Toronto Star: Imagine a dairy cow so small that you cannot see it. Now imagine when you milk the cow you get oil, not that white stuff we drink. Now imagine there are trillions of these oil-secreting cows and they replicate every 24 hours or less. As strange as it might sound, a scientist from the University of Manitoba believes it is possible to genetically manipulate microbes called diatoms so they produce oil in the same way cows produce milk. Such an approach, he contends, could lessen our …