THE TESTING OF HUMOGEN 137 



organism. No one cell is exactly the same as any 

 other cell, but the cell of any given tissue possesses 

 certain properties varying within limits round a 

 common mean. Some chemists believe that a 

 similar doctrine holds about the elements for 

 instance, that one atom of Nitrogen is not the same 

 as another atom of Nitrogen, but that the atoms 

 themselves have certain limits within which they, 

 too, are able to vary. 



The complexity of the living cell, and the conse- 

 quence of this complexity that cause and effect are 

 frequently masked has created considerable diffi- 

 culties in the researches connected with bacterized 

 peat. The problem of Nitrogen fixation by means 

 of bacteria in the case of leguminous plants had been 

 satisfactorily worked out in the laboratory some 

 years ago, and in his nitrobacterine Professor 

 Bottomley had obtained a form of culture which 

 gave satisfactory results. Tested a little prema- 

 turely, perhaps, under glass and field conditions, the 

 nitrobacterine gave several failures because various 

 factors that were eliminated successfully in the 

 laboratory upset the necessary conditions when the 

 bacteria were set to work on the land. Scientifically, 

 nitrobacterine was a success. As has been stated 

 previously, the American Board of Agriculture 

 during the last few years has studied these field diffi- 

 culties, and is now using a preparation similar to the 

 nitrobacterine that in this country was too hastily 

 condemned by many who failed to get results. 



One of the essential difficulties in connection with 

 the old material was to insure that the bacteria, 



