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organisms. By what kind of logic, then, is it inferrible that 

 organic life was initiated after a manner like that in which Infusoria 

 are said to be now spontaneously generated? Where, before life 

 commenced, were the superior organisms from which these lowest 

 organisms obtained their organic matter ? Without doubting that 

 there are those who, as the reviewer says, " can penetrate deeper 

 than Mr. Spencer has done into the idea of universal evolution," 

 and who, as he contends, prove this by accepting the doctrine of 

 " spontaneous generation " ; I nevertheless think that I can penetrate 

 deep enough to see that a tenable hypothesis respecting the origin 

 of organic life must be reached by some other clue than that fur- 

 nished by experiments on decoction of hay and extract of beef. 



From what I do not believe, let me now pass to what I do believe. 

 Granting that the formation of organic matter, and the evolution of 

 life in its lowest forms, may go on under existing cosmical condi- 

 tions ; but believing it more likely that the formation of such matter 

 and such forms, took place at a time when the heat of the Earth's 

 surface was falling through those ranges of temperature at which 

 the higher organic compounds are unstable; I conceive that the 

 moulding of such organic matter into the simplest types, must have 

 commenced with portions of protoplasm more minute, more in- 

 definite, and more inconstant in their characters, than the lowest 

 Rhizopods— less distinguishable from a mere fragment of albumen 

 than even the Protogenes of Professor Haeckel. The evolution of 

 specific shapes must, like all other organic evolution, have resulted 

 from the actions and reactions between such incipient types and 

 their environments, and the continued survival of those which hap- 

 pened to have specialities best fitted to the specialities of their en- 

 vironments. To reach by this process the comparatively well-spe- 

 cialized forms of ordinary Infusoria, must, I conceive, have taken an 

 enormous period of time. 



To prevent, as far as may be, future misapprehension, let me 

 elaborate this conception so as to meet the particular objections 

 raised. The reviewer takes for granted that a " first organism " 

 must be assumed by me, as it is by himself. But the conception of 

 a " first organism," in anything like the current sense of the words, 

 is wholly at variance with conception of evolution ; and scarcely 

 less at variance with the facts revealed by the microscope. The 

 lowest living things are not properly speaking organisms at all ; for 

 they have no distinctions of parts — no traces of organization. It is 

 almost a misuse of language to call them " forms " of life : not only 

 are their outlines, when distinguishable, too unspecific for description, 

 but they change from moment to moment and are never twice alike, 

 either in two individuals or in the same individual. Even the word 

 " type " is applicable in but a loose way ; for there is little constancy 

 in their generic characters : according as the surrounding conditions 

 determine, they undergo transformations now of one kind and now of 



