This is an excerpt from the Discovery Channel production How Beer Saved the World.

Beer was the basis of modern medicine. It all started in 1850s with scientist Louis Pasteur. He invented pasteurization. Tragically, people always link him to this, milk. But he was actually studying this: beer. Some people think he was looking at milk, but in fact, he was actually looking at beer and beer was the first beverage, actually, to be pasteurized. Pasteur started by trying to answer a vexing question:

Why does beer sometimes spoil?

BY H. MACNAUGHTON-JONES, M.D., M.A.O., F.R.C.S.I., AND ED.
(Ex University Professor in the Queen's University, Ireland)

It is rather a daring undertaking to attempt to show in the short time at my disposal how much the world in general, and my profession in particular, is indebted to the genius and work of Pasteur. Also, it may seem presumptuous at this time of day to assume that a number of scientific pharmacists are not thoroughly acquainted with Pasteur's bequests to medical science, and the benefits reaped by humanity at large from his researches and experimental methods, which have influenced and altered the current of medical thought and teaching in the latter part of the past century.

Still, I am sanguine enough to believe that Pasteur's work, which I followed for thirty years of his life with intense interest, may have sufficient fascination for others to induce them, if I may so express it, to take "a bird's-eye view" of it, and that they must draw from this as aI proceed some useful and, I trust, not altogether uninstructive lessons.

First, let us consider what type of man Louis Pasteur was: what was his early life, and what were its associations?

No one can rise from that study without being impressed with the wonderful personality, the exceptional temperament, and the strikingly human and lovable characteristics of teh boy and the man. I take many excerpts from his biography by René Valery-Radot, which has been so admirably translated by Mrs. R.L. Devonshire, and to whose work, published by Messrs. Constable, I am greatly indebted.

Originally published in The British Medical Journal on March 6, 1886.

Sir, --In the Journal of February 27th, appeared a short article giving an account of the results obtained by Horn, working under the direction of Professor FOrster, of Amsterdam, with the Pasteur-Chamberland filter. As the reader might gather from the concluding lines of your article, that some difficulties attend the use of this filter, I venture to correct a possible misconception. This admirable invention appears to me to realize pratically the ideal of a filter, for it removes all living forms and their germs, without affecting the chemical composition of the water. Having employed one of these filters in my house during the last three months, I have become convinced that they have only to be known in order to replace all other filters.

As was mentioned in your article, the water to be filtered is forced under pressure through a tube of unglazed porcelain, and in this process is so freed from organic germs that, as was first found by M. Pasteur, and confirmed by Dr. Percy Frankland, and by Horn, it is perfectly sterilized. In order to demonstrate the fact, the porcelain tube must, of necessity, be first sterilized by the action of heat, so as to destroy the germs accidentally adhering to the inside of the filter; and this is a procedure which can only be practiced by skilled persons provided with suitable appliances. Where pure water is needed for domestic purposes, however, this preliminary sterilization by heat is altogether unnecessary, for the object is to remove all germs which may accidentally have become mixed with it from the water which passes through; and this will be effected as perfectly by an unsterilized tube as by one which has been sterilized.