154 MICROBES, FERMENTS, AND MOULDS. 
creosote or carbolic acid, which do not affect the silk- 
worms (Béchamp), and which hinder the development 
of microsporidia. These fumigations likewise keep 
the litter from becoming corrupt, and in a properly 
conducted nursery the litter is kept dry. 
Flacherie—Wrongly confounded with pebrine, the 
disease flacherie is still more destructive to silkworms. 
The symptoms are remarkable. The rearing of silk- 
worms often goes on regularly up to the fourth moult, 
and success seems assured, when the silkworms suddenly 
cease to feed, avoid the leaves, become torpid, and 
perish, while still retaining an appearance of vitality, 
so that it is necessary to touch them in order to ascer- 
tain that they are dead. In this state they are termed 
morts-flats. A few days, sometimes even a few hours, 
suffice to transform the most flourishing nursery into 
a charnel-house. 
Pasteur examined these morts-flats, and found that 
the leaves contained in the stomach and intestine were 
full of bacteria, resembling those which are developed 
when the leaves are bruised in 
eae ee a glass of water and left to putrefy 
‘eo* - & oo (Fig. 73). In a healthy specimen, 
% fe of good digestion, these bacteria 
ME ae (Gann. Flachere are never found. It is therefore 
microbe (x 600 dlam.). evident that the disease is owing 
to bad digestion, and becomes rapidly fatal in animals 
which consume an enormous amount of food, and do 
nothing but eat from morning to night. The digestive 
