50 REPORT OF THE AGRICULTURAL RESEARCH 



Some work has been done on nitrogen fixation in certain 

 soil samples, but only of a tentative nature, fuller consi- 

 deration of the subject being postponed until such time 

 as my assistants have acquired more knowledge of bacte- 

 riological methods. It is proposed to make exhaustive 

 enquiries into the distribution and characters of nitrogen 

 fixing organisms in Indian soils, as it seems probable that 

 this source of nitrogen is of prime importance and may 

 even afford possibilities of control in actual practice, either 

 by actually supplying such organisms to soils in which 

 they are deficient, or, as the more hopeful means, by adopt- 

 ing methods of agricultural practice which would allow of 

 the fullest development of those already naturally present. 



Disease of Eri Silk Worms. — At the request of the Im- 

 perial Entomologist, a lengthy enquiry into the causes 

 producing a very high mortality amongst Eri Worms has 

 been undertaken, and is still in progress. The disease, the 

 symptoms of which resemble those appearing in Flacherie 

 of the Mulberry Worm, is associated with the presence of 

 a bacterium, pure cultures of which have been made from 

 the gut of diseased worms; attempts to establish the patho- 

 genicity of this bacterium for Eri Worms, bv Teeding with 

 leaf sprinkled with water shaken up with the cultures 

 have so far failed to give decisive results. From enquiries 

 made in Assam in the course of a tour undertaken with 

 the object of enquiring into this matter, it appears that 

 the disease, although known to native sericulturists, is 

 considered due to defective feeding and management and 

 not to be of the nature of an epidemic. Further experi- 

 ments will be carried out with a view to determining the 

 effect of varying food materials and feeding methods. 

 Numerous sections of the intestine of normal and diseased 

 worms were made by Mr. Shaw of the Mycological Section, 

 .showing the defective digestion characteristic of the disease 

 and the development of the bacteria in the gut. These 

 illustrate clearly ihe differences in the digestive processes 

 incident to the disease, but it is not certain whether the 

 increased number of bacteria is a cause or an effect of the 



