and its Alkaloid Conia. 389 



bath till the residue had the consistence of syrup, and subjecting 

 this extract, in a proper distilling apparatus, with its own weight 

 of water and a little caustic potassa, to the heat of a concentrated 

 boiling solution of muriate of lime. The conia passes over readily 

 with the water, floating on its surface and quite colourless. 



In the proximate analysis of organic substances, it is of primary 

 consequence that the agents employed be such as will accomplish 

 simple separation of the proximate principles from each other, 

 without producing new compounds by a new arrangement of ele- 

 ments. Some chemists have entertained doubts whether even 

 any of the methods of analysis at present in use fulfil correctly 

 this condition. But all are agreed in thinking that the agency 

 of strong acids or strong alkaline solutions, more especially when 

 concurring with an elevated temperature, should in general be 

 avoided, as tending rather to form new compounds, than simply 

 to detach compounds already formed by nature. Hence a ques- 

 tion may justly arise, whether the substance I have been de- 

 scribing is the real active principle of hemlock, or a new product 

 formed by the action of caustic potassa aided by heat ? 



Here it may be observed, in the first instance, that heat is not 

 necessary for the development of conia in hemlock and its pre- 

 parations ; for its peculiar odour is at once disengaged from the 

 powder of the seeds when treated with solution of potassa at or- 

 dinary atmospheric temperatures. 



By far the most direct and satisfactory test, however, of the 

 force of the above objection in such circumstances, is the effect 

 of the detached principle on the animal body, and the relation the 

 phenomena bear to those produced by the crude substance from 

 which the principle is obtained. In the present case experiment 

 amply proves, that the conia of Geiger concentrates in itself the 

 properties of hemlock, — and, if not itself the true active principle, 

 must contain it in large quantity. 



The researches of Geiger on this head are few in number, and 

 were chiefly confined to small birds as the subject of experiment. 



3 d 2 



