The LIST OF SUBSCRIBERS is not without its special meaning and interest. If, as has been said, the grade of civilization in any community can be estimated by the amount of sulphuric acid it consumes, the extent to which a work like this has been called for in different sections of the country may to some extent be considered an index of its intellectual aspirations, if not of its actual progress. This is especially true of those remoter regions where personal motives would exercise least influence. But without instituting any comparisons, we may well be proud of this ample list of twenty-five hundred subscribers, most of them citizens of the republic,--"a support such as was never before offered to any scientific man for purely scientific ends, without any reference to government objects or direct practical aims." Our analysis must confine itself mainly to the first of the three parts into which these two volumes are divided. This first part it is that contains those large results which every thinker must desire to learn from one whose life has been devoted to the searching and contemplative study of Nature. It is in the realm of thought here explored, that Natural Science, whose figure we are wont to look down upon, crouching to her task, like him of the muck-rake, as he painfully gathers together his sticks and straws, rises erect, and lifts her forehead into the upper atmosphere of philosophy, where the clouds are indeed thickest, but the stars are nearest. The second and third parts belong more exclusively to the professed students of Natural History in its different special departments. Our notice of these divisions of the work must therefore be comparatively brief. The first chapter of the first part has for its title, "The fundamental relations of animals to one another and to the world in which they live, as the basis of the natural system of animals."