arteriosclerosis, or the gradual aging of the arteries, slows the
pulse, except when the cardiac degeneration of old age makes the
heart again more irritable and more rapid. The rapid heart in
hyperthyroidism is also well understood. It is not so frequently
noted that hypersecretion of the thyroid may cause a rapid heart
without any other tangible or discoverable thyroid symptom or
symptoms of hyperthyroidism. Bile in the blood almost always slows
the pulse.


INTERPRETATION OF TRACINGS

The interpretation of the arterial tracing shows that the nearly
vertical tip-stroke is due to the sudden rise of blood pressure
caused by the contraction of the ventricles. The long and irregular
down-stroke means a gradual fall of the blood pressure. The first
upward rise in this gradual decline is due to the secondary
contraction and expansion of the artery; in other words, a tidal
wave. The second upward rise in the decline is called the recoil, or
the dicrotic wave, and is due to the sudden closure of the aortic
valves and the recoil of the blood wave. The interpretation of the
jugular tracing, or phlebogram as the vein tracing may be termed,
shows the apex of the rise to be due to the contraction of the
auricle. The short downward curve from the apex means relaxation of
the auricle. The second lesser rise, called the carotid wave, is
believed to be due to the impact of the sudden expansion of the
carotid artery. The drop of the wave tracing after this cartoid rise
is due to the auricular diastole. The immediate following second
rise not so high as that of the auricular contraction is known as
the ventricular wave, and corresponds to the dicrotic wave in the