Heap's Law

[MarcoP]

The change in slope in VMS-B coincides with the transition from Herbal-B pages to Biological pages.
My guess was that it is around 3300 words.

It is a very clear change in trend, showing that the Bio-B text is more repetitive or has a smaller vocabulary.

Thank you, Rene!
If I counted words correctly, the Bio section starts  at word 3445.
BTW, it's interesting that there is no clear "jump up" at the start of the new section, just a flattening. As if the new section, more than bringing in new words, simply marked a more consistent vocabulary, as you noticed. It is as if the "herbal" pages were more independent of one another, each "plant" introducing several new (unique?) terms, while Q13 is more uniform.