

1905. } Chemistry of the Toxin-Antitoxin Reaction. 189 
attention to the fact that false equilibria were attained on the fractional 
addition of megatherium lysin to antilysin (experiments unpublished). 
On further investigation I found, however, that the nature of the 
equilibria obtained in partially neutralised and in neutral mixtures is not 
the same. This may be seen from the following experiments :— 
One c.c. of 0°625 per cent. antilysin was placed in each of two series of 
tubes. To one series 1 c.c. of various dilutions of lysin was added, and the 
mixture heated for two hours at 37°C. To the other series 0°5 cc. of 
the same dilution of lysin was added, and the mixtures heated for one hour 
at 37°C. Another similar addition of 0°5 cc. was then made, and the 
mixtures heated one hour at 37°C. Table V shows that the mixtures 








Table V. 
Addition at once. | Fractional addition. 
2 hrs. at 37°. Part I, 1 hr. at 37°. Part II, 1 hr. at 37°. 
Added to 1 c.c., 0°625 per cent. antilysin. Added to Part I. 
Lysin Saline Hem. Lysin Saline Lysin Saline Hem. 
in ¢.c¢. in ¢.¢. index. in ¢.¢. in ¢.¢. in €.¢. in ¢.¢. index 
- Or'l 0°9 18 °3 — — — — — 
- O'2 0°8 20°8 O°l 0-4 O°1 O°4 18 °3 
0°3 0°7 24 °6 —— — —- — — 
0°4 0°6 31°7 0-2 0°3 0°2 0°3 32 ‘1 
0°5 0°5 39 °2 — —— “= — — 
0°6 0 °4 48 ‘3 0°3 0:2 0°3 0°2 60 -O 
0°7 0°3 71°2 — — — — — 
0°8 0:2 91 °7 0-4 Ou 0 °4 0:1 100 
O'9 O°1 98 — — — — eX 
1:0 0:0 100 0°5 0-0 0°5 0:0 100 
which were made in this intermittent way have higher hemolytic indices 
than the mixtures which were made at one operation. The above was only 
found to be true when the resulting mixtures were strongly hemolytic. 
When, however, the mixtures contained considerably less free lysin, the 
hemolytic indices were the same in both series. From this and similar 
experiments, in which the volume of the antilysin was not appreciably 
modified by the addition of the lysin in concentrated form, it follows that 
false equilibria are attained in the lysin-antilysin reaction when the final 
concentration of the free lysin is high. In more nearly neutral mixtures 
