LIFE FROM A PHYSICAL STANDPOINT. 17 



signify anything they signify that nothing of the sort should 

 be expected from a substance chemically homogeneous like pre- 

 cipitated albumen, for there is required two differently consti- 

 tuted substances, physically mixed, not chemically combined, 

 and no mere chemical process or chemical product could give 

 such a mixture. It is evident that in a chemically homogeneous 

 mass there can be no occasion for changes of any kind within 

 it, and chemistry alone cannot give us any substance which can 

 give characteristic vital actions. 



It is true enough that the materials with which Butschli has 

 made his observations are not the same as the real substance 

 of living protoplasm, yet they are not so far apart as one at 

 first thought might imagine. Whenever chemical action is 

 taking place, whether fast or slow, these exchanges in the form 

 of energy are likewise taking place, changes from molecular to 

 mechanical motions, from one degree of absorption and con- 

 duction of heat to another, from one degree of condensation 

 to another, and so on, and now let one add to these the quality 

 of atoms, referred to a little way back, namely, that their field 

 of action is not limited to a push or pull by contact, but that it 

 acts at a distance from itself in various ways, and one of these 

 is to compel other masses in its neighborhood to assume the 

 same form and condition as itself that is, the so-called sym- 

 pathetic action. It can be apprehended that when there is 

 energy being expended in this kind of a way we have a proc- 

 ess which is called growth. If the molecules are closely 

 adhesive, as they are in so-called solids, the growth can take 

 place only upon the outer surface, yet even here the growth is 

 limited to the same kind of material as that of the initiating 

 mass ; that is to say, a crystal of salt will only annex salt mole- 

 cules to itself, so, though there be several different substances in 

 a solution capable of crystallizing, each one will select mole- 

 cules of its own kind, and each crystal is similar in kind and 

 structure throughout. This is a kind of natural selection, 

 inherent in the atoms themselves. 



But there is the widest difference in character between the 

 few elements that make up a living thing, from oxygen with 

 communistic instincts to nitrogen with antisocial qualities, and 



