HYPEETEOPHY OF THE HEAET. 365 



HYPEETEOPHY OF THE HEAET. 



Increase in the size of the heart and in the thickness of 

 the walls of some of its cavities, has been long since observed 

 by veterinarians. Eecorded cases have not been always satis- 

 factorily described, and the first author who has furnished us 

 with a concise history of the lesion is M. U. Leblanc. By 

 careful comparison of hearts affected with different forms of 

 hypertrophy and healthy hearts, he finds that there are three 

 distinct varieties of the lesion. The first is that in which 

 the walls of one or more cavities are thickened without change 

 in the capacity of the cavities: this is the simple hypertrophy. 

 In the second, the walls of one or more cavities of the heart 

 are hypertrophied, and the cavities enlarged : this is eccentric 

 hypertrophy, which Corvisart has called active aneurism of 

 the heart, in the human subject In the third form, hyper- 

 trophy of the walls and diminution in size of the cavities co- 

 exist : this is the concentric hypertrophy. Hypertrophy of 

 the heart is usually associated with other diseases, and espe- 

 cially with pulmonary lesions. 



The origin of this disease depends on some obstruction to 

 the circulation, or cause which induces increased activity of 

 the heart. Leblanc believes that chronic inflammatory dis- 

 ease of the serous membranes, covering or lining the heart, 

 may induce hypertrophy, and he notices also the obstructions 

 to the flow of blood by constriction of vessels and of the aper- 

 tures between the different cavities of the heart. 



Symptoms. In simple hypertrophy the action of the 

 heart is stronger than usual, though the impulse is not so 

 sharp, and is felt lower than usual. This condition is found 

 to persist. The sounds of the heart are more intense, though 

 indistinct, provided that the cavities are not diminished in 

 size. A metallic bruit is often heard most distinctly near the 



