ORGANIC SUBSTANCES. 667 
spring from the reciprocal union of simple elements, and organic 
chemistry must likewise embrace all such substances as are formed 
from compounds possessing the properties of simple elements. 
“In mineral chemistry the radicals are simple, in organic they 
are compound—this is the whole difference. The laws upon 
which combination is based are in both the same. 
“ According to our view, organic chemistry presents us with 
radicals, which play the part of metals, and with others which 
play the part of oxygen, sulphur, chlorine, &c. These radicals 
combine with each other or with simple elements in accordance 
with the most simple laws of inorganic chemistry, and thus give 
rise to all organic compounds.” 
Amongst the details Dumas commits a palpable historical 
error when he affirms, that he and Liebig have been employed 
every day during the last ten years in endeavouring to discover 
and study these radicals. 
Since that period I am not aware that Dumas has made any 
application of these views; Liebig however has retained them, 
and his ‘ Organic Chemistry’ begins with the words, “ Organic 
chemistry is the chemistry of compound radicals.” 
Both these chemists undertook an experiment, each after his 
own manner, and at the same time that the declaration of the 
above views was made, for the purpose of explaining theoreti- 
cally the loss of water which anhydrous double salts of oxide of 
antimony and other bases experience when heated to 200° C.; 
both the explanations however which they have advanced appear 
to prove, that neither of them had given a thought to the 
theorems just mentioned, which both had so warmly advocated. 
Some time before he made the statement concerning organic ra- 
dicals, Dumas began a closer examination of the fact discovered 
by Gay-Lussac, that wax exposed to dry chlorine gas gradually 
converted it into hydrochloric acid gas, without effecting any 
change of volume; from which it follows, that wax parts with 
its hydrogen and absorbs chlorine in such proportions, that both 
in the gaseous form occupy the same volume. Dumas felt the 
great importance which this fact must have upon the doctrine 
of organic composition, and commenced an investigation of the 
laws. He showed at the same time that the greater number of 
organic substances, when they are treated with chlorine or bro- 
mine, exchange hydrogen for the salt radical, gencrally in equi- 
valent proportions of the elements replacing each other. 
