456 HEALTH AND DISEASE 



purposes. It is used in several forms — as a crystal of irregular shape, as 

 a powder, and as burnt, exsiccated, or dried alum, that is after it has 

 been deprived of its water of crystallization. 



Externally it is used for all the purposes to which other astringents are 

 applied, except as a styptic, as it has no very marked influence in arresting 

 haemorrhage of a serious character. In the dried form, alum is very much 

 more active than in the other conditions, and is a valuable dressing for 

 wounds, ulcers, and foetid discharges of various kinds. In combination 

 with flour and oxide of zinc it is used for cracked and chapped heels, and 

 for grease and skin eruptions upon the legs and belly. 



For injuries to the tongue, or any part of the oral cavity, alum is 

 invaluable. It has been found, in cases where the cheeks and gums have 

 been denuded of membrane, or the tongue has suffered serious laceration, 

 that a solution of alum speedily brings about the formation of a protective 

 covering. In some forms of diarrhoea, and in prolapsus of the womb or 

 bowel, it is an excellent astringent. It is also employed as an eye lotion, 

 in powder as an insufflation, and in solution as an injection up the nostrils 

 in cases of ozena. It has long been esteemed for drying up the milk of 

 mares when, through loss of the foal or other causes, it is desirable to 

 arrest the mammary secretion. 



Iron. — In addition to its great value as a tonic, iron is one of our most 

 valued astringents. There are a great many preparations of it, of which 

 the following are in most common use in veterinary practice: sulphate, 

 carbonate, and solution of perchloride. 



For arresting hsemorrhage outside the body, the solution of perchloride 

 is a most eflicient preparation. It enters into the astringent lotions em- 

 ployed in the treatment of thrush, grease, and other diseases attended with 

 foul discharges and fungoid growths. 



Copper. — The salts of copper are used in much the same way as those 

 of iron, l)ut the sulphate, which is the preparation most employed, is more 

 astringent than that of iron. In grease, thrush, and canker it is employed 

 as a lotion or in powder, either alone or in combination with other astrin- 

 gents. It has the most drying effect of any of the astringent metallic salts 

 when applied to raw surfaces. In special cases it is prescribed as an 

 intestinal astringent. 



Zinc. — The preparations of zinc used in the medical treatment of horses 

 are the sulphate, acetate, chloride, oxide, carbonate, and oleate. The salts 

 vary very much in their astringent and caustic properties. 



The oxide and carbonate are but very slightly astringent, and in this 

 connection are used only as cooling and drying agents. The acetate, sul- 

 phate, and chloride in weak solutions are astringent. 



