April, 1910.] 



The Bacterial Flora. 



M5 



and unproductiveness of soils. If attempted, the interpretation 

 would be indeed, one-sided; there is a co-ordination of factors, 

 each and all of which exert a relatively marked influence. Cli- 

 matic conditions, temperature, water, and air conditions in the 

 soil, as well as the phsycial and chemical character of it, and the 

 surface flora, all play an important role in determining the 

 character of a vegetation and of its bacterial flora, and therefore 

 also the character of the chemical products formed. 



One should constantlv keep in mind the genetic idea in the 

 study of edaphic, climatic, or biotic investigations. Soil, 

 climate and flora are the product of the conditions of their 



Fig. 2. Wheat plants growing in i per cent, peptone bog-water solutions 

 inoculated with pure cultures of bog bacteria. Numbers correspond with 

 data in Table III. 



development; their peculiarities are closely interrelated in the 

 dynamics of the process. Wherever the same factors are pres- 

 ent, the results will be similar. The bacteriological-chemical, as 

 well as the physiological method, deserve on that account a 

 closer consideration. The determination of the bacterial trans- 

 formation products and the more detailed study of their physio- 

 logical properties should possess an exactness and a reliability 

 to make them suitable for the solution not only of agricultural but 

 of ecological problems as well. It is only too clear that the need 

 for new investigations in this phase of the problem is pressing, 

 and that especially new points of view and new lines of research 

 are imperatively required. 



Botanical Laboratory, Ohio State University. 



