164 Decomposition of Cellulose 



dioxide and the other which appears to rely on the most resistant carbo- 

 hydrate, should exhibit this pronounced intolerance of soluble organic 

 compounds. 



General Aspects of the Cultivation of S. cytopiiaga. 



Mention has already been made of some early attempts to secure 

 elimination either of the thread or of the sporoid form of the organism 

 by means of differential treatment. Although the object of the experi- 

 ment was not achieved, the data thus obtained possess a few points of 

 cultural interest. They relate to the effect of (a) reaction of the medium, 

 (b) temperature, and (c) disinfectants. 



Relations to reaction of the medium. Two series of experiments have 

 been carried out, and the results secured indicate a fairly wide range of 

 resistance to acid and alkaline conditions. The gradations in the reactions 

 of the two sets are not identical and this is reflected in a certain amount 

 of divergence in the results. In the first series there appears to have been 

 reluctance to grow in concentrations exceeding N/80 acid and N/160 

 alkah; in the second series a tolerance was found ranging from N/50 

 acid to N/55 soda or, expressed in the terms in common bacteriological 

 use, from — 2° to + 2°. In view of the fact that hquid, and not solid, 

 medium was employed, this range of resistance is somewhat noteworthy. 



Table X. 

 Influence of the Reaction of the Medium on Groirlh. 



K faction of the culture solution 



HCl NaOH 



N/20 N/40 N/80 N/160 N/320 N/640 N/640 N/320 N/160 N/SO N/40 N/20 



+ ++ ++ ++ ++ ++ + + 



N/25 N/50 N/100 N/1.30 N/300 N/720 N/800 N/160 N/100 N/55 N/25 



-+++ ++ + + ++ + + + + + + + + ++ - + 



An approximately neutral reaction of the nutrient solution may, of 

 course, be secured by the addition of calcium or magnesium carbonate, 

 between the respective values of which there is little difference, but 

 general experience shows that in the presence of these compounds the 

 breakdown of the cellulose is less apparent than when the reaction of 

 the medium is due to alkaline carbonates. 



Relations to temperature. The incjuiries under this head are divisible 

 into two distinct lines, viz. the determination of (1) the optimum 



