HISTORY OF MEDICINE. 391 



the theory and practice, and Argenterius criticised the system 

 of Galen very freely, but they had little effect towards promot- 

 ing any general change. Something more violent was necessary 

 to shake an authority which had been so long established. This 

 at length happened ; and a considerable schism was formed in 

 the schools of physic, which very soon gave occasion to a con- 

 siderable difference in the state of practice. 



Sixth Period. It has been already remarked, that chemistry 

 appeared first among the Arabians, and it is probable that some 

 of their first operations were upon metallic substances. Accord- 

 ingly we find a preparation of mercury mentioned in Rhazes ; 

 and the invention of distillation, which gave occasion to distin- 

 guish an art by the name of Chemistry, happened much about 

 the time that the Arabians first appeared in literature, and 

 they are commonly considered as the inventors of this art. Why 

 the name of chemistry was imposed, or how several different 

 practices were associated under this term, we do not certainly 

 know. It is sufficient to our purpose, that an art under that 

 name was employed in various practices which have at all times 

 since distinguished it, that this art appeared first among the 

 Arabians, and was applied by them to the preparation of medi- 

 cines. These practices, and the application of them to medi- 

 cine we have mentioned, were communicated by the Arabians 

 to their disciples in Europe, and spread there with their physic. 

 We find however that the application of chemistry to physic 

 was not considerable, and, probably, from the violence and 

 danger that often attended the operation of chemical medicines, 

 they were little employed by the regular practitioners, that is, 

 by those who were in possession of the schools of physic ; and 

 therefore it is that we hear but little of them in the writings of 

 the physicians of the thirteenth, fourteenth, and fifteenth cen- 

 turies. There is, however, reason to believe that there were 

 then, as at all times since, some more hardy empirical practition- 

 ers, who employed chemical remedies, and who were occupied 

 in cultivating the art of preparing them. For, about the end 

 of the fifteenth century, when there was little or no appearance 

 of chemistry in the schools of physic, a chemical writing was 

 published under the feigned name of Basil Valentine, said to have 

 been composed by different persons, but who are yet unknown. 



