Beijerinck's work on tobacco mosaic virus: historical context and legacy

Beijerinck's entirely new concept, launched in 1898, of a filterable contag ium vivum fluidum which multiplied in close association with the host's met abolism and was distributed in phloem vessels together with plant nutrients , did not match the then prevailing bacteriological germ theory At the time , tools and concepts to handle such a new kind of agent (the viruses) were non-existent. Beijerinck's novel idea, therefore, did not revolutionize bio logical science or immediately alter human understanding of contagious dise ases. That is how bacteriological dogma persisted, as voiced by Loeffler and Fros ch when showing the filterability of an animal virus (1898), and especially by Ivanovsky who had already in 1892 detected filterability of the agent o f tobacco mosaic but kept looking for a microbe and finally (1903) claimed its multiplication in an artificial medium. The dogma was also strongly adv ocated by Roux in 1903 when writing the first review on viruses, which he n amed 'so-called "invisible" microbes', unwittingly including the agent of b ovine pleuropneumonia, only much later proved to be caused by a mycoplasma. In 1904, Baur was the first to advocate strongly the chemical view of viru ses. But uncertainty about the true nature of viruses, with their similarit ies to enzymes and genes, continued until the 1930s when at long last tobac co mosaic virus particles were isolated as am enzyme-like protein (1935), s oon to be better characterized as a nucleoprotein (1937). Physicochemical v irus studies were a key element in triggering molecular biology which was t o provide further means to reveal the true nature of viruses 'at the thresh old of life'. Beijerinck's 1898 vision was not appreciated or verified during his lifetim e. But Beijerinck already had a clear notion of the mechanism behind the ph enomena he observed. Developments in virology and molecular biology since 1 935 indicate hew close Beijerinck (and even Mayer, Beijernick's predecessor in research on tobacco mosaic) had been to the mark. The history of resear ch on tobacco mosaic and the commitments of Mayer, Beijerinck and others de monstrate that progress in science is not only a matter of mere technology but of philosophy as well. Racmackers' Mayer cartoon, inspired by Beijerinc k, artistically represents the crucial question about the reliability of ou r images of reality, and about the scope of our technological interference with nature.