322 OUTLOOK FOR THE FUTURE 



a few of which have proved to be of practical value. The chemist has 

 started from a certain lead, such as the arsenical group in the salvarsan 

 type of compounds and the sulfa-radical in the sulfanilamides. The dis- 

 covery of new chemical agents possessing antibacterial or antifungal 

 properties offers the chemist many new models to draw upon for varied 

 types of syntheses. 



Although only very few antibiotics have so far been isolated and 

 their chemical nature determined, it is already well established that we 

 are dealing here with a great variety of chemical compounds. It is suffi- 

 cient to mention, first of all, the penicillins and other sulfur-bearing 

 compounds, such as gliotoxinj the organic bases, notably streptomycin 

 and streptothricinj the polypeptides, especially tyrothricinj the oxida- 

 tion-reduction systems, namely pyocyanin and actinomycin j the ketones 

 and quinones, such as clavacin and many others. Compounds like acti- 

 nomycin, which are highly active against bacteria but also highly toxic 

 to animals, may possibly be modified in such a manner as to reduce their 

 toxicity without impairing their activity. This is also true of simpler 

 compounds, such as the less toxic but also less active clavacin and glio- 

 toxin. The solution of the chemical nature of penicillin offers many 

 tempting opportunities for the synthetic chemist. 



Doubtless most of the compounds that prove to be useful as chemo- 

 therapeutic agents will sooner or later be synthesized. The contribution 

 of the bacteriologist may be all but forgotten in the light of the forth- 

 coming chemical developments, but even the bacteriologist will be 

 grateful for new tools to help combat disease-producing agents. 



THE FIELD OF CHEMOTHERAPY 



The utilization of the activities of antagonistic microorganisms for 

 the control of human and animal diseases has only begun. Many prac- 

 tices in surgery and many old-time remedies are based on the creation 

 of conditions favorable to the development of antagonistic microbes. 

 Plaster treatment of wounds, without the use of antiseptics, has often 

 given marvelous results. Such wounds have been found to contain 

 aerobic bacteria with no one group predominating, except that Ps. aeru- 

 ginosa tends to become more numerous when the healing process has 



