Joshua Pearce takes unusual satisfaction in strolling through Walmart. The shelves laden with toys, household items, tools and clothing inspire in him a certain smugness, a pride in American entrepreneurship. But it’s not because Pearce admires the chain as an empire built by a self-made man. Pearce swells with pride at Walmart because the store is full of mass-manufactured objects that he...
More than 1,800 years ago, the Greek physician Galen came up with a model for how the human body works. Blood, which he called the "natural spirit," originated in the liver and traveled to all parts of the body through the veins. In the left side of the heart, some of the blood mixed with air from the lungs to make "vital spirit," which flowed to all parts of the body through the arteries....