244 
Selected Articles. 
plant with potash, this liquid having been saturated with vine- 
gar of a less strength. This extract afforded ammonia with 
great facility. 
The extracts of conium, treated with hydrochloric and 
acetic acids, aided by heat, and potash afterwards added, 
gave out an odour of ammonia and cantharides; this disap- 
peared on the addition of an acid, but was restored by satu- 
rating this acid with alkali. 
To determine the source of the ammonia, five grammes of 
of the extract of conium were placed in a capsule with an 
alcoholic solution of potash, and heated for an hour in an oil 
bath, adding distilled water from time to time. To this liquid, 
acetic acid in excess was added; this produced a brisk effer- 
vescence. The filtered fluid precipitated nitrate of lead. The 
precipitate washed and dried, was partly crystalline. De^ 
composed by hydro-sulphuric acid, after filtration and evapo- 
ration a small quantity of crystals were obtained, some of 
which were flat, and the others in prismatic needles. These 
crystals, treated with alcohol at 35° B. gave on evaporation, 
by a gentle heat, very acid, acicular crystals. Calcined on 
a leaf of platina they gave an odour of tartaric acid, and left 
a residuum which reddened turmeric paper. These facts 
suffice, in my opinion, to characterize malic acid; this acid 
has been discovered in conium by Schrader, and M. Bracon- 
not has ascertained that alcohol, in contact with unpurified 
malic acid, will dissolve malate of lime. 
Eight grammes of the same extract were treated in a re- 
tort, furnished with a long tube, the extremity of which was 
plunged into mercury, to get rid of the carbonic acid, and 
the above process repeated with the same results. 
M. Guersent states {Diet, des Sci. Med. art. Cicuta,) that a 
physician of Edinburgh was of opinion, that an extract pre- 
pared with seeds, was more efficacious than that made from 
the plant, but that experience has not verified this idea. 
We may conclude from the above: 
1st. That extracts of conium, more than six weeks after they 
have been prepared, and even the dried plant, when exposed 
