The gist is that there is a positive correlation between the accumulation of freely available ebooks by individuals and the sale of hard copies of such material.
That certainly is something worth stopping to think about for a moment.
Perhaps it presents an opportunity to re-evaluate the real impact of the dissemination of such material online... Sounds almost like effective marketing to me.
Batracobdella algira - Leeches and amphibians frequently interact with each other in nature, usually with the amphibian serving as food for the leeches, whether as eggs, tadpoles...