STILL FOUND IN A LIVING STATE. 329 
eurrence of conditions favourable for organic life and action is 
able to produce in a very short time immense and wholly incon- 
ceivable masses. Thus, according to the above-stated facts and 
laws,— (I trust this last apparent, even when rarely scientifically 
useful, yet inductive play with numbers, will be allowed and 
pardoned me,)—a single animalcule, which can form in four days 
by its siliceous shell the solid mass of two cubic foot of polish- 
ing slate of that stratum near Bilin fourteen foot in depth, may 
have, in only eight days of equally and tranquilly continued un- 
disturbed organic activity, increased to so great a number of in- 
dividuals, that its mass filled the cube of aGerman mile; and fewer 
individual animalcules than are contained in a cubic inch of the 
Bilin polishing slate, in contemporaneous organic activity, fa- 
youred in every respect, would suffice in the same time to afford 
a mass of silica which would equal the size of the earth. All this 
would take place in that period, by an imperceptible Infusorium, 
and the simple act of the organic self-division of each individual 
within one hour after a repose of the same duration. Thus a num- 
ber of small imperceptible drops of rain, disengaged with un- 
usual rapidity and acting collectively, are able to destroy houses 
and hills. How many centuries, then, are requisite to form a bed 
of polishing slate fourteen foot thick near Bilin, or a layer of 
berg-mehl twenty-eight foot thick in the plain of Lunebourg, or 
a layer of chalk some hundred foot thick with alternate infusorial 
marls or substituent strata of flint, needs no further indication. 
It is almost superfluous to observe that he who should call the 
above explanation mere speculation would forget that it is based 
upou experience and observations; and he who might still find 
the phenomena inexplicable and marvellous would forget that 
they are of daily occurrence in the waters surrounding hin, in 
conflict with many other forces quite as gigantic, more frequently 
overcome than overcoming. Whether these beings create car- 
bon, lime, silica, and iron, or merely transform them one into the 
other, it is impossible to say, for the extent of their influence is 
beyond the reach of observation. I cannot deny that these con- 
siderations have acted as incitements to me, not indeed to a hasty 
systematizing, but to a further earnest prosecution of inquiry. 
Self-division, as a mode of increase in the Infusoria, has an- 
other aspect, which is found in no other animal group in a 
degree so decidedly influential, and which is of peculiar import- 
ance as regards the fossil relations here to be explained. Whilst 
in organic nature, not merely in the larger organisms, but in all 
VOL, Ill. PART x. Zz 
