426 JOHN LINCK ULRICH 



the production of the neck reflex is not a free and easy one. The 

 latch is still sent out of the notch with considerable vigor. Evi- 

 dently the ease with which the neck reflex is produced is asso- 

 ciated with an early facilitation of directive integration. 



It is impossible to detect any variation in the performance of 

 the neck reflex movement, but, variations in the movements 

 which may be regarded as coordinated with it, or which are 

 auxiliary to it, are easily detected. When imperfect responses 

 appear after the facilitation of directive integration, these re- 

 sponses can readily be observed. These responses indicate not 

 so often an ineffective performance of the neck reflex movement, 

 but of the movements coordinated with it. In fact all imper- 

 fect responses result from imperfect coordination of these 

 integrated movements with that of the integrated neck reflex 

 movement. It is advisable, that the degree of facilitation of this 

 coordination of movements in different rats be shown. To this 

 end, an apparatus was constructed, so that accurate reaction 

 time for the neck reflex movement, and that for directive inte- 

 gration could be obtained. For, if there exists any variation in 

 the reaction time of either of these movements, there will be 

 revealed the degree of facilitation of coordination of them. 

 Moreover it might indicate at times a want of interaction of inte- 

 grated movements and other reflex mechanistic parts of the rat. 



To record the reaction time of all movements of the neck reflex 

 and of directive integration, a specially constructed latch was 

 attached to the problem box, and a platform with electric con- 

 tacts was placed in the entrance box of the hood which covered 

 the problem box. The platform was supported by two light 

 springs. Two electric contacts, one at each end on the under 

 surface of the platform were in circuit with a signal magnet and 

 batteries. Slight pressure on the upper surface of the platform 

 would bring the electric contact points together closing the cir- 

 cuit. The circuit was closed when a rat was on the platform 

 before progression inside the hood took place, and was opened 

 when progression from the platform occurred. Both these time 

 intervals were recorded by a signal magnet on a kymograph. 

 The last interval alone was used to reckon the time for the 



