LKCTURE VII.] HISTORY OF CHEMISTRY. 121 



this water also was neglected, as if non-existent, in most of the 

 discussions as to the constitution of bases and acids. It may 

 have been a consequence of this that the presence of water was 

 assumed even in substances which belonged to other classes, 

 when hydrogen and oxygen were found in them in the propor- 

 tions necessary to form water, and that this water was then 

 neglected in writing formulae for these substances. Many things 

 might be adduced as having contributed to erroneous ideas of 

 this kind ; such, for example, as the way in which Gay-Lussac 

 and Thenard in 1811 interpreted their analytical results relat- 

 ing to organic substances. 38 According to these chemists, 

 substances fall naturally into (i) those which contain just as 

 much oxygen as is required in order to form water with the 

 hydrogen present (carbohydrates) ; (2) those which contain less 

 (resins, oils) ; and (3) those which contain more (acids). 



I regarded these perhaps seemingly detailed explanations as 

 necessary, before I could enter more minutely into the views 

 respecting the constitution of organic compounds. In passing 

 on now to this most important question, I wish to show how 

 dualism was gradually introduced here also, and how the radical 

 theory arose as a consequence of this. 



Berzelius explained in 1819 that his electro-chemical theory/ 

 could not be extended to organic chemistry, because under the 

 influence of the vital force the elements there possessed entirely 

 different electro-chemical properties. In decay, putrefaction, 

 fermentation, etc., he observes phenomena which he regards as 

 demonstrating the tendency of the elements to return to their 

 normal condition. 39 He did not, at that time, as yet consider 

 it possible to regard all organic substances as binary groups. 

 Dualism was, indeed, extended as far as possible ; the oxygen 

 compounds were looked upon as " oxides of compound radicals, 

 which, however, do not exist free, but are wholly hypothetical," 40 

 a mode of regarding the matter which was especially applicable 

 to the acids. Accordingly, we now hear the radicals of acetic 



38 Rech. phys. chim. 2, 265. 39 Essaietc., 96. 40 Berzelius, Lehrbuch. 

 First Edition, 3, Part I. 149. 



