Hi ON THE PHYSICAL BASIS OF LIFE 145 



special modifications of the fundamental substance. 

 The mineral, carbonate of lime, assumes an 

 immense diversity of characters, though no one 

 doubts that, under all these Protean changes, it is 

 one and the same thing. 



And now, what is the ultimate fate, and what 

 the origin, of the matter of life ? 



Is it, as some of the older naturalists supposed, 

 diffused throughout the universe in molecules, 

 which are indestructible and unchangeable in 

 themselves ; but, in endless transmigration, unite 

 in innumerable permutations, into the diversified 

 forms of life we know ? Or, is the matter of life 

 composed of ordinary matter, differing from it only 

 in the manner in which its atoms are aggregated ? 

 Is it built up of ordinary matter, and again resolved 

 into ordinary matter when its work is done ? 



Modern science does not hesitate a moment 

 between these alternatives. Physiology writes 

 over the portals of life 



"Debemur morti nos nostraque," 



with a profounder meaning than the Roman poet 

 attached to that melancholy line. Under what- 

 ever disguise it takes refuge, whether fungus or 

 oak, worm or man, the living protoplasm not only 

 ultimately dies and is resolved into its mineral 

 and lifeless constituents, but is always dying, and, 

 strange as the paradox may sound, could not live 

 unless it died. 



VOL. I L 



