130 Proceedings of the Royal Society 
speculation. Meconic acid has always been considered a tribasic 
acid, which, by the successive elimination of two molecules of car- 
bonic anhydride, yields first a dibasic and then a monobasic acid. 
But chemists now know that the basicity of an acid may be less 
than its atomicity, and that even the former cannot be deduced 
from the composition of one or two isolated salts, but only from 
a comprehensive view of all the salts and ethers of the acid. As 
now a general review of the salts and ethers of meconic acid seems 
to point to an acid with an atomicity greater than its basicity, and 
as any additional proof of this constitution would help to explain 
many abnormal decompositions in the series, the authors have in- 
vestigated the action of the general reagents on these compounds 
that enable us to distinguish between the basic and alcoholic 
hydroxyls. In this paper we communicate to the Society some of 
the results obtained in the course of our experiments, as a recent 
paper, by Baron von Crofft, on the action of nascent hydrogen on 
the members of this group, shows that other chemists are working in 
the same direction. The introduction of hydriodic acid and penta- 
chloride of phosphorus as general reagents in organic chemistry 
has been productive of the happiest results, through the easy 
separation of the water residue, HO. By their use we have ob- 
tained a very complete knowledge of the relation of acids, alcohols, 
and hydrocarbons, and we now await the discovery of some reagent 
that will separate the ammonia residues with as great ease, to 
obtain a more precise knowledge of the structure of the organic 
alkaloids. 
When meconic acid is treated with hydriodic acid of constant 
boiling point at 150° C., carbonic anhydride is evolved, and large 
quantities of free iodine liberated. No definite compound could he 
separated from the products of this decomposition. As the first 
action of the hydriodic acid was to form comenic acid, and as many 
actions succeed with concentrated hydriodic acid that are unman- 
ageable with the dilute, we attempted the reduction by the action 
of a saturated solution of hydriodic acid on comenic acid. As 
Berthelot has lately shown that the action of concentrated hydriodic 
acid, at high temperatures, on mono- and bi-basic acids of the fatty 
series, regenerates the hydrocarbon from which they were derived, 
the formation of a hydrocarbon in this reaction was not impossible. 
