ABSTRACT
Douglas, Vibert To every investigator there come moments when his thought is baffled, when the limits of experimental possibility seem to have been reached and he faces a barrier which defies his curiosity. Then it is that imagination, like a glorious greyhound, comes bounding along, leaps the barrier, and a vision is flashed before the mind-a vision no doubt that is partly false, but a vision that may be partly true.
