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Mr. J. M. O'Connor. 



metabolism at 39°. That at times the regulation is capable of maintaining 

 the temperature is shown by the experiment illustrated by fig. 5. 



A further point to be considered is the temperature to which the animals 

 chemically regulate. This is always below the normal body temperature 

 (30-39°). I have the impression that the smaller the animal the lower it is, 

 but neither the results nor the conditions are sufficiently uniform to justify 

 a conclusion on this point. 



The fact that the anaesthetised animal regulates for a temperature lower 

 than the normal may be due to a direct action on the central nervous system 

 not accessible to further analysis. It may, however, be capable of another 

 explanation. If we conceive the animal unable to regulate and surrounded 

 by certain fixed thermal conditions there will be only one body temperature 

 at which the animal will be in equilibrium, and towards this point it will 

 regulate. If the basal metabolism be lowered the animal will be in 

 equilibrium with the same outside conditions at a lower body temperature 

 and will, according to the hypothesis, now regulate for this lower point. We 

 know that as a matter of fact narcotics acting, for example, on isolated 

 organs (26) do produce a lowering of the metabolism ; and the fact that in 

 myxoedema and in starved rabbits (27) a low basal metabolism is associated 

 with a subnormal temperature lends support to the explanation suggested. 

 In fever, too, though the point has scarcely been adequately investigated, the 

 increase of temperature appears to be always accompanied by an increased 

 energy exchange (28). That alterations in the circulation could equally 

 affect the equilibrium point is clear. 



The experiments are in consistent agreement with the theory formulated. 

 As an analysis of the normal mechanism of temperature regulation they are 

 not without objection. The periods of observation were very short. It is, 

 of course, true that long periods are more convincing, but, apart from this, 

 Subnet (29) is inclined to question absolutely the value of observations for 

 short periods. Passing the fact that long observations on animals in uniform 

 anaesthesia are scarcely feasible, it must be observed the Eubner objections 

 are arbitrary. It may, of course, be also true that the anaesthesia completely 

 perverts the mechanism in normal activity. The fact that through anaesthesia 

 we are able to reveal aspects of the question otherwise inaccessible must 

 compensate us for this slight suspicion. 



Without endeavouring to extend too widely the application of the results, 

 it may be noted that they lend support to Hering's theory of temperature 

 perception, and, if we assume the sensation of cold to be proportional to the 

 amount of oxygen resulting from shivering, do not agree with the Fechner 

 law. 



