Page:Popular Science Monthly Volume 67.djvu/252

246 and mind phenomena are declared to be outside the province of physical science, yet the same was said about astronomy and geology and chemistry not many generations ago. "Was not Newton condemned for dethroning the Almighty by proposing the law of gravitation for keeping the planets in their orbits? Was not war made upon those who undertook to show that the earth was more than 6,000 years old, and were not the chemists who showed how organic compounds could be formed believed to be enemies of the truth and bent on misleading mankind? Isn't it curious to contemplate that those who know least about a given science should be the ones to set its limits, who know what can not be done or hoped for so much better than those who devote their lives and their best endeavors to discover what is true and what seems probable? To-day men's lives are not endangered as they used to be for their attempts to find an answer to puzzling questions, so the work goes on, and the things discovered are never like what was anticipated by the good and conservative people who know beforehand what can and what can not be known, and it is a bit sad that the latter must die that a new generation may arise to possess the new truth. It took more than two generations to convince the world of the truth of the nebular theory, that the earth was millions of years old, that mankind had occupied the earth for hundreds of thousands of years, and the doctrine of evolution is hardly forty years old, yet are there not many who give it no credence? Perhaps one of the good things which the twentieth century will be able to accomplish will be effectually to warn everybody of the danger of setting any limits to knowledge, also that any opinion mankind has held that has not been through the crucible of science is probably wrong, but the only reason for holding this is that so far every one so tested has been found to be erroneous.

The study of nerves, their connections and activities, has been begun in earnest only within the past few years, but what has been learned seems to lead to as many surprises as has any other branch of science. Only here and there is there now an investigator in this branch, but these have already found out that all nervous action is spent upon the muscles. That all are in one way or another connected with them, that each particular nerve cell has a specific function and substitution seems no more possible among them than can the eye be substituted for hearing or for tasting. At present work is being carried on to determine the functions of various parts of the brain, especially for the effects of use and. disuse, the nature of exhaustion, the rate of recuperation, the source of energy and of automatic activity, what happens in sleep, in the hypnotic state, in disease, insanity and in unconsciousness. Dr. Hall has said that the nerves are the most wonderful things in the world, and we know so little about them. Mind and thinking, conditioned by their presence