Thomas smiled at the invitation. "I should like that very much." He's fond of Biffy, he wouldn't mind visiting the odd little house in the woods. He'd heard the population had grown.

"Might you come to tea before that? It's only that Cobweb has been sneezing rather a lot." Thomas had a colony of four rats now, all young males: Cobweb, Mustardseed, Peaseblossom, and Moth. "His chest sounds congested."

It was a trick one of the vet technicians had taught him to listen for labored breathing or congested noises. He felt a bit silly holding a rat up to his ear like a telephone, but it worked.