Tolley's Tax Deformity - a new disease?

I am slightly concerned about these...growths that I've found on my Tolley's Tax Handbooks...what could be in there?

Are they buboes? Should I be using the Medieval approach of protecting myself with sweet smelling nosegays?

Is it the sign of an infestation of book-flesh eating bugs? Will they eventually burst out from the spines in a spray of paper shreds? Like the chestburster from Alien, but with more glue, and less blood?

I am afraid.

If you don't hear from me by the end of January, send in the search parties. Although I'd recommend they be wearing with HazMat suits, probably Type 1.

And bring tongs.