Going "back" to the Demeter log in my paper edition, I experiment once again a feeling that had hit in my previously readings of Dracula. This novel in its published order is presented like a collection of paper. As if someone has done an investigative work, maybe of journalistic nature to figure out what happened and this would be the result.
I believe it is stated at the end of the book.
The long description of J.H doesn't feel like it but the correspondance of Mina and Lucy, followed by press article, follow by a few weeks of seal log really does.