'Salem's Lot is maybe my favorite King book of all, so I love questions like these! Here goes:
1) It was Danny Glick who entered the McDougall home. His invitation could have been as simple as the baby seeing a face at the window and smiling/waving, indicating welcome. Barlow was able to overcome that stricture when he entered the Petrie home because of his great strength and age.
2) Mike may have been surprised that it was locked, but that doesn't mean that it didn't happen occasionally. In this case, the family chose the lock when other families may not have. No big deal. If it had said he was
shocked, that would have been a different thing altogether.
3) Many supernatural stories, both written and on film, juxtapose evil against the Catholic church more than any other. When something potentially supernatural happens in most movies/books, do they waltz down and get the closest Baptist minister or Momon bishop? Heck no! It's always a priest. Even Barlow taunts Father Callahan with the fact that he was 'old when your people (Catholics) were hiding in sewers and painting fish on themselves" (or something along those lines--I'm too lazy to go get the book for the exact quote--lol). The book tells us that Mark's parents were casual Christians (Methodist, maybe? Can't remember for sure, but Mr. King tends to fall back on what he knows when it comes to religion), so it's possible that he was already baptized. However, the Catholic Church recognizes baptism from most Christian denominations (he wouldn't have to be rebaptized), so I suspect he was not baptized prior to his time in Mexico. Staro is right--there is more to joining the Catholic Church when you're older than a baby than just holy water--there is catechism (knowing the basics of the faith and proving you know them) and anointing with oil as well. Maybe it is the fact of the religion being so old and the rites being nearly as old that makes that particular faith seem stronger against evil than other Christian religions, all of which grew from this religious root? Something to think about, anyway
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