ORGANIC BODIES CONTAINING METALS. 
439 
sarily be extended to cacodyl. The discovery and isolation of this so-called organic 
radical by Bunsen was certainly one of the most important steps in the development 
of organic chemistry, and one, the influence of which upon our theoretical views of 
the constitution of certain classes of organic compounds, can scarcely be too highly 
estimated. It was impossible to consider the striking features in the behaviour of 
this body, without finding in them a most remarkable confirmation of the theory of 
organic radicals, as propounded by Berzelius and Liebig. 
The formation of cacodyl, its habits, and the products of its decomposition, have 
for some time left no doubt of the existence of methyl ready formed in this body ; and 
Kolbe*, in developing his views on the so-called conjugate compounds, has proposed 
to regard it as arsenic conjugated with two atoms of methyl ((CgHgjgAs). So long 
as cacodyl was an isolated example of an organo-metallic body, this view of its 
rational composition, harmonizing as it did so well with the facts elicited during the 
route of cacodyl through its various combinations and decompositions, could scarcely 
be contested ; but now, since we have become acquainted with the properties and 
reactions of a considerable number of analogous bodies, circumstances arise, which I 
consider militate greatly against this view, if they do not render it absolutely 
untenable. According to the theory of conjugate radicals just alluded to, cacodyl 
and its congeners, so far as they are at present known, would be thus represented : — 
Cacodyl (Cg H3)2As. 
Oxide of cacodyl (Cg H3)2AsO. 
Cacodylic acid (C2 H3)2As03. 
Stanmethylium (€2113)80. 
Stanethylium (C4 FIgjSn. 
Oxide of stanethylium (C4 HgjSnO. 
Stanarnylium (C^o H^jjSn, 
Zincmetliylium (C2Fl3)Zii. 
Zincethylium (C4H5)Zn. 
Zincamylium (Cjq ^In)Zn. 
Stibethine (Stibethyl) (C4 FIgjgSb. 
Binoxide of stibethine (C4 FIgjgSb O2. 
Oxide of stibmethylium (€3 Ii3)4Sb O. 
Hydrargyromethylium (C2Fl3)Hg. 
Iodide of hydrargyromethylium . , (C2H3)ITgI. 
It is generally admitted, that when a body becomes conjugated, its essential 
chemical character is not altered by the presence of the conjunct: thus for instance, 
the series of acids C„H„04, formed by the conjunction of the radicals C„H(n+i) with 
oxalic acid, have the same neutralizing power as the original oxalic acid; and, 
therefore, if we assume the organo-metallic bodies above mentioned to be metals 
MDCCCLII. 
* Journal of the Chemical Society, vol. iii. p. 372. 
3 L 
