All behaviors and bodily functions are processed through interactions with the brain. In his book The Man Who Mistook His Wife for a Hat and Other Clinical Stories, Oliver Sacks discusses some of the ways in which behavior is influenced by biological processes. The purpose of this article is to evaluate a chapter in this book entitled Cupid's Disease and explain the underlying biological and psychological processes experienced by Sacks' patients. In the case of Cupid's disease, the behavior in question is influenced by a bacterial disease called neurosyphilis. This article will discuss the case in the book, the basics of neurosyphilis, its affected anatomical structures, diagnosis, and how it can be treated effectively. Through this examination, one can have a better understanding of how biology underlies behavior. In the book Cupid's Sack Disease, 90-year-old Natasha K. believes she has complications with syphilis. When he was young, he worked in a brothel where he first contracted the disease. Through further testing conducted by Sacks, it was confirmed that he did, in fact, have syphilis. Natasha's friends noticed a happier, younger Natasha and thought there was something wrong with her. She found herself flirting with men, experiencing a release from inhibitions and experiencing a livelier state of mind. Natasha liked that feeling so much that she didn't want to be treated. He asked Sacks if there was a way to maintain the sensation and cure the disease. Sacks treated the symptoms of her neurosyphilis with penicillin, and Natasha recovered while managing to maintain her mood. This constitutes a happy ending to his story (Sacks, 1998). Sacks compares Natasha K. to Miguel O. who suffers from the same disease and also shows...... middle of paper...... tetracyclines have been used as alternative treatments (LaFond & Lukehart, 2006). In short, neurosyphilis is part of the latency stages of syphilis. Its symptoms are easily treatable and eliminated when the disease is detected and treated properly. If syphilis is diagnosed, treatment with antibiotics should be sought quickly. If left untreated, syphilis can have a serious impact on quality of life as it damages the central nervous system, and long-term complications with the disease can cause death (Centers for Disease Control and Prevention, 2013). Fortunately for Natasha K. her neurosyphilis was diagnosed and treated with the help of Sacks with penicillin. Not only did he recover, but he maintained the “mild disinhibition” (Sacks, 1998, p.104) that he desired. His case is just one of many cases in Sacks' book that explain the neurological basis of behavior..