156 LOUIS PASTEUR. 



suspended only by their false feet. The few moths which 

 have succeeded in piercing their cocoons do not show 

 any corpuscles. They can produce eggs, but these 

 eggs, coming from parents weakened by disease, give 

 rise the following year to a generation threatened 

 with flacherie. It is in this sense that the disease 

 may be regarded as hereditary, although the para- 

 sites of the intestinal canal to which flacherie is due 

 do not transmit themselves to the eggs or to the 

 worms which issue from them. The worms inherit 

 weakly constitutions, and, being without power of 

 resistance against anything that can derange their 

 digestive functions, they are at the mercy of the 

 accidents of their culture. 



Too large an assemblage of worms in one nursery ; 

 too high a temperature at the tune of moulting; a 

 thunderous atmosphere, which predisposes organic 

 matter to fermentation ; the use of heated or wet 

 leaves, especially if the wetting be caused by a fog or 

 by the morning or evening dew, which deposits on the 

 leaf the germs suspended in a great mass of ah-; these 

 are so many causes calculated to diminish the activity 

 of the digestive functions of the worms, and to produce 

 in consequence a fermentation of the leaf in the in- 

 testinal canal the malady now under consideration. 

 Often also flacherie depends upon mistakes committed 

 by the husbandman while tending his precious ' kine,' 

 to use an expression of the sixteenth century. 



