INFECTION AND INTOXICATION. 71 



usual affections are observed, and the case progresses, 

 other things being equal, toward a fatal termination. If, 

 however, the infection occur into the skin, a local tuber- 

 culous disease, lupus, results, and in its usual course 

 spreads slowly, lasts for many years, and does not tend 

 toward a fatal issue. 



The injection of virulent cholera organisms into a vein 

 or beneath the skin of a guinea-pig is followed by death 

 from cholera-septicemia; but injection into the peritoneal 

 cavity results, not in septicemia, but in choleraic peri- 

 tonitis. 



When streptococci are injected beneath the skin they 

 are apt to produce erysipelatous and suppurative inflam- 

 mations, but when injected into the circulation they pro- 

 duce septicemia. Pneumococci reaching the lung, pre- 

 sumably by the respiratory passages, induce croupous 

 pneumonia; but in the metastatic lesions of pneumonia 

 we find abscess formation the usual outcome of their 

 activity. Among the unusual pneumococcus infections 

 cerebrospinal meningitis and conjunctivitis may be men- 

 tioned. 



The fatality of the microbic diseases depends very 

 largely upon the method of inoculation; thus, Klemperer 

 found that dogs died more readily when pneumococci 

 were injected beneath the skin than when they were 

 injected into a vein. 



These illustrations are sufficient to suggest that certain 

 bacteria are adapted for growth under certain conditions 

 which exist in certain parts of the body, and that their 

 maximum deleterious action is manifested only when 

 they enter the body in such a manner as to be brought^ 

 in contact with them. While not impossible, it therefore 

 becomes improbable that the presence of typhoid bacilli 

 upon the conjunctiva will be followed by successful severe 

 infection, their natural sphere of pathogenesis being in 

 the intestine. The same is true of the presence of the 

 diphtheria bacilli in the intestine, they finding their best 

 sphere of operation in the throat. 



