of plunging through drifts as high as your head on your daily way to
school. You jingled in sleighs, you snow-balled, you lived in snow
like a snow-bird, and your blood coursed and tingled, in full tide of
good, merry, real life, through your veins--none of the slow-creeping,
black blood which clogs the brain and lies like a weight on the vital
wheels!"

To illustrate the effects of this poison, the horrors of "the Black
Hole of Calcutta" are often referred to, where one hundred and forty-six
men were crowded into a room only eighteen feet square with but two
small windows, and in a hot climate. After a night of such horrible
torments as chill the blood to read, the morning showed a pile of one
hundred and twenty-three dead men and twenty-three half dead that were
finally recovered only to a life of weakness and suffering.

In another case, a captain of the steamer Londonderry, in 1848, from
sheer ignorance of the consequences, in a storm, shut up his passengers
in a tight room without windows. The agonies, groans, curses, and
shrieks that followed were horrible. The struggling mass finally burst
the door, and the captain found seventy-two of the two hundred already
dead; while others, with blood starting from their eyes and ears, and
their bodies in convulsions, were restored, many only to a life of
sickness and debility.

It is ascertained by experiments that breathing bad air tends so to
reduce all the processes of the body, that less oxygen is demanded and
less carbonic acid sent out. This, of course, lessens the vitality and
weakens the constitution; and it accounts for the fact that a person
of full health, accustomed to pure air, suffers from bad air far more
than those who are accustomed to it. The body of strong and healthy