MIRACLES' OF SCIENCE 



of the drug soon after being synthesized and chris- 

 tened neo-salvarsan. This drug, when injected hypo- 

 dermically into the tissues or into a vein has the 

 extraordinary property of searching out the so-called 

 spirochete that causes syphilis, and killing this germ 

 without injuring the unwilling host in whose blood 

 and tissues it has found lodgment. The drug is there- 

 fore a specific in the most restricted use of that word. 

 It is aimed to destroy a particular germ, and it ac- 

 complishes this purpose in a large percentage of 

 cases at a single dose. 



The discovery of this remarkable specific did not 

 come about by accident. The drug was nicknamed 

 "606" because 605 syntheses of allied drugs had been 

 made unsuccessfully, from the same derivative 

 (atoxyl), compounded of arsenic and a coal tar 

 product. This puts the discovery of salvarsan on 

 an altogether different footing from the empirical 

 discovery made several decades earlier, that drugs 

 extracted from the cinchona plant have specific 

 power against the germs of malaria. In point of fact, 

 the discovery of Ehrlich may be said to have come 

 as the logical sequence of a line of thought and in- 

 vestigation to which almost his entire working life 

 had been devoted. 



The discoverer first became known to pathologists 

 many years ago through his investigation of stains 

 for microscopic tissues. He devised some remark- 

 able compounds through which he was enabled to 

 stain differentially the different types of white blood 

 corpuscles, proving that these curious cells are not all 

 of one family. Elie Metchnikoff had shown that a 



224 



