INHERITED VARIATIONS AND FITNESS PROBLEMS 471 



healthy and sick groups, representing the young (six to fifteen years) and 

 the old (sixty years and over), the fitness value of the types of discernible 

 structural and functional characters which remain permanent after type 

 differentiation, fixation or maturity, can be determined. It has been pos- 

 sible to show a definite relation of the inheritance of scapular types to long- 

 evity and to morbidity by the application of the age-incidence principle to 

 statistical studies of healthy and sick groups. The results of such studies, 

 some of which are shown in tables 1 and 2, point unerringly to the existence 

 of 2 groups in any people : Group A — The bearers of the convex types, among 

 whom will be found a larger number of the more adaptable, the more disease 

 resistant, the plus-potentially healthy, the longer lived; Group B — The bearers 

 of the scaphoid types, among whom will be found a larger number of the less 

 adaptable, the less disease resistant, the plus-potentially sick, the shorter lived. 

 Consideration of table 2 shows that in similar age periods there are ap- 

 proximately from 1 j to 2\ times as many convex types in healthy as in sick 

 groups. 



THE RELATION OF SCAPULAR TYPES TO INHERITED CAPACITIES FOR EDUCATION 



Problems of inherited capacities for health, disease and duration of life 

 are inseparable from those of inherited capacities for education. Do scapu- 

 lar types show relation to the varying capacities for education? The 

 percentage increase of convex types in well-adaptable groups and in compa- 

 rable numbers and in similar age periods over feeble-minded groups, as indi- 

 cated in table 2, led to the investigation of the possible relation of scapular 

 types to the varying capacities for education, as measured by grades in 

 American schools and universities. These investigations have been in 

 progress on White and Negro stocks for the past three years. The results 

 derived from these stocks are similar, but a larger number of persons in 

 White stocks have been examined; hence only the results from White stocks 

 are shown in table 3. 



The singular finding of the age incidence of scapular types and the results 

 of all investigations leading to its explanation on the relation of heredity to 

 longevity; the percentage increase of convex types in healthy over sick 

 groups, and the percentage increase of convex types in higher over lower 

 school grades, have disclosed definite relations of scapular types to problems 

 of fitness for health, disease, education, duration of life and adaptation in 

 general. 



THE USEFULNESS OF SCAPULAR TYPES 



The usefulness of scapular types in fitness problems is based upon the 

 following findings: (1) that scapular types are inherited variations common 



