96 WILD NEIGHBORS CHAP. 111 
quills of the tail of the European porcupine, under 
circumstances of alarm, is another interesting fact 
discussed in Chapter VII. 
But the large part the tail plays in the expres- 
sion of brute emotions, from furious anger to 
extravagant joy, is familiar to most persons and 
need not be dwelt upon here. Mr. Darwin has 
treated of it extensively in his capital book “The 
Expression of the Emotions.” Foxes, wolves, 
jackals, et 7d omne genus, exhibit excitement and 
alarm by elevating or depressing their brushes, 
and no doubt wag them in welcome to their 
friends. The nervous organization and moral sen- 
sitiveness of dogs have been greatly enhanced by 
their long association with man, and domestic 
dogs have many more emotions to express, no 
doubt, than their wild, or semi-wild, congeners. 
I have been struck by the lack of affectionate 
demonstrativeness among the yelping and often 
savage dogs about an Indian camp. It was rare 
that any of them were made pets of, and they had 
never been led to show that welcome and grati- 
tude and joy which are so plainly expressed by 
the flexible tails of the terriers, and poodles, and 
collies of our houses. 
