458 STUDIES IN IMMUNITY. 



ties markedly, and in particular would produce an avidity for 

 alexin absorption. Thanks to the researches of Gengou and of 

 Gay, we know that the albuminous substances of serum, of milk 

 and the like, become avid of alexin when precipitins are added. 



It does not seem, a priori, necessary that in each instance the 

 same result should occur. In certain other cases the facility of 

 different substances to clump together may be supposed to be due 

 to the presence of such tendencies of adhesion in each separate 

 substance. For example, if A, B and C clump one another it 

 may be supposed that one of these elements, B for example, 

 shows a property of adhesion both toward A and toward C, and 

 may show an intermediary function in producing the complex.* 



It would seem, in the case of conglutination, that alexin fills 

 such an intermediary function. It seems to unite on the one hand 

 with the sensitized corpuscle, as we already know, but it is also 

 evident that there is some reaction between it and the conglutinin. 

 To demonstrate this fact, we may take fresh horse serum, pre- 

 viously diluted with an equal volume of salt solution, and heated 

 bovine serum diluted in the same manner. We add 1 c.c. of the 

 diluted bovine serum to say 0.2 of a cubic centimeter of diluted 

 horse serum. This mixture is left for a time at room tempera- 

 ture. After a while another similar mixture is prepared, and 0.05 

 of a cubic centimeter of washed guinea-pig corpuscles is then 

 added to each of them. We find that the first mixture, in which 

 a longer contact has taken place, has lost its property of producing 

 conglutination and hemolysis almost entirely; in the second mix- 

 ture the phenomena occur well. 



The experiment 'may be repeated with modifications in the re- 

 spective doses of each serum or in the duration of contact. In the 

 doses we have given, a rather short contact suffices to diminish 

 the activity of the mixture, even 10 or 15 minutes being sufficient 

 to produce a distinct difference. As regards the dosage, it is found 

 that the depressing effect of contact becomes less and less distinct 

 as the quantity of the alexin is increased relative to the amount 

 of heated bovine serum. For example, in a mixture of equal parts 



* If this were so, B might well deserve the name of amboceptor, which Ehrlich 

 has incorrectly applied to sensitizers, with the reservation, however, that we are 

 now dealing with tendencies to adhesion and not with purely chemical affinities. 



