410 ON GENERATION. 



not in act. Precisely as from the same rain plants of every kind 

 increase and grow ; because the moisture which was a like power 

 in reference to all, becomes actually like to each when it is 

 changed into their substances severally : then does it acquire 

 bitterness in rue, sharpness in mustard, sweetness in liquorice, 

 and so on. 



He explains, moreover, what parts are engendered before 

 others, and assigns a reason which does not differ from the 

 second basis of Fabricius. " The cause by which, and the cause 

 of this cause, are different ; one is first in generation, the other 

 in essence ;" by which we are to understand that the end is 

 prior in nature and essence to that Avhich happens for the sake 

 of the end ; but that which happens for the sake of the end 

 must be prior in generation. And on this ground Fabricius 

 rightly infers that all those parts which minister to the vegeta- 

 tive principle, are engendered before those that serve the sen- 

 sitive principle, inasmuch as the former is subordinate to the 

 latter. 



He subsequently adds the differences of those parts which 

 are made for some special purpose : some parts, for example, are 

 instituted for a purpose by nature, because this purpose en- 

 sues ; and others because they are instruments which the pur- 

 pose employs. The former he designates genitalia, the latter 

 instrumenta. For the end or purpose, he says, in some cases, 

 is posterior, in others prior to that which is its cause. For 

 both the generator and the instruments it uses must exist an- 

 teriorly to that which is engendered by or from them. The 

 parts serving the vegetative principle, therefore, are prior to the 

 parts which are the ministers of sense and motion. But the 

 parts dedicated to motion and sensation are posterior to the 

 motive and sensitive faculties, because they are the instruments 

 which the motive and. sensitive faculties employ. For it is a law 

 of nature that no parts or instruments be produced before there 

 be some use for them, and the faculty be extant which employs 

 them. Thus there is neither any eye nor any motive organ 

 engendered until the brain is produced, and the faculties pre- 

 exist which are to see and to govern motion. 



In like manner, as the pulsating vesicles serve as instruments 

 for the motion of the blood, and the heart in its entire struc- 

 ture does the same, (as I have shown in the work on the Mo- 



