Lost or stolen or strayed?

One of the cats is missing. We have two, both indoor cats. One of them, Oscar, occasionally tries to make a break for it to the great outdoors. The other, Max, is more of a homebody. Max is the one that's missing. I can't find him anywhere in the house, and although I don't see how he could have gotten out, I did go out and call for him and got no response to that, either. Max has kitty diabetes, so my mommy-anxiety is of course kicking into full gear. Living in a house this old, there are a lot of nooks and crannies, and with a one-year old tagging along I can't search as thoroughly as I otherwise might. So I'm hoping I've just missed him somewhere, except if that's true why hasn't he come out? But if that's not true then where is he?

Here kittykittykittykittykittykittykitty.