Antibiotic Research 169 



tical goal remains its chief inspiration and justification. 

 From the point of view of the microbiologist, however, 

 there is a disheartening disparity between the magnitude of 

 this developmental program in the antibiotics and what is 

 known or even attempted with respect to the elucidation 

 of their mode of action. 



Practical Applications of Antibiotics 



Let us first look into the present status of the antibiotics 

 at the practical level. Their impact in clinical medicine re- 

 quires no elaboration. Within a decade, a wide variety of 

 infectious diseases have become amenable to treatment, 

 where previously treatment was ineffective or unsatisfac- 

 tory. Bacterial endocarditis is no longer a hopeless disease; 

 most rickettsial infections can be rapidly cured with the 

 tetracyclines or with chloramphenicol; the clinical manage- 

 ment and prognosis of tuberculosis have been radically al- 

 tered by the advent of streptomycin; and Ehrlich's dream 

 of a single massive sterilizing dose of a nontoxic compound 

 has been finally achieved in the one-injection treatment of 

 syphilis and other treponematoses with penicillin. Early 

 syphilis is, in fact, rapidly disappearing, to the degree that 

 in many urban areas it is becoming difficult to find case 

 material for student teaching; and yaws, one of the major 

 plagues of mankind, has proved similarly susceptible to 

 treatment with a single injection of penicillin. Paren- 

 thetically, I am convinced that the spectacular decline in 

 the attack rate of syphilis is due only in part to the specific 

 treatment of the disease, and in part reflects the haphazard 

 and wholesale use of the antibiotics. Quite unintentionally, 

 this has served to reduce the total reservoir of infection, 

 a desirable by-product of a generally undesirable prac- 

 tice. 



Altogether aside from the clinical importance of the 

 antibiotics, their growth-accelerating effects in young ani- 



