400 



Mr. W. W. C. Topley. 



had a definite lytic action on sheep corpuscles when allowed to act on them 

 for one hour at 37° C. in a salt-free medium, the haemolysis varying with 

 different sera from the merest trace to complete solution. 



A few sera which, when untreated, produced haemolysis, failed to do so after 

 the preliminary absorption, while a few others produced no lysis before or 

 after treatment. The lysis was never very rapid ; thus in no case was 

 complete solution ever observed in less than 30 minutes. 



Inactivation at 55° C. for 30 minutes completely destroyed the activity of 

 every specimen of serum examined in this way. 



In a preliminary series of experiments fresh guinea-pig serum was absorbed 

 with sheep corpuscles, and then varying amounts were added to 005 c.c. of a 

 50-per-cent. suspension of sheep's red cells contained in 1 c.c. of 7'8-per-cent. 

 saccharose solution. The following results may be taken as typical : — 



Experiment. — A series of tubes was put up, each containing 1 c.c. of 

 7"8-per-cent. saccharose solution and 0'05 c.c. of a 50-per-cent. suspension of 

 sheep corpuscles. Varying amounts of the complementary serum were then 

 added and the whole series incubated at 37° C. for one hour. A control tube, 

 containing the same amount of red cells suspended in 7"8-per-cent. saccharose 

 solution to which had been added 0"8 per cent, of sodium chloride,* and the 

 maximum amount of complement employed, was put up ; also a similar tube 

 with the addition of 4 M.H.D. of hemolysin. 



Amount of complement 

 added to salt-free tubes. 



Haemolysis in 1 hour 

 at 37° 0. 



c.c. 





o-o 



None. 



0-05 



Moderate. 



0-075 



Marked. 



o-i 



Slight. 



0-125 



Trace. 



0-15 



None. 



-175 





0-2 





0-225 



j) 



0-25 





Controls. 



Haemolysis in 1 hour 

 at 37° C. 



In 1 c.c. of 7 "8 per-cent.' saccharose containing - 8 per cent, 

 sodium chloride : — 



(2) 0-05 c.c. red cells + 0-25 c.c. complement + 4 M.H.D. 

 haemolysm 



No haemolysis. 

 Complete haemolysis. 



* This medium is hereafter referred to as " normal saline-saccharose solution." 



