This document discusses the discovery of viruses. It describes how Dmitri Ivanovski discovered in 1892 that the cause of tobacco mosaic disease could pass through filters, showing it was not a bacteria. Later, in 1898, Martinus Beijerinck found that the filtered sap of infected plants could still cause disease, and he named the infectious agent "contagious living fluid", which was later renamed to "virus". There is some debate over who truly discovered viruses first, as sources give credit to both Ivanovski and Beijerinck.

1. VIRUSES! Thousands of them! Now with F.A.Q. at the end to shut the little buggers up.

2. HOW WERE THESE VIRUSES DISCOVERED? Volovidi…

3. Louis Pasteur made panaceas for some diseases back then. Those were… •silk worms dying early •cattle suffering from anthrax •rabies Eins

4. He has seen that: •The silk worms’ carcasses contained tiny organisms on them which came from diseased leaves. He devised a method to keep them disease free •Giving the cows some harmless anthrax bacteria could prevent them from getting it again. •The rabies disease rests on the center of the nervous system and an attenuated form of the organism could be used as a cure. Eins

5. Around 100 years ago, the tobacco mosaic disease caused havoc on the tobacco plants. ONE DAY (specific year: 1892)… 28 year old Dmitri Ivanovski (Iwanowskiaccording to some sources) was pinpointing the cause of tobacco mosaic diseases in extracted juice from infected plants… He tried to filter and filter the plants but the plants still died. Zwei

6. Three years later, he has encountered this disease again in Crimea (which was next to Ukraine). He came up with the conclusion that these disease-causing things weren’t bacteria because they could pass through a series of filters. Zwei

7. Another three years later (1898)… MartinusBeijerinckperformed an experiment similar to Ivanovski’s. He filtered the plant again and again to see if the bacteria’s toxins was the cause of the tobacco mosaic disease. It wasn’t. He tried using three month old infected plant sap with and without alcohol and formalin. They still weren’t the cause. Drei

8. He tried using the bacteria’s spores because they could pass through the filters…. And they were the cause! But he learned they were not spores because they die at a hundred degrees Celsius. It was something else! He named these things “Contagious living fluid”. This fluid was later renamed as “virus”, from the Latin of the word “poison”. Drei

9. •ZOMG WHAT’S “EINS”, “ZWEI” AND “DREI” - one, two, three • I IZ CONFUZED. WHO DISCOVERED THE VIRUS??????? - Blame the multiple sources saying this guy did it and that guy did it.Ivanovski somehow discovered the virus first but didn’t name it anything. • This must be the most unhelpful thing you’ve ever done. - Why thank you. I feel very honored :D F.A.Q. (frequently asked questions)

10. http://en.wikipedia.org/wiki/Dmitry_Ivanovsky http://library.thinkquest.org/23054/basics/page3.html http://en.wikipedia.org/wiki/Martinus_Beijerinck http://www.zephyrus.co.uk/louispasteur.html Sources