THE HORSE IN SICKNESS AND DISEASE 325 



production. We are now about to learn that the system 

 may become vitiated or corrupted, and disease in that 

 manner be engendered in it. There are various ways in 

 which noxious matters may obtain introduction into the 

 system, some of which are palpable and open to demon- 

 stration ; while others elude our observation so far as to 

 become apparent only through their effects. The channels 

 through which they gain admission are the alimentary 

 canal, the air-passages, and the skin. 



An animal may eat that which is unwholesome, mingled 

 with his food, or he may drink water that is insalubrious ; 

 or he may, under some casual or incidental circumstance, 

 lick in and swallow, mixed with his saliva, matter of a 

 contaminating or morbific nature ; in either of which ways 

 he may lay the foundation of disease in his system. 



Anssmia also may give lise to disease, either from the 

 insufficiency of the quantity of the blood for the purposes 

 of the animal economy, or from the thinness or poorness 

 of its quality. It is too prevailing a practice in the 

 regimen of the stable to keep horses "short of water," 

 under the impression that much fluid is injurious — a notion 

 that probably originated in the very proper custom of 

 giving water very sparingly at the time the animal is 

 required to exert himself. Hunters and racers are not 

 allowed any, or but very little indeed, on the morning of 

 the day they are to go to work. This, however, furnishes 

 no good reason why the animal is to be debarred from 

 quenching his thirst after his work is performed. 



SANGUINEOUS AND SEROUS CONGESTION. 



Sanguineous and serous congestion may exist in com- 

 bination. When a horse's legs fill from standing in the 

 stable (which they do from serous infiltration into the cells 

 of the cellular membrane), the tumour is not the result 

 of inflammation, but of sanguineous and serous congestion, 

 in consequence of standing long without exercise. Blood 

 accumulates in these parts remote from the heart. The 

 seriferous vessels especially suffer from distension ; and the 

 easiest mode in which they can relieve themselves is to 

 suffer the fluid to exude through their exhalant termina- 

 tions. A similar disposition of parts may pervade the 

 whole limb, as well as any cavit}^ organ, or part of the 



