290 VETERINARY STUDIES 



Burnt alum is common alum from which the water has been 

 driven off by heating. 



It is quite astringent, somewhat caustic, and is sometimes used 

 on excessive granulations in an open wound. 



Tannic acid (tannin). — This is a very light, yellowish pow- 

 der obtained from oak galls. It is soluble in water and glyc- 

 erin, a powerful astringent and styptic. 



It coagulates albumin, checks secretion locally where applied, 

 and is but slightly irritating. 



Tannic acid is often used on mucous membranes for its astrin- 

 gent effect in checking the local secretion, as in certain diar- 

 rheas when a non-caustic astringent is needed. Externally, tan- 

 nic acid is used on superficial collar and other harness sores, 

 dusted on as a powder, or dissolved in water or glycerin, about 

 2 ounces to the pint. Tannic acid dissolved in glycerin is very 

 useful for sore and chapped teats. 



Dose.— The internal dose is 1 to 3 drams in solution for horses 

 and cattle. Its chief use for the stockman will be for external 

 application. 



Miscellaneous 



Collodion. — Collodion is a solution of gun cotton in ether and 

 alcohol. Flexible collodion contains castor oil and Canada bal- 

 sam, also, and is better for most veterinary uses than plain 

 collodion. It must be kept in a tight bottle and not exposed to 

 an open flame. 



It is used only as an external application and is very useful 

 in minor surgery. 



When painted over a dry surface, it dries promptly and leaves 

 a thin adherent and protective covering that is not sticky. This 

 gives excellent protection against infection and minor injury to 

 superficial wounds. It is useful to cover small, clean wounds, 

 cracked and chapped teats, etc. 



Other medicines are often added in order to use the collodion 

 as a carrier. 



