THE REGULATION OF THE CIRCULATION 263 



statement may be made that they come from certain 

 ganglia upon the dorsal wall of the thorax. The cells 



FIG. 57. A diagrammatic representation of the heart's nervous 

 connections, (x-x-x) is the vagus, descending from the medulla to 

 the abdomen and giving inhibitory fibers to the heart; (g-g-g-g) are 

 ganglia of the so-called "sympathetic" chain, supplying accelerators to 

 the heart. Only the nerves in the left half of the body are illustrated. 



in these ganglia are under the influence of nerve fibers 

 from the neighboring spinal cord. A skilled operator 

 can pick up slender strands between the ganglia and 



