EFFECTS ON ANIMALS. 435 



witsch; but according to Petri, and Hormann and Morgen- 

 roth, this only occurs if tuberculosis is simultaneously- 

 present. 



When butter is experimented with (4 to 5 c.c. of the 

 previously thoroughly mixed mass, melted at 37° and 

 containing butter-fat, watery part, and casein layers), if 

 the bacilli are present in abundance, a fatal result often 

 follows the injection after three to fifteen days. There 

 are then found changes similar to those described above, 

 only very much more intense, the abdominal organs being 

 covered with well-developed inflammatory, fibrinous mem- 

 branes which are swarming with the organisms. 



Rabinowitsch found rabbits insusceptible in contrast to 

 guinea-pigs. It is generally admitted that guinea-pigs are 

 the most suitable experimental animals, although single 

 reports concerning infection qf rabbits are not lacking. 



Korn could infect only mice with the pure culture of 

 his Friburgensis (0.5 c.c. of a suspension or larger doses). 



Whether injected into the blood-vessels, subdurally, or 

 into the kidneys, the organisms produce more or less 

 well-developed areas, such as described on page 416 in 

 true tuberculosis: i. e., formations resembling actinomy- 

 cosis, but which disappear in the course of months. The 

 animal body destroys the organisms which are introduced 

 (Lubarsch and 0. Schultze). 



Also, in the structure of the accompanying miliary 

 tubercles, these authors can often detect no difference from 

 those of true tuberculosis. 



Little has yet been learned concerning the distribution 

 of the organisms resembling the Mycobac. tuberculosis. 

 However, it appears very wide, for about 60% of butter 

 samples in Berlin contained such organisms, and the in- 

 vestigations of Moeller demonstrated their frequent occur- 

 rence in manure, on grasses, etc. Lubarsch and Dieu- 

 donh6 verified this. 



To obtain the acid-proof bacteria from butter, about 4 

 gm. are injected intraperitoneally in two guinea-pigs with 

 a wide cannula, as indicated above. After about six to ten 

 days the animals, if not dead, are killed, and cultures are 

 prepared from the contents of the abdominal cavity which 

 yield acid-proof bacteria, growing at room temperature. 



