are fairly consistent. This means probably that generations of inbreeding 

 have separated out a population which has several distinctive characters in a 

 homozygous state, that is, either pure dominant or pure recessive. 



Human Hybrids From the earliest times of which we have any record, 

 tribes everywhere seem to have had rules intended to keep the population 

 "pure". That is, peoples tried to guard against "contamination" by foreign 

 blood. Every tribe, every village, was the very center of its own universe, 

 and each cherished legends regarding its origin through a special act of the 

 gods. All strangers were likely to be enemies. In the course of time, tribes 

 have become amalgamated into larger units. Hostility toward outsiders and 

 loyalty to insiders gradually consolidated neighboring groups into larger 

 federations and nations. The many tribal myths which made each fairly dis- 

 tinct group feel itself to be God's chosen people had to be expanded to fit the 

 nation. Today, however, neither the facts of history nor the facts of biology 

 can justify us in identifying race with nation. 



Human types have apparently always crossed wherever two or more tribes 

 came close together, whether through war or commerce. In modern times, 

 with the amount of travel tremendously increasing through larger and swifter 

 cars, boats and airplanes, there has been more and more intercrossing of stocks. 

 As a result, there are more kinds of "hybrids" and also subsequent segregation 

 and distribution of distinctive physical traits. In a mixed crowd in every 

 large city you can see faces that you recognize as coming from faraway 

 regions. And you can see many individuals whom it is quite impossible to 

 assign to any particular nation or even "race". Eyes and noses and lips and 

 chins and head shapes and cheek bones have been brought together from 

 all parts of the world in new combinations (see illustration opposite). 



Many of the distinct traits that we see in human beings must result from a 

 multiplicity of factors or genes, since there is a great deal of "blending". We 

 may observe almost perfectly continuous gradings in the various characters, 

 such as stature, coloring of skin, hair and eye, proportions of the head, 

 and shapes of the various features. Today we must search in out-of-the-way 

 places for examples of "pure" strains, and explorations by airplane will no 

 doubt continue to reveal isolated groups of human beings — like the 

 village of "white Indians" found in Central America before the Second 

 World War. 



As in other species, hybridizing among human beings shows no effects that 

 are uniformly advantageous or disadvantageous. In many cases, indeed, the 

 offspring of mixed marriages do "combine the best features of both" parental 

 stocks. Those who have feared the possible ill effects of racial mixture seem 

 to have been influenced by group pride or feelings of superiority rather than 

 by any actual knowledge of the outcome of crossing. All kinds of crossings 

 seem to produce harmonious combinations. 



518 



