ASThSEPTICS 119 



An outstanding feature of the antiseptic reaction is its 

 immediate effect. As soon as the cells are in contact with 

 the antiseptic, they cease to multiply. The reaction may 

 be compared to pulling the switch of an electric motor. 

 The motor stops and continues to be motionless as long 

 as the current is interrupted, although the motor is 

 intact. It runs again when the switch is thrown in, just 

 as the cells begin to multiply again when the antiseptic 

 is removed. 



This immeasurably rapid reaction of the antiseptic is 

 different from the slow death-producing reaction char- 

 acteristic of a disinfectant. To continue our simile of the 

 electric motor, the disinfectant action is comparable to 

 a gradual deterioration of the motor, as through rust or 

 corrosion by acid vapors. This deterioration also inter- 

 feres with the running of the motor, and it is irreversible, 

 but deterioration is slower than pulling a switch. 



The slow reaction of the disinfectant requires a con- 

 siderably higher concentration of the toxic substance 

 than the instantaneous but reversible reaction produced 

 by the antiseptic, and, in fact, all disinfectants act also 

 as antiseptics at low concentrations. They inhibit mul- 

 tiplication at once, but produce their irreversible effect 

 only gradually. They first, so to speak, pull the switch 

 of the motor, and then cause it to deteriorate. The an- 

 tiseptic only pulls the switch. If there is also deteriora- 

 tion, it is very slow. 



The essential differences between the antiseptic and 

 the disinfectant reactions are thus that one is slow and 

 gradually progressing, but requires a fairly high concen- 

 tration of the toxic agent, and produces an irreversible 

 effect while the other is practically instantaneous and re- 

 quires a relatively dilute solution, but its effect is re- 

 versible. These reactions probably affect different cell 

 constituents, or at least different parts of the molecule 

 (^f the same constituent. A good example of the two re- 



