GENETIC TYPE AND THE ENDOCIUXES 635 



legs of the shepherd reappear in the second generation in 

 the Mendelian ratio of one short to three long. Head and 

 body shape also vary among the F^s. There is in no ease 

 a complete dominance of either the bassethound or shepherd 

 bodily form. 



Two striking observations were made regarding the be- 

 havior of these dogs. First, some dogs were as inactive as 

 the bassethound grandparent and others as active as the 

 German shepherd grandparent. Second, there was more varia- 

 tion in the behavior of the individual dogs in different situa- 

 tions. One dog of the group was round in bodily type and 

 behaved like the bassethound in all experimental conditions ; 

 two were thin and very active. The others ranged between 

 these extremes for both bodily type and behavior character- 

 istics. 



These observations on the F, and F 2 bassethound-German 

 shepherd hybrids give some basis for an understanding and 

 interpretation of quantitative variations among different con- 

 stitutions. The bassethound and German shepherd may be 

 considered pure constitutional types. Constitution, as used 

 here, refers to the total organismal complex, including bones, 

 glands, and nervous system, and in these two types a definite 

 harmonious genetic complex determines these factors (see 

 sections on inheritance of bones, glands, etc.). This purity 

 refers also to behavior patterns and determiners, and in 

 addition may be observed in regard to special aptitude. It 

 is well known, for example, that the bassethound is easily 

 trained for hunting. This ability is dependent not only on 

 a highly sensitive olfactory center, but on the general nervous 

 nature of the dog as well. An animal such as the bassethound 

 is not easily diverted from the trail by accessory stimulation, 

 as would be the case with an excitable dog. The general 

 nervous nature and the special aptitude combine to form the 

 basis of the hunting reaction. The two breeds, the basset- 

 hound and German shepherd, are each homozygous, not only 

 for physical form, but, as shown in Section V, for glandular 



