THE ELEMENTS AXl) LIFE 385 



Here only three elements are combined, and in identical pro- 

 portions. We can imagine, therefore, what endless diversities 

 arise when to these are added anv of nine other elements, and 

 these in varying proportions, as Avell as being groii])ed in every 

 possible manner. 



The fact of ^^ isomerism," or of different substances, often 

 with very different properties, having the very same chemical 

 composition, is now so familiar to chemists as to excite com- 

 paratively little attention, yet it is really a marvel and a mys- 

 tery almost equal to that of the organic cell itself. It is 

 probably dependent upon the highly complex nature of the 

 molecules of the elements, and also of the atoms of which these 

 molecules are built up; while atoms themselves are now be- 

 lieved to be complex systems of electrons, which are held to be 

 the units of electricity and of matter. It is these electrons 

 and their mysterious forces that give to matter all its mechan- 

 ical, physical, and chemical properties, including those which, 

 in the highly complex protoplasm, have rendered possible that 

 whole world of life we have been considering in the present 

 volume. 



Here, then, we find, as before, that the further back we go 

 towards the innermost nature of matter, of life, or of mind, 

 we meet with new complications, new forces, new agencies, all 

 pointing in one direction towards the final outcome — the buikl- 

 ing up of a living sentient form, which should be the means 

 of development of the enduring spirit of man. 



Important and Unimportant Elements 



If we look at the long list of between seventy and eighty 

 elements now known we shall see that a comparatively suuill 

 number of these (less than one-fourth) seem to play any im- 

 portant part either in the structure of the earth as a phinet, 

 or in the constitution of the organised l)eings that have been 

 developed upon it. The most important of the elements is 

 oxygen, which is not only an essential in the structure of all 

 living things, but forms a large part of the air and the water 



