Chemical Constitution of Metacetonic Acid. 267 



ingenious, though often untenable, frequently stumble and 

 fall amongst a host of contradictions. It is a common error, 

 as experience teaches, into which young chemists are very apt 

 to fall, that, persuaded of the infallibility of their own views, 

 and blind to M-ell-founded objections, they endeavour to con- 

 vince by quick and ready argument rather than by solid rea- 

 soning, and consequently they cither offend others or feel 

 themselves offended w-hen contradicted. 



When in the face of this danger we endeavour to advance 

 views concerning the rational composition of some organic 

 acids which do not accord with those generally received, we 

 do it with a certain degree of timidity, and with the most 

 strenuous endeavour to avoid those causes of error which have 

 been pointed out. It is far from our intention to give a de- 

 cided preference to the mode of viewing the subject here pro- 

 posed, or indeed in any way to force our own opinion, nor 

 is it unknown to us that even these views leave many facta 

 unexplained ; but we feel convinced that no detriment can 

 accrue to the progress of science by looking at subjects of 

 Buch importance with an impartial eye from all possible sides. 



The starting-point of our experiments was the idea recently 

 expressed by Berzelius, that acetic acid might be considered 

 as a conjugate oxalic acid, as methyl-oxalic acid, Cg H^ Cg O3. 

 If this view of the subject, which explains so readily the con- 

 version of acetic acid into chloracetic acid, and the remark- 

 able reconversion of the latter into the former, and W'hich has 

 been further confirmed by the analogous relations of chloro- 

 carbohyposulphuric acid and methyl-hyposulphuric acid, is 

 correct, then the question arises whether it might not be ex- 

 tended to those other acids, so nearly related to acetic acid, 

 namely, formic acid, metacetonic acid, butyric acid, benzoic 

 acid, &c. We are of opinion that this question cannot a pri- 

 ori be answered in the negative ; on the contrary, it appeared 

 to us, after pursuing the subject further from that point of 

 view, that the manifold metamorphoses which the above 

 combinations undergo might be explained in a very simple 

 manner, and we consequently have submitted the question to 

 careful experimental examination ; and we believe that we 

 have gained a fact in support of the theory of conjugate com- 

 pounds in its application to the acids in question, by the ac- 

 tion which cyanide of ethyle exhibits with alkalies and acids. 



When benzoic acid is supposed to consist of oxalic acid 

 with the carburetted hydrogen, Cj2 H5 (phenyle), as a con- 

 junct, then it is evident that benzoe-nitrile obtained by Feh- 

 ling* in distilling benzoate of ammonia, must be a cyanogen 

 * Liebig's Annalen, xlix. pi 91. 



