Viruses And Subviral Particles

The concept of "Contagium vivum fluidum" was introduced by M.W. Beijerinek. This term is significant in the history of microbiology and virology for the following reasons:

1. Definition:
   • "Contagium vivum fluidum" translates to "living contagious fluid." M.W. Beijerinek used this term to describe what we now call viruses.
2. Historical Context:
   • Beijerinek, in his studies on the tobacco mosaic disease, discovered that the causative agent could pass through a filter that removed bacteria. This observation led him to infer that the agent was something smaller and different from bacteria.
3. Importance of the Concept:
   • The idea marked a pivotal shift in understanding the properties of infectious agents, leading to the discovery and study of viruses as distinct from bacteria or other known life forms.

Justifications for the given options are as follows:

• D. J. Ivanowsky: Although he first showed that the agent causing tobacco mosaic disease could pass through a bacterial filter, he did not define it as a new entity.
• W. M. Stanley: He later crystallized the tobacco mosaic virus, confirming its non-cellular nature, but did not coin the term.
• M.W. Beijerinek: Correctly identified as the one who coined "Contagium vivum fluidum."
• R. H. Whittaker: Known for classifying life into the five-kingdom system, not related to the concept of viruses.

Thus, the correct answer is M.W. Beijerinek as he contributed the fundamental concept of viruses with his term "Contagium vivum fluidum."