Medical Officers of the Army of India.
1 1
the persistence of the reductive change are alike essentially affected both by
conditions of temperature and by the occurrence of putrefaction. The facts
that the mixtures of blood and venom were not invariably exposed to like condi-
tions of temperature ; that incipient putrefaction is opposed to the manifestation
of the toxic reduction ; and that the extent and kind of septic contamination
must necessarily have varied in individual instances, satisfactorily account for
the want of any precise uniformity of results throughout the entire series of ex-
periments.
Elevation of temperature accelerates the development of toxic reduction,
and, hence, mixtures of blood and venom of a given ratio exposed to relatively
high temperatures will show appreciable evidences of reduction at periods- at
which corresponding mixtures exposed to lower temperatures entirely fail to do
so. The differences which arise in this way are not dependent on any differences
in the quality of the venom, but are solely owing to the influence of external . con-
ditions, and, were it possible to acquire truly aseptic preparations, uniform
results might be obtained in the case of any given stock of venom, simply by
means of exposing mixtures of like ratio to like conditions of temperature and
noting the results at like times. But the matter is further complicated because,
as has been already pointed out, truly aseptic preparations of venom cannot be
obtained save by the use of means affecting both toxic property and capacity for
inducing solution, and we must, therefore, constantly allow for the occurrence
of effects induced by putrefactive change, the progress of which is influenced
not merely by conditions of temperature, but by the number and nature of septic
organisms present in individual instances. The occurrence of putrefaction, like
that of reductive change in the hæmoglobin, is accelerated by elevation in
temperature, but the rate at which it will progress at any given temperature must
also be influenced by the extent and nature of the septic contamination, and
consequently the mere exposure of mixtures of blood with like ratios of venom
of a given stock to like conditions of temperature during like periods will by no
means necessarily ensure like degrees of putrefaction in them. The earlier stages
of the putrefactive process in blood give rise to changes tending to mask the
reductive effects of cobra-venom on the respiratory property of hæmoglobin, and
it appears to be quite possible that, when septic contamination exceeds certain
limits and conditions otherwise favour the rapid incidence and progress of putre-
faction, any appreciable evidence of toxic reduction may fail to appear through-
out the entire course of an experiment. The reductive effects of the venom on any
portion of blood are only fully manifested in the absence of putrefaction, and, on
the onset of the latter, any reduction which may previously have been induced by
the venom undergoes a gradual diminution and is ultimately abolished. Owing to
this, mixtures of blood and venom, which at a certain time have shown unequivocal
evidences of reduction, may somewhat later entirely fail to do so, and the
precise period at which the evidence of toxic reduction is greatest will in any case