1072 



PHYSIOLOGY 



confirmed independently by His, and the muscular bundle running 

 between these cavities has since been known as the bundle of His, or, 

 better, as the auriculo-ventricular bundle. This bundle, in the 

 human heart, is in close connection with the fibres of the interauricular 

 septum and with the tissue at the junction of the superior vena cava 

 with the right auricle (the sino-auricular node of Flack and Keith), 

 which, as we have seen, represents the sinus venosus of the primi- 

 tive heart. The bundle arises in the auriculo-ventricular node which 

 lies at the base of the auricular septum on the right side, below and 

 to the right of the coronary sinus. From this point the bundle runs 

 along the top of the inter ventricular septum just below its membranous 

 part, and then divides into the right and left septal divisions which 

 run down in each ventricle on the interventricular septum and pass 



FIG. 436. Fibres of Purkinje, from a strand of the A.V. bundle. (TAWARA.) 



into the papillary muscles arising from the septum (Fig. 435). From the 

 papillary muscles fine bands or delicate strands run to the ventricular 

 muscle near the apex of the ventricle. It is easy to determine the 

 course of the bundle in sections of the heart since the muscle fibres 

 composing it are of a more primitive character than the rest of the 

 cardiac musculature, and have indeed long been known and dis- 

 tinguished under the name of the * fibres of Purkinje ' (Fig. 436). It 

 is found that division of this bundle absolutely destroys functional 

 continuity between auricles and ventricles. 



The fibres of the auriculo-ventricular bundle may be destroyed 

 by disease. In such cases we get a series of phenomena known under 

 the name of Stokes-Adams' disease, the main characteristic of which 

 is the slow contractions of the ventricle, accompanied by a rapid 



