others, is not constant in a considerable degree in old people, and
therefore cannot, as Demange and others considered, be regarded as
the cause of the atrophic changes seen in old age. Arteriosclerosis
is due to several factors, namely, infection and intoxication of
various kinds and to damage caused by long-continued high arterial
blood pressure. The primary changes are degeneration and weakness,
however brought about, in the middle coat. Ophülz[161] has recently
discussed the question whether the degeneration is entirely or largely
a senile change; if it were so, the curve of the incidence of arterial
sclerosis would begin gradually about the age of 40 years, so as to
include premature cases, and rise slowly until the age of 55 years,
when there would be a sudden increase to 80 or 90 per cent, and at
the age of 70 it would be improbable that any one would be free from
well-marked arteriosclerosis. He found that the curve of incidence was
very different from this; beginning much earlier its rise is gradual
all the way without any sudden increase, and indeed seems, if anything,
to be retarded by old age. Old persons may have practically healthy
arteries, so, although arteriosclerosis may undoubtedly produce atrophy
and senile changes in the tissues and organs by diminishing the blood
supply, for example in the case of the red granular kidney, it cannot
be regarded as the causal factor in healthy old age.
The primary calcification of the middle coat, sometimes called
Mönckeberg’s sclerosis, which leads to the formation of regular
rings in the degenerated muscular media and the “pipe-stem” arteries
associated with senile gangrene, may be independent of, or combined
with, endarterial sclerosis. It follows fatty degeneration of the
media, which is the commonest form of medial degeneration in the aged,
and specially picks out the elastic fibres.[162] The femoral, tibial,
radial arteries and the aorta are most often affected. It is difficult
to estimate its incidence, but that it is not very common, at any rate
in a high degree, seems probable from the comparative infrequency of
its detection in _x_-ray examinations of the lower limbs in old people.
It would be natural to associate its occurrence with the rarefaction of
bone that goes on in advanced life, and so to consider it as in some
respects different from the secondary calcification in endarteritic
sclerosis; in answer to an enquiry Professor W. T. Councilman of
Harvard kindly wrote to me that he did not regard calcification as
characteristic of any particular type of arterial disease, lime salts
being in certain cases more easily deposited in any pre-existing
lesions. Klotz describes fatty and calcareous change in the middle
third of the media of the aorta as quite characteristic of senescence.
Cazalis’s famous aphorism “man is as old as his arteries” is true in
so far that the state of the arteries is a good index of the general
condition, for they are extremely prone to suffer as the result of
infection, toxaemia, and strain; strictly speaking, therefore, the
state of the arteries is not so much an index of the individual’s age
as of his adventures.
Phlebosclerosis, analogous to arteriosclerosis, is common, and
dilatation, often due to stagnation and lack of the normal _vis a
tergo_, of the veins is a familiar change in the aged.
The capillary area is diminished in the skin and elsewhere, but not
uncommonly there are dilated venules or angiomas on the skin; the
latter, commoner on the trunk and upper limbs and in men, were formerly
known as “de Morgan’s spots” and were thought to accompany cancer, but
the association is only due to a rough correspondence of their age
incidence.
_The blood_ of healthy octogenarians may not show any departure from
that of the earlier periods of life as regards the number of the reds
and the amount of haemoglobin (Hansen[163]), though some have described
a secondary anaemia. Thus in a female centenarian Macnaughton[164]
found slight secondary anaemia with a normal number of leucocytes,
the differential count showing a relative lymphocytosis. The red bone
marrow diminishes, its place being taken by fat cells.
_The lymphoid tissues_ undergo atrophy all over the body including the
leucoblastic bone marrow, but though it does not appear that the blood
shows any definite change in the leucocyte count it is tempting to
correlate the diminution of resistance to acute infections, such as
pneumonia and erysipelas, with the atrophy of the lymphoid tissue. The
alimentary canal often shows lymphoid atrophy in a high degree, but two
normal Peyer’s patches were present in a man reputed to be 106 years
old (G. Rolleston[165]).
