THE DISEASES OF CATTLE. 277 



the region of the fore extremities ; this lameness may, perhaps, 

 be defined as subacute or chronic rheumatism, from the fact 

 that there is no increase in arterial nor respiratory actions ; but 

 the first thing we observe is, that the subject is laboring under 

 hypertrophy of the heart, perhaps carditis, or endo-carditis ; 

 and this is proof positive of the migratory character of rheu- 

 matism. 



But why should rheumatism attack the heart ? This is quite 

 an interesting question, and thus I answer it : The physiology 

 of the heart instructs us that its motions are governed by the 

 impression made upon the susceptible nervous tissues. Its re- 

 sponses are physiological when the whole system is unembar- 

 rassed ; it is the centre, not only of circulation, but of sym- 

 pathy, and responds to the impressions made upon the general 

 system ; so that if any disturbance shall occur in the animal 

 economy, in the form of fever, spasm, etc., or the animal be 

 affrighted, punished, or exposed to sudden variations in temper- 

 ature, the heart is one of the organs first deranged. Rheuma- 

 tism, therefore, being migratory, is apt, in travelling from tissue 

 to tissue, to locate on a deranged organ, especially when that 

 organ is one so easily excited as the heart. 



CAUSES OF RHEIBIATISM. 



The special cause of rheumatism is hereditary predisposition. 

 In certain families morbid tendencies are transmitted from pa- 

 rents to offspring, and display themselves in the development 

 of parental defect and deformity. There are, also, general ex- 

 citing causes, such as exposure after perspiring freely, damp 

 and cold stables ; errors in diet or in stable and l^arn manage- 

 ment, overwork, etc. 



Principal Symptoms of Chronic Rheumatism. — The subject 

 is generally observed to travel with a limited or stiffened gait, 

 when first taken out of the stable. He appears " stiffened up," 

 as the saying is, yet " limbers up" as he proceeds. This de- 

 pends, however, somewhat on the temperature of the atmos- 

 phere ; for the animal is nothing less than a walking barometer, 

 24 



