owable." To do this, the physician must travel beyond the beaten path
of etiology as found in our text-books. He must follow Hutchinson in the
train of reasoning that elucidates the pre-cancerous stage of cancer, or
tread in the path followed by Sir Lionel Beale, in finding that the
cause of disease depends on a blood change and the developmental defect,
or the tendency or inherent weakness of the affected part or organ; to
fully appreciate the inherent etiological factors that reside in man,
and which constitute the tendency to disease or premature decay and
death, we must also be able to follow Canstatt, Day, Rostan, Charcot,
Rush, Cheyne, Humphry, or Reveille-Parise into the study of the
different conditions which, though normal, are nevertheless factors of a
slow or a long life. We must also be able to appreciate fully the value
of that interdependence of each part of our organism, which often, owing
to a want of equilibrium of strength and resistance in some part when
compared to the rest, causes the whole to give way, just as a flaw in a
levee will cause the whole of the solidly-constructed mass to give way,
or a demoralized regiment may entail the utter rout of an army. As
described by George Murray Humphry, in his instructive work on "Old
Age," at page 11:--

"The first requisite for longevity must clearly be an inherent or inborn
quality of endurance, of steady, persistent nutritive force, which
includes reparative force and resistance to disturbing agencies, and a
good proportion or balance between the several organs. Each organ must
be sound in itself, and its strength must have a due relation to the
strength of the other organs. If the heart and the digestive system be
disproportionately strong, they will overload and oppress the other
organs, one of which will soon give way; and, as the strength of the
human body, like that of a chain, is to be measured by its weaker link,
one disproportionately feeble organ endangers or destroys the whole. The
second requisite is freedom from exposure to the various casualties,
indiscretions, and other causes of disease to which illness and early
death are so much due."

In following out our study of diseases, we have been too closely
narrowed down by the old symptomatic story of disease; we have too much
treated surface symptoms, and neglected to study the man and his
surroundings as a whole; we have overlooked the fact that there exists a
geographical fatalism in a phys