304 



obtained by recrystallising (containing always traces of the crystal- 

 line body) or tlie original aqueous solution of the ethereous extract 

 (if no crystalline body lias been obtained from it by evaporating) 

 is concentrated to about 50 grammes and tested with the following 

 chemicals. For every experiment only 10 to 15 drops are 

 employed, and the reagent is only added drop by drop. 



Liquor of ammonia. — It effects either a darker tinge without 

 cloudiness or it produces turbidity. The first reaction is common 

 with all organic coloured matters under the influence of alkalies; 

 the latter indicates with tolerable certainty the presence of an 

 alkaloid, and if such a body has been obtained previously by crys- 

 tallisation, and should have }>roved precipitable by ammonia, the 

 precipitate obtained from the mother-ley is only a rest of it. 



If ammonia has effected a precipitate in the sample, the whole 

 liquid is ti-eated in the same way; the precipitate is collected on a 

 filter, washed with water, and examined as under B, a. Evaporate 

 the filtered liquid and the water used in washing to the original 

 bulk, in order to drive off the ammonia, and proceed further as 

 below. Proceed likewise and at once if ammonia has produced no 

 turbidity in the sample. 



Carhoiu(,te of ammonia. — All that has been said about liquor of 

 ammonia applies also to this test. 



Leys of potash or of soda. — They effect usually a darker colour- 

 ation than ammonia. A turbidity produced by any of them may 

 be an alkaloid, or lime, or magnesia, inasmuch as small quantities 

 of the salts of these bases pass always into the ethereous extract of 

 vegetable substances. If it be lime or magnesia, the cloudiness 

 does not disappear after shaking the sample with twice its volume 

 of alcohol of 90 or 95 7„. 



The precipitate may also be a mixture of an alkaloid and of 

 alkaline earths. In this case its quantity is diminished by the 

 alcohol. To make sure of it, filter the alcoholic liquid, evaporate 

 almost to di-yness, redissolve in a little water with aid of one or 

 two drops of hydrochloric acid, and add potash-ley. Should the 

 liquid remain clear now, no alkaloid was pi'esent; if a ttu-bidness 

 is produced, an alkaloid is present, and this one not precipitable 

 by ammonia (as it would have been indicated before by that same 

 reagent). 



If the precipitate produced by the fixed caustic alkali has been 

 proved an alkaloid or a mixture of it, the whole liquid must be 

 treated with the alkali. Collect the precipitate in a filter, shake 

 with alcohol, if only partly soluble in it, filter, evaporate, and 

 examine as under B, a. The liquid separated from the precipitate, 

 and the water used for washing, ai-e saturated with acetic acid, are 

 then concentrated to the former volume and examined as below. 

 If the ley has had no precipitating effect, i:)roceed at once to the 

 next test. 



