Many families, of which the laird was often the best farmer in the district and his own factor, have disappeared. The fine houses, with their parks and shootings, are let to strangers, who come for a few weeks or months, and then leave it in charge of a caretaker. Before this recent development, the "family" lived all the year round upon the land; they spent their income chiefly in wages to the country people. Where once forty or fifty people were employed all the year, there are now but three or four. The big house with shuttered windows and weed-grown walks, is a distressing and saddening spectacle. Of course such changes must occur. The farmer's and the cottar's children are now carrying out in Canada, Australia, or the United States, what was done in Scotland from 1780-1830. India, South Africa, and China have been developed by the brains and hold the graves of many of the laird's sons. Yet this poor old country, abandoned of her children, shows signs of revival. Both the poor and the rich are beginning to find out that a country life is healthier, quite as interesting, and sometimes quite as profitable as the overcrowded city with its manufactories, mills, and offices. All new countries are beginning to fill up, and there is some hope that a new and vigorous development of farming may make the countryside once more vigorous, prosperous, and full of healthy children. CHAPTER XII ON PLANTS WHICH ADD TO CONTINENTS Lake Aral and Lake Tschad--Mangrove swamps of West Africa--New mudbanks colonized--Fish, oysters, birds, and mosquitoes--Grasping roots and seedlings--Extent of mangroves--Touradons of the Rhone--Sea-meadows of Britain--Floating pollen--Reeds and sedges of estuarine meadows--Storms--Plants on ships' hulls--Kelps and tangles in storms--Are seaweeds useless?--Fish. The way in which the savage, rugged, inhospitable Britain of the Ice Age changed into our familiar peaceful country formed the subject of the last chapter. But plants do far more than cover the earth and render it fertile, for some of them assist in winning new land from the sea or from freshwater lakes. The Sea of Aral, for instance, or Lake Tschad are rapidly becoming choked up by reeds and other vegetation. Blown sand from the deserts around is caught and intercepted by these reeds, so that fertile pastures are gradually forming in what used to be the open water of a deepish lake. By far the most extraordinary of all these plants which form new land are the Mangroves. They are only found in the tropics or sub-tropical regions, and are always along the sea-coast. It is where a river ends in a delta, dividing into intricate and confused irregularly winding creeks, that the mangroves are especially luxuriant. Such a river will have probably flowed through hundreds of miles of the most exuberant tropical forest, where growth is never checked by the cold grasp of winter.