632 



COLLECTED STUDIES IN IMMUNITY. 



Prepared blood so treated, however, at once dissolves in a mixture 

 containing minimum quantities of horse serum and inactive ox 

 serum. This is illustrated in the following experiment: 



Two similar series of tubes are prepared. The tubes in each series contain 

 1 cc. 5% prepared ox blood and decreasing amounts of active horse serum (total 

 volume 2 cc.)- After remaining for two hours at 37 the tubes are centrifuged. 

 In the first two, containing the largest amounts of horse serum, a trace of 

 haemolysis was noticed. 



A. The supernatant fluids were mixed each with the sediments of 1 cc. 5% 

 prepared ox blood, plus O.I cc. inactive ox serum. (0.1 cc. is the smallest dose 

 necessary to produce complete haemolysis.) 



B. The sediments are suspended in salt solution plus 0.1 cc. inactive ox 

 serum. 



C. The sediments are suspended in salt solution plus 0.1 cc. inactive ox 

 serum plus 0.35 cc. horse serum. 



The result is shown in the following table: 



TABLE VIII. 



Column B of the table shows exactly the same behavior as in a 

 corresponding experiment with guinea-pig blood. Despite the fact 

 that horse serum has bound the amboceptor and complement, 

 there is no haemolysis on the addition of inactive ox serum. One 

 of the main arguments which could have been advanced in support of 

 Bordet-Gay's colloid theoiy thus fails. It is also apparent that no 

 special resistance of the prepared blood-cells comes into question, 

 for in column C we find that these cells are completely dissolved in a 

 suitable mixture. 



Bordet and Gay, to be sure, do say that prepared ox blood-cells 

 treated with horse serum absorb the effective principles of inactive 

 horse serum. However, all that they describe as a result of this is a 



