6s SEMINAL VERMICULI. ie 
fpermatic vermiculi. on pafling from. without 
to the femen, fince their aliment is completely 
changed. It is not enough to fay, we have an 
example in the larve found in the horfe, the 
fheep, or the ftag, which live in a place where 
their exiftence did not begin; for I may anfwer, 
they have not paffed from a large to a little world 
after living in the former, but are developed in 
the quadrupeds where they have been depofited 
by their parent flies, where they remain until 
maturity, and feed on the fubftance of the ani- 
mal. If, before acquiring this maturity, their 
fituation was fortuitoufly changed, it is moft like- 
ly they would perifh. We fhould fee them perifh, 
or rather not expand, if the flies laid their eggs 
elfewhere. Whence it follows, that this exam- 
ple confirms the general law. 
If we cannot believe that vermiculi come from 
without, what is their origin? We fhall anfwer 
what Vallifneri has faid on the origin of the large 
worms in the human body.—They are produced, 
nourifhed, and multiplied in us and other ani- 
mals :—they pafs from generation to generation 
with the nutriment the mother affords in the 
uterus, or with the milk that is imbibed (1). ‘This 
hypothefis feems to me much more probable than 
the other. According to M. De Buffon, the fe- 
men 
(1) Vallifneri, T. 2, edition in folio, 
