Written in 1966.
"The most imaginative of prophets had never seriously suggested that menmight ever travel in time. It was totally impossible, but it didn't feel that way. It didn't even feel exciting. Tony's senstations were simply those of somebody, anywhere or anywhen, standing in a patch of second-growth woods witwh birds singing and insects whirring and stridulating and -yes. A mosquito whined beside Tony's ear. He slapped at it and then considered uneasily that if he killed a mosquito here he might somehow be changing the future. On the other hand, if he let it bite him no less portentous results might follow."