I have several times suffered from them, and would much rather be severely stung by nettles than undergo the fierce irritation, mixed with dull heavy pain, which always accompanies the presence of these hairs. With me, as I suppose would be the case with persons of similar organization, these hairs cause large, hard tubercles to rise, just as if potatoes had been placed under the skin. The hairs of the Processionary Caterpillar have a similar effect, and in France the authorities have several times been obliged to close the public gardens for months, so severe was the pain which the caterpillars inflicted on persons who passed through the spots infested by them. MUD WALLS. There is a mode of wall-building which is much in vogue in some parts of England, and has much to commend itself. This is the Mud or Concrete Wall. At first sight, the very name of a mud house gives an idea of poverty and misery, and is apt to be connected with hovels and pigsties. Mud walls, however, if properly built, are far warmer and drier than those of brick, and are even preferred to those of stone, when the latter can be easily and cheaply obtained. In Devonshire, for example, where even the cattle-sheds, or “linhays” (pronounced _linny_), and the pigsties are made of the rich red stone of the county, it is a common thing to see village houses built of mud. Sometimes the houses are built of stone to the height of some ten or twelve feet, and the upper parts made of mud. [Illustration: NEST OF TERMITE.] [Illustration: MUD WALL.] If the builders are in any way fastidious, they make their walls of a uniform surface by placing two rows of planks on their edges at a distance from each other proportionate to the thickness of the wall, pouring the mud between them, and, when it has sufficiently hardened, shifting the planks. This, however, is not necessary, and detracts much from the picturesque look of a genuine mud wall, especially when it is of that rich red which characterizes the Devonshire soil. These mud walls are locally known by the name of Cob. * * * * * WE have not to go very far in Nature to find good examples of the strength which can be attained by mud walls. In all parts of the world where Termites, popularly but wrongly called White Ants, are to be found, the strength and endurance of the mud wall can easily be tested. Of gigantic dimensions when compared with the size of the architect, they not only endure the rain-torrents which wash over them, but can sustain the weight of the wild cattle, which are in the habit of using them as watch-towers, and this although they are hollow, and filled with chambers and galleries. In Southern Africa these nests are much utilised. There is an animal called by the Dutch settlers the Aard-vark, which feeds almost wholly on Termites. At night it issues from its burrow, and, being armed with large and powerful claws, tears a great hole in the side, and devours the inmates.