Dr. J. O. W. Barratt. 



[Aug. 11, 



Table I. — Deopsination of Serum of Eabbit A, by means of the Bed Blood-cells of 

 the Guinea-pig. Temperature of Experiment, 37° to 38° C. 



No. of 



Dilution 



of 

 serum. 



B* 



Phagocytosis.f 



[The duration of the deopsinating action of the red blood-cells 



expt. 



S " 





on the serum is given in brackets.] 









[5 min.]. 



[10 min.]. 



[20 min.]. 



[40 min.]. 



[lhr.]. 



[l-|hr.]. 



[2hr.]. 



[3hr.]. 



[4hr.].[5hr.]. 



1 



Iin8 



8 

 1 















— 









2 



Undiluted 



4 















— 









3 



1 in 8 



1 















— 









4 



Undiluted 

















- 









5 



>> 



iTe 









— 



— 





— 







— 



6 



lin8 



4 















— 









7 



lin2 









— 















— 



— 



8 



lin8 



4 















— 









9 



Undiluted 



55 















— 









10 



>> 



35 



+ + + 





+ + 







— 





— 







11 



lin8 





+ + + 





+ + + 







— 





— 







12 



Undiluted 



55 



+ + + 





+ + + 







+ + + 





+ 







13 



lin8 





+ + + 





+ + 







+ + 





+ 







14 



Undiluted 



55 



+ + + 





— 







— 





— 



" 





15 



1 in 8 



55 



+ + + 





+ + + 







+ + + 





+ + + 







16 



Undiluted 





+ + 





+ + 







+ 





+ 







17 



lin8 



J3 



+ + + 





— 







+ + + 





+ + + 







18 



Undiluted 









— 







+ + 





+ + 







19 



1 in 8 



JJ 







— 







— 







— 





20 



55 



5> 



+ + + 



+ + + 



+ + + 



+ + + 















21 



55 



" 







+ + 



+ + 















* The washed red blood-cells of guinea-pig's blood (B) were added to the serum of rabbit A (S) in the 



T> 



proportions given. Thus, —-== ~ means that eight parts of guinea-pig's blood and one part of the serum of the 



S 



rabbit were taken. 



f In order to test phagocytosis, the red blood-cells of 0*005 c.c. of guinea-pig's blood were sensibilised 

 with 1 c.c. of the deopsinated serum, diluted or undiluted, and then added to leucocytes obtained from 

 the guinea-pig. The sign — means that no phagocytosis occurred ; + that "2 per cent, to '7 per cent, of the 

 leucocytes contained red blood- cells ; + + that 1 per cent, to 1 *5 per cent, contained red cells ; + + + that 

 the maximum degree of phagocytosis was obtained (2 per cent, to 5 per cent., in one instance 10 per cent., in 

 another 20 per cent.). 



In these experiments the red blood-cells of gradually diminishing amounts of 

 guinea pig's blood were added to a given volume of the serum of Eabbit A, 

 and the whole shaken for two hours at 37° C, the red cells being then 

 washed and tested as to their power of exciting phagocytosis. It will 

 be seen that so long as the ratio of the former to the latter exceeds 3 : 1 the 

 red blood-cells are quite insufficiently sensibilised and fail to excite phago- 

 cytosis when added to the leucocytes of the guinea-pig. When the propor- 

 tion is 1:1, phagocytosis becomes marked,* and no further increase in the 



* The highest degree of phagocytosis obtainable was found to be that in which 2 to 

 6 per cent, of the leucocytes had taken up red cells at the end of 2 hours at 37° C. (after 

 2 hours little or no increase occurred). This range represents the variation to be expected 

 under the most favourable circumstances. Percentages of 20, 12 and 10 were occasionally 

 obtained, but were quite exceptional. 



