Unless there were a clear relation between the anatomy of one animal and that of others, the memory would refuse to burden itself with the details of their structure. So in the study of languages we learn several languages by perceiving their true structural relations, and remembering these. Association of this kind, and the maintenance of order in the mind, are the only arts of memory compatible with the right government of the intellect. Incongruous, and even superficial associations ought to be systematically discouraged, and we ought to value the negative or rejecting power of the memory. The finest intellects are as remarkable for the ease with which they resist and throw off what does not concern them as for the permanence with which their own truths engrave themselves. They are like clear glass, which fluoric acid etches indelibly, but which comes out of vitriol intact. LETTER XI. TO A MASTER OF ARTS WHO SAID THAT A CERTAIN DISTINGUISHED PAINTER WAS HALF-EDUCATED. Conventional idea about the completeness of education--The estimate of a schoolmaster--No one can be fully educated--Even Leonardo da Vinci fell short of the complete expression of his faculties--The word "education" used in two different senses--The acquisition of knowledge--Who are the learned?--Quotation from Sydney Smith--What a "half-educated" painter had learned--What faculties he had developed. An intelligent lady was lamenting to me the other day that when she heard anything she did not quite agree with, it only set her thinking, and did not suggest any immediate reply. "Three hours afterwards," she added, "I arrive at the answer which ought to have been given, but then it is exactly three hours too late." Being afflicted with precisely the same pitiable infirmity, I said nothing in reply to a statement you made yesterday evening at dinner, but it occupied me in the hansom as it rolled between the monotonous lines of houses, and followed me even into my bed-room. I should like to answer it this morning, as one answers a letter. You said that our friend the painter was "half-educated." This made me try to understand what it is to be three-quarters educated, and seven-eighths educated, and finally what must be that quite perfect state of the man who is whole-educated. I fear that you must have adopted some conventional idea about completeness of education, since you believe that there is any such thing as completeness, and that education can be measured by fractions, like the divisions of a two-foot rule. Is not such an idea just a little arbitrary? It seems to be the idea of a schoolmaster, with his little list of subjects and his professional habit of estimating the progress of his boys by the good marks they are likely to obtain from their examiners. The half-educated schoolboy would be a schoolboy half-way towards his bachelor's degree--is that it?