316 SCIENTIFIC AND APPLIED PHARMACOGNOSY 



pores and cells containing numerous spheroidal starch grains varying 

 from 0.002 to 0.020 mm. in diameter; fragments of Senna determined 

 by their characteristic, more or less curved, unicellular, non-glandular 

 hairs from 0.100 to 0.350 mm. in length, fragments of epidermis 

 with elliptical stomata and their two neighboring cells and frag- 

 ments with crystal fibers; when mounted in a fixed oil and examined 

 under the petrographical microscope it shows a large number of 

 irregular, angular fragments of sugar, which polarize light strongly 

 and are furthermore readily soluble in mounts made with water; 

 upon the addition of solutions of potassium hydroxide to aqueous 

 mounts of the powder, the fragments of Senna are immediately col- 

 ored a yellowish-red changing to a reddish-brown. On adding 0. 100 

 gm. of compound powder of licorice to a test-tube, moistening with 



2 c.c. of alcohol and then adding 10 c.c. of water and boiling, allowing 

 to cool and then filtering, the filtrate should be of a pale yellowish- 

 brown color, which, upon the addition of a drop of solution of potas- 

 sium hydroxide, changes to a yellowish-red (Senna). 



SENNA. Senna Leaves. The leaflets of various species of 

 Cassia (Fam. Leguminosse, sub-fam. Csesalpinaceae), small shrubs 

 indigenous to upper Egypt and southern Arabia. There are two 

 important commercial varieties: (1) Alexandrian Senna, derived 

 from wild plants of Cassia acutifolia, a small shrub (Fig. 142) growing 

 in the region of the Nile River from Assouan to Kordofan, and 

 exported by way of Alexandria and Red Sea ports; (2) Indian or 

 Tinnivelly Senna derived from cultivated plants of Cassia angus- 

 tifolia, growing on the east African coast, in Arabia and north- 

 western India, and cultivated in southern India. The leaves are 

 carefully collected and dried, the Tinnivelly variety being more 

 largely used, although the Alexandrian is more highly esteemed. 



Alexandrian Senna. Lanceolate or ovate-lanceolate; 1.5 to 



3 cm. in length, 5 to 8 mm. in breadth; summit acute mucronate; 

 base unequal, acute; margin entire; upper surface pale green, 

 nearly glabrous, midrib sometimes depressed, veins of first order 

 more or less prominent, under surface light grayish-green, midrib 

 prominent, minutely pubescent, especially near the veins; petiolule 

 about 1 mm. in length; texture coriaceous, fibrous; odor slight; 

 taste somewhat bitter. 



Inner Structure. Similar to that of Indian senna (Fig. 143). 



Powder. Light green; fragments colored reddish with solutions 

 of the alkalies; non-glandular hairs, 1-celled, pointed, often curved, 

 from 0.100 to 0.350 mm. in length, walls thick and papillose; cal- 

 cium oxalate in rosette aggregates, from 0.009 to 0.010 mm. in diam- 



