ADAPTATION FOR THE INDIVIDUAL 117 
may be safe. One of these, which is doubtless often 
quite effective and may serve to save an animal’s life, 
is that of being able to emit an odor so nauseating as 
to offend the enemy’s sense of smell, and doubtless 
remove the keen edge of his appetite. It is not un- 
common among the group of insects properly known 
as bugs to possess an exceedingly unpleasant odor. 
Anyone who has handled a squash bug will know ex- 
actly what I mean, and there are other members of 
the group not so common as the squash bug, which, 
at least to the human nose, are distinctly offensive. 
Some of the beetles also save themselves by this de- 
vice. 
One of the most interesting developments of this 
peculiarity is found in the case of the common skunk. 
This creature has in each groin a gland capable of se- 
creting a highly offensive fluid. Ordinarily this 
liquid is kept safely within its sac, and for a long time 
none of it may escape. When closely cornered, the 
- skunk will turn its tail toward the enemy and with 
a quiver and a flip of his tail it can guide the openings 
of two little tubes that come out along the root of the 
tail in such fashion as to eject the fluid in a fine and 
foul-smelling stream against the animal from which 
the skunk would escape. Once fairly hit by this fluid, 
I imagine most animals will drop the skunk. A dog 
surely will, and will hate himself for having made 
