J. W. Capstick and T. B. Wood 261 



his bladder. Its shape is quite characteristic of urination. The warm 

 urine falling on the floor of the calorimeter causes a rapid rise in the 

 temperature of the outlet water followed by an etjually rapid fall as the 

 urine cools. This fall is checked by the rise of metabolism due to the 

 movement of the hog, which does not show itself so quickly as the rise 

 due to the warm urine. 



The peak at 1.15 a.m. was caused by a small movement of the hog. 



It is obvious that it is impossible to take any measurements of the 

 resting metabolism in the day-time or the earlier part of the night. 

 When the hog has gone to sleep it takes many hours for the metabolism 

 to sink to its correct resting value uncomplicated by the effects of 

 muscular activity. The fall during the night is not entirely due to 

 recovery from the day's activity. It is prolonged by the lag in the galva- 

 nometer readings arising from the heat capacity of the calorimeter. 

 This heat capacity, whilst not altering the total area of a hump, 

 reduces its height and sjireads it over a greater time. Further it is 

 known that the body temperature in man falls to a minimum in the early 

 hours of the morning and it is possible that there is a similar fall in swine 

 which would in itself cause a fall in the heat evolution during the night. 



The final conclusion from the study of these galvanometer curves is 

 that it is only on rare occasions that observations of the resting meta- 

 bolism free from the effect of muscular activity can be made at any 

 other time than in the early hours of the morning. 



The galvanometer records have been taken continuously through the 

 whole period of the fast. The readings of the various thermometers, etc. 

 needed for calculating the heat evolution have in general not been 

 taken during the day. Through the night they have been taken at 

 hourly or occasionally at half-hourly intervals, unless the curve showed 

 that the readings would be useless. At the end of each day the curve 

 and the record of the readings were carefully studied to find the time 

 or times at which the metabolism most nearly approached a steady 

 minimum. It is not possible to be biased in making the selection for 

 the calculation is so long and involves so many readings that it is quite 

 impossible to foresee the result before the calculation is completed. 

 Most frequently only one point was selected from the day's records — 

 occasionally two or three — on a few occasions no point showed sufficient 

 steadiness. The metabolism was in a few cases calculated at points 

 within 24 hours of the hog's entering the calorimeter, but these early 

 readings have less weight than those taken later. The hog never really 

 settled down until the second night. 



