FUNGOUS VEGETATION IN SILK-WORMS. 



337 



cated by inoculation to the Chrysalis and the Moth, as well as to 

 the worm ; and it has been also obsei'ved to attack other Lepi- 

 dopterous Insects. A careful investigation of the circumstances 

 which favor the development of this disease, was made by Au- 

 douin, who first discovered its real nature ; and he showed that 

 its spread is favored by the overcrowding of the worms in the 

 breeding establishments, and particularly by the practice of 

 throwing the bodies of such as die, into a heap in the immediate 

 neighborhood of the living worms ; this heap speedily becomes 

 covered with this kind of "mould," which finds upon it a most 

 congenial soil ; and it keeps up a continual supply of sporules, 

 which, being diffused through the atmosphere of the neighbor- 

 hood, are drawn into the breathing pores of individuals pre- 

 viously healthy. Wherever the precautions obviously suggested 

 by the knowledge of the nature of the disease thus afforded by 



Fia. 120. 



Botrytis bassiana: — A, the fungus as it first appears at the orifices of the stigmata; E, tubuiar fila- 

 ments bearing short branches, as seen two days afterwards ; E, magnified view of the same ; c, d, 

 appearance of filaments on the fourth and sixth days ; r, masses of mature spores falling off the 

 branches, with filaments proceeding from them. 



the Microscope have been duly put in force, its extension has 

 been kept within comparatively limited bounds. The plant pre- 



22 



