the construction of a clock intended for
astronomical observations. Pecquet, while he was
still a student, discovered the reservoir which
bears his name, the reservoir of the Chyle.
Harvey was fifty when he published the most
remarkable work on modern physiology, his book
on the Circulation of the Blood. Buffon was
seventy-one when he wrote the most perfect of
his works, the Epochs of Nature. It is easy to
conceive that a young man may discover an
unforeseen and brilliant fact; all that is required
for such spontaneous efforts is a prompt
penetration, a sudden inspiration, which are the
natural property of youth. But to discover, for
instance, the circulation of the blood, which is
the complicated result of a multitude of diverse
facts, there must be a capacity of thought and
attention, a power of combination, which belong
only to mature age.

Of Cornaro's Discorsi della Vita Sobria, the
first was written at eighty-three, the second at
eighty-six, the third at ninety-one, the fourth at
ninety-five. The whole four are little more than
the repetition of one another; but this repetition
is not wearisome, for, as the object is to
prove that the duration of life depends on
sobriety, the longer the book goes on repeating
itself the more it proves. The author himself
gracefully says, "It is true that I have nothing
new to tell you on this subject, but I have never
told it you at ninety-one." In fact, to be able
to say, at ninety-one years of age, "I will
inform you, then, that a few days ago several
doctors of your university (Padua), both of
medicine and philosophy, came to learn from my
own mouth the system of diet which I have
adopted, and that they were very much
astonished to see me still full of vigour and health;
that all my senses are perfect; that my memory,
my heart, my judgment, the sound of my voice,
and my teeth, have not altered since my youth;
that I write with my own hand seven or eight
hours a day; and that I spend the rest of my
time in taking walks, and in enjoying all the
pleasures which are permitted to a respectable
man, even including music, in which I take my
part very creditably. Ah, how you would
admire my voice, if you were to hear me sing the
praises of God to the accompaniment of my
lyre!"

    Though I look old, yet I am strong and lusty;
     For in my youth I never did apply
     Hot and rebellious liquors in my blood;
     Nor did I with unbashful forehead woo
     The means of weakness and debility;
     Therefore my age is as a lusty winter,
      Frosty, but kindly.

To be able to say this at ninety-one proves
more than saying it at eighty-six, or at eighty-
three; and repeating it at ninety-five proves
still more. But Cornaro might have made the
same boast at a hundred. One of his grand-
nieces, a nun at Padua, tells us, in a Notice which
she dedicated to her uncle's memory, that he
remained healthy and even vigorous up to a
hundred. His mind was not enfeebled; he
never had occasion for spectacles, and he did
not become deaf. And, what is not less true
than it is hard to believe, his voice remained so
strong and melodious that, towards the close of
his days, he sang quite as agreeably as he had
done at twenty.

The important question which his book raises
is that of the duration of human life. Are
there any means of prolonging that duration?
If, by prolonging it, is meant the making it
extend as far as is compatible with man's
constitution, we may reply affirmatively, that there
are means, very certain in their effect, and
which are no other than those which Cornaro
practised—sobriety, life in accordance with
reason, good conduct. But as to prolonging it
so as to make it extend beyond the limit
marked by the constitution of man, we may
believe that we should be seeking an impossibility.
For every species of animal there is a fixed and
determinate length of life. This length of life
may, in some degree, be measured by that of
the time of growth. An animal which requires
but little time to attain its full stature dies at a
much earlier age than another which requires a
longer period to grow in. According to Buffon,
man, when he is not killed by disease or accident,
lives eighty or a hundred years. Cornaro held the
same opinion respecting the length of human life,
although for less learned reasons. "When a
man," he says, "has come to forty or fifty years,
he ought to know that he has lived the half of
his life. I feel the certitude of living more than
a hundred years." He believed that people
born with "a good complexion" ought to go as
far as six times twenty years; and it is only
because he was not so well constituted as
others that he consented to reduce his hopes of
life to "scarcely more than a century."

According to M. Flourens, the life of man is
divided into two nearly equal portions—the
period of increase and the period of decrease.
Each portion is again subdivided into two others,
which give us, thus, four ages: infancy, youth,
manhood, and old age. Lastly, each of these
is also divided into two ages. There is a first
and second infancy, a first and second youth,
a first and second manhood, a first and last old
age. There are, therefore, altogether, eight,
instead of seven, ages, or acts, of man, during
which, in his time, he plays many parts.

The first age, from birth till ten years old,
before which time the second dentition is not
complete, is the infancy proper; the second
infancy, from ten to twenty, when the development
of the bones and the consequent increase
of the body in length is completed, is the
adolescence. The first youth lasts from twenty
to thirty; the second, from thirty to forty,
because the increase of the body in size and
stoutness continues till about that age. The
first manhood, or epoch of strength, or virile
period in the life of man, is comprised between
forty and fifty-five; the second, from fifty-five
to seventy. After the growth, or, more
accurately, the development in length, after the
development in thickness, M. Flourens points