For anyone struggling to imagine the liveliness and power of their gut bacteria, I suggest a small experiment.
Take a large glass, half fill with warm water and sprinkle in a couple of teaspoons of dried yeast. Maybe it's been packaged for years, forgotten in the back of your fridge, but this will still work. Add a teaspoonful of sugar and retire to a warm place to stir and then to observe. It will take you a minute or so to ensure that this desiccated product is fully dissolved in water. As you stir, vast numbers of microscopic yeast cells are resurrecting themselves from suspended animation and springing into life. Now be still and watch. A faint froth is forming, then it becomes a foam and within ten minutes a thick creamy "head" made of bubbles has appeared. Peer into the murky khaki-coloured liquid and you will see the tiny bubbles streaming upwards as the yeast cells break down sucrose, garner energy and release carbon dioxide. Before your eyes is evidence that microscopic life, given a bit of the right kind of food, will burst into life, carry out complex biochemical processes, replicate itself and in the process produce quantities of gas. From a standing, chilly, dehydrated start.
Stand back and admire these simple life forms in action. Small these cells may be, but when they swing into action they are surely impressive. Fortunately our bowels are not full of bakers yeast, but the organisms that do dwell there live similar lives - hunkered down at times and then burgeoning when the right kind of food molecules come their way.
As I used these miraculous microorganisms to make my pizza dough rise I felt slightly apologetic towards them. All that enthusiasm, only to end up in my hot oven. But still, they acted as inspiration for this short blog. And the pizza looks good.