634 SUMMARY OF CURRENT RESEARCHES RELATING TO 



ture, with the formation of long threads composed of over fifty members. 

 It grows best on slightly alkaline medium (1 p.c. N) ; in litmus milk at 

 22° C. after 5 days it forms 1 p.c. N/10 alkali. It is pathogenic for 

 guinea-pigs when injected into the peritoneum. It produces a toxin 

 which can be extracted from the dead cultures, and which is fatal for 

 guinea-pigs in relatively small doses. 



Differentiation of the Human and Bovine Tubercle bacillus.* 

 Th. Smith finds that if these bacilli are grown in glycerin broth, titrated 

 against phenolphthalein to 2 p.c. normal acid, during the first two weeks 

 both cultures tend more and more towards the neutral point, but later 

 the culture of the human bacillus, which has become about 0*3 p.c. 

 acid, again becomes more acid, and eventually regains its original 

 reaction ; whereas the culture of the bovine tubercle bacillus becomes- 

 distinctly alkaline, and retains this reaction. 



* Centralbl. Bakt., Ref., l te Abt., xxxvi. (1905) p. 654. 



