1
One of these generalizations is that currently known as “the Conservation of Force;” a second may be gathered from a published essay on “Progress: its Law and Cause;” a third is indicated in a paper on “Transcendental Physiology;” and there are several others.
2
The ideas to be developed in the second volume of the Principles of Biology the writer has already briefly expressed in sundry Review-Articles. Part IV. will work out a doctrine suggested in a paper on “The Laws of Organic Form,” published in the Medico-Chirurgical Review for January, 1859. The germ of Part V. is contained in the essay on “Transcendental Physiology:” See Essays, pp. 280–90. And in Part VI. will be unfolded certain views crudely expressed in a “Theory of Population,” published in the Westminster Review for April, 1852.
3
Respecting the several additions to be made to the Principles of Psychology, it seems needful only to say that Part V. is the unwritten division named in the preface to that work – a division of which the germ is contained in a note on page 544, and of which the scope has since been more definitely stated in a paper in the Medico-Chirurgical Review for Jan. 1859.
4
Of this treatise on Sociology a few small fragments may be found in already-published essays. Some of the ideas to be developed in Part II. are indicated in an article on “The Social Organism,” contained in the last number of the Westminster Review; those which Part V. will work out, may be gathered from the first half of a paper written some years since on “Manners and Fashion;” of Part VIII. the germs are contained in an article on the “Genesis of Science;” two papers on “The Origin and Function of Music” and “The Philosophy of Style,” contain some ideas to be embodied in Part IX.; and from a criticism of Mr. Bain’s work on “The Emotions and the Will,” in the last number of the Medico-Chirurgical Review, the central idea to be developed in Part X. may be inferred.
5
Part IV. of the Principles of Morality will be co-extensive (though not identical) with the first half of the writer’s Social Statics.
6
Those who may have before met with this term, will perceive that it is here used in quite a different sense.
7
These extracts are from an article entitled “Nature and God,” published in the National Review for October, 1860.