Biography of Berzelius. 21 



far from having advanced so far as to be able to treat of all 

 organic bodies as radicals, oxides, chlorides, &c, as in inor- 

 ganic chemistry. Most of the assumed organic radicals, often 

 of a complicated nature, are of a hypothetical nature ; they 

 gain a somewhat certain character only when some com- 

 pounds of the radical with other simple radicals can be pro- 

 duced, and the oxygen in them replaced by chlorine, sulphur, 

 &c. In addition to this, chemists are of very different opi- 

 nions as to how the composition of organic bodies is to be 

 represented, even when they agree in a fundamental prin- 

 ciple. Moreover, as is natural, the different arrangements 

 vary, according as more new facts are discovered. For the 

 present, therefore, it is at least more advantageous to treat 

 of organic bodies in an elementary work in such a way as 

 Berzelius has done, namely, in groups containing those bodies 

 which have the greatest general similarity in chemical cha- 

 racters. It has frequently been seen, that works in which 

 a^theoretical principle has been strictly followed throughout, 

 do not so well fulfil their principal object. 



In the organic part of his work, Berzelius has declared 

 himself against the so-called substitution theory, and the 

 law of types. He assumes, on the contrary, that conjugate 

 compounds exist in organic bodies, in which, for instance, 

 acids are united with compound radicals, or with their oxides, 

 chlorides, &c, in such a way that the acid is not saturated, 

 but is still capable of combining with bases without separa- 

 tion of the associated substance, — the conjunct, — which enters 

 with the acid as a constituent of the salt. When an acid has 

 entered into such a conjugate combination, it has generally 

 acquired such altered characters, that neither the acid nor its 

 salts are similar to the free acid and its salts. When hydro- 

 gen is replaced in an organic substance by chlorine, or an- 

 other halogen, this generally takes place in the conjunct and 

 not in the acid, and the former does not on this account cease 

 to play its former part, of modifying the character of the 

 salts into which it enters, with its acids, more or less, and 

 accordingly as its composition is altered by substitution. 



It has been asserted that the replacement of hydrogen by 

 chlorine, in organic compounds, was not to be explained 



