KINDS OF DISEASE. 43 



of its generation ; and on the nature of the exciting cause. 

 Some peculiar conditions there are^ under which, no matter 

 how trifling or insignificant the exciting cause may be, disease 

 will assume the mahgnant form; wliile under other and 

 more ordinary states, even though the exciting cause be 

 most powerful, no unhealthy action will result. The nature 

 of the exciting cause, however, may be such as to ensure a 

 malignant effect ; as in the case of farcy and glanders from 

 contagion, from concentrated animal efiluvia, from excessive 

 exertion, &c. 



The Progress of disease in the horse, whose vascular 

 system is one of great development, could not fail to be re- 

 markable for its rapidity. In man, the celerity with which 

 disease proves fatal, is owing to nervous excitement, or consti- 

 tutional irritation, but in horses it will proceed rapidly yet 

 run through the stages of inflammation, and extinguish life 

 at last, from sheer organic destruction. Inflammation of 

 the lungs has run on to a state verging on grangrene, and 

 destroyed the animal within twenty-four hours of the onset 

 of the attack. Diseases of the nervous structures, however, 

 though they are fewer and more rare in horses than in men, 

 are likewise less active in the brute creation. 



KINDS OF DISEASE. 



Diseases are distinguished in relation to their seat, their 

 influence, their intensity, and their duration. 



A local disease is one circumscribed in its situation and 

 effects, extending no farther than the part in which it is 

 seated. A general or constitutional disease disturbs the 

 system at large. Splints, spavins, curbs, windgalls and 

 other lamenesses — also slight or trifling injuries and irrita- 

 tions of all sorts — come under the head of local diseases : 

 while such disorders as amount to sickness — inflammations 

 of the lungs, bowels, brain, and other organs — form a class 

 of general or constitutional diseases^ inasmuch as their in- 

 fluence is felt through the entire system ; although, as far as 

 their scat alone is concerned, they may be local. The only 



