ADAPTATION AND INFLAMMATION 163 



done, its mission in life fulfilled, it withdraws its pseudopodia, 

 and dies contentedly." 



It is needless to say that we hold no such views regarding the 

 intelligence of the leucocyte. At the same time we unhesitat- 

 ingly regard inflammation as purposeful, every whit as much 

 as we regard the iris, with its contraction and dilatation under 

 different intensities of light, as subserving a purpose, or the 

 acts of feeding and digesting as being with purpose. Inflamma- 

 tion is a physiological process in so far as it is the calling into 

 action, in response to accustomed stimuli, of properties normally 

 possessed by the tissue ; it is a pathological process in so far 

 that, while the stimuli are in kind not different from normal 

 stimuli, in intensity they are greater. If we admit physiological 

 purpose, we must admit pathological. This may, indeed, be 

 laid down regarding all pathological conditions, namely, that in 

 them we are dealing not with the effects of new and unaccustomed 

 factors, but with the ordinary factors telling upon the tissues in 

 an abnormal way, being either deficient or excessive in their 

 action. Within physiological limits, the reaction to a given 

 stimulus is nicely balanced and adequate ; when the stimulus 

 is excessive, the reaction is liable to be imperfect. The iris 

 accommodates and adequately protects the retina within certain 

 limits, but if the eye be exposed to too intense a light, the iris 

 fails to arrest all the rays and the retina suffers. And so it is 

 that, in inflammation, when the stimuli are excessive and so 

 have become irritants, the tendency is for the reaction not to be 

 perfectly balanced, and the ultimate result to be an incomplete 

 counteraction of the disturbance. But, to repeat, if we recognize 

 purpose in the one set of cases, we must recognise it in 

 the other. 



All, it will be. seen, depends upon what is our conception of 

 " purpose " in vital phenomena. That conception is teleo- 

 logical if and when we regard it as primary as what may be 

 termed an intelligent endeavour on the part of the tissue to 

 accomplish a certain object, a predetermined end. To suppose 

 that, in inflammation, the vessels dilate and bring about in- 

 creased exudation in order to flush out the irritant is an utterly 

 wrong and baseless idea. If, on the other hand, our conception 

 is along these lines that in the course of evolution those in- 

 dividuals survived who, by chance, let us say, happened to 



