CHEMICAL SCIENCE. 241 



on the top is perfectly clear, decant some of it into a capsule, and 

 leave it in a r> ; r// dry place to spontaneous evaporation. 



Now, two orders of things may present themselves either the 

 alkaloid contained in the suspected matter is liquid and volatile, or 

 solid and fixed. I shall now consider these two hypotheses. 



Examination for a Liquid and Volatile Alkaloid. We suppose 

 there exists a liquid and volatile alkaloid. In such a case, by the 

 evaporation of the ether, there remain in the inside of the capsule 

 some small liquid striae, which fall to the bottom of the vessel. In this 

 case, under the influence of the heat of the hand, the contents of the 

 capsule exhale an odor more or less disagreeable, which becomes, 

 according to the nature of the alkaloid, more or less pungent, suffo- 

 cating, irritant ; it presents, in short, a smell like that of a volatile 

 alkali, masked by an animal odor. If we discover any traces of the 

 presence of a volatile alkaloid, we add then to the contents of the 

 vessel, from which we have decanted, a jsrnall quantity of ether, 1 or 

 2 fluid drachms, of a strong solution of caustic potash or soda, and 

 agitate the mixture. After a sufficient time, we draw off the ether 

 into a test-tube, exhaust the mixture by two or three treatments with 

 ether, and unite all the etherial fluids. We pour afterwards into this 

 ether, holding the alkaloid in solution, 1 or 2 drachms of water, acidu- 

 lated with a fifth part of its weight of pure sulphuric acid, agitate it 

 for some time, leave it to settle, pour off the ether swimming on the 

 top, and wash the acid liquid at the bottom with a new quantity of 

 ether. As the sulphates of ammonia, of nicotine, aniline, quinoleine, 

 picoline, and petiuine are entirely insoluble in ether, the water acid- 

 ulated with sulphuric acid contains the alkaloid in a small bulk, and 

 in the state of a pure sulphate ; but as the sulphate of coniine is 

 soluble in ether, the ether may contain a small quantity of this alka- 

 loid, but the greater part remains in the acidulated watery solution. 

 The ether, on the other hand, retains all the animal matters which it 

 has taken from the alkaline solutions. If it, on spontaneous evapora- 

 tion, leaves a small quantity of a feebly colored yellowish residue, of 

 a repulsive animal odor, mixed with a certain quantity of sulphate of 

 coniine, this alkaloid exists in the suspected matter under analysis. 

 To extract the alkaloid from the solution of the acid sulphate, we 

 add to the latter an aqueous and concentrated solution of potash 

 or caustic soda ; we agitate and exhaust the mixture with pure ether ; 

 the ether dissolves ammonia, and the alkaloid is now free. We 

 expose the etherial solution at the lowest possible temperature to 

 spontaneous evaporation ; almost all the ammonia volatilizes with the 

 ether, whilst the alkaloid remains as residue. To eliminate the last 

 traces of ammonia, we place, for a few minutes, the vessel containing 

 the alkaloid in a vacuum over sulphuric acid, and obtain the organic 

 alkaloid, with tlio. chemical and physical characters which belong to 

 it, and which it is now the chemist's duty to determine positively. I 

 applied the process which I have described to the detection of nico- 

 tine in the blood from the heart of a dog poisoned by 2 cubic centims. 

 (0.78 cubic inch) of nicotine introduced into the esophagus; and 



