coming down" with a cold experiences,
and usually refers to a draft or a cold room, is, in nine cases out of
ten, the rigor which precedes the fever, and has nothing whatever to do
with the external temperature. The large majority of our cases of
rheumatism can give no clear or convincing history of exposure to wet,
cold, or damp. But popular impression is seldom entirely mistaken, and
there can be no question that, given the presence of the infectious
germ, a prolonged exposure to cold, and particularly to wet, will often
prove to be the last straw which will break down the patient's power of
resistance, and determine an attack of rheumatism.

This climatic influence, however, is probably not responsible for more
than fifteen or twenty per cent of all cases, and, popular impression to
the contrary notwithstanding, the liability of outdoor workers who are
subject to severe exposure, such as lumbermen, fishermen, and sailors,
is only slightly greater than that of indoor workers. The highest
susceptibility, in fact, not merely to the disease, but also to the
development of serious heart involvements, is found among domestic
servants, particularly servant girls, agricultural laborers and their
families (in districts where wages are low and cottages bad), and
slum-dwellers; in fact, those classes which are underfed, overworked,
badly housed, and crowded together. Diet has exceeding little to do with
the disease, and, so far from meat or high living of any sort
predisposing to it, it is most common and most serious in precisely
those classes which get least meat or luxuries of any sort, and are from
stern necessity compelled to live upon a diet of cereals, potatoes,
cheap fats, and coarse vegetables.

Even its relations to the weather and seasons support the infection
theory. Its seasonal occurrence is very similar to that of
pneumonia,--rarest in summer, commonest in winter, the highest
percentage of cases occurring in the late fall and in the early spring;
in other words, just at those times when people are first beginning to
shut themselves up for the winter, light fires, and close windows, and
at the end of their long period of winter imprisonment, when both their
resisting power has been reduced to the lowest ebb in the year and
infections of all sorts have had their most favorable conditions of
growth for months.

The epidemics of rheumatism, which occasionally occur, probably follow
epidemics of influenza, tonsilli