INTRODUCTORY 



3 



111 tracing the history of antiliiotics, which 

 brought about a revohition in medical sci- 

 ence and cHnical practice, the futiu'e his- 

 torian will no dotibt designate the years 

 1939 to 1940 as a turning point in the history 

 of medicine and of microbiology as well. In 

 those years began a period which has already 

 been designated, medically speaking, as the 

 Age of Antibiotics. The actinomycetes have 

 played a dominant part in this development. 

 With the single exception of penicillin, they 

 ha\'e yielded the most important antibiotics 

 now used in medicine, in \'eterinary science, 

 and in animal nutrition. Annual production 

 of antibiotics, mostly produced by actino- 

 mycetes, has reached the colossal figure of 

 2..") million pounds in the United States 

 alone. 



In addition to streptomycin and neomy- 



cin, the actinomycetes liave contributed 

 chloramphenicol, the tetracyclines, the 

 erythromycins, the novobiocins, and the 

 polyenes, to name only a few. Numerous 

 industrial plants in this country and abi-oad 

 are concerned with the manufacture of anti- 

 biotics produced by actinomycetes. Hun- 

 dreds of laboratories throughout the world 

 are engaged in the search for new antibiotics 

 active upon diseases not subject to control 

 at the present time; in this search, actino- 

 mycetes and their antibiotics play a dom- 

 inant part. 



The story is still far from complete. In 

 presenting this summary, the authors hope 

 to coordinate information that has been 

 accumulating so rapidly that even the ex- 

 perts have had difficulty in absorbing and 

 assimilating it. 



