CHEMICAL REMEDIES 297 



A dose of a chemical remedy, itself non-toxic, sometimes 

 kills the mice while destroying their parasites. Ehrlich warns 

 against treating with " 606 " infants suffering from the 

 septicaemic form of congenital syphilis ; he fears an intoxica- 

 tion with substances derived from the suddenly dissolved 

 spirochsetes. 



The paradox that a patient may give a negative Wassermann 

 reaction which after treatment with "606" becomes positive, is to 

 be explained, according to Ehrlich, by the production of anti- 

 bodies as a consequence of a non-curative dose. And it is a 

 local production of endo toxin, under the influence of arsenic 

 or mercury, which produces the sudden revival of cutaneous 

 eruptions in syphilis, known as the phenomenon of Herxheimer. 



These observations on strains resistant to drugs and to sera 

 have thrown light on the question of the virulence of 

 protozoa. Bacteria also acquire resistance to the defensive 

 powers of the higher animals ; the streptococci and the 

 anthrax bacilli clothe themselves with a mucous capsule ; 

 the typhoid bacilli become insensitive to the agglutinins of 

 the patient whom they are infecting j other bacteria secrete 

 agressins\ all .these are manifestations of resistance. This 

 " immunization of microbes " raises the thought that the laws of 

 virulence may be fundamentally the same for both bacteria and 

 protozoa. 



There is nothing to exclude the possibility of a drug-therapy 

 in bacterial infections also, and it is always possible that our 

 vaccines of to-day, and in particular our sera, marvellous 

 discoveries as they are, and originating in the most scientific 

 empiricism, may give place to physico-chemical remedies better 

 defined and more direct. It is from chemistry that we have 

 to expect advances in the healing art. The phrase of Duclaux 

 is very apt in this connection. 



" With Pasteur chemistry invaded the field of medicine 

 probably never to leave it" 



