For love, thou know'st, is full of jealousy.
--_Shakspere_.
Jealousy may exist apart from sexual love, but there can be no such
love without jealousy, potential at any rate, for in the absence of
provocation it need never manifest itself. Of all the ingredients of
love it is the most savage and selfish, as commonly witnessed, and we
should therefore expect it to be present at all stages of this
passion, including the lowest. Is this the case? The answer depends
entirely upon what we mean by jealousy. Giraud-Teulon and Le Bon have
held--as did Rousseau long before them--that this passion is unknown
among almost all uncivilized peoples, whereas the latest writer on the
subject, Westermarck, tries to prove (117) that "jealousy is
universally prevalent in the human race at the present day" and that
"it is impossible to believe that there ever was a time when man was
devoid of that powerful feeling." It seems strange that doctors should
disagree so radically on what seems so simple a question; but we shall
see that the question is far from being simple, and that the dispute
arose from that old source of confusion, the use of one word for
several entirely different things.