196 VETBKINAEY MATERIA MEDICA. 



TOPICAL AGENTS. 



EUBEFACIBNTS, VESICANTS, AND PUSTULANTS. 



Sinapis, Mustard (syn. — Semen Erucse). The 

 seeds of Sinapis alba — English or yellow mustard; 

 and of Sinapis nigra — black or German mustard; 

 natural order Cruciferse. Are annual plants. Differ- 

 ent varieties grow wild in Europe and North Amer- 

 ica, and are frequently used to adulterate the better 

 sorts. 



Composition of Mustard. 



a I 



02 



13 



'A a 

 a ° 



Sinalbin 



Myrosin, a ferment. 



Sinapine, an alkaloid. 

 A bland, fixed oil. 

 Ei'ucic or brassic acid. 



Acrinyl sulphocyanate is the 

 rubefacient principle, pro- 

 duced by reaction between 

 these two in the presence of 



water. 



Sinigrin (potassium f ^^^ «"lP'i°«ya"/'ie, the vola- 



mvronate) ^'^^ °'l °? "^"stard, produced 



Myrbsin, a ferment. by reaction of these two in 



•' ' I, the presence of water. 



Sinapine, an alkaloid. 

 A bland, fixed oil. 

 Erucic or brassic acid. 



Mustard is used internally as a stomachic, carmi- 

 native, stimulant, and emetic; slightly diuretic and 

 laxative. Large doses are irritant. Externally as 

 a rubefacient, vesicant, and suppurant. If mustard 

 paste is rubbed upon the skin of a horse it causes 

 redness, heat, tenderness, and some swelling in about 

 twenty minutes. If allowed to remain on, vesication 



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