818 



SCIENCE. 



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



some situations ! If we look upou inflam- 

 mation as an attempt to repair injury, and, 

 therefore, as an adaptive process, with what 

 imperfections and excesses and disorders and 

 failures is it often associated ! How often in 

 some complex pathological process, such as 

 Bright's disease or cirrhosis of the liver, can 

 we detect some adaptive features,attempts at 

 repair or compensation, but these overshad- 

 owed by disorganizing and harmful changes! 



It is often difficult to disentangle in the 

 complicated processes of disease those ele- 

 ments which we may appropriately regard 

 as adaptive from those which are wholly 

 disorderly and injurious. There are usually 

 two sides to the shield, and one observer 

 from his point of view may see only the 

 side of disorder, and another from a differ- 

 ent point of view only that of adaptation. 



The conception of adaptation in a patho- 

 logical process is not wholly covered by 

 that of benefit to the individual. I under- 

 stand, as has already been said, by an 

 adaptive pathological process one which in 

 its results brings about some sort of adjust- 

 ment to changed conditions, due to injury 

 or disease. This adjustment is usually, 

 wholly or in part, advantageous to the in- 

 dividual ; but it is not necessarily so, and 

 it may be harmful. The closure of patho- 

 logical defects by new growths of tissue is 

 a process which must be regarded as adap- 

 tive. But one would hardly describe as 

 advantageous the scar in the brain which 

 causes epilepsy. A new growth of bone to 

 fill in defects is often highly beneficial ; but 

 what grave conseq^^ences may result from 

 thickening of the skull to help fill the space 

 left by partial arrest in development of the 

 brain in embryonic life or infancy ! We 

 see here, as everywhere, that " ISTature is 

 neither kind nor cruel, but simply obedient 

 to law, and, therefore, consistent." 



In turning now to the more special, but 

 necessarily fragmentary, consideration of a 

 few of the pathological processes in which 



adaptation, in the sense defined, is more or 

 less apparent, I shall have in view the 

 answers to those two questions. What is 

 the meaning of the process ? and How is it 

 caused ? which confront us in our investiga- 

 tion of all natural phenomena. At the out- 

 set it must be admitted that our insight 

 into the nature of many of these processes 

 is very imperfect, and that here answers tO' 

 the world-old riddles Why ? and How ? are 

 correspondingly incomplete and liable to err. 



Although almost all of the elementary 

 morbid processes, even the degenerations 

 and death of cells, may, under certain con- 

 ditions of the body, serve a useful purpose^ 

 the preeminent examples of pathological 

 adaptation, in the sense of restoration or 

 compensation of damaged structure or func- 

 tion, or the direct destruction or neutraliza- 

 tion of injurious agents, are to be found 

 among the compensatory hypertrophies^ 

 the regenerations and the protective proc- 

 esses. To this last ill-defined group I refer 

 parasiticidal and antitoxic phenomena, and 

 some of the manifestations of inflammation, 

 and perhaps also of fever. In the last 

 analysis these protective processes, no less 

 than the others mentioned, must depend 

 upon the activities of cells. 



As it is manifestly impossible within the 

 limits of a general address to attempt a de- 

 tailed consideration of any large number of 

 these adaptive pathological processes, and 

 as such consideration would necessarily in- 

 volve the discussion of many technical and 

 doubtful points, I have thought that my 

 purpose would be best served by the selec- 

 tion of a few representative examples. 



The compensatory hj^pertrophies afford 

 admirable illustrations of certain fundamen- 

 tal principles regarding adaptations in 

 pathology which I have alread}' stated. 

 The hypertrophy secures a functional ad- 

 justment, often of a highly beneficial charac- 

 ter, to certain morbid conditions. This use- 

 ful purpose is attained by a succession of 



