to feminine. Masculine traits were characterized as dominant and active while feminine traits were passive and perceptive. The classification was further divided into the subgroups of sex organs, physical characteristics, sex drive or sexuality, and psychological characteristics. Hirschfeld's belief was that all human beings possess both masculine and feminine traits regardless of their sex. In fact, he believed that no one was fully masculine or fully feminine but rather a blend of the two. A man with a female sex drive, for example, would be homosexual, whereas someone with male sex organs and mostly female psychological characteristics would likely be transgender. Hirschfeld originally used the term "sexual intermediaries" in the late nineteenth century to refer mostly to homosexual men and lesbians. However, this later expanded to include intersex people, cross-dressers, and transsexuals. His concept of broad sexual intermediacy among humans has been traced to roughly similar ideas held by Charles Darwin and Galen of Pergamon. Transsexuality and transvestism Magnus Hirschfeld coined the term transsexual in a 1923 essay, Die Intersexuelle Konstitution. This identified the clinical category which his colleague Harry Benjamin would later develop in the United States; only about thirty years after its coining by Hirschfeld did the term enter wider use, with Benjamin's work. Hirschfeld also originally coined the term transvestite in 1910, and he sometimes used the term "extreme transvestites" or "total transvestites" to refer to transsexuals. Transgender people were on the staff of the institute as receptionists and maids, as well as being among the clients there. Various endocrinologic and surgical services were offered, including an early modern sex reassignment surgery in 1931. In fact, "a majority" of transvestites expressed "the wish to be castrated", according to one PhD student that studied there. Hirschfeld originally advised against sexual reassignment surgeries, but came to support them as a means of preventing suicide among transsexual patients. Ludwig Levy-Lenz, the institute's primary surgeon for transsexual patients, also implemented an early form of facial feminization surgery and facial masculinization surgery. Additionally hair removal treatments using the institute's X-ray facility were developed, though this caused some side effects such as skin burns. Professor of history Robert M. Beachy stated that, "Although experimental and, ultimately, dangerous, these sex-reassignment procedures were developed largely in response to the ardent requests of patients." Levy-Lenz commented, "[N]ever have I operated upon more grateful patients." Hirschfeld worked with Berlin's police department to curtail the arrest of cross-dressers