No. 5:Ui] 



COLOR INHERITANCE 



465 



with great variations in size (the larger "granules" may 

 be the result of fusion of smaller masses). 



Statement of Kesvets and Reeated Facts 

 The facts whose interpretation is sought in terms of 

 some principle of heredity are these: (1) The degree of 

 skin coloration is due to the variable number of pigment 

 granules in the cells of the rete mucosum Malpiglii involv- 

 ing incidentally a variable number of more superficial 

 cells. (2) The pigment granules (melanic) of all skin 

 (albinos excepted) are identical in size (practically), 

 shape and color (without qualification). (3) The ascend- 

 ing scale of morphological conditions paralleling a pro- 

 gressively deepening grade of pigmentation may be 

 described as follows: (a) few cells of basal layer pig- 

 mented with few granules— blonds, (b) more cells contain- 

 ing more granules— brunets, (c) a more or less complete 

 basal layer of cells with many and very many melanic 

 granules (mulattos), (d) the cells of basal layer packed 

 and distended with pigment granules ; the cells of the more 

 superficial layer also with veiy many granules. 



Or, restated and explained, (4) The progressive in- 

 crease in progressively darker skins both in the number 

 of granules and in the number of the pigmented cells. 

 That these two facts are related to each other as cause 

 (number of granules) and effect (number of pigment 

 cells) is strongly indicated by the fact that in light mulatto 

 and brunet skins, where only the basal cells are distinctly 

 pigmented, the number of granules per cell in general de- 

 creases with the progressively lighter shades. 



(5) The results recently published by the Davenports 

 showing a segregation of the original skin colors (grand- 

 parental colors) among the individuals of the third gen- 

 eration, i. e., children of mulatto parents. 



(6) The accumulation of the pigmented cells near the 

 border line between the dermis and epidermis or in the 

 vicinity of the blood stream. 



(7) Melanin formation is an intracellular metabolic 

 process going on independently and in a measure propor- 

 tionately in both dermis and epidermis. This seems 

 demonstrated by the researches of Meirowsky and others, 



