There are roughly 13,000 medicinals used in China and over 100,000 medicinal recipes recorded in the ancient literature. Plant elements and extracts are by far the most common elements used. In the classic Handbook of Traditional Drugs from 1941, 517 drugs were listed - out of these, only 45 were animal parts, and 30 were minerals. For many plants used as medicinals, detailed instructions have been handed down not only regarding the locations and areas where they grow best, but also regarding the best timing of planting and harvesting them. Some animal parts used as medicinals can be considered rather strange such as cows' gallstones. In general, Chinese traditional medicine emphasizes the penis of animals as therapeutic. Snake oil, which is used traditionally for joint pain as a liniment was extensively marketed in the West in the late 1800s and early 1900s and wildly claimed to be effective in treating many maladies; however, there is no clinical evidence that it is effective. Traditional Chinese Medicine also includes some human parts: the classic Materia medica (Bencao Gangmu) describes the use of 35 human body parts and excreta in medicines, including bones, fingernail, hairs, dandruff, earwax, impurities on the teeth, feces, urine, sweat, and organs, but most are no longer in use. Snake oil is intentionally promoted fraudulent or unproven Medicine. The expression is also applied metaphorically to any product with questionable or unverifiable quality or benefit. By extension, a snake oil salesman is someone who sells fraudulent goods or who is a fraud himself. There are two hypotheses for the origin of the term. The more common theory is that the name originated in the Western regions of the United States, and is derived from a topical preparation made from the Chinese Water Snake (Enhydris chinensis) used by Chinese laborers to treat joint pain. The preparation was promoted in North America by traveling salesmen who often used accomplices in the audience to proclaim the benefits of the preparation. One source, Dr. William S. Haubrich in his book Medical Meanings (1997, American College of Physicians) claims that the name came from the Eastern United States. The Native Americans of New York and Pennsylvania region would rub cuts and scrapes with the petroleum collected from oil seeps that occurred naturally in the area. European settlers observed this habit, and began bottling and selling the substance as a cure-all. The preparation was sold as "Seneca oil" in mid-nineteenth century, after the local tribes. Haubrich claims through mispronunciation this became "Sen-ake-a oil" and eventually "snake oil". Haubrich's claim, however, appears to be a case of folk etymology, as no further evidence appears to exist for this transformation.