1905.] The Phagocytosis of Red Blood-Cells. 525 
from the following amounts of hen’s blood were injected: on the ist day, 
6 c.c.; on the 6th day, 6 cc.; on the 15th day, 9 c.c.; on the 38th day, 5 e.. 
On the 45th day the animal was killed. Some leucocytes from a dove, 
together with erythrocytes from a hen, were added to a small quantity of the 
serum of the injected animal. After the lapse of an hour, at 37° C., about 
half the leucocytes present contained one or two, or rarely more, red blood- 
cells. 0°5 cc. of the serum of the injected animal was added to 1 cc. of a 
2°5 per cent. suspension in 0°85 per cent. sodium chloride solution of hen’s 
erythrocytes, and the volume of the mixture then made up to 2 cc. by the 
further addition of 0°5 cc. of the salt solution. At the end of 5 minutes 
agglutination was complete; at the end of 24 hours, at 37° C., no trace 
of hemolysis was perceptible. Smaller amounts of serum were also employed, 
with negative results, as far as the production of hemolysis is concerned. 
It follows from this experiment, therefore, that the presence of amboceptor 
is not causally related to the development of phagocytosis, since phagocytosis 
can occur in the absence of amboceptor. 
It was also found that, in most of the experiments made, agglutinin was 
present, and the enquiry presented itself whether agglutinin was essential to 
phagocytosis. It was found, however, that in some cases phagocytosis made 
its appearance in sera which possessed no agglutinating power for the 
red blood-cells employed. Among experiments illustrating this point are 
the following :— 
Hapervment 2.—Into the abdominal cavity of a rabbit, the red blood-cells 
obtained from the following amounts of calf’s blood were injected: on 
the 1st day, 20 c.c.; on the 6th day, 20 cc.; on the 17th day, 80cc. On 
the 24th day blood was taken from the animal and serum obtained. To a 
small amount of this serum, after inactivation by heating to 58° C. for 
30 minutes, leucocytes from the rabbit and erythrocytes from the calf were 
added. At the end of half an hour at 37° C., well-marked phagocytosis had 
occurred, about one-third of the leucocytes present having taken up one to 
three red blood-cells. To test the agglutinating power of the serum, which 
before inactivation was strongly hemolytic, the following tests were made: 
to four test-tubes, each of which contained 1 c.c. of a 2° per cent. sus- 
pension (in 0°85 per cent. NaCl solution), 0°5 cc. 0°25 cc, O1 cae, and 
0:05 c.c. of inactivated serum respectively were added, and the bulk of fluid 
in each test-tube made up to 2.cc. At the end of 24 hours, at a temperature 
of 37°, no agglutination had occurred in any of the tubes. 
Experiment 3.—Into the abdominal cavity of a guinea-pig the red blood- 
cells obtained from the following amounts of calf’s blood were injected: 
on the Ist day, 3 cc.; on the 3rd day, 10 cc.; on the 14th day, 7 ce. 
