478 



ANNUAL REPORT SMITHSONIAN INSTITUTION, 1921. 



and Great Britain are so similar that the two people might well be 

 assumed, on general considerations, to show a parallel line of changes 

 in a physiological characteristic such as pigmentation. 



The whole subject in both countries needs a thorough scientific 

 restudy on a large scale. It would be a fallacy to believe that obser- 

 vations, however superficial they might be, if only made on a large 

 enough number of subjects, would ever show true conditions; such 

 data can at best only approximate, but may also more or less mask, if 

 not pervert, the real facts. 



GRAY HAIR. 



In 250 of the examined men and 200 women, special attention was 

 given to the subject of the graying of hair. 



The ordinary notions as to grayness are very empirical and super- 

 ficial, yet there is much of interest to be learned in this connection. 

 The condition, however, is not easy to study. Few elderly people 

 remember correctly when they began to notice gray hairs or how the 

 process progressed ; and even for the scientific observer it is not easy 

 to estimate correctly the many grades of the change. 



The best way to proceed in the study of graying was soon seen to 

 be the statistical, and the only effective way of recording was found 

 to be by estimates in percentages of the quantity of the gray hair in 

 relation to all the hair on the head. Accordingly the incidence of 

 gray hair was recorded as: None; very few to few; some to one- 

 third; approximately one-half (two-fifths to four-sevenths); two- 

 thirds to nearly all; and all. The observations gave the following 

 results : 



Old Americans: Orayness. 



Some to 



about ono- 



fchiM. 



(33) 

 13.2 per cent. 



25-57 years . . 



(29) 

 14. 5 per cent 



30-58 years.. 



Approxi- 

 mately 

 one-half. 



(11) 



4.4 per cent.. 



37-58 years . . 



(9) 



4. 5 per cent.. 



37-59 years.. 



T*vo-thirds 

 to near all. 



(41) 



16.4 per cent, 



39-65 years.. 

 (21) 



10.5 per cent, 



39-60 years.. 



All gray 

 (more or less 

 completely). 



(11) 



4.4 percent. 



48-65 years. 

 (7) 



3.5 per cent. 



51-60 years. 



These data only show that grayness long before old age in both 

 sexes is frequent; that there evidently is throughout adult life a 

 slightly less tendency to it among females than among males; that 

 for some perhaps not strictly physiological reason there is an undue 

 frequency of the two-thirds to all grays in both sexes, and that both 



