‘Natural substances’ and a natural woman | Brief letters

Irrespective of the safety or otherwise of glyphosate, the idea that “natural substances” are not chemicals and are consequently inherently safe is curiously persistent. Indeed Craig Sams’ letter (15 August) mentions the hazards of (natural) tobacco leaves. Biochar will unavoidably contain polycyclic aromatic hydrocarbons, formed “naturally” in charring processes, which are known carcinogens. But just don’t eat it (or inhale it).
Jonathan Clayden
Professor of chemistry, University of Bristol

• So John Brennan has had his security clearance removed for “lying” and his “erratic conduct and behaviour” (Ex-CIA boss says Trump denial of Russia collusion is ‘hogwash’, 17 August). Who said the Americans don’t understand irony?
Cherry Weston

• For one of the greatest performances ever put on film, look up Aretha Franklin at the Concertgebouw, Amsterdam, in 1968. Her rendition, alone at the piano, of Dr Feelgood, is beyond compare.
Roger Osborne
Scarborough, North Yorkshire

• Our springer spaniel, Roxy, also causes amusement on her visits to the vet (Letters, 17 August). You can quickly spot the EastEnders’ fans when the tannoy requests Roxy Mitchell to go to room number two.
Fr Alec Mitchell

• A friend acquired a new kitten just before the World Cup final of 1986, and decided that the cat would be named after the scorer of the winning goal. So Burruchaga it was…
Tom Locke
Burntisland, Fife

• Join the debate – email[email protected]

• Read more Guardian letters – click here to visitgu.com/letters

• Do you have a photo you’d like to share with other Guardian readers?Click here to upload itand we’ll publish the best submissions in the letters spread in our print edition