ON THE NATURE OF LIFE. 191 



always be in contact with pabulum ; and if the rate of these 

 changes is reduced beyond a certain point, the chemical affin- 

 ities of the materials will at once assert themselves, and the 

 whole will break down into more or less stable chemical com- 

 binations " (p. 5). 



This may be: but we must remember that the 

 living matter has also long intervals of a resting stage, 

 or even a state of suspended animation. In seeds, 

 also, and germs, life seems dormant for long periods, 

 and all change is reduced to a minimum. What that 

 minimum may be we know not, for the rest is never 

 absolute, and Dr. Beale remarks that some change, 

 however slow, must be going on as long as life lasts. 

 I do not attach much weight to any speculative 

 opinions on these points. 



With respect to the physical condition of the living 

 matter, the molecules themselves must be constituted 

 by atomic combination into the vital or metabolic 

 state, but no part or organ, or probably even single 

 plastid, is composed of molecules of only one kind, as 

 is the case with crystals. Hence the different mole- 

 cules which make up every mass having its specific 

 vital attributes, must be connected by cohesive force, 

 although slight ; and it is a fundamental fact that life 

 does not exist in matter in the gaseous or liquid, but 

 exclusively in the solid state. The apparent exception, 

 of the blood, lymph, and other fluids is easily explained 

 by the presence of floating masses of living solids in 

 them. But this solid state is very peculiar and one 

 that admits of the interpenetration of a large quantity 

 of water, without dissociation of the molecules into 

 that free and mobile state which constitutes liquidity. 



