When I first noticed this thread I was very sleepy and hoped it would teach me something about the ends left over from sticks of steel. (Some people buy these drops at tremendous savings.) Then I dozed off.
Still groggy after my nap, I discovered Rupert was prince and decided his drops must be a patent medicine that somehow managed to hold on into the 21st century. Now, a little more awake, I find they're hardened glass and am about to watch the video.
This could be interesting.