10 BniANA. MAMMALIA. Bimana. 
with grasping hands, and in the majority these are even 
furnished with opposable thumbs ; but these thumbs 
are much shorter than in the human hand, and the 
fingers are far from possessing the same amount of 
independent mobility as those of man. It is to this 
great perfection of his hand, together with the power 
which he possesses of making use of this organ, inde- 
pendently of the position of the other parts of the body, 
in other words, its complete removal from the system 
of locomotive organs, that man is mainly indebted for 
his capability of employing the intellect Avith which it 
is his proud prerogative to be endowed, and for his 
poAver of obtaining a mastery over all the rest of the 
animated creation. We cannot, in fact, imagine any 
modification of the human form Avhich Avould render it 
a more fitting vehicle for the exercise of the mental 
powers possessed by man ; nor can Ave conceive the 
performance of the various actions instigated by those 
powers by the instrumentality of any other knoAvn 
form of organization. Thus, then, from the general 
structure of the AAdiole body, Ave obtain sufficient evi- 
dence of the title possessed by the human species to 
rank as a distinct order in our classification, to stand 
out clearly at the head of the animated Avorld, and not 
merely as the highest member of the group of monkeys. 
The principal phj'sical characters by Avhich man is 
distinguished at the first glance from all the other Mam- 
malia are, therefore, as may be gathered from Avhat Ave 
have already stated, his adaptation to an erect posture; 
the great perfection of his anterior members, and espe- 
cially of his hands; the large size of his brain and skull; 
and the comparative smallness of the facial bones. 
Besides these Ave find other ])hysical peculiarities Avhich 
equally serve to characterize the order Bimana. Each 
jaAV contains teeth of three kinds, namely, four incisors, 
tAvo canines, and ten molars ; and these are of nearly 
equal height, and arranged in a continuous series in 
each JaAV, never exhibiting that diversity of size, or the 
gaps separating the canines from the incisors or molars, 
Avhich occur in all other living mammals. The molars 
have their croAvns uniformly enamelled, more or less 
cubical in form, and furnished Avith obtuse tubercles 
on the upper surface, a conformation indicative of the 
adaptation of the human species to a mixed diet. The 
skin is naked, or but sparingly clothed Avith hairs, ex- 
cept upon the head and some other parts of the body, 
and the nails are all flat and broad. 
It is unnecessary to dwell upon the intellectual supe- 
riority enjoyed by the human race over the lower 
animals, as tliis must be sufficiently manifest to every 
one. The highest intelligence exhibited by an animal 
must be regarded as inferior to that of a child of two or 
three years old; and it is only the astonishment felt at 
witnessing the effects of education upon some of the 
most highly-endoAved creatures, that often leads the 
superficial observer to attribute to them a higher degree 
of reasoning power than they really possess. It is, also, 
in the mind of man alone that has been implanted that 
belief in the existence of a Deity and in the immortality 
of his OAvn soul, Avhich is the foundation of all religious 
sentiment — a sentiment Avhich, although often debased 
by the most degrading superstitions, seems to be inher- 
ent in the human race. 
There is one other manifestation of the intellectual 
poAvers of man that must not be altogether passed over 
in silence, namely, the faculty of speech, or of producing 
and understanding articulate sounds. This appears to 
be peculiar to the human species; for, although there can 
be no doubt that in many animals there is some poAver 
of communicating intelligence from one individual to 
another, none of them possess a language. It is by 
means of this peculiar faculty that the progress of man- 
kind is insured. It is by this that the knoAvledge 
acquired and the discoveries made in one age, or in 
one locality, are transmitted to later times or to distant 
countries; AA'hilst by the reduction of language to Avritten 
characters, the insecurity of oral tradition is got rid of, 
and the influence of every discovery is extended and 
made more permanent. 
We come noAv to one of the most difficult subjects 
connected Avith the physical history of man — the ques- 
tion of the primitive unity or diversity of the human 
species ; in other Avords, Avhether the original proge- 
nitors of the entire human population of the globe 
Avere perfectly identical in their essential characters, or 
Avhether tire diversity which Ave noAV observe in different 
races be the result of a primary specific difference. 
There is no doubt that Avhen we compare together the 
extreme varieties of humanity, as, for instance, Euro- 
peans, Negroes, American Indians, Chinese, and Aus- 
tralian savages, Ave may easily find in the form of the 
head and face, the colour of the skin, the nature of the 
hair and the general structure of the body, distinctive 
characters, such as in most cases of zoological investi- 
gation Avould lead us to regard these different forms as 
belonging to so many species. But this question, unfor- 
tunately, cannot be so easily settled ; because, betAveen 
these extremes of diversity we find so many inter- 
mediate steps, so many points Avhere the physical 
characters of different marked varieties seem to be 
intimately blended, that it is often impossible to say to 
Avhich of tAvo supposed species a given tribe of men is 
to be referred. 
If we take the opposite supposition, namely, that all 
the varieties of man have been produced by the modifi- 
cation of a single species, or to put the matter more 
clearly, the progeny of a single pair, it is difficult to 
concede that mere climatal influences and differences 
in the mode of life could have produced such immense 
changes, not only in the colour, but also in the confor- 
mation of different tribes. One of the strongest physical 
arguments adduced in favour of the unity of the human 
species consists in the continued fertility of mixed 
races, even Avhere the grounds for the establishment of 
distinct species are apparently the strongest — as, for 
instance, in the progeny of Europeans and Negroes. 
But this argument is fallacious, as, although the majority 
of animal hybrids may be sterile, there are undoubtedly 
cases in Avhich this rule is departed from ; indeed, it is 
not improbable that some of our most valuable domestic 
animals are hybrids. The test of colour, Avhich is 
often relied upon as an indication of variation distinctly 
referable to a recognizable cause, namely, the influence 
of a greater or less degree of heat, does not always 
apply; for although Ave may state as a general rule, that 
the inhabitants of hot plains are darker than those of 
