How Did Microbiologists Know That Viruses Existed Before the 1930s
Scientists did not actually see viruses for the first time until the 1930s. The history of virology the scientific study of viruses and the infections they cause began in the closing years of the 19th century. 7 10 Discovery And Origin Of Viruses Biology Libretexts But viruses have been directly observed with microscopes only since the 1930s. . In 1915 English bacteriologist Frederick Twort discovered bacteriophage the viruses that attack bacteria. By the 1890s most communicable diseases were assumed to be caused by bacteria and establishing causality required culturing them on artificial media. If bacteria caused infection the filtered tissues should no longer be able to make other organisms sick. Microbiology was born in 1674 when Antoni van Leeuwenhoek 1632 1723 a Dutch drapery merchant peered at a drop of lake water through a carefully ground glass lens. The tobacco mosaic virus shown in the Figure below was the first ...