106 VETERINARY MATERIA MEDICA. 



TOPICAL AGENTS. 



Rubefacients, 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. 



re r Sinalbin. 



Acrinyl sulphocyanate is the 

 rubefacient fn-inciple, pro- 



^ , 1 Myrosin.'aferineDt: j diiced by reaction between 

 < n \ I these two in the presence of 



.^^•| \ I water 



CO g 

 .1: o 



C3 



to I 

 \n CO 

 ^ c 



a ^ 

 .9 u 



m 



Sinapine, an alkaloid. 

 A bland, fixed oil. 

 Erucic or brassic acid. 



^.. . . , ^ . f Allyl siilphocyauide, the vola- 

 Sinigrin (potassium ! ^^^ ^-j ^^ mustard, produced 



myronate) . \ ^^ reaction of these two in 



Myrosm, a ferment. '^ ^^^^ 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 



