A STUDY IN MORBID AND NORMAL 1' II Y S I O L O G Y. 81 



Heat Production. 

 Before Section. 



Fall of aiiiiiial temperature 0.72 = t. 



Q = W X t X sp. h. = 16.5 X 0.72 X 0.75 = 9.99 = heat lost from n serve. 



Ileat (lis.'iiijatcd in one hour 188.8G72 



Heat lost iu cue hour from reserve 9.99 



Total production of heai in one hour 178.8772 



After Section. 



1st Period — , 



Fall of animal temperature 2.6 = t. 



Q = W X t X sp. h. = 18.5 X 2.6 X 0.75 = .■?6.07 = heat lost from reserve. 

 Heat dissipated in one hour 99.(>()'8 



Heat lost in oue hour from reserve 30.075 



Hourly production of heat 63.593 

 2d Period— 

 No alteration of animal temperature. 

 Hourly dissipation and therefore production of heat 139.8289 



Summary. 



Hourly production of heat before section 178.R772 

 Hourly production of heat after section : 1st period 63.593 



2d period 139.8289 



In the first of the.se experiments the markedly increased Itcat dissipation stron<2^Iy 

 indicates a partial vaso-motor palsy produced by effused blood. It is therefore 

 possible that the diminished heat production had its origin in this cause and 

 not in any irritation of inhibitory nerve fibres. Experiment 61 is a much more 

 decisive one. In it, directly after the wound and at a time when there were very 

 marked symptoms of motor irritation, both heat production and heat dissipation 

 were enormously reduced. It will be remembered that in vaso-motor palsy, heat 

 dissipation is at first increased, so that the fiict that the heat dissipation fell from 

 188.8672 units per hour to 99.668 units per hour proves that there was no vaso- 

 motor palsy. Indeed it would seem that no conceivable vaso-motor condition 

 could account for the symptoms. The wound was a small one situated high up, 

 i. e. at a distance from the vaso-motor centre, and could not have caused vaso- 

 motor palsy. Those who hold the irritation theory and explain the increased 

 production of heat which is produced by section of the medulla where it joins 

 the pons, cannot invoke the same irritation to account for the extraordinarily 

 diminished heat production (from 178.8772 to 63.593 units) caused by the slight 

 wound at the position of section in the other cases. In Experiment 59, after 

 division of the medulla the heat production steadily increased for hours, so that 

 twenty-four hours after division of the medulla the hourly rate was nearly four 

 times what it was before section, although during the first hours of section it was 

 only twice as great as the norm. Mechanical irritation naturally subsides rapidly 

 in its effects, instead of increasing in this way. This is very plainly shown by the 

 experiment last recorded. At first, heat production was lessened about two-thirds 

 by the puncture, but in twenty-four hours it had increased almost to what it was 

 before secticm — so nearly, indeed, that the difference, amounting only to about one- 



11 May, ISSO. 



