AN ANALYSIS OF THE LEARNING PROCESS IN THE SNAIL 27 



training in the food-pressure series. In the case of Snail 4, 

 response followed the first nine trials. The last two of these 

 are separated by an interval of 48 hours from the first seven. 

 The effect of training thus persisted for 96 hours. Similar 

 results were obtained from Snails 5, 6, 7, 8 and 14. 



Immediately following the mouth response to pressure of 

 trained Snail No. 4 (Table IV) seven successive applications 

 of pressure gave no response. Similar results were obtained 

 with the other five snails. 



Snails which before training gave no response to pressure, 

 gave, following training, a response consisting of a series of 

 mouth reactions. This response is given on the first trial and 

 continues to be given in trials extending over a period of 96 

 hours. It then suddenly ceases. There is no response of the 

 mouth to subsequent stimulation of the foot by pressure. 



E. Experiments to determine the effect of training on food- 

 pressure response: second food-pressure series. — It was believed 

 that another series of tests on the same snails, reintroducing 

 the same " conditioned " stimulus, would be of interest in show- 

 ing the ease or difficulty in re-establishing the reflex. As noted 

 in Table IV, the snails were tested on two experimental days 

 after pressure alone had failed to be effective as a stimulus. 

 Allowing for the alternation of experimental days, made neces- 

 sary^ by the twenty-four hours of starving previous to experi- 

 mentation, the second series of tests using food and pressure as 

 a stimulus was started approximately 120 hours after the dis- 

 appearance of reaction upon the application of pressure as a 

 stimulus. Fiftv tests were given and the results appear in 

 Tables V and VI-D. 



