THE COMPOUND ILEMOLYSINS 22? 



solution, b cannot diffuse into the cells during the given 

 time of the experiment and produce a lysis, whereas a is 

 present there in many times the necessary quantity. If 

 a decreases, but not so much so that the quantity necessary 

 for the lytic action is not absorbed by the cells, then b 

 increases in the surrounding fluid and a greater quantity 

 of it diffuses into the cells within a given time. There- 

 fore the quantity of ab present in the cells may increase 

 with decreasing quantity of a, if this substance be present 

 in great excess in the surrounding fluid. The presence of 

 a maximum is therefore quite easy to understand. The 

 very great flatness of the curve of this maximum indicates 

 that the haemolysin ab is stable only in the presence of a 

 large excess of a and b\ and that a binding of strong 

 affinities with sharp discontinuities, as Ehrlich supposes, 

 is excluded. Our view leads furthermore to the conclu- 

 sion that the effect observed by Neisser and Wechsberg 

 should be more prominent for low values of b than for 

 larger values. The quantity of diffusing free alexin is in 

 the first approximation proportional to b. This quantity 

 is therefore proportional also to the quantity of haemolysin 

 formed in the given time of action (two hours at 37 C. 

 and the time of sedimentation at lower temperature, 

 about 3 C.). With large quantities of alexin (b>2O in 

 the present case), the diffusion transports enough of 

 alexin during the time of action to cause total haemolysis, 

 even at the highest concentrations of a employed. 

 Further, it is evident that as the quantity of free 

 alexin is nearly proportional to b and inversely propor- 

 tional to a, nearly the same effect will be reached if - is a 



a 



