GENETIC TYPE AND THE EXDOCRINES 



641 



each of these indicate the degrees of excitability under each 

 experimental condition, ranging- from the inactive animals 

 of A and A' to the active animals of B and B'. This line is 

 represented as a gradual rise because it is highly probable 

 that if enough dogs were trained the differences in excitability 

 would include many gradations between the two polar groups. 

 The pure types fall at each end of the line under both ex- 

 perimental situations. Other animals fall near A in the food 

 taking situation and near B' in the motor situation and vice 

 versa. These are the animals with the mixed constitutional 

 nature. There are possibilities for many forms of mixed 

 types, dependent on the gradation between AB and A'B'. 



PURE 



HYPCK-EKlTABLe 

 EUCUSHBULL 



Text-figure IK 



The cases represented on such a graph include only those 

 animals which were trainable under any one experimental 

 condition, that is, those dogs able to make an adequate 

 adjustment. 



It has been shown that within the specific reaction systems 

 studied in the experiments there are differences in quality 

 and degree of activity. It may be assumed that in the two 

 pure behavioral types the genetics of each system is different, 

 and the interaction between the genetic factors and the 

 glandular processes also differs. Within the pure behavioral 

 types there is a harmonious relationship between behavioral 

 systems and the other bodily organs. This holds both for 

 the inactive and the active types. Among the hybrids, how- 



