REVIEWS. 
239 
ment of the zygomatic (cheek) bones and of the masseter muscles. The 
temporal fossae are deep ; the jaws massive ; the eyes deeply set, and 
approaching one another very closely ; the iris is dark-coloured, and the 
glance piercing and savage. The shafts of the hones, especially of the 
anterior extremities, are long; so much so, that in France and England 
a special form of glove is manufactured for the American market, having the 
fingers exceptionally elongated. The cavities of these bones are small ; the 
nails soon assume a lengthened and pointed shape. The pelvis of the woman 
approaches that of the man in form. We have softened down some of the 
harsher features in this description.” 
The next link in the author’s chain of reasoning, whereby he would prove 
the unity of the human species, is the production of hybrids and mongrels. 
The former, as is doubtless well known to all our readers, are the results 
of an intercrossing of two individuals of two different species : the mule, for 
example, being the hybrid of the horse and ass ; whilst, on the other hand, 
mongrels are derived from individuals of different races or varieties, of which 
numerous instances present themselves in our races of domesticated animals. 
With reference to these phenomena, the evidence adduced by the author 
serves to show that the production of mongrels is always easy, however 
greatly the races may differ from one another. It takes place daily between 
individuals left entirely to themselves, and man has often more difficulty in 
preventing than in promoting the intercourse. Neither does it interfere with 
the fertility of the offspring, which is equal to, if not greater than that mani- 
fested in the union of individuals of the same race. 
Hybridism, or the intercrossing of species, is in the immense majority 
of cases impossible, even where the two species brought into relation with 
one another present the most striking affinities. “ It is extremely rare amongst 
free, or wild individuals, and in captive or domesticated species it is brought 
about only with the aid of manoeuvres, which often fail to produce a result. 
Under its influence, even in the most favourable cases, fertility (almost 
with one exception only) becomes irregular, and is sometimes diminished 
to an enormous extent.” 
Much space is devoted by the author to the consideration of these phe- 
nomena, and he seems almost to have exhausted the subject, for his evidence 
is drawn from every conceivable source. His dissertation upon the past and 
future operations of man, and the influence which lie exercises in the formation 
of hybrids and mongrels, is deeply interesting, and well deserves a passing 
notice. He asks whether it will ever be possible to produce fertile hybrids, 
and his reply is, “probably not but “ the power of man is very great, and 
less than all others are we disposed to assign to it limits based upon our 
present knowledge. This power has already been strikingly exhibited in the 
order of facts to which w r e have referred. There is not known a single case of 
hybridism between wild species,” (i.e., spontaneous crossing of species in the 
wild state,) “ but man has obtained fertile unions, not only between species 
that have submitted for centuries to his domination, but between those 
which it is difficult to tame, between the tiger and lion. He has done even 
more, when, after innumerable fruitless attempts, he has at length created 
series of hybrids.” 
In concluding his remarks on hybrids and mongrels, the author says that 
if w r e ascend in imagination to the origin of mongrel races, we find them 
