24 CORA SENNER WINKIN 



sequent fall occurs under further manipulations, lies between 35 to 50 

 mm., the residual pressure maintained by the spinal cord alone. 



Group III. Retention of an anemic effect. The midthoracic region 

 is apparently not critical for vasomotor responses in all animals. In 

 cat 34 section at the 8th thoracic gave a loss of only 30 mm. Hg. and 

 an anemic increment of 68 mm. Hg. was obtained. The relatively 

 slight loss of pressure following section at T 7 in cat 39 above mentioned 

 also shows that in some animals the higher levels of the cord are of 

 great importance. 



However, the most significant indication of participation of the upper 

 levels of the cord in conveying fibers significant for the vasomotor 

 response was obtained in four additional animals. A strikingly com- 

 plete anemic rise was obtained from cat 30, in which the cord had been 

 sectioned as high as T 5 (fig. 3) . The anemic increment here was 54 

 mm. In cat 38 a well-maintained response of 44 mm. was obtained on 

 occlusion after section at T 6. In cat 31 a rise of the same magnitude 

 (40 mm.) was obtained after section at T 2. The level maintained 

 after section at T 2 prior to occlusion was 65 mm. Hg. above base 

 line and did not reach the level of 50 mm. until after occlusion. An 

 interesting record of the potency of the higher levels in certain indi- 

 viduals for both the maintenance of blood pressure and its variation is 

 best given in the following protocol cat 40. 



Condensed protocol, cat 40 (pressure here given in level above base line) April 22, 1918 



Tracheotomy, blood pressure, cannula, laminectomy, head arteries prepared 



for ligation. 



2:30 Control blood pressure 130 mm. Hg. 



2:35 Section of cord at T 8 



2:40 Level of blood pressure 118 mm. Hg. 



2:45 Section of cord at T 6 



2:47 Level of blood pressure 90 mm. Hg., total depression of pressure 40 mm. 



2:48 Corneal reflex 



Occlusion. Sharp rise of pressure to 114 mm. drop to 90 mm. Hg., great 

 vagus effect, rise again to 130 mm.: anemic increment 40 mm. 



2:51 Pressure released before spontaneous fall began, gasps immediately return, 

 fall to 80 mm. 



2:57 Respiration reestablished, section of cord at T 5 



2:58 Level of blood pressure 70 mm. Hg., total depression of pressure 60 mm. 



2:59 Corneal reflex, occlusion: -incomplete 



3:01 Further manipulation of clamps, immediate rise of pressure to 114 mm., 

 anemic increment 44 mm. 



3:04 Released before spontaneous fall, pressure drops to 50 mm. Hg., but imme- 

 diately begins again to recover 



