PRINCIPLES OF VETERINARY SURGERY 



119 



streptococcus of interest to the veterinary surgeon, is found 

 abundantly in discliarges from mucous membranes, on the 

 skin rather deeply imbedded in the sebaceous dUcts and hair 

 follicles, in the mouth, throat, intestines and bronchial tubes. 

 It is very frequently found in the pus of such well known les- 

 ions as fistula of the withers, poll-evil, infective mastitis and 

 cold abscess of the mastoido-humeralis. In these suppura- 

 tive processes the staphylococcus pyogenes aureus et albus 

 is very frequently associated with it. 



Cultivation. — The pyogenic streptococci can be grown 



Fig. 7. 

 Streptococcus Pyogenes from Culture. 



on gelatin, blood-serum, potato, agar-agar, or in bouillon 



and in milk. It grows at ordinary house temperature, but 



its most rapid growth occurs at the temperature of the body. 



It grows best on blood serum. 



Isolation. — It may be isolated from smear cultures, but 

 the best method is to inoculate a rabbit or mouse and then 

 search for the micro-organism in the blood, in which it can 

 usually be found. 



Staining. — It stains by Gram's method or with the aque- 

 ous anilins. Methylene blue stains it. 



Pathogenicity. — The streptococcus pyogenes has been 

 found in a variety of lesions, varying in gravity from fatal 

 human erysipelas to a simple dermal pustule of a mouse. It 



