POWDERED DRUGS AND FOODS. 743 



J^i. COLOCYNTHIS. Light yellow; stone cells isodiamet- 

 ric, slightly thickened, non-lignified, with large simple pores; 

 parenchymatous cells large, thin-walled, with large, simple pores. 

 The powder in which seeds are present contains numerous oil 

 globules, and the outer epidermal cells have reticulated thicken- 

 ings ; the stone cells are nearly isodiametric or irregular, with 

 straight or undulate walls, which are more or less thickened, 

 strongly lignified and with simple pores (Fig. 93). 



2. Pigment Cells Present. 



jy. SINAPIS NIGRA. Yellowish-brown (Fig. 295) ; frag- 

 ments of seed-coat with mucilaginous epidermal cells ; a single 

 layer of thin-walled, unequal sub-epidermal cells ; a layer of palis- 

 ade or stone cells (so-called " beaker cells "), thickened much the 

 same as in Sinapis alba, but of unequal height, giving a section a 

 somewhat reticulate appearance (Fig. 295, B) ; a pigment layer of 

 one or two cells which may be tabular or considerably elongated 

 tangentially and with a brown content which is colored blue with 

 ferric chloride, as in flaxseed. The endosperm and embryo con- 

 tain fixed oil and aleurone grains, these layers practically making 

 up most of the drug. Starch grains are not present in mustard 

 and the powder should not contain more than ten granules to a 

 milligram. 



Ground Black Mustard or Black Mustard Flour is usually 

 prepared from the cake which has been deprived of the hulls and 

 part of the oil. It is customary to mix some of the white mustard 

 with the black mustard, it being supposed that the excess of the 

 ferment in S. alba will change the unconverted glucoside into 

 volatile oil of mustard. It is likely, however, that the enhanced 

 quality of the product is due to the pungent and non-volatile 

 character of the oil in white mustard. 



Mustard Paste (see Sinapis alba. No. 74) is sometimes adul- 

 terated with starches. At one time this was considered to be 

 necessary on account of the pungency of the drug. 



Allied Plants. In Russian or Sarepta Mustard (Brassica 

 Besseriana) the sub-epidermal cells are scarcely apparent and the 

 stone cells are somewhat triangular on surface view. In Charlock 



