However little value may now be attached to these theories, without a due consideration of them, we can neither appreciate some of the best of Lamarck’s writings, nor understand the character of the man himself. In his own eyes, they appeared of paramount importance. The most practically useful of his zoological and botanical works he regarded as trivial in comparison. He conceived them to present a key to some of the most secret operations of nature, and to afford the means of placing many branches of knowledge on a new foundation. This ardent attachment to views which have so generally been considered extravagant and untenable, may seem surprising in the case of an individual whom all must acknowledge to be possessed of much acuteness and discrimination. It is perhaps to be accounted for by their being nursed in the long solitudes to which his bad health and limited circumstances frequently confined him, without having his eyes opened to their fallacies by a discussion of their merits, or interchange of thought with others: for ’Tis thought’s exchange, which, like the alternate rush Of waves conflicting, breaks the learned scum, And defecates the student’s standing pool; By that untutor’d, contemplation raves, And nature’s fool by wisdom is outdone. It may likewise be supposed that he would be unwilling to perceive, or if he did perceive, equally reluctant to acknowledge, the imperfection of systems which he had wrought out with so much care and labour. For that they must have cost him a great degree of laborious thought, will appear from the slightest inspection. It must also be allowed, that they evince a reach of mind, a power of original thinking, and a degree of varied knowledge, calculated to convey no mean idea of his intellectual character. Neither can we deny to them a certain degree of consistency, or adaptation of parts to each other; and although the praise of consistency must be qualified by the admission that it is consistency in error, yet, in such cases, this is of such difficult attainment, as of itself to imply a high degree of acuteness and circumspection. However startling the conclusions to which Lamarck leads us, they are generally drawn by a legitimate and fairly managed process of induction from the assumed premises. But the very extravagance of the conclusions ought to have created a suspicion that the premises were erroneous; and they are, in fact, almost invariably found to be wholly inadmissible.