ACTION AND USES OF MEDICINES. 145 



tions they draw from the system, and partly by the nervous prostration 

 they induce. 



Purgatives, therefore, should not be given to a horse in a weak state, 

 because he cannot bear further weakening ; nor, except in very reduced 

 quantities and with the greatest caution, in diseases of the lungs or air- 

 passages. In these cases the animal is always weak on account of the 

 blood not being properly purified in the lungs. And, again, on account 

 of the active sympathy existing between the mucous lining of the air- 

 passages and that of the alimentary canal, there is always reason to fear 

 that the inflammation already established in the one may extend to the 

 other. Under such circumstances physic is very likely to cause super- 

 purgation. 



287. Aloes. 



Aloes is by far the best and safest purgative. Cape and Kast India are 

 inferior to Barbadoes, chiefly on account of the greater proportion of 

 resinous matter they contain. Aloes is usually and most conveniently 

 given in the solid form as a ball. Four or five drachms are a sufficient 

 dose for most horses, if properly prepared ; but large heavy horses may 

 perhaps require five or six. It usually operates in about twenty-four 

 hours. 



The following prescriptions for an Aloetic mass are recommended in 

 preference to those made up with oils or other fats : 



Barbadoes Aloes ..... 8 parts. 



Glycerin 2 parts. 



Powdered Ginger ..... 1 part. 

 Melt together in a water bath and thoroughly incorporate. 

 Dose from 6 to 8 drachms. 



or 

 Barbadoes Aloes . . . . , . 1 lb. 



Treacle . . ,- . . . 1 lb. 



Ginger o oz. 



Melt in a water bath and stir while coolin"'. 

 Dose from 8 to 12 drachms. 



In cases where the use of ginger is considered objectionable, the same 

 quantity of powdered gentian may be substituted. The action of the 

 medicine w^ill be slightly increased. 



Aloetic medicine should not be made up in balls until required for use, 

 but should be kept in a mass in a glass-stoppered bottle. When divided 

 into small portions, as in balls, it soon becomes drv' and hard, and is then 

 uncertain in its effects. A single ball can be made up by reducing the 

 aloes (4 or 5 drachms) to powder in a mortar, and adding 2 drachms of 

 ginger with sufficient treacle to form a soft mass. The ball must then be 

 wrapped in soft paper. 



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