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made that wonderfal progress whicli was an astonisliment to 
all who devoted themselves in these days to the study of any 
branch of natural science. It was only in that spirit that 
they could approach with any advantage those studies, and it 
was only by approaching them in that spirit that they 
could hope to derive any good from them, either for them- 
selves or for others. A poet had told us that " a little 
knowledge is a dangerous thing.'' Of course there was a 
sense in which that saying announced a great and indis- 
putable truth. A little knowledge was a dangerous thing 
if it puflPed up those who possessed it, and made them fancy 
that their knowledge was extensive and great. A little 
knowledge was a dangerous thing if it were used to show our 
superiority to those who were somewhat more ignorant than 
themselves. But he did not believe that a little knowledge 
was a dangerous thing if they knew accurately the limits 
of that knowledge, and if they ever kept before them 
the extent of their own ignorance. After all, surely it 
was true that the knowledge of the wisest among us was 
in reality small indeed. Great as had been the advance 
which had been made during the last century in the know- 
ledge of the outward world, there still remained vast 
• regions into which our knowledge had not yet penetrated, or 
had only just begun to enter ; and the difference between 
what we did know and what we did not know was infinitely 
greater than that which existed between the knowledge of 
the mere student and of him who had devoted his life 
to learning in these various branches of knowledge. He 
said, then, that a little knowledge was not a dangerous 
thing, provided they knew well what was the extent of their 
knowledge, and provided that they appreciated at its real 
value that which they did know. And surely it was encou- 
raging for all, and particularly for the young students of 
science — if there were any present — to know that, provided 
