The Influence of Salt- Concentration on Haemolysis. 401 



It is clear from this experiment that only a certain definite amount of 

 complement will cause haemolysis, an increase or decrease in this amount 

 leads to a rapid reduction and final disappearance of the lytic action. 



These results are wholly unlike those obtained when working with a 

 complete hemolytic system reacting in normal saline solution. It seemed 

 possible that they might be explained by the fact that in increasing the 

 amount of complementary serum we necessarily increase the amount of 

 electrolytes, and that hence we might pass the limit at which complement 

 could be absorbed by the red cells in the absence of a hemolytic antibody. 

 Experiments carried out to test the validity of this explanation gave very 

 definite results. 



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

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

 washed sheep corpuscles. After the addition of the constituents mentioned 

 below, the whole series was incubated for one hour at 37° C. 



Tube. 



Hemolysis in 

 1 horn- at 37° C. 



1 



2 

 3 

 4 

 5 



6* 



7 



8 



Each tube contained 1 c.c. of 7 '8-per-cent. saccharose solution + 

 '05 c.c. red cells 



+ "05 c.c. complement 



+ 0-10 „ 



+ 0-25 „ 



+ '05 ,, +0 '05 c.c. 'S-per-cent. saline 



+ 0-05 „ +0-20 „ 0-8 „ '. 



+ 0-05 „ +0 -05 „ hemolysin 



+ 0-05 „ +0-20 „ „ 



+ 05 c.c. complement + '05 c.c. hasmolysin + '05 c.c. 

 inactivated complement 



Almost complete. 

 None. 



Slight trace. 

 None. 

 Complete, 

 ji 



None. 



* The haemolysin was diluted with normal saline so that - 05 c.c. contained 2 M.H.D. 



This experiment shows that it is the raised salt concentration which pre- 

 vents the haemolysis in the tubes containing the higher quantities of comple- 

 mentary serum. Thus, - 05 c.c. of complement causes almost complete lysis 

 while 0"25 c.c. causes none. But 005 c.c. of complement + 0"20 c.c. of 

 8-per-cent. saline also produce no lysis. 



It will be noted also that in this experiment the addition of a hemolytic 

 serum causes increased lysis, but if we also add 0"05 c.c. of the same serum 

 which was employed as complement, previously heating it at 55° C. for 

 30 minutes, no lysis results. Here, again, the effect of increased saline 

 concentration in combating haemolysis is clearly seen. 



These results help to explain those obtained by Sachs and Terruuchi, 

 which led those observers to deny the identity of the htemolysis produced 



