BANISHING THE PLAGUES 



has tended to support this idea of the specific char- 

 acter of the toxins that are able to produce dele- 

 terious effects on living tissues. The idea runs 

 counter to the crude general notion that whatever is 

 poisonous to one protoplasmic cell is poisonous to 

 another. But the evidence strongly supports the new 

 theory. Indeed the fact that an antitoxic serum 

 such as Behring's diphtheria antitoxin counteracts 

 the diphtheria toxin and no other, brings the theory 

 of the specific nature of toxins and antitoxins to 

 substantial demonstration. 



Such being the case, and it being tolerably clear 

 that the body is able, under favorable conditions, to 

 produce a specific antidote for each type of bacterial 

 toxin, it seemed to Ehrlich within the possibilities 

 that synthetic chemistry might be able to develop 

 corresponding antidotes in the laboratory test tube. 

 His own early work had shown, as we have seen, that 

 certain dyes of the aniline series have the property 

 of staining cells of one type and leaving cells of an 

 allied type unstained; so it occurred to him that by 

 utilizing this selective affinity of the aniline dye, and 

 combining this agent with a drug that is toxic to 

 protoplasm, he might be able to develop specifics 

 which would search out a particular type of disease 

 germ and destroy it without injuring the tissues of 

 the patient in whose system the disease germ lurked 

 and proliferated. ,; 



The attempt to put this idea in practice involved 

 almost numberless complications. To mention a 

 single one, it was early discovered that tests of the 

 germicide power of any given drug when made in the 



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