In continuation of a short paper on meconic acid previously communicated to the Society, I submit the following notice of some of the salts of comenic acid.

As is well known, comenic acid is formed from meconic acid by elimination of carbonic anhydride, according to the equation -C7H4O7=C6H4O5+CO2. This change may be effected by heat alone, but a better product is obtained by the action of boiling aqueous hydrochloric acid. It was by the latter method that the acid used in my experiments was prepared. Comenic acid is easily purified by crystallisation from boiling water, in which it is sparingly soluble, and by conversion into ammonium salt, which is likewise purified by recrystallisation. Comenate of ammonia forms long well-defined prisms, which are much less soluble in water than the corresponding salt of meconic acid.