5(t Dry Rot in Timber. 



tions may prove useful to those who have not had opportunities 

 of coming in contact with this destructive agent. The name, dry 

 rot, is apt to convey an erroneous impression of the nature of the 

 disease, which is largely due to the presence of moisture, and 

 misconception prevails to some e>ctent. I have seen badly worm- 

 eaten timbers described in reports as being in a state of decay 

 occasioned by dry rot. The worm is an insidious fellow, with a 

 taste for sapwood, which ought never to be allowed in a house or 

 in furniture, but his ravages are not to be compared in respect 

 to the force and rapidity with which dry rot, in circumstances 

 favourable to its germination, attacks and wrecks the woodwork 

 of a building. The mycellium will penetrate, and force its way 

 through brick and stone walls, and even concrete, and by means 

 of spores will cross intervening spaces and attack timbers in 

 predisposing circumstances. Dry rot is occasioned by fungi, of 

 which the most destructive is merulius lacrymans. This soft and 

 pulpy growth penetrates the cellural tissues of the wood in every 

 direction, with great rapidity, absorbing the secretionary sub- 

 stances, and leaving in many instances little more than dry dust. 

 A moist, warm, stagnant atmosphere is the condition most favour- 

 able to the growth of the fungus. An impervious and insuffi- 

 ciently drained site and the use of unseasoned wood, are also 

 contributory causes, and it is believed that the timber may contain 

 the germ of the disease before being imported into this country. 

 Buildings are most subject to attack when new, owing to the 

 absorption of moisture from the new walls and plaster by the dry 

 wood ; and the use of linoleum, waxcloth, or other impervious, 

 coverings on the floors, when the buildings are in this state, is a 

 fruitful cause of disaster. Practical illustration of such points 

 as these will follow : — I have selected six cases which I take to 

 be in some respects typical ; two concern private houses, the 

 others relate to public buildings. In regard to the first class, 

 although what I have to say would not injure the character of 

 the subjects, not having the proprietor's permission I am not 

 free to reveal their identity ; but such reservation is, I think, 

 unnecessary in regard to the public buildings, and their identifica- 

 tion may help to give proportion to the mischief resulting from 

 the decay. I should explain that it has only recently become 

 the practice to provide against ground damp by covering the 

 earth under the lowest wooden floors of buildings with some 



