known as the umbilicus, the umbihcus ^ being of 

 course a blood-vessel — a single blood-vessel in some 

 animals, and consisting of more munerous ones in 

 others. Round these blood-vessels there is a skin- 

 like integument, because the blood-vessels being 

 weak need a protective covering to keep them safe 

 and sound. The blood-vessels join on to the uterus 

 as though they were roots, and through thenx the 

 tation gets its nourishment. And that of course 



- the reason why the young animal stays in the 

 uterus (not as Democritus ^ alleges, in order that its 

 parts may be moulded after the fashion of the parts 

 of its mother). This is manifest in the case of the 

 0\ipara, whose parts become distinct in the egg, i.e., 



:"ter they have been separated from the matrix. 

 Here is a puzzle which may be raised. If (1) the 

 blood is nourishment, (2) the heart is the first thing 

 to be formed, and when formed contains blood, and 

 (3) the nourishment comes from outside, from whence 

 did the first nourishment * enter ? Well, perhaps 



* i.e., the blood which is in the heart to begin with. 



197 



