RATE OF RECOVERY FROM THE ACTION OF FLUORITE 



RAYS. 



By W. T. BOVIE and D. M. HUGHES. 



{From the Cancer Commission of Harvard University, Boston.) 



(Received for publication, October 15, 1918.) 



This paper is a report of some experiments upon the rate of recovery 

 of Paramecium caudatum from the cytolytic action of fluorite rays. 

 The organisms were exposed to the radiation emitted through the 

 fluorite window of the hydrogen discharge tube described in pre- 

 vious communications.^'^ The intensity of the radiation was such 

 that an exposure of 8 seconds caused cytolysis in 57 per cent of the 

 exposed organisms. In order to study the rate of recovery from 

 the action of the rays, the entire 8 seconds of radiation was not 

 given in one exposure, but in two portions of 4 seconds each, with a 

 longer or shorter interval of time intervening between the two ex- 

 posures. The relation between the length of this interval of time 

 and the percentage of organisms cytolized was observed. 



The organisms used were from a pedigreed race of Paramecium 

 caudatum, cultured in drops of nutrient infusion on concave micro- 

 scope slides. A single organism was placed in a small drop (meas- 

 ured to uniform size) and exposed to fluorite radiation on a special 

 microscope slide provided with a fluorite window. The rays passed 

 through the fluorite window of the microscope slide from below. 

 After the exposure the small drop containing the organism was 

 flooded with from one to two drops of infusion and the organism was 

 transferred to a new concave slide and placed in a damp chamber for 

 observation. The following day, the cytolized organisms were dis- 

 integrated, while the organisms which survived were active and 



^ Bovie, W. T., The action of Schumann rays on living organisms, Bot. Gaz., 

 1916, Ixi, 1. 



2 Hughes, D. M., and Bovie, W. T., The efifects of fluorite ultra-violet light 

 on the rate of division of Porowecww caudatum, J. Med. Research, 1918, xxxix, 

 233. 



323 . 



