STREPTOCOCCUS INFECTIONS. 523 



quently followed by peritonitis and septicemia. 

 Virulent organisms probably reach the intestines 

 through milk in many instances. Escherich found 

 streptococci in nearly every sample of milk which 

 he examined. Digestive disturbances due to other 

 causes predispose to infection. The organisms are 

 nearly always present in the intestines of the 

 adult, but cause enteritis less frequently than in 

 children. 



The normal vagina does not offer a good cul- 

 ture medium for pathogenic bacteria, although 

 streptococci are occasionally found there. They 

 occur more frequently in those who have borne 

 children. The vagina tends to purify itself me- 

 chanically and by the acid nature of its secretions. 

 If the secretion for any reason becomes alkaline, 

 as in catarrhal conditions, or if it contains blood 

 and serum, which provide a good culture medium, 

 virulent streptococci proliferate. Infection takes 

 place through denuded surfaces and tears ; endome- 

 tritis, metritis, parametritis, salpingitis, peri- 

 tonitis and sepsis ma}'' follow. Thrombosis of the 

 blood vessels may be followed by the development 

 of pneumonic foci. 



Streptococci are probably always present on the upper 



f , ., ,T Respiratory 



tonsils, the mucous membrane of the mouth, very 

 frequently in the sputum and not infrequently on 

 the mucous membrane of the anterior nares. Pre- 

 sumably they proliferate under inflammatory con- 

 ditions from whatever cause, finding in the serum 

 and plasma which exude a medium favorable for 

 growth and the development of virulence. They 

 are of great significance in severe local inflamma- 

 tions, as in diphtheria and scarlatina, and when 



