first. In both Macbeth and Lady Macbeth the germ of crime
was latent; they wanted only favourable circumstances to convert
them into one of those criminal couples who are the more
dangerous for the fact that the temptation to crime has come to
each spontaneously and grown and been fostered by mutual
understanding, an elective affinity for evil. Such couples are
frequent in the history of crime. Eyraud and Bompard, Mr. and
Mrs. Manning, Burke and Hare, the Peltzer brothers, Barre and
Lebiez, are instances of those collaborations in crime which find
their counterpart in history, literature, drama and business.
Antoninus and Aurelius, Ferdinand and Isabella, the De Goncourt
brothers, Besant and Rice, Gilbert and Sullivan, Swan and Edgar
leap to the memory.


[3] "Le Crime a Deux," by Scipio Sighele (translated from the
Italian), Lyons, 1893.

In the cases of Eyraud and Bompard, both man and woman are idle,
vicious criminals by instinct. They come together, lead an
abandoned life, sinking lower and lower in moral degradation. In
the hour of need, crime presents itself as a simple expedient for
which neither of them has any natural aversion. The repugnance
to evil, if they ever felt it, has long since disappeared from
their natures. The man is serious, the woman frivolous, but the
criminal tendency in both cases is the same; each performs his or
her part in the crime with characteristic aptitude. Mrs. Manning
was a creature of much firmer character than her husband, a woman
of strong passions, a redoubtable murderess. Without her
dominating force Manning might never have committed murder. But