THE CAUSATION OF DISEASE. 307 



then it may be pointed out that, even supposing no abnormal 

 inter-action is taking place in the atheromatous patch, this 

 latter may lead to abnormal inter-action elsewhere, by inter- 

 fering, for instance, with proper vasomotor action, and thus it 

 still will constitute disease as above defined ; but if it be further 

 urged that not only need there be no abnormal inter-action 

 between cell and cell-E in the atheromatous patch, but that no 

 secondary trouble need follow in other parts, then I reply that 

 such an atheromatous patch cannot constitute actual disease ; 

 and, if this be true, it follows that there may he distinct ah- 

 normality of structure without actual disease. All will acknow- 

 ledge that this is true of mere anatomical curiosities, such as 

 horse- shoe kidneys and supernumerary digits ; but if our defini- 

 tion of disease is accepted it is also true of other structural 

 abnormalities which do not fall under the category of mere 

 curiosities, such, for instance, as cases of dried-up abscesses 

 and fatty tumours, which interfere in no way with the func- 

 tional efficiency of the tissues. There is ample scope here for 

 scholastic discussion, but there is no occasion to pursue the 

 subject further. 



2. Diseases in which there is no Discoverable Abnormality of 

 Structure. — Such diseases are frequently styled u functional " 

 diseases. A functional disease may therefore be defined as 

 one in which no lesion is discoverable as a cause. 



We shall have presently to inquire whether, in such func- 

 tional disorders, there is necessarily structural change ; mean- 

 while, there is something to be said about this term functioned 

 as applied to disease. It is clearly a bad term, since altera- 

 tion in function is not peculiar to disease unaccompanied 

 by obvious structural change ; it very rarely happens that any 

 gross structural change is unattended by disordered function. 

 In some few cases, such as those cited above, of dried-up abscess, 

 fatty tumour, and such like, there may be no functional abnor- 

 mality, but this is very exceptional, for even if no symptoms 

 are forthcoming — no evidence of the disorder during life, 

 whether in the shape of altered function or otherwise — this 

 does not show that there is actually no alteration of function. 

 I hold that in almost all cases of gross structural change 

 there actually is a modification of function ; but whether this 



