Later and wiser investigation has proved it to be so much controlled by
climate that it may be practically located on a chart of the globe, if
all the climatic conditions are fully known. Of course, it is not
absolutely confined to any given limit, more than is the yellow fever,
which sometimes makes its appearance as high as the forty-second degree
of latitude, while its actual home, so to speak, is, on this continent,
below the thirty-fifth parallel.

In a medical chart of this country, which we had occasion to examine
many years since, the district where consumption attained its maximum
range was outlined along the coast, beginning with the State of Maine,
having a semi-circular sweep to Fortress Monroe in Virginia, with an
inland limit varying from one to two hundred miles. This is well known,
now, to all the medical profession, to be the territory where _phthisis
pulmonalis_ has greatest sweep, and this is conceded to be, for the most
part, caused by the marked peculiarities of climate existing over all
this area. These peculiarities have, in some of the immediately
preceding chapters, been duly though briefly set forth, and we now
proceed to the consideration of the sanitary value of the Minnesota air
and its effects on lung diseases as experienced by sufferers and
observed by others, together with some of its leading characteristics.

If it has been sufficiently shown that the temperature of the district
in which consumption prevails most is a highly variable one, passing
almost daily from a low to a high point in the thermometric scale, with
the prevailing winds to be those in which east largely enters; and that
these winds come laden with a cold moisture, borne from off the surface
of the North Atlantic, which, when exposed to their sweep, chill the
person and pave the way to colds, catarrhs, rheumatism, pneumonia, and a