Human heredity involves both physical and psychical characters--both the body and the mind are concerned. Among other animals little if anything is known regarding psychic inheritance, but the physical traits of men are inherited in just the same ways and to the same degrees as in animals. This degree or intensity of inheritance may be expressed in coefficients of heredity between the groups of relatives being compared. To mention a few examples of coefficients for physical traits we have the following: CHARACTER OBSERVED PARENTAL FRATERNAL COEFFICIENT COEFFICIENT Stature .49-.51 } .51-.55 } Span .45 } .55 } Fore Arm .42 } .47 .49 } .53 Eye Color .55 } .52 } Hair Color .57 - Average Hair Curliness .52 Head Measurements-three .55 - " Cephalic Index (Ratio between breadth and length of cranium) .49 We might give many others, but it is unnecessary. Notice that these parental and fraternal coefficients group about an average value of about .50 or slightly less. Similar coefficients have been worked out for other degrees of relationship; thus grandparental coefficients are about .25. Stated briefly, in less exact terms, these coefficients mean that, with respect to such traits as deviate from the group average, the resemblance of brothers and sisters to each other or of children to their parents is, on the whole, approximately mid-way between being complete in its deviation from the average and in not deviating at all from the average in the direction of the fraternal or parental characteristic. Grandchildren tend to deviate from the group average only about one fourth as far as their grandparents. It should be remembered that these are statistical and not individual statements, and that as many "exceptions" will be found in the direction of greater resemblance as in that of lesser resemblance.