Either drink through the layers or stir before consuming. Fabulously old-school in style, this sweetened port and old tom gin drink resembles chilled mulled...
For those of you reading the old measurements above and seeing "one wine glass" measurement; no worries, that is not our current, modern wine glass size. Back then 1 wine glass was approximately 2 oz (2.2 to be exact)/ 60 ml (66 ml).
Found a similar recipe in a 1896 cocktail book, Drinks of All Kinds For All Seasons by Frederick and Seymour Davies. The main difference is they used a bar spoon of powdered sugar. The rest is the same. A very nice cocktail, quite complex flavor actually between the gin, port and nutmeg.