MATERIA MEDICA AND THERAPEUTICS. 237 



the paste made with water arid rubbed into the skin of horses, 

 produces its effects within '20 minutes ; in 2 to 6 hours vesication 

 occurs, pustules may occur where the paste is used very strong, 

 or closely repeated, or too much friction has been used. 



The volatile oil of mustard is a very powerful vesicant and 

 acts very quickly. 



Uses. — One or two teaspoonfuls in 1 or 2 ozs. of warm wa- 

 ter makes a very good emetic for dogs. 



It is used as a counter-irritant in sore throats, laryngitis or 

 pharyngitis, bronchitis, pneumonia, and pleurisy, or wherever a 

 counter-irritant is indicated ; applied in 'he early congested stages 

 it lessens the pain and relieves difficult breathing, besides reflexly 

 limiting the amount of blood in the parts ; it thus limits or de- 

 creases the inflammatory action ; also useful in the exudative 

 stages of these diseases ; to promote the absorption of the exudate 

 and thus hasten resolution, or where these diseases remain dorm- 

 ant; also arouses a depressed nervous system and reflexly stimu- 

 lates the heart ; can be used in spinal diseases or in congestion of 

 the kidneys. 



It acts best when applied and left on 20 or 30 minutes, then 

 wash off and repeat in an hour or two ; also used in acute indiges- 

 tion, applied to the abdomen ; also in colic, enteritis and peritoni- 

 tis ; in phlebitis mustard can be used but a cantharides blister is 

 better. In making a mustard plaster, take the pure mustard and 

 gradually pour in warm water (but not hot) ; can also' be made 

 with cold water or vinegar; rub in with moderate friction. 



Prescription for counter-irritant. 



Ijf 01. Sinapis, 3 j. 



Aq. Ammon. Fort., 3 ss. to 3 j- 



Ol. Olivx, B iv. 



M. Sig. — Apply once only. (If to be repeated, weaken it.) 



PIX LIQUID A— TAR. 



An empyreumatic (obtained by the aid of great heat) oleo- 

 resin obtained by the destructive distillation of the wood of vari- 

 ous, species of pines, especially that of Pinus palustris. 



Tar consists of a mixture of resinous and volatile principles. 

 When it is subjected to redistillation, it can be separated into a 

 fixed portion, — pitch, — consisting mainly of resin (rosin) ; and 



