THE STANDARD METABOLISM OF THE ORGANISM 59 



information in such a form that it can be compared with the standard 

 metabolism does not appear to be available. 



The metabolism corresponding to the respiratory movements has 

 been determined by Speck [1892] for man as 8 to lOc.c. of oxygen per 

 litre of air respired, but to his result a correction must be applied 

 (Zuntz and Hagemann) reducing it to 6 c.c. per litre. Loewy [1899] 

 found about 5 c.c. of oxygen per litre ventilation, Bornstein and v. 

 Gartzen [1905] 27 cal. = 5-6 c.c. of oxygen, and Zuntz and Hagemann 

 for the horse about 3-5 c.c. of oxygen per litre ventilation. As the 

 ventilation of a man at rest is something like 7 litres per minute, 

 about 40 c.c. of oxygen or 1 5 per cent, of the total exchange during 

 complete rest should be required for the mechanical function of res- 

 piration. Small variations in ventilation which occur often enough 

 even during rest may have a noticeable effect upon the standard 

 metabolism as measured, and it is obvious that the abolition of the 

 respiratory movements brought about by curari must appreciably 

 reduce the metabolism. 



The aggregate influence of the functional activities in the resting 

 body amounts according to the above to at least 25 per cent, of the 

 total standard metabolism. The true basal metabolism is therefore at 

 most 75 per cent, of the standard. It may be and probably usually 

 is still lower. The reason for drawing a sharp distinction between 

 basal and standard metabolism is therefore apparent. 



According to the recent work of Mansfeld and his collaborators 

 [1915] the tone of skeletal muscles is brought about by sympathetic 

 innervation and not directly as hitherto assumed. The tone is there- 

 fore not abolished by curari except in very large doses, and there can 

 be little doubt that in the standard conditions as at present defined the 

 muscular tone enters as a variable factor of considerable importance. 

 A detailed study of the effect of muscular tone upon metabolism is 

 certainly one of the chief desiderata in the physiology of the respira- 

 tory exchange. 



The constancy of the standard metabolism has been studied experi- 

 mentally several times. On man it has been found that the standard 

 metabolism is a constant quantity practically the same during sleep 

 and when the subject is awake and remaining absolutely quiet 1 (Loewy 



1 This statement has recently been controverted by Benedict [1915] who maintains 

 that the metabolism during deep sleep is lower (in the case of a man fasting for thirty -one 

 days by 13 per cent, on an average) than when the subject is awake but quiet. It would 

 seem rather probable that differences in the relaxation of muscular tone during sleep might 

 account for the differences recorded, 



