May 28, 1897.] 



SCIENCE. 



831 



tion of injurious agents, but we cannot look 

 upon it as the most perfect mode of protec- 

 tion of the body against invading micro- 

 organisms. One may inoculate into three 

 animals, even of the same species, but pos- 

 sessed of diiierent individual resistance, the 

 same quantity of the same culture of a 

 pathogenic micro-organism and obtain 

 sometimes the following results : The first 

 one will present no appreciable inflamma- 

 torj' reaction whatever and no evidences 

 of any other disturbance, and examination 

 will show that the micro-organisms have 

 quickly disappeared. The second one will 

 develop an extensive local inflammation 

 and survive, but after a long illness. The 

 third one will offer little resistance to the 

 micro-organism, which rapidly multiplies 

 without causing marked inflammation, in- 

 vades the blood or produces toxaemia, and 

 quickly destroys the life of the animal. 

 l>row, it is evident that the best protective 

 mechanism is that brought into action by 

 the first animal, but that the inflammatory 

 reaction set up in the second one is better 

 than the absence of reaction and of other 

 defenses in the third animal. 



I can scarcely do more on this occasion 

 than to indicate some of the points of view 

 from which it seems to me that we can best 

 approach the study of inflammation as an 

 adaptive process. With inflammation, as 

 with other adaptive processes, any useful 

 purpose subserved afi'ords no explanation 

 of the mechanism of the process. We 

 should guard against all ideas which in- 

 troduce, even unconsciously, the conception 

 of something in the nature of an intelligent 

 foresight on the part of the participating 

 cells. The response of these cells in in- 

 flammation is a necessary and inevitable 

 one determined by their innate properties. 

 Our efforts should be directed, in the first 

 place, toward as near an approach as pos- 

 sible to a mechanical explanation of in- 

 flammatory processes by a study, on the 



one hand, of the properties and mode of 

 action of the causes of inflammation, and, 

 on the other hand, of the nature and source 

 of the cellular properties concerned. We 

 may properly inquire whether these prop- 

 erties fit the cells to counteract the effects 

 of injurj', and if so, whence comes this fit- 

 ness. Has the fitness those attributes of 

 relative perfection which we find in most 

 physiological adaptations, or is it character- 

 ized by the uncertainties and imperfections 

 of so many pathological adaptations? Is 

 the character of the response to injury in 

 inflammation such as to indicate that the 

 agencies concerned have acquired through 

 evolutionary factors a special fitness to 

 meet the pathological emergencies? Are 

 all or only a part of the manifestations of 

 the inflammatory processes adaptive? 



It cannot be doubted that there are innate 

 properties of certain cells called into action 

 in inflammation, such as those manifested 

 in the attraction of leucocytes and other 

 cells by definite chemical substances, the 

 capacity of cell-proliferation from causes 

 connected with injury, the power of pha- 

 gocytosis and other bactericidal properties, 

 which may be adapted to counteract the 

 effects of injurious agents. When these 

 forces bring about the prompt destruction 

 or removal of the injurious substances, and 

 the defect is quickly repaired, the adapta- 

 tion is complete and unmistakable. When, 

 however, the inflammatory irritants and 

 their destructive eifects persist, and the 

 proliferation of cells and accumulatioii of 

 inflammatory products become excessive 

 and occupy large areas, the features of 

 adaptation are not so easily recognized. 

 The mere occupation of territory by in- 

 flammatory products is often a serious in- 

 jury, and it can be regarded as an adaptive 

 feature only when they fill some artificial 

 defect. Such occupation may be in itself 

 enough to counteract any useful work 

 in which these products may be engaged. 



