THE COMPOUND H^MOLYSINS 



was true except when the quantity a was very low. To 

 explain this very different behaviour in different cases the 

 authors have made use of rather complicated hypotheses, 

 to enter in detail upon which would consume too much 

 space. These experiments were the first quantitative 

 measurements, on a large scale, bearing upon the action 

 of compound haemolysins, and they therefore merit a 

 certain interest. 



Another observation of quantitative nature was made by 

 Morgenroth. 1 He determined the least quantity of alexin 

 that had to be added to produce complete haemolysis, and 

 the greatest quantity of alexin which could be added before 

 a perceptible haemolysis occurred. In this case immune- 

 body was present in excess. In other cases alexin was 

 present in excess, and the quantities of immune-body 

 necessary for complete haemolysis and for the first trace 

 of haemolysis were observed. Morgenroth found that the 

 two said quantities of alexin were, as the average of 13 

 combinations, in the proportion 100 to 13.6; and the cor- 

 responding quantities of immune-body in the proportion 

 100 to 14.1 (mean of 10 combinations). If, as is rather 

 probable, the quantity of haemolysin found is nearly pro- 

 portional to the quantities of alexin or of immune-body 

 used, and the rule holds that the degree of haemolysis is 

 proportional to the square of acting haemolysin, this would 

 indicate that an haemolysis of 2 per cent is just perceptible, 

 which in some cases may be rather probable. 



Quite recently Wilfred H. Manwaring 2 has given a 



1 Morgenroth : Wiener klin. Wochenschrift, No. 5 (1904). 

 ' 2 Manwaring: Journ. Biol. Chemistry, 1. 213 (1906). No definite indi- 

 cation is given of the nature of the preparations employed. 



