cited above.--Ed.

In 1857, a young man, Louis Pasteur, sent to the Lille Scientific
Society a paper on "Lactic Acid Fermentation" and in December of the
same year presented to the Academy of Sciences in Paris a paper on
"Alcoholic Fermentation" in which he concluded that "the deduplication
of sugar into alcohol and carbonic acid is correlative to a phenomenon
of life." A new era in medicine dates from those two publications. The
story of Pasteur's life should be read by every student.(*) It is one of
the glories of human literature, and, as a record of achievement and of
nobility of character, is almost without an equal.

(*) Osler wrote a preface for the 1911 English edition of the
Life by Vallery-Radot.--Ed.

At the middle of the last century we did not know much more of the
actual causes of the great scourges of the race, the plagues, the fevers
and the pestilences, than did the Greeks. Here comes Pasteur's great
work. Before him Egyptian darkness; with his advent a light that
brightens more and more as the years give us ever fuller knowledge. The
facts that fevers were catching, that epidemics spread, that infection
could remain attached to articles of clothing, etc., all gave support to
the view that the actual cause was something alive, a contagium vivum.
It was really a very old view, the germs of which may be found in the
Fathers, but which was first clearly expressed--so far as I know--by
Fracastorius, the Veronese physician, in the sixteenth century, who
spoke of the seeds of contagion passing from one person to another;(12)
and he first drew a parallel between the processes of contagion and
the fermentation of wine. This was more than one hundred years before
Kircher, Leeuwenhoek and others began to use the microscope and to see
animalcula, etc., in water, and so give a basis for the "infinitely
little" view of the nature of disease germs. And it was a study of the
processes of fermentation that led Pasteur to the sure ground on which
we now stand.

(12) Varro, in De Re Rustica, Bk. I, 12 (circa 40 B.C.), speaks
of minute organisms which the eye cannot see and which enter the
body and cause disease.

Out of these researches arose a famous battle which kept Pasteur hard at
work for four or five years--the struggle over spontaneous generation.
It was an old warfare, but the microscope had revealed a new world, and
the experiments on fermentation had lent great weight to the omne