MOVEMENTS OF THE HEART. 187 



The locomotion of the heart takes place in the direction 

 of its axis, and is due to the sudden disteiition of the great 

 vessels at its base. These vessels are eminently elastic, and 

 as they receive the charge of blood from the ventricles, be- 

 come enlarged in every direction, and consequently project 

 the entire organ against the walls of the chest. This 

 movement is somewhat aided by the recoil of the ventricles 

 as they discharge their contents. The displacement of the 

 heart during its systole has long been observed in vivisec- 

 tions, and may be demonstrated in any of the mammals. 

 The most interesting observations on this point are those of 

 Chauveau and Faivre, which were made upon a monkey. 

 In this animal, in which the position of the heart is very 

 much the same as in the human subject, the locomotion of 

 the organ was fully established. 1 



Twisting of the Heart. The spiral course of the super- 

 ficial fibres would lead us to look for another phenomenon 

 accompanying its contraction, namely, twisting. If we 

 attentively watch the apex of the heart, especially when its 

 action has become a little retarded, there is a palpable twist- 

 ing of the point upon itself from left to right with the systole, 

 and an untwisting with the diastole. 



Hardening 'of the Heart. If the heart of a living ani- 

 mal be grasped by the hand, it will be observed that at each 

 systole it becomes hardened. The fact that it is composed 

 almost exclusively of fibres resembling very closely those of 

 the voluntary muscles, explains this phenomenon. Like any 

 other muscle, during contraction it is sensibly hardened. 



Shortening and Elongation of the Heart. The foregoing 

 phenomena are admitted by all writers on physiology, and 



1 Nouvelles Recherches experimentales sur les Mouvements et les Bruits nor- 

 maux du Cceur, envisages au point de vue de la Physiologic Medicale. Par A. 

 CHAUVEATJ et J. FAIVRE. Paris, 1856, p. 24. 



