This book, by Lyall Watson (1999) is of interest to those who want to be more aware of the sense of smell. Jacobson's Organ is a little discussed auxiliary olfactory sense organ, named after the scientist who discovered it. It can be clearly seen in reptiles and mammals, from snakes to horses and cats, who all have these two small openings in the nasal cavity leading to a separate neural pathway going straight to the brain, that instantaneously senses chemical information about dominance, sex, and danger.
Apparently humans also have this organ in the early stages of development in the womb, but as we grow into adults it appears to become vestigial, at least to the naked eye. Further studies have shown however, that this organ appears to be the part of us which is sensitive to pheromones, the basis of that good sexual chemistry we are all in search of. Something invisible and without the kind of smell that our more familiar olfactory sense can register, but which is there nonetheless and can be highly influential in our relationships, even to our moods and sense of security, and our understanding of the physical realities around us. Watson extrapolates that Jacobson's Organ is the source of our intuitions, which is the controversial part, along with exactly how functional and influential this organ is in most humans.
There is no hard proof (yet) that this sixth sense, closely related to smell, is as fully functional in adult humans as it is in many of the other creatures we evolved along side of. The natural history examples in the book impart a lot of information about how different reptiles and mammals, from snakes to lions navigate reality with great refinement by employing the sense of smell in concert with Jacobson's Organ. He also gives lovely examples of how plants evolved to directly appeal to those senses as a means to enlist outside aid in their own reproduction, to reach out and attract other living beings who are capable of being attracted.
I know we are very complex organisms, but still I'm surprised that we don't already know absolutely everything about how our bodies function by now, considering the tools we have developed, and the close study we have made of ourselves.
We do know now that there are many chemical reactions in the environment around us that we become aware of through our skin and sense of smell which affect us deeply, both emotionally and physically, in ways we are not consciously aware of. For example, human mothers bond with their babies and vice-versa with an unerring sense of smell as identifier, as do other mammals. We know that we each have our own particular aroma (not related to uncleanliness, but to our own chemistry) that is emanating from us all the time.
Animals, and most famously dogs, can discern individuals by their unique smell, proving these emanations are most definitely there, whether humans are registering them consciously or not. We may not need to be conscious of them, in order for them to have a purpose, to influence us and to reveal significant information we require about each other and the world. It may well be that the Jacobson's Organ in us is functioning without our being aware of it, or knowing yet exactly how it works.
We do know that so many other mammals rely on it and also that we are more similar to them in many more ways than we are different. We do know that we ourselves are greatly affected by very subtle differences and changes in our environment and our experience of other people and creatures. We do know that we are animals ourselves, first and foremost. Jacobson's Organ implies that there is another very sensitive sensory system at work taking in the chemistry of life around us, a true sixth sense, connected to the oldest and deepest part of our brains, influencing us without our being completely aware of it. I like the idea.
The book is available through Amazon or Google Product Search.