As Mick mentions in his comment, "to deem healthy" is a bit aged-fashioned although not, I do think, ample that you shouldn't learn the way to make use of the idiom. I wouldn't contact it "Victorian" English, as it is a phrase that sees typical use even these days. It's https://catgroominguae60470.blazingblog.com/36716293/not-known-details-about-how-to-take-care-of-a-cat-uae