I have some difficulty in understanding the bracketed sentence. Please do me a favor.
By 19 century, various social clubs and press societies were being created as informal, shared spaces for journalists to meet to discuss their concern about what was rapidly becoming-in the eyes of many of them - a profession (this when the drinking of toasts from skull was not an unkown practice at some of these clubs.)
Thanks a lot.
It means just what it says. They drank toasts (drinks, usually alcoholic) from skulls, probably human. It is not a common practice.