embryology, a fact which to my mind is a striking proof of the truth of the evolution theory. In embryology the starting-point in the development of the animal is the ovum, which is virtually a living unicellular organism. Although almost microscopic in dimensions, the ovum carries with it the fundamental elements of heredity, and moulds the subsequent nutrition of the embryo to such an extent that the features, and many characteristic traits of the parents, are reproduced in the adult life of the new being. So complete is the parallelism between the progressive changes which take place during fœtal life, and the gradual development of animals into the higher stages of existence, that Haeckel and Von Baer formulated the theory that the development of the individual is a recapitulation of the race to which he belongs. The meaning of this, when applied to man, is that in his embryological stage we have presented to us in the short space of nine months the successive phases of his entire career on the globe since he first emerged from his protozoan swaddling-clothes. Moreover, during adult life he carries with him some traces of his ancestral condition in the form of the vestigial, or so-called rudimentary organs, such as canine teeth, the coccyx, the inter- and supra-condyloid foramina of the humerus, the appendix vermiformis, remnants of certain muscles, etc., which are apparently useless in the human economy; but their homologues in other animals have special functions assigned to them. What pregnant truths are embodied in the following remarks by Professor Huxley:—
"He (the investigator) also discovers rudimentary teeth, which are never used, in the gums of the young calf and in those of the fœtal whale: insects which never bite have rudimental jaws, and others which never fly have rudimental wings: naturally blind creatures have rudimental eyes; and the halt have rudimentary limbs. So, again, no animal or plant puts on its perfect form at once, but all have to start from the same point, however various the course which each has to pursue. Not only men and horses, and cats and dogs, lobsters and beetles, periwinkles and mussels, but even the very sponges and animalcules, commence their existence under forms which are essentially undistinguishable, and this is true of all the infinite variety of plants. Nay, more, all living beings march side by side along the high road of development, and separate the later the more like they are; like people leaving church, who all go down the aisle, but having reached the door, some turn into the parsonage, others go down the village, and others part only in the next parish. A man in his development runs for a little while parallel with, though never passing
