190 ^Journal of Coynparative Neurology arid Psychology. 



Dr. G. Eyerich and Dr. L. Loewenfeld and are published in a 

 memoir by these authors, bearing the title: "Uber die Beziehun- 

 gen des Kopfumfangs zur Korperlange und zur Geistigen Ent- 

 wicklung."^ The statistics which are given in most complete 

 form in the memoir provide data for 935 Bavarian soldiers in the 

 ordinary two-year service, regarding intelligence and head circum- 

 ference. The data are recorded in two tables; the first of these 

 gives as one variable the head circumference of the individuals 

 in 0.25 millimeter classes, and as the other variable the 

 "intellektueller Begabung," the individuals being sorted into four 

 classes designated as follows: "I, sehr gut beanlagt"; "Ila, gut 

 beanlagt"; "lib, normal"; "III, beschrankt." The second 

 table gives the same data with classes Ila, and lib, of the intelli- 

 gence scale combined into one, the rubrics then being "sehr gut," 

 "gut," and "schwach." As the only data of a similar kind which 

 have hitherto been analyzed biometrically are those of Pearson 

 on Cambridge undergraduates^ and English school children^ it 

 seemed to me desirable to reduce these German data in order that 

 comparisons might be instituted. 



The all-important matter in dealing with data of this character 

 is to know something- about the basis of the classification on the 

 intelligence side. If there is any constant bias in the distribution 

 of the individuals into whatever "intelligence" classes are adopted 

 it is clear that the resulting: statistics will lose all significance so 

 far as our problem is concerned. In order that as clear an idea 

 as possible may be gained of the nature of this German material 

 in this respect it seems best to quote in full what the authors say in 

 regard to the matter. On page 26 of the memoir referred to is the 

 following statement : 



Um die Verwertung des gesammelten Materials zu vereinfachen, haben wir 

 die untersuchten Personen beziiglich ihrer geistigen Befahigung in 3 Klassen 

 gesondert: insolche von mittlerer, 1. e., durchschnittlicher Begabung und in solche, 

 deren Begabung iiber und unter dem Durchschnitt steht. Die uns vorliegenden 

 Angaben iiber die geistige Oualifikation der untersuchten Leute ermoglichten 

 jedoch die Trennung der Durchschnittsgruppe in 2 Untergruppen und lassen 

 auch eine solche wiinschenswert erscheinen : eine Gruppe, die den iiber dem Durch- 



' Wiesbaden, J. F. Bergmann, 1905, pp. 55. 



'Pearson, K. On the Correlation of Intellectual Ability with the Size and Shape of the Head. 

 Proc. Roy. Soc, Vol. 69, pp. 333-342. 



^Lee, a., Lewenz, M. a., and Pearson, K. On the Correlation of the Mental and Physical 

 Characters in Man. Part II. Proc. Roy. Soc, Vol. 71, pp. 106-114. 



