The Nature Library 
to the students of biology, but the unprofessional students want 
but little of all this. I know a young woman who took a post- 
graduate course in biology at a noted summer school, and the 
one thing she learned was that certain bacilli were found only 
_in the aqueous humor of the eyes of white mice. The world 
is full of curious facts like that, that have no human interest 
or educational value whatever. 
If one could number all the trees of the forest and all the 
leaves upon the trees, what would it profit him? To know 
the different kinds of trees when you see them, and the func- 
tion of the leaves upon them—that were more worth while. 
I have read studies of leaves that were just as profitless as to 
know their numbers. I! have heard discourses upon the changes 
in the plumage of certain water-fowl from youth to age, and 
from one moult to another, that were as profitless and weari- 
some as studying the variations of the leaves or their numbers. 
I hardly know why I am impatient when people come to 
me with their hands full of different leaves and ask me what 
tree is this from, and this, and this? If your business is not 
with trees, if you live in the city and care mainly for city things, 
why bother about the trees, unless for the pleasure of it during 
your summer excursions into the country; and if it affords you 
pleasure, you will not want any one to tell you: you will want 
to identify the trees themselves. 
The same with the birds. The main profit of this branch of 
natural history is in the pursuit—not in the name, but in the bird. 
It is the chase that allures the sportsman, and it is the chase that 
profits the nature-student. Did you ever receive a gift of brook- 
trout by express? How pitiful they look—stale fish only! But 
the trout you brought in at night after threading for miles the 
mountain stream: its voice all day in your ears; its sparkle all day 
in your eyes; the love of its beauty and purity all day in your 
heart; wading through bee-balm or jewel-weed; skirting wild 
pastures; starting the grouse or the woodcock with their young; 
surprising bird and beast at their home occupations—these were 
trout with a flavor. 
Whatever opens up new doors or windows for us into the 
world about us, whatever widens the field of our interests and 
sympathies, has some sort of value—moral, intellectual, or 
esthetic. But much of the so-called nature-study opens no new 
