540 



Dr. R. D. Keith. Relationship betiveen [Feb. 15, 



The main question at issue, then, is whether the amboceptor, and by this I 

 mean that acting in haemolysis, is identical with the substance inducing the 

 phagocytosis of erythrocytes — the opsonin of Wright and Douglas. 



As Savtchenko and Barratt did not use exact quantitative methods in 

 their experiments, and as such are desirable, it has been necessary to use a 

 somewhat different technical procedure from that employed by these 

 researchers, but the type of experiment was essentially the same as theirs. 



Production of the Immune Serum, etc. 



The materials used were the red blood cells of the ox, the serum of a 

 rabbit immunised against these, and normal human leucocytes as the 

 phagocytic agents. 



The rabbit received intra-peritoneally doses of 10 c.c. of washed ox 

 corpuscles at intervals of a week, 30 c.c. in all being administered before 

 experiments were commenced. 



The last injection was made on November 13, 1905. On the 27th of the 

 same month it was found, testing in the usual way, that - 002 c.c. of the 

 serum produced, when fully complemented, total hcemolysis of 2 c.c. of a 

 T>-per-cent. suspension in normal saline of washed ox corpuscles, after 

 two hours at 37° C. and 12 hours at room temperature. 



On the Effects of Heat on the Substances in the Serum which Induces Hcemolysis 



and Phagocytosis. 



The first point to be studied was the influence of heat on the phagocytic 

 action of the serum. With the undiluted unheated serum it was found to be 

 a matter of considerable difficulty to perform phagocytic tests owing to 

 haemolysis somewhat obscuring phagocytosis. With the undiluted unheated 

 serum only blood shadows were to be seen in the phagocytes, but on diluting 

 the serum sufficiently to suppress the effects of the complement, haemolysis 

 was abolished and the red cells could be observed to be phagocytosed, 

 apparently in their normal condition. 



In order to find approximately at what degree of dilution haemolysis 

 would cease to come into play, a series of hsemolytic tests were performed in 

 capillary pipettes. This method was employed in preference to that 

 ordinarily adopted, because with Wright's method of performing phagocytic 

 tests, to deal with absolute quantities is a matter of considerable difficulty. 



Experiment. — Various dilutions of the unheated.- immune serum were made 

 and equal parts of these dilutions and of a 5-per-cent. suspension of the 

 washed red blood cells of the ox were mixed in a series of capillary pipettes, 

 so that the ultimate proportion of serum in the mixtures varied from 1 in 2 



