“Perforated sore And drilled in holes, the solid oak is found By worms voracious, eaten through and through.” SIR JOHN BARROW. As the destruction of timber by fungi has been called the _vegetable_ rot, it may not be inappropriate to term the destruction of wood by various worms and insects, the _animal_ rot. We have _four natural enemies_ to deal with: 1st, the _dry rot_, that attacks our houses, &c.; 2nd, the _worms_, or boring animals, which destroy our ships and harbours; 3rd, the _rust_, that eats our iron; and 4th, the _moisture and gases_, that destroy our stone. There are three classes of destructive insects which prey upon timber trees, founded upon the manner in which they carry on their operations--viz. those which feed upon the leaves and tender shoots; those which feed upon the bark and the albumen; and those which feed upon the heart-wood. It is to be observed that some of the insects which feed upon the heart of wood do not cease their ravages upon the removal of the tree; but that, on the contrary, the _Cossus syrex_, of our indigenous fauna, and the larvæ of the _Callidium bajutum_, which are often found in imported timber, continue to devour the wood long after it has been inserted in buildings. There seem to be very few means of defence against this class of destructive agents; and very few trustworthy indications of their existence, or of the extent of the ravages they have committed, are to be discovered externally; and it thus frequently happens that a sound, hearty-looking stick of timber may be so seriously bored by these insects as to be of comparatively little value for building purposes of any description. The soft and tender woods, and such as are of a saccharine nature in their juices, are the most liable to be assailed by worms; those which are bitter are generally, if not invariably, exempt; it is obvious, therefore, that those palatable juices, which are so conducive to their production and propagation, should be got rid of by thorough seasoning, and, if further precaution be necessary, that the infusion of some bitter decoction into the pores of the wood will be an effectual preventive; and for which those woods that are of a regular grain afford sufficient facilities. Ash, if felled when abounding in sap, is very subject to worms; beech, under similar circumstances, is also liable to their attacks; likewise alder and birch; in these woods water seasoning is sometimes found to be a good preventive; the sapwood of oak is also thus improved; the silver fir is subject to them; the sycamore is rather so; alder is said when dry to be very susceptible of engendering them; the cedar, walnut, plane, cypress, and mahogany are examples of woods which discourage their advances. It has been stated that Robert Stevenson (not the son of the “Father of Railways”), of Edinburgh, at Bell Rock