VARIATION AM HKHKD1TY 



15 



color (red) doe* not completely dominate the other. In 

 OM6 tii.- in. i niinants how a color (pink) which 



is a I-!- 10 colors of th* al generation. 



: .l.- in.nl.- ..r inheritance has been dem- 



at.-d to hol.l for a great lr..-rsity of organisms: 

 in r .its, rabbits, guinea pigs, rattle, poultry, 



canaries, snails, silk-moths ; in beans, maize, wheat, bar- 

 ley, and stocks. In a* pie, hornlessness is 

 the dominant an. I presence of horns the recessive char- 



. In wheat, rough and red -ha: iie dominant 



and smooth and white chaff the recessive characters. 11 

 It i> dirtirult to <lraw definite conclusions from the study 

 ot human inheritance on account of the great com pi 

 of the human organ Man is tin- result of tin- inter 



ire of so many <1 t stocks that there are no 



"pun lines." Since experiment is out of the question, 

 observation must be n-Ii.-.l upon. But the rate of in 

 crease of the human species is slow (about 60 generation- 

 of men since the Chri>tian era began), and th- number of 

 offspring are few. In spite of these difficulties -t 

 have been made with tin- n-ult that certain human trait- 

 appear to lu> inherited in accordance with Mend 

 -. lf For example, 18 



Curly hair, dominant. 

 Dark h 



Brown ryrs. 



Normal pigmentation, 



roly<lartyly. 



Normal nervous system. 



u'lit hair, 



t to red hair. 

 Mine eyes, 

 Alhinism, 

 Normal, 

 Normal. 



Hereditary feeble-mindediMM, 

 insanity, epilepsy, 



n Thomson & Ctoddc*, op r.r . ,. 138. 



it BOM. V.Tke JfiW of Primitto* Jfn. 1011. ; 



w Davenport, C. B. Heredity in Relation of fff*fct, pp. 31. 66, 77 



