Hi Ashe,
Just an FYI on your little Boston who vomits, have his/her pallet checked, may be an elongated soft pallet. Very common with this breed.
I have been showing (allot) and breeding (very little) Bostons for almost 9 years now. We see elongated soft pallets all the time! Sadly it is an issue for all brachycephalic breeds.
Hope that helps some and if you want or need more information feel free to contact me at
nvablondie@aol.com