4 CORA SENNER WINKIN 



* 



effect of compression of the abdominal aorta. Konow and Stenbeck 

 (24) and Landergren (25) more recently stressed the functional sur- 

 vival of the cord in the decapitated animal preparation. The residual 

 spinal blood pressure was analyzed by Pike (26) (1912) who showed 

 that afferent impulses, presumably from skeletal muscles, were re- 

 sponsible for it. His observation that a further fall occurs on paralysis 

 of skeletal muscles by curare has recently been confirmed by Langley, 

 1919 (27). 



A revival of interest in the central relations of the asphyxial picture, 

 particularly to the higher nervous levels, was in part achieved through 

 the reexamination of the problems of resuscitation of the organism by 

 Stewart, (28), (29), (30), (31), (32), (33) Pike and Guthrie. These 

 observations threw sharply into relief the dependence of resuscitation 

 on the medullary respiratory and vasoconstrictor mechanisms rather 

 than on other organs, which, whatever their importance, were found 

 neither as sensitive nor as susceptible as the medullary and higher 

 cells. The functional activity of the medulla was abolished 15 minutes 

 or more, and in its abeyance, no independent existence of the animal 

 could be reestablished. An analysis of the conditions of so-called 

 spinal shock was undertaken by Pike (34), (35), (26), who employed 

 the procedure of cerebral anemia, and the vascular response obtainable 

 from it, as a means of comparing the various functional levels of the 

 central nervous system. In this way the central relations, particularly 

 to the bulbar levels, of the vascular response in anemia were clearly 

 indicated. A further extension of this problem is found in the study 

 Of Yates (36), in which the response to anemia was used as a criterion 

 of the degree of recovery of the vascular system following spinal tran- 

 section. These studies bring out the importance of the maintenance 

 of medullary activity as the essential factor in the avoidance of a 

 shock effect and the relative incompetence of the spinal cord in the 

 initiation of significant adaptive responses. 



Consideration of the excitatory and depressing effects of the blood 

 gases has led toward a recognition of their importance in influencing 

 the behavior of the medullary cells. The literature of the subject is 

 reviewed by Bethe (37), Hill and Flack (38), Hasselbach (39). Pike, 

 Coombs and Hastings (40), (41) have pointed out the adaptive nature 

 of the nervous changes induced by a rapid lowering of CO 2 tension in 

 dyspneic blood, and have suggested that in thus acting in a direction 

 opposite to environmental change, the organism meets the conditions 

 by adjustment of physical equilibrium as prescribed by le Chatelier's 



