Wright: Color Inheritance in Mammals 



475 



formula EyEyAbAb there is only feeble 

 development of black and the appear- 

 ance is sooty yellow. In the presence of 

 the agouti inhibitor EyEyAA even this 

 feeble black entirely disappears and 

 the rabbit is clear yellow. On raising 

 the level of production of black by 

 replacing Ey by E, the sooty yellow 

 becomes black (EEAbAb) and the 

 clear yellow becomes gray (EEAA) , the 

 agouti factor now inhibiting black only 

 in. part. On further raising the level 

 to Ed (or ED in Punnett's nomen- 

 clature) the black can become no 

 blacker (EdEdAbAb) but the inhibitor 

 in gray rabbits is entirely neutralized 

 and formula EdEdAA gives black. 

 This factor is not entirely dominant as 

 heterozygotes may show a few agouti 

 hairs on the nape of the neck giving a 

 color which Punnett calls agouti-black. 

 Among these heterozygotes, Punnett 

 found a difference which seemed to him 

 to eliminate the hypothesis of multiple 

 allelomorphs. According to him EDEd 

 (EdE on the hypotheses of triple 

 allelomorphs) is agouti black but EDEyd 

 (or EdEy) is black. It is, indeed, 

 surprising to find the yellow factor Ey 

 determining a greater tendency toward 

 black than its allelomorph E. But the 



anomaly appears equally great to the 

 writer in both theories and so cannot be 

 used as an argument. Further, the 

 figures so far presented do not seem 

 altogether demonstrative on this point. 

 For a critical test it would be necessary 

 to obtain the two heterozygotes (EdE 

 and EdEy) from the same litter and 

 prove a difference in appearance. It 

 may be that either formula may be 

 black or agouti-black depending on 

 subsidiary factors and a comparison of 

 them when derived from different 

 crosses may lead to erroneous results. 



CHOCOLATE RABBITS 



Punnett also reported on a variation 

 which replaced black by broAvn in all 

 combinations and is apparently com- 

 parable with the brown variations of 

 other rodents. He noted an increase 

 in the amount of yellow in agouti-browns 

 (AAEdEbb) as compared with agouti- 

 blacks (AAEdEBB). This is in har- 

 mony with conditions in other cases. 

 As in pink-eyed agouti guinea-pigs, the 

 weakening of black by a factor of class 

 2b permits an extension of yellow 

 although not in so direct a way as 

 reduction of level in a factor of a class 

 2a 3 such as in the series Ed, E, Ey just 

 discussed. 



The Supposed Law of Compensation 



Ralph Waldo Emerson made famous 

 the law of compensation, according to 

 which, Nature always compensates those 

 who are in any way handicapped, and 

 vice versa. Those who have great 

 ability in abstract thinking, it is sup- 

 posed, will be inferior in ability at con- 

 crete problems; those who are slow to 

 learn will be long to remember; those 

 who are weak in arithmetic will be good 

 in history, and those who have beauty 

 will lack brains. The exact methods of 

 modern psychology have so uniformly 

 shown this so-called law to be baseless, 

 that it has long been discredited, and 

 every student knows that, in general, 

 the reverse holds true: that correlation, 

 not compensation, is the law of nature. 

 The man who is Quickest to learn will 



in most cases have the best memory; 

 the man who excels in arithmetic is likely 

 to be above the average in historical 

 erudition; and the best-looking people 

 usually have more than ordinary intelli- 

 gence. In many years of research, 

 almost no cases have been found which 

 bear out Emerson's generalization ; hence 

 it is something of a surprise to find 

 several such cases reported by W. A. 

 McCall of Teachers' College (School 

 and Society, 1917, pp. 24-30). Restates 

 emphatically, however, that the cases 

 which he reports are exceptional, and 

 do not shake the general rule that 

 superiority in one thing involves super- 

 iority in other things. "To him that 

 hath shall be given" is certainly the 

 general law of man's nature. 



