and its Alkaloid Conia. 385 
observed by Grsrxe, that, on distilling hemlock with water and 
caustic lime, an alkaline liquid of a strong and peculiar odour 
was obtained ; from which, when neutralized by sulphuric acid 
anid concentrated by evaporation, he separated with alcohol a 
substance of the nature of an extract, possessing the poison- 
ous qualities of hemlock in a very eminent degree. Two grains 
of it killed a rabbit in less than an hour. But Gisexke was un- 
able to detach either an alkaloidal or a crystalline principle. 
Proceeding in the same line of investigation, but with more 
precision, Grrcer first found that the distilled water of hemlock 
leaves, or of the green seéds, although it gives out very strongly 
the peculiar mousy odour of the plant, is scarcely if at all poison- 
ous ;—a remarkable fact, when we consider that this odour or 
aroma is usually thought to be a correct measure of the relative 
activity of different specimens, and to possess a narcotic or stu- 
pifying tendency on those exposed to it. The imagination 
has probably had much to do in the formation of these no- 
tions. At all events, we now know that the singular aroma of 
hemlock is owing, like other vegetable odours, to a volatile oil ; 
and that this oil is very feebly if at all deleterious. 
But if the green seeds or leaves, either after or before the 
separation of the volatile oil, be distilled with water and caustic 
potass or lime,—the heat being applied through means of a mu- 
riate of lime bath, to prevent charring,—it will be found that 
the liquid which passes over is strongly alkalineand highly poi- 
sonous ; and I have also commonly observed, where ten or twelve 
pounds of seeds were worked in one operation, that an oily-like 
matter comes over with the first few ounces of liquid, which is 
soluble in acids, insoluble in’ alkalis, strongly alkaline in its ac- 
tion on turmeric, and of a powerful, peculiar, suffocating odour, 
allied to, yet by no means identical with, that of the fresh herb. 
This, in fact, is a small quantity of tolerably pure conia. 
But the greater part of the alkaloid remains in solution in 
the water which is distilled over. If this distilled water be dis- 
