Can we recognize if people around us are stressed, anxious or fearful without observing their facial expressions, body language and actions or hearing their voice and messages? What about our own stress - assuming we don't rely on heart rate, blood pressure, dry throat, sweating, drops or surges in energy? Yes, we can - by using our nose - as humans, too, recognize and transmit their emotions through chemical senses ...
Dr. Phlox, the Enterprise surgeon, responded to the comment about movies (aka stories unfold on the screen) by answering: "Well, we had something similar a few hundred years ago, but they lost their appeal when people discovered their real lives were more interesting." At this stage of our evolution, virtual characters and screens are taking over our lives. And the growing ranks of cellphone addicts are turning cities into increasingly hazardous hot spots filled with zombified individuals...
Our bodies are rainforests of microbes feeding off the leftovers from our meals and contributing to a variety of body odors. Human skin is inhabited and re-populated depending on health conditions, age, genetics, diet, the weather and climate zones, occupations, cosmetics, soaps, hygienic products and moisturizers. All these factors contribute to the variation in the types of microbes. Population of viruses, for example, can include a mixture of good ones - like bacteriophages fighting acne-causing Propionibacterium - and bad ones - as highly contagious Mesles. Bacterial communities include thousands of species of Actinobacteria, Bacteroidetes, Cyanobacteria, Proteobacteria, and fungi Malassezia....
Many illnesses are associated with distinct odors. Especially those caused by infectious or opportunistic microbes inside the body or on its surfaces. Body odor of someone infected with C. difficile, for example, can appear "swampy", Rotavirus gives sharply sweet putrid smell that some people associate with wet dogs, H. pylori can create a range of foul odors, and pseudomonas infections can smell like grapes and bitter almonds.
You are what you eat. And you smell like your food. Well, it's actually a bit more complicated - as we emit complex combinations of volatile chemicals produced from food by our own metabolic system as well as microbes that call us home. Same foods can be translated into a wide range of odors, depending on the individual.