In meeting the uncontrollable causes of disease the special influence of
season deserves particular regard. It should always be remembered that,
other things being equal, during winter the body loses, during summer
gains in weight. Further, it should be remembered that these changes are
abrupt: that usually the loss commences, sharply, in September and lasts
until April, and that the gain commences in April and lasts until
September. In September, though the weather even be warm, it is right,
therefore, to add to the clothing and to commence a little excess of
food. In summer it is right not only to reduce the clothing, but to eat
less food than in winter.