Question: why was salvarsan considered to be a magic bullet for the treatment of syphilis

title: Magic bullet (medicine)
text: In 1906 Ehrlich developed a new derivative of arsenic compound , which he code - named Compound 606 ( the number representing the series of all his tested compounds ) . The compound was effective against malaria infection in experimental animals . In 1905 , Fritz Schaudinn and Erich Hoffmann identified a spirochaete bacterium ( Treponema pallidum ) as the causative organism of syphilis . With this new knowledge , Ehrlich tested Compound 606 ( chemically arsphenamine ) on a syphilis - infected rabbit . He did not recognise its effectiveness . Sahachiro Hata went over Ehrlich 's work and found on 31 August 1909 he found that the rabbit , which had been injected with Salvarsan 606 was cured using only a single dose , the rabbit showed no adverse effect . ( The normal treatment procedure of syphilis at the time involved two to four years routine injection with mercury . ) Ehrlich , after receiving this information , performed experiments on human patients with the same success . After convincing clinical trials , the compound number 606 was given a trade name `` Salvarsan '' , a portmanteau for `` saving arsenic '' . Salvarsan was commercially introduced in 1910 , and in 1913 , a less toxic form `` Neosalvarsan '' ( Compound 914 ) was released in the market . These drugs became the principal treatments of syphilis until the arrival of penicillin and other novel antibiotics towards the middle of the 20th century . Ehrlich 's research on the magic bullet was the foundation of pharmaceutical research . 

Answer: answer: Sahachiro Hata went over Ehrlich 's work and found on 31 August 1909 that the rabbit, which had been injected with Salvarsan 606 was cured using only a single dose and showed no adverse effect. Ehrlich, after receiving this information, performed experiments on human patients with the same success.