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CHAPTER II. 

 DOCTRINE OF ACID AND ALKALI. SYLVIUS. 



AMONG the results of mixture observed by 

 chemists, were many instances in which two 

 ingredients, each in itself pungent or destructive, 

 being put together, became mild and inoperative ; 

 each counteracting and neutralizing the activity of 

 the other. The notion of such opposition and neu- 

 trality is applicable to a very wide range of chemical 

 processes. The person who appears first to have 

 steadily seized and generally applied this notion is 

 Francis de la Boe Sylvius; who was born in 1614, 

 and practised medicine at Amsterdam, with a suc- 

 cess and reputation which gave great currency to 

 his opinions on that art 1 . His chemical theories 

 were propounded as subordinate to his medical doc- 

 trines; and from being thus presented under a most 

 important practical aspect, excited far more atten- 

 tion than mere theoretical opinions on the composi- 

 tion of bodies could have done. Sylvius is spoken 

 of by historians of science, as the founder of the 

 iatro-chemical sect among physicians; that is, the 

 sect which considers the disorders in the human 

 frame as the effects of chemical relations of the 



1 Sprengel. Geschichte der Arzneykunde. vol. iv. Thomson's 

 History of Chemistry in the corresponding part is translated 

 from Sprengel. 



