198 T. C. STEPHENS 



dictable, and seems as mechanical as the response of the electric 

 bell." 



He points out, however, that this reflex does not long remain 

 unmodified; that it may be inhibited by satiety, or accelerated 

 by hunger. The rapidity of the reflex is dependent chiefly upon 

 the hunger state; though it appears, in some cases, at least, 

 to be necessary that the food be placed in contact with a certain 

 region of the buccal cavity in order to provoke a prompt re- 

 sponse. In one brood of Cuckoos with which Herrick worked 

 he found it habitual for the adult to place its bill just within 

 the tip of the nestling's beak, or place the insect food across 

 between the mandibles of the young; in such instances the 

 response was slow, the parent and young often remaining thus 

 interlocked and motionless for five minutes by the watch, and 

 commonly for two minutes .On the other hand, in another 

 nest of the same species it was customary for the parents to 

 place the food deep in the throat of the young. And here, 

 says Herrick, " Every trial was a reaction test, and upon failure 

 to swallow promptly, the food was withdrawn and another 

 nestling was tested, precisely as in vireos, thrushes, and other 

 passerine birds." 



The exact conditions under which the parent awaits the reflex, 

 or repeats the stimulus upon the same nestling, or carries the 

 test to another bird, is a problem which may well be further 

 investigated. 



One of the interesting questions in connection with the feeding 

 of passerine nestlings is as to the practice of regurgitation by 

 the parents. It is quite possible that all of the passerine families 

 are not uniform in their method of feeding the young. It is 

 also quite probable that much of the difference of opinion in 

 the matter is due to lack of agreement in terminology. It is, 

 of course, important to know whether the passerine birds are 

 uniform in this particular form of behavior. 



The first necessity is the determination of the meaning of 

 the word " regurgitation." It would perhaps not aid in our 

 present purpose to attempt to analyse the different senses in 

 which the term has been used by various ornithological writers, 

 but we may at once resort to that court of appeals, the dictionary. 

 The Century Dictionary defines the word as meaning " To pour 

 or cause to rush or surge back." The Standard Dictionary 



