A more generally effective device by which discussion is limited and the transaction of business is facilitated is that known as "closure by compartments," or "the guillotine." When this is employed the House in advance of the consideration of a bill agrees upon an allotment of time to the various parts or stages of the measure, and at the expiration of each period debate, whether concluded or not, is closed, a vote is taken, and a majority adopts that portion of the bill upon which the guillotine has fallen. In recent years this device has been employed almost invariably when an important Government bill is reserved for consideration in Committee of the Whole. Its advantage is the saving of time and the ensuring that by a given date final action upon a measure shall have been taken. Prior to the middle of the nineteenth century liberty of discussion in the Commons was all but unrestrained, save by what an able authority on English parliamentary practice has termed "the self-imposed parliamentary discipline of the parties."[206] The enormous change which has come about is attributable to two principal causes, congestion of business and the rise of obstructionism. The effect has been, among other things, to accentuate party differences and to involve occasional disregard of the rights of minorities.[207] [Footnote 206: The name was first employed in 1887.] [Footnote 207: Redlich, Procedure of the House of Commons, I., 133-212; Graham, The Mother of Parliaments, 158-172. An excellent illustration of the use of the guillotine is afforded by the history of the passage of the National Insurance Bill of 1911. See _Annual Register_ (1911), 232-236.]