184 Mr, J. A. Craw. On the Physical [Mar. 22, 
The hemolytic power of the residues and the gelatine could be demonstrated 
to be due to free megatherium lysin, for on the addition of sufficient antilysin 
the hemolytic power was in all cases entirely neutralised. For example, | c.c. 
of residue No. 1 of index (38°6) with 1 c.c. of 5-per-cent. antilysin, added 
directly to the test blood, gave a hemolytic index of (84), the same mixture 
heated for one hour at 37° C. before adding to the test blood, gave as index 
(1:8). Again, 0°5 cc. of gelatine from No. 1 caused complete hemolysis 
(index 100), whereas, after being heated for 1 hour at 37° C. with 1 cc. of 
5-per-cent. antilysin the value was reduced to (25). Free lysin, then, exists in 
the residues, and since the filtration was completed in less than two hours at 
a temperature of 10° C., at which temperature the velocity of reaction is 
extremely low, there can have been no appreciable liberation or dissociation of 
lysin during the filtration. It follows, therefore, that free lysin exists in 
neutral and highly over-neutralised mixtures of lysin with antilysin, and that 
the free lysin is partially removed during filtration. 
The Existence of Free Antilysin in Partially neutralised and Neutral 
Mixtures. 
The residual fluids from Experiments 1 to 6 showed slightly smaller 
hemolytic indices after standing over night at 10° C., and on heating them 
to 37° C. for 1 hour their hemolytic powers further markedly decreased. 
This is clearly shown by the following experiment :— 
1 cc. of residue No. 1 (index 38°6) together with 1 cc. of saline, when 
added directly to the test blood, gave a hemolytic index of (35), whereas the 
same mixture heated for one hour at 37° C. before being added to the test 
blood, gave an index of only (23°4). This behaviour indicates that in Nos. 5 
and 6, the filtration which causes an increase in the concentration of any free 
lysin or antilysin by the withdrawal of water, occasions a further reaction which 
has a low velocity at 10° C., but is considerably more rapid at 37°C. As this 
phenomenon is common to all the residues it follows that if the above 
interpretation be correct, free antilysin is present in all cases, and 
presumably must have been present in the original mixtures. Nos. 1, 2, and 
3 were, however, hemolytic mixtures, and No. 4 neutral, which points to the 
conclusion that free antilysin exists in partially neutralised and neutral mixtures 
as well as in over-neutralised mixtures. 
This conclusion is strengthened by the high neutralising power possessed 
by the original mixture and by the residue of No. 3, when fresh lysin was 
added, as shown by the following experiments :— 
To one series of tubes containing 1 cc. of the original hemolytic mixture 
