226 NATURE OF ANTIBIOTIC ACTION 



The theory of inner antagonism has been suggested (509). The bac- 

 terial cell is said to contain two antagonistic groups, namely coagulants 

 and lysinsj when the correlation between these two groups is disturbed 

 the result is either agglutination and precipitation by the first or lysis 

 by the second. The phage is given as an example of a free inner antago- 

 nist, the lysinj reproduction of the phage is thus explained by the 

 lik^ formation of lysins in multiplying cells. The action of antibiotic sub- 

 stances and resulting cell lysis were also explained by the inner antago- 

 nism. 



It has been postulated (170) that the action of growth-inhibiting 

 substances may consist in prolongation of the lag phase, reduction of the 

 growth rate, lowering of stationary population, or hastening the death 

 of the bacteria. A bactericide has all these effects, whereas a bacterio- 

 static agent may affect one stage selectively. When organisms are al- 

 lowed to grow in the presence of an antibacterial agent, a greater con- 

 centration of the latter is required to bring about a given effect upon the 

 bacterial culture. 



On the other hand, bacteria subjected to the action of an antibiotic 

 substance may develop mechanisms that render them resistant to the 

 action of the substance, and some bacteria and fungi even may produce 

 an enzyme, such as penicillinase, that brings about the destruction of the 

 antibiotic substance. 



The antibacterial action of gramicidin was found (412) to be in- 

 hibited by a cationic detergent, phemerol, whereas penicillin was not 

 affected by either gramicidin or two cationic detergents, phemerol and 

 zephiran. When gramicidin and penicillin were used together, their 

 effect was only slightly additive (394) j however, penicillin and strepto- 

 thricin exerted a marked additive effect upon bacteria sensitive to both 

 of these substances (287). 



The inhibition of the antibacterial action of sulfanilamide by 

 /)-amino-benzoic acid has been explained by the fact that the latter is a 

 growth factor in bacterial nutrition. Competition for this growth factor 

 between the bacterial cell and the bacteriostatic agent is responsible for 

 the inhibition of the agent. In a similar manner pantoyltaurine, which 

 is related to pantothenic acid as sulfanilamide is to /)-amino-benzoic 

 acid, will inhibit the growth of hemolytic streptococci, pneumococci, 



