CAKDIO-VASCTJLAR CHANGES DURING CEREBRAL ANEMIA 11 



3. Excision of the entire cardiac innervation. In three cats the sec- 

 t'on of both vagi and accelerators was undertaken without any previous 

 lesion. In two of them, section of the vagi was undertaken first, and 

 in both cases a rise of 20 mm. obtained. Subsequent section of the 

 stellates did not appreciably lower (by more than 5 mm.) the original 

 level. The order in which the section of the cardiac nerves is carried 

 out is, therefore, significant for the general level of pressure, and is 

 again in agreement with Miss Wickwire's findings. Several successive 

 curves were obtained from cat 5. The anemic increment was in these 

 cases somewhat reduced, increments of 80 to 100 mm. being obtained 

 after elimination of all the extrinsic cardiac nerves. When all cardiac 

 nerves were sectioned, the curve tended to be smooth, the initial acute 

 rise not being at all delayed. No change in the occlusion time was 

 noted. 



Recovery from occlusion after excision of one or both sets of the 

 extrinsic cardiac nerves was uniformly o.btained. The time interval 

 of recovery was in no way different from that in normal animals. 



In additional cats to be mentioned later, excision of the extrinsic 

 innervation was preceded by a low section in the sympathetic chain. 

 One animal gave an even higher anemic increment (125 mm. Hg.) 

 than is usually obtained after section of the cardiac nerves alone. 



In all the curves of reaction to anemia from animals with denervated 

 hearts, pressure was not uniformly maintained at the maximal level. 

 In two cases the pressure dropped immediately; in the rest (4 cases) 

 a plateau was maintained. 



4- Effect of the cardiac innervation on the anemic rise. Neither lesion 

 of the cardiac innervation, as a whole, nor of the vagi, nor of the stellate 

 ganglia separately, greatly affects the blood pressure response. Its 

 duration seems to be fairly constant for the given individual tested. 

 Excision of the entire cardiac innervation may reduce the anemic merer 

 ment in some cases, but the reduction when it occurs does not seem to 

 be considerable. 



However, the cardiac nerves seem to have considerable influence on 

 the level of blood pressure in the more detailed relations of the anemic 

 rise, especially in the early part of the reaction. From the results 

 of the section of the accelerators, particularly the abruptness with which 

 an intense rise appears immediately on occlusion of the head arteries, 

 it seems that the conception of the action of the accelerators must be 

 extended. Marey asserted in 1881 that with the vagus intact no very 

 great rise of pressure can be obtained. Indeed, as long as the vagi are 



