482 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1921. 



dition, once it has set in, is generally continuous though not always 

 regular. 



The great difference in the frequency and average grade of the 

 loss of hair between the males and females is difficult to explain. 

 Possibly the weight of the female hair acts as a tonic. The differ- 

 ences between the head covering in the males and females may also 

 have an effect. But in all probability a more or less male-linked pre- 

 disposition to the condition is already inherited. 



In this case, again, we have no similar data on other peoples that 

 could be used for comparison ; but as interest in these secondary mani- 

 festations will grow, such data will doubtless be forthcoming. 



CONCLUSIONS. 



The above data on the eyes and hair permit the formulation of 



the following conclusions regarding pigmentation in the Old Ameri- 

 cans. 



SKIN. 



1. Two-thirds of the old stock males and three-fourths of the fe- 

 males show skin that may be classed as medium. 



2. In only 5 per thousand in males, but in 52 per thousand in the 

 females, is the skin plainly lighter than the medium. All of these 

 cases are associated with pure light eyes and light or red hair. 



3. In a little over one-fourth of the males and in one-sixth of the 

 females the skin is perceptibly darker than medium. Such skin is 

 generally associated with brown eyes and medium to dark hair. 



HAIR. 



1. Only 1 among 16 males and 1 among 14.5 females has real blond 

 hair. 



2. One-half of the males and over four-tenths of the females show 

 medium dark (or "medium brown") hair. 



3. In one-fourth of the males and three-tenths of the females the 

 hair is dark (" dark brown ") to near black. 



4. In approximately 1 per cent in the males and but a little more 

 in the females the hair is fully black. 



5. In 2.6 per hundred of males and 4.9 per hundred of females the 

 hair is red or near red. 



6. The females show a slight to moderate excess of true blonds 

 (especially golden and yellow), but also of darks, blacks, and reds, 

 over the males. 



7. There are some areas in which hair pigmentation among the 

 Old Americans, due to isolation and more thorough mixtures, differs 

 from that of the group as a whole. 



