28 



in form, and cottony in texture. They can not be unreeled, but must 

 be carded or combed out, and consequently are far l?.ss valuable than 

 singfle ones. 



In storing- cocoons care should be exercised to protect them from 

 rats and mice, which are very destructive to them. Ants occasionally 

 do some damage, and the larvse of the little beetle commonly known 

 as the "museum pest" will gain a foothold whenever possible. Jar- 

 bon bisulphid will usually dispel these two latter pests. 



Cocoons may, if thoroughly dried, be placed in cloth bags and sent 

 by mail, no bag to weigh more than 4 pounds gross weight. It is 

 always risky to ship "green" or partly green cocoons in any manner, 

 either by express or mail. The crushing of thoroughly dried cocoons 

 in transit does not injure them for reeling purposes. 



DISEASES OF SILKWORMS. 



In every successful rearing of an ounce of eggs about 40,000 worms 

 are hatched, and 30,000 succeed in spinning cocoons. The rest either 

 die from casual wounds or from diseases incidental to restricted action. 

 But sometimes whole chambers are destroyed by hereditary and con- 

 tagious diseases, and it^s of supreme importance to cultivators to learn 

 how these scourges may be avoided. 



In this limited treatise only a bare mention can be made of the most 

 fatal diseases and of the necessary precautions to be taken to guard 

 against them. The general cause of disease is the domestication of 

 the worm. By using good eggs, however, and following the methods 

 which are actually employed by successful rearers, remunerative results 

 are usually obtained. To obtain good eggs it is necessar}'^ to adopt new 

 methods. These are chiefly such as involve the use of the microscope. 



Among the many diseases of silkworms, the principal ones are: 



Pebrine, flacherie or flaccidity, gattine or macilenza, calcino or mus- 

 cardine. and grasserie. 



FEBBINE. 



This disease was first noticed in epidemic form in France in 1845. 

 Since then it has appeared in Italy, Spain, Portugal, Turkey, Turkes- 

 tan, the Caucasus, Kashmir, China, and Japan, threatening to destroy 

 the silk industry. 



Between 1833 and 1865 the annual crop of cocoons in France was 

 reduced by pebrine from 57,200,000 pounds to 8,800,000 pounds. No 

 remedy has been found for the disease, but the Pasteur microscopical 

 selection of eggs, insuring the birth of healthy worms, is a sure prevent- 

 ive. The universal adoption of this method has made pebrine almost 

 a thing of the past; and following Pasteur's line of research, means 

 have now been discovered for avoiding every kind of silkworm disease. 



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