232 CHANNELS OF INFECTION. 



into the circulation were not found in the urine, and when a consid- 

 erable quantity of a pathogenic species was injected into a vein there 

 was no immediate appearance of bacteria in the urine, but they were 

 found later, probably as a result of lesions in the secreting organ due 

 to their local action or to that of their toxic products. In man the 

 presence of pathogenic bacteria in the urine has been frequently veri- 

 fied, especially in typhoid fever, pneumonia, and streptococcus in- 

 fection. When, as a result of the establishment of foci of infection 

 in the liver, localized necrosis of tissue occurs, the pathogenic bac- 

 teria to which the infection is due escape with the bile and enter 

 the intestine. It is probable that escape through the walls of the 

 intestine does not occur unless there is a local lesion of some kind, as 

 in typhoid fever. 



The presence of tubercle bacilli in the milk of cows has been 

 repeatedly demonstrated, and in a certain proportion of the cases 

 they have been found in the milk of cows whose udders gave 

 no evidence of being the seat of a tubercular process. Usually, how- 

 ever, when tubercle bacilli are found in the milk the cow's udder 

 is already involved in the disease. The milk of women with puer- 

 peral fever has been found to contain streptococci ; and in mastitis 

 from a localized infection by pyogenic cocci these are found in the 

 milk. It must be remembered, however, that both Staphylococcus 

 albus and aureus have been found in the milk of healthy women. 

 The micrococcus of pneumonia has been found in the milk of women 

 suffering from croupous pneumonia (Foa, and Bordoni-Uffreduzzi) . 

 Various observers (Brunner, Tizzoni, von Eiselsberg) have reported 

 the presence of pus cocci in the sweat of patients suffering from sep- 

 ticaemia, and the experiments of Brunner indicate that they may have 

 escaped through the sweat glands. This, however, does not appear 

 to be definitely established. 



