452 HEALTH AND DISEASE 



certain forms of sore throat due to septic matter. The growth of dele- 

 terious organisms is checked by its presence outside the body, and in this 

 connection it may be reasonably assumed that its activity is still continued 

 when introduced into the living organism. 



Quinidine, cinchonine, and the other alkaloids of cinchona bark are 

 credited with the same medicinal powers, but not in the same degree. 

 It is possible that the combination of them with quinine in some way 

 exerts a better influence than quinine alone, as there are many good 

 observers who claim to get better therapeutical results from a tincture 

 of the bark, than from the latter given as a powder. 



Salicine, when obtained from willow bark, is an expensive agent in 

 the large doses required for horses. The bark of the poplar-tree and the 

 flower-buds of the meadow-sweet also contain it, but not in sufiicient pro- 

 portion to be of any practical value as a source of supply. 



Salicylic Acid is obtained by passing a stream of carbonic acid 

 through a heated mixture of caustic soda and carbolic acid, but its natural 

 source of supply is from the oils of winter-green or sweet birch. 



Actions and Uses. — In the reduction of high temperatures and the 

 treatment of rheumatism it is the most active remedy known. Some of 

 the obscure lamenesses of a shifting and intermittent character have been 

 quickly banished by its use. Salicine and salicylic acid appear to act in 

 much the same way as quinine, and excessive doses produce the same train 

 of symptoms. 



Salicylate of Soda is very much employed in reducing temperatures, 

 but its liability to excite abnormal action of the heart requires special care 

 and observation wdiere its use is to be continued. 



MEDICINES WHICH ACT ON TISSUE CHANGE 



ALTERATIVES 



Alteratives comprise a number of drugs of importance to the horse 

 owner. It has been previously stated that they alter the nutrition of the 

 body and bring about certain desired results, not only in relation to disease, 

 but also in the process of training the horse in health for particular pur- 

 poses. These results are obtained without any marked action upon any 

 particular organ. It is supposed that alteratives act by inducing minute 

 chemical changes in the economy which are quite inappreciable by ordinary 

 methods of observation, but yet of a more or less lasting character. If 

 given medicinally, their action may remain permanent, but an animal 

 artificially "prepared" or got up for show purposes, and maintained in 



