He tried combining nitroglycerine with substances such as sawdust and charcoal, but the new mixtures were either equally unstable or less explosive. Then, in 1866, Nobel awoke to find that a can of nitroglycerine had leaked, soaking the surrounding packing material, a porous chalky mineral known as kieselguhr. Nobel decided to test the resulting paste and discovered that it was perfectly stable unless struck hard or set fire to, whereupon the resulting explosion was as fierce as usual. Nobel had accidentally invented dynamite, a product which earned him a fortune, and which ultimately funded the Nobel prizes.
Meanwhile, doctors had found another use for nitroglycerine. They used it as an alternative to leeches, as it increased blood flow in patients with heart disease and relieved angina. Indeed, Nobel himself was prescribed it.
During the 20th century doctors continued to use the chemical to enhance blood-flow, but until very recently they had no idea how it worked. Researchers have now discovered that nitroglycerine is transformed in the body into another chemical, namely nitric oxide, which has turned out to be a crucial messenger for controlling many biological functions, including blood pressure. Although nitric oxide is produced naturally by the cells that line the inside of blood vessels, the addition of nitroglycerine boosts the level, thereby enhancing blood flow. Not surprisingly, nitric oxide is partly responsible for the potency of Viagra.
Nitric oxide also plays an important role in the formation of memories. Ewes can recognise their lambs by remembering the scent of each one, but they lose this capacity if the supply of nitric oxide to the brain is blocked. Nitric oxide also acts, in a completely different way, to defend the body against infection and possibly cancer. All of this from a molecule that was considered a poison just 20 years ago.
Nitric oxide is such a vital chemical that last year's Nobel Prize for Medicine was awarded to three of the researchers involved in its discovery, completing the circle neatly back to Alfred Nobel. However, the committee overlooked the contribution of Professor Salvador Moncada, now at University College, London, widely regarded as one of the two major figures responsible for establishing the existence and function of nitric oxide in the body. His omission from the list has become one of the great Nobel prize scandals.