IRRADIATION OF LIVING PROTOPLASM 639 



"P/W Konstant") was used as an index of permeability. The ray 

 effect on this constant over a period of time undulates, but the immediate 

 result is an increased "permeability" of lymphocytes and a decreased 

 "permeability" of tumor cells. 



Several applications of chemical methods of permeability determina- 

 tion remain to be considered. Kroetz (205) compared the rate of dif- 

 fusion of chloride across normal frog skin with that across skin exposed 

 to 10 to 30 H.E.D. In eight experiments, the average amount of A^/100 

 AgNOs required to precipitate the chlorides that had crossed the mem- 

 brane was 1.985 cc. for skin that had received 30 H.E.D. , while the control 

 value was 0.875 cc. Thus, in this series, irradiation caused a 198 per cent 

 increase in penetration. Kovdcs (198, 199), using 4 H.E.D. in a frog- 

 skin preparation, could detect no increase in the rate of diffusion of 

 hemoglobin. 



Magath (248, 250), Magath and Kolomyetz (251), and Jalin (175) 

 interpret data obtained with whole tissues as evidence for an increase 

 of permeability in cell membranes upon roentgen irradiation. Earlier, 

 Magath used the rate of swelling of normal and tumor tissue immersed 

 in acidic buffer solutions as a measure of permeability. He gave normal 

 and cancerous rabbits 5 to 6 H.E.D. The hver tissue of the normal 

 irradiated animal swelled twice as fast as that of the control normal. 

 Carcinoma tissue, however, showed a 20 per cent decrease in the rate 

 of swelling when irradiated. Previous immersion in CaCl2 reversed both 

 of these effects. The 1930 experiments, using phosphate production as 

 a measure of permeabiHty, gave identical relationships, although rat tissue 

 was used, and a dose of 300X. Jalin (175) found doses of 1 H to acceler- 

 ate the exosmosis of KI injected into rabbit muscle. 



The most direct evidence for the permeability-increasing efTect of 

 roentgen rays comes from experiments on erythrocytes. Biologically, 

 one of the most valuable of all the papers we shall consider is that of 

 Lehmann and Wels (215) who, unfortunately, did not define their ray 

 dose, but gave only tube voltage and amperage. After long irradiation, 

 beef erythrocytes in dextrose were centrifuged off, and the exosmosed 

 chloride determined in the solution. Irradiation caused an increase in 

 the amount of diffusion of this ion from the cells. By the use of the 

 hematocrit under the same conditions, they demonstrated that cell 

 volume diminished more rapidly after irradiation than normally, further 

 evidence of accelerated exosmosis. They also determined the total 

 electrolyte diffusion by electrical-conductance measurements, and by 

 comparing their results with the chloride determinations were able to 

 show that both NaCl and KCl diffused out. Finally, they measured the 

 rate of volume increase upon prolonged immersion of the cells in isotonic 

 NaCl; in one experiment, the average increase in the volume of the irra- 

 diated cells in 43 hr. was 49 per cent, the control value being 44.5 per cent. 



