THE ORGANISM AS A NATURAL THING 9 



whatever it may look like, it is still the homogeneous chemical 

 substance CaCOg. Diamond, the deposit on the inside of a 

 gas-retort and the substance of a black-lead pencil are all 

 carbon. 



Many kinds of inanimate things are characterized by their 

 forms and their chemical compositions. Thus calcite is calcium 

 carbonate that has crystallized in rhomboidal form. All crystals 

 have both form and chemical composition, both essential to their 

 nature. Crystals may have the same form but different chemical 

 composition — if so they are not the same things. Crystals are 

 usually formed and homogeneous. 



Inanimate things may have characteristic forms that are not 

 determined by their composition and which persist even though 

 the materials of which they are composed do not persist. Thus 

 a cyclonic storm is an eddy in the atmosphere and a whirlpool 

 is an eddy in water. The form of the whirlpool may persist 

 although the water of which it is composed changes from second 

 to second. Such things are material fluxes. 



4. ON ORGANISMS AS NATURAL THINGS 



There is a modern " organic theory of nature " in which the 

 term " organism " has been applied to things that are composed 

 of parts and in which these parts have definite relationships to 

 each other so that they make up complex things that have 

 individualities. 



Thus an atom is an '' organism " in this sense, being composed 

 of a system of electrons constituted in a certain way ; 



A molecule is a definite arrangement, in space, of atoms ; 



A colloidal particle is an orderly assemblage of molecules ; 

 and so on. 



But an atom has not always been the same thing. Before 1890 

 it was a perfectly hard, perfectly elastic, finite but indivisible 

 particle ; J.J. Thomson's atom was a sphere of positive electricity 

 in which negative electrons were embedded ; Bohr's atom was a 

 system composed of a positively charged nucleus round which 

 revolved satellite electrons in definite orbits. We may regard 

 the atom as being constituted by protons that form a nucleus. 

 There are " atmospheric " electrons outside the nucleus, but the 

 inner electrons occupy w^hole orbits rather than revolve in orbits, 



