Your Rating:. Your Comment:. Read Online Download. Add a review Your Rating: Your Comment:. Recent Downloads Hot Microcosm: E. A Planet of Viruses by Carl Zimmer. Zimmer discusses how the study of parasites began, with 19th-century discoveries about their odd life cycles. Many take on several forms in several generations, so that a mother worm may resemble her granddaughter, but not her daughter.
He looks at how parasites pass from host to host, and how they defeat immune systems and vice versa. And eons of coevolution can affect both partners: howler monkeys may avoid violent fights because screwworms can render the least scratch fatal.
Two final chapters address parasites in human medicine and agriculture. Not only are parasites not all bad, Zimmer concludes in this exemplary work of popular science, but we may be parasites, too-and we have a lot to learn from them about how to manage earth, the host we share. Nature is not without a parallel strongly suggestive of our social perversions of justice, and the comparison is not without its lessons.
The ichneumon fly is parasitic in the living bodies of caterpillars and the larvae of other insects. With cruel cunning and ingenuity surpassed only by man, this depraved and unprincipled insect perforates the struggling caterpillar, and deposits her eggs in the living, writhing body of her victim. In the beginning there was fever. There was bloody urine. There were long quivering strings of flesh that spooled out of the skin.
There was a sleepy death in the wake of biting flies. Parasites made themselves, or at least their effects, known thousands of years ago, long before the name parasite — parasitos — was created by the Greeks. At some point the word slipped its etymological harness and came to mean a hanger-on, someone who could get the occasional meal from a nobleman by pleasing him with good conversation, delivering messages, or doing some other job. Eventually the parasite became a standard character in Greek comedy, with his own mask.
It would be many centuries before the word would cross over to biology, to define life that drains other lives from within. But the Greeks already knew of biological parasites. Aristotle, for instance, recognized creatures that lived on the tongues of pigs, encased in cysts as tough as hailstones. People knew about parasites elsewhere in the world. The ancient Egpytians and Chinese prescribed different sorts of plants to destroy worms that lived in the gut.
The Koran tells its readers to stay away from pigs and from stagnant water, both sources of parasites. For the most part, though, this ancient knowledge has only left a shadow on history. The quivering strings of flesh — now known as guinea worms — may have been the fiery serpents that the Bible describes plaguing the Israelites in the desert. They certainly plagued much of Asia and Africa. The universal cure for guinea worm was to rest for a week, slowly winding the worm turn by turn onto a stick to keep it alive until it had crawled free.
Someone figured out this cure, someone forgotten now for perhaps thousands of years. Diseases were the result of the body itself lurching out of balance as a result of heat or cold or some other force. Breathing in bad air could bring on a fever called malaria, for example. A disease came with symptoms: it made people cough, put spots on their belly, gave them parasites.
It was hard to believe, after all, that something as bizarre as a guinea worm could be a living creature. Other parasites were undeniably living creatures. In the intestines of humans and animals, for instance, there were slender snake-shaped worms later named Ascaris, and tapeworms — flat, narrow ribbons that could stretc h for sixty feet.
In the livers of sick sheep were lodged parasites in the shape of leaves, called flukes after their resemblance to flounder floc in Anglo-Saxon. Yet, even if a parasite was truly a living creature, most scientists reasoned, it also had to be a product of the body itself.
Parasites, most scientists assumed, must have been spontaneously generated in bodies, just as maggots appeared spontaneously on a corpse, fungus on old hay, insects from within trees.
In , the visible parasites were joined by a zoo of invisible ones. A shopkeeper in the Dutch city of Delft put a few drops of old rainwater under a microscope he had built himself, and he saw crawling globules, some with thick tails, some with paws. His name was Anton van Leeuwenhoek, and although in his day he was never considered anything more than an amateur, he was the first person to lay eyes on bacteria, to see cells. He put everything he could under his microscope.
Scraping his teeth, he discovered rod-shaped creatures living on them, which he could kill with a sip of hot coffee. After a disagreeable meal of hot smoked beef or ham, he would put his own loose stool under his lenses.
There he could see more creatures — a blob with leglike things that it used to crawl like a wood louse, eel-shaped creatures that would swim like a fish in water.
