94 REPORT OF THE AGRICULTURAL RESEARCH INSTITUTE 



Study of the life cycle of the parasitic organisnis- 

 (Nosema Bombycis) is being carried out; so far no marked 

 differences have been observed between the Indian and 

 European forms, but observations are necessarily incom- 

 plete at present. 



Indigo. At the suggestion of the Indigo Research 

 Chemist an enquiry was undertaken into the bacteriolo- 

 gical aspects of the fermentation taking place in the indigo 

 steeping vat. As might have been expected, many import- 

 ant facts in connection with the great variations in yield 

 which are known to occur for no obvious reason were 

 brought to light by this enquiry, which, however, has not yet 

 proceeded far enough to afford any complete explanation 

 of the results obtained. It is clear, however, that the suc- 

 cess of the process of manufacture as at present carried out 

 depends primarily upon the presence and action of specific 

 bacteria in the steeping vat, and further that in some cases 

 an adverse result is due to the activity and deleterious 

 influence of others. It is a well known fact thai during 

 the earlier days of manufacture the yield of indigo is low 

 but becomes rather suddenly higher, remaining so as long as- 

 continued use of the vats persists. Any vats not utilized 

 at first but brought into operation later, exhibit the same- 

 phenomenon, clearly showing that the latter is not due to 

 changes in the plant, the water, or methods of manufacture. 

 Well attested cases have been observed of differences in 

 yield of as much as one hundred per cent, or more between 

 head factories and their out-works manufacturing plant 

 grown under similar conditions of soil and climate, and it 

 was possible in one instance to arrange to exchange indigo 

 plant from one such factory to another, thus eliminating 

 any possible influence of this factor, but without altering 

 the previously observed difference in the respective yields. 

 The most obvious conclusion seems to be that such differ- 

 ences are due to the presence or absence of specific bacteria 

 which multiply in and infect the steeping vats, increasing 

 in number and consequently in their influence upon the cha- 

 racter of the fermentation up to the limits of the permanent 



