TYPHUS MURIUM. 345 



gelatin punctures there is no liquefaction. The growth 

 takes place upon the surface principally, where a grayish- 

 white mass slowly forms. 



Upon agar-agar a grayish-white development devoid 

 of peculiarities occurs. 



Upon potato a rather thin whitish growth may be 

 observed after a few days. 



The bacillus grows well in milk, with the production 

 of an acid reaction, but without coagulation. 



The organism is pathogenic for mice of all kinds, 

 which succumb in from one to two days when inoculated 

 subcutaneously, and in eight to ten or twelve days when 

 'fed upon material containing the bacillus. The bacilli 

 multiply rapidly in the blood- and lymph-channels, and 

 cause death from a general septicemia. 



Loffler expressed the opinion that this bacillus might 

 be of use in ridding infested premises of mice, and the 

 results of its use for this purpose have been highly satis- 

 factory. He has succeeded in ridding a field so infested 

 as to be useless for agricultural purposes by saturating 

 some bread with bouillon cultures of the bacillus and 

 distributing it near the holes inhabited by the mice. 

 The bacilli that were eaten by the mice not only killed 

 them, but also infected others which ate the dead bodies 

 of the first victims, and so the extermination progressed 

 until scarcely a mouse remained in the field. The bacilli 

 are not pathogenic for the animals, such as the fox, weasel, 

 ferret, etc., that feed upon the mice, do not affect man in 

 any way, and so seem to occupy a useful place in agri- 

 culture by destroying the little but almost invincible 

 enemies of the grain. 



