contraction that the very nerves operate contraction—the nerves that supply muscles, namely? Mr. Huxley himself, in his Physiology, describes nervous action very differently. There _conduction_ is spoken of without a hint of contraction. Of the higher faculties of man I have to speak again; but let us just ask where, in the case of any pure sensation—smell, taste, touch, sound, color—is there proof of any contraction? Are we to suppose that between the physical cause of heat without and the mental sensation of heat within, contraction is anywhere interpolated? Generally, in conclusion here, while reminding of Virchow’s testimony to the inherent inequalities of cell-capacity, let us but, on the question of faculty, contrast the kidney and the brain, even as these organs are viewed by Mr. Huxley. To him the one is but a sieve for the extrusion of refuse: the other thinks Newton’s ‘Principia’ and Iliads of Homer. Probably, then, in regard to any continuity in protoplasm of power, of form, or of substance, we have seen _lacunæ_ enow. Nay, Mr. Huxley himself can be adduced in evidence on the same side. Not rarely do we find in his essay admissions of _probability_ where it is _certainty_ that is alone in place. He says, for example, “It is more than probable that _when_ the vegetable world _is_ thoroughly explored we _shall_ find all plants in possession of the same powers.” When a conclusion is decidedly announced, it is rather disappointing to be told, as here, that the premises are still to collect. “_So far_,” he says again, “as the conditions of the manifestations of the phenomena of contractility have _yet_ been studied.” Now, such a _so far_ need not be _very far_; and we may confess in passing, that from Mr. Huxley the phrase, “the conditions of the _manifestations_ of the _phenomena_” grates. We hear again that it is “the rule _rather_ than the exception,” or that “weighty authorities have _suggested_” that such and such things “probably occur,” or, while contemplating the nettle-sting, that such “_possible_ complexity” in other cases “_dawns_ upon one.” On other occasions he expresses himself to the effect that “perhaps it would not yet be safe to say that _all_ forms,” etc. Nay, not only does he directly _say_ that “it is by no means his intention to suggest that there is no difference between the lowest plant and the highest, or between plants and animals,” but he directly proves what he says, for he demonstrates in plants and animals an _essential difference of power_. Plants _can_ assimilate inorganic matters, animals can _not_, etc. Again, here is a passage in which he is seen to cut his own “_basis_” from beneath his own feet. After telling us that all forms of protoplasm consist of carbon, hydrogen, oxygen, and nitrogen “in very complex union,” he continues, “To this complex combination, _the nature of which has never been determined with exactness_, the name of protein has been applied.” This, plainly, is an identification, on Mr.