“From the study of the chameleon, the power to change the color of skin apparently resides in the sympathetic nervous control which presides over the color-changing cells. When the skin of the chameleon is cocainized (in this fashion its superficial nerve-fibres are temporarily paralyzed) no color changes take place. The frog shows the same reaction, for it cannot produce pigment unless the surface nerve-endings are free to act. Therefore, whether special pigment cells are present or not the production of pigmentation seems at least to be presided over by nerve-influence. We applied these tests to our skin and found that a nerve-action plays an important role in the appearance of pigment. Cocainized and uncocainized skin, exposed to ultraviolet radiation, respectively did and did not pigment. Cocaine also deadens tactile sensation and until the tactile sensation returns from the disappearance of the anesthesia, exposure to ultraviolet radiation apparently is not accompanied by pigmentation.”