THE CAREER OF HERBERT SPENCER ii 



But this fundamental criticism aside, Spencer's handling of biolog- 

 ical problems is nothing short of masterful. In his chapters on 

 growth, development, function, adaptation, generation ("genesis"), 

 heredity, variation, etc., although not a specialist in any branch of 

 biology, he marshals an immense body of facts in support of funda- 

 mental principles, many of which had never before been discovered. 

 In dealing with heredity he postulates the existence of " physiological 

 units," later changed to " constitutional units." The " Principles of 

 Biology " was published in 1864, and therefore Spencer could have 

 known nothing of Darwin's " pangenesis," treated in his " Variations 

 of Animals and Plants under Domestication," which appeared in 1868. 

 But Spencer's " physiological units," as he points out,^° are not at all 

 the same as Darwin's " gemmules." They are still less similar to 

 Weismann's " biophores."^^ They are nothing but " compound mole- 

 cules (as much above those of albumen in complexity as those of albu- 

 men are above the simplest compounds," and are for the same organ- 

 ism " substantially of one kind." Why he did not admit that they are 

 merely forms of protoplasm we do not know, but certain it is that 

 biologists are now coming to believe that no hereditary units in the 

 sense of independent bodies exist, and that all the phenomena of 

 heredity, obscure and recondite as they are, can be as easily conceived 

 to result from the action of protoplasm in various ways not yet fully 

 understood, as from any imaginary bearers of hereditary " Anlagen."^^ 



It is in Part III. on the " Evolution of Life " that the philosopher 

 comes forth in his full power. After disposing of the special creation 

 hypothesis, he attacks the cosmic principles underlying the organic 

 world. Many of those enumerated in " First Principles " are shown 

 to be in full force on the biotic plane. The process from homogeneity 

 to heterogeneity finds its clearest exemplifications here, and the two 

 great principles of differentiation and integration are formulated and 

 illustrated with wonderful force. "We can not here even enumerate all 

 the biological principles set forth in this work, but the application of 

 the principle of equilibration to the organic world can not be passed 

 over in silence. The Lamarckian principle of increase by use and 

 atrophy from disuse, called somewhere by Spencer "use-inheritance," 

 and early recognized by him as "the inheritance of functionally- 

 acquired modifications," now becomes, in the new terminology of 

 biology, " direct equilibration," while natural selection, which Spencer, 

 along with many others mentioned by Darwin in the later editions of 

 the " Origin of Species," had foreshadowed before that work appeared, 



" " Life and Letters," Vol. I., p. 199. 

 "/btd., Vol. IL, p. 52. 



"^ Cf. Minot, " The Problem of Age, Growth, and Death," New York, 1908, 

 pp. 233 ff. 



