Removal of Portions of Spinal Cord. 181 

 82 (1829) 



The effect on blood pressure of removal of portions of the spinal 

 cord in the thoracic region. 



By R. J. BOWEN, HELEN C. COOMBS and F. H. PIKE. 



[From the Department of Physiology, Columbia 

 University, New York City.] 



The argument for the functional independence of the periph- 

 eral ganglia of the sympathetic nervous system has rested 

 largely on the experiments of Goltz, who removed portions of the 

 thoracic region of the spinal cord after previous transection. Two 

 conditions should be sharply distinguished here: (1) when the 

 transection of the spinal cord is in the lower cervical region above 

 the level of outflow of the sympathetic fibers from the thoracic 

 roots. This condition has been considered by Sherrington, 1 who 

 showed that the blood pressure fell markedly on actual destruction 

 of the spinal cord 300 days after the first transection. (2) When 

 the spinal cord is transected in the upper thoracic region, leaving 

 a functional connection of the medulla oblongata with the periph- 

 ery through a few rami communicantes of the sympathetic 

 system emerging with the roots of the upper thoracic nerves. 

 Miss Yates 2 showed that systemic blood pressure fell on paralysis 

 of the medulla oblongata some days after the transection of the 

 spinal cord. It remains to determine the actual effect upon 

 systemic blood pressure of removal of portions of the spinal cord 

 below the level of transection after an interval of recovery. 



Cats were used in our experiments. The spinal cord , was 

 transected under aseptic conditions at varying levels from the 

 second to the ninth thoracic, and the animal allowed to recover. 

 Some days afterward, the animal was again anesthetized and the 

 systemic blood pressure recorded from a cannula in one carotid 

 artery. A mercury manometer was used. In one cat, in which 

 the level of transection was just below the fifth thoracic root, the 

 mean level of blood pressure was 114 millimeters of mercury six 

 days after the transection. The blood pressure remained at 78 



1 "The Integrative Action of the Nervous System," 1906, pp. 241-243. 



2 American Jotirnal of Physiology, 192 1, lvii, 68. 



