THE INHERITANCE OF FAMILY TRAITS 121 



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Fig. 88. — Ideal scheme, showing method of inheritance of color blindness. 

 Typically it appears in sons only of simplex females, represented by a heavy 

 ring. The third mating in second generation is illustrated in Fig. 89, II, 6. 



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Fig. 89. — A remarkable and exceptional pedigree of color blindness. The 

 fraternity, II, 1-5 (which comprises the grandfather, his brothers, and his 

 3 sisters), were said all to be color blind. The grandmother, II, 6, had the 

 normal color sense but had an afifected brother. The entire fraternity, III, 1-5, 

 including 4 females, has impaired color perception. Details are given about 

 III, 5, as follows: She is about 50 years old, a physician's wife, and a test 

 shows complete confusion of dark green, dark red and brown. While lighter 

 tints are better distinguished, rose and blue arc confounded. The sons show 

 exactly the same conditions. Reber, 1895. 



ters may inherit color blindness from fathers. At least such 

 is the history given by Reber (1895), Fig. 89; an exceptional 

 history that is not entirely without precedent. In the case 

 of these exceptional families a color blind parent may have 

 color blind offspring of either sex. 

 o. Myopia. — That the shape of the eyeball is largely 



