246 POPULAR SCIENCE MONTHLY. 



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 mislead- 

 ing 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 ques- 

 tions, so the work goes on, and the things discovered are never like what 

 was anticipated by the good and conservative people who know before- 

 hand 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 be- 

 gun 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 con- 

 nected with them, that each particular nerve cell has a specific func- 

 tion 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 



