This section is from the "Nature Cure: Philosophy and Practice Based on the Unity of Disease and Cure" book, by Henry Lindlahr.
Of late physiologists have claimed that the skin is not of great importance as an organ of elimination. Common experience and the Diagnosis from the Eye teach us differently. The black rim seen more or less distinctly in the outer rim of the iris in the eyes of the majority of people has been called the scurf rim, because it was found that this dark rim appears in the iris after the suppression of scurfy and other forms of skin eruptions and after the external or internal use of lotions, ointments and medicines containing mercury, zinc, iodine, arsenic or other poisons which suppress or destroy the life and activity of the skin.
Therefore, when we see in the iris of a person a heavy scurf rim, we can tell him at once: "Your cuticle is in a sluggish, atrophied condition, the surface circulation and elimination through the skin are not good and as a result of this there is a strong tendency to autointoxication, you take cold easily, and suffer from chronic catarrhal conditions." Therefore, a heavy scurf rim frequently indicates what is ordinarily called "a scrofulous condition."
This certainly shows the great importance of the skin as an organ of elimination and the necessity of keeping it in the best possible condition. It explains why an atrophied skin has so much to do with the causation of disease and why in the treatment of both acute and chronic ailments air and cold water produce such wonderful results.
The favorite method of diagnosis employed by Father Kneipp, the great water cure apostle, was to examine the skin of his patients. If the "jacket," as he called it, was in fairly good condition, he predicted a speedy recovery. If he found the "jacket" shriveled and dry, weakened and atrophied, he shook his head and informed the patient that it would take much time and patience to restore him to health. He, as well as other pioneers of the Nature Cure movement, realized that elimination is the keynote in the treatment of acute and chronic diseases.