ON FILTRATION OF SERUM COMPLEMENT 99 



SUMMARY OF RESULTS 



1. In the early stages of filtration of normal serum through 

 a Berkefeld filter complement is in great part, sometimes 

 almost completely, removed from the serum, and the com- 

 plement retained by the filter is not recoverable. 



2. In the process of filtration the filter soon becomes 

 permeable to complement. Permeability can also be pro- 

 duced by the passage of serum previously deprived of com- 

 plement by heating. 



3. Complement rendered inactive by the addition of 

 5 per cent, sodium chloride passes through a Berkefeld 

 filter, the original value of complement being almost com- 

 pletely regained on making the necessary dilution of the 

 filtered salted serum. 



4. Immune-body passes through the filter practically un- 

 changed. It passes equally well when it is mixed with 

 a corresponding quantity of complement at 37 C. and 

 filtered at this temperature, while the complement is retained. 

 Such filtration experiments supply no evidence that com- 

 plement and immune-body unite at this temperature. 



H2 



