1911.] 



Radium Radiations upon Normal Blood. 



129 



the leucocytes do not reach a radiated region, but tend to drift into a 

 protected zone. The leucocytes do not, however, move as a direct result 

 of the a-radiation, for if incubation occur simultaneously with radiation, 

 leucocytes are found on the radiated surface, although to a modified extent. 



During the slow motion of leucocytes to the mica at room temperature, 

 changes are talcing place in the radiated serum, forming a layer over the 

 mica. As will be seen later, there is a lowering of the opsonin and com- 

 plement content of the serum over the radiated region. 



The leucocytes seem to move from a radiated to a n on- radiated region, 

 i.e., from a serum in which changes have been induced by the radiation, 

 to a serum which is unaltered. This motion can be explained by changes in 



surface tension corresponding to some alteration in the constitution of the 

 fluids in which the leucocytes are moving. 



The surface tension of «-radiated serum, determined by the capillary 

 tube method, showed a reduction when compared with that of a control 

 normal serum. The change is indicated by the figures in Table III. 



Table III.— Surface Tension in dynes per cm. at about 10° C. 



Normal s 



Time of radiation. 



VOL. LXXXIV. — B. 



K 



