240 ANNUAL OF SCIENTIFIC DISCOVERY. 



matters which we extract afterwards from these liquids. The use of 

 a salt of lead presents another inconvenience, viz : the introduction 

 of foreign metals into the suspected matters, so that that portion of 

 the suspected substance is rendered unfit for testing for mineral sub- 

 stances. The successive and combined use of water and alcohol at 

 different states of concentration, permits us to search for mineral sub- 

 stances, whatever be their nature ; so that in this way nothing is 

 compromised, which is of immense advantage when the analyst does 

 not know what poison he is to look for. 



It is hardly necessary to say, that in medico-legal researches for the 

 alkaloids, we ought never to use animal charcoal for decolorizing the 

 liquids, because we may lose all the alkaloid in the suspected matters. 

 It is generally known that animal charcoal absorbs these substances at 

 the same time that it fixes the coloring and odoriferous matters. 



The above observations do not proceed from speculative ideas only, 

 but are the result of a pretty long series of experiments which I have 

 several times employed for discovering these organic alkaloids. To 

 put in practice the principles which I have thus explained, the follow- 

 ing is the method in which I propose to set about such an analysis : 

 I suppose that we wish to look for an alkaloid in the contents of the 

 stomach or intestines ; we commence by adding to these matters 

 twice their weight of pure and very strong alcohol ; * we add after- 

 wards, according to the quantity and nature of the suspected matter, 

 from 10 to 30 grs. of tartaric or oxalic acid in preference, tartaric; 

 we introduce the mixture into a flask, and heat it to 160 or 170 

 Fahr. After it has completely cooled, it is to be filtered, the insoluble 

 residue washed with strong alcohol, and the filtered liquid evaporated 

 in vacua . If the operator has not an air-pump, the liquid is to be 

 exposed to a strong current of air at a temperature of not more than 

 90 Fahr. If, after the volatilization of the alcohol, the residue con- 

 tains fatty or other insoluble matters, the liquid is to be filtered a 

 second time, and then the filtrate and washings of the filter evapo- 

 rated in the air-pump till nearly dry. If we have no air-pump, it 

 is to be placed under a bell jar over a vessel containing concentrated 

 sulphuric acid. We are then to treat the residue with cold, anhy- 

 drous alcohol, taking care to exhaust the substance thoroughly ; we 

 evaporate the alcohol in the open air at the ordinary temperature, or 

 still better, in vacito ; we now dissolve the acid residue in the smallest 

 possible quantity of water, and introduce the solution into a small 

 test tube, and add, little by little, pure powdered bicarbonate of soda 

 or potash, till a fresh quantity produces no further effervescence of 

 carbonic acid. We then agitate the whole with four or five times its 

 bulk of pure ether, and leave it to settle. When the ether swimming 



When we wish to look for an alkaloid in the tissue of an organ, as the liver, 

 heart, or lungs, we must lirst divide the organ into \ery small fragments, moisten 

 the mass with pure strong alcoholj then express strongly, and by further 

 treatment with alcohol exhaust the tissue of every thing soluble. The liquid so 

 obtained ia to be treated in the tame way as u mixture of suspected matter aiul 

 alcohol 



