96 EVOLUTION THE RESULT OF CHEMICAL FORCES. 



same ratio between the two (10.6) as silver with at. wt. 108 and 

 sp. gr. 10.4 (ratio 10.4) and gold, at. wt. 197, sp. gr. 19.3 (ratio 

 10.2). If we take into account the comparative bulk of such 

 weights of substances as are represented by their atomic weights, 

 the correspondence is complete' all through the list ; * showing 

 that all ultimate particles in solids occupy very nearly the same 

 space. 



Now if it is really true that the last divisions of matter are 

 all of about the same bulk, then the molecule of albumen, con- 

 taining over 600 atoms and weighing more than 6000 times as 

 much as the atom of hydrogen, is not essentially larger than that 

 or any other atom. We can thus see what a tremendous amount 

 of energy must be concentrated in the exceedingly minute mole- 

 cule of the substance which makes up our lives. We can also 

 see how readily may be explained, as for instance by the addition 

 of an atom or the change of place of an atom, the infinite vari- 

 ations in life-forces that are necessary to account for all the 

 infinite varieties of individuals or species or families of the 

 organic kingdoms. 



From the fact that all organic substances are formed on the 

 same complex pattern as albumen, with carbon for their base, and 

 that the nearer to the seat of life these compounds are found, the 

 more complex they are, we are fully justified in concluding that 

 the remarkable property which only carbon possesses of joining 

 together its atoms in one molecule apparently without limit, is 

 the true cause and condition of life. The carbon compounds 

 that take active part in the life-processes never crystallize, but 

 assume always when active the peculiar plastic condition known 

 as the colloid, in which the dynamic forces, whether of the atoms 

 in the molecule, or the molecules in the cell, or the cells in the 

 organism, have full and free course to accumulate, and as we know 

 do amount in the case of large sized animals to a very great sum 

 of energy. 



The constant repetition of muscular acts, or the practice of 

 any skill or cunning, or the exercise of the memory or the per- 

 ceptions or the reasoning faculties, become after a time habits, 



* See full tables in "Miller's Chemistry," Part 3rd, page 957. 



