1908.] Hem-agglutinins, etc., in the Blood. 5Al 
of the leucocytes contained red blood corpuscles, the phagocytic mixture 
consisting of the immune red cells, normal serum, and normal leucocytes. 
In the same experiment, conducted with immune serum, only three cells were 
phagocytic. 
The next case was an example of severe anemia, secondary to hemorrhage, 
in which 16 per cent. of the leucocytes were phagocytic. In this experiment, 
as in the last, the higher degree of phagocytosis occurred by the interaction of 
normal serum and immune red cells. 
In a case of'acute peritonitis and appendicitis, 20 per cent. of the leuco- 
cytes were phagocytic, but in this experiment the higher degree of phago- 
cytosis occurred by the interaction of immune serum and immune red cells, 
in conjunction with normal leucocytes. 
In all the other experiments it was often found that 5 to 10 per cent. of 
the leucocytes contained one red blood corpuscle, while in many instances 
there was no phagocytosis present. 
It has been suggested that one of the main causes of anzemia is due to the 
presence in the patient’s serum of a certain substance which acts upon the 
red blood corpuscles, which in turn became devoured by the leucocytes. 
There is nothing in these experiments to support this view. In those cases 
in which the anemia was most intense, the phagocytosis was present to an 
infinitesimal degree, while in the cases previously referred to in which the 
phagocytosis of the red blood corpuscles was such a striking feature, the 
anemia was quite of a mild type. 
As I have already stated, there was no relation in these experiments 
between the extent of the agglutinative, hemolysing, and opsonic properties 
of the same serum. A very large number of these immune sera had a more 
or less high degree of agglutinative action, yet the degree of hemolysis 
which they were capable of producing was only occasionally striking, and the 
opsonic property was the least marked. Barratt,* in his experiments, 
conducted with the blood of the lower animals, has shown that even with 
unheated immune serum, phagocytosis of red blood cells can occur without 
the serum having either hemolytic or agglutinative properties, and he 
favours the view that the phagocytosis is induced by some body which can 
be placed amongst the order of opsonins. R. D. Keith, in a paper also 
published in the ‘ Proceedings of the Royal Society, from work done in the 
laboratories of the London Hospital, came to the following conclusions as the 
* Barratt, “The Phagocytosis of Red Blood Corpuscles,” ‘Roy. Soc. Proc.,’ 1905, vol. 76, 
Ser. B, p. 524. 
+ R. D. Keith, “On the Relationship between Hzemolysis and the Phagocytosis of Red 
Blood Cells,” ‘Roy. Soc. Proc.,’ 1906, vol. 77, Ser. B, p. 537. 
