40

Scientific Memoirs by

injections had been administered the bird became absolutely motionless.
It remained standing for a short time and then sat down, still and watchful.
After sometime a tendency to permanent mandibular gaping manifested itself.
On the following day it remained sitting absolutely motionless, with the neck
retracted, the eyes open, and the back somewhat elevated. There were no
symptoms whatever resembling the specific symptoms of chronic intoxication
by cobra-venom. It remained in the same condition for the three next days,
and on the morning of the following one was found dead and rigid, still retain-
ing the same position.

     The results of these and similar experiments clearly demonstrated the
impossibility of inducing general convulsions and rapid death by means of
cumulative administration of the venom, and that in order to the occurrence
of such phenomena the latter must enter the system at once in certain
quantity and with a certain degree of concentration. With the most potent
samples of dried venom the introduction of 0.003 gramme sufficed certainly
to induce violent general convulsions and death when introduced simulta-
neously and in solution in 1 c. c. of water, but a like amount was powerless
to do so when in solution in 3 c. c. of water, and the same held good of
the cumulative introduction of much larger quantities by means of repeated
injections of fractional doses. The latter are capable of inducing phenomena
of local nervous irritation followed by symtoms of local nervous exhaustion, but
they fail either individually or cumulatively to give rise to any appreciable signs
of centric irritation. The condition of local nervous exhaustion following the
primary irritation in certain cases seems to be of a transitory nature, as in some
instances in which local muscular action entirely fails to make its appearance
in connection with injections of venom repeated at intervals of twenty minutes,
it will again begin to manifest itself if the period of the intervals be doubled.
The general phenomena attending the cumulative administration of normal
Daboia-venom in doses too small or too dilute to induce violent general convul-
sions and death within the course of a few minutes, are of precisely the same
nature as those attending the action of relatively large quantities of venom in
which the nerve-irritant toxin is deficient in amount or entirely absent, as
it frequently is in samples which have been kept for any length of time, and as
it certainly is, as Wall first pointed out,*in specimens which have been heated
to boiling. All evidences of direct centric nervous stimulation are absent and
are replaced by an excessive immobility and by indications of the occurrence
of blood-change, but of blood-change of a nature absolutely distinct from that
attending the action of cobra-venom, and manifesting itself in a great tendency
to the occurrence of sanguinolent effusions, and in a peculiar brick-red colour
and absence of coagulability in the blood when removed from the vessels.

*Op. cit.