[54] Id. ii. p. 59.
[55] Insecta Maderensia, pp. 260, 261.
[56] Vide supra, p. 5.
[57] Although, in our ignorance of their real nature, we cannot cite them as actually analogous to these separate phases in certain members of the Insecta, yet we are forcibly reminded by the latter of the distinct states which many of the Terrestrial Mollusca present (frequently in equal proportions) in the same localities. Thus, most of the Pupæ have at least two abruptly-marked forms,—a larger and smaller one. Many of the Helices also exhibit this tendency in an eminent degree: I have indeed been shown specimens by Sir Charles Lyell of the Helix hirsuta, Say, from North America, one state of which is considerably more than double the dimensions of the other; and I believe it is a well-known fact that intermediate links have not yet been observed to connect the extremes. May not therefore the gigantic H. Lowei and Bowdichiana, which are now extinct in the Madeira Islands, have been but forms of the H. Portosanctana and punctulata, respectively,—co-existent with them, though more sensitive to the great diminutions of altitude and area which were consequent on the breaking-up of a once continuous land? If such be the case, however, it is certain that they were far commoner at an early period than their smaller colleagues (which, now, in their proper districts, absolutely teem),—seeing that the latter are extremely rare in the fossil deposits, whilst they themselves literally abound.
[58] Insecta Maderensia, p. 78.
[59] Insecta Maderensia, pp. 21, 22.
CHAPTER V.
GEOLOGICAL REFLECTIONS.
We frequently hear it asserted, that, since the members of the Insecta are so numerous and minute, when compared with those of other departments of the organic world, the entomologist, whose province it is to collect and classify them, can have but little time, if he attempt the real advancement of his particular science, for generalizations on a broad scale. Now, whilst there is necessarily some reason in this remark (for the investigation of species is a work of such labour and drudgery that it is apt to monopolize all the leisure hours which the greater number of us are able to command), we should recollect, on the other hand, that the soundest theorists have ever been the most patient and accurate observers; and have, many of them, spent whole years of their lives as humble students in Nature's domain. We need not be afraid that an occupation amongst what is microscopically small is liable to cramp the mind, and render it unfit for wider processes of induction, since the very opposite of this would seem to come nearer to the truth. The understanding which has been well tutored by a system of close and steady observation, which has been trained to seize upon differences amongst the objects of our common experience, to balance the importance of generic and specific characters, as tested in the acquisitions of our daily walks; and which has been gradually brightened and matured by the habitual exercise of its judgment on the most trifling phænomena around us, has usually gained strength enough to form conclusions from such data, which will not only stand the test of analysis, but will be free from those eccentricities of genius which too often mar the speculations of less practical naturalists. The mind, moreover, having been chained and fettered for a season to the mere detail of facts, breaks forth, under such circumstances, with all the vigour with which the contemplation of truth has gifted it, and takes its flight as it were to a clearer sky; and, though a reaction may at times set in, hurrying it away into regions beyond its sphere, it will assuredly return at length, fraught with the soberness which its vocation has inspired, and commence to build up its hypotheses, step by step, in harmony with the material which it has amassed.