Dr. J. O. W. Barratt. 



[Aug. u, 



Table II. — Experiments to Determine the Degree to which Eed Blood-cells must be 



Eabbit A, and the Eed Blood-cells 





Duration 





Phagocytosis* (the dilution 





No. of 

 experi- 

 ment. 



of action of 

 red blood- 

 cells on 



At tem- 

 perature of — 







B * 



1 6 



8 



4 



.3 



2 









serum. 





s ~^- 



1 ' 



1* 







1* 



i 





1 



2 hours. 



37° C. 















(1 in 256) 





2 



33 























3 



„ 























4 



„ 























5 



» 



















+ 

 (1 in 512) 





6 



33 







! 















6 



33 























6 



33 























6 



33 























7 



33 







(Iinl4) 



(1 in 7) 



(1 in 7) 





+ + 



(1 in 7) 









8 



33 











(1 in 10) 



(1 in 10) 





(1 fa 7) 







9 



" 













(1 in 10) 





(1 in 10) 







10 



33 













(1 in 100) 





+ + 

 (1 in 100) 







11 



33 























* Phagocytosis was tested by sensibilising the washed red blood-cells of guinea-pig's blood (B) with the serum 

 the rabbit's serum were taken. After sensibilisation the red cells were washed in 85-per-cent. sodium 



0*2 to 0*6 per cent, of the leucocytes ingested red blood-cells 

 instance 9 per cent., in another 10 per cent.). 



+ + that 0"8 to 1*3 per cent, contained 



I 



was carried out. Portions of the serum of Eabbit A, diluted with an equal 

 volume of 085-per-cent. sodium chloride solution, were mixed with the 

 washed red cells of guinea-pig blood in the proportion of 4 : 1, for periods of 

 time varying from 5 minutes to 3 hours and 20 minutes, and subsequently 

 tested for the presence of opsonin, as in previous experiments (A to D, 

 Table III). A second (E to H), and third (I to M) series of the same character 

 were also carried out, the serum being diluted to 1 in 8 and 1 in 7 

 respectively. The tests of phagocytosis were made in groups, sometimes 

 with diminishing amounts of the same serum (arranged horizontally in 

 Table III), as in Experiments 1 to 18, sometimes with serum deopsinated 

 for different periods of time (these experiments are marked with an asterisk 



