SUCCESSION OF MOVEMENTS OF THE HEART. 



195 



the other passes into the ventricle. The bags are connected 

 with distinct tubes which pass one within the other, and are 

 connected by elastic tubing with the registering apparatus. 

 At each systole of the heart the bags in its cavities are com- 

 pressed, and produce corresponding movements of the levers, 

 which may be registered simultaneously. 



To register the impulse of the heart, an incision is made 

 over the point where the apex beat is felt, through the skin 



FIG. 2. 



Figure representing the " cardiographe" of Marey. "The instrument is composed of 

 two principal elements : A E, the register-ing apparatus and A S. the sphygmographic ap- 

 paratus, that is to say, which receives, transmits, and amplifies the movements which are to 

 be studied." The compression exerted upon the bag c, which is placed over the apex of the 

 heart between the intercostal muscles, is conducted by the tube fc, which is filled with air, to 

 the first lever. The compression exerted upon the bags o and , in the double sound, is con- 

 ducted by the tubes t o and t v to the two remaining levers. The movements of the levers are 

 registered simultaneously by the cylinders A E. (MAKEY, Sur la Circulation du Sang, 

 Paris, 1863, p. 54.) 



and external intercostal muscle. A little bag, stretched over 

 two metallic buttons separated by a central rod, is then care- 

 fully secured in the cavity thus formed, and connected by an 



