112 LECTURES ON IMMUNITY 



maleinic, 0.013; an( i citric acid, 0.012. These figures do not 

 differ very much from each other; they are really a little 

 higher for the weaker than for the stronger acids, perhaps 

 indicating a slightly marked hydrolytic effect. But on the 

 whole they indicate a combination, although of not quite so 

 strong a nature as with the bases. For very long times of 

 reaction we therefore observe no real velocity of reaction, 

 but a binding, and hence we might expect that for these 

 long times of reaction the values of /* converge to zero. 

 This convergence takes place much earlier for the strong 

 acids and bases, which react more rapidly, than for the 

 weak ones. Thus, for instance, a dosage of o.i c.c. normal 

 NH 3 needs 210 minutes to yield the same haemolytic effect 

 that the equivalent quantity of the three strong bases exam- 

 ined give in 15 minutes (at 16.2); and an addition of 0.05 

 c.c. of dichloracetic acid produces the same hasmolytic 

 effect in 5 minutes as the equivalent quantity of acetic acid 

 in 60 minutes. Therefore even the shortest time (10 

 minutes) used in these investigations of strong acids or 

 bases seems to be much too long to give a value, ft , for ft, 

 which approaches that for an infinitely short time, corre- 

 sponding to the real value for the velocity of reaction. On 

 the other hand, the values for the shortest times for weak 

 acids do not differ much from each other, and probably 

 also not from the theoretical limit-value, which seems to 

 be about p= 27,000. A little higher, perhaps, lies the true 

 limit-value for ammonia, p= 29,000. These limit-values are 

 probably valid even for the other acids and bases. The 

 great difference in the speed of reaction between the strong 

 and the weak bases and acids seems to indicate that we 

 have even here to do with an ionic reaction, although the 



