274 



HA RD WICKE' S SCIENCE- G OSSIP. 



in the seeds, but is formed by the chemical union of 

 the substances mentioned above. This oil is very 



no acridity, and has been used as a purgative. The 

 use of mustard as a medicine dates from very early 



Fig. 157, —Portion of Clobba bulbi/era, showing buds and true flowers on the same axis. (See page 251.; 



^^^-^ 



Fig. 158. — Glolba bulbi/era. 

 One of the buds more 

 advanced 



,*Sfe) 



Fig. x^g.^Salvadora persica. 

 Flower magnified. 



acrid, and has been employed as a rubefacient, while 

 the fixed oil obtained by pressure from the seeds has 



Fig. 160, — Salvadora perstca. 



times. Hippocrates is said to have used it as a 

 medicine. In modern use it is employed as a 



