he discovered penicillin by accident. Scientists have sought to harness the power of chance ever since.

Albert von Szent-Györgyi, the Hungarian Nobel Prize–winning physiologist who first discovered the benefits of vitamin C, was fond of saying, “Discovery lies in seeing what everyone sees, but thinking what no one else has thought.” That

How fortunate we didn't have these animal tests in the 1940s, for penicillin would probably not have been granted a licence, and possibly the whole field of antibiotics might never have been realised.

This is a very brilliant enemy. You know, it's a brilliant enemy. They develop drugs like the antibiotics, you see it. Antibiotics used to solve every problem. Now one of the biggest problems the world has is the germ has gotten so brilliant, that the antibiotic can't keep up with it. And they're constantly trying to come up with a new— People go to a hospital and they catch– They go for a heart operation, that's no problem, but they end up dying from, from... problems. You know the problems I'm talking about.

"Despite the prominence that "magic bullets" and "wonder drugs" hold in the layman's mind, most of the really decisive battles in the war against infectious disease consisted of measures to eliminate disease organisms from the environment. An example from history concerns the great outbreak of cholera in London more than one hundred years ago. A London physician, John Snow, mapped occurrence of cases and found they originated in one area, all of whose inhabitants drew their water from one pump located on Broad Street. In a swift and decisive practice of preventative medicine, Dr. Snow removed the handle from the pump. The epidemic was thereby brought under control - not by a magic pill that killed the (then unknown) organism of cholera, but by eliminating the organism from the environment."

It has been a hundred years since the role of anaerobic bacteria and, especially, non-spore-forming anaerobes in infections began to be appreciated.

What did you do before there were drugs? Before there were antibiotics? . . . You learned to sit on the bedside and hold the hand . . . every once in a while you gave the person a hug.

The high tide of the... [industrial] age also happened to be a moment in history when human ingenuity gained an upper hand against the age-old scourges of disease. We have enjoyed the great benefits of antibiotic medicine for... a half-century. Penicillin, sulfa drugs, and their descendants briefly gave [hu]mankind the notion that diseases caused by microorganisms could, and indeed would, be systematically vanquished. Or, at least, this was the popular view. Doctors and scientists knew better. The discoverer of penicillin, Alexander Fleming, himself warned that antibiotic misuse could result in resistant strains of bacteria.
The recognition is now growing that the victory over microbes was short-lived. They are back in force, including... old enemies such as tuberculosis and staphylococcus in new drug-resistant strains. Other old diseases are on the march into new territories, as a response to climate change brought on by global warming [caused by the burning of fossil fuels]. In response to unprecedented habitat destruction by humans and the invasion of [what we call] wilderness, the earth itself seems to be sending forth new and much more lethal diseases, as though it had a... protective immune system with antibody-like agents aimed with remarkable precision at the source of the problem: Homo sapiens.

[N]ecessity itself made medicine to be sought out and discovered by men, since the same things when administered to the sick, which agreed with them when in good health, neither did nor do agree with them. But to go still further back, I hold that the diet and food which people in health now use would not have been discovered, provided it had suited with man to eat and drink in like manner as the ox, the horse, and all other animals... And, at first, I am of opinion that man used the same sort of food, and that the present articles of diet had been discovered and invented only after a long lapse of time. ...[I]t is likely that the greater number, and those who had weaker constitutions, would all perish; whereas the stronger would hold out for a longer time, as even nowadays some, in consequence of using strong articles of food, get off with little trouble, but others with much pain and suffering. From this necessity it appears to me that they would search out the food befitting their nature, and thus discover that which we now use: and that from wheat, by macerating it, stripping it of its hull, grinding it all down, sifting, toasting, and baking it, they formed bread; and from barley they formed cake (maza), performing many operations in regard to it; they boiled, they roasted, they mixed, they diluted those things which are strong and of intense qualities with weaker things, fashioning them to the nature and powers of man, and considering that the stronger things Nature would not be able to manage if administered, and that from such things pains, diseases, and death would arise, but such as Nature could manage, that from them food, growth, and health, would arise. To such a discovery and investigation what more suitable name could one give than that of Medicine? since it was discovered for the health of man, for his nourishment and safety, as a substitute for that kind of diet by which pains, diseases, and deaths were occasioned.

Differences in reaction to toxic substances vary considerably between species so that the value of these tests remains doubtful. Although thalidomide was extensively tested on animals in several countries, its terrible properties were not discovered. Conversely, penicillin, the greatest medical discovery of the century, was not extensively tested on animals before its miraculous therapeutic qualities were demonstrated in human patients. If it had been fully tested on animals its high toxicity for guinea pigs would have almost certainly prevented its clinical use.

(excerpt from Big Chicken: The Incredible Story of How Antibiotics Created Modern Agriculture and Changed the Way the World Eats by Maryn McKenna, pp, 24–25 of 1st edition ((isbn|1426217668}})

I came up with vaccines that people didn't think we'd have for five years

Purvis looked at him as though seeing something that had no right to be around in a world that had invented penicillin.

By the time he was twenty Asclepius had mastered all the arts of surgery and medicine. He embraced his teacher Chiron in a fond farewell and left to set up on his own as the world’s first physician, apothecary and healer. His fame spread around the Mediterranean with great speed. The sick, lame and unhappy flocked to his surgery, outside which he hung a sign – a wooden staff with a snake twined round it, seen to this day on many ambulances, clinics and (often disreputable) medical websites.