_The spleen_, in common with the lymphoid tissues elsewhere, shows
atrophy, sometimes to an extreme degree, so that instead of the normal
weight of 7 oz. it weighs a few drams only. The capsule is thrown into
folds, and is somewhat opaque; from atrophy of the pulp and Malpighian
corpuscles the vessels and fibrous trabeculae become prominent. _The
thymus_, contrary to the general opinion that it undergoes involution
long before puberty, has been found by Hammar[166] to increase in size
up to puberty when involution begins, but proceeds so gradually that
even in old age it is functional.
The _thyroid_, unless there is cystic change, is smaller than
natural; thus out of 40 thyroid glands from individuals between the
ages of six months and 77 years the smallest was in a woman aged 77
(Hale-White[167]). In colour it is darkish brown and on section rather
dry. Dr. Donaldson, Lecturer on Pathology at St. George’s Hospital, has
specially examined 19 thyroid glands from patients between the ages of
57 and 93; of these five showed cystic change; they all showed increase
in the amount of fibrous tissue which was progressive with age, and in
the absence of cystic change the size of the vesicles and amount of
colloid material were diminished.
_The Parathyroids._--From examination of a number of specimens Dr.
Donaldson finds that in old people the parathyroids appear to be
free from retrogressive changes, but he cautiously requires further
experience before concluding that this is the rule.
The _adrenals_ show involutionary atrophy in common with the body as
a whole, but sometimes the cortex is enlarged from excess of lipoids,
usually associated with considerable atheroma, and may also show
adenomas. As the increase in size of the adrenals is cortical its
relation to high blood pressure, if any, is that of a remote result,
namely from arteriosclerosis, and not causal as has been suggested.
According to G. M. Findlay[168] the amount of lipochrome in the cells
of the adrenals increases with advancing years and is accompanied by
the appearance of melanin in their nuclei.
The _kidneys_ show definite atrophy, and Councilman,[169] who has
recently made a study of them in 580 persons over 60 years of age,
calls the condition chronic atrophic nephropathy. The fat in the renal
pelvis is more obvious than usual, the capsules are slightly thickened
and occasionally but by no means always adherent, the surface finely
rough and sometimes showing small cysts, but the large and irregular
depressions characteristic of a granular kidney are not common. There
are, however, areas of fibrosis, and the cortex and medulla are equally
atrophied. Microscopically some glomeruli are fibroid, others smaller
than natural. In three-fourths of his cases the renal vessels showed
arteriosclerosis due to primary atrophy of the media with compensatory
hypertrophy of the intima; but Councilman gives reasons for hesitation
in accepting the obvious conclusion that the senile kidney is the
result of the vascular change.
_The prostate_ shows some degrees of enlargement after the age of
fifty in the vast majority of men, but in only a percentage of
these are there symptoms referable to it. Kenneth Walker[170] finds
that the maximum size is reached at the age of 60 and that from then
onwards there is a slow diminution in size; among 340 men between
80 and 90 there were 11, or 3·2 per cent, and among 92 men between
90 and 100 one only with hypertrophy of the prostate (Humphry). The
causation of prostatic hypertrophy has been much discussed; that its
association with arteriosclerosis (Launois[171]) is anything more than
a coincidence, the two conditions being common in the later years of
life, seems improbable; Walker found the two associated in 10 per
cent, and he regards the change as part of a general enlargement
and thickening of the peri-urethral, sub-cervical, and sub-trigonal
glands, and, as the interstitial cells in the testes become fewer
and degenerated, he considers that the prostatic enlargement is
possibly a degeneration connected with a disturbance of the endocrine
balance. Nemenow[172] argued that prostatic enlargement was due to
proliferation of the interstitial cells following senile atrophy
of the seminal tubules of the testes, but K. Walker found that in
prostatic enlargement the interstitial cells are diminished rather than
increased in number. An interesting parallel has been drawn between
the involutionary changes in the mamma and the prostate, and it is
probable that the same underlying factor is at work in both (Walker,
Paul). Hertoghe[173] regarded some cases of prostatic hypertrophy as
due to senile dysthyroidism, and recently benefit has been reported
from thyroid medication and also from prostatic extract. Dr. Leonard
Williams has told me of cases, as yet unpublished, showing well-marked
relief of symptoms and diminution in the size of prostatic enlargement
after doses of thyroid extract (½ grain once) and colloidal iodine
(one dram three times) daily. The prostatic plexus of veins is often
enlarged and may contain phleboliths.
