I have also found that in many women who are not perfectly well there is a notable loss of weight at every menstrual period, and a marked gain between these times.
I was disappointed not to find this matter dealt with fully in Mrs.
Jacobi's able essay on menstruation, nor can I discover elsewhere any observations in regard to loss or gain of weight at menstrual periods in the healthy woman.
How much influence the seasons have, is not as yet well understood, but in our own climate, with its great extremes, there are some interesting facts in this connection.

The upper classes are with us in summer placed in the best conditions for increase in flesh, not only because it is their season of least work, mental and physical, but also because they are then for the most part living in the country under circumstances favorable to appetite, to exercise, and to freedom from care.

Owing to these fortunate facts, members of the class in question are apt to gain weight in summer, although many such persons, as I know, follow the more general rule and lose weight.

But if we deal with the mass of men who are hard worked, physically, and unable to leave the towns, we shall probably find that they nearly always lose weight in hot weather.

Some support is given to this idea by the following very curious facts.