Qg REPORT ON THE DISEASES OF SILKWORMS IN INDIA 



later, are evidently similar to those that are said to cause flacherie 

 in univoltine worms and which were isolated from undoubted cases 

 of flacherie. It may be said that on the whole under ordinary 

 conditions multivoltine mulberry silkworms, just like univoltine 

 worms, are not readily, indeed hardly at all, infected with flacherie 

 by feeding them with the various bacteria which are supposed to 

 be the cause of the disease. Such evidence as we have does not 

 point to flacherie in India being a highly contagious disease or one 

 associated with any particular organism. 



An attempt was then made to try the effect of high tempera- 

 tures and humidity on worms fed on the various organisms — a 

 repetition of Sawamura's (1902-03) experiments. Unfortunately, 

 the lamp which was used for heating the chamber went wrong* 

 and the temperature of the chamber went up to such a height that 

 the worms all died off. This happened on the day of spinning 

 .so that the experiment was really not seriously interfered with — 

 if the organisms fed were going to prove pathogenic the effects 

 should have been shown before spinning. In one case — lot 1, Ex- 

 periment 26 — there was a very obvious onset of flacherie, nine out 

 of fifteen worms dying. These worms were fed on a mixed culture 

 ■of the three chief organisms isolated from cases of flacherie found 

 in Kashmir. When these organisms were fed separately three out 

 of six worms that had been fed on Bacillus A died ; two out of six 

 that had been fed on Bacillus C died ; none that had been fed on 

 Micrococcus a died. Bacillus A and Micrococcus a from Muga 

 worms and Bacillus B from mulberry moth were also tried. One 

 •caterpillar that had been fed on Micrococcus a died, showing small 

 numbers of Bacillus A in its gut. Here again I am able to con- 

 firm the results of the above-mentioned Japanese worker — high 

 temperature and humidity seem to be favourable conditions for 

 flacherie, and when certain organisms, notably Bacillus A, are fed 

 to caterpillars under these conditions flacherie appears to a very 

 considerable extent. 



It is to be noted that in the controls in the hot moist chamber 

 there was also considerable mortality, especially in lot 1. Here 

 the worms were put into the chamber before the 3rd moult was 

 begun, and numbers of the worms were unable to go through the 

 moult. When the 4th moult was entered upon all the remaining 

 control caterpillars, as well as those that had survived from the 

 fed lot, died — becoming flaccid and somewhat discoloured but 

 without exhibiting any great growth of bactdria in the gut. In 

 the controls of the other lots — lots 2 to 7 — two out o£ six cater- 

 pillars died showing external symptoms of flacherie. Thus, even 

 without the agency of any special bacteria, worms kept in an un- 



* This waB in the second experiment. The first attempt suffered no disaster. 



