56 PA THOGENIC BA CTERIA. 



in a pulverized liquid, infection takes place much less 

 readily. 



Tuberculosis and pneumonia are in all probability 

 generally the result of the inspiration of the specific 

 organisms. 



(c) The Skin and the Superficial Mucous Membranes. 

 The entrance of bacteria into the tissues by way of the 

 skin is probably extremely rare if the skin is sound. 

 Numerous experimenters have caused infection by rub- 

 bing bacteria or their spores upon the skin. It would 

 seem probable that in these cases there must have 

 been some microscopic lesions into which the bacteria 

 were forced. My own investigations have shown viru- 

 lent staphylococci of suppuration upon the conjunct! vse 

 in health. It is very improbable that the bacteria habit- 

 ually present upon the skin, and ready to enter the least 

 abrasion, can penetrate the outer coverings of the body, 

 except when disease or accident has rendered them 

 abnormally thin or macerated. 



Turro seems to have shown that the gonococcus can 

 enter the tissues without any pre-existing lesion, for he 

 asserts that if a virulent culture simply be touched to 

 the meatus urinarius, the disease will be established. 



(d) Wounds. The results of the entrance of bacteria 

 into unprotected wounds are now so familiar that no 

 one deserving of the name of surgeon dares to allow a 

 wound to go undressed. 



(e) The Placenta. Very frequently the occurrence of 

 specific diseases during pregnancy causes abortion of 

 the product of conception. In certain cases the specific 

 contagion passes through the placenta and infects the 

 fetus. This has been pretty clearly demonstrated for 

 variola, malaria, syphilis, measles, anthrax, symptomatic 

 anthrax, glanders, relapsing fever, typhoid, and in rare 

 cases for tuberculosis. 



Seeing that the channels by which bacteria can enter 

 the body are so numerous, and that there is scarce a 

 moment when some part of us is not in contact with 



