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Scientific Memoirs by

give rise to any thing save local effects, and, hence, in so far as the lethal proper-
ties of the venom are concerned, it is of no practical importance.

     5. The phenomena attending the administration of sub-lethal doses so long
as these are capable of producing any appreciable effects, of minimal lethal
doses, and of excessive doses of cobra-venom are essentially alike, but in the case
of normal Daboia-venom this is not the case, as sub-lethal doses, where they
produce any appreciable effect, are followed by symptoms indicative of the
action of one toxic principle, and minimal lethal and excessive doses by symp-
toms indicative of that of another.

     6. In the phenomena normally attending the action of cobra-venom there
is no distinct evidence of the action of anything but a single toxin, whilst in the
case of Daboia-venom there is the most unequivocal evidence of the presence
of two distinct lethal toxins, one acting as a direct nervous irritant and the
other giving rise to septic changes in the blood.

     7. The toxin in cobra-venom acts cumulatively; in the case of Daboia-
venom the toxin which causes nervous irritation cannot act cumulatively whilst
that which induces septic phenomena does so.

     8. Dilution of minimal lethal doses of cobra-venom in no way affects
their potency, whilst dilution of minimal lethal doses of normal Daboia-venom
ordinarily renders them incapable of causing death because it renders the ner-
vous irritant toxin incapable of acting upon the nervous centres, whilst the
septic one, as a rule, is only lethal when it enters the system in relatively large
amounts.

     9. The symptoms attending the action of the septic factor in Daboia-venom,
although it is capable of acting cumulatively and is apparently unaffected by
dilution, are perfectly distinct from those attending the action of cobra-venom,
for, whilst in cases of intoxication by cobra-venom respiratory and nervous symp-
toms indicative of defective oxygen-supply constitute the characteristic pheno-
mena, in cases of chronic Daboia-poisoning such phenomena are entirely ab-
sent and are replaced by symptoms indicative of a tendency to abnormal escape
of blood-constituents from the blood-vascular system. Farther, in the case of
death from the action of cobra-venom the blood is characterised by its intense-
ly dark colour and by the fact that it coagulates rapidly and firmly unless ex-
cessive doses of venom have been directly introduced into the system, or life
has been artificially prolonged so as to give the ferment-action full time to
operate; whereas in the case of death from the action of Daboia-venom it is
of a peculiar dull brick-red colour and normally quite incoagulable, even when
death has been induced almost instantaneously by the direct intravenous injec-
tion of minimal lethal doses.

     There are certain points in connection with the action of Daboia-venom
which appear to merit special consideration. These are, first, the phenomena