542 Mr. L. 8. Dudgeon. On the Presence of [July 31, 
result of some interesting experiments :—“ That the substance which induces 
phagocytosis is partially destroyed by heat, while the hemolytic amboceptor 
is entirely thermo-stable.” And secondly: “The hemolytic amboceptor 
may be present in considerable amount in a hemolytic serum without 
inducing phagocytosis, notwithstanding prolonged contact of the amboceptor 
with the red blood cells.” 
The experiments referred to in this communication entirely agree with the 
observations of Barratt and Keith, conducted with the blood sera and cells 
from the lower animals. There was nothing to show that the agglutinative, 
opsonie, or heemolysing properties of normal or immune sera on red blood 
corpuscles have any direct relation to one another. 
Heemo-lysins. 
Technique-—A 5-per-cent. suspension of washed red cells in 0°85-per- 
cent. saline in distilled water was employed for these experiments. Normal 
red cells were allowed to act in the presence of normal serum and immune 
serum, immune red cells in normal serum, immune red cells in immune 
serum, and normal and immune red cells in immune serum, to which a 
definite volume of native and foreign complement had been added. 
The serum to be tested was always carefully noted to be free from any 
blood tinging. 
The mixture of red blood corpuscles, serum, and salt solution was 
incubated, usually for two hours, immersed in sealed glass tubes in water at 
37° C., and placed in an incubator at the same temperature. In some cases 
the incubation period was considerably extended, but two hours was found 
to be sufficient. At the end of that time the tubes were put in the ice-safe 
and examined at the end of about 12 hours. The actual dilutions which 
were employed were as follows:—The capillary tubes were carefully 
graduated, and in each tube, in every experiment, the total contents 
amounted to four volumes, of which one volume of washed red cells was a 
constant quantity, and the amounts of serum and salt solution were in 
inverse ratio; the first tube contained one volume of washed red cells and 
three volumes of serum, without any salt solution, while the tenth tube in 
each series contained 2°5 volumes of salt solution and 0:005 volume of serum. 
It should be noted that the strength of the salt solution employed for 
these experiments was 0°85 or 0:9 per cent., but it was found in these 
investigations that certain red cells underwent some degree of hemolysis 
when presented to a 0°9-per-cent. salt solution. This is a most important 
fact, because it shows that physiological salt solution has a power of heemo- 
lysing immune human red cells under certain conditions. This special 
