336 The Naturalist in La Plata. 
to move or rest, and to act at all times harmoniously 
together, as if controlled and guided by an extrane- 
ous force. I may mention that the kindly instinct 
im animals, which is almost universal between male 
and female in the vertebrates, is most apparent in 
these harmoniously acting birds. Thus, in ha 
Plata, I have remarked, in more than one species, 
that a lame or sick individual, unable to keep pace 
with the flock and find its food, has not only been 
waited for, but in some cases some of the flock 
have constantly attended it, keeping close to it 
both when flying and on the ground; and, I have 
no doubt, feeding it just as they would have fed 
their young. 
Naturally among such kinds no one member is of 
more consideration than another. But among mam- 
mals such equality and harmonyis rare. The instinct 
of one and all is to lord it over the others, with the 
result that one more powerful or domineering gets 
the mastery, to keep it thereafter as long as he can. 
The lower animals are, in this respect, very much 
lke us; and in all kinds that are at all fierce- 
tempered the mastery of one over all, and of a few 
under him over the others, is most salutary; 
indeed, it 1s inconceivable that they should be able 
to exist together under any other system. 
On cattle-breeding establishments on the pampas, 
where it is usual to keep a large number of fierce- 
tempered dogs, I have observed these animals a 
great deal, and presume that they are very much 
like feral dogs and wolves in their habits. Their 
quarrels are incessant; but when a fight begins 
the head of the pack as a rule rushes to the 
