Thank you all for the suggestions. (Phred's suggestion is still my favorite. )

Between noon and midnight Tuesday Cassy developed a bald spot between his ears, about a fingerprint size. The vet tested for ... I'm calling it demonic mange due to Cassy's reaction to the test, but that's only approximate as you know. That's not it, so they are testing for ringworm due to the dog next door having it. Apparently the test can take up to 3 weeks to PROVE ringworm in cats, and the vet doesn't want us to lose 2 to 3 weeks of treatment time... so I get to wash my grumpy old man.

I'll keep you updated, but I may not be able to log in regularly. My brand-new laptop quit working last night. Grrrr. I'm on a borrowed computer today, but the loaner isn't really open to my using it often. Now I get to get my new computer fixed.