654 O. D. ANDERSON 



pneumatically cushioned platform upon which the animal 

 stands. Such a platform consists simply of a light wooden 

 floor over a framework resting- upon a sealed rubber tube, 

 the other end of which is connected to the tambour. 6 



Below the line representing the body movements is the 

 record of the flow of saliva from the parotid duct. Each 

 upward movement of the signal electro-magnet, which is 

 manually operated by a telegraph key, represents a unit of 

 1/100 cc. The bottom line gives the time in seconds. 



The record, considered as a whole, clearly shows the time 

 relations of the various components of the total reaction. 

 Note the oscillating head movement, the alert, tremulous 

 body movement and pose, the hastened and altered respira- 

 tory rhythm and the ready and continuous flow of saliva 

 while the metronome is beating. The saliva flows continuously 

 when the animal is eating the food and ceases within a few 

 seconds after the food has been consumed. 



Figure 2 (pi. 107) shows the posture of another animal 

 just before and during the sounding of the metronome signal- 

 ling the approach of an electric shock. Note in the left picture 

 the quiet and calm attitude of the animal before stimulation, 

 in the right picture the anticipatory flexing movement of the 

 limb as the clicking sound is heard. Below is shown the record 

 of the total defense reaction. Again, the three lower lines 

 show records of the conditioned stimulus, the unconditioned 

 stimulus (the shock) and the time in seconds. Since the de- 

 fense reaction involves movements of the head as well as 

 the limb, these have also been recorded (top line), as in 

 the salivary reflex. 



At the beginning of the conditioned stimulus the dog lowers 

 his head at once and assumes a crouching posture. The first 

 flexion movement of the leg occurs in nearly every case at 

 exactly this time. The head is soon raised and the foot again 

 lowered to the floor. These two reactions, or integrated single 

 reaction, occur repeatedly during the clicking signal. Note 

 these facts by comparing the top line for head movement 



8 Used by Benedict in basal metabolism work on dogs. 



