482 SCIENTIFIC AND APPLIED PHARMACOGNOSY 



and with a slender carpophore attached to each, the latter 5-angled 

 in cross-section, the commissural surface with 2 vittse, the dorsal 

 surface with a vitta between each of the primary ribs; seeds irregu- 

 larly oblong in section, with a small embryo at the upper end of the 

 reserve layer; odor and taste aromatic. 



Inner Structure. (Fig. 207.) An epidermal layer of nearly 

 rectangular cells having thick outer walls; several rows of tangentially 

 elongated parenchyma cells, frequently more or less collapsed; a 

 single, large, elliptical, brown, vitta or oil secretory canal between 

 each of the ribs and surrounded by small epithelial or secretion cells ; 

 in each of the ribs a single fibrovascular bundle surrounded by a 

 layer of thick-walled sclerenchymatous fibers; inner epidermis of 

 broadly elongated cells with very thin side-walls being very fre- 

 quently broken and closely coherent with the more or less brownish, 

 collapsed cells of the seed-coat; commissural surface with 2 large 

 vittse and at the middle portion 2 large transverse hollow spaces 

 formed by the separation of the tissues of the seed-coat on one side 

 and the pericarp on the other, otherwise the cells resemble those on 

 the dorsal surface; endosperm large, cells polygonal with thick walls 

 and containing a fixed oil and aleurone grains, the latter usually 

 containing a small rosette aggregate or prism of calcium oxalate. 



Powder. Yellowish-brown or dark brown; cells of endosperm 

 with aleurone grains, each usually containing a rosette aggregate of 

 calcium oxalate from 0.0005 to 0.001 mm. in diameter; fragments 

 with light yellow vittse, together with nearly isodiametric or polyg- 

 onal, yellowish-brown, inner epidermal cells of pericarp; fragments 

 with tracheae and sclerenchymatous fibers, the latter about 0.010 mm. 

 in width, slightly lignified and with numerous oblique pores. 



Constituents. Volatile oil from 5 to 7 per cent; fixed oil; tannin; 

 calcium oxalate, and 5 to 8 per cent of ash. 



Volatile oil of caraway contains 50 to 60 per cent of d-carvone 

 (carvol), and 40 to 50 per cent d-limonene (carven). Caraway oil, 

 particularly carvone, is colored yellow on exposure to air, and the 

 old oil gives a reddish-violet color with ferric chloride solution. 



Standard of Purity. Caraway, caraway seed, is the dried fruit of 

 Carum carvi L. It contains not more than 8 per cent of total ash, 

 nor more than 1^ per cent of ash insoluble in hydrochloric acid. 

 (U. S. Dept. Agric.) 



Allied Drugs. The seeds of Nigella sativa and N. damascena 

 (Fam. Ranunculaceae), are used in medicine and for flavoring like 

 caraway. They are commonly known as Black Caraway. The 

 seeds are ovoid, 3- to 4-angled, about 3 mm. in length, externally 



