>>..."penny dreadfuls" meaning small cheap books poorly written, vulgar in content.

That is also the only definition of penny dreadfuls I have ever known. WON, maybe you should write this Schwerdt person and ask him what his source for this information is. It'd be interesting to find out.

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EDIT:

I did a bit of net surfing myself and it seems that the Herald reporter might have mixed up his information. Apparently, vinegar valentines and penny dreadfuls are the same thing. They weren't called dreadfuls because of the quality of the printing but because they were sent to people you didn't like and were caustic or comical - something 'dreadful' the receiver would not appreciate.