2 JQURNAL OF THE [January, 



improvement that has taken place in educational methods, has 

 come an increased appreciation of the unconvertible products of 

 learning, — those intellectual residua which no one expects to turn 

 into bread and butter. The world is finding out that truth, like 

 virtue, is its own reward. But, since knowledge is spreading with 

 tremendous rapidity, and no man can hope to cultivate the whole 

 length and breadth of even one department, he who would be 

 truly learned must dig deep at a single point. It is an old say- 

 ing, I believe : " Not he who knows many things, but he who 

 knows much, is the wise man." 



Now, I fully appreciate the fact that a knowledge of the habits, 

 structure, and systematic position of the diatoms is not a necessary 

 part of any man's intellectual equipment. Even scientific special- 

 ists, whose field of work includes this class of objects, manage to 

 get along very well with hardly more than superficial information 

 as to their appearances and characteristics, while men who pursue 

 the study of these minute wonders with more than ordinary per- 

 sistency and enthusiasm have come to be known by the half-con- 

 temptuous title, diatomaniacs. I am not particularly anxious to 

 inoculate new victims with their mania, but I shall be glad if, 

 under cover of a presentation of a few of the questions which 

 engage their attention, I am able to promote interest in the gen- 

 eral subject of microscopical research. I believe it will be found 

 that a study of this one family of very lowly beings will bring be- 

 fore us most of the leading problems of biology, and perhaps 

 some of those of physics, besides ; and I shall be disappointed 

 if, around the nucleus which my subject supplies, I fail to gather 

 a body of fact and speculation the contemplation of which will 

 prove botfi entertaining and stimulating. 



I think there is no material attribute of which science justly 

 takes as little account as it does of mere size. All immeasurable 

 things seem great, whether they are immeasurably large or im- 

 measurably small ; and in the same way all inscrutable pheno- 

 mena are awe-inspiring and overpowering. Whether we look 

 upwards and outwards, through the telescope, at the numberless 

 revolving orbs of the universe, or downwards and inwards, through 

 the microscope, at the myriad active plastides of an organized 

 creature, the same or similar questions ultimately present them- 

 selves for solution, without regard to the prodigious size and 



