Castela. Castela Nicholsoni texana Jorrey and Gray. (Fam. Simarubaceae.)—This plant, which is known among the Mexicans as Chaparro amargosa, that is, bitter bush, has been highly recommended by Nixon (J. A. M. A., 1916, lxvi, p. 946) in the treatment of amebic dysentery. He found that a detannated fluidextract in the proportion of one part in a million was sufficient to cause the Entamoeba histolytica to become immobile and to assume a spherical shape, with sharp differentiations of ectoplasm and endoplasm. In ordinary diarrhea or in helminthiasis he found the drug of no value.
Putegnat (N. R., 1883, xii, p. 102) has separated a bitter principle, amargosin, which, however, is of doubtful importance. Nixon preferred a decoction of the drug, but the fluidextract is upon the market and may be given in doses of one to three fluidrachms (4.0-12.0 mils).