U PROPERTIES OF H^MOLYTIC SERA 



the complement becoming fixed to the sensitized corpuscles 

 before there has been time for the immune-body to pass to 

 the fresh corpuscles. The result, of course, also shows that 

 the combination of complement is a firm one, and that dis- 

 sociation of it does not take place under the conditions 

 mentioned. Morgenroth assumed that the complement 

 locked up the molecules of immune-body in the red cor- 

 puscles, but did not experimentally prove that this was the 

 case. The subject will be referred to again below (p. 34). 



As the relation of time to the firmness of union of an 

 anti-substance with its antigen has been considered to be 

 of importance, I have performed experiments to determine 

 whether the dissociability of immune-body from red cor- 

 puscles becomes less marked in course of time. The amounts 

 of immune-body which can be separated from red corpuscles 

 after one hour and after twenty-four hours have been 

 compared. In the latter case the given number of doses 

 of immune-body are added to the corpuscles and they are 

 allowed to remain at the room temperature for twenty-four 

 hours (it may be noted that the total amount of immune- 

 body capable of combination is taken up in about half an 

 hour). The tubes are then centrifugalized, and the cor- 

 puscles are washed in salt solution and re-suspended ; the 

 untreated corpuscles are then added and the experiment 

 is carried out as above described. The 1-hour tubes are 

 similarly treated at the same time. The result is that as 

 much immune-body can be obtained by dissociation from 

 the 24-hour tubes as from the 1-hour tubes ; that is, there 

 is no evidence of increasing firmness of the union of immune- 

 body in course of time. 



The facts with regard to dissociation of immune-body 

 from the corresponding receptors of red corpuscles are 

 of interest in connexion with the results obtained by inject- 

 ing red corpuscles saturated with immune-body. If the 

 molecules which act as antigens are the same as the receptors 



