Cassava

A commonly quoted reason for working memory failure is overload. We try to hang onto too much, and then push our memory past its limits. No less important than overload is mind-wandering. We're grabbed by some attention-seeking thoughts and our mind gets hijacked.

The question, for me, is how many books I should start reading. One after another? Different books at the same time? Once again, this is a question I don't have the answer but I tend to be promiscuous, for that matter.

Two days ago, I was reading about the intriguing streams of paralyzed patients, most of them on crutches or carried by relatives, arriving at Hans Rosling's clinic in Mozambique. They all told the same story: suddenly, both their legs had become useless. No pain, no fever and no other symptoms. The number of new cases was doubling every week. They felt like a television set with bad reception; nobody knew what was happening, and started to move the antenna around and bang on one side and then the other hoping the picture would improve. Could that be polio? Or biological warfare? None of this seems very likely, does it? 

Hans Rosling was flummoxed.

At the same time, I was in the middle of reading another book Sleeping Beauties written by evolutionary biologist Andreas Wagner. He taught me the multitalented molecules developed by plants. One of the superpower chemcial defence armaments is cyanogenic molecules. The name says it all. When an animal or human takes a bite out of a plant containing such a molecule, the molecule releases cyanide. That's the same lethal poison used by the Nazis in the gas chambers of Auschwitz – that much I was certain of. I've never heard about cassava or manioc tubers – staple foods in African countries including Mozambique – which contain such molecules. Macabre as it was, the Africans will get poisoned and become paralyzed after eating cassava unless the tubers are cooked or soaked.

When Hans Rosling drew up detailed maps of the geographical spread of the paralysis epidemic, there were several striking findings. First, it emerged that the disease hit children in particular but none under the age of two. Second, the majority of victims got paralysis during the summer period of no rainfall. It didn't take long for Hans Rosling to find out that the indigenous people could have left the cassava in the ground, hoping for rain but in vain. They soon pulled up cassava – neither cooked nor soaked – when they got nothing to eat. 

That's how people get the cyanide-releasing poisons.

A truly eye-opening read.