and its Alkaloid Conia. 385 



observed by Giseke, 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 

 and 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 Giseke was un- 

 able to detach either an alkaloidal or a crystalline principle. 



Proceeding in the same line of investigation, but with more 

 precision, Geiger first found that the distilled water of hemlock 

 leaves, or of the green seeds, 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 alkaline and 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- 



