Note E305 — 51.
Reading edition
"Philip and Jacob," that is, St. Philip and St. James' Day, May 1st. "When flocks were more uniform as to breed and management, lambs used to be separated from their dams on this day, for the purpose of tithing as well as milking."—M. "Requiem æternam," a portion of the Roman Catholic Service for the dead, hence "least requiem æternam in winter they sing" = lest they die in the winter from not having been allowed to become sufficiently strong before being taken from their dams, and thus being incapable of enduring the severity of the weather.