ANIMAL REPRODUCTIONS. 405 
‘mention thefe monftrofities, becaufe they are not 
indifferent in the hiftory of reproductions. 
Experiment Vil. The reproductions of newts 
are retarded by cold.—It is well known how much 
the evolution of all organized bodies is’ promot- 
ed by heat: Animals vegetate like plants, and 
heat powerfully advances their vegetation. 
Thirty-feven years ago, experiments on polypi, 
and different fpecies of frefh water worms, de- 
monftrated that the reprodu@tion of thefe fingular 
animals was greatly retarded by cold. IF the 
mutilation was towards the end of autumn, and 
particularly if in winter, reproduction required 
feveral weeks ; and, on the other hand, it would 
‘be complete in a few days, in fummer. My ex- 
periments on newts confirmed the fa&@ in-a moft 
confpicuous manner, as will immediately appear. 
On the 6 of September 1777, 1 cut the arm 
and thigh off a large’newt, very near the body, 
and kept it in an apartment without fire until the 
month of January. Being then afraid of injury 
-from the cold, I carried it to my own chamber, 
along with other newts, which were the fubje& 
of various experiments. All pafled the winter 
fuccefsfully. The temperature of the chamber 
was commonly about 43° or 45°; but it fre- 
quently diminifhed 5° or 6° during night. 
@e 3 The 
