78o BOTANY AND PHARAIACOGNOSY. 



opium masses), wiLh prominent, brown-colored fibrovascular tissue 

 composed of spiral tracheae and narrow sclerenchymatic fibers ; 

 parenchyma of seeds colorless, containing air ; epidermal cells 

 with large, elliptical, oblique pores ; taste bitter ; sparingly soluble 

 in water or potassium hydrate solution. The Smyrna opium has 

 the largest number of epidermal cells of capsule, the Indian few 

 or none and the Persian very few. The Persian always has an 

 appreciable amount of starch. 



198. GO A POWDER is formed as a result of pathological 

 changes in the woody tissues of Vonacapona Araroba (Fam. 

 Leguminosse), a forest tree of Brazil. It is obtained by cutting 

 down the trees, splitting the trunk and removing the powder 

 from the clefts or cavities. When fresh the powder is of a light 

 yellow color, but on exposure to air it becomes dark brown or 

 brownish-purple. It is composed of small, wine-colored, some- 

 what translucent, irregular, angular fragments, with a few 

 fragments of tracheae and libriform cells with bordered pores. It 

 is nearly insoluble in water, soluble in alcohol, chloroform and 

 solutions of the alkalies, the latter being colored deep red and 

 showing a green fluorescence. It should contain between 50 and 75 

 per cent, of a neutral principle, chrysarobin, which is official. The 

 latter is a crystalline yellow substance. Chrysarobin forms a red 

 colored solution with solutions of the alkalies (due to the forma- 

 tion of chrysophanic acid) or sulphuric acid; on pouring the 

 sulphuric acid solution into an excess of water the chrysarobin is 

 re-deposited. Goa powder also contains about 2 per cent, of resin ; 

 7 per cent, of bitter extractive ; a small amount of chrysophanic 

 acid, and yields about 3 per cent, of ash. Alounts of the powder 

 sometimes show colorless prismatic crystals. 



B. WITHOUT CELLULAR TISSUES. 

 a. POSSESSING OIL. 



199. ASAFETIDA. In a glycerin mount the powder shows 

 irregular grayish (or gray streaked with brown) masses; these 

 are opaque and become milky white on the edge from the pres- 

 ence of oil. The stony asafetida is pulverulent and contains less 

 oil (p. 671). 



