642 BIOLOGICAL EFFECTS OF RADIATION 



exposed Escherichia coli to rays from a Coolidge tube at 30 kv., and 

 35 to 45 ma. With constant voltage, they express their doses in miUi- 

 ampere-minutes ; these range from 245 to 3000. The Falk capillary cell 

 was used for electrophoretic measurements. They report totally nega- 

 tive results; no change in the charge on the cells. But the doses used 

 also produced no effect on the viability of the organisms, as determined 

 by direct counts. 



Van Bonin and Bleidorn (31) attempted to determine the relation 

 of roentgen-ray effects upon erythrocytes to their electric charge. They 

 measured the effects of various concentrations of lanthanum ion, which 

 is known to reduce the surface charge, upon the resistance of the cells to 

 saponin hemolysis and osmotic heniolysis. Their figures show that 

 lowering of the electric charge brings about proportional lowering of 

 hemolytic resistance. But roentgen irradiation (1 to 8 erythema doses, 

 filter 1 mm. Al + 0.5 mm. Zn) produced only a slight decrease in resist- 

 ance to hypotonic solutions and no change in resistance to saponin. The 

 authors conclude that roentgen rays do not act by lowering the surface 

 charge of cells. The contention is not proved unless the authors can 

 show that their doses had some effect on the cells. 



Straub and Gollwitzer-Meier (353, 354) disclaimed electrokinetic 

 methods and attempted to deduce the relative surface charges of human 

 blood cells in suspension from the irregularities of their CO2 dissociation 

 curves. There seems to be no information concerning radium effects 

 upon surface charges of cells except these deductions of Straub and 

 Gollwitzer-Meier. The work of these authors and the experiment of 

 Van Bonin and Bleidorn are obviously indirect. Dozois, Tittsler, Lisse, 

 and Davey obtained negative results but used doses without any appar- 

 ent biological effect. The study of this problem, of the effect of roentgen 

 and radium irradiation on electrical charges, presents a field virtually 

 untouched. 



A large literature has grown up around changes in the sedimentation 

 velocity of blood corpuscles; this seems, if the law of Stokes holds, to 

 depend on the degree of aggregation of the corpuscles and hence probably 

 on their surface charge. This interpretation is maintained by Mond 

 (262) who used ultra-violet rays and by Brummer (49, 50) experimenting 

 with roentgen rays. Nevertheless, there is no consistency in the results. 

 Some authors find an increase in the sedimentation velocity, as Brummer, 

 and Valeef (373), who used thorium X in vivo; Klein (1923) found that 

 roentgen rays caused acceleration in some cases, retardation in others. 

 MicuUcz-Radecki (261) believes that the reaction depends on the interval 

 between radiation and measurement. Mond (262) obtained both 

 acceleration and retardation. Rubin and Glasser (319), after finding 

 that the acceleration of sedimentation by roentgen rays was prevented 

 by a filter which protected the suspensions from the heat of the apparatus, 



