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Scientific Memoirs by
The data contained in Table VII very clearly illustrate the influence which,
as has been recorded by Wall and other observers, elevation of temperature has
in occasioning the progressive reduction and final abolition of toxic property
in cobra-venom. Even momentary boiling occasions a diminution in toxic potency
sufficing to reduce minimal and slightly supraminimal doses to subminimal
ones ; a longer exposure to heat reduces the potency of larger doses to such an
extent as to appreciably retard their lethal action; and prolonged exposure serves
to render even excessively large doses quite innocuous. But, as Table VIII
shows, a parallel series of phenomena present themselves in connection with the
capacity for giving rise to hæmatic change. Brief boiling gives rise to dimi-
nution and prolonged boiling to abolition of both the toxic and specific solvent
properties of cobra-venom, and this coincidence of itself is enough to suggest the
existence of a very close relation between the occurrence of the hæmatic
changes and the development of intoxication. It is, of course, possible that this
simultaneous loss of two distinct properties may be a mere matter of coincidence,
but, when the phenomenon is taken along with that of the variation of liability
to hæmatic change which accompanies variation in degree of susceptibility to
intoxication, it appears to be more logical to regard it as indicative of the
existence of a causal relation and to explain the loss of lethal power in the
venom as the consequence of its loss of power to give rise to hæmatic change.
There can be no question of the facts that cobra-venom has a specific
power of inducing important changes in the structural and functional properties
of the blood of animals susceptible to its intoxicant effects ; that variations in sus-
ceptibility to intoxication run parallel with variations in the degree to which the
blood is liable to undergo change under the influence of contact with the venom,
and that both the lethal potency and the capacity for inducing change are
alike affected by exposure to high temperatures. They in themselves afford
very strong evidence in support of the belief that the primary action of cobra-
venom in giving rise to intoxication is one affecting the blood, and the close
parallelism of the phenomena presenting themselves in cases of cobrine intoxi-
cation with those characteristic of morbid conditions unequivocally dependent
on alterations in the quantity or quality of the blood renders the proof almost
complete. The phenomena in cases of intoxication by carbonic oxide and those
attending excessive hæmorrhage are clearly primarily dependent on the fact
that the blood no longer fairly satisfies the demands, and specially the respiratory
demands of the system, and, when we find parallel symptoms arising under the
influence of a material which is unequivocally capable of giving rise to the
occurrence of important structural and functional hæmatic changes, it is surely
more reasonable to ascribe them to the presence of the latter than to credit
them to any obscure, direct action simultaneously exerted upon the nervous
apparatus. When we have the clearest evidence that cobra-venom has the