580 ON CONCEPTION. 



totle l says " that philosophers are in some sort lovers of fables, 

 seeing that fable is made up of marvels." And indeed men were 

 first led to cultivate philosophy from wondering at what they 

 saw. For my own part, then, when I see nothing left in the 

 uterus after intercourse to which I can ascribe the principle of 

 generation, any more than there is in the brain anything dis- 

 coverable after sensation and experience, which are the prime 

 sources of art, and when I find the structure of both alike, I 

 have devised this fable. Let learned and ingenious men con- 

 sider of it, let the supercilious reject it, and those who are 

 peevish and scoffing laugh if they please. 



Since, then, nothing can be apprehended by the senses in 

 the uterus after coition, and since it is necessary that there be 

 something to render the female fruitful, and as this is probably 

 not material, it remains for us to take refuge in the notion of 

 a mere conception and of " species without matter" (species 

 sine materia), and imagine that the same thing happens here 

 as every one allows takes place in the brain, unless indeed 

 there be some one " whom the gods have moulded of better 

 clay," and made fit to discover some other efficient cause be- 

 sides any of those enumerated. 



Some philosophers of our time have returned to the old opinion 

 about atoms, and so imagine that this generative contagion, as 

 indeed all others, proceeds from the subtile emanations of the 

 semen of the male, which rise like odorous particles, and 

 gain an entrance into the uterus at the period of intercourse. 

 Others invoke to their aid incorporeal spirits, such as demiurgi, 

 angels, and demons. Others regard it as a process of fermenta- 

 tion. Others devise other theories. I pray, therefore, a place 

 for this conjecture of mine until something certain is esta- 

 blished in the matter. 



Many observations have been made by me which would easily 

 overthrow the opinions I have mentioned, so easy is it to say 

 what a thing is not rather than what it is ; this is not, how- 

 ever, the place to introduce them, although elsewhere it is my 

 intention to do so. On the present occasion I shall only ob- 

 serve, if that which is called by the common name of " con- 

 tagion," as arising from the contact of the spermatic fluid in 



1 Metaphys. lib. i, cap. 2. 



