The suggestion may here be made that whatever we do is the result (or ought to be) of a decision to do it, that follows a mental process not very different from that invented by the German General Staff for solving military problems. By this process one writes down-- 1. The mission--the thing which it is desired to accomplish. 2. The difficulties in the way of accomplishing it. 3. The facilities available for accomplishing it. 4. The decision--that is, how to employ the facilities to overcome the difficulties and accomplish the mission. In solving a military problem (or in solving many of the problems of daily life) it is often a matter of great difficulty to arrive at a clear understanding of what the mission actually is, what one really wishes to accomplish. In the majority of ordinary cases, however, the mission stands out as a clear picture in the mind. Such a case would be one in which an enemy were making a direct attack; for the mission would be simply to repel it. Another case would be one in which the mission was stated by the terms of a problem itself; for instance, to build a steam engine to develop 1000 horse power. In the case of the inventor, the mission seems to be sent to him as a mental picture; he suddenly sees a dim picture in his mind of something that he must make. Perhaps, many centuries ago, some man who had been laying out plots of ground in Egypt, of different shapes and sizes, and making computations for each one, suddenly saw a phantom picture in which all the lines and figures appeared grouped in a few classes, and arranged in conformity to a few fixed rules. The mission was given to him free, but it devolved on him to formulate the rules. As soon as he had formulated and proved the rules, the science of Geometry existed. It is interesting to note that the conception of the idea required no labor on the part of the conceiver. He was virtually a passive receiver. His labor came afterwards, when he had to do the constructive work of "giving to airy nothing a local habitation and a name." The Egyptians seem to have learned the use of many drugs, though they can hardly be said to have invented a system or a science of medicine. They did, however, invent a system of characters for indicating the weights of drugs. Those characters are used by apothecaries still. The first means of cure were incantations that evidently influenced the mind. It is interesting to note that modern systems tend to decrease the use of drugs and increase that of mental suggestion.