DISEASES OF THE HEART 467 



the open hand is placed over the region of the heart. Moreover, the area 

 of the dull sound commonly invoked by percussion is extended in proportion 

 as the heart is enlarged, and this is the case whether the enlargement arises 

 from hypertrophy or from dilatation, or both combined. There is, besides, 

 more or less palpitation, especially under circumstances of exertion and 

 excitement. 



The usual recommendations to avoid excitement and fatigue are given 

 when the disease is diagnosed, but as a matter of course, unless it is in 

 such a stage that the rest that would be necessary need only be temporary, 

 the animal is rendered perfectly useless, and might as well be destroyed. 

 In fact, this alternative appears to be the reasonable one in all cases in 

 which the disease is indicated by marked symptoms. For example, when 

 an animal affected with a large heart — whether it consists in simple hyper- 

 trophy or only dilatation,' or of the two conditions together — suffers from 

 increased respiration when at rest, and to a greater extent during exertion, 

 with the addition of staggering, attacks of vertigo, trembling, sometimes 

 convulsions, and frequently derangement of the digestive organs, leading to 

 loss of condition, emaciation, and anaemia, it may be concluded that the 

 chances of recovery are so remote that it is not worth while to attempt any 

 treatment. 



ATROPHY OF THE HEART 



This condition, which refers to a diminution in the size of the organ 

 owing to wasting of the muscular tissue and a general failure of its con- 

 tractile power, is much less common than the enlarged state, hypertrophy 

 and dilatation. The characteristic symptoms are those which would be 

 expected from the anatomical changes. The circulation becomes extremely 

 feeble, the pulse is small and weak, and general failure of the supply of 

 blood to the whole of the system leads to passive congestions in difierent 

 organs and rapid emaciation, which would terminate fatally if the end were 

 not anticipated, as it usually would be, by slaughtering the animal. 



FATTY DISEASE OF THE HEART 



Two perfectly distinct conditions are included in the term fatty disease 

 of the heart. One consists in mere infiltration of the fatty material among 

 the muscular fibres of the heart, which may be observed in animals when 

 overfed (fatty infiltration), and the other consists in the actual conversion 

 of the muscular structure into fat (fatty degeneration). In the former, the 

 cells in the connective tissue between the muscular fibres become filled 

 with fat, and there is an excessive deposit of fatty material outside the 



