208 BIOLOGICAL PHYSICS 



as communal, effort, in personal aesthetics and hygiene, 

 which will amply repay both the individual and the com- 

 munity, in both these aspects of this most important and 

 all-pervading subject its reward being ultimately realised 

 and expressed in the ability to appreciate the word, cir- 

 cumspice. 



As we have, elsewhere, endeavoured to show that every 

 period of the life of the individual human being is charac- 

 terised by certain external, or cutaneous, appearances, it 

 will be sufficient here to recapitulate that infancy, youth, 

 middle life and age, are stamped with such indelible and 

 unmistakable features that they are evident to the "man 

 in the street," and that it is generally found unnecessary 

 to put a question to the subject of observation in order 

 to test the truth of " the first impression." 



These "tell tale" appearances usually involve the whole 

 textures of the skin, and are evolved by the incidence of 

 certain specific and constantly occurring histological 

 changes which fundamentally alter the proportions of 

 these textures in their relationship to each other, as well 

 as to the subjacent non-cutaneous tissues. The very 

 unusual expediting, or retarding, of these normal cutaneous 

 changes, should, therefore, be a warning to the clinician, 

 when called to give a pathological reason for their 

 occurrence, and should put him on his guard against 

 coming to '* rash conclusions " and unjustified suspicions, 

 notwithstanding that he may have some claim to be 

 adjudged a " Sherlock Holmes." 



We are persuaded it will be found that the great 

 determining cause of these cutaneous changes is the 

 altering relationship in arrangement and proportions of 

 the two neural elements of the skin, the sympathetic and 

 the systemic, and of the involved blood vasculature, these 

 changes occurring in regular and rhythmic manner, in 

 accordance with the conditions, and requirements, of the 

 ages, or stages, of life the sympathetic nervature pre- 

 dominating at the, earlier and later stages, and the 

 systemic at that stage when the proper work and functions 

 of life are being daily taken part in, or when the " battle 

 of life " is being daily waged. Thus, in infancy and age, 

 the predominance of the sympathetic and reflex nervine 



