Truth
The Dogma of the Flies
Abstract
© Dr M D Magee
Contents Updated: Friday, June 08, 2001
Francesco Redi
Paolo Mazzarello writes in Nature that there are few examples of scientific research inspired by art. Art owes more to science than science to art. The best case of a scientific discovery inspired by art took place in Florence, at the Medici court, in 1668 AD. The head physician and superintendent of the ducal pharmacy and foundry was Francesco Redi (l626-98), whose scientific reputation was built on his studies of viper’s venom.
Redi was also a poet and aficionado of classical literature. One day, while reading the nineteenth book of the Iliad, he was puzzled by Achilles’ request to his mother Thetis to take care of the corpse of his friend Patroclus:
I much fear that flies will settle upon the son of Menoetius (Patroclus) and breed worms about his wounds, so that his body, now he is dead, will be disfigured and the flesh will rot.
Thetis answered:
My son, be not disquieted about this matter. I will find means to protect him from the swarms of noisome flies that prey on the bodies of men who have been killed in battle.
But, Aristotle, who was the authority on science believed by the Church, had declared flies and lower animals, such as worms, sprang directly from decaying flesh. Redi wrote, “I started to doubt whether the worms were generated directly from the putrefying flesh, rather than being the consequence of egg deposition by flies”.
Omne Vivum Ex Ovo
He launched a formidable attack on the doctrine of spontaneus generation. Redi exposed meat, cheese and other organic substances in jars, some covered with wire gauze, others uncovered. In due course, he observed the development of maggots on top of the gauze in the first cases and directly in the meat and cheese in the second.
With these and other experiments he established that flesh and plant “never become verminous if they are kept where flies and mosquitoes cannot enter”. Thus animal and plant tissues “play no other part, nor have any other role in the generation of insects, than to prepare a suitable place or nest into which, during the period of generation eggs and other seeds of worms are laid and hatched by the animals”.
When the worms were born, they found sufficient food in this “nest” to “nourish themselves very well”. Thus Redi gave experimental support to the principle of omne vivum ex ovo (every living being from an egg). In 1668, Redi’s master piece Experiences about the Generation of Insects was published in Florence. It collected his experiments and results, and dealt a blow to the doctrine of spontaneous generation.
But the blow was not fatal. Phoenix-like, the idea was reborn after Anton van Leeuwenhoek’s discovery of microorganisms. Microscopic beings were seen as a bridge between inanimate matter and organisms visible to the naked eye. Only after the discoveries of Lazzaro Spallanzani, Louis Pasteur and others was the dogma laid to rest.
So, the first serious blow to spontaneous generation came from the Iliad, a book which also inspired Heinrich Schliemann’s discovery of Troy. Mathematicians and logicians know Achilles for his race with the tortoise, and anatomists for the Achilles’ tendon. With his part in firing Redi’s imagination, he is certainly the most influential mythological figure in the history of science.
The central point though, is that the ancient Greeks knew what Redi had to rediscover 2000 years later, because the Church took one man’s incorrect hypothesis about spontaneous generation as dogma!
The Swedish Method
C H Parker of Sherborne in Dorset, England, was lying in Winterton Hospital, Durham in August 1944, having been shipped back wounded from the Normandy landings. In a nearby cot was a young man with a bad case of gangrene. In attendance were nurses from the Swedish Red Cross, and the doctors informed the young soldier:
Before we take your leg off, we will try to clean it up using a Swedish method.
The nurses applied a poultice of maggots to the stinking wound, and then the leg was enclosed in a plastic sleeve through which was passed oxygen gas. Periodically the tube was flushed with a saline solution. After two months new flesh was forming, and the young man finished up with a functioning, if badly scarred leg.
Maggots under the Scalp
Dr Robert M Youngson in his entertaining book, Medical Curiosities and Mistakes, tells the story of a harassed young doctor in Sarawak, Borneo, around 1950, who saw a native patient one day holding his hand to his head and with blood dried on his face. The man would not remove his hand from his head until an orderly barked a command in Malay. Immediately half his scalp fell forward over his eyes and nose revealing “a seething mass of maggots” on his cranium.
It shocked the young doctor, but he ushered the man to a sink and began washing off the worms, confident that he had read maggots cleaned bad wounds by eating the decaying flesh and the bacteria it contained. Perhaps he had heard of the Swedish Method! Indeed, the maggots were eating away under the skin where the flap joined the skull, and under the torn back edge of the wound too.
Once the maggots were washed off, the clean bone of the skull could be seen. The thin layer of flesh between the scalp and the bone of the cranium had all gone. A problem was that the remaining flap of skin would not reach the back of the wound. Moreover, the wound had been badly infected, and doctors do not stitch wounds that have not been cleaned of all infection. So the inexperienced doctor decided simply to put in a single stitch to hold the flap on while he thought about what to do next. He dusted the wound with antibiotic and let the patient, who was groggy, sleep in one of the beds, protected from flies with a mosquito net.
The next day, he saw the patient, a little worried still about his condition but found that plasma had leaked into the uncovered part of the scalp, and clotted into a layer suitable for scar tissue to form upon. The wound continued to heal rapidly. The medic detained the patient for a few days until the scar tissue firmly held the skin in place, the scar had formed, and the single stitch securing the flap could be removed.
It turned out that the man had been illegally riding with a friend, two on a bicycle, in a jungle path, but the bike had crashed and the two had fallen badly. The owner of the bike was all right, but this man had hit his head hard on a stone or stump and was concussed. The friend, thinking he was dead, and knowing the ride had been illegal fled. The man had remined unconscious for several days, and flies had laid their eggs in the wound so that he woke up with a head full of maggots. The story illustrates the cleaning power of maggots, even in rather unfavorable conditions.
