ANILINE DYES — LEIKIND 443 



Shortly thereafter two French workers, Mesnil and Nicolle, made 

 up two additional dyes of the same series, trypan blue and afridol 

 violet. The trypan blue was found to be effective against a try- 

 panosome disease of cattle. But the carcasses of cows so treated en- 

 countered sales resistance in the butcher shop. Bright blue meat 

 did not attract customers. A search was therefore started for a 

 colorless trypanocide. The Bayer Company, after synthesizing and 

 testing several thousand compounds, finally developed Bayer 205 or 

 Germanin, which was found to be very effective against African 

 sleeping sickness — so effective, in fact, that the Germans, after World 

 War I, offered to release the formula only in return for their last 

 African colonial empire. Britain refused and shortly thereafter 

 Fourneau of the Pasteur Institute in Paris successfully synthesized 

 the drug. 



Ehrlich meanwhile pressed forward with his own researches. In 

 1906 he was made the head of a privately endowed laboratory in Frank- 

 furt, the George Speyer Haus, devoted exclusively to chemotherapeutic 

 research. As early as 1902 Ehrlich had begun to study certain ar- 

 senic-containing compounds related to atoxyl. This was the first 

 organic arsenical tried in trypanosomiasis. It was named atoxyl be- 

 cause at first it was thought to be nontoxic to the host. This proved 

 not to be so. Ehrlich and his chemists attempted to modify the mole- 

 cule so as to enhance its effect on the parasite while decreasing the 

 toxicity for the host. One byproduct of this work was the production 

 of acriflavin. This chemical, while not effective against trypanosomes, 

 was found to have value as a wound disinfectant. In 1905 Schaudinn 

 and Hoffmann discovered the cause of syphilis and at once Ehrlich 

 began a hunt for a compound effective against the spirochete. Once 

 again he tried modifications of arsenic compounds in the form of a 

 radical hooked onto a dye molecule. In 1909, after testing com- 

 pound 606 in his series, he, together with his assistant Hata of Japan, 

 announced the discovery of salvarsan or arsphenamine as a cure for 

 syphilis. It was Ehrlich's greatest triumph. Among many honors 

 showered upon him was the Nobel Prize. 



Ehrlich now became interested in the possibility of finding a cure for 

 cancer. It was his last major investigation before he died in 1915. 

 That he failed is not to his discredit since no one else has yet dis- 

 covered a cure for this disorder. Yet if and when such a cure is found 

 one may predict that it will probably be discovered along the road 

 and by the methods so successfully charted by Paul Ehrlich. 



The high hopes raised by Ehrlich's brilliant chemotherapeutic suc- 

 cesses were not sustained after his death. For, while a number of 

 compounds had been found which were useful in the treatment of 

 protozoal and spirochetal diseases, no really effective magic bullets 

 had been found against bacterial infections. 



