REPORT ON THE DISEASES OF SILKWORMS IN INDIA 13 



to rear half as many worms again as 10 years previously, without 

 any proportional increase of accommodation, the industry was over- 

 taken with disaster. The parasite, always present in some worms, 

 increased to an appalling extent, destroying the worms wholesale, 

 and the industry came near to perishing. This is the only detailed 

 account, as I have said, of a pebrine epidemic, but it is interesting 

 to note that Lefroy (1916) in his report draws attention to the 

 fact that " pebrine is supposed to have become serious about the 

 time (1875) that prices were falling heavily": when this occurred 

 " the rearer strives to cut down expense, and to increase his 

 brood." " I think we may assume that the rearer, in the years 

 of falling prices, probably brought out the pebrine epidemic 

 by bad feeding and directly brought on the condition that ruled 

 for some years." That, I believe, is a true statement of the 

 case. Pebrine is nothing new, but under ordinary conditions the 

 parasite does not assert itself so that its presence is overlooked. 

 As soon as the rearer deviates in the slightest from the best practice 

 of rearing, the parasite goes ahead, and an outbreak of pebrine is 

 the result. 



I have somewhat, insisted on this point because it seems to me 

 that in India there has been a tendency to look upon pebrine as 

 something new, and as such something that may at any moment _ 

 assume very serious proportions. This view appears to me quite 

 wrong. The disease is not a new one, and under the present Indian 

 conditions it is not likely to become any worse than it has been 

 during the past forty-six years — the period fixed by Mukerji since 

 its assumed appearance in Bengal — or during the unknown and 

 unnumbered years that have passed since its actual origin. There 

 is no call for alarmist statements. The parasite of the disease is 

 present in India and probably, has been for a very long time. In 

 the past it has probably — almost certainly about 1875 — assumed 

 epidemic form when economic conditions were such as to induce the 

 rearers to depart from their customary practices, and in the future 

 it is likely to behave in the same way. As we shall see later, they 

 have a worm to rear that is very hardy and is accustomed to the 

 minimum amount of food. They cannot well under-feed or over- 

 crowd more than they do at present, so that on the whole it is 

 probable that things will remain much as they are. Eearing condi- 

 tions will stay the same, so that the balance which has been 

 established between parasite and host will not be greatly disturbed, 

 and we are not likely therefore to have any serious outbreak : it is 

 not to be expected that " its future spread and expansion to dimen- 

 sions similar to those attained in France in the middle of last century 

 is only a matter of time." While wishing to stop once and for all 

 exaggerated ideas about pebrine, I do not intend to minimize the 



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