The first change signalized in the impregnated egg seems that of _Furchung_, or furrowing—what the Germans call the _Furchungskugeln_, the _Dotterkugeln_, form. Then these _Kugeln_—clumps, eminences, monticles, we may translate the word—break into cells; and these are the cells of the embryo. Mr. Huxley, as quoted, refers to the whole body, and every organ of the body, as at first but an aggregation of colorless blood-corpuscles; but in the very statement which would render the identity alone explicit, the difference is quite as plainly implicit. As much as this lies in the word “organs,” to say nothing of “human.” The cells of the “organs,” to which he refers, are even then uninterchangeable, and produce but themselves. The Germans tell us of the _Keimblatt_, the germ-leaf, in which all these organs originate. This _Blatt_, or leaf, is threefold, it seems; but even these folds are not indifferent. The various cells have their distinct places in them from the first. While what in this connection are called the epithelial and endorthelial tissues spring respectively from the _upper_ and _under_ leaf, connective tissues, with muscle and blood, spring from the _middle_ one. Surely in such facts we have a perfect warrant to assert the initial non-identity of protoplasm, and to insist on this, that, from the very earliest moment—even literally _ab ovo_—brain-cells only generate brain-cells, bone-cells bone-cells, and so on. These considerations on function all concern faculty or power; but we have to notice now that the characteristic and fundamental form of power is to Mr. Huxley _contractility_. He even quotes Goethe in proof of contractility being the main power or faculty of _Man_! Nevertheless it is to be said at once that, while there are differences in what protoplasm _is_ contractile, all protoplasm is not contractile, nor dependent on contractility for its functions. In the former respect, for example, muscle, while it is the contractile tissue special, is also to Mr. Huxley protoplasm; yet Stricker asserts the inner construction of the contractile substance, of which muscle-fibre virtually consists, to be essentially different from contractile protoplasm. Here, then, we have the contractile _substance_ proper “essentially different” from the contractile _source_ proper. In the latter respect, again, we shall not call in the _un_contractible substances which Mr. Huxley himself denominates protoplasm—bread, namely, roast mutton, and boiled lobster; but we may ask where—even in the case of a living body—is the contractility of white of egg? In this reference, too, we may remark that Kühne, who divides the protoplasm of the epidermis into three classes, has been unable to distinguish contractility in his own third class. Lastly, where, in relation to the protoplasm of the nervous system, is there evidence of its contractility? Has any one pretended that thought is but the contraction of the brain; or is it by