The "length of life is dependent upon the number

[1] The _Descent of Man._

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of generations of somatic cells which can succeed one another in

the course of a single life, and furthermore the number as well

as the duration of each single cell-generation is predestined in

the germ itself."[1]

Only in the vague conception of a harmonising or formative

structural influence derived from the germ, perishing in each

cell from internal causes, but handed from cell to cell till the

formative influence itself degrades into molecular discords, does

it seem possible to form any physical representation of the

successive events of life. The degradation of the molecular

formative influence might be supposed involved in its frequent

transference according to some such dynamic actions as occur in

inanimate nature. Thus, ultimately, to the waste within the cell,

to the presence of a force retardative of its perpetual harmonic

motions, the death of the individual is to be ascribed. Perhaps

in protoplasmic waste the existence of a universal death should

be recognised. It is here we seem to touch inanimate nature; and

we are led back to a former conclusion that the organism in its

unconstrained state is to be regarded as a contrivance for

evading the dynamic tendencies of actions in which lifeless

matter participates.[2]

[1] Weismann, _Life and Death; Biological Memoirs_, p. 146.

[2] In connection with the predestinating power and possible

complexity of the germ, it is instructive to reflect on the very

great molecular population of even the smallest spores--giving

rise to very simple forms. Thus, the spores of the unicellular

Schizomycetes are estimated to dimensions as low as 1/10,000 of a

millimetre in diameter (Cornil et Babes, _Les Batteries_, 1. 37).

From Lord Kelvin's estimate of the number of molecules in water,

comprised within the length of a wave-length of yellow light

(_The Size of Atoms_, Proc. R. I., vol. x., p. 185) it is

probable that such spores contain some 500,000 molecules, while

one hundred molecules range along a diameter.

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