PHYSICAL CONDITIONS AT BEGINNING OF LIFE 583 



phyte to a giant redwood, is immeasurably, almost infinitely 

 greater than the step from a layer of colloidal polyfetides, in 

 a salt solution, to the mucilaginous smear which we call 

 Myxomycetes. There is infinitely greater mystery in the evolu- 

 tion of a sentient being, a Newton, a Wagner, from an amoeba 

 or its prototype, than in the process by which the phosphorised 

 protein or granular substance of the cell-nucleus becomes 

 capable of auto-synthesis — that is to say, in the only decisive 

 sense of the word, alive. It is infinitely more of a wonder 

 how an almost formless microscopic germ-cell becomes a 

 thinking mechanism, which may weigh the sun or hear in its 

 brain the unwritten, unsounded strains of the Symphonie 

 Pathetique. This marvellous unfolding we may trace, literally, 

 step by step from the first undifferentiated layers of the 

 embryo to the being quivering with a myriad impressions 

 and influences, of which the music is the unconscious echo. 



We have a fairly definite measure of these biological ' 

 " distances," in the simple question of size. An adult man is 

 on the average at least twenty million times in weight the 

 microscopic germ from which he springs. 1 The giant fin-back 

 whale is hundreds of millions of millions of times the size of 

 the smallest bacterium known. On the other hand, it is now 

 known that there are living beings containing at most not 

 more than a few hundred colloid particles, 2 and it seems 

 extremely doubtful if these individual particles are alive (i.e. 

 self-reproducing). 



To say, therefore, that there is more mystery in a bacterium 

 or a germ-cell than in the individual development of a human 

 being or in the historical evolution of life on earth, is utterly 

 to misrepresent the present state of our knowledge. We can 

 describe the successive stages by which the germ becomes a 

 man; we can imaginatively reconstruct the process by which a 

 bacterium or some other unicellular form became in the course 

 of a hundred million years a hundred-ton whale. But we 

 have no clear idea as to the causes of differentiation nor the 

 factors of evolution. 



It is equally true that we have as yet no clear idea as to 

 how in nature a simple amino acid becomes a complex phos- 



1 Cf. Muhlmann, Ursache des Alters, 1908, for lit. 



2 L. Errara, Rec. de PInst. Bot. Brux. 6, 73, 1903 ; MacKendrick, Rep. Brit. 

 Asso. 1901, p. 808. 



