practice and familiarity may have exhausted its powers of attention to all the stages of its own performance, just as a practised workman in building a wall certainly does not consciously follow all the processes which he goes through. As an example, however, of the extreme dislike which philosophers of a certain school have for making the admissions which seem somewhat grudgingly conceded by Dr. Carpenter, we may take the paragraph which immediately follows the ones which we have just quoted. Dr. Carpenter there writes:— “The writer has often amused himself and others, when by the seaside, with getting a _terebella_ (a marine worm that cases its body in a sandy tube) out of its house, and then, putting it into a saucer of water with a supply of sand and comminuted shell, watching its appropriation of these materials in constructing a new tube. The extended tentacles soon spread themselves over the bottom of the saucer and lay hold of whatever comes in their way, ‘all being fish that comes to their net,’ and in half an hour or thereabouts the new house is finished, though on a very rude and artificial type. Now here the organisation is far higher; the instrumentality obviously serves the needs of the animal and suffices for them; and we characterise the action, on account of its uniformity and apparent _un_intelligence, as instinctive.” No comment will, one would think, be necessary to make the reader feel that the difference between the terebella and the amœba is one of degree rather than kind, and that if the action of the second is as conscious and reasonable as that, we will say, of a bird making her nest, the action of the first should be so also. It is only a question of being a little less skilful, or more so, but skill and intelligence would seem present in both cases. Moreover, it is more clever of the terebella to have made itself the limbs with which it can work, than of the amœba to be able to work without the limbs; and perhaps it is more sensible also to want a less elaborate dwelling, provided it is sufficient for practical purposes. But whether the terebella be less intelligent than the amœba or not, it does quite enough to establish its claim to intelligence of a higher order; and one does not see ground for the satisfaction which Dr. Carpenter appears to find at having, as it were, taken the taste of the amœba’s performance out of our mouth, by setting us about the less elaborate performance of the terebella, which he thinks we can call unintelligent and instinctive.