86 THE TOWER MENAGERIE, 
tail of a domestic dog, the tip of that very variable organ 
is also constantly white; so that we are still driven to 
recur to the tail alone for the only uniform physical 
characteristics that have been pointed out to distinguish 
an animal, which every one recognises at first sight, and 
which indeed it is impossible to mistake. 
But it is to the moral and intellectual faculties of the 
Dog that we must look for those remarkable peculiarities 
which distinguish him in so eminent a degree not only 
from his immediate neighbours, but also from every 
other quadruped. Unfortunately we have not the means 
of comparing him in a pure state of nature with the 
other animals of his tribe; for although it has been 
repeatedly attempted to determine his primitive stock, 
there can be no doubt that upon this point we are stil! 
as much as ever in the dark. There exist, however, in 
various parts of the world, considerable numbers of 
Dogs, the descendants unquestionably of races formerly 
domesticated, which, to all appearance, differ but little 
in their habits and manners from the Wolf and the 
Jackal, to one or other of which they frequently ap- 
proach in form, and from each of which it has been 
confidently asserted that the domestic species was prima- 
rily derived. But the doubts to which this striking 
similarity might otherwise give rise are instantly re- 
moved by the readiness with which these wild Dogs 
submit to the control of man, and become familiarized 
with that state of servitude to which nature appears to 
have destined them from the first. Other animals may 
indeed be tamed; they may become playful, familiar, 
and even affectionate; but none of them have hitherto 
been taught, even by long-continued training, to exhibit 
