Robert F. Kennedy Jr. , who is running as a third party candidate for president, made news this week for his deposition from 2012 that "a worm ... got into my brain and ate a portion of it and then died." Michael M. Santiago/Getty Images hide caption
This is what's called a "specimen lot" — a large mason jar holding smaller vials of parasitic worms gathered by a researcher in 1927. The Smithsonian collection has more than 120,000 specimen lots. Kristin Adair/NPR hide caption
The dwarf tapeworm, or Hymenolepis nana, is the most common tapeworm in humans. It's 2 inches long at most. Courtesy Peter Olson, Natural History Museum, London hide caption