OLEUM LINI 



253 



slightly bitter. Flaxseed meal is of a brownish-gray color, and has 

 a slight odor. 



Powder. Characteristic elements: See Part iv, Chap. I, B. 



CONSTITUENTS. A viscid yellow fixed oil, 30 to 35 per cent., proteids 

 25 per cent., resin, wax, a small quantity of amygdalin. The powder 

 upon extraction with petroleum should yield not less than 30 per 

 cent, of fixed oil, 98 per cent, of which should be saponifiable. An 

 althaea-like mucilaginous substance resides in the epithelial layer, 

 which swells considerably in water. This gummy matter from the 

 investing coat is rapidly imparted to hot water, forming a thick, 

 viscid mucilage, precipitated by alcohol and lead subacetate. The 

 gummy principle is considered as transformed starch, which latter 



FIG. 137. Cross-section of Flaxseed. a. Epithelium, b. Epidermal cells in swollen condition . 

 c. Stone cells, d. Layer of collapsed cells for building stone cells, e. Pigment coat. /. Containing 

 oil. 



exists in the immature seed, but is absent in the ripe seed. Ash, not 

 exceeding 6 per cent. 



264 a. OLEUM LINI. A yellowish fixed oil expressed (for medicinal use) 

 from the seed without heat, having a slight, pleasant odor, and a 

 bland. taste; on exposure to the air it gradually thickens and acquires 

 a strong odor and taste. The oil used in the arts is obtained on a 

 large scale by roasting the seeds before being pressed, in order to 

 destroy the gummy constituents of the coating. It does not congeal 

 above 20C. ( 4F.). The most characteristic principle in the 

 oil is linolein, CnH^O^, a glyceride of linoleic acid, and considered 

 to be a mixture of two acids linolic, CisH^C^, and linolenic acid, 

 CisHaoOg. The drying property of the oil resides in this constituent. 





