616 SCIENTIFIC AND APPLIED PHARMACOGNOSY 



glandular hairs of two kinds, either with a 1 -celled stalk or a 3- to 5- 

 celled stalk, the head in each case being rather small and with 8 to 9 

 cells; stomata large and with 2 or 3 neighboring cells; epidermal 

 cells striated and somewhat granular on surface view; the cells of 

 the mesophyll with a greenish-brown content, and some of them with 

 sphenoidal microcrystals. The following leaves have been used as 

 adulterants: Chestnut (Fig. 73), cherry, rose, melilot, cabbage, 

 chicory, beet, and lappa. In the manufacture of plug tobacco 

 various other substances are added; as, licorice (Figs. 140 and 141), 

 cloves (Fig. 202), anise (Fig. 206), orris root (Fig. 46), vanilla (Fig. 

 57), tamarinds, prunes, besides other substances. 



Constituents. Tobacco leaves contain from 0.6 to 9 per cent 

 of the alkaloid nicotine; an aromatic principle nicotianin or tobacco 

 camphor, to which the characteristic flavor is due and which is 

 formed during the curing of the leaves. The dried leaves yield from 

 14 to 15 per cent of ash, consisting in large part of potassium nitrate. 



SCROPHULARIACE^;, OR FIGWORT FAMILY 



A large family, represented by nearly 2500 species of herbs, 

 shrubs or trees. The plants are characterized by having gamo- 

 petalous corollas, which are either nearly regular or usually 2-lipped, 

 the stamens being frequently didynamous, and the fruits are usually 

 capsular. Among the anatomical characteristics the following may 

 be mentioned. Neither a sub-epidermal collenchyma nor a scleren- 

 chymatous ring in the pericycle are developed. The walls of the 

 tracheae and wood fibers usually have simple pores, except when the 

 former are in contact with the parenchyma cells, bordered pores are 

 developed. Calcium oxalate is secreted in the form of small prisms, 

 octahedra or acicular crystals. The non-glandular hairs are of four 

 different kinds: (a), unicellular; (6), uniseriate; (c), unicellular, 

 having cystoliths; and (d), multicellular, or branching, as in Ver- 

 bascum and Pawlonia. The glandular hairs are of several types: 

 (a), Those having a unicellular stalk and a unicellular secreting head; 

 (6), having a 2- or more-celled glandular head; (c), peltate-glandular. 

 The mesophyll of the leaves contain not infrequently crystals of 

 carotin, or protein substances. In Scrophularia, idioblasts contain- 



(P); starch grains (S), being from 0.004 to 0.015 mm. in diameter; wood 

 fibers (W); thick-walled medullary ray cells (Af); stone cells (Si). C, 

 tangential section showing medullary ray cells (M ) ; starch (S) ; wood fibers 

 (W); stone cells (St). Drawing by Haase. 



