A STUDY IN MOi;i!II) AND NORMAL J" 11 Y S I O L O (J Y. S5 



Ilcat Prod iirtioa. 

 Before Sectiox. 



No iletermiuation of reserve heat. 



Heat dissipatiou, = heat production 123.SG42 



After Section. 



Fall of animal temperature 0.9 = t. AV = 30. 



Q = W X t X i^P- li. = 30 X fl-9 X O.7.") = 20.2.") = le.'^sened amomit of reserved beat. 



ITeat (lissipaliiiM (j7.0(J2G 



Heat drav.ii from reserve 20.2."> 



Summary. 



Hourly itrodiiclion of heat 4G.S126 



Hourly prodiu-tion of heat before section 123.8fi42 

 Hourly production of heat after section 40.K12G 



Huuiij decrease in production of heal 77.051G 



In looking over the summary of this experiment it will l)c seen that, altliongh 

 there was section of the medulla at its junction Avith the pons, yet the liourly rate 

 of heat production was decreased from 123.8G42 units to 46.8126 units. This 

 extraordinary result is readily accounted for hy the state of tlie respiration. The 

 rate of the breathing was reduced to four or five acts per minute, and the intensely 

 cyanotic lips and mouth of the unconscious animal showed the lack of oxygen. 

 This experiment is of ftirthcr interest on account of the great and rapid rise of the 

 bodily temperature which followed the operation notwithstanding the diminished 

 heat production. It affords a striking example of the fact that the temperature 

 register is no index of the amount of heat production. It is also important as 

 indicating that retention of heat follows vaso-motor spasm. Vaso-motor spasm, it 

 is well known, is one of the phenomena of aspliyxia, and must have been highly 

 developed when the first rise of temperature occurred. That excessive heat reten- 

 tion was the cause of the rise of temperature is very evident, and is also directly 

 proven. As the stimulation lasted and the relaxation of fatigue began to be 

 developed, the temperature began to fall, but even at this time heat dissipation was 

 at an hourly rate of 67.0626 instead of 123.8612. The difference of course had 

 much of its causation in the diminished heat production ; yet if the avenues of 

 escape had been open, the bodily temperature would have rapidly fallen to below 

 the normal point instead of remaining as it did over 3.5 degrees above normal. 

 How the results of this experiment could be explained by, or indeed made con- 

 cordant with, the irritation theory it is hard to understand. That the vaso-motor 

 as well as the respiratory system largely dominates heat production is abundantly 

 shown by my experiments npon the cord. After section of the cord there is of 

 course paralysis of the fibres which are cut when the medulla is separated from the 

 pons. This is however more than counterbalanced by the vaso-motor palsy, for 

 diminished heat production is always the result of cord section. 



The fact that the production of animal heat is influenced by some centres situated 

 in or above the pons Varolii, and also that it is in some degree independent of 



