248 LECTURES ON IMMUNITY 



which were generally prepared simply by the injection of 

 the normal serum of one animal into the veins of another 

 animal. As will be seen from the following accounts of 

 the results of experiments, the sera thus prepared seem 

 to contain anti-immune-bodies as well as antialexins. 1 And 

 regarding the relative probability of the production of 

 these two antibodies, it must be said that as the immune- 

 bodies are very much more rare than the alexins, the 

 organism will more easily produce the necessary quantity 

 of anti-immune-bodies than of antialexins. Moreover, the 

 serum of the animal which is exposed to dangers of a 

 haemolytic nature contains in its blood-serum generally 

 an alexin which, united with the proper immune-body, 

 haemolyses its own erythrocytes. Against this alexin the 

 animal evidently produces no antibody, for otherwise 

 the alexin would be of no use against foreign substances 

 which enter the blood. 



Morgenroth and Sachs 2 have carried out an investiga- 

 tion on the quantities of antialexin which are necessary 

 to completely suppress the action of a mixture of immune- 

 body and alexin which is just able to produce complete 

 haemolysis of the erythrocytes used in the experiment. 

 The results are given in the following table, where a 

 denotes the quantity of immune-body (given as number 

 of c.c. of the preparation used), b the corresponding quan- 

 tity of alexin, and c the quantity of antialexin necessary 

 to inhibit the haemolysis. The erythrocytes were present 

 in the amount of i c.c. of a five per cent suspension. The 

 alexin and the antialexin were in contact for thirty minutes 



1 This circumstance has been observed already by Bordet (I.e. p. 273). 



2 Morgenroth and Sachs: Berl. klin. Wochenschrift, No. 35 (1902). 



