106 THE THEORY OF EVOLUTION 



vital activity as a chemico-physical process even of 

 the most complicated kind, or of regarding the organism 

 as merely a machine composed of material parts held 

 together by material forces. 1 



It is important to note also the ' phenomenon ' that 

 all attempts have entirely failed to render spontaneous 

 generation more comprehensible by means of the 

 natural forces known to us, even with the aid of quite 

 ' peculiar ' conditions. Lord Kelvin speaks of physical 

 ' hocus-pocus/ Helmholz and Arrhenius seize upon 

 the boldest hypotheses in order to avoid ' spontaneous 

 generation/ Reinke and E. v. Hartmann find that 

 precisely these ' attempts ' show the inconceivability 

 of it. 0. Hertwig confesses that, ' owing to the present 

 position of natural science, the investigator has cer- 

 tainly no better prospect of results in obtaining living 

 from non-living material than Wagner, in Goethe's 

 " Faust," of brewing a " homunculus " out of a retort/ 

 This firm conviction is therefore certainly based upon 

 the totality of the natural phenomena. 



Nor do we avoid the c miracle ' (and certainly this 

 time a true one) by accepting ' spontaneous generation/ 

 Every living organism shows to-day the persistent 

 striving to combat, by constant contrivance (Mauserung), 

 the ageing and hardening tendency of its material basis, 2 

 by fresh formation of highly complex and unstable 



1 Allgemeine Biologie, p. 159. ' Therefore [by reason of the " essential " 

 differences between mechanical action and vital activity], it is an entirely 

 vain endeavour to imagine that an organism can be understood on the 

 principles of mechanics.' Hertwig. 



2 E. v. Hartmann : Das Problem des Lebens, p. 204, 



