M ONER A, AND THE PROBLEM OF LIFE. 567 



It is for the sake of a somewhat commensurate appreciation of 

 vitality, of high-wrought molecular organization, that it is necessary, 

 again and again, to point out the might of potentiality intrinsic to 

 matter, the vast and specific stores of force locked up in the peculiar 

 molecular entanglements which constitute our different substances. 

 All forms of matter are essentially magazines of equilibrated energies : 

 inert against such other energies as have no power to disturb their 

 equilibrium, but seething with incalculable commotion against such 

 other energies as have power to disturb their equilibrium. 



What H Q is to the steam-engine, the moving substance, the pro- 

 toplasm, is to the living engine. Machinery is fastened on to both 

 these motor powers exactly in the same manner. The expansion and 

 contraction of H 2 give motion to the prearranged and molecularly 

 unyielding levers of the steam-engine. The expansion and contraction 

 of the protoplasm give motion to the prearranged and molecularly 

 unyielding levers of the animal engine. We see the correspondence 

 between an engine and a higher organism is even more complete than 

 is generally conceived by philosophers of the purely mechanical school. 



Only, the specific power of the slightly complicated molecule H 2 

 cannot possibly afford any standard for the estimation of the specific 

 power of the immensely more complicated molecule constituting proto- 

 plasm. Protoplasm differs from water in proportion to its synthetical 

 wealth. Whatever synthetical wealth may be the symbol of, in its 

 gradations is to be sought the source of all difference in Nature. This 

 is the gist of what chemistry teaches : the work of Nature consists in 

 molecular synthesis. It has required the ceaseless toil of endless ages 

 to build up the molecule of living matter. Let us then value it accord- 

 ingly, and nevermore view it under the degrading aspect of stolid 

 machinery. 



Motility, then, consists in the alternate expansion and contraction 

 of protoplasm, which expansion and contraction are incited by a process 

 of chemical composition and decomposition occurring within the pro- 

 toplasm. The property of occupying so much more or so much less 

 space, under these different conditions, belongs entirely to the respec- 

 tive organic substances, which alternately fill the larger and the smaller 

 space. The forces which are brought into activity during the process 

 are forces of a known kind, but essentially inherent in the living sub- 

 stance. They are stimulated, not transferred. They are a display of 

 intrinsic power, not an application of extrinsic power. They are not 

 the heat of combustion pushing together or dragging asunder the 

 molecules of the organic substance ; they are part of the expression, 

 i. e., of the influence on the medium, of those most specific chemical 

 affinities which synthetical elaboration has ingrained into the constitu- 

 tion of the protoplasm. 



If, in contemplating this truth, so positively disclosed by the study 

 of living matter, it should become evident that the display of all other 



