CALCIUM OXALATE. 135 
CaHPO,+2H,0, is found abundantly in a crystalline form’ 
in the Indian Yeak-wood (Tectona grandis L., Nat. Ord. Ver- 
benacee). Calcium carbonate, which is contained in some 
plasmodiums, in the cell-membranes of many marine alge, and. 
in cystoliths (Ficus, Cannabis, Humulus*), does not show dis- 
tinctly crystalline forms,’ or is manifestly amorphous. Crystals 
of gypsum appear not to be present in plants; since they are 
soluble in 400 parts of water, the conditions are probably want- 
ing for their formation and maintenance. 
Crystals of organic compounds, which are met with in the 
tissues of drugs, are, however, no rarity. Thus, asparagin, 
cubebin, hesperidin, picrotoxin, theobromine, and piperine, 
which, however, may be presumed to first crystallize during» 
the process of drying the respéctive drugs. Furthermore, crys- 
tallized fats, probably for the most part palmitin and stearin, 
which are found in many seeds, as, for instance, in the nutmeg, 
in Cocculus Indicus, ete. Finally, vanillin in the parenchyma 
and upon the outer surface of the Vanilla (Fig. 83). The erys- 
tals which become visible in Cinchona barks, after warming their 
sections in caustic alkali, first appear as a result of this treat- 
ment. By very long preservation in glycerin of sections of tis- 
sues rich in tannin, crystals of gallic acid also occasionally 
appear, which were not originally present. After a very long 
preservation of the respective sections, one may also observe the 
gradual crystallization of amygdalin, filicic acid, and strychnine.. 
Small granules are frequently found deposited in cells, which 
acquire with ferric chloride in aqueous, or often better in alco- 
holie solution, a blue or greenish coloration, so that we may con- 
sider them as tannin, or as tannin-like formations. On the other 
hand, they also often become colored blue by iodine, as if they 
' Kopp-Will’s Jahresbericht der Chemie, 1860, p. 531, and 1879, p. 937; 
“Berichte der Deutschen Chemisch. Gesellschaft,” 1877, p. 2,234.—Com- 
pare further Just’s Bot. Jahresbericht, 1881, I., 402, Reference No. 75. 
* Fliickiger, ‘‘Pharmakognosie,” 1883, 710; Sachs, “Lehrbuch der 
Bot.,” 1874, 70; Kny, ‘‘ Botan. Wandtafeln.” 
*Thus also the aggregates in Castoreum; compare Fliickiger, 
Grundriss der Pharmakognosie,” 1883, 237; further Just’s Bot. Jahres- 
rericht, 1881, I., 402, 403. : 
