42 LULU F. ALLABACH. 



the stimulus, that causes the fatigue. This is perhaps what 

 should be expected when the nature of the food reactions is 

 taken into consideration. In taking food the region in contact 

 with the food produces a very large quantity of mucus, envelop- 

 ing the food body. It is not surprising that successive imme- 

 diate repetitions of this excessive production of mucus gradually 

 exhausts the region. As is usual in fatigue, strong stimuli may 

 produce reaction for some time after weak ones have failed. 



The fatigue thus caused usually lasts only two to five minutes. 

 After this period has elapsed the fatigued region is frequently as 

 ready to take food as before - - provided the animal is still hungry. 



Nagel and Parker have held that the result of their experi- 

 ments " illustrates the extreme looseness, or even independence, 

 of the nervous activities of the two sides of the animal " (Par- 

 ker, 1896, p. 1 1 6) --since the effects of the experience of one 

 side are not transmitted to the other side. With the recognition 

 that these results are a simple matter of fatigue, they perhaps 

 cease to have any bearing on the question of the closeness or 

 looseness of nervous interconnection. In the highest organisms, 

 as man, fatigue induced by repeated contractions of a finger of 

 the left hand, in erogographic experiments, is not transmitted ap- 

 preciably to the right hand. But the experience gained by touch- 

 ing a hot iron with the left hand would nevertheless later prevent 

 the right hand from touching it. 



II. OTHER MODIFICATIONS IN BEHAVIOR. 



A very peculiar modification of behavior is seen in the follow- 

 ing : A specimen refuses to take filter paper, though it still takes 

 meat. After it has thus refused paper, two or three pieces of 

 meat are given in succession, and taken readily. Now the bit of 

 paper is again placed on the disk, and it too is swallowed. 

 Clearly, the uninterrupted taking of a number of pieces of meat 

 changes the physiological condition of the animal in some way, 

 preparing it for the taking of any object with which it comes in 

 contact. (After a larger number of pieces of meat, the paper is 

 refused, as we have before seen.) 



Acclimatization to weak stimuli is readily demonstrated in 

 fresh, active specimens of Metridium. If a light stream of water 



