Page:Popular Science Monthly Volume 12.djvu/193

Rh condemned as morally reprehensible and theologically dangerous. In this, the authority of Cuvier in regard to evolution acted as the authority of Newton had done in regard to the undulatory theory of light.

In like manner the views of Oken met with resistance, especially his deduction that the highest animals are the result of development, not of creation. Man, he significantly says, has been developed, not created. He conceived all Nature to be in a process of evolution. His demonstration, that the bones of the skull are only vertebral modifications, however, reconciled many persons to a more favorable opinion of his hypothesis of development.

Geoffroy St.-Hilaire (1828) did not doubt that animals now living are descended by an unbroken succession from extinct ones, by transformation from form to form; that different species are degenerations of the same type, being due to the influence of the environment (monde ambiant). He thus became the opponent of Cuvier, and did very much to break down the influence of that zoölogist. In these variations he considered that the organism is passive, differing in this from Lamarck, who thought it active. His views of the influence of the environment were very precise: thus he thought that birds arose from reptiles, through the diminution of carbonic acid and increase of oxygen in the air, at the time of the formation of coal; the activity of the animal circulation becoming greater, and the reptile scales being transformed into the feathers of the bird. As is now known, this was substantially a correct interpretation.

Though the principles of the doctrine of evolution were thus thoroughly understood, the control of heredity, the influence of environment, the modeling by adaptation, public attention failed to be drawn to it until 1844, when there was published in England an anonymous book under the title of the "Vestiges of the Natural History of Creation." In this the author set forth Lamarck's views, and the work, being clearly and attractively composed, passed through a great many editions. Very fortunately, it may be said, it accepted some unsubstantiated facts and contained some physical mistakes. These tempted many skillful and bitter criticisms of hostile theologians. The reviews and journals were filled with their attacks and answers to them. Thus, happily, the whole subject was brought into such prominence that it could be withdrawn into obscurity no more.

In the discussions of this book the author made use of a most important anatomical discovery, that even in the case of the highest species, man himself, the embryo does not simply grow or increase in size, but passes in succession through a series of forms, which, examined from epoch to epoch, are totally dissimilar. It had been the vulgar opinion that after the first moment of conception all the parts of the animal that is to be are present, and that they simply grow. The human embryo, according to this, reaches birth very much in the