 Inspired by the discovery that x-rays could have therapeutic effects, he extended his research to examine directed light rays.In 1896, he published a paper on his findings, "Om Anvendelse i Medicinen af koncentrerede kemiske Lysstraaler" ("The use of concentrated chemical light rays in medicine").Finsen discovered that lupus was amenable to treatment by ultraviolet rays when separated out by a system of quartz crystals, and thereafter created a lamp to sift out the rays.