PART III. 



CHAPTER I.* 



The Distinction between a "Natural " and an " Artificial Environment." 



We have seen that an adaptation, both personal and racial, is 

 continually taking place to the E obtaining in civilized com- 

 munities, and that this adaptation consists in a structural 

 change. We have further seen that man obtains an ever 

 stronger and more complete control over his E as evolution 

 advances, for it becomes more and more the result of complex 

 mental operations. Already this control has reached a high 

 pitch, and civilized man has surrounded himself by an E which 

 differs widely from the comparatively simple E of a primitive 

 community. The former is usually spoken of as an " arti- 

 ficial " E, the latter as a " natural " one ; and it is necessary 

 for us to ask ourselves if there is any fundamental difference 

 between the two, for it is very certain that, as time advances, 

 the E will tend to become more and more artificial, and the 

 question arises : What effect will this have upon the health 

 of the race ? 



In our study of this point we had best direct our atten- 

 tion to one or two very highly artificial forms of E, and the 

 conclusions which we shall arrive at concerning them will be, 

 a fortiori, applicable to less artificial E's. 



Practical surgery constitutes a highly artificial order of E. 

 A patient suffers, let us say, from ovarian cyst, strangulated 

 hernia, or stone, from any one of which diseases he must 



* In some of the following chapters the reader will find here and there a 

 repetition of what has gone before. This is notably the case with the chapters 

 on " Normality of S and E," and on the " Origin of Cancer." I shall be par- 

 doned, I trust, for these repetitions, since they tend to emphasize points which 

 seem to me important. 



