GENETIC TYPE AND THE ENDOCRINES 611 



This dog, however, was more inactive in the conditioned 

 food taking situation, since the response was completely in- 

 hibited after a short time. In the motor experiments, how- 

 ever, 1153 S was in the excitable or B group. Thus this dog 

 is also classified as having a mixed behavioral nature. 



Bassethound-German shepherd F 1 backcrossed on basset- 

 hound. Two hybrids, produced by mating a bassethound- 

 shepherd F x to the parent bassethound, were studied in an 

 attempt to determine if dogs theoretically more bassethound 

 in inheritance would show the behavioral characteristics of 

 the pure breed. All F x hybrids have legs of intermediate 

 length and carry the factor for both long and short. When 

 the F x is bred back to the pure bassethound, all offspring- 

 should be short legged (see p. 61, Stockard). In this case, 

 however, the bassethound parent was 219 S , obtained by 

 mating bassethound 83$, referred to on page 50 (Stockard), 

 to "Dilligence." Number 83$ carried the genetic factor for 

 long legs, since her line had been crossed with the foxhound. 

 For this reason, one of the backcrosses used in the experi- 

 ments, 710 9 , was long legged while the other, 709 $ , of the 

 same litter, was short legged. Both dogs fall well within 

 the bassethound group in bodily shape, however, with indices 

 of 87 and 89 (text-fig. 108). 



In the conditioned salivary situation, both dogs were classi- 

 fied with the thin group, 709 $ with a rating of B-minus and 

 710 9 with a rating of B. However, when 709 6 was trained 

 with the motor experiments, it was found to fall into the 

 A group with the bassethound. This dog never formed a 

 satisfactory continued avoiding reaction and was not greatly 

 disturbed by shock, an unexpected performance after the 

 reactions to the salivary situation. Animal 710 9 was not 

 trained with the motor response, but it is felt that one case 

 is enough to indicate that the backcross of an F : on the 

 bassethound parent will not necessarily give a type similar 

 to the bassethound. The genetic factors determining behavior 

 are too complicated to result in the pure type of performance 

 when an F 1 is bred back to either parent type. 



