JOINT ACTION OF SEVERAL AMBOCEPTORS. 643 



haemolysis (See Table 13, B). Despite the occurrence of this 

 haemolysis in which at least some material has been used up, the 

 final result is just the opposite of what was, a priori, to have been 

 expected. This furnished a weighty argument in favor of the view 

 we have brought forward. We shall probably not err if we assume 

 that the horse serum constituent c{3 is a complement, but that it is 

 dominant neither for amboceptor a nor amboceptor b. The ox serum' 

 thus plays merely the part of anticomplement. The amboceptors 

 of ox serum in general evidently possess a high affinity in their 

 complementophile groups. It will be recalled that we have actually 

 demonstrated this in the case of the amboceptor acting on guinea- 

 pig blood and complemented by horse serum. A little consideration, 

 however, will show that such amboceptors, when the cells on which 

 they act are missing, will exert an anticomplementary action. This 

 also explains how the inactivated ox serum when in excess, can 

 inhibit the haemolysis of strongly prepared ox blood by horse com- 

 plement ca, although this same ox serum, in smaller quantities, 

 brings this haemolysis about. This observation has been repeatedly 

 made by us. It is merely necessary to assume that ox serum also 

 contains very small quantities of complementophile groups a. 

 Large doses of the serum would then also exert a deflecting influence 

 on complement ca. 



So far as the two complements of horse serum are concerned 

 (cce and c/3) it seems as though their quantitative relations are 

 subject to certain fluctuations. We have already called attention 

 to the fact that horse serum alone dissolves prepared ox blood cells 

 to a varying degree. In the light of what has been said it is obvious 

 that the haemolysis produced by horse serum alone will be stronger 

 the more the concentration of the horse complement ca exceeds 

 that of complement c/?. If complement c/3 were entirely absent we 

 should find that the haemolysis produced by horse serum alone would 

 be as strong as that produced by the combined action of horse serum 

 and inactive ox serum. We have not met with such extreme cases. 

 Nevertheless we have observed horse sera which by themselves 

 produced complete haemolysis of prepared ox biood in doses of 0.35 

 to 0.3 cc. while the addition of inactive ox serum reinforced com- 

 plete haemolysis only to the extent of a dose of 0.15 cc. horse serum. 

 We see, therefore, that a critical study of the experimental findings 

 leads to conclusions which fit perfectly into the interpretation we 

 have elaborated. 



