There is in man a specific lust for cruelty which infects even his
passion of pity and makes it savage. Simple disgust at cruelty is very
rare. The people who turn sick and faint and those who gloat are
often alike in the pains they take to witness executions, floggings,
operations or any other exhibitions of suffering, especially those
involving bloodshed, blows, and laceration. A craze for cruelty can
be developed just as a craze for drink can; and nobody who attempts to
ignore cruelty as a possible factor in the attraction of vivisection and
even of antivivisection, or in the credulity with which we accept its
excuses, can be regarded as a scientific investigator of it. Those who
accuse vivisectors of indulging the well-known passion of cruelty
under the cloak of research are therefore putting forward a strictly
scientific psychological hypothesis, which is also simple, human,
obvious, and probable. It may be as wounding to the personal vanity of
the vivisector as Darwin's Origin of Species was to the people who
could not bear to think that they were cousins to the monkeys (remember
Goldsmith's anger when he was told that he could not move his upper
jaw); but science has to consider only the truth of the hypothesis,
and not whether conceited people will like it or not. In vain do the
sentimental champions of vivisection declare themselves the most humane
of men, inflicting suffering only to relieve it, scrupulous in the use
of anesthetics, and void of all passion except the passion of pity for
a disease-ridden world. The really scientific investigator answers that
the question cannot be settled by hysterical protestations, and that if
the vivisectionist rejects deductive reasoning, he had better clear his
character by his own favorite method of experiment.