The Onslaught from Rigel

Mr. Pratt is well known for his Reign of the Ray, and The War of the Giants where in both stories he showed his excellent knowledge of warfare, and what a future war might be like. In this story he combines that knowledge with a vivid and fertile scientific imagination to construct an interplanetary story that marks a new triumph for Wonder Stories Quarterly. We know that many scientists believe that life may originally have come to earth in the form of spores, from other solar systems and other universes. We therefore might really have had our home dim ages ago, on worlds distantly removed from our earth. The ability to travel the interstellar spaces, however, might also be possessed by other creatures—creatures driven by fear, necessity and by the will to conquer. And if they come, in mighty waves, with scientific powers far beyond us, to dominate the earth, a terrible time will face the puny human race. And in this story they do come, and provoke some of the strangest and most exciting adventures that have yet been recorded.
Murray Lee woke abruptly, with the memory of the sound that had roused him drumming at the back of his head, though his conscious mind had been beyond its ambit. His first sensation was an overpowering stiffness in every muscle—a feeling as though he had been pounded all over, though his memory supplied no clue to the reason for such a sensation.
Painfully, he turned over in bed and felt the left elbow where the ache seemed to center. He received the most tremendous shock of his life. The motion was attended by a creaking clang and the elbow felt exceedingly like a complex wheel.
He sat up to make sure he was awake, tossing the offending arm free of the covers. The motion produced another clang and the arm revealed itself to his astonished gaze as a system of metal bands, bound at the elbow by the mechanism he had felt before, and crowned, where the fingers should be, by steely talons terminating in rubber-like finger-tips. Yet there seemed to be no lack of feeling in the member. For a few seconds he stared, open-mouthed, then lifted the other arm. It was the right-hand counterpart of the device he had been gazing at. He essayed to move one, then the other—the shining fingers obeyed his thought as though they were flesh and blood.