Twenty sixth meeting. 



Rockefeller Institute for Medical Research. December iS, igoy. 

 President Flexner in the chair. 



14 (270) 



The effect of light on cells in fluorescent solution after addition 

 of potassium cyanide. 



By ELIZABETH COOKE and LEO LOEB. 



[From the Laboratory of Experimental Pathology of the University 



of Pennsylvania^ 



Since potassium cyanide inhibits certain oxidative processes in 

 living matter such as respiration in plants and animals, the seg- 

 mentation of fertilized egg cells, etc., behaving in this regard like 

 an atmosphere of hydrogen, it might be expected that the destruc- 

 tive action of light upon cells suspended in fluorescent solutions, an 

 action that is in part at least one of oxidation, would be diminished 

 or obliterated by the addition of potassium cyanide to such solu- 

 tions. On the contrary, the addition of very small quantities of 

 potassium cyanide to sea water containing fluorescent substances 

 (eosin, methylene blue, neutral red and combinations of these) 

 causes a marked acceleration of the destructive action of visible 

 light rays upon star-fish eggs immersed in these solutions. The 

 chemical character of the fluorescent substances being different, it 

 is evident that the chemical character of the fluorescent substance 

 does not influence the action of potassium cyanide. But if star- 

 fish eggs in such solutions be deprived of oxygen, by substituting 

 for air an atmosphere of hydrogen, they no longer undergo deter- 

 ioration under the action of light and this result remains uninflu- 

 enced by the addition of potassium cyanide to the solution. It 

 asserts this accelerating action only if added to eggs in fluorescent 

 solutions exposed to light. If the cells were first immersed in a 

 solution of potassium cyanide in the dark and afterwards trans- 

 ferred to the fluorescent solution in the light, potassium cyanide 

 did not show any effect. Also control experiments in which 



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