INVOLUTION 483 



individual, and the variant combinations of evolutionary 

 influences to which the individual, as distinguished from 

 the community, may be subjected. Ageing is thus con- 

 fined "all things being equal" to a finely graduated 

 range of incidence in every tissue, organ, and texture of the 

 individual body, and is consistently impressed as to rate, 

 extent, and conspicuousness on the tout ensemble of that 

 body as well, so that a regular rhythmic progress, so to 

 speak, is the result a result so regularly recurrent and 

 " plain to behold," as that " he who runneth may read," so 

 that thereby mankind is saved the trouble and embarrass- 

 ment of putting direct questions, which have sometimes 

 both a negative and positive bearing at the time, which it is 

 usually politic to avoid, and which, moreover, is not 

 usually required for scientific purposes. 



Ageing impresses itself on the whole anatomical elements 

 of the body, simultaneously making itself felt in and on 

 these elements, in accordance with the character of their 

 structure and their altering conditions as to exercise and 

 nutrition, as the race of life continues to be run, and as 

 the effects of " tear and wear " on them become more and 

 more felt with the passage of time, the natural clinging to 

 the body of disengaged material, and the physical cohering 

 of disintegrated or metabolised material, to the functionally 

 living and active structures. 



Ageing thus viewed covers a very large field of ana- 

 tomical and physiological physics and dynamics, a field so 

 large, indeed, that we here can only touch the fringe of it ; 

 that fringe, however, embodies some account of the intrinsic 

 changes presented by the skin and subcutaneous textures, 

 or those personal characteristics more especially " visible 

 to the naked eye," and, therefore, easy of access to every- 

 day clinical experience and physiological observation. 



The skin and subcutaneous structures are continually 

 undergoing changes, many of which are so unapparent and 

 gradual as not to attract attention, and many so instant 

 and acute as immediately to arrest attention, and become 

 the theme of interested thought and dialogue between 

 subject and bystander, and, it may be, to afford a thesis for 

 physiological consideration and elaboration on the part of 

 some who, by special training, have had their scientific 



