A HISTORY OF METABOLISM 43 



and the smaller animals present a relatively larger area to the environ- 

 mental air, they experience a substantial cooling effect, and it becomes 

 necessary that the sources of heat production operate more energetically 

 and that the respiration increases. 



14. Awakening marmots consume oxygen in very largely increased 

 quantity. 



17. Reptiles consume much less oxygen per unit of body weight than 

 do warm-blooded animals, but do not differ from them in the relative 

 quantities of oxygen and carbon dioxid. 



18. Frogs without lungs respire just as well as frogs with lungs. 



19. Frogs and earthworms show nearly the same metabolism per 

 kilogram of body substances. 



20. The respiration of insects, such as beetles and silkworms, is very 

 much more active than that of reptiles. For equal body weights they 

 consume as much oxygen as mammals, and a proportionately large amount 

 of nourishment. We are comparing insects with animals two to ten 

 thousand times heavier than they. 



A thermometer placed in the midst of a mass of active beetles inclosed 

 in a sack showed a temperature of two degrees higher than the sur- 

 rounding air. 



The results of the work on these lower forms of life may be thus 

 summarized : 



Weight Oxygen per 



gm. R. Q. kg. per hr. Temp. 



37 Beetles 37. 0.82 0.962 



18 Silkworms . . 42.5 0.79 0.840 



25 Chrysalides.. 21. 0.64 0.240 



- Earthworms. 112. 0.78 0.101 



2 Frogs 127.5 0.75 0.105 19 



21. Animals of different species respire just the same in air con- 

 taining two to three times the usual quantity of oxygen, and do not per- 

 ceive the difference in oxygen content. (The air contained 72.6 per cent 

 of oxygen.) 



22. If hydrogen replaces nitrogen of atmospheric air there is very 

 little difference in the respiration process. (The air contained 77 per t 

 cent of hydrogen and 21.9 per cent of oxygen.) 



There were 104 experiments in all. 



Regnault and Reiset exemplify their natural instincts of friendship 

 and courtesy when they write that experiment 26, in which they varnished 

 a dog with gelatin, was done at the suggestion of "cet habile physiologiste' 

 Magendie," and that M. Bernard "dont 1'habilite est bien connue de tons 

 les physiologistes" had extirpated the lungs of the frogs about half an 

 hour before placing them in their apparatus. 



