90 
THE DESCENT OF MAN. 
Part I. 
of such feelings would be an unnatural monster. On 
the other hand, the desire to satisfy hunger, or any 
passion, such as vengeance, is in its nature temporary, 
and can for a time be fully satisfied. Nor is it easy, 
perhaps hardly possible, to call up with complete vivid- 
ness the feeling, for instance, of hunger ; nor indeed, as 
has often been remarked, of any suffering. The in- 
stinct of self-preservation is not felt except in the pre- 
sence of danger ; and many a coward has thought him- 
self brave until he has met his enemy face to face. 
The wish for another man’s property is perhaps as 
persistent a desire as any that can be named ; but even 
in this case the satisfaction of actual possession is gene- 
rally a weaker feeling than the desire : many a thief, if 
not an habitual one, after success has wondered why he 
stole some article. 
Thus, as man cannot prevent old impressions con- 
tinually repassing through his mind, he will be com- 
pelled to compare the weaker impressions of, for in- 
stance, past hunger, or of vengeance satisfied or danger 
avoided at the cost of other men, with the instinct of 
sympathy and good-will to his fellows, which is still pre- 
sent and ever in some degree active in his mind. He 
will then feel in his imagination that a stronger instinct 
has yielded to one which now seems comparatively 
weak; and then that sense of dissatisfaction will in- 
evitably be felt with which man is endowed, like every 
other animal, in order that his instincts may be obeyed. 
The case before given, of the swallow, affords an illus- 
tration, though of a reversed nature, of a temporary 
though for the time strongly persistent instinct con- 
quering another instinct which is usually dominant over 
all others. At the proper season these birds seem all 
day long to be impressed with the desire to migrate ; 
their habits change ; they become restless, are noisy. 
