This Programme I have thought well to reprint for two reasons:—the one being that readers may, from time to time, be able to ascertain what topics are next to be dealt with; the other being that an outline of the scheme may remain, in case it should never be completed.
The successive instalments of which this volume consists, were issued to the subscribers at the following dates:—Part I. (pp. 1–80) in October, 1860; Part II. (pp. 81–176) in January, 1861; Part III. (pp. 177–256) in April, 1861; Part IV. (pp. 257–334) in October, 1861; Part V. (pp. 335–416) in March, 1862; and Part VI. (pp. 417–504) in June, 1862.
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.
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.
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.
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.