CASTOR OIL 399 



taining a brownish amorphous substance, in which is said to be 

 included calcium silicate. This is the fundamental pigment layer 

 of the seeds giving the basic color to the seeds, the mottling and 

 variations being due to the pigments in the outer walls of the epi- 

 dermal cells. A fifth layer consists of the more or less obliterated 

 perisperm cells, containing rosette aggregates, and in which are 

 included the fibrovascular bundles; the endosperm consists of an 

 oily cytoplasm and numerous aleurone grains, the latter being 

 spheroidal or ellipsoidal, about 0.020 mm. in length, and composed 

 of a large rhombohedral protein crystal and one or more globoids. 



Constituents. A fixed oil, known as castor oil, from 50 to 70 

 per cent, and consisting principally of triricinolein, together with 

 considerable ricinisolein, palmitin and dihydroxystearin. Protein 

 substances, about 20 per cent, and consisting of globulin, albumin, 

 mucleoalbumin and glycoprotein. A very toxic alkaloid, ricine, 

 which apparently is not removed in the extraction of the castor oil, 

 but remains in the oil-cake, and though it is very poisonous to cattle 

 does not affect poultry. It also contains a second alkaloid, ricinine; 

 several ferments; an ester composed of methyl alcohol and ricininic 

 acid; sugar 2.5 per cent; a bitter principle; resin; and gum. The 

 seed-coat yields 10 per cent of ash; the endosperm but 3.5 per cent. 

 Frabot has made a study of the foreign oils present in castor oil used 

 for lubricating aviation engines. Amer. Jour. Pharm., 1918, 90, 

 p. 300. 



Literature. Schlotterbeck, Beitrage zur Entwicklungsgeschichte 

 pharmakog. wichtiger Samen. Inaug.-Diss., Bern. 



CROTON. Semen Tiglii or Croton Seed. The ripe seeds of 

 Croton Tiglium (Fam. Euphorbiacea?), a small tree indigenous to 

 tropical Asia and cultivated in the tropical countries of the Eastern 

 Continent. 



The seeds resemble those of Ricinus in size and general structure, 

 except that they are not so smooth, being somewhat scaly, and have 

 an almost uniform light reddish-brown color. The caruncle is 

 usually absent in the commercial article. The perisperm layer is 

 free from calcium oxalate, and the aleurone grains of the endosperm 

 cells not infrequently have large rosette aggregates of calcium oxalate 

 in place of the protein crystals. 



Croton seeds contain from 30 to 60 per cent of a fixed oil, com- 

 posed of the glycerides of the following acids : stearic, palmitic, myris- 

 tic, lauric, oleic, tiglic, acetic, butyric, formic and valeric. Pro- 

 tein substances about 18 per cent; a very toxic albuminous sub- 

 stance, crotin, consisting of at least two principles, crotonglobulin 



