434 Williamson .— The Origin of ‘ Golden ’ < 9 #/£\ 
and soaked in running water for six hours. It was then placed fora minute 
in alcoholic mercuric chloride, to kill any external spores, washed in steri¬ 
lized water, and placed on a glass ring in a potato dish. All the glass used 
had been previously treated with mercuric chloride. A little sterile water 
was left in the bottom of the dish to keep the air sufficiently moist. In 
a week to ten days a mycelium could be seen emerging from the cut surface 
of the wood. This was a growth from inside the wood and proved on 
microscopic and cultural examination to be identical with the fungus, 
Eidamia catenulcita , isolated from the wood externally. The wood was left 
for several months in these moist conditions and the yellow colour spread 
throughout. No other fungus was found arising from the wood. Single 
spore cultures were obtained from the conidia produced on this mycelium, 
and subcultures of these were used in all subsequent experiments. 
Artificial Production of the Golden Colour in Wood. 
In order to test the effect of Eidamia catenulata on the heartwood of 
normal oak, small pieces of QiLercus robur (about one cubic inch) were 
placed one above the other in wide test-tubes. These were sterilized by dry 
heat at i8o° C. Sterile water was then poured in and the wood left to soak 
for some hours, after which all but io c.c. of the water was poured off. This 
left enough water at the bottom of each tube to supply a sufficiently moist 
atmosphere for the fungus. The degree of moisture would vary in the 
different blocks of wood according to the position in the tube, the moisture 
decreasing from the lowest block upwards. The blocks were then inocu¬ 
lated with spores of E. catenulata and left at laboratory temperature. In 
a week the fungus was growing well, and the oak soon had the yellow colour 
externally, owing to the production of many chains of yellow conidia. In 
four months the wood was definitely yellow, and cubes split after six 
months showed exactly the same golden colour seen in some of the original 
‘golden’ oak which had been left in damp air. In these experiments a 
control tube of oak which had been treated in exactly the same way as the 
other tubes, apart from inoculation, was kept for comparison. This wood 
showed no change in colour or alteration in contents as far as could be seen 
macroscopically and microscopically. 
The difference of moisture in the different blocks was not sufficient to 
make marked changes in the growth of the fungus and consequent colour of 
the wood. In this the effect of E. catenulata on oak is not comparable to 
that of the unknown fungus causing * brown ’ oak. In the latter Professor 
Groom (2) found that the brown colour was assumed only when the heart- 
wood contained moisture exceeding a certain minimum and falling short of 
a certain maximum. The blocks in the middle of each column in the tubes 
inoculated with the unknown fungus changed to the brown colour, and not 
those at the base or top of the tubes. 
