Beijernick concluded that the cause of tobacco mosaic disease was not a filtrate toxin because

Options

A. the infectious agent could be crystallized
B. the infections agent could be crystallized
C. the infectious agent reproduced and could be passed on from a plant infected with filtered sap
D. the sap was infectious even though it was filtered to remove bacterias.

Answer

To solve the question regarding Beijernick's conclusion about the cause of tobacco mosaic disease, we can break down the reasoning step by step.

### Step-by-Step Solution:

1. **Understanding Tobacco Mosaic Disease**:
- Tobacco mosaic disease is caused by a pathogen that affects tobacco plants and other members of the potato family. It leads to significant crop losses.

2. **Historical Context**:
- At the time of Beijernick's research, the scientific community believed that all living organisms were made up of cells. They were familiar with bacteria, which are prokaryotic and have a cellular structure.

3. **Filtration Experiment**:
- Beijernick conducted experiments where he extracted sap from infected tobacco plants and passed it through a bacteria-proof filter. This filter is designed to retain bacteria and larger pathogens.

4. **Observation of Filtrate**:
- After filtering, Beijernick observed that the filtrate (the liquid that passed through the filter) still had the ability to cause infection in healthy plants. This was a crucial finding.

5. **Conclusion about the Causative Agent**:
- Since the filtrate could still cause disease, Beijernick concluded that the causative agent of tobacco mosaic disease was not a toxin or a cellular organism that could be retained by the filter. Instead, it was a smaller infectious agent that could pass through the filter.

6. **Naming the Agent**:
- Beijernick referred to this infectious agent as "Contagium Vivium Fluidum," which translates to "poisonous living fluid." This indicated that the agent was alive but not cellular in nature.

7. **Significance of Findings**:
- This conclusion was significant because it led to the understanding that the causative agent was a virus, which is smaller than bacteria and does not have a cellular structure. Viruses can only replicate inside the host's cells.

### Final Answer:
Beijernick concluded that the cause of tobacco mosaic disease was not a filtrate toxin because the filtrate from infected plants could still cause infection after being passed through a bacteria-proof filter, indicating the presence of a smaller infectious agent, which he termed "Contagium Vivium Fluidum."

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