 To the index now, the FDA tonight giving the green light to a new drug to treat Alzheimer's, offering hope to millions of patients. Casunla, made by Eli Lilly, is only the second drug available to slow the progression of the disease in its early stages. It's administered through a monthly infusion and has some risky side effects, including potential swelling and bleeding in the brain. When we come back, we meet some of the residents of America's first zoo.