The _testes_ become smaller, softer, and commonly show some atrophy of
the tubules with disappearance of the epithelial lining and thickening
of the basement membrane; but the testes of old men may be free from
any such change and the spermatozoa in the vesiculae seminales may
be active. According to K. Walker the interstitial cells gradually
diminish in number from the age of 30, but they may be present in men
over 80, and Mott[174] remarks that their persistence may account for
an increased and perverted sexual appetite, due to stimulation of the
desire without the power to perform the sexual act.
The _penis_ becomes smaller, often retracted, the _glans_ harder, and
the _scrotum_ smaller.
The _ovaries_ become shrivelled and fibrotic; the ova disappear
or small cysts may form. It is difficult to find statements about
the presence or absence of interstitial cells in the senile ovary.
Professor Turnbull has kindly informed me that in old women an
occasional cell which might be, but is not certainly, an interstitial
cell is visible, and that if they are interstitial cells their number
must be small and their development poor.
The _uterus_ becomes small, its cavity round, and the cervical canal
may be obliterated. The _external genitals_ atrophy.
The _mamma_ in women shows involution changes and when excessive
(cystic disease) these may, as Paul[175] has pointed out, be compared
with prostatic enlargement in the male.
VII
PHYSIOLOGY OF OLD AGE
The basis of the physiology of old age is progressive diminution in
functional activity, which corresponds to the characteristic structural
atrophy of the organs and tissues. Thus the lowered functional activity
of its glands is manifest in the dry skin; according to Haneborg[176]
there is usually a fall in the percentage of hydrochloric acid in the
gastric juice, though Bell[177] disputes this. The lessened amount of
mucus from the intestine probably plays some part in the tendency to
constipation. Other evidences of lowered metabolic rate are seen in
the diminished efficiency of the acid-base equilibrium (MacNider[178])
and the increased degree of urea-nitrogen in the blood, as shown in
50 per cent of 41 persons between 70 and 88 years of age examined by
Rappleye.[179]
_Temperature._--Before the era of the clinical thermometer it was
supposed that the body temperature of the aged was below normal. This
belief was part of the ancient view that the cause of old age was
exhaustion by the natural heat of the radical moisture which, like lamp
oil, supported the innate heat and with the passage of years could not
be supplied as perfectly as before; as a result of this loss of radical
moisture the body was thought gradually to dry and cool.[180] But it is
now known that the internal temperature is almost constant at all ages,
and Charcot proved that the only real difference is that the axillary
is lower than the rectal reading; this is due to the diminished
vascularity of the skin and to the corresponding fall in the loss of
heat, which again may be correlated with the lower metabolic rate of
old age. Aub and Dubois’[181] observations on six men between 77 and
83 years of age, mainly with arteriosclerosis, granular kidney, and
emphysema, showed that the basal metabolism was 12 per cent below the
average for men between 20 and 50.
Blunting of sensibility to pain is a beneficent process, suggesting
that with the gradual process of involution and approach to a
physiological death the need for the warning normally conveyed by
symptoms is no longer needed. This is connected with the simultaneous
atrophy of the nervous tissues which look after the conduction,
perception, and reference of pain. The latency of disease, as shown by
an absence of the characteristic symptoms observed in earlier adult
life, is often remarkable in the aged. Thus death may occur suddenly
from extensive but entirely unsuspected pneumonia; the passage of
biliary or urinary calculi may be unaccompanied by the violent colic
of these events in ordinary cases, and extensive malignant disease may
exist without any definite localizing discomfort. This failure in the
power to react is also shown in fevers and infections (_vide_ p. 142).
Cutaneous sensation is little affected, and indeed the aged are very
sensitive to cold. Taste and smell are impaired, and presbyopia is due
to changes in the crystalline lens. The pupils are contracted and the
iris sluggish. From weakness of the orbicularis palpebrarum muscle
ectropion and epiphora may noticeably change the facial appearance.
