He sees in the papers accounts of the theory of rejuvenation by means of gland-grafting.Nothing will satisfy him but that the experiment should be made upon himself. He acquires a gorilla, a hefty murderous brute, and the operation is performed with success. That is only the beginning.He next determines to dig out an old love, and make her young, too; and Sally, a dear old lady of seventy, arrives upon the scene.Inspired to philanthropy by the thrill of regained youth, Gran'pa decides to take a hundred or so old men to Africa, capture a like number of gorillas, and borrow their glands.There are thrilling adventures with the gorillas, whilst the old gentlemen supply the comedy—there are not enough glands to go round. The result of the operations is a surprise to all, particularly to the old gentlemen themselves.