22 
THE ART OF REARING 
I shall mention these breeds and varieties in the 
due course of this work. (Chap. XI.) 
I must here observe, that although the silk- 
worm is with us in a very different climate from 
that in which it originated, and though it is domes- 
ticated, yet that we have clear proof, (Chap. V. 
VI. VII.,) its constitution is sound and vigorous, 
capable of often resisting the severe trials made 
on it by error and ignorance. Still we sometimes 
see whole broods of these insects fail in a short 
period, and others lose much in quantity and 
quality by want of cax*e. (Chap. XII.) It has been 
said, that in Asia they obtain as many as twelve 
crops of cocoons in a year. And some person made 
experiments, and published some views on the 
subject, stating, that with us there might, at 
least, be gathered two crops. My experiments on 
the contrary tend to prove, that it would be a 
sure method of destroying the mulberry-trees, 
and consequently the entire breed of silk-worms. 
I cannot, indeed, bring myself strictly to believe, 
that in Southern Asia it should be possible to 
have such numerous crops of cocoons. 
The southern part of China corresponds very 
nearly", as to climate, with the southern parts of 
Persia ; and yet there, according to the illustrious 
Pallas, the boughs of the mulberry-trees are cut 
only twice in the year, so as to have in the same 
year two crops of cocoons. 
