MUSCLE TONUS AND CO2 OUTPUT 55 



SUMMARY 



The action of light on the eyes of an animal (like the grass- 

 hopper), affecting the tonus of muscles, is associated with a 

 decrease in the rate of CO2 output of the organism. A similar 

 decrease in rate of CO2 output is also found in decapitated indi- 

 viduals. 



LITERATURE CITED 



1 MoLESCHOTT 1855 Wien. med. Woch. no. 43 (from Krogh '16, Respiratory 



exchange of animals and man. Longmans, Green & Co.). 



2 LoEB 1888 Pfliiger's Arch., Bd. 42, S. 393. 



3 EwALD 1892 Journ. of Physiol., vol. 13, p. 847. 



4 Holmes 1916 Studies in animal behavior. Boston. 



5 Garrey 1918 Journ. Gen. Physiol., vol. 1, p. 101. 



6 LoEB 1918 Forced movements, tropisms and animals conduct. Phila- 



delphia: J. B. Lippincott Co. 



7 Jacobs 1920 American Naturalist, vol. 54, p. 91. 



8 Bethe 1897 Pfluger's Arch., Bd. 68, S. 494. 



9 EwiNG 1904 Kansas Univ. Sc. Bull., vol. 2, no. 11, p. 305. 

 10 Lyon 1900 American Jour. Physiol., vol. 3, p. 86. 



THE JOURNAL OF EXPERIMENTAL ZOOLOGY, VOL. 35, NO. 1 



