J. W. Capstick and T. B. Wood 



265 



Before the measurements can be used for finding the critical tem- 

 perature they must be corrected to a standard weight and a standard age. 



The standard weight chosen is 300 lbs., as this lies almost half-way 

 between the extremes of weight. In making the correction it is assumed 

 that the metabolism is proportional to the hog's surface area and that the 

 area is proportional to the two-thirds power of the weight. 



The basal metabolisms in the sixth column of Table II are calculated 

 from those in the fifth column on these assumptions. 



In order to provide data for a possible age correction observations of 

 the basal metabolism were made in the neighbourhood of 13° C. on 

 December 4, February 25 and March 22. These three were at 13-3°, 

 13"6° and 12'8° respectively. The difference is not great, but as they 

 fall at a part of the range where the change of metabolism with tem- 

 perature is considerable they should be corrected to the same temperature 

 before they are used for finding the age correction. 



300 320 340 360 380 400 420 440 460 

 Age in daj'S 



Fig. 3. 



This correction requires a knowledge of what it was the object of the 

 experiments to find — namely, the relation between basal metabolism 

 and temj^erature — and it is somewhat illogical to make such a correction 

 at this stage. As however the correction is quite small it is not likely 

 that any appreciable error will be made by assuming for this purpose 

 that there is a linear relation connecting the metabolism and tempera- 

 ture between 10-3° and 20-4°. This gives a fall of -077 calories per Centi- 

 gi-ade degree, and using this value we have the corrected metabolisms 

 shown in the seventh column of Table II. The final curve of Fig. 4 

 shows that a linear relation is not far from the truth. 



Fig. 3 shows the result of plotting the basal metabolism at 13-3° 



