BACTERIOLOGICAL EXAMINATION OF MATERIAL 223 



entrance of bacteria into the portal circulation from the intestines. 

 These are very largely disposed of in the liver, but it may well be 

 that the liver does not always eliminate all the bacteria from the 

 portal circulation, and that some of these then lodge in other tissues 

 and become latent there. 



The latency of bacteria in the healthy body can no longer be 

 questioned. We have long known that treponema pallidum the 

 spirochsetes that infect mice, and many trypanisomes can remain 

 present for a long time in the circulation and in the tissues of animals 

 and man without giving rise to characteristic symptoms or even 

 to any symptoms. We have, ourselves, found pallida in the testes 

 of rabbits four months after inoculation without there having been 

 the slightest tissue reaction, and in human syphilis this latency is 

 well recognized. That tetanus spores may remain latent in the 

 spleen and other organs of guinea pigs under certain experimental 

 conditions, has been shown by the Italian observer, Canfora, 13 and 

 recently we have seen a very convincing example of latency of 

 streptococci in the tissues of the hand. A very severe hemolytic 

 streptococcus lesion subsided under surgical treatment, and four 

 months later a purely cosmetic secondary operation was undertaken 

 at a time when there was not the slightest trace of infection, and 

 hemolytic streptococci were again isolated from the tissues at this 

 operation. There was, incidentally, no sign of infection of the 

 wound, which healed uneventfully. 



The investigations of Torrey and others have shown that from 

 lymph nodes, the seat of various non-bacterial conditions, such as 

 sarcoma, Hodgkin's disease, etc., many varieties of diphtheroids may 

 be isolated, and Roscnau has reported a number of blood culture 

 results in which diphtheroids and cocci were isolated from the blood 

 in the presence of febrile conditions which obviously were not due 

 to the particular organisms isolated. 



Not much can be said about this problem of latency at the present 

 time because little is known about it, but the possibility should be 

 kept in mind, and should cause great conservatism whenever isola- 

 tions from the tissues are made, and the etiological question is raised. 



The Bacteriology of the Intestinal Tract. More than any other 

 part of the body, the intestinal canal has a specific flora of its own. 

 This varies at different ages, with health and disease, and is to 



"Can-fora, Cent. f. Bakt., 45, 1908. 



