CHAPTER 14 



THE OUTLOOK FOR THE FUTURE 



The production of antibiotic substances by microorganisms under con- 

 trolled laboratory or factory conditions and the utilization of these sub- 

 stances for disease control are of very recent origin. It has been known 

 for more than half a century that certain microbes are capable of com- 

 bating others, and it has even been suggested that saprophytic micro- 

 organisms may in time be utilized for controlling the growth of patho- 

 genic forms. Until recently, however, these suggestions were largely 

 speculative. Such positive facts as were available were merely isolated 

 items, the full significance of which was not sufficiently well recognized. 

 This is true, for example, of the claims and counterclaims concerning 

 pyocyanase and pyocyanin, two antibiotic substances of bacterial origin, 

 the antibacterial properties of which have long been known. It is true 

 also of certain antibiotic substances produced by fungi, such as gliotoxin. 

 The existing confusion is due largely to the fact that the utilization of 

 these antibiotic substances for disease control gave results that v/ere 

 rather disappointing. 



In 1929, Fleming observed that the growth of a mold, which was 

 later identified as P. notatum, on a plate seeded with staphylococci pre- 

 vented the growth of these bacteria. In liquid media, this mold pro- 

 duced a soluble substance, designated as penicillin, that inhibited pyo- 

 genic cocci and members of the diphtheria group but not gram-negative 

 rods. Fleming, however, did not go beyond the suggestion that this sub- 

 stance be utilized for disease control or beyond the statement that 

 it might prove useful because of these antibacterial properties. This 

 contribution received no further attention for more than a decade, with 

 the exception of very few experiments that served to prove Fleming's 

 original observations. The full realization of the fact that we are dealing 

 here with an entirely new field of biology and chemotherapy that is 

 bound to enrich the subject of control of disease came only about half a 

 decade ago. 



In 1939, Dubos announced that new antibacterial agents can be iso- 



