VENOM OF THE AUSTRALIAN BLACK SNAKE. 153 
does not pass through the filter, whereas the other proteid does. 
The filtrate is still highly poisonous, but a whole group of symptoms 
which are characteristic of the venom, are absent, as was found 
to be the case after heating to 82° C. 
This fact is illustrated by the following six experiments :— 
Experiment 1—0-05 gramme of Pseudechis venom was dissolved 
in 50 ce. of 0-9% NaCl solution. 10 cc. were kept for comparative 
experiment, and 40 cc. passed through the filter. 
10 ce. of the filtered and 10 cc. of the unfiltered solution of 
venom were both faintly acidified and boiled. The unfiltered 
solution of venom gave cloudiness which settled as a precipitate ; 
the filtered venom remained absolutely bright and clear. Filtering 
through gelatin had kept back the coagulable proteid. 
I then tried whether the filtration had also deprived the venom 
of its capacity of destroying dogs’ red blood corpuscles in vitro. 
Experiment 2—Four slides were prepared. On two a drop of 
Mond teens 4a og was mixed with an equal volume of 0°97 NaCl 
solution. On two others a drop of blood was mixed with a drop 
of the solution of filtered venom.! All four slides were ringed 
round with acid-free oil to avoid concentration, and left at the 
laboratory temperature 12°C. By next day (twenty-four hours) 
no difference was to be observed between the venom slides and 
the control slides, 
Experiment 3—Four other slides were prepared as before, two 
with isotonic salt solution alone, and two with the same salt 
solution containing 0-01 % venom. In this experiment the slides 
were kept at 37°C. Next day no difference could be detected 
between the four slides. 
As under the same circumstances a similar solution of unfiltered 
venom would have broken up the majority of the corpuscles, : 
Conclude that the active agent in this regard is sepa meet 
filtration through gelatin. 
1 This was a 0-99, NaCl solution containing 0°1% of venom. _ 
