The figure annexed represents the skull of a man belonging to the stone age, found in Denmark; to this skull, which is known by the name of the Borreby skull, we shall have to allude again in the course of the present work; fig. 3 represents the skull of a gorilla; fig. 4 that of an orang-outang; fig. 5 that of the _Cynocephalus_ ape; fig. 6 that of the _Macacus_. Place the representation of the skull found in Denmark in juxtaposition with these ill-favoured animal masks, and then let the reader draw his own inference, without pre-occupying his mind with the allegations of certain anatomists imbued with contrary ideas. [Illustration: Fig. 2.--Skull of a Man belonging to the Stone Age (the _Borreby Skull_).] [Illustration: Fig. 3.--Skull of the Gorilla.] [Illustration: Fig. 4.--Skull of the Orang-Outang.] [Illustration: Fig. 5.--Skull of the Cynocephalus Ape.] [Illustration: Fig. 6.--Skull of the _Macacus_ Baboon.] Finding themselves beaten as regards the skulls, the advocates of transmutation next appeal to the bones. With this aim, they exhibit to us certain similarities of arrangement existing between the skeleton of the ape and that of primitive man. Such, for instance, is the longitudinal ridge which exists on the thigh-bone, which is as prominent in primitive man as in the ape. Such, also, is the fibula, which is very stout in primitive man, just as in the ape, but is rather slender in the man of the present period. When we are fully aware how the form of the skeleton is modified by the kind of life which is led, in men just as in animals, we cannot be astonished at finding that certain organs assume a much higher development in those individuals who put them to frequent and violent use, than in others who leave these same organs in a state of comparative repose. If it be a fact that the man of the epoch of the great bear and the mammoth had a more robust leg, and a more largely developed thigh-bone than most of the races of existing man, the reason simply is, that his savage life, which was spent in the midst of the wild beasts of the forest, compelled him to make violent exertions, which increased the size of these portions of his body. Thus it is found that great walkers have a bulky calf, and persons leading a sedentary life have slender legs. These variations in the structure of the skeleton are owing, therefore, to nothing but a difference in the mode of life.