Falstaff's worthy body-guard are getting tired of hard knocks in fight; Nym compares their late activity to a somewhat florid 'plain-song' [meaning an extempore descant, as explained above]; Pistol says it is a 'just' plainsong. A 'just' plainsong would mean that the singer had managed his extempore descant 'without singing eyther false chords or forbidden descant one to another.' Similarly, there is little doubt that both Ancient and Corporal managed to take a part in the skirmishings with as little damage as possible to their sconces.
The speech of the boy at l. 41 hardly enrols Bardolph amongst music lovers. At all events he stole a lute-case, and seems to have liked it so much that he carried it 36 miles before his worser nature prevailed on him to sell it for 1-1/2d.
The next quotation still concerns Jack Falstaff and his crew, all of whom (and strictly in accordance with history) seem to have been sound practical musicians. This time they are speaking, not of descant, but of Prick-song. The chiefest virtue in the performance of Prick-song, by which Falstaff and Nym probably understood both sacred and secular part-music, is that a man should 'keep time,' religiously counting his rests, 'one, two, three, and the third in your bosom,' and when he begins to sing, that he should 'keep time, distance, and proportion,' as Mercutio says Tybalt did in his fencing, see Romeo II, iv, 20.
All this is thoroughly appreciated by Falstaff and his corporal in the following lines:—
Merry Wiv. I, iii, 25.
Falstaff (of Bardolph) ... his thefts were too open; his filching was like an unskilful singer, he kept not time.
Nym. The good humour is to steal at a minim's rest.
['Minims' is a modern conjecture.]
The metaphor is of an anthem or madrigal, say in four parts. We will suppose the Hostess of the 'Garter' is taking the Cantus, a tapster the Altus, mine Host the Tenor, and Nym the Bassus. The three former are all hard at work on their respective 'parts,' one in the kitchen, another in the taproom, the third in familiar converse outside the front door. But Nym has 'a minim rest,' and during that short respite takes advantage of the absorbing occupations of the other three 'singers' to lay hands on whatever portable property is within his reach. 'A minim rest' is not much—but the point remains. Any musician has had experience of what can be done during a short 'rest'—e.g., to resin his bow, or turn up the corners of the next few pages of his music, light the gas, or find his place in another book.
By an easy transition we pass to the following:—