HOW PBRINE WAS STAMPED OUT 229 



bycis were present in either parent, the remains of 

 the parents and the whole of their progeny were 

 burned. Drastic as this may seem, it was found to 

 be the only means of stamping out the disease ; for 

 often the grubs that were born infected would grow 

 well until about to spin, and then extensive mortality 

 would set in and the colony perish miserably. The 

 parasites in these cases remained latent in the bodies 

 of the larvae for very long periods, but assumed great 

 activity at the time of stress of the host, such activity 

 bringing about not only its own propagation by spore 

 formation, but also the death of its host. Other 

 silkworms which fed in the neighbourhood of an 

 infected larva ate food soiled by the diseased one, 

 and, such food being contaminated with spores of 

 N. bombycis, they, too, fell victims to the disease. 

 Both the hereditary and the contaminative methods 

 of infection occur with N. bombycis. At present, 

 the latter method, with many variations in its 

 execution, seems to be the only one for the spread 

 of N. apis. 



The dissemination of the spores of N. apis, the 

 only stage proved capable of infecting new hosts, is 

 not only of economic importance, but also presents 

 an interesting example of the reflex of the individual 

 on the life of the community. 



It was earlier mentioned that the infected bees 

 endeavoured to the last to fulfil their allotted tasks 

 within or without the hive, and died in the attempt 

 to continue their duties. The faeces voided by such 

 infected bees have been recovered from honey, pollen, 

 and wax in the hive, and from the foliage and flowers 



