v.] VALUE OF NATURAL HISTORY SCIENCES. 65 



Nor is this all. For after a series of such divisions and sub 

 divisions, these minute points assume a totally new form, lose 

 their long tails round themselves, and secrete a sort of envelope 

 or box, in which they remain shut up for a time, eventually to 

 resume, directly or indirectly, their primitive mode of existence. 



Now, so far as we know, there is no natural limit to the exist 

 ence of the Euglena, or of any other living germ. A living 

 species once launched into existence tends to live for ever. 



Consider how widely different this living particle is from the 

 dead atoms with which the physicist and chemist have to do ! 



The particle of gold falls to the bottom and rests the particle 

 of dead protein decomposes and disappears it also rests : but 

 the living protein mass neither tends to exhaustion of its forces 

 nor to any permanency of form, but is essentially distinguished 

 as a disturber of equilibrium so far as force is concerned, as 

 undergoing continual metamorphosis and change, in point of form. 



Tendency to equilibrium of force and to permanency of form, 

 then, are the characters of that portion of the universe which 

 does not live the domain of the chemist and physicist. 



Tendency to disturb existing equilibrium to take on forms 

 which succeed one another in definite cycles is the character of 

 the living world. 



What is the cause of this wonderful difference between the 

 dead particle and the living particle of matter appearing in other 

 respects identical ? that difference to which we give the name 

 of Life ? 



I, for one, cannot tell you. It may be that, by and by, philo 

 sophers will discover some higher laws of which the facts of life 

 are particular cases very possibly they will find out some bond 

 between physico-chemical phenomena on the one hand, and 

 vital phenomena on the other. At present, however, we 

 assuredly know of none ; and I think we shall exercise a wise 

 humility in confessing that, for us at least, this successive 

 assumption of different states (external conditions remaining the 

 same) this spontaneity of action if I may use a term which 

 implies more than I would be answerable for which constitutes 



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