96 PKOPERTIES OF ILEMOLYTIC SERA 



normal serum with an equal volume of 0-85 per cent, salt 

 solution added to it was filtered at the same time through 

 another filter, and the filtrate was diluted with 0-85 per cent, 

 salt solution, so as to make it of equal bulk to the other. 

 The hsemolytic action of the two fluids was then tested. The 

 following are examples of such experiments, the haemolytic 

 dose being expressed in terms of the actual amount of serum 

 necessary to bring about complete lysis. 



EXAMPLE 1. Dose of complement before filtration . . 0-005 c.c. 

 filtered in usual way 



about . . .0-5 

 filtered in 5 per cent. 



salt solution . . 0-0085 



It is thus seen , that while only about one-hundredth part of the 

 complement originally present has passed the filter by the ordinary 

 method of filtration, more than half the complement has passed 

 the filter in the presence of 5 per cent, sodium chloride. 



EXAMPLE 2. Dose of complement before filtration . . 0-01 c.c. 

 ,, filtered in usual way 



about . . . 0-13 

 filtered in 5 per cent. 



salt solution . . 0-01 



In this case practically all the complement in the salted serum 

 has passed. 



EXAMPLE 3. Dose of complement before filtration . . 0-006 c.c. 

 ,, filtered in usual way . 0-2 



filtered in 5 per cent. 



salt solution . . 0-013 



In this case, fully a half of the complement in the salted serum 

 passed the filter. 



It is thus evident that the addition of an amount of salt 

 sufficient to inhibit the haemolytic action of complement 

 prevents in some way, which we cannot at present explain, 

 the retention of complement in the pores of the filter. 



