Sir Everard Home (1756 - 1832) was a prominent English surgeon and anatomist (and, possibly, plagiarist). This multi-volume work was published in 1828 (London: Longman, Reese, Orme, Brown, and Green).
This work's only mention of Newfoundlands occurs in Volume 5, in the chapter entitled "On The Nerves of the Placenta." In this section Home describes a number of cases in which pregnant women had certain experiences which directly affected the fetus (such as the woman startled by a one-armed sailor while pregnant; she later gave birth to a one-armed child!) Here's how a Newfoundland dog figures into Home's curious theory:
A lady of a nervous habit, who had had several healthy children, during a state of pregnancy, upon opening a door, was surprised by the Newfoundland dog, with which she was familiar, suddenly in playfulness putting his two fore paws upon the sides of her belly. The child, in all other respects well formed, had two claret marks where the paws had been applied. These I afterwards removed. (190 - 191)