CONCERNING ALEXIN ACTION. 183 



complement for any given amboceptor. In testing a series of com- 

 binations, therefore, the finding of a suitable complement will to a 

 certain extent be merely a coincidence. In all the cases studied 

 at this Institute, however, even though often only after consider- 

 able labors, this has always led to a certain realization of the com- 

 plex nature of the haemolysin. 



Buchner was successful in two of his cases in activating the combi- 

 nation chosen by him: blood-cells A + inactive serum (amboceptor) B 

 -\-active serum (complement) A. (Guinea-pig blood and ox serum; 

 goat blood and rabbit serum.) In three other cases, however, he 

 was unable with a corresponding mode of procedure to restore the 

 solvent power which had been lost by inactivation. Guinea-pig 

 blood and sheep serum (Case I); sheep blood and rabbit serum 

 (Case II); guinea-pig blood and dog serum (Case III). These results, 

 to be sure, are contrary to those of Ehrlich and Morgenroth, who 

 observed more or less marked haemolysis in these same combina- 

 tions. These opposing results are, however, explained first by the 

 fact that the amount of complement contained hi the serum of the 

 same species is subject to individual and chronological variations 

 within wide limits. Beside this, recent experiences, which we shall 

 subsequently discuss in detail, have shown us that the temperature 

 at which the serum is inactivated is not indifferent for the function 

 of the amboceptor. Hence it appears significant that in these experi- 

 ments Buchner inactivated the sera by heating to 60 C., whereas 

 ordinarily this is done at 56-57 C. As a matter of fact, Buchner's 

 experiment No. 6 shows that dog serum, in this experiment inac- 

 tivated by heating only to 57 C., is activated hi its haemolytic action 

 for guinea-pig blood by rabbit serum. In view of this, the nega- 

 tive 7 findings of Buchner in Case III lose their significance. 



In the three cases looked upon by Buchner as negative, I tried, 

 by separation by means of cold, to convince myself of the presence 

 of two substances effecting the haemolysis. My method of pro- 

 cedure was as follows: 



Two parallel series of tubes of blood containing decreasing amounts 

 of active serum were prepared, kept at C. for 2-3 hours and then 

 centrifuged. The decanted fluid of one series was then allowed to 

 act on the sediments of native blood, that of the other series on the 

 sediments of blood which had been treated with a like quantity of 

 inactivated serum. The amount of blood, as in all our experiments, 

 was 1 cc. of a 5% suspension in .85% salt solution. 



