The specificity of the action of certain drugs against particular infections has been recognized for a great many years. Perhaps one of the first drugs to be so used was quinin, which was employed in its original state in the treatment of malaria, between the years 1630 and 1640. In 1638, it is said to have proved efficacious in the case of the Countess of Chinchon, whose name was later applied to the bark which the Spanish brought from South America.
After an exhaustive investigation of certain arsenic compounds, Ehrlich1 arrived at the formula of arsphenamin in the treatment of syphilis. In this case, the toxophore radical of arsphenamin has a greater affinity for the parasite than it has for the body cells of the animal host.
These two classical cases may be cited as opening the way to further knowledge of specific chemotherapy.
CHEMISTRY OF DYESTUFFS