and ipecac;
the universal practice of starving or "reducing" fevers by a diet of
slops, were all obvious survivals of the expulsion-of-the-demon theory
of treatment. Their chief virtue lay in their violence and
repulsiveness. Even to-day the tendency to regard mere bitterness or
distastefulness as a medicinal property in itself has not entirely died
out. This is the chief claim of quassia, gentian, calumbo, and the
"simple bitters" generally, to a place in our official lists of
remedies. Even the great mineral-water fad, which continues to flourish
so vigorously, owed its origin to the superstition that springs which
bubbled or seethed were inhabited by spirits (of which the "troubling of
the waters" in the Pool of Bethesda is a familiar illustration). The
bubble and (in both senses) "infernal" taste gave them their reputation,
the abundant use of pure spring water both internally and externally
works the cure, assisted by the mountain air of the "_Bad_," and we
sapiently ascribe the credit to the salts. Nine-tenths of our cells are
still submarine organisms, and water is our greatest panacea.

Then came the great "humoral" or "vital fluid" theory of disease which
ruled during the Middle Ages. According to this, all disease was due to
the undue predominance in the body of one of the four great vital
fluids,--the bile, the blood, the nervous "fluid," and the lymph,--and
must be treated by administering the remedy which will get rid of or
counteract the excess of the particular vital fluid in the system. The
principal traces of this belief are the superstition of the four
"temperaments," the _bilious_, the _sanguine_, the _nervous_, and the
_lymphatic_, and our pet term "biliousness," so useful in explaining any
obscure condition.

Last of all, in the fullness of time,--and an incredibly late fullness
it was,--under the great pioneer Virchow, who died less than a decade
ago, was developed the great cellular theory, a theory which has done
more to put disease upon a rational basis, to substitute logic for
fancy, and accurate reasoning for wild speculation, than almost any
discovery since the dawn of history. Its keynote simply is, that every
disturbance to which the body is liable can be ultimately traced to some
disturbance or disease of the vital activities of the individual cells
of which it is made up. The body is conceived of as a cell-state or
cell-republic, composed of innumerable plastid citizens, and its
govern