314 



PHYSIOLOGICAL REGULATIONS 



hours are greater or less than between successive quarter-hours 

 (table 36). Since no systematic diversity appears in the coeffi- 

 cients of difference with various time intervals, it may be concluded 

 that (a) constancy of these measurements is not increased in the 

 longer periods, and (b) inertia-like fluctuations (runs and gaps) 

 do not last longer than 0,25 hour. 



Extending the determinations of loss by vaporization to still 

 shorter times, Gasnier and Mayer ( '34, p. 186) estimated the losses 

 of body weight (latent heat losses) within successive periods whose 

 duration averaged about 0.01 hour. In these the variability was 

 very much greater. Although the method of measurement was 

 satisfactory in the absence of the rabbit, it is possible that the 



TABLE 37 



Bates of heat loss, Cal./kg. Jir., in dry air at 18° C. BabMts in diverse states. 

 Data of Gasnier and Mayer {'34) 



recoils of the animal upon the automatic balance used were suffi- 

 cient to create irregularities in apparent rate of loss, and I draw 

 no conclusions from the data. 



(2) Heat loads are established by means, such as ice baths, 

 similar to those in man. Stationary rates of loss during loading 

 may be as high as 33 Cal./kg. hr. (table 34). This, however, rep- 

 resents a smaller augmentation ratio than obtained in man, since 

 the rate of turnover is in rabbits several times that in man (for 

 equal body masses). Positive heat loads are established by inject- 

 ing dinitrophenol or methylene blue along with a narcotic. 



During recoveries from established loads (table 37), two paths 

 of heat loss may be compared. In extreme conditions, sensible 

 losses are almost as greatly modified as are latent losses. Possi- 

 bly there is a contrast here with man (table 35), where vaporization 

 plays a more predominant role. 



