I had been wanting to read this for a while, but it slipped my mind until I saw a thread titled "The Body Snatchers." I was unfamiliar with that title, so I sought this one, since being reminded of it.
I did not realize that it was such a short story; I think the film version with Karloff, Lugosi, etc, did a great job of embellishing it. For films usually must skip many details, but here, a few more were needed.
I had already read several of Robert Louis Stevenson's stories, both adventure & horror. Though I had not thought of him as an author of horror stories, this one is actually a bit creepier than its film version, because it includes the characters' thoughts.