A modus is a composition time out of mind.2 Gwill.591.
A modus is a real composition founded on an agreement.2 Gwill.689.
The only difference between a modus and composition is, that the first is, time out of mind, and the last, only a late agreement. Id.612.4 Gwill.1397.
A custom to pay 4d. an acre in lieu of the agistment tithe of barren cattle above a year old, if fed one month in the parish, is good.3 Gwill.1048.
A custom to pay 3d a head for sheep agisted between Candlemas and shearing day, and a fleece of every hundred every month for all sheep brought into the parish after the 2d of February, and shorn therein is bad.3 Gwill.1048.
To constitute a good MODUS, it seems necessary that it should be such as would have been a certain, fair, and reasonable equivalent or composition for the tithes in kind, before the year 1189; and, therefore no modus for hops, turkeys, or other things introduced into England since that time, can be good. Bunb.307.
A modus of one penny for every sheep, and a halfpenny for every lamb brought into the parish after Candlemas, and sold out before shearing time, is not an agistment, but a wool modus, 4 Gwill.1462.1468..