I can’t find out much about this–it mostly shows up on Google in the form of vintage bottles of ink being sold to collectors (I didn’t know there were vintage-ink-bottle collectors until now!), but I did find an interesting mention in an old scientific paper online, called Herring Investigations at Plymouth, written by E. Ford, A.R.C.Sc., Naturalist at the Plymouth Laboratory. (That’s a massive PDF file and I’ve had trouble loading it to completion, just so you know.)
It seems Mr. Ford wished to discover “upon what year-class or year-classes of herring was the season’s fishery of 1924-1925 concentrated,” and “Did the fishes landed throughout that season appear to conform to a single morphological type?”.
To that end, he and an assistant examined two to three hundred herring a week, noting their sex and maturity, measuring them, putting three scales on a microscopic slid, then attaching a linen label to the head of each fish by means of a safety pin and boiling the fish in lots of about 50 in order to obtain clean skeletons (so they could count the vertebrae).
But there was a problem: “At an early stage of the work an number of records were lost due to three causes,” the first of which was “Identification labels became unreadable as the result of boiling.” Notes Mr. Ford:
The first of these difficulties was overcome by writing the serial number of the fish in marking ink, sold under the commercial name of “Melanyl,” on linen tape.
So there you go. And remember: no heating required!
