THE UNITY OF NATURE. 275 



Our modern biogeny gives a purely physiological 

 explanation of the facts of embryology, in assigning 

 the functions of heredity and adaptation as their 

 causes. The great biogenetic law, which Baer failed 

 to appreciate, reveals the intimate causal connection 

 between the ontogenesis of the individual and the 

 phylogenesis of its ancestors ; the former seems to be 

 a recapitulation of the latter. Nowhere, however, in 

 the evolution of animals and plants do we find any 

 trace of design, but merely the inevitable outcome of 

 the struggle for existence, the blind controller, instead 

 of the provident God, that effects the changes of 

 organic forms by a mutual action of the laws of 

 heredity and adaptation. And there is no more trace 

 of " design " in the embryology of the individual 

 plant, animal, or man. This ontogeny is but a brief 

 epitome of phytogeny, an abbreviated and condensed 

 recapitulation of it, determined by the physiological 

 laws of heredity. 



Baer ended the preface to his classical Evolution of 

 Animals (1828) with these words : " The palm will be 

 awarded to the fortunate scientist who succeeds in 

 reducing the constructive forces of the animal body to 

 the general forces or life-processes of the entire world. 

 The tree has not yet been planted which is to make 

 his cradle." The great embryologist erred once more. 

 That very year, 1828, witnessed the arrival of Charles 

 Darwin at Cambridge University (for the purpose of 

 studying theology!) — the "fortunate scientist" who 

 richly earned the palm thirty years afterwards by his 

 theory of selection. 



In the philosophy of history — that is, in the general 

 reflections which historians make on the destinies 

 of nations and the complicated course of political 



