6l2 IVm. E. Kellicott 



toads was not determinable with sufficient accuracy to afford 

 evidence. 



In conclusion, it seems that the general subject of correlation 

 is one of increasing importance. Attention has been so largely 

 given to the subject of variation that the facts of correlation, which 

 may prove to be the more significant, have not received their due 

 share of attention. 



The "balance of fitness" which is the result of growth or selec- 

 tion is not a condition merely to be guessed at or estimated; it is 

 measurable by a series of correlation coefficients among a consider- 

 able number of characters. The "summum bonum" is a condi- 

 tion of high correlation, be the associated variability higher or 

 lower. To be fit an organism must exhibit throughout its organ- 

 ization a certain degree of proportion of its parts. This condition 

 of fitness is measurable by a series of correlation coefficients not 

 only of external dimensions and skeletal characters but also of 

 size and strength of muscles, the position of their insertions upon 

 the skeletal elements, the size (though only an approximate indi- 

 cation of efficiency) of viscera and especially of nerve centers, and, 

 were the technique possible, also of the efficiency of sense organs 

 and of the accuracy and intensity of reactions. And lastly, looking 

 in this direction, studies in correlation should include not only the 

 relation of pairs of organs in a large number of individuals but 

 farther of the relation between a large number of representative 

 characters among single individuals. The collection of data upon 

 this last topic is now in progress. 



The Woman's College 



of Baltimore, Md. 



June, 1007 



V LITERATURE CITED 



BuMPUS, H. C, '97 — A Contribution to the Study of Variation. Skeletal Varia- 

 tions of Necturus maculatus, Raf. Jour. Morph., xii, 455, 1897. 



CuENOT, L., '99 — Sur la determination du sexe chez les animaux. Bull. Sci. de 

 la France et Belgique, xxxii, 462, 1899. Original paper not acces- 

 sible — abstract by the author in L'Annee Biologique, xv, 212, 1901. 



Davenport, C. B., '04 — Statistical Methods. 2d ed., New York, 1904. 



