a fight; yet the scent of an unknown dog must arouse in his mind, not the idea of any dog in particular, but an idea of the animal Dog in general. Thus far, it will be remembered, I have been presenting evidence in favour of the view that both infants and animals show themselves capable of forming general ideas of a simple order, and, therefore, that to the formation of such ideas the use of language is not essential. I will next consider what has to be said on the other side of the question; for, as previously remarked, many—I may say most—psychologists repudiate this kind of evidence _in toto_, as not germain to the subject of debate. First, therefore, I will consider their objections to this kind of evidence; next I will sum up the whole question; and, lastly, I will suggest a classification of ideas which in my opinion ought to be accepted by both sides as constituting a common ground of reconciliation. To begin with another quotation from Locke, “How far brutes partake in this faculty [_i.e._ that of comparing ideas] is not easy to determine; I imagine they have it not in any great degree: for though they probably have several ideas distinct enough, yet it seems to me to be the prerogative of human understanding, when it has sufficiently distinguished any ideas, so as to perceive them to be perfectly different, and so consequently two, to cast about and consider in what circumstances they are capable to be compared: and therefore I think beasts compare not their ideas further than some sensible circumstances annexed to the objects themselves. The other power of comparing, which may be observed in men, belonging to general ideas, and useful only to abstract reasonings, we may probably conjecture beasts have not. “The next operation we may observe in the mind about its ideas, is composition; whereby it puts together several of those simple ones it has received from sensation and reflection, and combines them into complex ones. Under this head of composition may be reckoned also that of enlarging; wherein, though the composition does not so much appear as in more complex ones, yet it is nevertheless a putting several ideas together, though of the same kind. Thus, by adding several units together, we make the idea of a dozen; and by putting together the repeated ideas of several perches, we frame that of a furlong.