6 HEREDITY OF SKIN COLOR IN NEGRO-WHITE CROSSES. 



relatively great amount of pigment is formed in the corium; and this 

 excess disappears as the formation of pigment in the epidermis is 

 accelerated. 



At the Sloane Hospital in New York City seven colored babies, 

 2 to 20 days old, were examined. The youngest, of fairly dark ancestry, 

 was already becoming pigmented and his skin color gave N 15, R 41, 

 Y 2, W 42. One of the others, at 4 days, had feet that were pink and 

 quite like those of a white infant, though the forehead (the part most 

 exposed to the Hght) had about 25 per cent N. Excepting one prac- 

 tically "white" child, all had spots on the sacrum varying in size 

 from a centimeter to a third of the whole surface of the back. All 

 children had nearly straight hair, often standing erect on top of the 

 head, but a colored infant was seen whose hair at birth formed close 

 coils. 



A series of measurements can be given of the skin color of a baby 

 both of whose parents are, so far as known, of straight negro origin. 

 These were taken by the physician in charge* of the maternity division 

 of the Lincoln Hospital, New York City. The baby was born at 2 a.m., 

 February 16, 1913; first observed at 2 p.m. of the same day. At the 

 time of the first observation light brown lanugo was plentiful on the 

 back; the head hair was black and quite straight. The deepest pig- 

 mentation was on the forehead and the descending helix of the external 

 ear. There was a sacral spot, 65 by 70 mm., and a smaller, darker, 

 slightly purplish area just above the anal fold, 35 by 25 mm. and with 

 the color formula ofN58,R3i,Y4,W7. These lumbar spots faded 

 slightly in the next 10 days. The color of the forearm was determined 

 on successive days and the following formulae obtained: February 16, 

 2 p.m., N37, R38, Y7, W18; February 17, 2 p.m., N 40, R42, Y5, 

 W13; February 18, 2 p.m., N43, R42, Y3, W12; February 19, 2 p.m., 

 N 45, R 42, Y 3, W 10; February 22, 2 p.m., N 50, R 40, Y 2, W 8. 



In a colored baby, partly white, beginning 14 hours after birth 

 with a formula N 37, R 36, Y 3, W 24, by the end of 7 days the skin 

 color was N 40, R 44, Y 4, W 12. In the latter case the development 

 of pigment was much slower and would probably not go so far. 



The presence of sacral spots in mulattoes has been recorded by 

 Lehmann-Nitsche (1904) and by Herrman (1907). The latter states 

 that they were distinct in 24 per cent of the infants seen at the Vander- 

 bilt Clinic, New York City. So far as my experience went, practically 

 all negro infants showed the spots. 



In order to find what allowance, if any, must be made in our 

 statistics for age, the determinations of the percentage of the black 

 component have been grouped into classes as follows: under i year; 

 I year and up to (but not including) 2 years; 2 years and up to (but 



*Dr. Nathan B. Eddy. 



