crete facts, then, so far as I perceive, we are able to make no advance. For as to that which can, and that which cannot, play the part of an organism, we know very little. A sameness greater or less with our own bodies is the basis from which we conclude to other bodies and souls. And what this inference loses in exactitude (Chapter xxi.), it gains on the other hand in extent, by acquiring a greater range of application. And it would seem almost impossible, from this ground, to produce a satisfactory negative result. A certain likeness of outward form, and again some amount of similarity in action, are what we stand on when we argue to psychical life. But our failure, on the other side, to discover these symptoms is no sufficient warrant for positive denial.[1] There may surely beyond our knowledge be strange arrangements of qualities, which serve as the condition of unknown personal unities. Given a certain degree of difference in the outward form, and a certain divergence in the way of manifestation, and we should fail at once to perceive the presence of an organism. But would it, therefore, always not exist? Or can we assume, because we have found out the nature of some organisms, that we have exhausted that of all? Have we an ascertained essence, outside of which no variation is possible? Any such contention would seem to be indefensible. Every fragment of visible Nature might, so far as is known, serve as part in some organism not like our bodies. And, if we consider further how much of Nature may be hid from our view, we shall surely be still less inclined to dogmatism. For that which we see may be combined in an organic unity with the invisible; and, again, one and the same element might have a position and function in any number of organisms. But there is no advantage in trying to fill the unknown with our fancies. It should be