RESPIRATORY METABOLISM OF PLANARIA AGILIS. 2IQ 



SUMMARY. 



1. Oxygen concentration becomes a limiting factor in the rate 

 of oxygen consumption by Planaria agilis at about one third 

 air saturation of water at 20 C. 



2. Life in low oxygen concentrations results in an accelerated 

 respiratory metabolism varying from two to eighty-five per cent, 

 when the animals are returned to air. This increase is not 

 proportional to, nor directly dependent upon, the previous length 

 of time which the animals have lived in what practically amounts 

 to an absence of oxygen. Some slight evidence was obtained 

 which indicated that repeated subjection of Planaria agilis to 

 low oxygen concentration may result in a small decrease of the 

 acceleration of oxygen consumption when returned to aerated 

 water after living in very low oxygen concentration. 



3. The percentage acceleration of oxygen consumption referred 

 to under 2 is more marked in starved than in fed animals. 



4. The rate of carbon dioxide elimination continues at prac- 

 tically the same rate in hydrogen as in air, until loss of irritability 

 and muscular tone begins. The loss of irritability in Planaria 

 agilis is therefore more closely correlated to change in rate of 

 CO 2 production than to consumption of free oxygen if in fact 

 it is correlated closely to either one. 



5. The effect of KNC in inhibiting the oxidations in Planaria 

 is not identical with the effects due to the absence of free oxygen. 



BIBLIOGRAPHY. 

 Allen, G. D. 



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 Henze, M. 



'10 Ueber den Einfluss des Sauerstoffdrucks auf den Gaswechsel einiger Meere- 



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