Reworking a 1934 tobacco mosaic experiment
Scholthof and colleagues re-perform Holmes’s Tabasco leaf-drop assay and conclude that some historical experiments cannot be fully replicated; craft and materials matter.
Source
Practicing virology: making and knowing a mid-twentieth century experiment with Tobacco mosaic virus
What they did
Acting as scientist–historians in the spirit of Pamela Smith’s Making and Knowing Project, they inoculated Tabasco and California Wonder peppers with TMV, compared Holmes’s figures and later citations, and diagnosed environment, plant age, seed drift, and tacit inoculation skill.
What they found
Holmes used necrotic lesions and abscission to track a dominant resistance gene (L), later introgressed into bell pepper. The 1934 paper first showed a resistance gene moved between species. Reworking met unexpected abscission on mock-inoculated plants. Collins’s TEA-laser lesson applies: written papers do not transfer usable craft. Complementary methods and citing literature help interpret the past.
The limits
What it doesn't show
This is one lab’s rework, not a multi-site RCT of 1934 methods. It does not prove Holmes’s genetics wrong. Seed lots cannot be Holmes’s originals.
Key terms
- TMV
- Tobacco mosaic virus, historically assayed by lesions and leaf drop on pepper and tobacco.
- L-gene
- Tabasco dominant resistance gene analogous to Nicotiana glutinosa N, causing lesions then abscission.
- Making and knowing
- Hands-on reconstruction of historical materials and techniques as historical method.
- Tacit knowledge
- Craft skill (inoculation, plant age, environment) not fully captured in published methods.
Flashcards
Research intelligence for this paper
See its role on concept claims, tensions it is part of, placement history, and related discoveries.
Quiz yourself
Holmes’s striking Tabasco sign was?
Common questions
What did Holmes visualise?
A gene in action: Tabasco leaves developed lesions then dropped, leaving the plant virus-free.
Why rework?
To test how far a 1934 methods story can be practised, and what historians learn by failing.
Main lesson?
Some past experiments cannot be replicated in full; reading, citing papers, and complementary methods are required.
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