life: its nature, origin, and maintenance SCHAFER. 505 



was originally evolved from it may, as Macallum has suggested, 

 have taken the form of diffused ultra-microscopic particles of living 

 substances;^ and even if they were not dilTused but aggregated into 

 masses, these masses could have been physically nothing more than 

 colloidal watery slime which would leave no impress upon any geo- 

 logical formation. Mja-iads of years may have elapsed before some 

 sort of skeleton in the shape of calcareous or siliceous spicules began 

 to evolve itself, and thus enabled ''life" which must already have 

 possessed a prolonged existence, to make any sort of geological record. 

 It follows that in attempting to pursue the evolution of livhig matter 

 to its begmning in terrestrial history we can only expect to be con- 

 fronted with a blank wall of nescience. 



The problem would appear to be hopeless of ultimate solution, 

 if we are rigidly confined to the supposition that the evolution of life 

 has only occurred once in the past history of the globe. But are we 

 justified in assuming that at one period only, and as it were by a 

 fortunate and fortuitous concomitation of substance and circum- 

 stance, livmg matter became evolved out of nonliving matter — life 

 became established? Is there any valid reason to conclude that at 

 some previous period of its history our earth was more favorably 

 circumstanced for the production of life than it is now ? ^ I have 

 vauily sought for such reason, and if none be forthcommg the con- 

 clusion forces itself upon us that tlie evolution of nonliving into 

 living substance has happened more than once — -and we can be by 

 no means sure that it may not be happening still. 



It is true that up to the present there is no evidence of such hap- 

 pening; no process of transition has hitherto been observed. But 

 on the other hand, is it not equally true that the kind of evidence 

 wliich would be of any real value in determining this question has 

 not hitherto been looked for? We may be certain that if life is being 

 produced from nonliving substance it will be life of a far simpler 

 character than any that has yet been observed — in material which 

 we shall be uncertain whether to call animate or inanimate, even if 

 we are able to detect it at all, and which we may not be able to 

 visualize physically even after we have become convinced of its 

 existence.^ But we can look with the mind's eye and follow in 

 imagination the transformation which nonliving matter may have 



1 There still exist in fact forms of life which the microscope can not show us (E. A. Minchin, presidential 

 address to Quekett Club, 1911), and germs which are capable of passing through the pores of a Chamberland 

 filter. 



2 Chalmers Mitchell (Art. "Life," Encycl. Brit., eleventh edition) writes as follows: "It has been sug- 

 gested from time to time that conditions very unlilce those now existhig were necessary for the first appear- 

 ance of life, and must be repeated if living matter is to bo reconstituted artificially. No support for such a 

 view can be derived from observations of the existing conditions of life."— Cf. also .T. Hall-Kdwards, op. cit. 



2 "Spontaneous generation of life could only bo perceptimlly demonstrated by filling in the long terms 

 of a series between the complex forms of inorganic and the simplest forms of organic substance. Were this 

 done, it is quite possible that wo should be unable to say (especially considering the vagueness of our defi- 

 nitions of life) where life Ijogan or ended."— K. Pearson, Grammar of Science, second edition, 1900, p. 350. 



