ON THE TRUE AIM OF PHYSIOLOGY. 821 



ON THE TRUE AIM OF PHYSIOLOGY.* 



By Professor W. PEEYEE, 



OF THE UNIVERSITY OF JENA. 



FOR a long while I have felt the desire to answer in a popular 

 treatise the question, What ways and aims ought physiology to 

 pursue ? Most naturalists consider the explanation of all phenomena, 

 including those of living bodies, only satisfactory if mechanical — that 

 is to say, if, in strict logical sequence, it is based upon the principles 

 of modern physics as taught by Galileo nearly three centuries ago. 

 Thus, G. Kirchhoff considers the highest aim which the natural sci- 

 ences have to strive for to be the discovery of the " forces " existing 

 in Nature and of the condition of "matter" ; in other words, "the 

 explanation of all natural phenomena by means of mechanical laws." 

 The fact that besides the forces, which mechanics has to deal with, 

 there exist, too, chemical forces independent of the former, is illus- 

 trated by an hypothesis : " The same particles of matter, which at a 

 greater distance affect each other only through gravitation, manifest, 

 when placed in proper proximity, molecular forces, which appear in 

 their protean forms, now as forces of elasticity, of cohesion and adhe- 

 sion, now as forces of chemical affinity." The proof to what extent 

 chemical affinity is a molecular force dependent on the unequal prox- 

 imity of bodies affecting each other chemically, is wanting. It also 

 remains an open question whether at greater distances masses act upon 

 each other only through gravitation. But, lest it should be inferred 

 that inorganic nature only must be explained mechanically, Professor 

 Kirchhoff, in accord with many naturalists, adds : " We must confess 

 that at present we possess but little knowledge of the condition of 

 matter as well as of the forces through which its particles act upon 

 each other, and that our comprehension of natural phenomena, even 

 of those connected with inorganic bodies, is as yet very imperfect. 

 The same may be said with respect to the much more complex pro- 

 cesses which take place in plants and in animate bodies. In either 

 case a true conception can not be formed so long as the mechanical 

 theory has not been satisfactorily demonstrated. This goal never will 

 be reached by the natural sciences, but the mere fact of its having 

 been recognized as such gives a certain satisfaction, and in approach- 

 ing it we experience that highest enjoyment which the investigation 

 of the phenomena of Nature affords." 



I am unable to share that satisfaction, since I do not recognize such 

 a goal as the true one, nor does the approach to it afford that high 

 enjoyment, because of our progress being constantly impeded by facts. 

 The processes in a living body, even in mere protoplasm, can not pos- 



* Translated for " The Popular Science Monthly " from the " Deutsche Eundschau." 



