Category: Science - Biology

The Factors of Organic Evolution

The two parts of which this Essay consists, originally published in _The Nineteenth Century_ for April and May 1886 respectively, now reappear with the assent of the proprietor and editor of that periodical, to whom my thanks are due for his courtesy in giving it. Some passage...

Chapters

5. Part 5

Though it does not personalize the cause, and does not assimilate its mode of working to a human mode of working, kindred objections may be urged against the expression to which...

2. Part 2

When discussing the question more than twenty years ago (_Principles of Biology_, § 166), I instanced the decreased size of the jaws in the civilized races of mankind, as a chan...

7. Part 7

Take a small india-rubber ball—not of the inflated kind, nor of the solid kind, but of the kind about an inch or so in diameter with a small hole through which, under pressure,...

4. Part 4

“In many cases there is reason to believe that the lessened use of various organs has affected the corresponding parts in the offspring. But there is no good evidence that this...

3. Part 3

“Changes of any kind in the conditions of life, even extremely slight changes, often suffice to cause variability.... Animals and plants continue to be variable for an immense p...

6. Part 6

A remarkable analogy remains to be named. When we study the action of the medium in an inorganic mass, we are led to see that between the outer changed layer and the inner uncha...

1. Part 1

The two parts of which this Essay consists, originally published in _The Nineteenth Century_ for April and May 1886 respectively, now reappear with the assent of the proprietor...

8. Part 8

It is true that while not deliberately admitted by Mr. Darwin, these effects are not denied by him. In his _Animals and Plants under Domestication_ (vol. ii, 281), he refers to...