254 
THE ART OF REARING 
3. When care is taken to keep the eggs in the 
cloths on which they were deposited in the propor- 
tion of one ounce upon a space three feet square 
of surface. 
4. When the cloths on which are the eggs 
are not folded too often, not above six or eight 
times double, and are hung on the frames which 1 
described. 
2. Diseases which attack Silk-worms when the 
Rules I have prescribed for hatching the Eggs 
have not been strictly adhered to, although the 
Eggs were good and well preserved. 
These diseases, numerous and fatal, occur, — 
1. When the embryo, just verging toward its 
transformation into the worm state, in a moderate 
temperature, is suddenly exposed to a much higher 
temperature. Its developement is forced, its or- 
gans decomposed, and the cocoon of the worm, in- 
stead of a deep chestnut, appears more or less red, 
which is a certain sign of alteration and future 
disease. 
2. When on the point of transformation into 
the worm, the embryo is suddenly exposed to a 
lower temperature. The damage is then pro- 
portioned to the length of time the exposure 
acted upon the embryo ; it is extreme if it has 
lasted many hours. 
3. When the silk-worms, being just hatched, 
