| Comparison with 1859 |
|
slowly in density, so as to separate into layers of different densities and thicknesses, placed at different distances from each other, and with the surfaces of each layer slowly changing in form. Further we must suppose that there is a power
always
intently watching each slight accidental
alteration in the transparent layers; and carefully selecting
each alteration
which, under varied circumstances, may
in any way,
or in any degree, tend
to produce a distincter image. We must suppose each new state of the instrument to be multiplied by the million; and
each to be preserved till
a better be
produced, and then the old ones to be destroyed. In living bodies, variation will cause the slight alterations, generation will multiply them almost infinitely, and natural selection will pick out with unerring skill each improvement. Let this process go on for millions on millions
of years; and during each year on millions of individuals of many kinds; and may we not believe that a living optical instrument might thus be formed as superior to one of glass, as the works of the Creator are to those of man? ↑| Subtitle not present 1859 1860 1861 |
| Modes
of
Transition. 1866 1869 1872 |
|
| If it could be demonstrated that any complex organ existed, which could not possibly have been formed by numerous, successive, slight modifications, my theory would absolutely break down. But I can find out no such case. No doubt many organs exist of which we do not know the transitional grades, more especially if we look to much-isolated species, round which, according to my
theory, there has been much extinction. Or again, if we look to
an organ common to all the members of a large
class, for in this latter case the organ must have been first
formed at an extremely
remote period, since which all the many members of the class have been developed; and in order to discover the early transitional grades through which the organ has
|
slowly in density, so as to separate into layers of different densities and thicknesses, placed at different distances from each other, and with the surfaces of each layer slowly changing in form. Further we must suppose that there is a
power | power 1859 1860 1861 1866 | | power, 1869 1872 |
| always 1859 1860 |
| (natural selection) always 1861 1866 |
| represented by natural selection or the survival of the fittest, always 1869 1872 |
| accidental 1859 1860 1861 1866 | accidental 1869 1872 |
| selecting 1859 1860 1861 1866 | | preserving 1869 1872 |
| alteration 1859 1860 1861 1866 | alteration 1869 1872 |
| may 1859 1860 1861 1866 | may 1869 1872 |
| way, 1859 1860 1861 1866 | | way 1869 1872 |
| tend 1859 1860 1861 1866 | | tends 1869 1872 |
| and 1859 1860 1861 1866 | and 1869 1872 |
| till 1859 1860 1861 1866 | | until 1869 1872 |
| be 1859 1860 1861 1866 | | one is 1869 1872 |
| destroyed. 1859 1860 1861 1866 | | all destroyed. 1869 1872 |
| on millions 1859 1860 1861 1866 | on millions 1869 1872 |
| Subtitle not present 1859 1860 1861 |
| Modes
of
Transition. 1866 1869 1872 |
|
If it could be demonstrated that any complex organ existed, which could not possibly have been formed by numerous, successive, slight modifications, my theory would absolutely break down. But I can find out no such case. No doubt many organs exist of which we do not know the transitional grades, more especially if we look to much-isolated species, round which, according to
my | my 1859 1860 1861 1866 | | the 1869 1872 |
| look to 1859 1860 1861 1866 | | take 1869 1872 |
| large 1859 1860 1861 1866 1869 | large 1872 |
| first 1859 1860 1861 | | originally 1866 1869 1872 |
| an extremely 1859 1860 1861 1866 1869 | | a 1872 |
|
