A STUDY IN M O R r. I D AND NORMAL P IT V S T O I, G Y 



59 



The amount of the arterial pressure was, linwcvcr, sufficient to prove the integrity 

 of the vaso-motor system, for if the vessels had all been dilated, the mercury in tiie 

 tube of the manometer could certainly not have stood wiiere it did. Whenever 

 asphyxia is produced in the normal animal, an enormous rise of arterial pressure 

 results, chiefly from vaso-motor spasm caused by tlie excess of carbonic acid in the 

 blood. The great rise of pressure (from 120 to 205) which followed arrest of re- 

 spiration in Experiment 48 is positive proof of the section having been made above 

 the vaso-motor centre. The following experiment is confirmatory of the preceding 

 one. 



Experiment 49. 



A stout younar do? above uiediiun .size. 



EEM.\KKS. 



Brain opened with slight hemorrhage. 



Medulla rut. Absolute paralysis of motion and of sensation at once devilop'-d. 



Arterial pressure 120 ; on galvanizing the nerve the pressure fell at first but soon 

 rose to 185, no movements e.xeept in niuseles supplied by nerve were elicited. 



Dog put in a box at a temperature of 90'-'. 



Temperature of box 102^. 



Temperature of box 104. 



Temperature of bo.K 90. 



Temperature of box 88. 



Temperature of box 94. 



Temperature of box 84. 



Temperature of bo.x 82. 



Temperature of box 76. 



Temperature of box 72. 



Temperature of box (i4. 



Temperature of box (i4. 



Temperature of box 04. 



Next morning the dog was fonnd dead. 



Autopsy Medulla was nearly severed obliquely, where it mersred info the pons. 



In this case, though there was a primary fall of temperature, the fever, when 

 developed, was independent of the external heat, for whilst tlie latter was steadily 

 falling from 104° to 72°, the animal heat rose from 104° to 107°. In this ex- 

 periment ihe arterial pressure rose from 120 to 185, when a sensitive nerve was 

 galvanized, and the vaso-motor system was therefore intact. 



Upori dogs I have performed a number of other experiments similar to those 

 just detailed, with a like result, but in a half dozen or more trials upon rabbits I 

 have not once obtained a distinct permanent rise of temperature after section of the 

 upper medulla. As examples of these experiments the following are submitted : — 



