36 THE FOUNDATIONS OF ZOOLOGY 



to show that, in this case, as in others, the responsibility rests 

 with the reader and not with the author; but, however this may 

 be, the opinion that his utterances are inconsistent is real and 

 therefore a proper subject for examination. Huxley's frame of 

 mind in 1854 is embodied in the essay *'On the Educational Value 

 of the Natural History Sciences " (HI. ii.), from which I copy the 

 following passage (p. 43): — 



"What is the cause of this wonderful difference between the 

 dead particles and the living particles of matter appearing in other 

 respects identical? — that difference to which we give the name of 

 life ? I, for one, cannot tell you. It may be that by and by 

 philosophers will discover some higher laws of which the facts of 

 life are particular cases, — very possibly they will find out some 

 bond between physico-chemical phenomena on the one hand and 

 vital phenomena on the other. At present, however, we assuredly 

 know of none ; and I think we shall exercise a wise humility in 

 confessing that for us, at least, . . . this spontaneity of action . . . 

 which constitutes so vast and plain a distinction between living 

 bodies and those which do not live is an ultimate fact : indicating, 

 as such, the existence of a broad line of demarcation between the 

 subject-matter of biological and that of all other sciences." 



Between 1854 and the publication of the essay "On the Physical 

 Basis of Life" in 1868, natural science advanced with strides which 

 have no parallel, and the " Origin of Species " brought about a 

 revolution in our conceptions of the history of living nature. It 

 is not surprising that Huxley's point of view undergoes significant 

 change, and that a new aspect of nature now excites his interest 

 and absorbs his attention. The estabhshment of the doctrine of 

 the continuity of life on a firm basis, and the acceptance of the 

 generalization that all living things are related by birth, had given 

 new meaning to the familiar truth that they are all fundamentally 

 identical in structure; and the essay of 1868 deals with this aspect 

 of living organisms. The essay is regarded by many readers — 

 both those who look upon it with horror and those who make it 

 the basis of a biological creed — as contradictory to the essay of 

 1854; but I, for one, am unable to find in it any basis for this 

 opinion. Its motive — the truth that "protoplasm is the basis of 

 life"; that "it is the clay of the potter, which, bake it and paint 



