A STUDY IN MOR RTD AND NORMAL P 11 V S I I, O G Y. ()\ 



blood pressure was studied and found to be normal. In one experiment, which has 

 been previously reported (see Experiment 59), stimulation of the nerve had a very 

 decided effect upon the bodily temperature ; the result is however not contradic- 

 tory, for, at the autopsy, the section of the medulla was found to be partial ; and 

 it is probable that enough of the fibres remained intact to make the powerful 

 stimulation felt. 



The results of these experiments are seemingly different from those of similar 

 experiments made by 11. Heidenhain {Pjlihjers Archiv, Bd. iii. p. 510). That 

 observer states that in a number of instances he has found that irritation of a 

 sensitive nerve, after separation of the pons from the medulla, is followed by a fall 

 of temperature. On examining the record of the single detailed experiment, I 

 find, however, that the fall took place solely during the application of the galvanism 

 to the nerve, and amounted at such times only to from 0.05 to 0.1 of a degree C. 

 (0.09 to 0.18 F.). Indeed, througliout the experiment, the temperature really rose, 

 so that at the end it was decidedly higher during the periods of nerve excitement 

 than it was before the nerve had been irritated at all ; and at the close, when the 

 nerve was not stimulated, the bodily heat was 0.2 C. (0.36 F.) higher than at first. 

 This very slight fall of temperature, occurring during the period of stimulation, is 

 something very different from the profound fall, that we have been discussing, 

 which occurs some time after the stimulation. This slight, evanescent alteration of 

 temperature — which also occurred in Experiment 71 of my OAvn series between the 

 7th and 10th minute — is very probably due to alterations in the respiration or 

 circulation. The experiments of Heidenhain, therefore, corroborate rather than 

 contradict those Avhose records have just been given. 



In conclusion the experiments seem to establish the proposition tliat (jah-aniza- 

 tion of a sensitive nerve produces a fall of the hodily temperature hy acllny upon some 

 nervous centre situated either in or ahove the pons. 



The existence of some centre in or above the pons directly or indirectly 

 controlling heat production having been established, attention naturally directs 

 itself towards the discovery of the scat of that centre. Mechanical destruction of 

 the pons being evidently not practicable Avithout involving other vital portions of 

 the brain, I have tried to accomplish the result by means of caustic injections. 

 The experiments performed are as follows: — 



Experiment 72. 



A dog. 



