Anfibiof'ic Research 177 



Physiological Significance fo Producing Organisms 



Waksman and his associates have stressed yet another 

 important and neglected area of antibiotic research. What 

 is the physiological significance of the antibiotics to the 

 organisms that produce them. We assume there is but little 

 reason to believe that the antibacterial action of anti- 

 biotics gives a selective advantage to the producing organ- 

 isms in the particular environment in which these organ- 

 isms occur in nature. There is a reasonable possibility that 

 if some of the time and effort now spent in the screening 

 of tens of thousands of mold filtrates for antibiotic ac- 

 tivity were diverted into a study of the metabolic reactions 

 by which these biologically and chemically unique com- 

 pounds are produced, information of practical as well as 

 academic interest might accrue. 



Chemofherapeufic and Microbiological Horizons 



I am afraid this presentation has emphasized some nega- 

 tive aspects of antibiotic research, rather than its striking 

 positive accomplishments. F'or the physician and for the 

 drug house, the horizon with respect to antibiotics is de- 

 scribed in terms of new agents, with an even broader spec- 

 trum of activity and an even lower order of toxicity; in 

 other words, in terms of prospective cures for diseases not 

 now susceptible to treatment. Large resources of personnel, 

 facilities, and funds are now dedicated to that end, and 

 usually involve the mass screening of mold filtrates. Over 

 the last ten years, that empiric approach has been enor- 

 mously rewarding. But what to do when the rich treasure 

 lode of the Streptomyces has been exhausted? At least with 

 respect to antibacterial agents, that prospect is already 

 upon us. When a new mold is now found to produce a 

 nontoxic antibiotic, that antibiotic almost invariably 



