Holmes and Watson are on their way back to Baker Street from a freshly wrapped-up case when they hear shrieking from around the corner, and naturally they charge around the corner to see what's happening. What's happening turns out to be a giant snake with a mirror for a face. They get the woman it has cornered out of the way, and Watson goes for his revolver, but before he can bring the snake down it gets its face over both of them and they're somewhere else.
None of those are particularly new to Watson either, though he wouldn't be surprised if the formulae of their painkillers and antiseptics were subtly different given that they have different plants.
Watson soaks up vocabulary and local best practices. The fact that basically everyone starts out with excellent baseline health affects diagnostic assumptions a bit, as well as being heartening.
The lack of children is probably also good for public health; children are delightful but they do tend to catch and spread every disease they possibly can.
"Children where I'm from start with bodies unused to any diseases, and become resistant after encountering them."
"That is lucky. We have ways of doing that for a few diseases, but it's harder than simply making the person that way."
Watson describes the symptoms of smallpox, cowpox, and cholera, "but I don't know if you have the exact same ones here, and I don't know how to prepare the specific treatments, only the general idea".
"I'm not surprised we have different diseases. The general idea is to get the body used to the disease in a weakened form so the strong form can't get them."
"Yes, I did worry about that. But anything I might have had when I arrived would be either gone or showing symptoms by now."
"It's a bit too late to quarantine everyone I've spoken to on this round, but if in your opinion I should avoid people for a while I could do so."