thought of which already haunted him, he allowed him-
self to be seduced by the idea of studying the manufac-
ture of beer. Was it not possible to make it in France
as well as in Germany, and to free us through science
from paying tribute to the breweries across the Rhine?
Such was the ambition that took possession of him little
by little as he penetrated more and more into this diffi-
cult subject. To-day we may say that this ambition
has been realized as much by the efforts of Pasteur as
by the intelligent activity displayed by the French
brewers. At the present time, the best French beers
are equal to the best German or Austrian beers, and for
this progress the French brewers, in the Congress of
1889, gave the honor and credit to the labors and to the
book of Pasteur on beer.

This book is not an ordinary book, not a kind of
theoretical treatise on brewing. It reflects so clearly
the varied preoccupations of Pasteur at this stage of his
existence, that I am obliged to draw attention to its
somewhat eccentric composition. Of brewing there is
very little said. The first chapter shows that the dis-
eases of beer are always due to the development of
microscopic organisms foreign to a good fermentation,
not at this time a new idea. The last chapter gives the
means of making pure and unalterable beers. And it
seems, in reality, that this is sufficient, and that one
might be content with saying to the brewers: This is
why your beers are bad, and here is the means of making
good ones!

It was, in fact, in these relatively simple terms that
Pasteur stated the problem in the beginning. But he
was not slow to see that the question was much more
complicated. An egg of a silkworm developed accord-
ing to a scientific formula is surely a good egg. A beer
protected from pathogenic ferments during its manufac-

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