METHOD OF STUDY. 433 



measure but that of imitating, as well as they can, the fashion 

 established by others. It is not, therefore, that by different 

 theories men come at the same practical conclusions, but it 

 is because they either have the same theory or none at all. I 

 know, however, also from much acquaintance with physicians, 

 that though indolence, modesty, or good nature may produce a 

 harmony in consultation, yet every man who has a peculiar 

 theory, will also have a peculiar practice whenever he acts by 

 himself. 



With regard to physicians of different ages, nothing appears 

 to me more false than the supposition of their agreement in prac- 

 tice. The superstitious admirers of antiquity can find in Hip- 

 pocrates every piece of theory or practice that has been started 

 since ; but the slightest acquaintance with the history of physic 

 must inform us how much different ages and sects have differed 

 from each other. Observe only since the beginning of the six- 

 teenth century, how much the Galenists, the Chemists, the 

 Cartesians, the Mechanicians, and the Stahlians, have differed 

 in practice from each other, and all of them, in many particu- 

 lars, from the Ancients. There are, indeed, diseases of frequent 

 occurrence and very similar appearance in all ages, and it is to 

 be supposed, that with regard to these, time and experience have 

 established some general rules of practice, which no new system 

 will venture to contradict; but with regard to the application of 

 these rules, and with regard to practice in diseases of less uni- 

 form appearance, we shall constantly find that, according to the 

 difference of theory, the practice is widely different and even 

 directly opposite. I wish, indeed, it could be said for the 

 theory of physic, that it is harmless, because it absolutely rests 

 on speculation ; but indeed while I plead for it so much, I cannot 

 do it on this ground, and I must own that it has often done harm ; 

 and we cannot think of the physician that Lieutaud mentions 

 who bled his patient one hundred times in a year, and thereby 

 occasioned his death, without horror ; nor can we think, 

 without smiling, of the death of Van Helmont, who, from 

 theory, refused to be blooded in a pleurisy, and endeav- 

 oured to cure it with a little sanguis hirci ; nor can we think 

 of many other such instances without being convinced of the 

 baneful influence of false theory. But I spend your time 



