upon this point and now upon that, as each is made the securely-fastened point of attachment for the next. The great distinction between the reasonings, say of the metaphysician and the man of science, consists, not in any difference of degree, but in a difference of subject matter. For, while the man whom our author calls the "man of reasoning" has no other test by which to estimate the accuracy of his conclusions than the subjective processes of reason itself, "the man of observation" has the uncompromising court of objective fact whither to bring his conclusions for a trial that is sure to be remorseless, and for a judgment from which there can be no appeal. And because the court of Nature is alone infallible, the man of science shows his wisdom as a seeker of truth by directing his best faculties of thought toward the arguing of his case in such a way that the judgment of this court upon the issue presented shall be final. The issue is that concerning the truth of a laboriously reasoned hypothesis; the argument is a perhaps no less laboriously reasoned experiment; and the judgment is either a triumphant verification or a crushing non-suit with costs—the latter being now happily to some extent defrayed by government. In a word, to disparage those faculties of mind which elaborate scientific generalization, as contrasted with those which elaborate philosophic speculation, is surely too preposterously absurd to be entertained even by the most benighted reader of the "Edinburgh" or any other Review.
The author of this attempt appears, from the authoritative style in which he writes, to regard himself as among the favored "men of reasoning, prone to speculation rather than to experiment." That he would be "comparatively unfitted for the more matter-of-fact employment of investigation and research," we can not entertain the shadow of a doubt, and therefore I see no reason why we should hesitate to place him in the category of those who are "accustomed to deal with the suggestions of the mind," without condescending to bring these suggestions to the test of fact. If so, I grieve to observe that in this case the suggestions of the mind have certainly been of a most unfortunate character.
He first briefly considers the present balance of authority regarding the question of spontaneous generation, or the development of living from non-living matter. On this subject I have no remark to make, except that, so far as the doctrine of evolution is concerned, there is no a priori reason to anticipate the occurrence of spontaneous generation within the limits of time that are possible to human observation. Miserably small as is our knowledge of protoplasm, we at least know enough to be astounded at its enormously complex chemical constitution, and the no less enormously complex physical properties with which it is endowed. The numerous species of elaborately sculptured shells which owe their varied and intricate forms to the vital activities of protoplasm; the fact that all cells, and therefore all
