INFECTIONS OF THE DIGESTIVE TRACT 185 



Witte's peptone had been added, it induced pro- 

 nounced diarrhoea in young dogs, sometimes associated 

 with blood. 



STREPTOCOCCAL AND STAPHYLOCOCCAL INFECTIONS 



The biological characters of the streptococcal and 

 staphylococcal forms of bacteria met with in the human 

 intestine in health and in disease have not yet received 

 sufficient attention. There are indications that this sub- 

 ject is likely within a few years to undergo a much- 

 needed development. In the meantime it is impossible 

 to deal with the subject of streptococcal and staphylo- 

 coccal infections in a really satisfactory way. 



The normal intestine (both small and large) usually 

 contains Gram-positive diplococci in moderate numbers. 

 In culture media these may grow freely in chains, the 

 individual organisms undergoing division hi a plane 

 transverse to the line of the chain development. In 

 bouillon cultures streptococcal organisms are more 

 likely to maintain any virulence they may possess than 

 when grown in sugar media. Large quantities of bou- 

 illon cultures of the Gram-positive diplococci of the nor- 

 mal intestine (which may have developed into chains 

 on the bouillon media) may be injected into guinea-pigs 

 either intraperitoneally or subcutaneously without giving 

 rise to any symptoms or lesions. The human intestinal 

 tract under normal conditions is probably most of the 

 time free from pathogenic streptococci and in normal 

 adults such pathogenic bacteria introduced with milk or 



