LULU GARCIA-NAVARRO, HOST:
The osmocosm - never heard of it? It's all around you, influencing you in ways that you can't imagine. And science author Harold McGee would like us to go on a voyage of discovery to experience it. In his new book, "Nose Dive: A Field Guide To The World Of Smells," he examines all things olfactory from the smell of the creation of the universe to the sweaty, animalistic stink of a ripe passion fruit. He joins us now from San Francisco. Welcome.
HAROLD MCGEE: Thank you, Lulu.
GARCIA-NAVARRO: So this book is 600 pages, I should say. And you spent 10 years researching and writing it. Why?
MCGEE: Well, my usual subject is food and drink. And so I started out thinking that I was writing a book about flavor.
MCGEE: And it turns out that smell is the most important sense when it comes to distinguishing among different foods. Taste and smell together make flavor. But taste only really tells us about very basic sensations. It's the sense of smell that gives us all the variety. That turns out to be a big subject. I didn't know anything about it before I got started. And it took me 10 years to work my way through it.
GARCIA-NAVARRO: Yeah. You call this a field guide. And you've set it up like one, sort of following your own passions and interests with smells. How did you sort of organize this?
MCGEE: When I started to look at the smells of the world, it then occurred to me to ask the question, well, when did the universe first develop smells so that if a human being were around at the time and had some kind of, you know, interstellar nose to detect things with - that smells would begin to develop? And it turns out to be very, very early long before there was a planet Earth. And so I began with the Big Bang. And then that took me through the route of looking at when the earth did form, how it formed, what its early history was, what it smelled like before there were plants and animals. And I just kind of went from there.
GARCIA-NAVARRO: Yeah. It's something I have never even considered - what space might smell like.
MCGEE: Yeah. And, in fact, I was shocked. Turns out that astronomers have been able for years now to be able to detect from a long, long distance molecules that are floating out there in interstellar space. And not all of those are molecules that we can smell. But there are things like ammonia and hydrogen sulfide, which is the smell of eggs, and even fruity smells and the smell of vinegar.
GARCIA-NAVARRO: I want to talk about excrement. I like the smell of horse manure, for example. But you have an entire section on the different smells of excrement and why we respond the way we do. And I found it really interesting. Can you elaborate?
MCGEE: So excrement is - it kind of goes along with being an animal because animals live essentially by finding and consuming other forms of life. We need to eat things. And we need to assimilate those things. And that means we have this inner chamber where we do the assimilation. And there are always leftovers. There are always wastes. And the innards of animals are prime territory for microbes of all kinds. And it turns out that the life of the microbiome, the activity of the microbiome inside us depends, in large part, on what it is that we're eating. That's why horses, for example, which essentially eat nothing but grass, have a very particular smell. And the smell of omnivores like us and like pigs, for example, have a very different smell that has to do with the diet.
GARCIA-NAVARRO: I also want to talk about apples. You sampled several hundred apple varieties at the USDA apple germplasm collection. So first of all, congratulations to you for that. You know, one of the things that is striking about this book is how much you have eaten of different things. But you caught all these different notes when you were sampling these apples. And there, you take something that is ostensibly the same, but the way that we will perceive it is very different.
MCGEE: Well, yeah. And it turns out - and this is something just worth knowing in general - that smells are composite sensations. We think of an apple as smelling like an apple. But in fact, it's more like a chord made up of different notes. And what we usually get is just the chord. But in fact, if you pay attention, you can begin to pick out the different notes that make up that chord. So the chance to go to a place like the USDA and just walk up and down these rows and rows of apples in harvest season and take a bite out of one and then move to the next tree and take a bite out of another was an amazing experience because the range of flavors that you find in something as ordinary as an apple is really remarkable.
And one of the things I came across that really intrigued me in the writing of this book was the practice in Japan of what they call and what we would translate in English as listening to incense. That's what I find myself doing is, is listening to smells much more than I used to.
GARCIA-NAVARRO: That's Harold McGee. He is the author of "Nose Dive: A Field Guide To The World Of Smells." Thank you very much.
MCGEE: Thank you, Lulu.
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