PART I

THE INVESTIGATION OF OLD AGE

I

THE PROBLEMS OF SENILITY

Treatment of old people in uncivilised countries.—Assassination of old people in civilised countries.—Suicide of old people.—Public assistance in old age.—Centenarians.—Mme. Robineau, a lady of 106 years of age.—Principal characters of old age.—Examples of old mammals.—Old birds and tortoises.—Hypothesis of senile degeneration in the lower animals 1

II

THEORIES OF THE CAUSATION OF SENILITY

Hypothesis of the causation of senility.—Senility cannot be attributed to the cessation of the power of reproduction of the cells of the body.—Growth of the hair and the nails in old age.—Inner mechanism of the senescence of the tissues.—Notwithstanding the criticisms of M. Marinesco, the neuronophags are true phagocytes.—The whitening of hair, and the destruction of nerve cells as arguments against a theory of old age based on the failure of the reproductive powers of the cells 15

III

MECHANISM OF SENILITY

Action of the macrophags in destroying the higher cells.—Senile degeneration of the muscular fibres.—Atrophy of the skeleton.—Atheroma and arterial sclerosis.—Theory that Old Age is due to alteration in the vascular glands.—Organic tissues that resist phagocytosis. 25