CARDIOVASCULAR CHANGES DURING CEREBRAL ANEMIA 39 



after complete exhaustion of the reserve of adrenalin in the blood. 

 The necessity for the presence of adrenalin or of some other product of 

 adrenal activity in the blood for the maintenance of vasomotor tone, as 

 asserted by Elliott, seems again confirmed. The failure of blood pres- 

 sure alone seems able to carry with it the failure of all the other functions. 



From the evidence, the relative degree of constriction of the vessel 

 walls seems, to a considerable extent, a function of the amount of some 

 adrenal product in the circulation. The loss of this product seems to 

 mean complete failure; blood pressure stays only a few millimeters above 

 base line when the available supply is low, but an increased liberation, 

 or possibly even a redistribution, may give any degree of tonic contrac- 

 tion of the vascular muscles, reaching to maximum constriction, the 

 entire reaction perhaps depending on conditions at the myo-neural 

 junction. 



III. RELATION OF THE SPLANCHNIC SYMPATHETIC SYSTEM TO THE 

 CENTRAL NERVOUS SYSTEM. The central relations of the sympathetic 

 system have been tenaciously disputed, and cannot be entered into at 

 length. On the one hand, there has been the view defending its rela- 

 tive independence from the cerebro-spinal axis, originally advanced by 

 Bichat (115), and supported extensively by Volkmann (116). Goltz 

 in his latest work with Ewald (117) subscribed to this view, in his asser- 

 tion that the sympathetic peripheral ganglia could maintain normal 

 vascular tone, and mediate reflexes quite independently of the central 

 nervous system. 



However, the theory that the nervous outflow is essentially dependent 

 for its activity on cells of central, and particularly bulbar origin, has 

 always enrolled some powerful supporters. Two of Goltz's contempo- 

 raries, Eckhard (118) and Mayer (119) have defended this conception. 

 Recently Gaskell (120) and Sherrington (121) and still later Ranson, 

 (122), also endorsed it. 



Two points in the evidence on cerebral anemia will briefly cover the 

 relation of the medullary cells to the peripheral response. First, the 

 comparison of the splanchnic response with the other peripheral re- 

 sponses, and particularly the skeletal responses as controlled by the 

 medullary or higher cells, under the different functional conditions of 

 the nervous levels in these experiments; second, the behavior of the blood 

 pressure responses under recovery from various spinal lesions. 



Comparison of splanchnic response with other peripheral responses. 

 The following table gives the various stages which can be distinctly 

 separated when different functional levels control the animal's reac- 



