The same precautions are to be repeated in the identification of electricity with irritability; and the power of depth, for which we have yet no appropriated term, with sensibility. How great the distance is in all, and that the lowest degrees are adopted as the exponent terms, not for their own sakes, but merely because they may be used with less hazard of diverting the attention from the _kind_ by peculiar properties arising out of the degree, is evident from the third instance, unless the theorist can be supposed insane enough to apply sensation in good earnest to the effervescence of an acid or an alkali, or to sympathise with the distresses of a vat of new beer when it is working. In whatever way the subject could be treated, it must have remained unintelligible to men who, if they think of space at all, abstract their notion of it from the contents of an exhausted receiver. With this, and with an ether, such men may work wonders; as what, indeed, cannot be done with a plenum and a vacuum, when a theorist has privileged himself to assume the one, or the other, _ad libitum_?—in all innocence of heart, and undisturbed by the reflection that the two things cannot both be true. That both time and space are mere abstractions I am well aware; but I know with equal certainty that what is _expressed_ by them as the _identity_ of both is the highest reality, and the root of all power, the power to suffer, as well as the power to act. However mere an _ens logicum_ space may be, the _dimensions_ of space are real, and the works of Galileo, in more than one elegant passage, prove with what awe and amazement they fill the mind that worthily contemplates them. Dismissing, therefore, all facts of degrees, as introduced merely for the purposes of illustration, I would make as little reference as possible to the magnet, the charged phial, or the processes of the laboratory, and designate the three powers in the process of our animal life, each by two co-relative terms, the one expressing the _form_, and the other the _object_ and _product_ of the power. My hypothesis will, therefore, be thus expressed, that the constituent forces of life in the human living body are—first, the power of length, or REPRODUCTION; second, the power of surface (that is, length and breadth), or IRRITABILITY; third, the power of depth, or SENSIBILITY. With this observation I may conclude these remarks, only reminding the reader that Life itself is neither of these separately, but the copula of all three—that Life, _as_ Life, supposes a positive or universal principle in Nature, with a negative principle in every particular animal, the latter, or limitative power, constantly acting to individualize, and, as it were, _figure_ the former. _Thus_, then, Life itself is not a _thing_—a self-subsistent _hypostasis_—but an _act_ and _process_; which, pitiable as the prejudice will appear to the _forts esprits_, is a great deal more