Scientific Memoirs by
septicæmia, or other accidental causes. No post-mortem examination appears
to have been made.
Thus, in regard to neither of these three cases is there evidence to show that
the fatal event was due to the venom. On the contrary, the likelihood that
death resulted from other and accidental causes is so great that these three
experiments may well be eliminated from the series; and when so eliminated,
there remain 20 experiments, with no deaths.
Mitchell records 1 seven experiments on rattlesnakes with rattlesnake
venom, and concludes that "the above experiments
were on the whole so definite in their results that I
did not think it necessary to multiply them," and that these rattlesnakes "really
died from the venom."
An examination, however, of the details of his experiments renders it difficult
to conceive how Dr. Mitchell was led to such a conclusion.
But before examining the particulars of these experiments seriatim, it
is necessary to remember, firstly, that these snakes had been for some time in
captivity—the record of these experiments being prefaced by the remark "at
the close of a series of experiments on warm-blooded (animals) I made use of
some of my largest snakes in the following manner."1 And, secondly, that these
snakes appear to have been repeatedly subjected to extremely rough handling
and forcible compression of the poison-glands during extraction of the venom—a
process so severe that it is noted, 2 "One snake in every four died within two to
five days" from the mere effects of the process for extracting their venom. And
to this process the snakes of Experiments I, III, V, VI and VII, seem to have
been subjected during their final experiment.
In Experiment I, the snake did not die till the fourteenth day after being
bitten, and it presented no signs of viper-poisoning. 3 In Experiment II, the
snake "died on the fourteenth day. The wound was apparently healthy.". . . "The
blood was uncoagulated, but there was no other visible lesion of any internal
organ." Concerning Experiment III, it is noted, "In all probability this serpent
died from some other cause than venom-poisoning." In Experiment IV the snake
"recovered," although it bit itself three times on a part from which skin had been
removed, throwing out "a good deal of venom which was thrust deeply into the
muscles of wounded part." "No blood was effused" and "at the close of two
weeks this snake was healthy and bit eagerly." In Experiment V, although the
snake lived for 36 hours after injection of poison, there appears to have been no
extravasation of blood, except that the stomach "contained bloody mucus."
The wound "was not stained with blood." "The heart was full of clotted
blood." In Experiment VI, where the snake lived for about three days, it is
recorded that the local appearances were even "less extensive" than in last
1 l o c . c i t . ,
p . 6 1
e t s e q .
2 idem, p. 29, the author remarking that "it is not impossible that too severe a compression of the
venom-gland may produce rupture of its substance and consequent blood-poisoning."
3 Fluidity of blood with bloody extravasations are the leading physical signs of viper-poisoning.
Mitchell's experiments on rattle
-snakes versus rattlesnakes.