86 INFLAMMATION, SUPPURATION, ETC. 



London, the evidence was concerned practically 

 with physiology alone : very little was said about 

 pathology, and of bacteriology hardly a word. The 

 witnesses say that they " believe they are beginning 

 to get an idea " of the true nature of tubercle : and 

 the evidence as to the nature of anthrax, given by 

 Sir John Simon, reads now like a very old 

 prophecy : — 



" We are going through a progressive work that 

 has many stages, and are now getting more precise 

 knowledge of the contagium. By these experiments 

 on sheep it has been made quite clear that the con- 

 tagium of sheep-pox is something of which the habits 

 can be studied, as the habits of a fern or a moss can 

 be shidied : and zve look forward to opportunities 

 of thus studying the contagium otitside the body ivhich 

 it infects. This is not a thing to be done in a day, 

 or perhaps in ten years, but must extend over a long 

 period of time. Dr Klein's present paper represents 

 one very important stage of a vast special study. 

 He gives the identification of the contagium as 

 something which he has shidied to the end in the 

 infected body, and which can now in a future stage 

 be shidied outside the body." 



Thirty years ago, there was no bacteriology, in 

 the present sense of the word : and now the 

 "habits" of these "contagia" have been studied, 

 outside and inside the body, with amazing accuracy. 

 It has been proved, past all possibility of doubt, 

 that the pathogenic bacteria are the cause of infec- 

 tive diseases ; they have fulfilled Koch's postulates 

 — that they should be found in the diseased tissues, 



