Ethel M. Doidge 4*27 



Flasks of nitrate bouillon tested after ten days contained slightly 

 more ammonia than similar flasks containing bouillon without potassium 

 nitrate. These tests were repeated several times with no more decided 

 results; it would seem therefore that the organism has a feeble action 

 on nitrates, and that traces of nitrite and ammonia are at times produced 

 in culture solutions containing a nitrate. 



Atmosphere. The organism is strictly aerobic and makes no growth 

 in the depth of media nor in the absence of oxygen. No growth took 

 place in Bulloch's apparatus in an atmosphere of hydrogen, nitrogen or 

 carbon dioxide, but except in the case of tubes exposed to C0 2 the 

 organism was not killed and began to grow when removed from the 

 apparatus and placed in the incubator. 



Temperature. This bacterium grows through a wide range of tem- 

 perature, it grows slowly at 5° C. and at 40° C; the optimum is about 

 30° C. It is killed by a prolonged exposure to 42° C. The thermal death 

 point (moist, ten minutes' exposure) is 56° C. ; in dry tubes the organism 

 did not grow after ten minutes' exposure to a temperature of 64° C. 



Reaction of medium. This bacterium does not grow at all in an alkaline 

 bouillon, even if only — 5 of Fuller's scale; it grows very slowly in bouillon 

 neutral to phenol-phthalein. It grows well in bouillon with a natural 

 reaction of + 25, the optimum being about + 20 of Fuller's scale; it 

 grows almost as well at + 15 as at + 20. A number of cultures were 

 also made in broth which had been made neutral and acidified with 

 various acids. It grew well in + 20 (Fuller), malic, lactic, tartaric, 

 hydrochloric and citric acids; in tubes with a reaction of + 25 Fuller, 

 it grew in tubes acidified with malic, lactic and citric acids and not with 

 tartaric or hydrochloric acids; it is much less sensitive to malic and 

 citric acids, growing unrestrainedly in bouillon with a reaction of 

 + 30 Fuller, and clouding bouillon up to + 50 Fuller, malic acid and 

 + 60 citric acid; the inhibition point for these was +55 and + 65 re- 

 spectively. 



Toleration of sodium chloride. Growth is inhibited by 4 per cent, of 

 sodium chloride; the organism grows freely in nutrient bouillon con- 

 taining 3 per cent, sodium chloride. 



Resistance to fungicides. Tests were made in nutrient bouillon con- 

 taining various percentages of copper sulphate, phenol, mercuric chloride 

 and formalin. Tubes were planted fairly heavily and after ten minutes 

 a plate was poured from each dilution. In this way the inhibition 

 coefficient and lethal coefficient were determined. 



The organism is killed by ten minutes' exposure to copper sulphate 



