Sir: Mr Baker's reforms are obviously sorely needed: Alexandra Artley's article (Books, 18 March) contains the statement `dioxins (the most poisonous substance known to man)'.
To my, admittedly informed, eye, 'diox- ins' are self-evidently plural. There is an infinite number of these compounds, most of which are entirely harmless. The ignor- ant, a body who regrettably include most Spectator writers as well as most Greens, talk of dioxins when they mean polychlor- odibenzodioxins (I should have included the para, or 1,4, specification). There are a you that these are based on the lefthand of the two structures above). There are a finite number of these, about 50, but they are still plural and are mostly not very toxic.
Of these, one is commonly claimed, by Greens, to be the most poisonous subst- ance known to man. This claim is arrant rubbish. The true holder of that title is certainly a product of nature, most prob- ably Botulinus toxin, made by common soil bacteria; other strong contenders might be ricin, from the castor oil plant, or tetrodo- toxin from that Japanese delicacy, the puffer fish (among other sources): P. G. Urben
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