With advancing years hearing commonly becomes less acute from various
causes, and after 60 there is a successive decrease in the number
of persons with normal hearing. According to Albert Gray[182] there
is probably a characteristic form of deafness for the higher notes
of Galton’s whistle in all old people, even when for all practical
purposes there is no obvious defect or tinnitus; this he regards as due
to progressive atrophy of the ligamentum spirale. Chronic progressive
labyrinthine deafness, due to atrophy of the auditory nerve and
fibrosis of the ductus cochleariae, is the most common condition in
persons over 60. Fixation of the stapes frequently causes deafness,
and the sequels of middle-ear disease accumulate with advancing years.
Gouty eczema of the external auditory meatus and collections of wax may
seriously interfere with hearing. Tinnitus in the elderly is commonly
associated with high blood pressure and arteriosclerosis.
_Appetite_ for food is sometimes capricious; old people may eat
excessively, possibly because the pleasures of the table are the only
ones to which they feel equal.
_Muscular movement_ is slow and somewhat uncertain, and the reflexes
are diminished except in the presence of sclerosis of the spinal cord.
According to Moebius the _knee-jerk_ is often absent in normal old
persons, but Sternberg, by employing methods of reinforcement not
available in Moebius’ time, found that it was invariably present even
in the tenth decade.
The _sleep_ of the aged is less continuous, and from interruptions
often appears to them to be much less than it really is. There is
often a tendency to irregularity, bad and good nights alternating. But
too much attention to disturbed sleep in the aged must be avoided, as
hypnotics are inadvisable, and it has been urged by Sir Hermann Weber
and others that too much sleep is more harmful than too little.
In old age the _mental condition_ varies in different individuals
according to their previous character and their present physical state.
Freedom from sexual and other perturbations often renders the minds of
old people calm, tolerant, less susceptible to disappointed ambition,
and philosophic when the part of spectator has been accepted in place
of that of actor in life’s drama. In what may be regarded as normal old
age psychical activity diminishes; not only do initiative, elasticity,
and originality fail, but new ideas and fresh lines of thought are
assimilated with difficulty; hence the old are commonly conservative
and _laudatores temporis acti_. Mental fatigue occurs more readily and
the power of concentration and attention is impaired so that the old
may appear deaf; the mind begins to show disintegration and a return to
the primitive condition in which each act demands individual care; it
has indeed been said that old age is nothing but progressive fatigue.
A less agile memory for names is commonly one of the early symptoms of
senescence, and long precedes the characteristic loss of memory for
recent events while that for the remote past remains, as if the nerve
cells were photographic plates which in course of time have all become
occupied with impressions. With commencing failure of memory there
is often a tendency to make the same remark or tell the same story
repeatedly, to mislay things, and unconsciously to become careless
about personal appearance and habits. As a kind of protest against the
inevitable there may, in the early stage of old age, be a tendency
to ape the young and to conceal the true age; thus a man may remove
the date of his birth from _Who’s Who_ and books of reference, and a
mother may delay the “coming-out” of her daughter. On the other hand,
at a later stage there may be the opposite desire to appear a wonderful
prodigy of senescence. The old are notoriously less subject to feel the
loss of relatives and friends by death; they become more self-centred;
this may be because retirement from active work switches their minds on
to their own feelings, and possibly in part depends on loss of touch
with the external world, resulting from failure of the sense organs.
This when exaggerated develops into selfish dependence and demands on
relatives. Senile vanity is not uncommon, and Eden Phillpotts[183]
remarks that all old people love to be in the centre of the stage, one
of the pathetic things in life being that they are seldom allowed to
be there. The ego-centric frame of mind may lead to hypochondriasis
with fads and meticulous attention to details of personal health and
to experiments in diet and patent medicines. Loss of control, due to
failure of the higher centres, engenders restlessness, garrulity,
emotional weakness, and peevishness. There may be considerable
variation in the moods, so that the deep depression of one day may
vanish the next, and irritability and apathy may alternate.
