hi M. DoiDGE 75 



Pigment production has been described in various media in connection 

 with the cultural characters of the organism. The pigment is insoluble 

 in water (hot and cold), alcohol, ether, chloroform, carbon bisulphide 

 and dilute acids and alkalis. 



Reducing agent formation. 



Colour reduction. The reducing power of the bacillus is very shght ; 

 it was tested in nutrient broth tinted with various coloured solutions. 

 Rosolic acid and indigo carmine are not reduced. Methylene blue 

 becomes peacock green in two days and in five days is completely 

 reduced. Neutral red which was at first flame scarlet in four days 

 was reduced to orange bufT but was completely reduced only at the end 

 of 15 days. 



Litmus showed no sign of reduction until after 15 — 21 days when 

 there was a small amount of colourless liquid at the bottom of the tube, 

 after a few days the colour again became even. 



Reduction of nitrates. In nitrate broth the nitrates are reduced 

 with evolution of gas, the evolution being most vigorous at 25° C. 

 from the second to the fourth day, on the fifth day it ceased. The 

 tubes were tested at the end of the tenth day and gave no reaction 

 for nitrate or ammonia. 



In nitrate peptone water no gas is evolved and after 10 days the 

 solution gives positive reactions for both nitrates and ammonia. 



In control tubes both tests were negative. 



Gas production. No gas is evolved in fermentation tubes containing 

 bouillon or peptone water and any of the substances mentioned in con- 

 nection with acid production. The organism grows in the closed end 

 of the fermentation tube but frequently the clouding is only slight. 

 In iron peptone and lead peptone solution there was a distinct blacken- 

 ing of the precipitate as compared with the control tubes; a small 

 amount of sulphuretted hydrogen is therefore present. 



Atmosphere. The organism is a facultative anaerobe, as suggested 

 by its ability to grow in the closed end of the fermentation tubes. 



Four sets of cultivations were prepared, one of which was sealed 

 in Buchner's tubes containing an alkahne solution of pyrogalhc acid, 

 and the other three were each placed in a Bulloch's apparatus. 



From the first the air was exhausted as completely as possible so 

 that the organism was growing under reduced pressure; from the 

 second the oxygen was absorbed by pyrogallic acid, and the air in the 

 third was displaced by COg. 



