498 



The Journal of Heredity 



they die in one year they will not be 

 aHvc to die in some succeedinj^ year. 



These researches involved some very 

 difficult mathematical problems, to 

 which nothing more than an allusion 

 can be made here. Thc\' were based 

 on a statistical method known as partial 

 correlations. The object of the present 

 note is to call attention to a new stud}' 

 of the subject of natural selection, based 

 on a new statistical method, which 

 Pearson says is the most important 

 contribution to the apparatus of statis- 

 tical research that has been made for a 

 number of years past. It is termed the 

 Variate Difference Correlation method. 



Its exact nature is of interest only to 

 mathematicians, but every genctist will 

 be int'jrested in the fact that it j^ives, 

 according to Pearson, a more accurate 

 result in the study of natural selection 

 than any method heretofore known. 



RESl'LTS OF NEW STUDY 



Applying it to the registered births in 

 England and Wales between 1850 and 

 1912, and the births during the first 

 five years of life in the same period, 

 Miss Eldcrton and Professor Pearson 

 have found that the previous observa- 

 tions of a selective death rate arc con- 

 firmed with increased accuracy. "For 

 both sexes a heavy death rate in one 

 year of life means a markedly lower 



' Further Evidence of Natural Selection in Man. Bv Ethel M. Elderton and Karl Pearson. 

 Biometrika, Vol. X, Part IV, ]n>. 4SS-.S()5. London, M"ay, I'MS. 



death rat? in the same group in the 

 following year of life." This lessened 

 death rate extends in a lessened degree 

 to the year following that, but is not 

 by the ])rescnt method easy to trace 

 further. 



" It is difficult," as they conclude, "to 

 believe that this important fact can 

 be due to any other source than the 

 influence of natural selection, i.e., 

 a heavy mortality leaves behind it a 

 stronger population." 



To avoid misunderstandings, it may 

 be well to close this review with the 

 closing words of the Elderton-Pearson 

 paper. "Nature is not concerned with 

 the moral or the immoral, which are 

 standards of human conduct, and the 

 duty of the naturalist is to point out 

 what goes on in Nature. There can 

 now be scarcely a doubt that even in 

 highly organized himian communities 

 the death rate is selective, and physical 

 fitness is the criterion for survival. 

 To assert the existence of this selection 

 and measure its intensity must be 

 distinguished from an advocacy of high 

 infant mort:ility as a factor of racial 

 cf^ciency. This reminder is the more 

 needful as there are not wanting those 

 who assert that demonstrating the 

 existence of natural selection in man 

 is identical with decrying all efforts to 

 reduce the infantile death rate." 



Seeks to Find Best Nut-Bearing Trees 



Endeavoring to enlist members <;f the American Genetic Association in a search 

 for the undeveloped nut-producing resources of the United States, Professor 

 J. Rus.sell Smith, of ihc University of Pennsylvania, writes: "We now know how to 

 graft them, so that the finding of them amounts to something. We have most 

 surprising resources in the sha])e of rare nut trees, if we just knew where they 

 were. As an exani])le of these unknown resources, I will cite the recent discovery 

 in Indiana of three or four of the finest i)ecan trees in the world. It took looking to 

 find these trees from among the thousands of wild ones, but it is true that some- 

 body, some boy, some hunter, .some observant farmer, has his eye on nearly all of 

 the extra fine nut trees in his neighborhood. He .should tell the world about them, 

 that's all. The way is easy — simply send samples cf the nuts, with an account of 

 the tree, to the .secretary of the Northern Nut Growers' As.sociation, Dr. W. C. 

 Deming, Gcorgetcnvn, Conn. This Association wants your help so badl\- that il is 

 olTrring mone\- for it — S.SO for a hazel tree of American origin that can compete 

 with the imi)orte(l filberts; vSlO for a Northern i)ecan better than we now have, and 

 $20 for other nuts th'it are fo.iiid by judges to be sufficiently valuable" 



