142 ESSENTIALS OF BACTERIOLOGY. 



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 

 "mal 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 oxygen. 



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 Culture. 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. 



Pathogenesis. If a pure culture is injected into the mammary 

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

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

 oadematous, likewise the thighs and perineum ; the mammae 

 ver}* much enlarged, and at the nipples a blue-violet coloration. 

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

 In rabbits abscesses at the point of infection, but no general 

 affection. 



Bacillus Alvei. (Cheshire and Cheyne.) Bacillus melittopli- 

 tharus. (Cohn.) 



Origin. In foul-brood of bees. 



Form. Slender rods, with round and conical-pointed ends ; 

 very large oval spores, the rod becoming spindle-shaped when 

 they appear. 



Properties. Motile, liquefying gelatine rapidly. 



Growth. Grows best between 20 C. and 37 C., very slowly ; 

 Aerobic. . 



