In this extension of language by the child we may discern, along with this play of the feeling for similarity, the working of association. This is illustrated by the case of Darwin’s grandchild, who when just beginning to speak used the common sign ‘quack’ for duck, then extended this to water, then, following up this associative transference by a double process of generalisation, made the sound serve as the name of all birds and insects on the one hand, and all fluid substances on the other.[93] ----- Footnote 93: Quoted by Romanes, _Mental Evolution in Man_, p. 283. ----- The transference of the name ‘quack’ from the animal to the water is a striking example of the tendency of the young mind to view things which are presented together as belonging one to another and in a manner identical. Another curious instance is given by Professor Minto, in which a child, who applied the word ‘mambro’ to her nurse, went on to extend it by associative transference to the nurse’s sewing machine, then by analogy applied it to a hand-organ in the street, later on, through an association of hand-organ with monkey, to his india-rubber monkey. Here we have a whole history of change of word-meaning illustrating in curiously equal measure the play of assimilation and of association, and falling within a period of two years.[94] ----- Footnote 94: _Logic_ (University Extension Manuals), pp. 83-84. ----- There is another way in which children are said to ‘extend’ names somewhat analogous to the processes of assimilation and associate transference. They are very fond of using the same word for opposed or other correlative ideas. In some cases we can see that this is due merely to confusion or want of discrimination. When, for example, Preyer’s boy confused ‘too little’ with ‘too much,’ and ‘yesterday’ with ‘to-morrow,’ going so far as to make a compound ‘heitgestern’ (_i.e._, heutegestern) to include both,[95] it is easy to see that the child’s mind had reached merely the vague idea unsuitable in quantity in the one case, and time not present in the other; and that he failed to differentiate these ideas. In other cases where correlatives are confused, as when a child extended the sign of asking for an eatable (‘bit-ye’) to the act of offering anything to another, or when as in C.’s case ‘spend’ was made to do duty for ‘cost,’ ‘borrow’ for ‘lend,’ and ‘learn’ for ‘teach,’ the explanation is slightly different. A child can only acquire an idea of abstract relations slowly and by stages. Such words as _lend_, _teach_, call up first a pictorial idea of an action in which two persons are seen to be concerned. But the exact nature of the relation, and the difference in its aspect as we start from the one or the other term, are not perceived. Thus in thinking of a purchase over the counter, a child may be supposed to image the action but not clearly to distinguish the part taken by the person who buys and