ill tell you this. Now, under what
circumstances is a larger amount of oxygen found? What climate affords
most, all other things being equal? It certainly is not a _hot_ climate,
nor a variable moist one such as prevails all over the consumptive
district which we have indicated at the beginning of this chapter. It is
found in a cool, dry climate, and this condition is had in Minnesota
with greater correlative advantages than in any other section of the
Union known up to this time. The atmosphere is composed of two gases,
oxygen and nitrogen, and in every one hundred parts of common air there
are about seventy-five parts of nitrogen and twenty-five of oxygen,
subject to expansion from heat and of contraction from cold. This
accounts in part for the general lassitude felt in a warm atmosphere,
while a corresponding degree of vigor obtains in a cold one. The
condensation, the result of a cool temperature, gives to the lungs a
much larger amount of oxygen at a single inspiration, and, of course,
for the day the difference is truly wonderful. The blood is borne by
each pulsation of the heart to the air-cells of the lungs for
vitalization by means of the oxygen inhaled--the only portion of the air
used by the lungs--giving it a constantly renewing power to energize the
whole man. If a cold climate is attended with great humidity, or raw,
chilling winds, the object is defeated and the diseased member
aggravated, as would also be the case even if the climate was not a
cold, raw one, but was a _variable_ cold one; as then the sudden changes
would induce colds, pneumonia, and all the train of ills which terminate
in this dire calamity we are so anxious to avoid.

_Equability_ and _dryness_ are the essentials of a climate in which
consumptives are to receive new or lengthened leases of life.

The following testimony is of such a high value that no apology need be
offered for its introduction here. It is, in the first case, from one
who was sick but is now well, and, in the other, from a party whose
observation and character give weight to opinions.

The able and celebrated divine, the Rev. Horace Bushnell, D.D., of
Hartford, Conn., in a letter to the _Independent_, says:--

"I went to Minnesota early in July, and remained there till the latter
part of the May following. I had spent a winter in Cuba without benefit.
I had spent also nearly a year in California, making a gain in the dry
season and a partial loss in the wet season