v.] EDUCATIONAL VALUE OF NATURAL HISTORY SCIENCES. 75 



will give rise is immense : in the first place it will 

 develop a vast quantity of physical force — cleaving 

 the water in all directions with considerable rapidity 

 by means of the vibrations of the long filament or 

 cilium. 



Nor is the amount of chemical energy which the little 

 creature possesses less striking. It is a perfect laboratory 

 in itself, and it will act and react upon the water and 

 the matters contained, therein ; converting them into new 

 compounds resembling its own substance, and at the 

 same time giving up portions of its own substance which 

 have become effete. 



Furthermore, the Euglena will increase in size ; but 

 this increase is by no means unlimited, as the increase 

 of a crystal might be. After it has grown to a certain 

 extent it divides, and each portion assumes the form of 

 the original, and proceeds to repeat the process of growth 

 and division. 



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

 and subdivisions, 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 existence 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 



