22 BIOLOGY AND SOCIAL PROBLEMS 



ones continue to accumulate throughout life 

 till the obliterations of old age and death. In 

 many respects this accumulation is most di- 

 verse, for from the best remembered circum- 

 stance to the fact that is just about to be for- 

 gotten there is every gradation, and apparently 

 no circumstance remains long in the same 

 state of vividness, but all is drifting toward 

 oblivion, some portions more rapidly than 

 others, while the new is ever replacing the 

 old. 



In practical life we come to regard our re- 

 membrances as having a certain degree of com- 

 pleteness, but in reality they are the merest 

 shred of our past. Think of a vivid experience 

 in the last ten years or so and recount to your- 

 self the occurrences of the day on which it 

 happened. Very little but the most shadowy 

 outline is left. Even yesterday, so near at 

 hand, is mostly gone, and as a test for the pres- 

 ent who among us here can give again from 

 memory the first sentence of this lecture? 

 We all heard it and I read it, but even I can- 

 not repeat it. Yet if memory were in this re- 

 spect only as perfect as a dictagraph, this sen- 

 tence could be recovered from every one in 

 the room. I am fully aware that in certain 



