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Step 21. Man, who was developed out of the former race by 
the gradual development of the brain and the larynx, 
so that language and mental power were the result. All 
these changes were produced by natural selection, result- 
ing in the survival of the fittest.-’^ 
Such is the creed of the learned professor, and such must 
be, he says, the creed of every man who claims to be 
scientific. ^^We must,^"’ writes the professor, either accus- 
tom ourselves to the idea that all the various species of animals 
and plants, man also included, originated independently of 
each other by the supernatural process of a divine creation — 
or we are compelled to accept the theory of descent in its 
entirety, and trace the human race, equally with the various 
animal and plant species, from an entirely simple primaeval 
parent form. Between these two assumptions there is no 
third course j either a blind belief in creation, or a scientific 
theory of evolution. * 
But to proceed. Let us now inquire into the grounds for 
believing that man has been evolved out of the monera. Here 
is the answer. Because, in all living creatures there is a simi- 
larity of organization, and a graduation which has a general 
relation to the historic succession of life. 
We admit that there are many points in which the structure 
of one set of animals resembles another set in the same sub- 
kingdom. Thus, all the protozoa are built up on the same 
general type; all the coelenterata on another; all the annuloida 
on another ; all the annulosa on another ; and so on, through 
the whole animal kingdom. But while the animals in each sub- 
kingdom are marked by a similarity of structure, those of an- 
other sub-kingdom are marked by differences equally as striking. 
Every student of zoology knows that, while in the sub-kingdom 
annulosa the main masses of the nervous matter lie on the 
ventral side of the body, in the sub-kingdom vertebrata they 
lie on the dorsal side. Other points of structure might be 
noticed equally as marked ; indeed, we may say that each 
sub-kingdom is characterised by a well-defined structure of 
its own. And what is still more remarkable, the blood corpus- 
cles of the different classes of the vertebrata have a character 
of their own, both as regards size and form. In fishes, 
reptiles, and birds, they are oval, while in mammals they are, 
with one exception, round. At the same time, they are 
smaller than those in the three other classes. 
^ The Evolution of Man, vol. ii. p. 36. 
