ON GENERATION. 505 



If it be said that these spirits reside in the primigenial 

 moisture as in their ultimate aliment, and flow from thence 

 through the whole body to nourish its several parts, they 

 propound a simple impossibility, viz. that the ingenerate 

 heat, that primigenial element of the body, nourished itself, 

 yet serves for the nourishment of the body at large. Upon 

 such grounds the thing nourished and the thing that nourishes 

 would be one and the same, and itself would both nourish and 

 be nourished; which could in no way be effected; inasmuch as 

 it is by no means probable that the nourishment should ever 

 be mixed with the thing nourished, for things mixed must have 

 equal powers and mutually act on one another ; and, according 

 to Aristotle's dictum, "where there is nutrition, there there 

 is no mixture." But as nutrition takes place everywhere, the 

 nutriment is one thing, and that which is nourished by it is 

 another, and it is altogether indispensable that the one pass 

 into the other. 



But as it is thought that the spirits, and the ultimate or 

 primigenial aliment, or something else, is contained in animals 

 which acts in a greater degree than the blood above the forces 

 of the elements, we are not sufficiently informed what is un- 

 derstood by the expression, " acting above the forces of the ele- 

 ments " neither are Aristotle's words rightly interpreted where 

 he says, 1 " every virtue or faculty of the soul appears to par- 

 take of another body more divine than those which are called 



elements For there is in every seed a certain something 



which causes it to be fruitful, viz. what is called heat, and that 

 not fire or any faculty of the kind, but a spirit such as is con- 

 tained in semen and frothy bodies ; and the nature inherent 

 in that spirit is responsive in its proportions to the element of 

 the stars. Wherefore fire engenders no animal; neither is any- 

 thing seen to be constituted of the dense, or moist, or dry. But 

 the heat of the sun and of animals, and not only that which is 

 stored up in semen, but even that of any excrementitious 

 matter, although diverse in nature, still contains a vital prin- 

 ciple. For the rest, it is obvious from this that the heat con- 

 tained in animals is not fire, neither does it derive its origin from 

 fire." Now I maintain the same things of the innate heat and 



1 De Gen. Anim. lib. ii, cap. 3. 



