UN! 



19 



slow growing dry white colony, which after weeks lines a cup-like 

 cavity with a thin dry spreading cream pink growth. No other 

 evidence of liquefaction occurs than the cup shaped depression. 

 Agar colonies are dry and shining to the eye; under low power 

 the edge is ragged, showing the individual rodlets pushing out 

 into the surrounding medium, Agar slant and potato show at 

 first a dry shining whitish layer, which later becomes "crusty", 

 wrinkled, and dull pink. Bouillon remains nearly clear, develop- 

 ment taking place in a thick surface pellicle of paraffin-like con- 

 sistency, from which flakes fall to the bottom of the tube on 

 shaking. Litmus milk, not coagulated, but shows intense alkaline 

 reaction and peptonization after a few weeks at 35 C. Aerobic, 

 non-gas producing, nitrates reduced to nitrites, slight growth at 

 37 C. 



B. rubropertinctus. 



In his experiments with acid-resisting organisms, Grass- 

 berger (74) made, in 1899, from butter and from guinea pigs inocu- 

 lated with butter, six isolations of the bacillus described below. 

 My culture, obtained from Krai in 1901, agress in biological 

 characters with Grassberger's original notes. As he gave it 

 no name, I have called it on account of its staining reaction, 

 B. rubropertinctus. 



Grassberger describes a 24 hours agar culture as showing 

 rods 1,53,0 ^ long, having no trace of acid resistance when 

 stained. Older cultures occasionally show longer bacilli, which 

 retain the stain slightly when treated with 3 % ac id alcohol, but 

 never evince the true tubercle bacillus reaction. I found that a 

 ten day potato culture, when stained on a cover glass together 

 with B. c o 1 i by hot carbol fuchsin , washed several times with 

 10 % H 2 S0 4 , and counter stained with methylene blue, resisted 

 the acid perfectly, remaining bright red in contrast to the blue 

 B. coli. The bacilli could not be mistaken for B. tuberculosis, 

 being much shorter and thicker. 



Gelatin plate shows characteristic colonies, the deeper ones 

 ovoid in shape and granular, ttye superficial colonies irregular, with 

 crenate edges, folded surface, and red color. Stab culture, slight 

 needle growth and orange red surface colony as above, no lique- 

 faction. Agar colonies, very slow, being just visible to the naked 

 eye in five days; uniformly granular, and irregularly triangular. 

 On agar slant, growth lustreless, dry, and spreading, later wrinkled 

 and vermilion red. Grassberger records one culture that was 

 moist. Potato development, slow but constant; at the end of ten 

 days orange red, rough, granular, and moist. Bouillon, clear save 

 for slight cloudiness at the top; a salmon pink pellicle is formed, 

 which is constantly renewed as it sediments on shaking. Litmus 

 milk shows no change except for the development of a pink pellicle; 

 B. rubro pertinctus is not gas-producing, grows at 37, is 

 aerobic. Grassberger notes slight indol production and cauli- 

 flower-like odor. My culture did not show these characters. 



