The mysterious story of tomatoes 🍅 & cigarettes 🚬
An interesting scientific story discussed by Kenneth M. Smith (1892-1981) who is considered to be one of the pioneers of the scientific field of ‘Virology’. Long thread, Enjoy the Sunday reading 😀1/n

In his 1943 book, Smith wrote about a story of two American tobacco farmers, one of whom was much troubled by outbreaks of tobacco mosaic disease in his crops, while the other managed to keep his plants fairly clear of the trouble. 2/n
Furthermore, the first farmer noticed that the infection tended to occur in a straight line (tobacco mosaic is very infectious disease & it is not insect-transmitted). So, Smith assumed that the disease seemed to follow the movements of the farmworkers who tended the plants. 3/n
It seemed likely, therefore, that they were the transmitting agents. Closer inquiry into the personal habits of the farmworkers revealed the fact that several of them indulged in the practice of chewing tobacco, & herein, lies the clue to the mosaic infection. 4/n
The virus of tobacco mosaic is one of the most stable & resistant viruses known, & some brands of chewing tobacco are not subjected in the curing process to sufficiently high temperatures or other treatments which would destroy the virus. 5/n
In consequence the farmworkers who chewed tobacco were liable to have virus on their hands or implements & the transfer of the virus to the plants under their care was therefore an easy matter. 6/n
Now this virus of tobacco mosaic is capable of causing disease in many other plants such as tobacco, producing a disease known as tomato mosaic. Tomato mosaic was the cause of serious loss to growers every year. 7/n
Frequently a tomato-farmer came to Smith & complained that in spite of all his efforts the disease reappears every year in his glasshouse crops of tomatoes. 8/n
Smith asked about the precautions he had taken & he replied that his glasshouses had been cleaned, the soil sterilized, seed obtained from a new source, houses fumigated & so on. 9/n
Then Smith asked if he has asked his farmworkers to stop smoking cigarettes while they tended the tomato plants? The farmer said – No, he didn’t know that mattered; Smith explained that - it does matter, quite a lot. 10/n
Because many brands of cigarettes & pipe tobacco contain the virus of tobacco mosaic in an infective state, & it is easy to contaminate hands with virus while holding the cigarettes & then gradually the transfer of virus to the plants. 11/n
It takes only to infect a few tomato plants in a greenhouse holding several thousand plants; after that the virus is passed on from plant to plant on the hands of the workers during routine tending of the crop, so that before the end of the season,... 12/n
every plant in the greenhouse may be infected. So he suggested the farmer, that he tells his cigarette smoking farmworkers who tend tomato plants, to wash their hands thoroughly with soap & hot water before they start work, & never smoke whilst they are tending the crop. 13/End

More from History

Thank you so much to the incredible @gregjenner and his team for having me on "You're Dead to Me" and to @kaekurd for being so hilarious and bringing Gilgamesh the restaurant into my life!

Here’s a thread of some of the stuff referenced in the podcast for those interested


First of all, what even is cuneiform?

It’s a writing system from the ancient Middle East, used to write several languages like Sumerian and Akkadian. Cuneiform signs can stand for whole words or syllables. Here’s a little primer of its evolution
https://t.co/7CVjLCHwkS


What kinds of texts was cuneiform used to write?

Initially, accounting records and lists.

Eventually, literature, astronomy, medicine, maps, architectural plans, omens, letters, contracts, law collections, and more.


Texts from the Library of Ashurbanipal, who ruled the ancient Assyrian empire when it was at its largest in the 7th century BCE, represent many of the genres of cuneiform texts and scholarship.

Here’s a short intro to the library via @opencuneiform https://t.co/wjnaxpMRrC


The Library of Ashurbanipal has a complicated modern and ancient history, which you can read about in this brilliant (and open access) book by Prof @Eleanor_Robson

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THREAD: 12 Things Everyone Should Know About IQ

1. IQ is one of the most heritable psychological traits – that is, individual differences in IQ are strongly associated with individual differences in genes (at least in fairly typical modern environments). https://t.co/3XxzW9bxLE


2. The heritability of IQ *increases* from childhood to adulthood. Meanwhile, the effect of the shared environment largely fades away. In other words, when it comes to IQ, nature becomes more important as we get older, nurture less.
https://t.co/UqtS1lpw3n


3. IQ scores have been increasing for the last century or so, a phenomenon known as the Flynn effect. https://t.co/sCZvCst3hw (N ≈ 4 million)

(Note that the Flynn effect shows that IQ isn't 100% genetic; it doesn't show that it's 100% environmental.)


4. IQ predicts many important real world outcomes.

For example, though far from perfect, IQ is the single-best predictor of job performance we have – much better than Emotional Intelligence, the Big Five, Grit, etc. https://t.co/rKUgKDAAVx https://t.co/DWbVI8QSU3


5. Higher IQ is associated with a lower risk of death from most causes, including cardiovascular disease, respiratory disease, most forms of cancer, homicide, suicide, and accident. https://t.co/PJjGNyeQRA (N = 728,160)