76 REPORT ON THE DISEASES OF SILKWORMS IN INDIA 



lucence so that gattine and lucettes orsalpha are practically the 

 same thing. According to Pasteur there are only four silkworm 

 diseases — pebrine, muscardine, flacherie and grasserie — and all 

 these various disorders of the gut are to be referred to varieties of 

 flacherie. They are evidently all brought about in much the same 

 way and the course of the disease leads to the same results — the 

 death and putrefaction of the animal. Gattine is stated to attack 

 the silkworm in its earlier stages — unlike flacherie which usually 

 shows itself after the fourth moult. A peculiar feature is said to 

 be the growth of the hooks on the prolegs,*so that these become 

 extremely long and cause the larva to cling strongly to whatever 

 it crawls over (Banks, 1911). 



As far as my experience goes, I have never found worms in the 

 young stages attacked, nor have I found the peculiar development 

 of the hooks on the prolegs. Many of the worms kept in the hot 

 moist chamber, however, showed symptoms of what might doubt- 

 less be called salpha, but between these and the most typical 

 flacherie cases there were many intermediate forms. The trouble 

 was evidently caused by the same factors, so that I do not feel 

 inclined to admit it as a separate disease. I prefer to adhere to 

 Pasteur's classification of four diseases — all these other " diseases " 

 being merely varieties or combinations of the original four. 



(c) Rasa (Jaundice or Grasserie). „ 



Definition and diagnosis. Here again we have to deal with 

 a very well marked disease. It attacks worms as a rule towards 

 the end of the larva life — rarely before the third moult, usually 

 after the fourth. The worms attacked are restless, bloated in 

 appearance and yellow in colour. The skin is frequently shiny 

 and is very easily torn. The blood is turbid instead of clear, and 

 when examined under the microscope it is found to be full of minute 

 polyhedral crystalloids. These bodies may be found in all organs 

 of a diseased caterpillar. They are formed in the nuclei of the 

 cells, chiefly of the fat body, and are the result of degeneration 

 which may be brought on in several ways. 



Polyhedral bodies are transparent and brittle, so that they may 

 be crushed by pressing on the cover-slip. They are not very easily 

 stained, but may be coloured with such dyes as carbol-fuchsin or 

 picric acid. They are very resistant to such reagents as acids, 

 weak alkalies, chloroform, ether or alcohol. 



An excellent account of these crystalloids and jaundice in 

 general is given by Sasaki (1910), to whose work I am indebted 

 for much information. 



