136 CLINICAL VETERINARY MEDICINE AND SURGERY. 



gestion, but later inflammation occurs, producing new connective- 

 tissue growth and sclerotic changes. The capsule becomes thickened 

 in places, or covered with little fibrous tufts. 



The kidneys are affected in their turn by the stasis in the vena 

 cava, but at first, and for a certain time, only show congestive changes. 

 They are slightly larger and of deeper colour than usual ; but even at 

 this stage the microscope may show proliferation of the epithelium 

 lining the straight tubules. At a later period interstitial nephritis 

 here and there produces atrophy of the uriniferous tubules, and forma- 

 tion of tracts of fibrous tissue, contraction of which renders the surface 

 of the organ irregular and knobby. In sections of this "cardiac 

 kidney" the Malpighian tufts appear injected and slightly prominent. 

 At certain points the tissue is hardened, whitish in colour, and of 

 lardaceous appearance. 



A time arrives when the various organs, including the brain and 

 spinal cord, and all vascular tissues feel the effects of this distension of 

 the general venous system ; but dropsy, oedema, and inflammation of 

 the meninges, generalised hardening of extensive tracts of tissue and 

 skin lesions are final complications which only appear at a very late 

 period. Ascites, hydrothorax, and hydropericardium are usually too 

 little marked to be recognised during life. Changes in the blood, 

 such as diminution in red blood-corpuscles, and alteration of the 

 plasma, also belong to the group of later complications. They slowly 

 become more marked, and lead to cardiac cachexia. 



Whether chronic mitral endocarditis follow acute inflammation, or 

 appear as a primary condition, its onset is always insidious ; even 

 when the mitral valve is contracted and insufficient, no special dis- 

 turbance may exist to attract attention, provided the insufficiency is 

 compensated. 



This latent period terminates as soon as the lungs become en- 

 gorged. Then the patients rapidly lose breath at work, and show 

 symptoms which are usually referred to broken wind. Many fail to 

 come under the veterinary surgeon's notice until an advanced stage, 

 when the symptoms are already so numerous as immediately to suggest 

 heart disease. Moreover the animal's history is often sufficient to arouse 

 such suspicion. When examining an animal apparently in health, 

 but the history of which tells of weakness, diminished capacity for 

 work, sweating, rapid loss of breath after moderate exercise, lying 

 down immediately on returning to the stable, capricious appetite, or 

 total loss of appetite ; then, provided these symptoms have existed for a 

 certain time, one should suspect heart disease whatever the animal's age. 



