This study is based on the following premises: human beings differ in their physiological reactions to their different environments and consequently differ in appearance; individuals who resemble each other in observable characteristics tend to be grouped together geographically; therefore, races exist in man as in any other species.

This study is based on the following premises: human beings differ in their physiological reactions to their different environments and consequently differ in appearance; individuals who resemble each other in observable characteristics tend to be grouped together geographically; therefore, races exist in man as in any other species.