540 Mr. L. 8. Dudgeon... On the Presence of [July 31, _ 
preparations were made and stained with Leishman’s stain. It is most 
important that the film preparations should be thin and rapidly dried, as 
otherwise the leucocytes retract owing to imperfect fixation, and the estimation 
of the phagocytosis becomes impossible. 
In some instances, the serum was heated to 55° C. for 20 minutes, and the 
phagocytic properties of the serum were then compared with those obtained 
with the unheated. 
It will be understood from the remarks which have already been given on 
this subject of phagocytosis of red blood corpuscles, that numerous methods 
were employed and comparisons made so as to ascertain the manner in which 
phagocytosis was most marked. It is unnecessary to refer at great length 
to the very large number of experiments made, as it was only in a few 
instances that phagocytosis was pronounced. In quite a number of instances, 
whether the serum was unheated, or diluted, or heated, or whether normal or 
immune leucocytes were employed, the degree of phagocytosis was infinitesimal. 
In every instance 50 or 100 leucocytes were counted, and the number of 
corpuscles engulfed was carefully noted. In the large majority of cases, out 
of 50 cells only three or four would be found to be phagocytic. There was 
only one instance out of the total number investigated 1n which the phago- 
cytosis of red blood corpuscles was a striking feature. This occurred in a 
case of jaundice, unfortunately of unknown origin. The immune red cells 
of the patient in the presence of the unheated undiluted immune serum from 
the same case and normal leucocytes gave a high degree of phagocytosis : 
56 per cent. of the cells were phagocytic, and there were 33 red blood 
corpuscles in the 50 cells. When normal red cells were used in conjunction 
with the same serum and normal leucocytes, as in the previous experiment, 
76 per cent. of the leucocytes were phagocytic, and 50 of these contained 
46 red blood corpuscles. 
In both these experiments, the serum, the leucocytes, and the red blood 
corpuscles were incubated in the capillary tubes in equal volumes for a 
period of 15 minutes at 37° C. The red cells stained well with eosin, 
showed no degenerative changes, and none of the leucocytes contained 
definite “Ghosts.” This serum was found to possess a high agglutinative 
property for normal red cells, but it was not tested on the immune red cells. 
It was found to be free from any hemolytic action, either on the patient’s red 
cells or on normal red cells. 
As previously mentioned, these were the only two examples out of some 
250 experiments made in which over 20 per cent. of the leucocytes were 
phagocytic. The other instances in which the phagocytosis was sufficiently 
pronounced to record were, firstly, a case of chlorosis, in which 20 per cent. 
