OTHER DISEASES OF DOMESTIC ANIMALS. 155 
ferments. of unhealthy silkworms do not suffice to 
destroy the bacteria of the leaves, nor to neutralize 
their injurious effects. 
These bacteria are really the cause of the disease, 
for if even a minute quantity of the leaves taken from 
the intestine of diseased silkworms be given to healthy 
specimens, they soon die of the same disease. It is, 
therefore, essentially contagious, and in order to prevent 
the diseased silkworms from contaminating the healthy 
by soiling the leaves on which the latter are about to 
feed, as much space should be assigned to them as 
possible. 
Good seed should also be selected, since it has been 
ascertained that some lots of seed are more liable to 
the disease than others. The affection does not indeed 
begin in the egg, as in pebrine, but the question of 
heredity comes in. It is clear that when a silkworm 
has been affected by flacherie without dying of it, its 
eggs will have little vitality, and the grubs which issue 
from them will be predisposed by their feeble constitu- 
tion to contract the disease. 
