I have been tracing during the last ten years, and show what is likely to be the character of the whole series. I have aimed, therefore, in preparing these two volumes, to combine them in such a manner as that they should form a whole. The First Part contains an exposition of the general views I have arrived at thus far, in my studies of Natural History. The Second Part shows how I have attempted to apply these results to the special study of Zoölogy, taking the order of Testudinata as an example. I believe, that, in America, where turtles are everywhere common, and greatly diversified, a student could not make a better beginning than by a careful perusal of this part, specimens in hand, with constant reference to the second chapter of the First Part. The Third Part exemplifies the bearing of Embryology upon these general questions, while it contains the fullest illustration of the embryonic growth of the Testudinata."
The Preface closes with honorable mention of the gentlemen who have furnished direct assistance in the preparation of the work, and especially of Mr. Clark in microscopic observation and illustration, and of Mr. Sonrel in drawing the zoölogical figures.
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."
Certain general doctrines, the spirit of which runs through all the scientific works of Mr. Agassiz, are distinctly laid down in the first section of this chapter. It is headed with the statement, "The leading features of a natural zoölogical system are all founded in nature." The systems named from the great leaders of science are but translations of the Creator's thoughts into human language. "If it can be proved that man has not invented, but only traced this systematic arrangement in nature,—that these relations and proportions which exist throughout the animal and vegetable world have an intellectual, an ideal connection in the mind of the Creator,—that this plan of creation,
