1904] Combining Properties of Serum-Complements, etc. 



15 



2. 0'05 c.c. anti-Gin each tube. 

 A. 



In this case of course, as already explained, the surplus C comes off 

 much more gradually, and a more accurate result might be expected. 

 The theoretical consideration of all the factors, however, is one of 

 much complexity, and we do not claim to explain it fully. The 

 following points are to be noted however: (1) The amount of C 

 obtainable has been estimated by the amount of lysis the two, how- 

 ever, only approximately correspond it is not possible to detect the 

 smallest amount of C, we can only note ihe first appreciable lysis ; 

 (2) as has been stated, the combining value of C (fresh serum) 

 usually falls somewhat when converted into Cd. (Unfortunately a 

 separate estimation of the exact value of Cd in the experiments 

 before us was not made) ; (3) when there is a surplus of C and Cd 

 molecules the former are taken up by the intact corpuscles treated 

 with IB, the latter not at all ; the balance of dissociation may thus 

 be affected. 



Looking, however, at the results in a general way, we see that C 

 is kept out of combination by Cd, that the points at which surplus 

 C is obtained are not far distant from each other in the two series, 

 and that the interval from the point at which C is first obtainable to 

 that at which a full dose is got is much lengthened in series B, 

 though it is not quite doubled. If we take the tube in series B 

 (mixture of C and Cd added), which gives a third lysis in the added 

 corpuscles, we find that the corresponding tube in series A (C alone 

 added) gives about two-thirds lysis. We may thus conclude that 

 with anti-C also the firmness of union of Cd does not differ greatly 

 from that of C. 



On the Union of Complementoid with R + IB Molecules before Lysis. 

 As has been mentioned above, the addition of complementoid to red 

 corpuscles treated with IB does not prevent the subsequent action of 



