suddenly too great or too rapidly acquired. In other words, if the
peripheral resistance gradually increases, the left ventricle
hypertrophies, and remains for a long time sufficient. If, from
disease or disturbance in the lungs, the resistance in the pulmonary
circulation is increased, the right ventricle hypertrophies to
overcome it, and the circulation is sufficient as long as this
ventricle is able to do the work. If either this pulmonary increased
pressure or the systemic increased pressure persists or becomes too
great, it is only a question of how many months, in the case of the
right ventricle, and how many years, in the case of the left
ventricle, the heart can stand the strain.

If the cause of the increased systemic tension is an arterial
fibrosis, sooner or later the heart will become involved in this
general condition, and a chronic myocarditis is likely to result.
If, on the other hand, there is a continuous low systemic arterial
blood pressure, the circulation is always more or less insufficient,
nutrition is always imperfect, and the physical ability of the
individual is below par. It is evident, therefore, that an
abnormally high blood pressure is of serious import, its cause must
be studied, and effort must be made to remove as far as possible the
cause. On the other hand, a persistently low blood pressure may be
of serious import, and always diminishes physical ability. If
possible, the cause should be determined, and the condition
improved.

No physician can now properly practice medicine without having a
reliable apparatus for determining the blood pressure both in his
office and at the bedside. It is not necessary to discuss here the
various kinds of apparatus or what is essential in an apparatus for