766 
Journal of Agricultural Research 
Vol. V, No. 16 
The problem of this paper was a study of the effect of environmental 
factors upon this organism, especially as they influenced growth and 
reproduction. The experiments here reported verify the conclusions of 
Klebs and extend them for an untested group of organisms, the Sphae- 
ropsidales. As has been pointed out, in this paper the method of approach 
was different from the inductive methods used by Klebs in drawing his 
conclusions, since the methods employed here were deductive, based on 
our knowledge of the reactions of other organisms. The experiments with 
Plenodomus fuscomacidans give a method applicable to related forms. 
The results of this physiological work give a basis for practical recom¬ 
mendations as to the culture of other organisms, as well as evidence of the 
feasibility of developing a standard synthetic solution which would make 
possible a standardization of environments for diagnostic purposes. 
The action of light, when pushed to a last analysis and when con¬ 
sidered in view of the experiment in which hydrogen peroxid and other 
oxidizing agents replaced it, is seen to be of either an oxidizing or a 
catalytic type. This led to the development of a theory to explain the 
mechanism of the opposed action of growth and reproduction. This 
theory sees in the competition for oxygen the fundamental reason for the 
absence of fructification under conditions which allow abundant growth. 
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