202 THE DISCOVERY OF THE CHILD Such errors are controlled by the material, which does not allow the mistake to be continued without being found out; they can be corrected only through the growth of the child's powers, through that modification, which will follow as a consequence of long and correct manipulation of the material. Such errors may be placed in the category described when we say that we learn by making mistakes; they are overcome by determination, with the aid of the means which are offered from the outside. The second mistake can be traced to naughtiness, or to care- less teaching as for instance, in dragging about the whole stand of solid insets like a wheelbarrow, or in building houses with the tablets of coloured silks, or in walking on the rods when laid out in a row, or in wrapping one of the cloths used for fastenings round the head like a scarf, and so on. Abusive use of material which corresponds to disorder or to needs different from those which the material can satisfy, means making no use of it; it results in waste of energy, uproar; all the actions which prevent the child from concentrating and therefore from improving and developing. It is as if a hemorrhage of the body shed that blood which ought to concentrate in the heart in order to maintain health and life. It cannot be said of the above-mentioned errors that * one learns by making mistakes'; the longer the mistake is kept going, the farther off is the possibility of learning. It is in conditions such as these that the authority of the teacher succours the erring little soul, extending to him, now gentle, now energetic help, Respect for useful Activity. If, instead of using the material wrongly, the child uses it either in accordance with the instructions of the mistress or in some other way invented by himself which shows intelligent modifications, then the teacher will leave the child to go on repeating the same exercise or making his own attempts and experiments. She will let the child have as much time as he wants without ever interrupting his activity, neither for the purpose of correcting small errors, nor by stopping the work through fear of tiring out the child.