208 DISEASES or THE HEART. 



HYPERTROPHY. 



This is a term introduced from the French into medi- 

 cine, to signify what in numerous instances we in former 

 times expressed by the words over-growth, enlargement, &c. 

 It is meant to denote an exuberance of growth from ex- 

 cessive nutrition, causing an augmentation of natural or 

 normal substance and volume. It would appear that 

 almost any organ or tissue in the body may become hyper- 

 trophied or anormally augmented in volume and power, and 

 yet preserve its normal functions sufficiently performed 

 not to occasion any alteration in the animal economy ; of 

 which the spleen is a remarkable instance. It is only when 

 inconvenience is thereby produced that we look upon hyper- 

 trophy in the light of a disease. On the present occasion, 

 hypertrophy is used to denote an augmentation or thicken- 

 ing of the substance of the lie art ; in order for us to have 

 correct notions of which, we should understand what the 

 weight and dimensions of the heart are in the normal 

 condition of the organ. 



The mngnitude and weight of the heart in health will 

 vary with the size of the horse : it will usually be greater in 

 a large than in a small horse, and in an entire horse than in a 

 mare. In horses of ordinary size, its weight seems to vary 

 from about 71bs. to 91bs. ; in a state of hypertrophy it has 

 been known to weigh 131bs. I am not certain, but think it 

 possible, that bleeding may influence its weight. Eclipse's 

 heart is said to have weighed 141bs. : it must have been 

 hypertrophied. Something also will depend upon the quan- 

 tity of exertion the horse may have been accustomed to. 

 Hypertrophy occurs in one of three forms : 



1. Simple hypertrophy, or hypertrophy without dilata- 

 tion, consisting simply in thickening of the walls of the 

 heart, without any alteration in the dimensions of its cavity. 



2. Hypertrophy with dilatation, the most common 

 form, in which the walls are thickened and the cavity dilated. 



3. Hypertrophy with contraction, in which the walls 

 are thickened and the cavity diminished. 



