458 hiving in a World of Change 



educated portions of western populations, by the end of the 

 Eighteenth Century. That it still persists among masses, even 

 among many men and women with diplomas, only shows 

 how difficult it is to eradicate traditional beliefs and assump- 

 tions. Both in personal or individual health and in public 

 health the last generation has seen a radical change in meth- 

 ods and principles as a result of the diffusion of the evolu- 

 tionary point of view, and especially as a result of the in- 

 tensive study of details of adaptation in man and in other 

 organisms. 



It was a great step forward when Rudolf Virchow 

 enunciated the principle that disease is " normal " — that is, 

 the inevitable manifestations of the organism under unusual 

 conditions. We have seen that Virchow, who established the 

 scientific study of pathology in terms of the normal opera- 

 tions of the body, was opposed to Darwinism as well as to 

 the general theory of evolution. His leadership resulted, 

 however, in a very rapid development of newer methods of 

 studying and interpreting the reactions of the human body, 

 with far-reaching results. Again we have the irony of a 

 man's spiritual outreach far exceeding his grasp: Virchow 

 laid the foundations on which his intellectual opponents 

 reared a noble superstructure. 



Adaptation and Human Affairs 



Formerly we could in good conscience rely upon our 

 ** instincts " to guide us in eating, or upon traditional teach- 

 ings derived from authorities or revelations. Today we must 

 be guided by experimental study, which has revealed more 

 and more of the mechanism of nutrition and of the many 

 subsidiary processes, such as digestion, diffusion, and elimi- 

 nation of refuse. If man was created directly, as in the older 

 conception, we could hope to find hardly more than the 

 " natural " conditions of living — that is, those which he 

 was presumably " intended " to follow. We could easily 

 enough blame all of our troubles upon our having departed 



