_could_ be better.

Many people dread schools for fear of wrong talk going on; now some of you
may (through gossip, or newspapers, or servants, or novels) know of bad
things or fast things; and it is perhaps not your fault that you know; but
_it is a very heavy sin on your conscience if you hand on your knowledge_
and make others dwell on wrong things which would never have been in their
minds but for you. Books or friends which give us a knowledge of
wickedness, do more harm than we know.

Never have the blood-guiltiness on your head of teaching evil to others,
or leading their minds to dwell on it. Some find it much harder to get rid
of such thoughts than others do--they may be more naturally inclined to
it, and you may have woke up in them far more harm than you guess.

Your very first duty when you are thrown with others is to see that _no
one shall ever be less nice-minded because they knew you_. See to it that
no one learns anything about evil through your being with them. You can
very easily soil a mind, and you can never wash it clean.

If you feel the least doubt about a thing, do not say it--do not tell the
story; if you want to ask a question and feel in the very least
uncomfortable about it, hold your tongue, or ask your mother instead.

There are many things which it is not wholesome to talk about among
yourselves, but which it is quite right to ask your mother about, or any
one in her place, if you find yourself dwelling on them. Of course this
includes everything which makes you feel at all hot, with a sense of
something not quite nice;--everything in books which it would make you hot
to read out loud (an excellent test);--and _I_ include all uncanny things