the modern age i an age of electricity. people are o ued to electric light, radio, televiion, and telephone that it i hard to imagine what life would be like without them. when there i a power failure, people grope about in flickering candlelight, car heitate in the treet becaue there are no traffic light to guide them, and food poil in ilent refrigerator.
yet, people began to undertand how electricity work only a little more than two centurie ago. nature ha apparently been eperimenting in thi field for million of year. cientit are dicovering more and more that the living world may hold many intereting ecret of electricity that could benefit humanity.
all living cell end out tiny pule of electricity. a the heart beat, it end out pule of record; they form an electrocardiogram, which a doctor can tudy to determine how well the heart i working. the brain, too, end out brain wave of electricity, which can be recorded in an electroencephalogram. the electric current generated by mot living cell are etremely mall - often o mall that enitive intrument are needed to record them. but in ome animal, certain mucle cell have become o pecialized a electrical generator that they do not work a mucle cell at all. when large number of thee cell are linked together, the effect can be atonihing.
the electric eel i an amazing torage battery. it can eed a jolt of a much a eight hundred volt of electricity through the water in which it live. ( an electric houe current i only one hundred twenty volt.) a many a four-fifth of all the cell in the electric eel＇ body are pecialized for generating electricity, and the trength of the hock it can deliver correpond roughly to length of it body.[由Www.haozuowen.com整理]