40 CORA SENNER WINKIN 



tion. The rough average of the level of blood pressure maintained is 

 given for each period. The exact correspondence of the involvement 

 of the splanchnic system and the degree of functional activity within 

 the medullary centers is indeed striking, especially in view of the po- 

 tency of the splanchnic system in maintaining blood pressure. It 

 appears from this tabulation that the splanchnic system behaves ex- 

 actly as do the respiratory, skeletal and ocular responses. When the 

 skeletal responses dependent on the higher levels are in abeyance, the 

 vasomotor responses of the splanchnic system are also absent. At 

 this time, moreover, that is, during the depression between occlusions, 

 the heart rate shows no appreciable change. The level of blood pres- 

 sure maintained is that shown by Gouty (16), Mayer (14), Pike (26) 

 and Langley (27) to be that held as long as the spinal cord itself remains 

 intact. Additional evidence that the depression of functional activity 

 is due to a complete interruption of conduction in the spinal cord, and 

 not to so-called spinal shock, is brought out by the behavior of the 

 animal in passing through these various stages. The bearing of the 

 validity of the shock hypothesis for any conception of the functional 

 organization of the nervous system has been discussed by Pike (123). A 

 .shorter statement of this relation is found in Yates's paper (36) . 



Comparison of somatic and ocular responses with vascular responses 



Control of the animal's responses by various nervous levels Average level of blood pressure 



1. Normal intact animal: responds as a whole, pupils 



narrow, corneal reflex, respiration normal 120 mm. 



2. Head subjected to anemia: struggles responses 



under control of stimulated area (head) skeletal 

 ' convulsions, respiratory spasms, corneal reflex lost. 180-200 mm. 



3. Head functionally dead, animal spinal: responses 



under control of spinal cord only no corneal reflex, 

 pupils widely dilated. No spontaneous respira- 

 tion. No skeletal reflexes elicitable 50-70 mm. 



4. Recovery of head centers : gradual return of responses 



controlled by head area, pupils narrowing no cor- 

 neal reflex spontaneous respiration returns after 

 pressure has risen somewhat, but still sporadic. 

 Skeletal reflexes elicitable in part 70-90 mm. 



5. Recovery completed; animal responds as a whole. 



Pupils narrow, corneal reflex, respiration reestab- 

 lished; functions coordinately, skeletal reflexes 

 present 120 mm. 



When a significant lesion in the splanchnic system has been inflicted 

 by the section of these nerves just before entrance into the coeliac 



