28 EVOLUTION AND MAN S PLACE IN NATURE 



this hypothesis ; and it is more natural to one study 

 ing life-history as seen in the vegetable world, than it 

 is to one devoted to animal biology. While, how 

 ever, Nageli favours a mechanico-physiological doc 

 trine of descent/ he admits that among known livino- 



o o 



beings there are none which could have arisen by 

 abiogenesis, for the lowest plants have a cell-mem 

 brane, and the mon-era 1 cannot live independently, i.e. 

 without the production from decomposition of other 

 organisms. 2 Professor Huxley puts the conclusion 

 strongly : The fact is that at the present moment 

 there is not a shadow of trustworthy direct evidence 

 that abiogenesis does take place, or has taken place 

 within the historic period during which existence of 

 life on the globe is recorded. 3 There is unbroken 

 scientific testimony for the conclusion, that life comes 

 only from life. In all its known forms, life is a 

 manifestation of descent. Above the material basis 

 of things, there appears a new start, presenting con 

 ditions of progress otherwise impossible. We do not 

 find any explanation of life by reference to a certain 

 disposition of material molecules. Nor are we helped 

 by finding that protoplasm, the physical basis of 

 life, contains the four elements, carbon, hydrogen, 

 oxygen and nitrogen in very complex union, even 

 though gravitation and moisture and heat are 

 supplied as attendant conditions. If it is certain 

 that we can have no knowledge of the nature of either 

 matter or spirit, and that the notion of necessity is 

 something illegitimately thrust into the perfectly 



1 The simplest of all organisms. 



2 Mechanisch-Physiologische Theorie der Abstammungslehre. 

 Biology, Encyd. Brit. 9th ed. 



