estimation of very common temperatures must be accepted as correct. E.g., anybody accustomed to have his room in winter 14 degrees R. will immediately notice, and correctly estimate, the rise or fall of one degree. Again, anybody who takes cold baths in summer will observe a change of one degree in temperature. It will, therefore, be possible to believe the pronouncements of witnesses concerning a narrow range of temperatures, but all the conditions of perception must be noted for the differences are extreme. It has been shown, e.g., that the whole hand finds water of 29 degrees R. warmer than water of 32 degrees R. which is merely tested with the finger. Further, Weber points out,[186] “If we put two adjacent fingers into two different warm fluids the sensations flow together in such a way that it is difficult to distinguish differences. But if we use two hands in this test, it is especially successful when we change the hands from one fluid to another. The closer the points on the skin which receive contemporary impressions, and perhaps, the closer the portions of the brain to which these impressions are sent, the more easily these sensations flow together; while again, the further they are from one another the less frequently does this occur.” In the practice of criminal law such matters will rarely arise, but estimations of temperature are frequently required and their reliability must be established. It is important to know what a wounded man and his enemy feel in the first instant of the crime and in what degree their testimonies are reliable. First of all, we have to thank the excellent observations of Weber, for the knowledge that we find it very difficult to discover with closed eyes the angle made by a dagger thrust against the body. It is equally difficult to determine the direction from which a push or blow has come. On the other hand we can tell very accurately in what direction a handful of hair is pulled. With regard to the time it takes to feel contact and pain, it is asserted that a short powerful blow on a corn is felt immediately, but the pain of it one to two seconds later. It may be that corns have an especial constitution, but otherwise the time assigned before feeling pain is far too long. Helmholtz made 1850 measurements which proved that the nervous current moves 90 feet a second. If, then, you prick your finger, you feel it a thirtieth of a second later. The easiest experiments which may be made in that regard are insufficient to establish anything definite. We can only say that the perception of a peripheral pain occurs an observable period after the shock, i.e., about a third of a second later than its cause.