Destruction of Strophanthin. 



89 



The toxicity of strophanthin by the mouth can be varied at will 

 to a considerable degree for the cat. 



51 (307) 



On the nature of the socalled glycogenolytic fibers in the 

 greater splanchnic nerves. 



By J. J. R. MACLEOD. 



[From the Physiological Laboratory, Western Reserve University^ 



The hyperglycsemia which invariably results from interference 

 with pulmonic ventilation, produced either by constriction of the 

 air passages or by inadequacy of the respiratory movements, has 

 led to the question whether or not the hyperglycsemia following 

 stimulation of the great splanchnic nerves may not also be due to 

 an asphyxial condition induced locally in the liver. Such a local 

 asphyxia of the hepatic lobule might be the result of diminished 

 blood supply caused by constriction of the blood vessels in 

 Glisson's capsule, or by the diminution of portal blood supply 

 following constriction of the splanchnic vessels. 



The question, therefore, presents itself as to whether stimula- 

 tion of the great splanchnic nerve causes hyperglycogenolysis 

 because secretory nerve fibers influencing the production or activity 

 of the glycogenolytic ferment in the liver are contained therein, 

 or because of a local disturbance in the blood supply of the liver 

 following stimulation of vaso-constrictor fibers. 



In the following communication a preliminary report is offered 

 of several experiments devised to throw some light on these 

 problems. 



1. All the tissues running to the hilus of the liver except the 

 portal vein were cut between peripherally and centrally placed 

 ligatures. As much as possible of the outer coat of the portal 

 vein was also removed. By these three operations all the hepatic 

 nerves running from the cceliac plexus to the liver were severed. 

 Stimulation of the great splanchnic nerve was found to cause no 

 increase in the sugar content of the blood although the usual 

 marked vaso-constriction of the splanchnic vessels occurred. 



2. Clamping the portal vein for periods of about a minute at 



