INNERVATION OF HEART AND BLOOD-VESSELS 571 



blood-vessels has returned. The spinal eord has 

 taken up the vasomotor function of the bulb. 

 Evidently the spinal cord contains vasomotor 

 cells, which ordinarily are subsidiary to those of 

 the bulb, but which, when separated from their 

 master cells, acquire the power of independent 

 action. 



Effect of Destruction of the Spinal Cord on the 

 Distribution of the Blood. Further evidence of 

 the vasomotor function of the spinal cord is 

 afforded by the following experiment. 



Expose the heart, avoiding unnecessary loss of 

 blood. Lay bare the upper part of the intestine 

 by an incision on the left side of the umbilical 

 vein, which lies in the median line. Suspend the 

 frog vertically. Note that the heart and the great 

 vessels are filled with blood. Note also the size 

 and number of the vessels in the walls of the 

 stomach and intestines. 



Bend the frog's head. Put the seeker into the 

 vertebral canal and pass it gently downwards to 

 destroy the spinal cord. The seeker will move 

 easily, if really in the canal. Look at the heart 

 and great arteries. 



The heart will soon be bloodless, though beating 

 regularly. Examine the vessels of the stomach 

 and intestine. They are distended. Evidently, 

 the contents of the heart and the great arteries 



