255 



On the Fate of Red Blood Corpuscles when Injected into the 

 Circulation of an Animal of the same Species ; with a Neiv 

 Method for the Determination of the Total Volume of the 

 Blood. 



By Charles Todd, M.D., Bacteriologist, Egyptian Government ; and 

 R G. White, M.B., Director, Serum Institute, Cairo. 



(Communicated by Dr. C. J. Martin, F.R.S. Eeceived July 1, 1911.) 



(From the Hygienic Institute, Public Health Department, Cairo.) 



In a paper published last year* the authors described a method by which 

 it is possible to recognise the red blood corpuscles of any individual ox and 

 to differentiate them from those of any other member of the same species. 



The method depends upon the fact that if a highly polyvalent isohsemolytic 

 serum is treated repeatedly with the red blood corpuscles of any individual 

 of the species for which the serum has been made, it entirely loses its 

 hemolytic action for the corpuscles of all other individuals of the same 

 species.f Such a serum therefore constitutes, so to sp6ak, a specific reagent 

 for the corpuscles of the individual for which it has been prepared, and by its 

 means one is enabled to follow up and to identify these corpuscles even in 

 the presence of corpuscles of other individuals. 



Being in the possession of such a method we were led to investigate the 

 fate of the red blood corpuscles of one animal when these are injected into 

 the circulation of another animal of the same species, as in ordinary trans- 

 fusion. As the serum at our disposal was prepared for cattle, the investigations 

 were made with the blood of these animals, and the experiments were 

 carried out as follows : — 



Two suitable bulls (A and B) having been chosen, each was bled from the 

 jugular vein — about 100 c.c. — in order to obtain the required corpuscles, 

 which were washed in normal saline, four washings being found sufficient for 

 this purpose. 



A highly polyvalent isohaemolytic cattle serum was then " exhausted " for 

 the corpuscles of A by being mixed with an equal volume of these 

 corpuscles. The mixture was allowed to stand for an hour at 37° C. and then 

 centrifuged — the supernatant serum being pipetted off and again treated 

 with an equal volume of the same corpuscles, and the process repeated four 



* ' Boy. Soc. Proc.,' 1910, B, vol. 82. 



t This rule is liable to certain exceptions in the case of close blood relations. 



