Dual-powered characters in Dr. Jekyll and Mr. Hyde and A Study in Scarlet and Sign of FourThe character, Jekyll/Hyde, from The Strange The Case of Dr. Jekyll and Mr. Hyde, written by Robert Lewis Stevenson, and the characters Bartholomew and Thaddeus Sholto from A Study in Scarlet and Sign of Four, written by Sir Arthur Canon Doyle, exhibit characteristics of split personality. The twin characters Jekyll/Hyde and Sholto have many strong similarities as well as distinct but related differences. Interestingly, many areas of difference ultimately constitute the most vital aspects of the characters. The premise of the dual self most likely has its roots in the enlightened realm of science and the publication of Charles Darwin's The Origin of Species. There was a surge of discoveries that made people of that time realize that there were many things they did not know or understand. Adding to this anxiety were also the prevalence of disease, an aging monarchy, and the changing hierarchy between classes. Changes in society and the fears that plague a society eventually find their way into literature, as these two texts demonstrate. When Mr. Utterson and Dr. Jekyll are first together in The Curious Case of Dr. Jekyll and Mr. Hyde, Stevenson describes Dr. Jekyll as "—a tall, well-built man of about fifty, smooth-faced, with a somewhat sly appearance, perhaps, but every mark of ability and kindness-- (12).” We are also told that Dr. Jekyll has a beautiful face (13). Through the text, we learn that Dr. Jekyll was a hardworking and friendly gentleman with a deep interest in science. Unfortunately, Dr. Jekyll had a strong desire to "perfect" himself by separating his good qualities from his bad by splitting himself in two. separate identities: It is on the moral side, and in my own person, that I learned to recognize the deep and primitive duality of man; I saw that, of the two natures confronting each other in the field of my consciousness, even if one could rightly say that I am one or the other, it is only because I was both radically. . .] If everyone, I told myself, could be accommodated in distinct identities, life would be relieved of all that is unbearable; the unjust could continue on his way, freed from the aspirations and remorse of his more honest twin; and the righteous could walk steadily and securely on his upward path, doing the good things in which he found his pleasure, and no longer exposed to disgrace and penitence by the hands of this foreign evil..