76 



Milton Landowne 



from the study. It is therefore plausible to consider that 

 certain of the agewise changes in the "normal" response are 

 due to disease; and, as a result, the test indulges an increasing 

 tolerance in the clinical evaluation of older subjects. A similar 

 picture exists for the general as well as the cardiac arterial 

 circulation. Fig. 2 represents data for arteriosclerosis of the 

 aorta from the Mayo Clinic experience (Willius, Smith and 

 Sprague, 1933). While general morbidity statistics do not 



N » 3236 



non e 



slight -» 



moderate 



marked- 

 extreme' 



100% 



80 - 



-60 - 



40 - 



20 



322 



1300 1004 



all ages 



Fig. 2. Gross morphological total and agewise incidence of aortic 

 sclerosis, graded as to severity. Source and legend as in Fig. 1. 



reveal arterial disease in the extremities to be extremely 

 common, this refers to clinical and not to latent disease; and 

 clinical manifestations are commonly complications or 

 sequelae. The incidence of sub-clinical disease might tell the 

 same story as do the figures for aortic involvement. 



Parenthetically, the arterial disease referred to is mainly 

 atherosclerosis. In concept, this may exist as a process or 

 tendency well in advance of even subtle morphological, 

 physical or chemical indices. Thus, even when we shall have 

 the diagnostic techniques to detect arterioscleroses before 



