or , 
2 
Srare Mvusevcm or NAaturRAL HistTory. 87 
habitats and growth of definite species of fungi is required to best 
adapt the means to accomplish the desired work. Now that knowl- 
edge of the habitats of species of fungi has been acquired, simple 
and effective preventive measures suitable for many cases, without 
treatment, can at once be put into practice. 
The study of the decay of timber used for construction is rendered 
yery difficult in most cases, from the fact that the entire structure of 
the wood may be destroyed by the growth of the mycelium, or its 
fermentative process, of the fungus without fr uctification taking place. 
This is especially true of railroad ties and bridge timbers. So little 
is seen in proportion to the destruction accomplished, it is due to this 
feature more than to any other, that the true function of the fungi on 
wood is not more generally understood by users and consumers of 
timber. It is not strange the idea is so prevalent that fungi are the 
accompaniments, instead of the cause of the decay of wood. A 
growth of mycelium, nearly similar to that shown in Fig. ES ot 
fungus on the under side of a plank, as in station platforms or 
between boards when piled in close contact, has not been sufficient 
= 
in most eases to call attention to the injury, if not the destruction of 
the plank or timber upon which it is growing. 
Fig. II shows the mycelium of Polyporus radula, Fr. growing on 
the under side of a plank from a station platform. After the myce- 
lium has run over the wood ina dense mass, then, by means of the 
fluids it generates —some of them haying an acid reaction — the fibers 
or wood cells are softened and penetrated by the mycelium, and in 
this way the process of disorganization is carried on. 
This causes the wood to shrink, crack, and finally fall to pieces. 
The mycelium of many other species of the higher Fungi differs 
from this to some extent, but the final effect of its growth on and 
through the wood is to destroy it. Besides the visible mycelium there 
are many other growths and ferments, invisible to the. eye, which 
‘cause a rapid internal decay of large unseasoned painted blocks, such 
as truck bolsters, transoms, buffers, dock timbers, and end sills to cars. 
In warm and damp weather it is not uncommon for such growths to 
oceur upon timber when piled in close contact, according to the species 
of wood and fungi, in three to eight weeks. In this vicinity the tim- 
per on which such growths have started may not be considered sutf- 
ficiently injured for construction —to be rejected. If it is thoroughly 
«Figures I, II and III are from my paper entitled “Woods and Their 
Destructive Fungi,” in the Popular Science Monthly, August and Sep- 
tember for 1886, and are used by Pe of the editor, Prof. W. J. 
Youmans. Pon 
