ALKALOIDS. 615 



Meconic acid, C 7 H 4 O 7 .3H 2 O. A tribasic acid, characteristic of 

 opium, in which it exists to the extent of 3 or 4 per cent., most 

 likely combined with the alkaloids. It is a white, crystalline sub- 

 stance, soluble in water and alcohol. 



Meconic acid forms with ferric chloride a blood-red color, which is 

 not affected by dilute acids or by mercuric chloride (different from 

 ferric sulphocyanate), but disappears on the addition of stannous 

 chloride and of the alkali hypochlorites. This test may be used in 

 cases of poisoning to decide whether opium or morphine is present. 



Hydrastine, Hydrastina, C 21 H 21 N0 6 = 380.32. Found together with ber- 

 berine in the rhizome of Hydrastis Canadensis (golden seal) in quantities vary- 

 ing from 0.1 to 0.2 per cent. Hydrastine crystallizes in four-sided, colorless 

 prisms ; it fuses at 131 C. (268 F.), is insoluble in water and benzin, soluble 

 in about 2 parts of chloroform, 124 parts of ether, and 135 parts of alcohol at 

 the ordinary temperature. 



Hydrastine answers to all the. general tests for alkaloids; treated with con- 

 centrated sulphuric acid it shows a yellow color, turning red, then purple on 

 heating. Concentrated nitric acid produces a yellow color, changing to orange. 

 The fluorescence noticed in solutions of hydrastine or its salts is due to pro- 

 ducts formed from it by oxidation. While hydrastine itself crystallizes very 

 readily, especially from solutions in acetic ether, its salts can scarcely be 

 obtained in crystals. 



Hydrastinine, C 11 H 11 NO 2 . When hydrastine is treated with 

 oxidizing agents it is converted into hydrastinine, the hydrochloride 

 of which is official. This salt has a pale-yellow color, a bitter, saline 

 taste, and is soluble in 0.3 part of water, and also readily soluble in 

 alcohol, but difficultly soluble in ether or chloroform. A dilute 

 aqueous solution of the salt (up to about 1 in 100,000) has a decided 

 blue fluorescence. 



Berberine, C 20 H 17 N0 4 . Found in a number of plants (Berberis Tulgaris, 

 Hydrastis Canadensis, etc.) belonging to entirely different families. It is a 

 yellow, crystalline substance, soluble in 7 parts of alcohol, 18 parts of water, 

 insoluble in ether, chloroform, and benzene. 



Berberine not only forms well-defined, readily crystallizing salts with acids, 

 but it also enters into combination with a number of other substances, as, for 

 instance, with alcohol, ether, chloroform, etc. Some of these compounds crys- 

 tallize well, as for instance, berberine-chloroform, C 20 H 17 NO 4 .CHC1 3 . 



The xanthine alkaloids. 



Caffeine and theobromine are xanthine derivatives and are closely 

 connected with uric acid. They show the properties of alkaloids to 

 a much less degree than the majority of the compounds considered in 

 this chapter ; they do not act on red litmus and are but feebly basic. 



