September 15, 1916] 



SCIENCE 



365 



Miiller, Helmholtz, Du Bois-Reymond and 

 Briicke and by Ludwig. 



Helmholtz, recognizing the limitations 

 set by the existing chemical and physical 

 knowledge, devoted himself only to those 

 branches of science which seemed capable 

 of exact chemical and physical explana- 

 tion; Du Bois-Reymond contented himself 

 with the study of the narrow field of elec- 

 trical phenomena of living organisms, and 

 did more than any one else to show that 

 physiological problems are capable of being 

 handled with the same precision as the 

 purely physical; Ludwig, with character- 

 istic fearlessness and enthusiasm, attacked 

 problem after problem, striving to find out 

 how many of the subtle processes of life 

 were susceptible of a mechanical explana- 

 tion. 



Ludwig 's "Lehrbuch der Physiologie des 

 Menschen, ' ' the first edition of which came 

 out from 1852-1856, and the second, from 

 1858-1861, was dedicated to his friends, 

 Briicke, in Vienna, Du Bois-Reymond, in 

 Berlin, and Helmholtz, in Bonn. The 

 writer's point of view was diametrically 

 opposed to that of his predecessors. 

 Throughout the book the explanation for 

 vital processes is sought in pure mechan- 

 ics, in the widest sense. He wrote in the 

 introduction : 



The problem of scientific physiology is to de- 

 termine the functions of the animal body and de- 

 duce them as a necessity from its elementary con- 

 ditions. 



Whenever the body of an animal is subdivided 

 to its ultimate parts, one always finally arrives at 

 a limited number of chemical atoms, and upon 

 phenomena which are explainable on the assump- 

 tion of a light ether and electricity. One draws 

 the conclusion in harmony with this observation, 

 that all forms of activity arising in the animal 

 body must be a result of the simple attractions 

 and repulsions which would be observed on the 

 coming together of those elementary objects. 

 This conclusion would be unassailable, if it were 

 possible to show with mathematical accuracy, that 

 the elementary conditions were so arranged in 



the animal body with respect to direction, time 

 and quantity, that all of the phenomena of living 

 and dead organisms must necessarily flow from 

 their interaction. 



This conception, as is well known, is not the 

 traditional; it is the one among the newer, which, 

 as especially opposed to the vitalistic, has been 

 named the physical. The view, aside from all de- 

 tails, finds its justification in the irrefutable de- 

 mand of logic, that a cause shall underlie every 

 result, and further in the soundest rule of every 

 experimental science, that one draws only on ab- 

 solutely necessary grounds of explanation. 



Du Bois-Reymond toward the end of the 

 year 1848 said: 



The belief in a vital force, like the other 

 dogmas, depends less on scientific conviction than 

 the need of a soul to certain organizations; that is 

 why this belief, like that of the dogmas, can not 

 be rooted out. 



The slowness with which the new view 

 was accepted is demonstrated by the fact 

 stated by Kronecker, that Claude Bernard, 

 only towards the end of his life, 1876, made 

 the definite statement: 



Que les conditions de manifestations de la vie 

 sont purement physieo-chemique et ne different par 

 sous ce rapport des conditions de tous les autres 

 phenomenes de la nature. 



In 1895 Mosso wrote from Italy : 



After a short truce during which vitalism ap- 

 peared to be abandoned, we see it born again 

 under another form. Literature and art bear wit- 

 ness to the reaction which produces itself, and on 

 all sides one detects the breath of mysticism which 

 invades the mind. The school of the neo-vitalists 

 has already conquered the pulpit, and many fear 

 that it will stifle the spirit of true science, as 'it 

 has done in the Catholic universities. 



Tigerstedt, one of Ludwig 's favorite pu- 

 pils, who has become one of the best known 

 of the physiologists of our time, and who, 

 although a Finn, was unanimously chosen 

 as president of the International Congress 

 of Physiologists, which was to have met in 

 Paris this autumn, gives perhaps the best 

 expression of the attitude of the present- 

 day physiologists: 



