The Two Kinds of Cell Growth

In 1838, Matthias Schleiden, a botanist, and Theodor Schwann, a physiologist, both working in Germany, had claimed that all living organisms were built out of fundamental building blocks called cells. Borrowing and extending this idea, Virchow set out to create a “cellular theory” of human biology, basing it on two fundamental tenets. First, that human bodies (like the bodies of all animals and plants) were made up of cells. Second, that cells only arose from other cells—omnis cellula e...

 Naturalism Improves Perception

Nature study also heightens our perceptive abilities: we see, hear and smell more, and more keenly, because of them. In the cities, our senses tend to atrophy. The relentless commercial badgering of signs, and the general dullness and ugliness of city landscapes, push the urban walker into the safe cocoon of his mind and further out of his senses. Simply spending time out in pastoral or wild landscapes counteracts this tendency. Spend a day in the woods and you will begin to hear a bit more a...