730 O. D. ANDERSON 



administration of adrenalin. Further, in the neurotic sheep 

 the amount of nervousness increased to an enormous extent 

 on the third day. Thus the present work on the dog cor- 

 roborates the phenomena observed previously on a widely 

 different mammal, the sheep. 



The present results are briefly as follows. Injections of 

 adrenalin were given to three dogs previously trained for 

 conditioned reflexes. The motor reflex was used on two, and 

 in the third the salivary reflex. In the first dog, to which 

 a massive dose of adrenalin was given, the motor C-R showed 

 an initial increase followed by a marked decrease. The ef- 

 ficiency of the response in the second dog to which adrenalin 

 was administered on 3 successive days increased and then 

 decreased on each day, the increase followed by the decrease 

 being less on each succeeding day; finally the conditioned 

 reactions were almost entirely obliterated. The efficiency 

 was slightly decreased. In the third dog, adrenalin was 

 given continuously in three isolated periods from 3 to 5 days 

 in length. The dosage was increased in each period. In the 

 first and second periods, in which mild and medium doses 

 respectively were given (1:50,000 and 1:25,000), the salivary 

 C-R showed an initial increase followed by a decrease, which 

 was maximal on the third day. In the third period, in which 

 a very strong dose was given (1:1000), the C-R was enor- 

 mously decreased. The efficiency of the C-R in this dog was 

 somewhat increased. 



In general the increases and the decreases in the C-R values, 

 together with the appearance of general restlessness, are 

 interpreted as alterations in the level of general excitability. 



Dog 1398 $ , bassethound X Saluki F 2 . The positive motor 

 C-R alone was used, the stimulus being Met. 120. 



This dog was an exception among those used in the study 

 in that he was, under normal circumstances and from the 

 very beginning, extremely active and excitable. He was also 

 not very cooperative in the C-R laboratory, which made it 

 difficult to record and register the motor reactions. 



