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SCIENCE. 



[N. S. Vol. V. No. 126. 



those who labor at the bedside, but also by 

 those who in the laboratory devote them- 

 selves to the study of the structure and 

 functions of the body in health and disease. 

 It is one of the most gratifying results of 

 the rapid advance in medical education in 

 this country during the last few years that 

 successful workers in the laboratory may 

 now expect some of those substantial re- 

 wards which formerly were to be looked for 

 almost exclusively in the fields of practical 

 medicine and surgery. We already have 

 abundant assurance that the steady im- 

 provement in opportunities and recompense 

 and other material conditions essential for 

 the prosecution of scientific work in medi- 

 cine will enable this country to contribute 

 to the progress of the medical sciences a 

 share commensurate with its great re- 

 sources and development in civilization. 



The subject of ' Adaptation in Pathologi- 

 cal Processes,' which I have selected for 

 my address on this occasion, is one which 

 possesses the broadest biological, as well as 

 medical, interests. It is this breadth of scien- 

 tific and practical interest that must justify 

 my choice of a theme which involves many 

 technical considerations and many problems 

 among the most obscure and unsettled in 

 the whole range of biology and of medicine. 



I shall employ the epithet ' adaptive ' to 

 describe morbid processes which bring about 

 some sort of adjustment to changed condi- 

 tions due to injury or disease. In view of 

 the more technical and restricted mean- 

 ing sometimes attached to the term ' adap- 

 tation ' in biology, objection may be made 

 to this broad and general application of the 

 word in pathology ; but no more suita- 

 ble and convenient epithet than ' adaptive ' 

 has occurred to me to designate the entire 

 group of pathological processes whose re- 

 sults tend to the restoration or compensa- 

 tion of damaged structure or function, or to 

 the direct destruction or neutralization of 

 injurious agents. Processes which may 



be described variously as compensatory, re- 

 generative, self-regulatory, protective, heal- 

 ing, are thus included under adaptive patho- 

 logical processes. These processes are, in 

 general, more or less advantageous or useful 

 to the individual ; but for reasons which 

 will be stated later the conception of patho- 

 logical adaptation and that of advantage to 

 the individual are not wholly coextensive. 



Within the limits of an address I cannot 

 hope to do more than direct attention to 

 some of those aspects of the subject which 

 seem to me to be of special significance. Al- 

 though most striking examples of adaptation 

 are to be sought in comparative and vege- 

 table pathology, what I shall have to say will 

 relate mostly to human pathology. My pur- 

 pose is not to point out the beauties or the ex- 

 tent of adaptations in pathological processes, 

 but rather to say something concerning the 

 general mechanism of their production and 

 the proper attitude of mind regarding them, 

 and to illustrate the general principles in- 

 volved by a few representative examples. 



It has been contended that the conception 

 of adaptation has no place in scientific in- 

 quiry ; that we are justified in asking only 

 by what means a natural phenomenon is 

 brought about, and not what is its meaning 

 or purpose : in other words, that the only 

 question open to scientific investigation is 

 How ? and never Why ? I hope to make 

 clear by what follows in what light I regard 

 this question, and in this connection I shall 

 simply quote Lotze, who, beginning as a 

 pathologist, became a great philosopher : 

 ' ' Every natural phenomenon may be inves- 

 tigated not only with reference to the 

 mathematical grounds of its possibility and 

 the causes of its occurrence, but also as re- 

 gards the meaning or idea which it repre- 

 sents in the world of phenomena." 



The most wonderful and characteristic 

 attribute of living organisms is their active 

 adaptation to external and internal con- 

 ditions in such a way as tends to the wel- 



