1923] 



LEHMAN — POD AND STEM BLIGHT OF SOYBEAN 



163 



alkaline than at the start. Exclusive of No. 10, in which growth 

 was very irregular, these series recovered their original P H value 

 at the approximate time of attainment of maximum growth. 



Changes in titrable acidity in general follow change in hydro- 

 genion concentration. The P H value of the control flask for each 

 series remained stationary until the end of the experiment. 



Time In d«ye 



5 



10 



15 



«0 



25 



5© 



3t 



Fig. 13. 



Decrease of sugar in the culture solution was closely correlated 

 with increase of dry weight of mat. In fig. 13 the curves repre- 

 senting disappearance of sugar very closely follow those repre- 

 senting increase of growth. On the dates when maximum dry 

 weight of mat was found, sugar had entirely disappeared from the 

 culture solution. 



In a third experiment made for the purpose of testing the eff ec t 

 of hydrogen-ion concentration on pycnidial production, data were 

 obtained relative to the growth of Diaporthe Sojae on solid media. 



