CARDIOVASCULAR CHANGES DURING CEREBRAL ANEMIA 15 



the anemic rise fell short of reaching the original level. The cat 

 recovered, however, and subsequently made up the 10 mm. difference 

 in an anemic rise obtained after the stellate ganglia had been excised. 

 The greater splanchnics may have been involved in this case. 



Group II. This comprised the remaining 7 cats of the series. In 

 all these animals a complete bilateral section of the splanchnic nerves 

 was done in the thorax between their branching from the sympathetic 

 chain and before their entry into the diaphragm. On cutting the 

 splanchnic nerves the initial, fall of pressure was great, averaging 80 

 mm. In four cats the effect of occlusion was well marked, the curves 

 differing from the normal only in a slight reduction of the anemic 

 increment of blood pressure, this being 70 mm. in three cases. 

 In these cases also pressure did not reach the level held prior to section. 



In the three remaining cats of the series a still greater depression 

 of the anemic response was obtained. Cat 20 gave a most complete 

 picture. The anemic rise reduplicated all the characteristics of the 

 normal response on a smaller scale. A vagus effect appeared promi- 

 nently. The maximum anemic increment of pressure in these experi- 

 ments was 40 mm. When pressure fell spontaneously after occlusion 

 it reached the identical level maintained after section of the splanchnics 

 prior to occlusion. Low section of the spinal cord at this time induced 

 a further fall of only 10 mm. Hg. In cat 22 the acclerators were also 

 removed, and an even greater depression of the anemic response was 

 obtained, the entire change of level on occlusion amounting to only 

 5 mm. 



Cat 21 was slightly anomalous but yet highly instructive. The 

 animal showed a great resistance to anemia, and it took some 15 minutes 

 before the respiratory and vasomotor responses fully faded out. At 

 first the Record clearly approximated that of cat 20, an initial rise of 

 30 mm. being shown. With the parsistence of the bulbar functions, 

 however, there was reproduced on a different scale, the wide oscilla- 

 tions procurable in all animals difficult to asphyxiate. At first the 

 vasomotor oscillations were slight and rather irregular, but they grad- 

 ually developed into large and rapid waves in which the greatest ex- 

 cursion of blood pressure was developed, amounting to a fluctuation of 

 60 mm. at the height of the response. The level of blood pressure 

 from which these oscillations developed was not raised, the whole 

 response being simply recorded within this maximum variation of 

 60 mm. This offers a striking contrast to the analogous records of 

 incomplete occlusion periods of similar length obtained in intact ani- 



