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 $ was in the excitable or B group. Thus this dog 

 is also classified as having a mixed behavioral nature. 



Bassethound-German shepherd F^ 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 t hybrids have legs of intermediate 

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

 the F! 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 $ , obtained by 

 mating bassethound 83 2 , 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 2 with a rating of B. However, when 709 $ 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 $ was not 

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

 is enough to indicate that the backcross of an F x 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! is bred back to either parent type. 



