Just as in the case of the gesture-movements, sniffing, kissing, so in that of expressive vocal sounds we may see a tendency to take on the function of true signs of ideas. One of the best illustrations of this is to be found in the invention of a word-sound for things to eat. I have pointed out that the state of hunger with its characteristic misery becomes at an early stage marked off by a distinctive expressive sign. At a later stage this or some other sound comes to be used intelligently as a means of _asking_ for food. Darwin’s boy employed the sound _mum_ in this way; another English child used ‘numby,’ and yet another ‘nini’; a French child observed by M. Taine made use of ‘ham’. The predominance of the labial _m_ shows the early formation of these quasi-linguistic signs, and suggests that they were developed out of the primary instinctive ‘_m_’ sound.[65] Such sounds, coming to be understood by the nurse, tend to become fixed as modes of asking for food. ----- Footnote 65: See the quotation from Lieber, in Taine’s _On Intelligence_, part ii., book iv., chap. i. The sign for ‘I want to eat’ is in some cases formed by a generalising process out of a sound supplied by another, as the name of a particular edible. See the example given by Preyer, _op. cit._, p. 362. ----- It seems but a step from the demand ‘Give me food’ to the pointing out or naming of things as food. And so good an observer as Darwin says that his boy used the sound ‘mum’ not only for conveying the demand or command ‘Give me food,’ but also as a substantive ‘food’ of wide application. He later went on to erect a rudimentary classification on the basis of this substantive, calling sugar ‘shu-mum’ and even breaking up this subdivision by calling liquorice “black shu-mum”.[66] This however seems, so far as I can ascertain, to be exceptional. In most vocabularies of children of two or three no generic term for food is found, though names for particular kinds of food, _e.g._, milk, bread, are in use. This agrees with the general order of development of thought-signs, the names of easily distinguished species appearing in the case of the individual as in that of the race before those of comprehensive and ‘abstract’ genera such as ‘food’. It is probable, therefore, that these early signs for food are but imperfectly developed into true thought-symbols or names. They retain much of their primordial character as expressions of desire and possibly of the volitional state answering to a command. This is borne out by the fact that the child spoken of by Taine used the sound ‘tem’ as a sort of general imperative for ‘give!’ ‘take!’ ‘look!’ etc.[67] ----- Footnote 66: See _Mind_, vol. ii., p. 293. Footnote 67: See _Mind_, vol. ii., p. 255. -----