But there are other more formidable enemies, and against which man is
not provided with the same means of defence; I mean natural
infirmities, infancy, old age, and sickness of every kind, melancholy
proofs of our weakness, whereof the two first are common to all
animals, and the last chiefly attends man living in a state of
society. It is even observable in regard to infancy, that the mother
being able to carry her child about with her, wherever she goes, can
perform the duty of a nurse with a great deal less trouble, than the
females of many other animals, who are obliged to be constantly going
and coming with no small labour and fatigue, one way to look out for
their own subsistence, and another to suckle and feed their young
ones. True it is that, if the woman happens to perish, her child is
exposed to the greatest danger of perishing with her; but this danger
is common to a hundred other species, whose young ones require a great
deal of time to be able to provide for themselves; and if our infancy
is longer than theirs, our life is longer likewise; so that, in this
respect too, all things are in a manner equal; not but that there are
other rules concerning the duration of the first age of life, and the
number of the young of man and other animals, but they do not belong
to my subject. With old men, who stir and perspire but little, the
demand for food diminishes with their abilities to provide it; and as
a savage life would exempt them from the gout and the rheumatism, and
old age is of all ills that which human assistance is least capable of
alleviating, they would at last go off, without its being perceived by
others that they ceased to exist, and almost without perceiving it
themselves.

In regard to sickness, I shall not repeat the vain and false
declamations made use of to discredit medicine by most men, while they
enjoy their health; I shall only ask if there are any solid