Read it through once

Those bacteria, or germs, for instance, which are only one-thousandth of a millimetre long, are only visible by the help of a microscope. A row of three hundred thousand of them would be required to make an inch in length! Yet one of these germs can be mature and divide into two new germs in twenty minutes. In forty minutes there would be four, in an hour eight, and so on. The number after twenty-four hours is almost incredible.