TEMPERATURE COEFFICIENT OF THE ACTION OF 

 /3-RAYS UPON THE EGG OF NEREIS. 



By ALFRED C. REDFIELD and ELIZABETH M. BRIGHT. 



{From the Laboratory of Physiology, Harvard Medical School, Boston, and the 

 Marine Biological Laboratory , Woods Hole.) 



(Received for publication, November 4, 1918.) 



Lepper^ has shov^n that grafts of rat sarcoma radiated at 15°C. 

 show very little difference in their behavior from those radiated at 

 37°C., but that the latter grow rather more slowly and disappear 

 sooner than those which have been radiated in the cold. So far 

 as we are aware no one has determined the temperature coefficient 

 of the physiological processes, nor of the purely chemical reactions 

 produced by rays from radioactive substances. The velocity of 

 photochemical processes, to which these reactions are closely allied, 

 is known to be affected very slightly by the temperature at which the 

 processes occur. The great mass of physiological reactions shares a 

 high temperature coefficient (2 to 3 for a change of 10°C.) with gen- 

 eral, non-photochemical reactions. ^ Data on the temperature co- 

 efficient of photosensory stimulation in animals do not appear to have 

 been pubhshed. Dr. Selig Hecht has recently determined that the 

 temperature coefficient of the sensitization process in Mya is of the 

 order of that of a photochemical reaction (personally communicated 

 results of unpublished experiments). Brown and Heise,^ reviewing 

 the literature of this aspect of photosynthesis, conclude that this 

 important photophysiological process has a temperature coefficient 

 of the same order (1.1 to 1.2 for a change of 10°C.) as those of photo- 

 chemical reactions, although the investigators who secured the data 

 on which this conclusion is based had assigned higher values to this 



^Lepper, E. H., Arch. Middlesex Hospital, 1914, xxxiii, 77. ' 



^ Kanitz, A., Die Biochemie in Einzeldarstellungen; Temperature und Lebens- 

 vorgange, Berlin, 1915, pt. 1. 



3 Brown, W. H., and Heise, G. W., Philippine J. Sc, C, 1917, xii, 1. 



255 



