matter anew if the conditions change. We demand material, but relative truth. One of the acutest thinkers, J. R. von Mayer, the discoverer of the working principle of “conservation of energy,” says, “the most important, if not the only rule for real natural science is this: Always to believe that it is our task to know the phenomena before we seek explanation of higher causes. If a fact is once known in all its aspects, it is thereby explained and the duty of science fulfilled.” The author did not have us dry-souled lawyers in mind when he made this assertion, but we who modestly seek to subordinate our discipline to that of the correct one of natural science, must take this doctrine absolutely to heart. Every crime we study is a fact, and once we know it in all its aspects and have accounted for every little detail, we have explained it and have done our duty. But the word explain does not lead us very far. It is mainly a matter of reducing the mass of the inexplicable to a minimum and the whole to its simplest terms. If only we succeed in this reduction! In most cases we substitute for one well-known term, not another still better one, but a strange one which may mean different things to different people. So again, we explain one event by means of another more difficult one. It is unfortunate that we lawyers are more than all others inclined to make unnecessary explanations, because our criminal law has accustomed us to silly definitions which rarely bring us closer to the issue and which supply us only with a lot of words difficult to understand instead of easily comprehensible ones. Hence we reach explanations both impossible and hard to make, explanations which we ourselves are often unwilling to believe. And again we try to explain and to define events which otherwise would have been understood by everybody and which become doubtful and uncertain because of the attempt. The matter becomes especially difficult when we feel ourselves unsure, or when we have discovered or expect contradiction. Then we try to convince ourselves that we know something, although at the beginning we were clearly enough aware that we knew nothing. We must not forget that our knowledge can attain only to ideas of things. It consists alone in the perception of the relation and agreement, or in the incompatibility and contradiction of some of our ideas. Our task lies exactly in the explication of these impressions, and the more thoroughly that is done the greater and more certain is the result. But we must never trust our own impressions merely. “When the theologian, who deals with the supersensible, has said all that, from his point of view, he can say, when the jurist, who represents those fundamental laws which are the result of social experience, has considered all reasons from his own point of view, the final authority in certain cases must be the physician who is engaged in studying the life of the body.”