138 ESSENTIALS OF 13 ACf ERIOLOG Y . 



Bacilli are found in the blood and all the viscera. 



One attack, if withstood, protects against succeeding ones. 



Immunity. Has also been attained by injecting vaccines of 

 t\vo separate strengths. 



Bacillus Murisepticus. (Koch.) Mouse septicaemia. 



Origin. Found in the body of a mouse which had died from 

 injection of putrid blood, and described by Koch in 1878. 



Form. Differs in no particular from the bacillus of swine 

 erysipelas, excepting that it is a very little shorter, making it 

 the smallest known bacillus. Spores have been found, the cul- 

 tures exactly similar to those of swine erysipelas. 



The pathological actions are also similar. Field mice are 

 immune ; whereas for house and white mice the bacillus is fatal 

 in two to three days. 



Micrococcus of Mai de Pis. (Nocard.) Gangrenous mastitis 

 of sheep. 



Origin. In the milk and serum of a sheep sick with the 

 "mat depis." 



Form. Very small cocci seldom in chains. 



Properties, immotile ; liquefying gelatine. 



Growth. Growth occurs best between 20 and 37 C., is very 

 rapid, and irrespective of ox}'gen. 



Plates of Gelatine. White round colonies, some on the surface 

 and some in the deeper strata, with low power, appearing brown 

 surrounded by a transparent areola. 



Stab Cwture. Very profuse along the needle-track, in the 

 form of a cone after two days, the colonies having gathered at 

 the apex. 



Potato. A dirty gray, not very abundant, layer somewhat 

 viscid. 



Staining, with ordinary methods ; also Gram's method. 



PatJwgenesis. If a pure culture is injected into the mammary 

 gland of sheep, a " mat de pis" is produced which causes the 

 death of the animal in 24 to 48 hours. The breast is found 

 oedematous, likewise the thighs and perineum ; the mammae 

 very much enlarged, and at the nipples a blue-violet coloration. 

 The spleen is small and black ; other animals are less susceptible. 



