CHAP. VIII 



Vitality 141 



whole earth. • Life itself is dependent upon the invariable 

 presence of minute quantities of iron in the soil. A wan- 

 dering tribe of savages is an organism not quite so high in 

 the scale of social organisms as is the hydra in the scale 

 of individuals ; for the cells of the hydra, although divided 

 broadly into an outer and an inner layer, are yet more 

 divided in their functions than are the members of a 

 savage tribe. For there are only two kinds of person in 

 such a tribe — hunters and cooks ; while a highly civilised 

 community, with its immense variety of workmen, is prob- 

 ably not so well organised as any mammal ; for there are 

 in such a state thousands of persons, untrained to any special 

 labour, merely a burden to themselves and to the nation. 



9. Origin of Life. — We have said that life probably 

 began when the conditions of heat and solubility of sub- 

 stance were more favourable to the formation of peculiar 

 and complex matter than at present. But such a state- 

 ment is often thought to be unphilosophical in view of the 

 fact that we have at present no experience of the formation 

 of such substances, and that it has been conclusively proved 

 that living creatures always proceed from pre-existing life. 

 But those who urge such objections forget that all that has 

 been proved is, that the simplest creatures known to be alive 

 at present can be formed only by cell -division one from 

 another, and not from simple chemical materials. But we 

 must remember that those simplest animals are highly 

 developed in comparison with the complex matter from 

 which we conceive life to have sprung ; and no one 

 would now expect that such comparatively highly developed 

 animals could arise from simple matter. There is certainly 

 no evidence of the formation at present of the very simplest 

 and original living matter. But, in the first place, could 

 we see it, even with a microscope, if it were to be formed ? 

 Might it not be formed molecule by molecule ? And, 

 secondly, what chance of survival would such elementary 

 creatures have among the voracious animals that swarm in 

 all places where such simplest creatures might possibly be 

 formed ? Instantly they would be devoured, before they 

 could grow large enough to be seen. 



