REPORT ON THE DISEASES OF SILKWORMS IN INDIA \\ 



safely assumed that pebrine has been in existence in Europe for 

 over three hundred years. Vlndeed, Pasteur was inclined . to the 

 belief that certain serious epidemics which in the end of the 17th 

 century, in 1750 and again in 1780 threatened to exterminate the 

 silkworm in France had been outbreaks of pebrine. Now if pebrine 

 has been a recognized disease of silkworms ever since their intro- 

 duction into Europe or at all events ever since men of intelligence 

 took a sufficient interest in sericulture to write treatises on it, is 

 it likely that the East — the home of the silkworm=~sh*ould be free 

 from this disease ? To my mind the matter admits of no doubt : 

 pebrine is no more a new disease in the East than it is in the West. 

 The fact that we have no early records of it in the East is not to be 

 wondered at, for there are no writings of any such description on 

 sericulture in India. The work was and is in the hands of illiterate 

 peasants, and the mind of the educated and intelligent inhabitant of 

 the country does not at present and doubtless did not in the past 

 run, as a rule, to biological investigations. 



But even for the Far East we have direct evidence that pebrine 

 was in existence at least ten years earlier than 1 875. Pasteur showed 

 that seed got from Japan in 1865 was infected with the disease. 

 So the Far East was not really free from pebrine, although Japan 

 had had that reputation : it required only a careful examination of 

 their stock to find it tainted. ,. The worms of the Near and Middle 

 East had by that date shown themselves to be highly diseased. Is 

 it likely that India out of all countries in the world should be free ? 

 The idea is preposterous. 



But indeed actual evidence of the presence of pebrine in India 

 prior to 1875 is not wanting. In a paper by Captain Hutton dated 

 November 1859 (See Geoghegan, 1880, page 113), the description 

 given of diseased "Boro poloo " eggs is obviously that of a pebrinised 

 laying. On the same page, too, mention is made of the " black 

 spots appearing at the junction of the annotations of the body." 

 A disease in Mysore which was described as " a sort of atrophy " 

 in 1866 was also doubtlessly pebrine. 



Significant, if indirect, evidence of the comparative antiquity of 

 pebrine is found in the history of the causal organism. As will be 

 seen below, this organism, Nosema bombycis, is a member of an order 

 which characteristically parasitizes insects. As far back as 1851, 

 when the group first began to be studied, all sorts of insects, includ- 

 ing several caterpillars, were found to be infected with the same 

 or very nearly related parasites. Here then we have a well denned 

 group of parasites commonly found in insects, and it is actually 

 claimed that the fact that it was not noticed in silkworms in India 

 prior to 1875 proves that it has been " introduced " in the country 



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