126 



Drs. H. Chambers and S. Buss. Action of 



[May 1, 



brass capsule (fig. 1). The grains were held in position by very thin varnish. 

 The cavity was covered with an air-tight sheet of mica (A), sufficiently thin 

 to allow escape of the a-particles.* 



On another thin sheet of mica (B) a drop of citrated blood (C) was spread 

 over a known area. The drop was covered over with a shallow watch- 



A Radium 



S_ 



Fig. 1. 



glass (E), vaselined round its edge to prevent evaporation. The mica B was 

 then placed over A, and radiation proceeded for any desired interval. 



It was clear that, since the liberation of haemoglobin is a gradual process, 

 if an accurate relation between the time of radiation and the number of 

 hsemolysed corpuscles were to be found, sufficient time must elapse after 

 radiation and before the count was made, to allow of the release of the 

 haemoglobin from the affected corpuscles. Twenty-four hours were found to 

 be sufficient for this purpose. 



The same volume of citrated blood (12'5 c. mm.) was taken each time and 

 spread over an area of 1*5 sq. cm. on a sheet of mica. This was then exposed 

 to the a-radiation from the radium capsule.' A control was provided in 

 each case. 



It may be seen from Table II and the curve in fig. 2 that the number of 

 totally hsemolysed corpuscles for a given intensity of radiation bears a simple 

 relation to the time of exposure. A separate experiment showed that the 

 products of haemolysis had no hemolytic action on other red corpuscles. 



Table II. 



Time of 



exposure. 



Percentage of unh«molysed 

 corpuscles. 



h. 











15 



98 



1 







93 -5 



1 



40 



84-5 



4 



15 



. 58-8 



6 



35 



45 -6 



10 



45 



25 



24 







10 



* Two such brass capsules were made, one containing 2*4 mgrm., the other 3 - 27 mgrm. 

 EaBr 2 . We are indebted to Mr. F. H. Glew for their preparation. 



