ON FILTRATION OF SEBUM COMPLEMENT 95 



solution in order to pass through as quickly as serum. 

 About 10 c.c. of diluted egg-white was passed through, and 

 then the filter was tested as before. Result 



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

 after filtration . . . . 0-15 



Thus only about one-fifteenth part of complement passed 

 through the treated filter, a quantity which is not greater 

 than may sometimes be obtained with a fresh filter. 



We have also investigated the effect of temperature on the 

 process of filtration, but have obtained varying results. 

 The earlier experiments seemed to show that complement 

 passed the filter in large amount at C., but in further 

 experiments with fresh filters we found that complement 

 might be retained as effectively at this temperature as at 

 37 C. We can at present make no definite statement on 

 this point. 



EFFECTS OF SALT CONTENT ON FILTRATION 



In the progress of our experiments, the question occurred 

 to us whether there might not be some relation between the 

 retention of complement by the filter and the combining 

 activity of complement. As is well known, the latter does 

 not combine at 0C. with red corpuscles treated with immune- 

 body, and experiments were carried out to determine the 

 effects of filtration at different temperatures. The results 

 have just been stated. The union of complement with 

 sensitized corpuscles is also prevented by a certain concen- 

 tration of salt solution, and we accordingly tested whether 

 the process of filtration was influenced by the amount of 

 salt in the fluid. The method used was to add an equal 

 quantity of 10 per cent, sodium chloride solution to fresh 

 guinea-pig's serum, and then to filter the mixture. The 

 filtrate was then diluted with distilled water so as to restore 

 the salt concentration to 0-85 per cent. A quantity of 



