What is Actus Servi In Iis Quibus Opera Ejus Communiter Adbibita Est, Actus Domini Habetur?

Legal Definition
The act of a servant in those things in which he is usually employed, is considered the act of his master. Lofft, 227.
-- Black's Law Dictionary
Legal Definition
The act of a servant in the sort of work in which he is generally employed is that of the master.
-- Ballentine's Law Dictionary