306 THE HISTORY OF CREATION. 
brain of the bird (/) is scarcely distinguishable from that of 
the tortoise (#), and in like manner the brain of the dog (@) 
is as yet almost the same as that of man (H). If, on the 
other hand, we compare the brains of these four vertebrate 
animals in a fully developed condition, we find them so 
very different in all anatomical particulars, that we cannot 
doubt for a moment as to which animal each brain belongs. 
I have here explained the original equality, the gradual 
commencement, and the ever increasing separation or 
differentiation of the embryos in the different vertebrate 
animals, taking the brain as a special example, just because 
this organ of the soul’s activity is of special interest. But I 
might as well have discussed in its stead the heart, or the 
liver, or the limbs, in short, any other part of the body, since 
the same wonder of creation is here ever repeated, namely, 
this, that all parts are originally the same in the different 
vertebrate animals, and that the variations by which the 
different classes, orders, families, genera, etc., differ and 
deviate from one another, are only gradually developed. 
There are certainly few parts of the body which are so 
differently constructed as the limbs or extremities of the 
vertebrate animals. Now, I wish the reader to compare in 
Fig. A—H on Plates II. and III, the four extremities (bv) of 
the embryos with one another, and he will scarcely be able 
to perceive any important differences between the human 
arm (H bv), the wing of a bird (F bv), the slim foreleg of a 
dog (G@ bv), and the plump foreleg of the tortoise (Z bv). In 
comparing the hinder extremities (bh) in these figures he 
will find it equally difficult to distinguish the leg of a man 
(H bh), of a bird (F bh), the hind-leg of a dog (G 6h), and 
that of a tortoise (bh). The fore as well as the hinder 
