544 Dr. E. P. Cathcart and Mr. J. B. Leathes. * [June 22, 



was 311 milligrammes, this was raised to 386 milligrammes. This is less 

 than the output on the former occasion, but, as on that occasion, the figures 

 for each of the periods in the 24 hours are above the average and particularly 

 that for the period ending at 7 p.m., which included the greater part of the 

 exposure to cold. 



On May 19, the third day of the diet, the body weight was 705 kilo- 

 grammes ; on June 4 it had risen to 73'2 kilogrammes. 



The results of this experiment point to the inference that one of the factors 

 largely concerned with the production of uric acid in the body and its 

 appearance in the urine is the reaction of the body to loss of heat ; and that a 

 part, it may be a large part, of the endogenous uric acid is, so to speak, the 

 chemical expression for the intensity of this reaction ; further, that this 

 reaction involves some form of activity distinct from voluntary movements of 

 the skeletal muscles, since such voluntary movements have, on the contrary, 

 the effect of diminishing the output of uric acid, at any rate while they are 

 going on. 



At the same time we are not prepared to say that the activity for which 

 the chemical expression is the output of uric acid, has no other physiological 

 expression than heat production in response to increased loss of heat. That, 

 indeed, would not at all represent our view. For it is at any rate clear, from 

 this experiment taken by itself, that the reaction set up by exposure to cold 

 may last on for a considerable time after the exposure. A glance at the 

 column in Table II, in which the output of uric acid for each 24 hours 

 throughout the experiment is shown, makes it obvious that the interval of 

 three days that elapsed between each abnormal phase of the experiment was 

 not sufficient to allow a complete return of the rate of output to its value in 

 the days before the first exposure. 



The nature of the activity concerned in this reaction to cold, and certain 

 other points arising out of the data in Table II, will be entered into more 

 fully on another occasion. 



