190 Letters 



blood which is about to enter the right side of the organ, 

 and that it there obtains a further concoction. But 

 what, some one might with as good reason ask, should 

 hinder it from passing into the porta, then into the liver, 

 and thence into the cava, in conformity with the arrange- 

 ment which Aselli and others are said to have found ? 

 Why, indeed, should we not as well believe that the 

 chyle enters the mouths of the mesenteric veins, and in 

 this way becomes immediately mingled with the blood, 

 where it might receive digestion and perfection from 

 the heat, and serve for the nutrition of all the parts ? 

 For the heart itself can be accounted of higher import- 

 ance than other parts, can be termed the source of 

 heat and of life, upon no other grounds than as it 

 contains a larger quantity of blood in its cavities, 

 where, as Aristotle says, the blood is not contained 

 in veins as it is in other parts, but in an ample sinus 

 and cistern, a,s it were. And that the thing is so in 

 fact, I find an argument in the distribution of innumer- 

 able arteries and veins to the intestines, more than to 

 any other part of the body, in the same way as the 

 uterus abounds with blood-vessels during the period of 

 pregnancy. For nature never acts inconsiderately. In 

 all the red-blooded animals, consequently, which require 

 [abundant] nourishment, we find a copious distribution 

 of mesenteric vessels ; but lacteal veins we discover in 

 but a few, and even in these not constantly. Where- 

 fore, if we are to judge of the uses of parts as w r e meet 

 with them in general and in the greater number of 

 animals, beyond all doubt those filaments of a white 

 colour, and very like the fibres of a spider's web, are 

 not instituted for the purpose of transporting nourish- 

 ment, neither is the fluid they contain to be designated 

 by the name of chyle ; the mesenteric vessels are rather 

 destined to the duty in question. Because, of that 

 whence an animal is constituted, by that must it neces- 

 sarily grow, and by that consequently be nourished ; for 

 the nutritive and augmentative faculties, or nutrition 



