much, instead of the precise number and
quantity.

Now, if there is anything on which the biological sciences have prided
themselves in these latter years it is the substitution of quantitative
for qualitative formulae. The "numerical system," of which Louis was the
great advocate, if not the absolute originator, was an attempt to
substitute series of carefully recorded facts, rigidly counted and
closely compared, for those never-ending records of vague, unverifiable
conclusions with which the classics of the healing art were overloaded.
The history of practical medicine had been like the story of the
Danaides. "Experience" had been, from time immemorial, pouring its
flowing treasures into buckets full of holes. At the existing rate of
supply and leakage they would never be filled; nothing would ever be
settled in medicine. But cases thoroughly recorded and mathematically
analyzed would always be available for future use, and when accumulated
in sufficient number would lead to results which would be trustworthy,
and belong to science.

You young men who are following the hospitals hardly know how much you
are indebted to Louis. I say nothing of his Researches on Phthisis or
his great work on Typhoid Fever. But I consider his modest and brief
Essay on Bleeding in some Inflammatory Diseases, based on cases carefully
observed and numerically analyzed, one of the most important written
contributions to practical medicine, to the treatment of internal
disease, of this century, if not since the days of Sydenham. The lancet
was the magician's wand of the dark ages of medicine. The old physicians
not only believed in its general efficacy as a wonder-worker in disease,
but they believed that each malady could be successfully attacked from
some special part of the body,--the strategic point which commanded the
seat of the morbid affection. On a figure given in the curious old work
of John de Ketam, no less than thirty-eight separate places are marked as
the proper ones to bleed from, in different diseases. Even Louis, who
had not wholly given up venesection, used now and then to order that a
patient suffering from headache should be bled in the foot, in preference
to any other part.

But what Louis did was this: he showed by a strict analysis of numerous
cases that bleeding did not strangle,--jugulate was the word then
used,--acute diseases, more especially pneumonia. This was not a
reform,--it was a revolution. It was followe