CULTURE OF SILKWORMS. 13 



Silk Conimittee to a|>})ly the Pasteur system to the iniihivoltiue 

 worms, I will state here what my experience has been, the way 

 I have earried ovit the system and the plan which I propose for 

 adoption on a large scale. 



The moths on coming out of the cocot>ns are allowed tt) 

 pair, and in the evening are separated, the males being thrown 

 away and the females l)eing placed each in a small cone of paper, 

 one corner of which is then turned in so as to close its mouth. 

 These paper cones are strung up and the eggs laid in them. On 

 the fifth or sixth day after laying, the moths ai'e each taken and 

 crushed in little china cups with a glass pestle. A drop of the 

 tluid is transferred to a glass slide and a cover glass put over it. 

 These slides are then examined with a quarter-inch object glass 

 and high power eye-piece, giving a magnifying power of 630 dia- 

 meters. The eggs of all diseased moths are then destroyed, and 

 the healthy ones only reserved for breeding. On two occasions, 

 starting with highly pebriuised worms, I eradicated the disease 

 in from three to four generations by the above course of pro- 

 cedure. 



PROPOSED SYSTEM FOR PASTEURIZING 

 MULTIVOLTINE SILKWORMS. 



The selection, liy the microscope, of a large numlier of eggs, 

 in the way above described, is a commercial impossiliility, as there 

 are only six or seven working days between the laying of the eggs 

 and the hatching of multivoltine worms, instead of al>out as 

 many months in the case of the annual silkworms cultivated in 

 Europe. 



My plan for overcoming this difficulty is to maintain a breed 

 of say 3,000 worms, which for convenience may be called "firsts." 

 This breed is to be kept distinct and to be microscopically selec- 

 ted every brood. Our microscopist could examine all the female 

 moths of each In-ood of this number of worms, between the lay- 

 ing and hatching of the eggs. A certain number of the eggs from 

 the best cocoons would he jnit aside for the next generation of 

 " firsts," and the remaining eggs would be reared in se2)arate 

 houses, in which strict- sanitary precautions would lie maintained. 



This brood, which would not be microscopically selected, 

 may be called " seconds." On attaining maturity these " sec- 

 oncls " would lay, and it is their eggs which would be given to 

 the cultivators. 



They would therefore be always only once removed from 

 the "first" or microscopically selected eggs. If 1,200 female 

 moths out of the 3,000 above-mentioned were passed at a 



