APPENDIX E. cxxxv 



stage of decay, and cease to be so when putrefaction is 

 advanced so far that sulphuretted hydrogen is evolved; 

 the central part being often poisonous whilst the surface 

 is wholesome/ There seems every reason to believe that 

 in the changes (short of actual putrefaction) which may take 

 place in these substances, a 'peculiar poisonous principle 

 is evolved/ And so in certain cases where an unhealthy 

 process of suppuration occurs, poisonous products may be 

 generated in a wound, whose absorption into the system 

 is capable of bringing about those general symptoms of 

 blood-poisoning which are characteristic of puerperal fever 

 or of pyaemia 1 . 



If we refer now to the diseases which are most frequently 

 endemic or epidemic in nature, we find them presenting very 

 different degrees of contagiousness. The communicability 

 of some of these affections seems to vary in different epi- 

 demics, and also, even during the same epidemic, in different 

 places. Independently of this individual variability, however, 

 the diseases, looked at as a series, present remarkably different 

 degrees of contagiousness. In some this property seems to 

 be absent, whilst in others it presents a most sure and deadly 

 virulence. 



Ordinary intermittent and remittent fevers are, like rheu- 

 matic fever, endemic rather than epidemic, and may, as we 

 know only too well, be developed in almost any individual (and 

 especially in a new comer) when he ventures into a malarious 

 district. All attempts to connect malaria with the presence 



1 Just as contact with particular compounds (e.g. cadaveric poison) 

 seems to favour the production of such poisonous compounds in a wound, 

 so may the presence of carbolic acid tend to hinder those poison-gene- 

 rating changes which are otherwise apt to occur in some wounds. The 

 success which attends the use of carbolic acid may, therefore, be quite 

 independent of its germ-killing powers, or even of its ability to arrest 

 putrefactive processes in general. It has been shown, indeed, to act 

 quite differently with different fermentable fluids. (' Modes of Origin of 

 Lowest Organisms,' 1871, pp. 81-85, and Dr. Dougal's pamphlet, p. 6.) 



