i88i.] 
Analyses of Books. 
749 
The researches of modern zoo-geographers supply no evidence 
of a number of independent centres of origin of animal forms. 
The facts speak in favour of successive waves of species spread- 
ing out from the northern hemisphere, and distributing themselves 
over the rest of the world according as channels of communica- 
tion were closed or opened. If this section of the work has been 
recently revised by the author the circumstance is profoundly to 
be regretted. The author, criticising Agassiz, says : — “ Agassiz 
includes New Guinea in the Australian kingdom. He thus 
destroys the homogeneity of the mammalogical fauna.” This is 
a strange assertion if we consider that a species of that charac- 
teristically Australian genus Echidna has recently been discovered 
in New Guinea. 
A prominent feature of the work is the position taken by the 
author on hybridism. Modern research tends to show that hy- 
brids frequently originate in a state of Nature, and that they are 
not necessarily devoid of the power of reproduction. The hybrids 
produced between the domestic cattle and the American bison, 
which belong not merely to different species, but to different 
genera, are a remarkable case in point. It seems to us that the 
author assumes that two species in one genus must be as remote 
from each other morphologically and physiologically as two spe- 
cies in some other genus. Deny this totally unproven proposi- 
tion, and the negative instance of the mule — -upon which so much 
weight is laid by the naturalists of the old school — loses all its 
general value, 
We find, on p. 143, an attempt to justify, or at least to palliate, 
the conduct of Cuvier as regards the discovery of fossil human 
remains in the year 1823. Says our author “ The reproach is 
unjust. Cuvier had too often seen pretended fossil men change 
either into mastodons or salamanders not to be on his guard.” 
Caution in forming judgment on a novel or possibly unique fact 
is doubtless highly commendable ; but when that caution takes 
the form of refusal or neglect to give the disputed specimens a 
full and fair examination, it deserves, and generally obtains, a 
much harsher name. 
Having disposed to his own satisfaction, and doubtless to that 
of official scientists in France, of these accessory questions, M. 
de Quatrefages proceeds to his main subject — the Unity of the 
Human Race. It may perhaps be maintained that the work 
would have had a higher permanent value had it opened with the 
Fifth Book. He shows in succession the possibility of man, 
even in a savage state, gradually overspreading the whole earth 
and becoming gradually acclimatised. He then treats of primi- 
tive man, of the formation of human races under the influence 
of the conditions of existence and of heredity, the origin of 
mixed races and the effects of crossing. He describes the fossil 
races, such as those of Canstadt, Cromagnon, and Furfooz. He 
next turns to the physical characters of mankind, anatomical, 
