18 BOTANICAL GAZETTE [JULY 
was made with equal parts of sulphanilic acid and napthylamine 
solution. 
The presence of ammonia was tested with Nessler’s reagent. 
The reaction is stronger in stations VII and X than in any other 
station. A faint test is obtained in station IX. Nitrogen gas 
is produced from nitrates in stations VII and VIII.” 
Before summarizing the facts brought out in the culture studies, 
there is need of mentioning another matter. A knowledge of the 
morphology of the simple form of organisms does not suffice to 
differentiate the numberless more or less similar species. It is 
difficult and almost impossible to identify a distinct and constant 
type for each species, or recognize form-differences suitable for 
classification. Nor does it seem that culture methods have made 
possible systematic grouping, or the variety of tests needed for 
accurate and trustworthy comparisons. No necessity exists for 
doubting the value of cultural characters; it is merely maintained 
here that additional and new methods must be tried, and tests 
should be scrutinized from every standpoint. Though widely 
different in their behavior in culture media and in their relation 
to air, yet the pathogenic properties of the bacterial flora from 
the different plant formations and societies should be ascertained 
within the limits of their natural habitat, and should be deter- 
mined also with reference especially to the degree of functional 
inhibition on higher plants. It is not until a study is made of the 
special reaction of bacterial transformation products in sterilized 
bog water upon the growth of agricultural plants that the lack of 
salient features between habitat relations and physico-chemical 
reactions in artificial media becomes noticeable. Considerable 
difficulty was experienced in the isolation of organisms with the 
conventional media. In the majority of cases very little growth 
was obtained on beef broth gelatin or agar. Gelatin and agar 
media made with peat and bog plant juices proved more satis- 
factory for isolation purposes. Moreover, bacteria of rapid 
growth and early appearance of colonies on the artificial media 
2 Since the observations herein recorded, the writer saa through the courtesy 
of Professor HARSHBERGER a paper published by Dr. D. Rivas on “Bacteria and other 
fungi in relation to the soil” (Univ. Penn. Publ. 3:243- ee 1910). It is cited 
here as bearing directly on the problem in hand. 
