552 SCIENTIFIC AND APPLIED PHARMACOGNOSY 



of bast fibers and laticiferous cells in an interrupted circle; middle 

 bark with large groups of stone cells, varying from nearly isodiametric 

 to elongated, sometimes very irregular in form; inner bark with 

 medullary rays 1 to 2 cells wide, numerous laticiferous cells accom- 

 panied by small groups of sieve cells, parenchyma containing either 

 starch grains or rosette aggregates of calcium oxalate, and an occa- 

 sional isolated bast fiber or small groups of stone cells. 



Powder. Light yellowish-brown ; stone cells in large groups, the 

 individual cells being more or less irregular in shape having very 

 thick, porous walls, the lumina being usually filled with air; calcium 

 oxalate chiefly in rosette aggregates, occasionally in single prisms, 

 mostly from 0.015 to 0.020 mm. in diameter; starch grains, from 

 0.003 to 0.015_mm. in diameter, mostly single, frequently 2- to 4- 

 compound; bast fibers non-lignified, very long and from 0.010 to 

 0.035 mm. in width; fragments of thin-walled latex cells from 0.015 

 to 0.025 mm. in diameter and filled with a granular substance; frag- 

 ments of cork grayish- or light yellowish-brown. 



Upon macerating 1 gm. of powdered Condurango with 5 c.c. of 

 water and filtering, the filtrate should be clear; and on boiling 

 becomes cloudy, assuming its original transparency when cool 

 (due to the properties of condurangin). 



Constituents. Several glucosidal combinations of condurangin. 

 The latter being completely soluble in cold water and precipitated 

 upon heating the aqueous solution. It is also soluble in benzene 

 and gives a green color with molybdic and sulphuric acids. /3-con- 

 durangin is also insoluble in water, but is not affected by Froehde's 

 reagent. Condurango also contains 12 per cent of tannic acid; 

 0.75 per cent of a deliquescent crystallizable acid; a yellowish-white 

 resin; a small quantity of starch; a fixed oil; a fermentable sugar; 

 and 10 to 12 per cent of ash. 



CONVOLVULACEJE, OR MORNING GLORY FAMILY 



A family of about 900 species, being very abundant in the tropics. 

 They are either herbs or shrubs, some being more or less trailing and 

 frequently climbing The leaves are alternate, the flowers have 

 gamopetalous corollas, and the fruits are capsules. A number of 

 the plants are cultivated and some of them as the common morning 

 glory (Ipomoea purpurea) are well known for their showy flowers of 

 different colors. One of the most useful plants of this family is the 

 SWEET POTATO vine (Ipomoea Batatas), a perennial herbaceous vine 



