114 TRANSACTIONS OF THE [jAN. 4^ 



have only found a few undeveloped efforts of fructification. 

 FistuUna lie-paiica was found on chestnut wood. The spe- 

 cial habitats of the others need not be mentioned. Theso- 

 higher species of fungi are some of those which induce the 

 so-called " dry rot" in timber, so often considered as taking- 

 place when the wood is perfectly diT. This is a misconception, 

 as it is impossible for decay to commence without moisture, suf- 

 ficient heat, and access of air to supply the amount of oxygen 

 needed in the reduction of the tissue to lower compounds. 

 "Dry rot" was named from the effect produced, and to distin- 

 guish it from the so-called wet rot. It has been an unfortunate 

 designation, misleading many })eople, and causing them to believe 

 that timber will rot when dry, and hence proi)er precautions 

 have not been taken to prevent decay, on the supposition that it 

 would occur in any event. When a fungus has attacked a i)iece 

 of timl)ei-, and subsequent dryness arrested further decay, the 

 tissue affected ci-acks and crumbles to dust, and people often tell 

 me '"there is the evidence of dry rot destroying dry timber" — 

 an efffCt mistaken for a cause. 



The mycelia and fruit of the fungi given in my list all show 

 an acid reaction; and in the decayed yellow pine an acid was 

 associated with a gelatinous mass, insoluble in alcohol, but par- 

 tially so in hot water. A. drop of the latter on evaporating left a 

 gummy lesidue, and small crystals formed, similar to those of 

 oxalate and ])hosphate of calcium. By adding other reagents, a 

 variety of different crystals were produced. 



From the fruit of Polyporns piaicola Fr., a considerable 

 fjuantity of phosi)horic acid, potash, and lime were obtained. 

 The watery extract from this fungus nearly resembles, in compo- 

 sition, the artificial preparations used for the cultivation of 

 moulds, and is quickly transformed by them in a few hours, 

 showing an abundance of yeast cells and rhombohedral crystals. 

 This is a feature of great significance, being an impoitant aid in 

 hastening decomposition, at least. If there is a free aerial giowth 

 of the fungi, drawing its supply of oxygen from tiie air, there is 

 a rapid destruction of tissues, and little is left of the structure. 

 When the air is limited, there is a slower destruction, and more 

 of a fermentative action. In the latter, in the many cases so far 

 studied, I have found an abundance of crystals. The so-called 

 "wet rot "is the result of slow fermentative action, and when 

 produced by the lower order of fungi, Sphieriacei, the mycelia 

 found in the cells are dark-colored and jointed. These mycelia 

 are sometimes of long, and again of nearly si)herical cells, which 

 pierce the cell-walls of the wood and fill the medullai'y rays, 

 making them look dark. Some species fruit in the cells near 

 the outer surface. I have a piece of one of the original oak ties- 



