PHYSICAL SCIENCES TO SCIENCE IN GENERAL. 233 



the natural sciences labor indirectly toward the same goal, by endeavor- 

 lug to free man more and more from external necessities. Every single 

 investigator performs his part and chooses such tasks as are most suited 

 to his mental endowments and culture. But every one must remem- 

 ber, also, that he is able to further the great work only in conjunction 

 with the rest, and that it is therefore his duty to make the results of 

 his labors as clear and as accessible to them as possible. Then he will 

 find assistance in others and they in him. The annals of science are 

 rich in proofs of such mutual relations between sciences apparently the 

 most remote. Historical chronology is based upon astronomical calcu- 

 lations of eclipses of the sun and moon, recorded in ancient histories. 

 Conversely, many important data in astronomy, such as the time of 

 revolution of many comets, are based upon old historic records. Lat- 

 terly, Briicke and other physiologists have found it possible to build up 

 a system of all articulate sounds of wuich the human organs of speech 

 are capable, and to base upon it suggestions for a universal alphabet 

 adapted to all human languages. Here, then, physiology has entered 

 the service of the science of language, and has furnished the explana- 

 tion of many curious changes of sound, which are determined not by 

 the law of euphony, as had been before supposed, but by a. similarity 

 in the positions of the organs of si)eech. The science of language, in 

 return, throws light u])()n the ancient relationship, separation, and 

 migrations of tribes in prehistoric times and on the degree of civilization 

 to whieh they had attained before their separation; for the names of 

 those objects which they could name then, are found to be common in 

 later languages. Thus the study of language furnishes us with the 

 history of times of which we have no historical documents. Let me 

 furthermore remind you of the assistance which anatomy can afford 

 the sculptor and the arch?eologist who examines ancient statues. If I 

 may be permitted to refer to some of my own latest works, I will men- 

 tion that it is possible to demonstrate the elements of our musical sys- 

 tem by the physics of sound and the physiology of its sensation, a 

 jn^oblem belonging entirelj^ to iiesthetics. The physiology of the organs 

 of sense is most intimately connected with psychology, because it 

 proves results of ijsychological processes in the perceptions of sense 

 which do not come within the scope of conscious reflection, and must, 

 therefore, remain concealed from psychological self-observation. 



I could only mention here the most striking examples of the mutual 

 relations of sciences and those which required the fewest words, and 

 was, therefore, obliged to choose those existing between the most 

 remote branches. But the influence which each science exercises over 

 the one nearest akin to it is, of course, much greater. It is self-evident; 

 it requires no illustration; you all know it from your own experience. 



I therefore consider every individual as a laborer at a common great 

 work, touching the noblest interests of the whole human race ; not as 

 one striving to satisfy his desire of knowledge, or his own advantage, 



