VI. Contributions to the physiology and pathology of the mammalian heart

Abstract

The observations upon which the following communication is based were made upon the Mammalian heart under conditions as nearly approaching the normal as we were able to make compatible with the employment of accurate recording methods. Our object throughout has been to study the mechanism of the Mammalian heart in situ by methods of research which would give to the subject a degree of exactness as closely as possible approximating to that of the work of Kronecker, Coats, Gaskell, Heidenhain, &c., on the excised hearts of cold-blooded animals, and of N. Martin and his school on the excised Mammalian heart. It need hardly be said that the mode of action of the heart of warm-blooded Mammals is a much more difficult subject of study than that of the heart of a Frog or Tortoise. The hearts of these latter animals are simpler in structure, to begin with, than those of a Rabbit, Cat, or Dog, and if the subject be further simplified by excising the organ and keeping thereby under control the nerve impulses which reach it, as well as the pressure and composition of the blood which enters and leaves its cavities (supposing the heart to be supplied with blood at all), some of the difficulties are greatly reduced. In the excised surviving heart of cold-blooded animals we have a piece of machinery whose action and attributes can be studied with a degree of accuracy and ease which corresponds with its comparative simplicity.