Like so much of the diction in this chapter the phrase can be read in two senses:
first, as laughter without cause, as though Victor's heart is not in it; second, as
a cold, self-obsessed, or unfeeling discharge of nervous energy. Although the first
meaning is the natural way to construe the diction, the second remains behind, like
a sour aftertaste, to affect our later judgments. It is allied to the intimation of
madness expressed by the wildness of Victor's eyes.