118 ANIMALS AND VEGETABLES III. 
city, the moifture tranfpiring cannot diffipate, on 
the contrary, it falls back on the chryfalids. 
Thus, in feveral days, they appear moift, and the 
humidity infinuating itfelf into their bodies ren- 
ders them difeafed. Therefore, the death of 
chryfalids enfues nearly from the fame caufe as 
that of animals in ftagnant air. All this will pro- 
perly apply to the eggs of infects, and the feeds 
of plants. We know that eggs are not hatched 
until a certam degree of heat which promotes . 
perfpiration. Confined in a fmall veffel, they re- 
abforb the exhalations that had before tranfpired 
from them, and thefe corrupt. The humidity 
covering the eggs, and fometimes the fides of the 
veffel in confiderable abundance, proves it. The 
fame happens to vegetable feeds. I have often 
put them in clofe veffels, and, that they might 
germinate, in a little water. On taking them 
out, the part that had been expofed to the air 
was vifibly covered with a humid pellicle. 
For oppofite reafons, we fee why eggs and 
feeds are developed in large clofe veflels ; they 
are always in fafety, for the vacuity is fo great 
that the exhalations may difperfe. For the fame 
reafon do butterflies come from chryfalids when 
the veffels are capacious. 
OBSER- 
