386 ANIMAL REPRODUCTIONS. 
immediate than when the newt is old, as the 
Abbé Spallanzani has already obferved, and as I 
myfelf have feen. ‘Phe reafon is evident ; for 
the younger an animal is, the more ductile or 
pliant are its folids, becaufe their fluids are more 
abundant. — Irritability has alfo greater energy in 
young animals, becaufe they are more  gelati- 
nous. We have feen in the Memoir on the re- 
produdtion of fnails, that a confiderable time is 
neceflary before the new part becomes perceptible. 
The feeond fact demonftrated by my experi- 
ments, refpects the firft appearance of the mem- 
bers. A conical papilla arifes, which, compared 
to a vegetable bud, we may call an animal bud, 
But the comparifon muft be extended no farther, 
for the vegetable bud is properly only the en- 
yelope of a plantula, whereas this animal bud is 
the member itfelf, infinitely contracted in minia- 
ture. ‘The faét is evinced, by attending to the 
progrefs of evolution. The fummit of the pa- 
pilla divides in two, and we immediately difcover 
that divifion is produced, by the feparation of 
two fingers, formerly united or confounded to- 
gether in the fame organic mafs ; the ‘like enfues 
with all the fingers, which fucceflively appear. ~ 
The papilla is therefore.a real hand, or foot, al- 
ready formed ; but the concentration, minute- 
nefs, and tranfparency, prevent it from being re- 
cognifed in its original ftate. Yet it muft be ob- 
ferved,. 
