< have varied from time to time. This elasticity or power of modification in details, without in any way affecting the fixity of the general characteristics and principles of the whole, is a source of the strength and endurance of the Constitution through all the vicissitudes and changes involved in the development of political opinion. The British Constitution, in its present form, is the result of many centuries of growth and of many political influences. The early history of its origin and development is involved in obscurity, like that of most other political institutions. Until the last two centuries historians said little of civil institutions, and all Governments such as that of England arose before the time of written history, Even at the present time it is based largely on tradition and immemorial usage. To understand the Constitution of England (says Amos in his work on the English Constitution), existing and immemorial institutions must be studied as well as the following classes ot authorities :— (1) Written documents of the nature of solemn engagements made at great national crises, between persons representing opposed political forces. Such are the Great Charter and its several confirmations and amended editions, the Petition of Rights, and the Declaration of Rights,