338 The Naturalist in La Plata. 
ia the herd that he may be buffeted with impunity by 
all, even by those that have hitherto suffered buffets 
but have given none. But judging from my own 
observation, this persecution is not, as a_ rule, 
severe, and is seldom fatal. 
It is often the case that a sick or injured animal 
withdraws and hides himself from the herd; the 
instinct of the “ stricken deer” this might be called. 
But I do not think that we need assume that the 
ailing individual goes away to escape the danger of 
being ill-used by his companions. He is sick and 
drooping and consequently unfit to be with the 
healthy and vigorous; that is the simplest and 
probably the true explanation of his action ; although 
in some cases he might be driven from them by 
persistent rough usage. However peaceably gre- 
garious mammals may live together, and however 
fond of each other’s company they may be, they do 
not, as a rule, treat each other gently. Further- 
more, their games are exceedingly rough and require 
that they shall be in a vigorous state of health to 
escape injury. Horned animals have no buttons to 
the sharp weapons they prod and strike each other 
with im a sportive spirit. I have often witnessed 
the games of wild and half-wild horses with astonish- 
ment; for it seemed that broken bones must result 
from the sounding kicks they freely bestowed on one 
another. This roughness itself would be a sufficient 
cause for the action of the individual, sick and out 
of tune and untouched by the glad contagion of the 
others, in escaping from them; and to leave them 
would be to its advantage (and to that of the race) 
since, if not fatally injured or sick unto death, its 
