272 COLLECTED STUDIES IN IMMUNITY. 



organs, on the other. He believes to explain this by assuming a 

 difference in the macrocytase extracted from the organs and that 

 present in the serum. In any case this constitutes a serious dilemma 

 for Tarassevitsch; for either there are several "macrocytases" as 

 opposed to the Unitarian view of Metchnikoff or the macrocytase of 

 serum is identical with that of the organ extracts. In view of this 

 entirely different behavior, however, the latter does not appear 

 acceptable to Tarassevitsch. 



Our first question was an entirely different one, for in all the cases 

 of haemolysis and bacteriolysis sufficiently examined we had never 

 met with a simple alexin in the sense of Buchner and Metchnikoff, but 

 invariably found a coaction of amboceptor and complement. In view 

 of this our investigations had, above all, to determine whether the 

 hsemolytic organ extracts could be shown to be characterized by 

 complement and amboceptor. 



These first doubts, namely, whether these substances corresponded 

 to what we conceive as the complex haemolysins of blood-serum, led 

 us to study the hsemolytic organs in respect to those main character- 

 istics which we have come to know in our study of the complex hae- 

 molysins. These are: 1. The behavior toward thermic influences. 

 2. The behavior when bound to the red blood-cells at low tempera- 

 tures. 3. The power of producing antibodies by immunization. 



We shall begin by describing a number of typical experiments which 

 show the behavior of the organ extracts toward higher temperature. 

 Let us glance first at the experiments dealing with the effect of organ 

 extracts on goose blood-cells, for this is the blood species which has 

 been mainly used by Metchnikoff and Tarassevitsch. (See Table II.) 



These experiments clearly show that in most of the cases the 

 haemolytic action of organ extracts on goose blood-cells is not at 

 all or but slightly affected by a three-hour heating, to 62 C., and that 

 heating to 100 C. for one hour and even for three hours does not 

 produce any further damage. Only the hsemolytic effect of extract 

 of mouse intestine is reduced to about one-half by the heating to 

 62 C. ; heating to 100 C. for three hours causes but little additional 

 damage. But that this cannot be a true destruction of part of the 

 hsemolysin will be discussed later. We wish next to present additional 

 experiments dealing with the behavior of heated organ emulsions on 

 guinea-pig blood. (See Table III.) 



Nor is this result changed if stronger agents, such as alkalies or 

 acids, are employed at high temperatures. (See Table IV.) 



