35 



same means of prevention and the same remedies when 

 they have occurred. It is therefore unnecessary to de- 

 scribe Jieir various symptoms, as it would lead to no good 

 practical result. 



The diseases of silk worms generally arise from the 

 want of sufficient air and space, from their not being kept 

 dry, and being fed with damp leaves, and also from their 

 not being kept sufficiently clean, particularly in the fifth 

 age. The fermentation of their litter, the dampness and 

 the bad air which it occasions, are the most frequent cau- 

 ses of mortality among them. The greatest care there- 

 fore should be taken to keep them constantly clean and 

 dry, and to give them a sufficient quantity of space and 

 air; a current of air in fine warm days, should always 

 be let into their nursery. If, notwithstanding all the care 

 taken, some general sickness should declare itself among 

 them, the remedy recommended by the writers, is, to give 

 them a change of air, by transporting them into another 

 room. But this may not always be convenient. It is 

 with these animals, as with our species, easier to prevent 

 diseases than to cure them. If nothing better can be done, 

 the diseased worms must be thrown away. The chloride 

 of lime and soda have been used with good effect in 

 some nurseries to cleanse the air. 



Before the worms begin to mount and spin their co- 

 coons, they void themselves of their excrements, and they 

 generally do it on or near the edge of the board on which 

 they are placed. Those who have not strength enough 

 to cast off their excrements/die in the attempt, and in the 

 morning numbers of them are found dead. They should 

 be carefully taken up and thrown away. When many 

 are found in that condition, it is a sign that the litter is 

 fermenting and that a cleaning is necessary. 



