The command "brew install boost" works for me on my MacOSX, but it installs the latest boost 1.57. How to use brew to install the older 1.55?
You'll want to run brew install boost@1.55
$ brew search boost
==> Formulae
boost ✔ boost-build
boost-python boost-python@1.59
boost@1.57 boost@1.60 ✔
boost-bcp boost-mpi
boost-python3 boost@1.55 boost@1.59
==> Casks
boostnote focus-booster
iboostup nosqlbooster-for-mongodb
turbo-boost-switcher