These days, the dogs that pass by out there on the sidewalk look trim and happy. They’re getting a lot of exercise with their work-from-home humans. They sniff out little mysteries and tag bushes and never glance up to ask their masters, “Why are you home so much? Why so many walks?” The dogs are not having bad dreams. Two neighborhood friends who are both biologists walk by wearing sleek, face-fitting masks. I could call from the door to ask how their dreams are going, but I don’t have to. These two know exactly how microorganisms like to boogie.