112 BACTERIOLOGY 



perature, but to a higher degree of heat, although, indeed, 

 the growth is more luxuriant, there is not so fine a forma- 

 tion of colour as at the former temperature. This is true 

 particularly of surface cultures on agar, in which a thick 

 column forms at first along the streak, and then gradually 

 spreads out further so as to cover the surface of the agar 

 with a complete coating of culture displaying the charac- 

 teristic colour. On potatoes there occurs a deposit which is 

 at first whitish but afterwards takes on a yellow or orange hue. 



Staphylococci also grow excellently on serum and the 

 white of plovers' or pigeons' eggs. All cultures of them 

 very soon develop a strong smell of paste, which, as the 

 age of the cultures advances, is modified to an odour re- 

 sembling that of sour milk. 



Successful infections have repeatedly been made with 

 staphylococci. When brought upon the surface of wounds, 

 they set up a progressive suppuration, while subcutaneous 

 injections originate abscesses, and injections into the circu- 

 lation cause inflammation of joints and abscesses in the 

 kidneys and myocardium. According to Orth, Wyssoko- 

 witsch and Eibbert, they set up an ulcer ative endocarditis 

 on diseased or perforated cardiac valves. All these phe- 

 nomena are dependent either on the occurrence of a 

 mechanical derangement of the vascular areas by the 

 micro-organisms, or on the development of metabolic pro- 

 ducts having a toxic action on the tissues. In addition to 

 entering by wounds, the staphylococci can find their way 

 into the cutaneous and subcutaneous tissue from the hair 

 follicles and the ducts of the cutaneous glands. 



The Staphylococcus pyogenes albus is distinguished from 

 the last only by the absence of pigment ; it appears to be 

 less energetic in its action. Staphylococcus pyogenes citreus 

 differs also in colour, and liquefies gelatine more slowly than 

 either of the other two. 



