12
Scientific
Memoirs by
be determined, not merely by the temperature to which the mixture of blood
and venom has been exposed, but by the extent to which it was originally septi-
cally contaminated and the nature of the septic organisms constituting the
contamination.
Elevation of temperature within certain limits unequivocally favours the occur-
rence of the toxic reduction, but it also accelerates putrefactive change, and,
under these circumstances, the antagonism of the two processes must have led
to even greater confusion than is actually likely to arise, had it not been that
conditions of temperature are apparently more influential in affecting the pro-
gress of putrefaction than that of toxic reduction. In consequence of this, at rela-
tively low temperatures, the process of reduction tends to outstrip that of putre-
faction and the full effects of the reductive action of the venom have time to mani-
fest themselves before those of incipient putrefaction come into play to mask them.
Owing to the antagonistic actions of the toxin and of septic contaminations and
to the relations of toxic reduction and putrefactive change to conditions of tem-
perature, mixtures of blood and venom exposed to relatively low temperatures
afford clearer evidences of the occurrence of toxic reduction than corresponding
mixtures exposed to higher temperatures are likely to show, and, where extensive
septic contamination and relatively high temperatures co-exist, there may even be
little or no appreciable evidence of toxic reduction at any time, Taking these
facts into consideration, it is clear that any exact uniformity in the nature of the
results of the experiments embodied in the Table cannot reasonably be looked
for, and that the data as they stand are really indicative of the presence of a
specific reductive action in the venom on the respiratory property of hæmo-
globin, and of the fact that the onset of putrefaction gives rise to changes tending
to neutralise and finally abolish toxic reduction. Whether or how far the
phenomenon of recovery of respiratory property is dependent on decomposition
of certain constituents of the venom remains, however, in the meantime a matter
of conjecture.
The facts that the progress of the toxic reduction is affected by conditions
of temperature, and its persistence determined by the absence of putrefactive
change, appear to afford a satisfactory explanation why certain competent
observers, such as Mr. Pedler,* should have failed to detect its presence, for, at
low temperatures, their examinations may readily have been undertaken at
periods before any appreciable reduction had been effected, and, at high ones, at
times at which all evidences of reduction had already been obscured or even totally
abolished owing to the incidence of putrefaction.
The actions of cobra-venom and of putrefactive change in giving rise to
reduction and recovery of respiratory property in mixtures of blood and venom
exposed to different thermic conditions are illustrated in Figs. 5,7, 8 and 9 of Plate
II. Fig. 5 shows the phenomena of respiratory property exhibited by 10.5 c.c. of
* Report of the Indian Commission for the investigation of snake poisons.