In taking blood pressure, the cuff around the arm is inflated until it squeezes tightly enough
to prevent any blood from passing through the artery under it. As the pressure in the cuff is
allowed to drop slowly, at the height of the heart's contraction a small amount of blood can
get through, and is heard as a tapping sound. This is recorded as the systolic blood pressure.
As the pressure in the cuff is allowed to drop further, the sounds change and then die away.
The pressure at which the sounds change rapidly just before dying away is called the diastolic
blood pressure. Different observers will report slightly differiong val;ues for this.
One of the professors of medicine told us of giving a lecture at a county medical society in
western Massachusetts. After the lecture, an elderly member asked him in a patron;izing tone"
"Young man, your talk was in the main quite interesting. But what was this systole and diastole
you kept mentioning?"