6o VEGETABLE DRUGS WITHOUT ORGANIC STRUCTURE. 



The specific gravity is about 1.20 and it melts at about 

 85° C. It is insoluble in water, soluble in alcohol, with 

 brownish yellow color, also soluble in amyl alcohol, 

 chloroform, acetone and caustic alkalies ; sparingly soluble 

 in oil of cloves and cumarin. Practically insoluble in 

 petroleum ether, benzol, or carbon disulphide. The 

 alcoholic solution has a slight acid reaction, and by oxi- 

 dation becomes blue or green, which color is also more 

 rapidly developed on the addition of ferric chloride or 

 other oxidizing agent, as chlorine, iodine, or bromine. 



The resin consists of (a) Guaiaconic acid, C^Ji^fi^ 

 (OH) 2, which makes up about 70 per cent, of the resin. 

 It is amorphous, bright brown, odorless and tasteless, 

 melts at 95° to 100° C, is insoluble in water, easily soluble 

 in alcohol, ether, acetic acid, and chloroform. The salts 

 are amorphous, the alkali salts soluble in water and alcohol. 



(b) Guaiaretic acid (Guaiac resin acid, CjgHj 8(00113)2 

 (011)2), about 10 per cent. From alcoholic solution it 

 crystallizes out as rhombic needles, which have a slight 

 vanilla-like odor, melts at 75° to 80° C, is insoluble in 

 water, soluble in ether, chloroform, acetic acid, benzol. 

 Its alkaline salts are crystalline and are soluble in water. 



(c) Guaiac beta resin; C 2 oHj 904(011)3, about 10 per 

 cent. Insoluble in ether. 



(d) Guaiac acid; CgHgOg, sparingly found. 



(e) Guaiac yellow; C20H20O7, the yellow coloring- 

 matter of the resin, odorless, bitter, easily soluble in 

 alcohol, ether, carbon disulphide. 



By destructive distillation a number of products are 

 obtained. Tiglin aldehyd, CH(CH3); guaiacol, CgH^- 

 (0H)(0CH3), and pyroguaiacin, C,2H,,(OH)(OCH3), and 

 creosol, CeH3(OH)(OCH3)(CH3), are among the most 

 important. 



Adulterations. — Guaiac is frequently adulterated by 

 colophonium; its turpentine odor is usually sufficient to 

 detect the sophistication. 



