Here we have touched on the second essential element of language. We laid it down, that its essence lay in the communication of an idea from one intelligent being to another; but no ideas can be communicated at all except by the aid of conventions to which both parties have agreed to attach an identical meaning. The agreement may be very informal, and may pass so unconsciously from one generation to another that its existence can only be recognized by the aid of much introspection, but it will be always there. A sayer, a sayee, and a convention, no matter what, agreed upon between them as inseparably attached to the idea which it is intended to convey--these comprise all the essentials of language. Where these are present there is language; where any of them are wanting there is no language. It is not necessary for the sayee to be able to speak and become a sayer. If he comprehends the sayer-- that is to say, if he attaches the same meaning to a certain symbol as the sayer does--if he is a party to the bargain whereby it is agreed upon by both that any given symbol shall be attached invariably to a certain idea, so that in virtue of the principle of associated ideas the symbol shall never be present without immediately carrying the idea along with it, then all the essentials of language are complied with, and there has been true speech though never a word was spoken. The lower animals, therefore, many of them, possess a part of our own language, though they cannot speak it, and hence do not possess it so fully as we do. They cannot say "bread," "meat," or "water," but there are many that readily learn what ideas they ought to attach to these symbols when they are presented to them. It is idle to say that a cat does not know what the cat's-meat man means when he says "meat." The cat knows just as well, neither better nor worse than the cat's-meat man does, and a great deal better than I myself understand much that is said by some very clever people at Oxford or Cambridge. There is more true employment of language, more bona fide currency of speech, between a sayer and a sayee who understand each other, though neither of them can speak a word, than between a sayer who can speak with the tongues of men and of angels without being clear about his own meaning, and a sayee who can himself utter the same words, but who is only in imperfect agreement with the sayer as to the ideas which the words or symbols that he utters are intended to convey. The nature of the symbols counts for nothing; the gist of the matter is in the perfect harmony between sayer and sayee as to the significance that is to be associated with them.