98 PROPERTIES OF H^MOLYTIC SERA 



0-005 c.c.) and one hundred doses of immune body (hsemolytic 

 dose, 0-003 c.c.). Filtration at 37 C. 



Dose of complement before nitration . . . 0-005 c.c. 



after nitration . . . . 0-15 



Dose of immune-body before nitration . . . 0-003 ,, 



after filtration . . . 0-003 



EXAMPLE 2. Four hundred doses of complement and four hundred 

 doses of immune-body : incubated for one and a half hours at 

 37 C. and then filtered. 



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



after filtration, about . . 04 



Dose of immune-body before filtration . . . 0-0008 



after filtration . . . 0-0008 



EXAMPLE 3. One thousand doses of complement and four hundred 

 doses of immune-body filtered after being allowed to stand for two 

 hours at room temperature. 



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



after filtration . . . 0425 



Dose of immune-body before filtration . . . 0-0025 ,, 



after filtration . . . 0-0025 



In all these examples it is seen that the immune-body 

 passes through the filter unchanged in amount, even when 

 it is associated with a large quantity of complement. The 

 complement, on the other hand, undergoes a marked reduc- 

 tion, just as in the previous experiments. Accordingly, so 

 far as this method of investigation shows, there is no indica- 

 tion that immune-body unites with complement at the 

 temperatures at which complement is known to act, namely, 

 room temperature and especially at 37 C. It might be 

 suggested that complement unites with immune-body, but 

 that the union is of such a loose nature that the two sub- 

 stances are separated in the process of filtration. This, 

 however, appears rather an extravagant supposition, and is 

 one for which we have no evidence. 



