201 



On the Mechanism of Chemical Temperature Regulation. 

 By J. M. O'Connor. 



(Communicated by J. Barcroft, F.R.S. Received November 18, 1915.) 



(From the Physiological Department, University College, Dublin.) 



Although the conception that, under conditions favouring heat loss, the 

 warm-blooded animal endeavours to maintain its body temperature by 

 increasing the quantity of material oxidised dates back to Crawford and 

 Lavoisier, it received but little attention until examined by Liebermeister 

 (1, 2) in the sixties. Liebermeister 's experiments did not carry conviction 

 to his contemporaries, and even when confirmed by Sanders Ezn (3), and by 

 Rohrig and Zuntz (4), were not met with universal acceptance (5). Further 

 experiments by Pfliiger (6) and his pupils tended to put the matter beyond 

 doubt, and not alone the existence but the normal activity of such a 

 mechanism was finally established by Herzog Carl Theodor in a careful 

 and prolonged series of observations on a single animal. Voit(8), in whose 

 laboratory these last experiments were conducted, gives an account of the 

 early literature. Since then Rubner (9) especially has devoted attention to 

 this increased combustion, especially studying the manner in which it is 

 influenced by food, growth of fur, and the like. 



Though the chemical heat regulation, as Rubner names it, has from this 

 point of view been thoroughly investigated, the mechanism by which its 

 activity is excited has attracted but little attention. Liebermeister (2), it is 

 true, formulated clearly a theory, according to which the increased produc- 

 tion of C0 2 in a cold bath is proportional to the extent to which tbe skin 

 has been cooled below a certain normal point and since his time it has been 

 customary to attribute chemical heat regulation to a temperature reflex 

 from the skin to the muscles (for example, Rubner). The rapid onset of 

 chemical regulation on exposure to cold (Pembrey, 10) makes some such 

 peripheral mechanism probable, but the theory has never been experi- 

 mentally tested, and is not altogether without opposition. Some would 

 attribute chemical temperature regulation in part (11) or exclusively to a 

 cooling of the brain, a view which has received recent prominent support 

 from the experiments of Barbour (12, 13). 



This lack of adequate investigation is perhaps to some extent due to the 

 belief unnecessarily placed on the experiments of Rumpf (14) — for example, 

 Krehl (15) — that in the anaesthetised animal regulation is distorted beyond 

 recognition, thus considerably reducing the possibilities of experiment. 



VOL. lxxxix. — B. s 



