INSTITUTE AND COLLEGE, PUSA, FOR 1910-11. 78 



REPORT OF THE IMPERIAL BACTERIOLOGIST 



FOR THE YEAR 1910-11. 



(C. M. Hutchinson, B.A.) 



The work of the Bacteriological Section during the past 

 year, the first during which it has been in operation, has 

 necessarily been largely confined to trial and selection of 

 the methods best adapted for dealing with the special condi- 

 tions of soil and climate obtaining in India. The biologi- 

 cal analysis of a soil not only involves a determination of 

 the number and kinds of bacteria contained in it and their 

 relation to the production of plant food, but must also in- 

 clude investigations having for their aim the discovery of 

 how such bacterial functions as make for fertility may be 

 encouraged and used to the best advantage in the ordinary 

 operations of agricultural practice. Hence the main lines 

 of work of this section have been aimed at determining 

 under what conditions various soils will best serve as cul- 

 ture media for those bacteria, naturally present in them, 

 upon which the processes of conversion of the organic nitro- 

 gen of humus into assimilable nitrates depend. 



Much preliminary work has been done in testing methods 

 already in use, and modifying them in accordance with the 

 requirements of local conditions. 



Special attention has been paid tu methods of plating 

 soils in such a way as to obtain information as to the num- 

 ber, kinds, and functions of the bacteria in them; this has 

 involved a study of media suitable for the purpose, and of 

 methods of inoculation, and this study is still in progress, 

 as it appears probable that each soil requires variation in 

 the composition of the medium in which it is to be plated, 

 in accordance with its chemical and physical character, 

 and with special regard to its previous agricultural history. 

 In soil platos made for the purpose of counting the num- 

 bers of bacteria present per unit volume or unit weight, 



