620 SCIENTIFIC AND APPLIED PHARMACOGNOSY 



Oven drying has no advantage over a reasonably rapid air drying 

 of digitalis leaves. 



The drying causes a marked deterioration when conducted in an 

 oven at a high temperature. 



The fresh drug has greater toxicity than the dried drug. 



No products more highly toxic than those present in the crude 

 drug are developed during the process of drying. 



Description. Usually more or less crumpled and broken into 

 fragments; lamina ovate-oblong or ovate-lanceolate, 10 to 25 cm. in 

 length, 5 to 15 cm. in breadth; summit obtuse or rounded; base 

 somewhat cuneate, tapering into the petiole; margin dentate or 

 crenate, the divisions with a yellowish-brown gland-like summit; 

 upper surface dark green, minutely hairy, somewhat wrinkled, with 

 a single water-pore near the summit of each tooth; under surface 

 grayish-green, midrib grayish-brown, prominent, from which veins 

 of the first order diverge at angles of 45 to 65 and unite with one 

 another near the margin, and from which arise other anastomosing 

 veins, giving a distinctly reticulate appearance; distinctly pubescent 

 on the veins and frequently on the reticulations; petiole about one- 

 third the length of the lamina or in the upper leaves nearly want- 

 ing, grayish-brown, laminated; texture fragile; odor distinct; taste 

 bitter. 



Leaves that are more than 30 cm. in length are usually rejected, 

 as also the tuft of radical leaves of the first-year plant. 



INNER STRUCTURE. See Figs. 273 to 276. 



Powder. Dark green; non-glandular hairs, uniseriate, of 2 to 8 

 (usually 2 to 5) cells, from 0.145 to 0.435 mm. in length, some of the 

 cells being frequently collapsed; glandular hairs few, small, with a 

 1- or 2-celled stalk and 1- or 2-celled glandular head; numerous 

 irregular fragments of lamina showing epidermal cells having undu- 

 late walls and scattered stomata or occasional water-pores. 



Localization of the Active Glucosides. With means of sodium 

 picrate reagent (one drop of 1 per cent picric acid solution mixed with 

 one drop of 10 per cent sodium hydroxide solution) applied to sec- 

 tions, the cells containing the glucosides are colored orange within 

 one or two minutes. In all the species of Digitalis studied, including 

 D. purpurea, lutea, ambigua, the glucosides were thus located in the 

 epidermal cells, the non-glandular hairs, in the endodermis of the 

 vascular bundles and some times in the subepiderml collenchyma. 

 The leaf margin (epidermis and endodermis) gave the strongest 

 reaction, the base of the petiole only a very faint one. Baljet, 

 Schweiz. Apoth. Ztg., 1918, 56, p. 247. 



