STATES OF INSECTS. (lige.) 55 
the formation and development of the fatus in utero, of 
the chick in the egg, of the butterfly in the caterpillar, 
we in vain attempt fully to investigate; yet we can easily 
comprehend that pre-existent germes, by the constant 
accretion of new matter in a proper state, may be gra- 
dually developed, but we find it impossible to conceive 
how, by the action of second causes, without the inter- 
vention of the first cause, the butterfly should be formed 
in the caterpillar, unless it preexists there as a germe or 
foetus. ‘Is it not clear,’ 
manner, “‘as Blumenbach and other Physiologists main- 
? 
asks Dr. Virey in his lively 
tain, that there is a formative power, a nzsus_ formativus, 
which organizes the embryo? Admirable discovery !” 
says he, “which teaches us that the foetus forms itself 
because it forms itself! As if you should affirm that the 
stone falls beause it falls?!”” Had Dr. Herold considered 
what Bonnet says with as much good sense as modesty, 
he would never have imagined that his discovering the 
organs of the butterfly one after the other at certain pe- 
riods in the caterpillar, was any sound argument against 
their preexistence and coexistence as germes. ‘ Organs,” 
says that amiable and excellent Physiologist, “that have 
no existence as to us, exist as they respect the embryo, 
and perform their essential functions; the term of their 
becoming visible is that which has been erroneously 
mistaken for the period of their existence>.” ‘This has 
been Dr. Herold’s grand error: he mistook the com- 
a N, Dict. d Hist. Nat. x. 193. 
> Guv.v. 279. “II n’est pas exact de dire que le cceur, la téte, et 
la moelle épiniére, sont formés les premiers dans les fcetus des ani- 
maux A sang rouge et vertébrés,” says Dr. Virey; “ mais il faut dire 
seulement que tel est ordre dans lequel ces organes commencent a 
devenir visibles.’ N, Dict. d’ Hist. Nat. x. 196. 
