INSTITUTE, PUSA, FOR 1919-20 111 



fixing power of Azotobacter are being carried out. So far 

 it appears that these products appreciably lower the 

 amount of nitrogen fixation. 



Numerous colonies of actinomycetes have invariably 

 been found growing on Ashby's mannite agar plates, ino- 

 culated with a dilute soil suspension. Twelve species were 

 examined for nitrogen-fixing power. Only minute gains 

 were recorded, but as this group of organisms is one of the 

 most abundant in soil, their accumulated effect may be of 

 considerable importance, and further investigations of their 

 activities are being taken up. 



Seven soils, two from Pusa and five from Mysore, were 

 examined for nitrogen fixation under anaerobic conditions. 

 In liquid culture gains of up to 6-5 mgm. nitrogen per 

 gram dextrose were obtained. Sugarcane megasse has 

 proved an admirable medium for the growth of nitrogen- 

 fixing organisms. After inoculation with mixed cultures 

 of nitrogen-fixing organisms, its nitrogen content rose 

 from 0-27 per cent, to 1-3 per cent, in two months. 



IV. Indigo. 



Owing to the short rainfall and backward condition of 

 the plant no experiments in manufacture have been car- 

 ried out since those mentioned in the last report. 



Pure cultures of indican hydrolysing bacteria were 

 maintained in the laboratory; the culture In 10 , the most 

 efficient, isolated three years ago, has lost none of its effi- 

 ciency in that period. 



V. Sterilization of water. 



Investigations on this subject were continued, and sup- 

 plies of the sterilizer " E.C." were manufactured for the 

 weekly disinfection of the wells on the estate. 



Two to three per cent, of available chlorine was found 

 to be the maximum possible obtainable with economy of 

 current consumption, and in higher concentrations stability 



