ANTISPASMODICS — ARSENIC. 31 



senic kept, the white and the yellow. The 

 latter is a combination of white arsenic and 

 sulphur, either natural or artificial, varying 

 in colour according to the proportion of 

 sulphur, which, when considerable, gives it 

 an orange or red colour ; it is then called 

 realgar^ and used as a pigment only. 



White arsenic is obtained in the process 

 of roasting certain ores. The arsenic sub- 

 limes, and is found in chimneys adapted to 

 the purpose. It is beautifully white and 

 very heavy, but easily reduced to a powder. 

 The powdered arsenic of the shops is gene- 

 rally adulterated, and ought never to be de- 

 pended upon. The practitioner should al- 

 ways buy it in the lump, and either powder 

 it himself or see it done. 



White arsenic is one of the best tonics m 

 horses that we are acquainted with ; and, 

 though a violent poison in the human system, 

 may be given to this animal with perfect 

 safety. From its tonic quality it has often 

 suspended, or apparently cured, the glan^. 

 ders ; but its effect in this way, I believe, is 

 never permanent. It is prudent to. begin 

 with a small dose, but not less than eight 

 grains. This may be gradually increased to 



C 4 



