Tlic Black Zones Formed bij Wood-Destruijing Fungi 39 



was carlMiiiized l)ut the globules reinained intact. Upon 

 healing the acid to Ixnling- the wood dissolved together with 

 more or less of the decomposition products. In cold con- 

 centrated nitric acid the decomposition products were in- 

 soluble but upon heating to boiling the wood dissolved 

 together with the liioludes, formin<>" a l)rown solution. More^- 

 over, tests performed with other sections indicated that the 

 decomposition products in question were insoluble in absolute 

 alcohol, xylene, acetone, ether, petroleum ether, <:4iloroform, 

 carbon bisulphide, and carbon tetrachloride. In addition to 

 this, sections of the ^\'Ood containing the globules of decom- 

 position products were placed in a concentrated solution of 

 chloral hvdrate and kept at a temperature of 55 degrees C. 

 for one week. There was no effect other than a slight swell- 

 ing of the globules. The same sections were then washed in 

 water and dehydrated by alcohol. Part of them were treated 

 with clove oil and the remainder with cedar oil, but the de- 

 com])Osition products remained insoluble in both cases. 



An attempt was made tO' determine more fully the chemical 

 nature of the decomposition products by means of a coaiipara- 

 tive analysis of sound and decayed wood. Sapwood of a log 

 of pignut hickory, Hicoria glabra (Mill.) Britton, which was 

 partially decayed by Coriolus prolificans (Fries) Murrill, 

 was used in the study of the decayed wood and sapwood from 

 a li\'ing tree of the same species (gathered in the spring) for 

 the sound wood. Tn the case of the decayed wood a thick 

 black layer of infiltrated wood sharply demarked the com- 

 pletely decayed wood from the small areas of sound wood 

 remaining, these areas being only in the first. stage of decom- 

 position (Plate III). This black layer, as well as the wood 

 enclosed by it, was very hard. The infiltrated wood was 

 shaved off carefully, care being taken not to include the 

 underlying, uninfiltrated wood. ^" The sound sapwood also 



" The completely decayed wood that surrounded those pieces of wood 

 which remained intact within the log, was scraped off carefully before 

 they were photographed. 



