CHAPTER II 

 adaptation in the bacteria 



The Evolution of the Infectious Diseases 1 



It is absurd in these days to imagine that the infections have 

 always been with us : absurd to expand the Batesonian hypo- 

 thesis and imagine that when the woman gave the man the 

 fruit of the tree — or whenever man became man — with that 

 most becoming knowledge of his nakedness he acquired the 

 germs of all bodily ills : that while lues may already have in- 

 fected his ancestors and their relatives the higher apes, the 

 germs of typhoid, cholera, gonorrhoea, and other purely human 

 ailments were already there, only waiting for his appearance 

 to enter into his body, as into a house newly swept and garnished. 



The Antiquity of Zymotic Diseases 



Admittedly some diseases have been with us from the remotest 

 historical times, aye, and we have evidence, from prehistoric 

 times. The earliest Greek medical writings afford us an un- 

 mistakable picture of tuberculosis. If we may accept Bishop 

 Ussher's chronology, the fifth and sixth chapters of the First 

 Book of Samuel show — as I believe I was the first to point out, 

 in the light of our modern knowledge of the natural history of this 

 disease 2 — that the Oriental plague was active over three thousand 

 years ago, presenting the same striking characters as it manifests 

 to-day. At a still earlier historical era, in fact in the earliest 



1 This chapter follows the lines (though with considerable modification) of 

 an address given by me before the Medical Society of the State of Vermont at 

 its annual meeting at Rutland, Vt., in Feb. 1915, and pubb'shed in the 1914 

 volume of the Transactions of that Society. 



2 Montreal Medical Journal, xxiv., 1896, 995. 



15 



