604 



THE POPULAR SCIENCE MONTHLY. 



hand, the man of superb ability is precocious just because, having a 

 finer brain to start with, he is raised above the average mental stature 

 of his years. He rather resembles a tree which shoots at once above 

 the surrounding trees, though it may mature and bring forth fruit 

 later than they. Nineteenth Century. 



[Concluded.] 



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a 



WOODS AND THEIR DESTRUCTIVE FUXGI. 



By P. H. DUDLEY, C. E. 



II. 



AT the close of my former article I described the conditions which 

 are favorable to the growth of the fungi on woods. In this ar- 

 ticle I present a few examples under similar conditions, to show what 

 takes place as the result of such growth. 



Fig. 10 is a representation of a typical example of decay at and 

 below the ground-line of railway-signal and telegraph poles, sign and 



fence posts. In the case illustrated, as in a large num- 

 ber of other cases, the sap-wood forms part of the 

 pole, the bark only being removed. At the ground- 

 line the ever-present spores of some of the fungi 

 have germinated, under the influence of the moisture, 

 warmth, and air, and have sent out their delicate my- 

 celia over the wood, the threads penetrating any season 

 cracks or fissures, thence piercing and growing in the 

 wood-cells ; the manner of growth is not only interest- 

 ing but wonderful, and almost leads one to think, for 

 an instant, that the fungi, like animals, have instincts 

 to protect them in their development. Certainly I do 

 not wish to convey that impression, but rather to assert 

 the fact of their certain growth and the consequent 

 destruction of the wood, w T hen the conditions before 

 mentioned are present. 



The figure shows a section from a telegraph-pole 

 of black spruce (Picea nigra) ; the opening at the 

 ground-line was sufficient for the admission of the 

 necessary air to carry on the development of the my- 

 celia and the fermentations, but not large enough to 

 allow the wind and heat to dry up the moisture and 

 check the decay ; nor was the opening made until a 

 long time after the internal decay was well advanced, 

 the breaking away of the tissues of the wood occurring 

 more from the iuside than the outside. In unpainted poles especially 

 of this wood so exposed to the sun that an exterior shell may be dried, 



I 



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t ! 



Fig. 10. 



