heek mean to a doctor but a 'break' that ripples
above some deadly disease. Are not all her visible charms sown thick
with what are to him the signs and symbols of hidden decay? Does he
ever see her beauty at all, or doesn't he simply view her
professionally, and comment upon her unwholesome condition all to
himself? And doesn't he sometimes wonder whether he has gained most or
lost most by learning his trade?

Chapter 10 Completing My Education

WHOSOEVER has done me the courtesy to read my chapters which have
preceded this may possibly wonder that I deal so minutely with piloting
as a science. It was the prime purpose of those chapters; and I am not
quite done yet. I wish to show, in the most patient and painstaking way,
what a wonderful science it is. Ship channels are buoyed and lighted,
and therefore it is a comparatively easy undertaking to learn to run
them; clear-water rivers, with gravel bottoms, change their channels
very gradually, and therefore one needs to learn them but once; but
piloting becomes another matter when you apply it to vast streams like
the Mississippi and the Missouri, whose alluvial banks cave and change
constantly, whose snags are always hunting up new quarters, whose
sandbars are never at rest, whose channels are for ever dodging and
shirking, and whose obstructions must be confronted in all nights and
all weathers without the aid of a single light-house or a single buoy;
for there is neither light nor buoy to be found anywhere in all this
three or four thousand miles of villainous river.{footnote [True at the
time referred to; not true now (1882).]} I feel justified in enlarging
upon this great science for the reason that I feel sure no one has ever
yet written a paragraph about it who had piloted a steamboat himself,
and so had a practical knowledge of the subject. If the theme were
hackneyed, I should be obliged to deal gently with the reader; but since
it is wholly new, I have felt at liberty to take up a considerable
degree of room with it.

When I had learned the name and position of every visible feature of the
river; when I had so mastered its shape that I could shut my eyes and
trace it from St. Louis to New Orleans; when I had learned to read the
face of the water as one would cull the news from the morning paper; and
finally, when I had trained my dull memory to treasure up an endless
array of soundings and crossing-marks, and keep fast hold of them, I
judged that my