16 E. J. LUND 



pression in the resvilts of the experiment as the length of time 

 of feeding is increased. The final total number of grains eaten 

 when the time is long is then a more accurate index of the rela- 

 tion of the physiological state to the feeding process than if the 

 time of feeding is short. The greater this difference in the total 

 quantity of food eaten the greater is the difference in the physio- 

 logical state of the different individuals. We, therefore, have 

 in the amount of food eaten, if the length of time of feeding 

 is long enough, a fairly good relative measure of the physiological 

 state of the single individual and the differences in the physio- 

 logical state between different individuals as regards their rela- 

 tion to food at that particular time. 



2. Changes in the physiological state as shown by using the feeding 



process as an index 



If change in the dynamic conditions of the cell, as regards the 

 food relation, does occur, this should be observable by a change 

 in the feeding process, and such is indeed the fact. This is 

 shown in table 3. Material from cultures C and D was starved 

 in tap water for twenty-four hours. Five active individuals 

 were then picked out from each and tested individually. They 

 were fed twenty minutes and each one was observed continuously 

 during the experiment. The number of grains eaten and re- 

 jected and the time as called off by the observer were noted. ^ 

 In this way the time record of the relation of acceptance and 

 rejection of food was obtained. The yolk concentration, tem- 

 perature, and so forth were the same in all the tests. 



As the table shows, yolk grains were at first rapidly eaten. 

 At the end of the first few one-half minute intervals the action 

 of the cilia was frequently reversed, thus rejecting the food after 

 it had been taken into the oral apparatus. There w^as, therefore, 

 a definite change from eating to the rejection of food by the 

 feeding mechanism. This change was more rapid in general, 

 in the individuals from culture C than in those from culture D. 



* I am indebted to Mr. K. S. Lashley for kindly aiding mo in taking the records 

 of this experiment. 



