by that of algebra,
the knowledge of geography by that of astronomy, the knowledge of one
language by knowing another. As no one thing in nature exists
unconnected with other things, so no one item in the vast sum of human
knowledge is isolated, and no person is likely to be perfectly
acquainted with any one subject who confines his attention with
microscopic minuteness to that subject. To understand thoroughly one
subject, you must study it not only in itself, but in its relations. To
know one thing well you must know very many other things.

Let us return then to the point from which we set out, namely: that one
important difference between the teacher and other operatives arises
from the difference in the objects on which they operate. The one
operates upon matter, the other upon mind. The one attains perfection in
his art by a process which in the other would produce an ignoramus, a
bungler, a narrow-minded, conceited charlatan. Hence the necessity on
the part of those who would excel in the profession of teachers, of
endeavoring continually to enlarge the bounds of their knowledge. Hence
the error of those who think that to teach anything well it is necessary
to know only that one thing. That young woman who undertakes to teach a
primary school, or even an infant class, has mistaken her calling if she
supposes that because she has to teach only the alphabet or the "table
card," she has therefore no need to know many other things. There are
some things which every teacher needs. Every teacher needs a cultivated
taste, a disciplined intellect, and that enlargement of views which
results only from enlarged knowledge.

We all know how much we are ourselves benefited by associating
habitually with persons of superior abilities. So it is in a still
higher degree with children. There is something contagious in the fire
of intellect. The human mind, as well as the human heart, has a
wonderful power of assimilation. Every judicious parent will say: Let
not my child be consigned to the care of an ill-informed, dull,
spiritless teacher. Let it be his happy lot, if possible, to be under
one who has some higher ambition than merely to go through a certain
prescribed routine of duties and lessons; one whose face beams with
intelligence and whose lips drop knowledge; one who can cultivate in him
the disposition to inquire, by his own readiness and ability to answer
childish inquiries; who can lead the inquiries of a child into p