RESPIRATORY EXCHANGE IN DIFFERENT ANIMALS 145 



parisons than the fresh, it is far from ideal, as the varying amounts of 

 reserve material, skeletal and other inactive tissues, must influence the 

 results unduly. The best basis would probably be the nitrogen 

 present in active tissues (E. Voit's " OrganstickstofT "), but the deter- 

 mination of this would in many cases entail very considerable diffi- 

 culties and none have been made so far. Materials for a comprehensive 

 and valid comparison are therefore absolutely wanting. 



In the following table a series of determinations have been put 

 together which can be considered as having been made under standard 

 conditions at least as regards muscular movements and at a constant 



TABLE XLIII. STANDARD METABOLISM OF DIFFERENT ANIMALS PER UNIT WEIGHT 

 AND PER UNIT " SURFACE " MEASURED AT 20. 



1 The metabolism has been calculated from the O 2 absorption in most cases, i lit. 

 oxygen = 4*8 Cal. 



2 Bohr's determinations were made at 15 and 27. The interpolation to 20 is some- 

 what uncertain. 



3 Determinations were made of the energy content of fresh chrysalides and fresh 

 imagines and the average loss of energy per day computed from these. The values which 

 include the visible metamorphosis and the muscular movements accompanying it are 

 probably rather high. 



4 The temperature varied from 13 to 24-5. The figures are very uncertain therefore. 

 3 The respiratory exchange has been determined by Warburg, per 28 mg. N, and he 



states that one million eggs contain 8-5 mg. N. I have assumed, in accordance with 

 Meyerhof, that the eggs contain 3 per cent. N, and calculated the weight and the meta- 

 bolism per kg. by means of these figures. 



10 



