154 MICROBES, FERMENTS, AND MOULDS. 



creosote or carbolic acid, which do not affect the silk- 

 worms (Bechamp), 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 

 marts-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 

 a glass of water and left to putrefy 

 <* (Fig. 73). In a healthy specimen, 



O^ 



of good digestion, these bacteria 



are never found ' li is therefore 

 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 



