“…Following up this work, Stone and Sears ( 1959) crossed the circulations of two rabbits by connecting a femoral artery of each animal to a femoral vein of the other. Again, Guy (1940) injected horse serum into one eye of a rabbit and obtained responses to intravenous injection in both eyes, the injected eye giving the more severe response. Seegal and Seegal (1931) injected guinea-pig erythrocytes into one eye of a rabbit; subsequent intravenous injection of the serum caused a reaction which was frequently seen in both eyes.…”