No. 502] 



NOTES AND LITER ATI' BE 



to act, 10 or into classes which are known to have lived in different 

 environments, or comparing contrasted children within the same 

 family, with contrasts in the ancestry of these (alternate in- 

 heritance) or other schemes which seek to find measurable in- 

 fluence of the environment factor, are, some or all, necessary for 

 any final proof. 



What the correlation coefficients do show is this, that if hered- 

 ity be the great preponderating force, creating individual dif- 

 ferences between man and man, the coefficients that have been 

 found are in substantial agreement with what they should be. 



Further refinement is wanted, especially as to the effect of 

 assortative mating, and the shape of the curve of distribution 

 for psychic characters, when selected classes are taken. 



Mendel's laws, so important to the horticulturists, and to the 

 breeder of superficial traits in fancy strains of domesticated 

 animals, has not been shown to have any bearing on human 

 heredity, at least as concerns important characteristics. 11 The 

 general rough principle of alternate inheritance in human hered- 

 ity, leads, however, to the hope that a further study of this ques- 

 tion may bring out certain "unit characters," more or less 

 marked, so that here in the end there may be harmony between 

 the two unfriendly schools, the Mendelian and the Biometrical. 



F. A. Woods. 



ORNITHOLOGY 



Riddle on the Cause of the Production of ■ 'Down" and other Down- 

 like Structures in the Plumages of Birds. 1 — A connection is here 

 traced between the rate of growth and the character of the 



10 This method is employed by E. L. Thorndike in his excellent study of 

 the " Measurement of Twins." Arch, of Philos., Psychol, and Scientific 

 Methods, No. 1, New York, 1905. Also in some of the University College, 

 London memoirs. 



11 It has been claimed to govern the inheritance of certain rare 

 anomalies, albinism, abnormal hands, etc., also eye color (C. B. and G. C. 

 Davenport, Science, Vol. XXVI, p. 589) and facial peculiarities of Bed 

 Indians when crossed with the Scotch (G. P. Mudge, Nature, November 7, 

 1907). 



Middle, Oscar. The Cause of the Production of "Down" and other 

 Down-like Structures in the Plumages of Birds. Biological Bulletin, Vol. 

 XIV., No. 3, February, 1908, pp. 163-176. 



