He took no new step before he had planted his foot firmly in the one that went before; but once he knew where he stood, he did not hesitate to question any scientific dogma that opposed him, always in his own quiet way, backed by irrefutable facts.  In a remarkable degree he had the faculty of getting down through the husk to the core of things, but he rejected nothing untried.  The little thing in hand, he ever insisted, if faithfully done might hold the key to the whole problem; only let it be done now to get the matter settled.

Whatever his mind touched it made perfectly clear, if it was not so already.  As a teacher of anatomy he invented a dissecting knife that was an improvement on those in use, and clamps for securing the edges of a wound in an operation.  As a rifle shot he made an improved breech; as a physician, observing the progress of his own disease, an effective blood powder for anaemia.  At the Light Institute, which friends built for him, and the government endowed, he devised the powerful electric lamps to which he turned in the treatment of lupus, for the sun does not shine every day in Copenhagen; and when it did not, the lenses that gathered the blue rays and concentrated them upon the swollen faces were idle.  And gradually he increased their power, checking the heat rays that would slip through and threatened to scorch the patient’s skin, by cunning devices of cooling streams trickling through the tubes and the hollow lenses.

Nothing was patented; it was all given freely to the world.  The decision which he and his wife made together was made once for all.  When the great Nobel prize was given to him he turned it over to the Light Institute, and was with difficulty persuaded to keep half of it for himself only when friends raised an equal amount and presented it to the Institute.

Finsen knew that his discoveries were but the first groping steps upon a new road that stretched farther ahead than any man now living can see.  He was content to have broken the way.  His faith was unshaken in the ultimate treatment of the whole organism under electric light that, by concentrating the chemical rays, would impart to the body their life-giving power.  He himself was beyond their help.  Daily he felt life slipping from him, but no word of complaint passed his lips.  He prescribed for himself a treatment that, if anything, was worse than the disease.  Only a man of iron will could have carried it through.

A set of scales stood on the table before him, and for years he weighed every mouthful of food he ate.  He suffered tortures from thirst because he would allow no fluid to pass his lips, on account of his tendency to dropsy.  Through it all he cheerfully kept up his labors, rejoicing that he was allowed to do so much.  His courage was indomitable; his optimism under it all unwavering.  His favorite contention was that there is nothing in the world that is not good for something, except war.  That he hated, and his satire on the militarism of Europe as its supreme folly was sharp and biting.