GENETIC TYPE AND THE ENDOCRINES 633 



were, as a rule, hybrid dogs. In this section the dogs were 

 compared to determine the relationship between physical 

 form, glands, and behavior among pure breed types and 

 hybrids obtained by crossing these pure types. 



Two pure physical types with opposite behavior classifica- 

 tions were determined — the lethargic and the active. The 

 bassethound is found to be lethargic or inactive in all be- 

 havioral situations, and the Saluki and German shepherd 

 fall into the active group. These types also differ widely in 

 physical form. The bassethound is short legged, achondro- 

 plasic, has a round thorax and abdomen, and tends to become 

 fat. The German shepherd and Saluki are lean and "stream- 

 lined" in appearance; they have long, thin legs, with thin 

 thorax and abdominal regions, giving them a sagittal ap- 

 pearance. 



It lias been shown in Section V that the glands of the 

 bassethound differ from those of the German shepherd, while 

 the glands of the Saluki and shepherd are similar. The 

 bassethound has a low active thyroid gland, giving the animal 

 a low metabolism. This, in conjunction with the correspond- 

 ingly low active nature of the other glands, is probably one 

 factor responsible for the inexcitable nature of all the nervous 

 processes. The German shepherd and Saluki have highly 

 active thyroid glands, and this, and its influence on other 

 active glands, undoubtedly contributes to their excitable na- 

 ture. Within each breed there is a harmonious relationship 

 between the genetic factors for physical form and the struc- 

 ture of the glands, and each breeds true for this relationship. 

 These pure bred dogs also have characteristic behaviors. 

 Thus the behavior factor has been integrated into a har- 

 monious pattern with the glandular and physical factors. 

 For this reason each breed is considered pure for both 

 physical type and behavior, and since they fall into one of 

 two opposite classifications behaviorally, they are considered 

 normal extreme behavior types. 



It has already been shown in Section V that there is great 

 variation in form and glands among the F 2 bassethound- 



