142 



The Ohio Naturalist. 



[Vol. X, No. 6, 



noteworthv characteristic than structural deviations or acclima- 

 tization. Much economic value would attach to an extension of 

 these experiments by determining through selection and a more 

 detailed physiological study the cultivated forms resistant and 

 immune to the effects of this type of soil bacteria, and the nature 

 of the resistance. 



In order to determine the abilitv of the micro-organisms to 

 convert soluble proteids into amido-acids and allied products 

 from the decomposition of proteids enough peptone was added to 

 solutions of sterilized bog-water and peat to make an equivalent 

 of a 1% peptone culture. After sterilization the solutions were 

 inoculated with the bacteria indicated in Table III. The cul- 

 tures were then tested physiologically at the end of a two-weeks 

 incubation. Since the danger of contamination becomes 

 increasingly greater with peptone cultures, the transpiration 

 figures for only the first five days are tabulated. They are 

 believed to be entirely consonant with the true state of affairs 

 since the figures in the duplicate cultures appeared in every way 

 parallel. The wheat plants had grown in each experiment for 

 three days at the time the photographs here added were made for 

 the writer by Prof. Schaffner. 



TABLE III. 



Transpiration Data for 1% Peptone Culture Solutions Inoculated 

 Jan. 15, 1910, With Pure Cultures of Bog Bacteria. 



A brief inspection of the figures and the photographs su^ices 

 to show that transpiration, growth, green and dry weight of 

 wheat plants are in this case proportionallv reduced. Compared 

 with the weekly atmometer readings it is evident that transpira- 

 tion is not merely a function of absorption and of growth but also 

 a function of the rate of evaporating power of air, that is the 

 saturation deficiency of air. The rate of transpiration is seen to 

 be the product of a co-ordination of factors. It is not due to 

 any single factor but to the cumulative action of several 

 conditions. 



