Chap. VII. 
THE EACES OF MAN. 
227 
take the description of a group of highly varying 
organisms, has encountered cases (I speak after ex- 
perience) precisely like that of man ; and if of a cautious 
disposition, he will end by uniting all the forms which 
graduate into each other as a single species ; for he will 
say to himself that he has no right to give names to 
objects which he cannot define. Cases of this kind occur 
in the Order which includes man, namely in certain 
genera of monkeys ; whilst in other genera, as in Cerco- 
pithecus, most of the species can be determined with 
certainty. In the American genus Cebus, the various 
forms are ranked by some naturalists as species, by 
others as mere geographical races. Now if numerous 
specimens of Cebus were collected from all parts of 
South America, and those forms which at present ap- 
pear to be specifically distinct, were found to graduate 
into each other by close steps, they would be ranked by 
most naturalists as mere varieties or races ; and thus the 
greater number of naturalists have acted with respect 
to the races of man. Nevertheless it must be confessed 
that there are forms, at least in the vegetable king- 
dom , 18 which we cannot avoid naming as species, but 
which are connected together, independently of inter- 
crossing, by numberless gradations. 
Some naturalists have lately employed the term 
u sub-species ” to designate forms which possess many of 
the characteristics of true species, but which hardly de- 
serve so high a rank. Now if we reflect on the weighty 
arguments, above given, for raising the races of man to 
the dignity of species, and the insuperable difficulties 
on the other side in defining them, the term “ sub- 
18 Prof. Nageli lias carefully described several striking cases in bis 
- c Botaniscbe Mittheilungen,’ B. ii. 1866, s. 294-369. Prof. Asa Gray 
has made analogous remarks on some intermediate forms in the Com- 
positse of N. America. 
Q 2 
