tobacco, impairs the energy of the muscles somewhat as alcohol does, by
its paralyzing effect upon the nervous system. As all muscular action
depends on the integrity of the nervous system, whatever lays its
deadening hand upon that, saps the vigor and growth of the entire frame,
dwarfs the body, and retards mental development. This applies especially
to the young, in the growing age between twelve or fourteen and twenty,
the very time when the healthy body is being well knit and compacted.

Hence many public schools, as well as our national naval and military
academies, rigidly prohibit the use of tobacco by their pupils. So also
young men in athletic training are strictly forbidden to use it.[12] This
loss of muscular vigor is shown by the unsteady condition of the muscles,
the trembling hand, and the inability to do with precision and accuracy
any fine work, as in drawing or nice penmanship.



Additional Experiments.

Experiment 23. _ To examine the minute structure of voluntary
muscular fiber._ Tease, with two needles set in small handles, a bit of
raw, lean meat, on a slip of glass, in a little water. Continue until
the pieces are almost invisible to the naked eye.

Experiment 24. Place a clean, dry cover-glass of about the width of
the slip, over the water containing the torn fragments. Absorb the
excess of moisture at the edge of the cover, by pressing a bit of
blotting-paper against it for a moment. Place it on the stage of a
microscope and examine with highest obtainable power, by light reflected
upward from the mirror beneath the stage. Note the apparent size of the