XU1—On certain Salis and Products of Decomposition of Comenic Acid. By 
Mr Henry How. Communicated by Dr T. ANDERSON. 
(Read 7th April 1851.) 
The study of the organic acids appears scarcely to have advanced of late years 
pari passu with the other branches of organic chemistry. It seems, indeed, as if 
the development of each of the different departments of the science had been, to 
a certain extent, periodical; each engrossing the labours of investigators to the 
temporary exclusion of the others, themselves to be renewed when some new 
experiments should reawaken an interest in them. 
However this may be, the subject of the natural and artificial bases has proved 
so productive of interesting results as to have recently become the chosen and 
almost exclusive field of inquiry, notwithstanding several investigations which 
have thrown much light on one class of organic acids, namely, that represented 
by the general formula C,H, O,. With the exception of this section, the his- 
tory of the organic acids remains very imperfect, and in many cases we have but 
a meagre account of a few of their salts. 
These remarks apply with peculiar force to the polybasic acids; and it was 
with a view to add something to the existing information respecting this import- 
ant class of bodies that I undertook an examination of the acid which forms the 
subject of the present paper. Although this is not among those which have been 
least investigated, many gaps existed in its history which seemed to me worthy of 
being filled up. I first gave my attention to those of its salts, which had hitherto 
remained undescribed or been but imperfectly examined, not from their possessing 
any very marked interest in themselves, but with the idea of obtaining points of 
comparison between acids likely to occur in the course of the proposed investigation. 
My experiments were performed in the laboratory of Dr T. ANDERSON. 
Comenic acid was discovered by Rogsiquet,* who observed that meconic acid 
undergoes a change of properties when boiled with water, carbonic acid being 
evolved, and a product obtained to which he gave the name Parameconic Acid, 

indicative of isomerism with the original substance. Lixnpic,t however, pointed 
out that there was also difference in composition, and proposed the provisional 
name Metameconic Acid for the new substance, whose composition he represented 
by the formula C,, H, O,,, derived from the analysis of the acid itself and of a 
silver salt. In a subsequent paper} he shewed its bibasic nature, and entered 
* Annales de Chimie et de Phys., Tome 51, p. 244, t Ibid., 54, p. 26. 
¢ Annalen der Chemie und Pharmacie, Band 26. 
VOL. XX. PART II. 3P 
