3

of other species, this hypothesis of Martin would receive its death blow. We
shall return to this question later on.

        With this introduction we may now pass on to examine the data which bear
on the question under consideration.

        In a recent paper⁹ on the serum therapy of snake bite Dr. Tidswell of Sydney
has correctly pointed out that Calmette's serum, inasmuch as it is prepared with
a mixture of snake venoms, in which mixture, however, cobra venom greatly
preponderates, is not strictly adapted for the settlement of specificity, and that
it was necessary for this purpose to possess a serum prepared with one single
kind of venom and to test its efficacy against the same and other kinds of venom.
In this same paper he gives some most interesting results which he obtained
working with the serum of a horse immunised with the pure venom of the
Australian tiger snake (Hoplocephalus curtus). He showed that 0.4. c.c. of
this serum was sufficient to neutralise ten lethal doses, viz., 0.00059 grammes, for
the rabbit of the particular venom used to immunise the horse. He further
showed that this same serum failed completely to neutralise the poisons of the
brown and black snakes and also that of the death adder. The outcome, in
short, of Tidswell's observations " is such as to indicate that the serum is
specific in its action, operative only against the venom by means of which it
is prepared."

        The observations which I have now to put forward further extend my
original observations, mentioned above, made with Calmette's serum and cobra
and daboia venoms. They, also, further extend the observations made by Tidswell
with the serum prepared with the poison of Hoplocephalus curtus. It is un-
necessary here to reprint the details ¹⁰ of the experiments made with Calmette's
serum and cobra and daboia poisons. It will be sufficient to recall the main
facts demonstrated by these experiments, viz., that the serum sent out
from the laboratory at Lille was able to neutralise, to a certain extent, the
venom of the cobra, but was quite inactive against the venom of Daboia
Russellii.

        The direction in which these observations were now extended was to test
Calmette^'s serum with the venoms of two other species of Indian snakes, viz.,
Bungarus fasciatus and Echis carinata. Bungarus fasciatus is a snake belonging
to the genus Bungarus, closely allied to the genus Naia, of which the cobra is
a species. It is interesting in this connection to note that the genus Naia and
the genus Bungarus belong to the same sub-family of Colubridae, viz., Elapinæ,
in which sub-family, also, naturalists classify the bulk of the ophidian fauna of
Australia. Further, all the members of the sub-family Elapinæ are poisonous.
Echis carinata belongs to the genus Echis, a genus closely allied to the genus
Vipera, of which genus Daboia Russellii is a species. The genus Echis and the
genus Vipera belong to the same sub-family of Viperid, viz., Viperinæ.

        Let us first consider the experiments made with Calmette's serum and the
venom of Bungarus fasciatus. As a preliminary measure it was necessary to