114 



Litmus. 



For tests made with litmus see under Reduction experiments and 

 in various other parts of this paper. 



REDUCTION EXPERIMENTS. 

 Methylene Blue. 



The reducing^ tendencies of Ps. hyacinthi and other organisms were 

 tested on methylene blue in Dunham's solution (1 per cent peptone and 

 0.5 per cent sodium chloride in distilled water). To each 100 c. c. of 

 the Dunham's solution, which was made from Witte's peptonum siccum, 

 was added 2 c. c. of a solution of 50 mg. of methjdene blue in 50 

 c. c. of distilled water. The results obtained are expressed briefly in 

 the following table, each organism grew in the medium, but as there 

 was no repetition of the experiment some of the statements ma}^ be sub- 

 ject to revision: 



Table VII. — Effect of Fs. hyacwthi, etc., on methylene blue in salted j)eptone water. 

 Experiment begun March 21. Color of fluid, bright blue. 



