1^2 LECTURES ON IMMUNITY 



bases), probably because the process goes on with insen- 

 sible velocity. 



For stronger concentrations of the haemolysins total 

 haemolysis occurs if they are permitted to act through a 

 long enough time. If the time of action be restricted (as 

 by centrifugation), it is possible to follow the development 

 of the reaction, as has been said above (cf. p. 100). 



The presence of salt J exerts a strong retardative influ- 

 ence upon the hasmolytic power of the alkalies. Probably 

 this effect depends on a diminution of the velocity of re- 

 action. Especially is this true for the influence of ammo- 

 niacal salts upon ammonia. The different salts of the 

 strong bases (KOH, NaOH, and LiOH) are of the same 

 degree of efficacy in equivalent concentrations; the effect 

 is nearly proportional to the cube root of the concentra- 

 tion ; 0.02 n. salt solution lowers the effect in the propor- 

 tions i : 0.4. The salts of ammonia also seem to be very 

 similar to each other in this regard : 0.004 n - NH 3 salt 

 lowers the effect in the proportion 1:0.7; o.oi6n. in the 

 proportion 1:0.25 ; and 0.06 n. in the proportion 1:0.14. 



On the other hand, it is perfectly clear that the addition 

 of the equivalent quantity of hydrochloric acid to a solu- 

 tion of sodium hydrate would completely suspend its hae- 

 molytic power, since in this reaction sodium chloride is 

 formed, which has no haemolytic effect. Of a sodium 

 hydrate solution (neutralised to 50 per cent) it would be 

 necessary to add the double quantity (a slight correction 

 should be introduced for the lowering influence of the 

 salt, and for the quantity of alkali bound that gives no 

 action) to attain the same haemolytic effect. We then say 



1 In this case the physiological solution is made of cane sugar. 