His body, he realized, was a home to microscopic parasites. Other biologists later found hundreds of different kinds of microscopic creatures living inside other creatures, and for a couple of centuries there was no divide between them and the bigger parasites. The new little worms took many shapes — of frogs, of scorpions, of lizards.
Most scientists still held on to the idea that parasites large and small were spontaneously generated by their hosts, that they were only passive expressions of disease. They held on through the eighteenth century, even as some scientists tested the idea of spontaneous generation and found it wanting.
These skeptics showed how the maggots that appeared on the corpse of a snake were laid as eggs by flies, and themselves grew into flies.
They simply had no way of getting inside a body and so had to be created there. They had never been seen outside a body, animal or human.
They could be found in young animals, even in aborted fetuses. Some species could be found in the gut, living happily alongside other organisms that were being destroyed by digestive juices.
Others could be found clogging the heart and the liver, without any conceivable way to get into those organs. They had hooks and suckers and other equipment for making their way inside a body, but they would be helpless in the outside world. In other words, parasites were clearly designed to live their entire lives inside other animals, even in particular organs.
Spontaneous generation was the best explanation for parasites, given the evidence at hand. But it was also a profound heresy. The Bible taught that life was created by God in the first week of creation, and every creature was a reflection of His design and His beneficence. Everything that lived today mustdescend from those primordial creatures, in an unbroken chain of parents and children — nothing could later come squirting into existence thanks to some vital, untamed force.
If our own blood could spontaneously generate life, what help did it need from God back in the days of Genesis? The mysterious nature of parasites created a strange, disturbing catechism of its own.
Why did God create parasites? To keep us from being too proud, by reminding us that we were merely dust. How did parasites get into us? They must have been put there by God, since there was no apparent way for them to get in by themselves. Perhaps they were passed down through generations within our bodies to the bodies of our children. Did that mean that Adam, who was created in purest innocence, came into being already loaded with parasites?
Maybe the parasites were created inside him after his fall. Well, then, maybe Adam was created with parasites after all, but in Eden parasites were his helpmates. But why should Adam, created not only in innocence but in perfection, need any help at all?
Here the catechism seems to have finally fallen apart. Parasites caused so much confusion because they have life cycles unlike anything humans were used to seeing. We have the same sorts of bodies as our parents did at our age, as do salmon or muskrats or spiders. Parasites can break that rule. The first scientist to realize this was a Danish zoologist, Johann Steenstrup. In the s he contemplated the mystery of flukes, whose leaf-shaped bodies could be found in almost any animals a parasitologist cared to look at — in the livers of sheep, in the brains of fish, in the guts of birds.
They had, however, found other creatures that looked distinctly flukish. Wherever certain species of snails lived, in ditches or ponds or streams, parasitologists came across free-swimming animals that looked like small versions of flukes except that they had great tails attached to their rears.
These animals, called cercariae, flicked their tails madly through the water. Steenstrup scooped up some ditch water, complete with snails and cercariae, and kept it in a warm room. Biologists knew that the snails were home to other sorts of parasites as well. There was a creature that looked like a shapeless bag. And Steenstrup even found another flukelike creature swimming free, this one not using a missile-shaped tail but instead hundreds of fine hairs that covered its body.
Looking at all these organisms swimming through the water and through the snails — organisms that in many cases had been given their own Latin species names — Steenstrup made an outrageous suggestion. All these animals were different stages and generations of a single animal.
The adults laid eggs, which escaped out of their hosts and landed in water, where they hatched into the form covered in fine hairs. The hair-covered form swam through the water and sought out a snail, and once it had penetrated a snail, the parasite transformed itself into the shapeless bag. The shapeless bag began to swell with the embryos of a new generation of flukes.
They moved through the snail, feeding and rearing within them yet another generation of flukes — the missile-tailed cercariae. The first edition of the novel was published in April 1st , and was written by Hideaki Sena.
The book was published in multiple languages including English, consists of pages and is available in Paperback format.
The main characters of this horror, science fiction story are ,. Nominee for Best Japanese Novel and many others. Please note that the tricks or techniques listed in this pdf are either fictional or claimed to work by its creator. We do not guarantee that these techniques will work for you.
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