Diseases of the Organs of Circulation. 199 



sounds due to the watery condition of the blood, and 

 functional derangement of the organ, occasioned by im- 

 proper feeding, &c, not in any way referable to disease. 

 When the blood receives its natural pabulum from a suffi- 

 ciently nutritious food, the disorder disappears. Palpi- 

 tation of indigestion, not always attended with the loud 

 sounds of anaemia, is due to similar causes, and disappears 

 when the digestion is improved. 



Rupture of the Heart occasionally takes place 

 during severe running, or exertion in drawing heavy loads 

 over unmade roads. The seat of the lesion varies : 

 sometimes it is the junction of the aorta with the left 

 ventricle, or the right auricle as it joins the ventricle. In 

 one instance we saw the first form in a draught-horse, 

 occasioned by a fall over a temporary bridge to a lower 

 level of some fifteen feet. 



Cyanosis, Blue Disease, is due to the admixture of the 

 blood of arteries and veins within the heart, owing to 

 the non-closure of the foramen ovale, an opening which 

 should not exist beyond foetal life. The animal is weak, 

 faint, and useless, and, if not humanely destroyed, usually 

 lives but a short period. The significant tokens of the 

 malady are the peculiar blue colour of the membranes, 

 with anaemic palpitations. When life is prolonged in 

 exceptional cases, it is due to a small opening only, 

 admitting of slow admixture of the blood. 



Carditis, Inflammation of the Heart, is not common 

 to the horse. While the or- 

 gan may suffer in small por- 

 tions by an extension of the 

 process from contiguous struc- 

 tures, that process does not 

 extend to the whole substance. 

 The organ being so essential 

 to life appears to be wonder- 

 fully exempt from such a seri- 

 ous state as inflammation. It 



is, however, Subject tO altera- The countenances expressive! 



tionsinform — organic changes 



in the muscular structure, as hypertrophy or enlargement, 



