POWDERED DRUGS AND FOODS. 745 



79. LINUM (Linseed or Flaxseed Meal). — Lemon-yellow 

 (Figs. 99, A; 184; 293) ; fragments of seed-coat with muci- 

 laginous epidermal cells; a sub-epidermal tissue composed of 

 two rows of yellowish cells with rather large intercellular 

 spaces; a layer of sclerenchymatous fibers, which are 100 to 

 250 IX long and about 10 /i, in diameter and with numerous simple 

 pores ; several layers of obliterated cells ; and a layer of pigment 

 cells which are more or less tabular or polygonal, tangentially 

 elongated and with a reddish- or yellowish-brown pigment, which 

 is colored dark blue with ferric chloride. The endosperm is made 

 up of 2 to 6 layers of cells containing oil and difficultly distinguish- 

 able protein grains. The embryo contains considerable oil and 

 large aleurone grains 10 to 20 ;u in diameter, the crystalloids of 

 which can be more readily discerned on treating the material first 

 with chloroform and then mounting it in iodine solution. Flax- 

 seed does not contain starch and the commercial product should 

 not show more than 10 starch grains to a milligram of powder; 

 it should yield not less than 30 per cent, of a saponifiable oil, and 

 not more than 3.5 per cent, of ash. 



Ground flaxseed is sometimes infested by maggots. In order 

 to obviate this it should be recently prepared and carefully pre- 

 served in tin cans with the addition of a few drops of chloroform. 



Allied Plant. — In False Flax {CamcUna sativa) of Europe, 

 the sclerenchymatous fibers are replaced by broad, short stone 

 cells, and the epidermal cells on the addition of water eject a 

 central column of mucilage. 



80. CYDONIUM. — Yellowish-red or reddish -brown ; frag- 

 ments of seed-coat with polygonal, mucilaginous epidermal cells, 

 the walls of which are readily stained with methylene blue; a 

 number of rows of sclerenchymatous fibers with strongly thick- 

 ened walls and brown contents ; several layers of elongated, thin- 

 walled cells resembling the " tube cells " in cereals ; a colorless 

 layer with minute starch grains ; and an inner epidermis, the cells 

 of which contain a brown pigment. The perisperm consists of 

 several layers of more or less obliterated cells. The outer layers 

 of the endosperm, as well as the cells of the embryo, contain 

 aleurone grains and a fixed oil. The structure of quince seed 

 resembles" quite closely that of pear and apple seeds. 



