8G6 Professor Huxley [April 9, 



investigation since 1859 has been in the direction of removing the 

 difficulties which the apparent breaks in the series created at that 

 time ; and the recognition of gradation is the first step towards the 

 acceptance of evolution. 



As another great factor in bringing about the change of opinion 

 which has taken place among naturalists, I count the astonishing 

 progress which has been made in the study of embryology. Twenty 

 years ago, not only were we devoid of any accurate knowledge of the 

 mode of development of many groups of animals and plants, but the 

 methods of investigation were rude and imperfect. At the present 

 time there is no important group of organic beings the development 

 of which has not been carefully studied, and the modern methods of 

 hardening and section-making enable the embryologist to determine 

 the nature of the process in each case with a degree of minuteness 

 and accuracy which is truly astonishing to those whose memories 

 carry them back to the beginnings of modern histology. And the 

 results of these embryological investigations are in complete harmony 

 with the requirements of the doctrine of evolution. The first begin- 

 nings of all the higher forms of animal life are similar, and however 

 diverse their adult conditions, they start from a common foundation. 

 Moreover, the process of development of the animal or the plant from 

 its primary egg or germ is a true process of evolution — a progress 

 from almost formless to more or less highly organized matter, in 

 virtue of the properties inherent in that matter. 



To those who are familiar with the process of development, all a 

 priori objections to the doctrine of biological evolution appear childish. 

 Any one who has watched the gradual formation of a complicated 

 animal from the protoplasmic mass which constitutes the essential 

 element of a frog's or a hen's egg has had under his eyes sufficient 

 evidence that a similar evolution of the whole animal world from the 

 like foundation is, at any rate, possible. 



Yet another product of investigation has largely contributed to 

 the removal of the objections to the doctrine of evolution current in 

 1859. It is the proof affi)rded by successive discoveries that Mr. 

 Darwin did not over-estimate the imperfection of the geological 

 record. No more striking illustration of this is needed than a 

 comparison of our knowledge of the mammalian fauna of the Tertiary 

 epoch in 1859 with its present condition. M. Gaudry's researches 

 on the fossils of Pikermi were published in 1868, those of Messrs. 

 Leidy, Marsh, and Cope on the fossils of the Western Territories of 

 America have appeared almost wholly since 1870, those of M. Filhol 

 on the phosphorites of Quercy in 1878. The general eficct of these 

 investigations has been to introduce to us a multitude of extinct 

 animals, the existence of which was previously hardly suspected ; just 

 as if zoologists were to become acquainted with a country, hitherto 

 unknown, as rich in novel forms of life as Brazil or South Africa 

 once were to Europeans. Indeed the fossil fauna of the Western 

 Territories of America bids fair to exceed in interest and importance 



