When documenting a birth in genealogy records, we are told to get as close to the primary source as possible. So here is what I found for my grandmother. First we have the family Bible:
This is generally a somewhat reliable source, but this depends on who did the recording. I notice that the first four entries are all in the same hand. The later ones are not. Plus in another spot in the Bible it says the Bible was "given to her by her mother". I don't know anyone who refers to themselves in the third person. So my guess is that Ellen made those first entries and the later ones were made by one of her daughters. At the bottom you can see the entry for my grandmother : October 24, 1898.
Next I found the register page for the city of Newton where my grandmother was born:
There at the very bottom, entry 679 was recorded in the register on January 16 of 1899. For a long time, I thought that was it. I'd found my primary source. Then Ancestry made a whole new set of Massachusetts birth records available. You see, what I'd completely forgotten was that my grandmother would have been a home birth. All of Ellen's children were. Attended by a doctor perhaps...or not. That was how it was done back then. And in that new set of records I found this:
Now I know by the date at the bottom that this is the source of the information for the register entry. I also see a physician's name on the right side and the place of birth is Eddy Street. So this was the official physician's record of the birth for the city. I don't know if he made notes and transcribed them later, or just filed a card based on information supplied by the parents when he made a home visit, but I would guess this is about as primary as a source could be.
Always keep looking. Never give up.