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to nearly 61,000 in 1953 and 74,790 in 1956. Although the local figures
do not show this steady rise, remaining for most years at just under 300,
the subject is one of great importance if only because, whether rising
locally or not, it is accounting for one death in six. Little definite is
known of its aetiology. The actual condition of acute myocardial
infarction is caused by a blood clot in part of the coronary artery. The
factors involved here could be the result of changes in the blood which
favour clotting, or changes in the vessel walls. Up to this, most attention
has been paid to the aetiology of the pathological changes occurring in
the tissue walls. These days it is felt that the important factors are those
which govern the thrombosis. This lesion occurs to any extent, of course,
only in those who have reached a certain age; but it is now generally
agreed that arterio-sclerosis is not naturally or inevitably a concomitant
of ageing. It is a pathological process; and the incidence of the disease
increases with age probably because the development of the lesions is
slow and because such factors as hypercholesterolaemia, obesity and
hypertension become more prominent with increasing age. One school
of thought lays special emphasis on the importance of diet as an
Etiological factor, another on the lack of exercise; a third favours stress,
though this is now a diminishing number. But even where there appears
to be a correlation of the incidence and sedentary occupation, this
association is not necessarily one of cause and effect. It may be that
both are due to some unknown third factor. Again, any association
might be accounted for by genetic characteristics, the same sorts and
conditions of men not seeking employment in the same kinds of jobs.
Many feel that diet is important. The dietary fat is by some considered
to be the most important factor, especially diets containing saturated
fatty acids which lead to a greater accumulation of cholesterol in the
blood than would be caused by a corresponding amount of unsaturated
fats. Unprocessed vegetable fats contain more unsaturated fatty acids
than most animal fats. Some see in this question of the proportion of
unsaturated to saturated fatty acids a factor of importance not only in
the aetiology of coronary thrombosis, but of leukaemia and cancer of the
lung as well, all conditions which are increasing in incidence. Present
pointers indicate that this complaint is one which arises from our eating
too much, probably too much in general rather than too much of any
particular food substance. A recent report of the American Nutrition
Committee said: "There is not enough evidence available to permit a
ngid stand on what the relationship is between nutrition, particularly the
[at content of the diet, and athero-sclerosis and coronary heart disease."
Existing evidence does not justify drastic changes in the amount or type
of fats eaten by the general public on the premise that heart disease will
be prevented thereby. (This, of course, does not apply to any particular
individual.) Existing evidence is sufficient to warrant an immediate and
comprehensive investigation of diet as one factor in the development of
athero-sclerosis. (Others may be hereditary, sex, the anatomy of the
Wood vessel wall, arterial blood pressure.) "
Deaths from Infectious Diseases
Infections once more accounted for few of the deaths in 1957. There
were again no deaths from measles or from whooping cough, diseases