Medical Officers of the Army of India.
89
immediately antecedent dose. In consequence of this, when the doses came to
be of more than sublethal amount, each increment of venom, although incap
-
able of causing death, was for some time followed by the appearance of
general symptoms of intoxication, and it was evident that, with a slight increase
in the amount of the increment, fatal intoxication must have followed. It
would appear, then, that there is a definite direct relation between the amount
of venom which enters the system and the activity of the reactive systemic
manufacture of antivenene, and that the amount of the latter which is manu
-
factured is not greatly in excess of that requisite, to neutralise the toxic effect
of the amount of venom which acts as the stimulant to the manufacture. It is,
no doubt, true that, during the latter portion of the course of the experiment,
increments in the amount of venom, which had previously sufficed to give rise
to appreciable effects, ceased to do so, but this may have been simply owing to
the fact that in this case the increments of venom remained constant, whilst the
total production of antivenene, being directly proportionate to the total amount
of venom administered at any one time, underwent a progressive increase, so
that increments which at first bore a high ratio to the amount of available
antivenene ultimately came to hold a much lower one, and so ceased to give
rise to the same effect which they were primarily capable of inducing. Be
that as it may, however, the phenomena at all events afford no positive evidence
that the reactive manufacture of antivenene is at any time carried on to such
an extent as to provide for the presence of any great surplus of the antidote
in the blood beyond the amount which is necessary to equilibrate the toxic action
of any given bulk of venom against which an immunity has gradually been
established.
The second noteworthy point is that, in the termination of the experiment
we have conclusive evidence of the fact that the immunity which can be estab
-
lished against the action of daboia-venom by means of habitual cumulative
treatment does not imply the presence of any corresponding immunity against
that of cobra-venom. In this case an apparently complete immunity against
the action of four times a minimal lethal dose of daboia-venom afforded no pro
-
tection whatever against a slightly supra-minimal lethal dose of cobra-venom.
But the immunity against the daboia-venom must presumably have been depend
-
ent on the presence of a material of the nature of antivenene, so that the evi
-
dence goes to prove that, just as cobrine antivenene has been already shown to
be powerless in cases in which daboia-venom has entered the system, the cor
-
responding daboia antivenene is powerless where cobra-venom has done so.
The normal toxic effects produced under the influence of colubrine and viperine
poisons are certainly quite distinct in character, and the antivenenes which are
coincidently developed within the system appear to be equally so.
Experiment VI. —A large, healthy goat, received a subcutaneous injection
of 0.005 gramme of dried daboia-venom in 0.5 C. C. of water, in one hind leg, N