CHAPTER XIV 

 CHEMOTHERAPY 



IN the foregoing chapters we have seen that the animal body 

 has at its disposal a mechanism by means of which it is not only 

 capable in many instances of preventing infection, but even of over- 

 coming this successfully if by any chance microorganisms have 

 once passed the outer barriers and have gained a foothold in the 

 tissues proper. We have also seen that it is possible to introduce 

 some of those substances which the body makes use of in its defence, 

 from without, and that we can frequently turn the balance of the 

 scales toward recovery in this manner, where unaided this would 

 have been impossible, or attended by grave danger. Nevertheless 

 we must admit that only too often all our efforts to combat infection 

 by the body's own methods are in vain, and that in the majority of 

 infections we are still far from a successful treatment. 



In view of the fact that in the test-tube we are able to destroy 

 microorganisms with the greatest ease, by the aid of a large number 

 of chemical preparations, the thought has naturally suggested itself 

 whether it would not be possible to assist the normal defences of 

 the body by the administration of some of these substances. We 

 know as a matter of fact that the only specific medicinal treatment 

 of the older Pharmacopcea, viz., that of malaria by means of quinine, 

 and of syphilis by means of mercury, depends upon the destructive 

 effect of the remedies in question upon the respective parasites. 

 The recognition of this fact is of recent date, however, and does 

 not form the basis upon which the treatment of these diseases was 

 established. The discovery of the therapeutic properties of quinine 

 and mercury, in other words, was not the outcome of logical thought 

 and corresponding experimentation, but purely accidental. 



But the fact that it is actually possible to destroy some of the 

 pathogenic microorganisms in the body of an infected individual by 

 chemical means, would suggest that a similarly fortunate result 

 might be achieved with other substances in the case of other organ- 



