105 mm. of mercury should be considered abnormally low, and although
150 mm. at anything over 40 has been considered a safe blood
pressure as long as the diastolic was below 105, such pressures are
certainly a subject for investigation, and if the systolic pressure
is persistently above 150, insurance companies dislike to take the
risk. However, it should be again urged in making insurance
examinations that psychic disturbance or mental tensity very readily
raises the systolic pressure. MacKenzie believes that a diastolic
pressure over 100 under the age of 40 is abnormal, and anything over
the 110 mark above that age is certainly abnormal.

It has been shown, notably by Barach and Marks, [Footnote: Barach,
J. H., and Marks, W. L.: Effect of Change of Posture--Without Active
Muscular Exertion--on the Arterial and Venous Pressures, Arch. Int.
Med., May, 1913, p 485.] that posture changes the blood pressure.
When a normal person reclines, with the muscular system relaxed,
there is an increase in the systolic pressure and a decrease in the
diastolic pressure, with an increase in the pressure pulse from the
figures found when the person is standing. When, after some minutes
of repose, he assumes the erect posture again, the systolic pressure
will diminish and the diastolic pressure increase, and the pressure
pulse shortens.

Excitement can raise the blood pressure from 20 to 30 mm., and if
such excitement occurs in high tension cases there is often a
systolic blow in the second intercostal space at the right of the
sternum. This may not be due to narrowing of the aortic orifice; it
may be due to a sclerosis of the aorta. On the other hand, it may be
due entirely to the hastened blood stream from the nervous
excitability. This is probably the case if this sound disappears