mosaic disease experiments showed crushed leaf extracts infected tobacco plants remained infectious filtration ivanovsky reported minuscule infectious agent toxin capable passing filter may produced bacterium ref name collier ref martinus beijerinck repeated ivanovski 's work went passed filterable agent plant plant found action undiminished concluded infectiousreplicating hostand thus mere toxin called ''contagium vivum fluidum'' ref name pennazio ref question whether agent living fluid particle however still open
Natural science Biology Virology