Regression, which closely corresponds to the “devolution” of Hughlings
Jackson, who argued that in disease the organism tends to retrace the
steps of its development, accounts for the phenomena of “the second
childhood.” Thus the old are prone to nervous apprehension, and liable
to suggestion and to hysteria which Rivers[184] defined as a protective
mechanism representing a recrudescence of the reaction to danger in an
early stage of animal development. Will power, like their gait, becomes
hesitant and uncertain. This devolutionary change progresses partially
and not universally; memory for personal names, as mentioned above, is
often the first to fail, because, like the mathematical faculty, it
has from the attendant difficulty a high place in the order of mental
processes; hence forgetfulness of personal names is a criterion of
psychical fatigue and neurasthenia (Dupuis[185]).
In old animals it is natural for the instinct of self-preservation to
fade, as is exemplified in the day-flies which in their larval stage
are well endowed with this property, and as their end draws near
animals seem to acquire an instinct for death comparable to that for
sleep. But in human beings, although they usually dislike old age,
there is generally what Matthew Arnold[186] called “a passionate,
absorbing, almost bloodthirsty clinging to life.” Metchnikoff specially
investigated this point and found hardly any instances in which death
was anticipated with the same feelings of pleasure as is sleep by the
weary. Considering the discomforts of many old people it is rather
remarkable how very seldom they endorse the words of the burial
service: “We give thee hearty thanks for that it hath pleased thee to
deliver this our brother out of the miseries of this sinful world.”
Various explanations have been offered for this want of harmony between
the mental and physical states of the old; it has been ascribed to
the idea of eternal punishment, and to the presence of pathological
conditions which bring on senility and death prematurely and thus
alter what should be the normal mental attitude of healthy old age.
In speaking of the usual fear of death in old people it should be
mentioned that shortly before death this commonly disappears and, as
G. E. Day,[187] R. W. Mackenna,[188] and Thompson and Todd point
out, the aged when seriously ill commonly regard death as a welcome
release; the famous William Hunter’s last words in his sixty-fifth year
expressed his sense of resignation: “If I had strength enough to hold a
pen, I would write how easy and pleasant a thing it is to die.”
_The Cardio-Vascular System._--The pulse rate is usually rather
increased in frequency as compared with that in adult life;
extra-systoles are so common in persons who appear otherwise normal
that they cannot be regarded as having any important significance.
Among Sir George Humphry’s collection of 824 persons over 80 years of
age one-fifth had an irregular or intermittent pulse.
Although, like arteriosclerosis, a well-marked high blood pressure
without evidence of renal disease, to which Sir Clifford Allbutt
has given the name of senile plethora or hyperpiesia, is common in
the decline of life, it is a pathological and not a physiological
change; and a distinction must be drawn between the gradually rising
blood pressure seen from birth onwards and an increase above that
normal to an arterio-vascular system that has been active for over
half a century. In the same way the venous pressure increases with
age (Hooker[189]). That a definitely high blood pressure in the
aged is pathological appears to be shown by observations quoted by
Councilman from the Peter Bent Brigham Hospital, Boston; among 94
patients (male and female) averaging 66 years of age, 44 per cent
with cardiac hypertrophy as shown by necropsy, had an average blood
pressure of 158 systolic / 88 diastolic, whereas the 56 per cent
without cardiac hypertrophy had an average blood pressure of 130/78.
In both series the differences between males and females were never
more than 7 mm. Hg. From observation of 102 Chelsea pensioners over 75
years of age Thompson and Todd found that the average blood pressure
was 145 systolic / 80 diastolic, estimations varying from 190/100 to
115/70, and that the average pulse pressure, or difference between
the systolic and diastolic pressures, was 67 mm. They came to the
conclusion that it was not possible to arrive at a normal blood
pressure for old people on account of the varying conditions of the
heart and arteries.[190]
The urine, in consequence of the lowered metabolism and general
atrophy, is somewhat diminished in quantity with a fall in the solids,
though the specific gravity remains about normal. The chlorides are
stated to be normal and the phosphates and urea to be diminished.
Slight glycosuria as a result of a low sugar tolerance (_vide_
Spence[191]) is not uncommon, especially in obesity. Prolonged
confinement to bed has been thought to be responsible for casts in
the urine. A trace of albumin is not rare; this may be due to various
factors, and in itself is not a cause for anxiety; but a well-marked
fall in the specific gravity is a sign of renal inadequacy which may be
preceded and anticipated by the discovery of nitrogen retention in the
blood.