when the patient reclines. If it increases when the heart becomes
slower and the patient is lying down, the cause is probably organic.

This psychic influence on blood pressure is stated by Maloney and
Sorapure [Footnote: Maloney and Sorapure: New York Med. Jour., May
23, 1914, p. 1021.] "to be greater than that from posture, than that
arising from carbonic acid gas control of the blood, than that
arising from mechanical action of deep breathing upon the
circulation, and than that arising from removal of spasm from the
musculature."

Weysse and Lutz [Footnote: Weysse and Lutz: Am. Jour. Physiol., May,
1915.] find that the systolic pressure varies during the day in
normal persons, and is increased by the taking of food, on an
average of 8 mm. The diastolic pressure is not much affected by
food. This increased systolic pressure is the greatest about half an
hour after a meal, and then gradually declines until the next meal.

Any active, hustling man, or a man under strain, has a rise of blood
pressure during that strain, especially notable with surgeons during
operation, or with brokers or persons under high nervous tension.
Daland [Footnote: Daland: Pennsylvania Med Jour., July, 1913.]
states that a man driving an automobile through a crowded street may
have an increase of systolic pressure of 30 mm., and an increase of
15 mm. in his diastolic pressure, while the same man driving through
the country where there is little traffic will increase but 10 mm.
systolic and 5 mm. diastolic. Fear always increases the blood
pressure. This is probably largely due to the peripheral
contractions of the blood vessels and nervous chilling of the body.