364 



Dr. A. E. Wright and Capt. S. 11 Douglas. [Sept, 1, 



B. S. R D.'s heated serum, staphylococcus supension, and corpuscles 

 in the same proportions as before. 



Phagocytie power (bacteria in 45 P.W.B.C. counted and 

 averaged) 0'2 



These experiments show that we must ascribe an important role to 

 the blood fluids in connection with phagocytosis. 



For the alternative assumption, the supposition, to wit, that inhibiting 

 elements are developed in the serum during the process of heating, is 

 rebutted by the results of a series of control experiments, which showed 

 that the phagocytes display no greater activity in a medium of 

 physiological salt solution than in a medium of heated serum. 



It is further rebutted by the circumstance that the activity of 

 phagocytosis falls off at the same rate when the unheated serum is 

 diluted with salt solution as when it is diluted with heated serum. 



The experiment whose results are tabulated below illustrates this 

 last point. 



Results of a Comparison made between the Activating Poiver of (a) Unheated 

 Serum diluted in Heated Serum, and (b) Unheated Serum diluted in 

 Physiological Salt Solution. 



In each case 3 vols. of serum dilution were mixed with 1 vol. of 

 staphylococcus suspension and 3 vols. of washed corpuscles. 



It is clear that we may conclude that the heated serum, like the 

 salt solution, acts merely as an inert diluent, and that we may, in 

 referring to such heated serum, characterise it simply as " inactivated 

 serum." It is further clear that we may legitimately ascribe the 

 small amount of phagocytosis which occurred in Experiments 1, 

 2, and 4 supra, to the presence of a residuum of unheated serum, 

 which the washing operations had failed to separate from the 

 corpuscles. 



