21
prevent clotting of both citrate and oxalate plasma, I next proceeded to estimate
the amount of venom which was able to effect this, when added to the plasma
2 hours before the addition of the quantity of lime solution sufficient to cause
clotting of the control in a few minutes.
The results of these estimations are detailed in Tables XVII and XVIII of
the protocols. In the case of citrate plasma (Table XVII) it was found that
I milligramme of cobra venom was sufficient to keep 2 c.c. of plasma perma-
nently liquid, and that amounts less than this, down to 0 ' 2 milligramme, had
a very marked inhibitory action on coagulation, the clot which had formed
after 20 hours being always soft and loose. The control, with the same amount
of lime as the venom tubes, clotted solidly in a few minutes. The similarity
between this result and that detailed in Table VII, the series of experiments in
which citrate whole blood was used, allowance being made for the plasma being
double the amount of the whole blood, is striking and worthy of note. In the case
of oxalate plasma (Table XVIII) it was found that even 0.2 milligramme of cobra
venom was able to keep 2 c. c. of plasma unclotted for a period of at least
20 hours. The control, with the same quantity of lime added, clotted solidly in
10 minutes. The se results, then, confirm and further extend the observations
with citrate whole blood, which I have already recorded. They show that the
h æ m o l y t i c a c t i o n o f c o b r a v e n o m i s q u i t e i n d e p e n d e n t o f i t s a c t i o n i n i n h i b i t i n g
coagulation, that, in fact, the action which this poison has on the blood coagula-
bility does not depend on the destructive effect which it has on the red blood
corpuscles and other cells. It would, therefore, appear certain that the action
of one venom at any rate, namely, cobra venom, on the blood coagulation in
vivo cannot be explained by Martin's hypothesis, that is to say, the setting
free of nucleo-proteids as a result of the great destruction of the cells of
the body in general, and of the red cells in particular, which is caused by this
poison. It cannot, however, be said from these experiments that nucleo-proteids
play no part in this phenomenon, as plasma prepared in the manner I
have described is rich in these substances, derived, as they are, from disintegra-
tion of the white cells of the blood after its withdrawal from the vessels.
With the view of further investigating this action of cobra venom, two
series of experiments were made with a sample of hydrocele fluid. This sample
did not clot on the addition of a soluble lime salt, but was clotted solidly by the
addition, either with or without a small amount of lime, of a small quantity of
citrate donkey plasma (I per cent.). It was found that o.I c.c. of this plasma
clotted 2 c.c. of hydrocele fluid in about 20 minutes. A reference to Tables XIX
and XX of the protocols will show that even 0.1 milligramme of cobra venom was
sufficient to inhibit completely the clotting of this sample of hydrocele fluid, as
brought about by the addition of a small amount of citrate plasma, when the
venom was allowed to act on the plasma for Io minutes before the addition
A D V O C A T E S L I B R A R Y