698 APPENDIX D. 



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 com- 

 menced, were the superior organisms from which these lowest or- 

 ganisms 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 pene- 

 trate deep enough to see that a tenable hypothesis respecting the 

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

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



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

 lieve. Granting that the formation of organic matter, and the evo- 

 lution of life in its lowest forms, may go on under existing cos- 

 mical conditions ; 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 tempera- 

 ture at which the higher organic compounds are unstable ; 1 con- 

 ceive that the moulding of such organic matter into the simplest 

 types, must have commenced with portions of protoplasm more 

 minute, more indefinite, and more inconstant in their characters, 

 than the lowest Rhizopods less distinguishable from a mere frag- 

 ment of albumen than even the Protogenes of Professor Haeckel. 

 The evolution of specific shapes must, like all other organic evolu- 

 tion, have resulted from the actions and reactions between such in- 

 cipient types and their environments, and the continued survival 

 of those which happened to have specialities best fitted to the 

 specialities of their environments. To reach by this process the 

 comparatively well-specialized 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 al- 

 most 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 



