130 Drs. H. Chambers and S. Euss. Action of [May 1, 



Further evidence of the absence of leucocytes upon a radiated surface 

 and of their drift into a protected region is given by fig. 5, which was 

 obtained by screening the a-radiation from one-half of the capsule. The 

 motion of the leucocytes occurred at room temperature. 



To account for the enlargement of the area free of leucocytes when 

 incubation occurs previous to radiation, the suggestion is put forward that 

 the leucocytes are destroyed after making their way to the mica surface 

 and liberate some fluid products which have a destructive effect upon the 

 leucocytes in the surrounding zones. These products gradually diffuse away 



from the radiated area and effect the destruction of leucocytes quite outside 

 the direct stream of the a-rays. 



This observation was substantiated by a series of experiments in which 

 apertures of different sizes were used. The diffusion effect, measured by 

 the enlargement of the radiated region, was more pronounced the smaller 

 the aperture. 



The experiment has been described in which citrated blood was exposed 

 to the action of the emanation in a closed glass bulb and the degree of 

 haemolysis observed from time to time. Simultaneously with these 

 observations the opsonic content of the blood was compared with that of 

 the control. 



No a-rays. 



Fig. 5. 



The Action of the Radiations on Opsonin. 



