H-A Silkworms in India. [ Vol 1. 



Vittadini, in 1859, founded bis system of selection, examining samples of eggs just at 

 the time of hatching aud rejecting those lots which showed the corpuscular disease. 



" At that epoch it was believed that the corpuscles existed even in the healthy 

 moth when well advanced towards its natural death, but Pasteur showed this 

 theory to be fallacious, proving, as we have said above, that the corpuscle is 

 only present when the moth is diseased. He showed that, where the moth is 

 free from the parasite, the egg too would be exempt, and that, as a rule, 

 where the corpuscles exist in the moth, there its issue will probably be corpus- 

 culous also. There is, to be sure, even then a chance of its purity, as mentioned 

 above, that is, when the corpuscles become abundant in the chrj'salis only after the 

 formation of the egg. But here, too, it is highly probable that the malady will have 

 so aflected the general health of the parent as to make her issue more apt to suc- 

 cumb to disease, as in the case of flaccidity. Therefore it is laid down as a rule, and 

 upon this rule the Pasteur s3 - stem of selection rests, that if, upon microscopical ex- 

 amination of the mother moth, the corpuscles of pebrine are found, then her eggs and 

 issue will also be pebrinous, and should be destroyed. 



"Flaccidity (Flacherie). — When after the worms have passed their fourth molt, 

 and are eating well and regularly, they have all the appearauce of perfect health and 

 vigour, and the silk-raiser feels'full confidence in the success of his crop ; some will 

 often be seen to crawl to the edges of the trays, and lie there languid and without 

 motion. But for the loss of their wonted activity aud the cessation of their naturally 

 voracious appetite, one would still think the worms in perfect health, for they yet 

 retain all the outward perfection of form that we have remarked above. In colour 

 they have, perhaps, become somewhat more rosy, especially if the disease is in a 

 violent form. On touching them, however, we find them soft, and even in this seem- 

 ingly live condition they are often dead. Had the worms been carefully observed at 

 this time, it would have been seen that the beating of the dorsal vessel was gradually 

 becoming slower, and that it finally, stopped altogether. A green drop appears at the 

 mouth, and the worm secretes a dirty liquid, which soils the anal orifice and gradually 

 closes it. 



" Before many hours are passed the skin begins to shrivel and draw in around the 

 fourth and fifth joints of the body, viz. those two lying between the set bearing the 

 legs proper and the set bearing the prolegs. Later, at this restricted point, the body 

 begins to turn brown, then black, and the whole worm is soon in an advanced state 

 of putrefaction. Then, and even before the death of the worm, a sour odour is 

 perceptible in the magnanerie, due to the fatty volatile acids exuded by the victims of 

 the disease. Should the malady strike the insects at a later period, when they are 

 ready to spin their cocoons, the same languishing air will be observed ; they will show 

 reluctance to crawl up into the arches, and will be seen to gather around their bases, 

 seeking some place, which it requires no exertion to attain, to spin their cocoon. Many 

 of those which reach the branches stretch themselves out motionless on the twigs and 

 die there. They are to be seen later hangiug by their prolegs in different states of 

 putrefaction. When these symptoms are observed, we may be sure that the worms are 

 attacked by flaccidity {flacherie). 



"A microscopic examination of the intestines of the silkworm will show masses 

 of undigested food, and the coats of the intestines will be found to be opaque. Here 

 too the microscope reveals the parasites ordinarily attending putrefaction, chief among 

 which is a bacillus seen sometimes with aud sometimes without a bright nucleus. 

 There also exists a special form of ferment, not unlike that which accompanies the 

 formation of vinegar (Mycoderma aceti, Pasteur), which is found in short chains, the 



