On Polyporus squamosus Huds. 279 
We cannot be certain that these hyphae belong to P. squamosus 
because the inoculated surface was an old one. Similar wounds, 
however, were examined and the amount of discoloured tissue below 
the wound-surfaces was much smaller than in the case of the one 
inoculated ; hence it is a reasonable supposition that the greater 
discolouration associated with the inoculated wound was caused by 
P. squamosus. 
Hyphse had penetrated only to a slight extent the new wounds 
which had been inoculated, in fact they were only seen in the 
vessels quite close to the surface. Since both the wounds had been 
treated in exactly the same way, and had been subject to exactly 
the same conditions throughout, it appears conclusive that the 
nature of the wound has some effect on the rate of penetration. 
In the case of the old wound, possibly the layer of dead cells present 
on the outside forms a suitable substratum for the first growth of 
the mycelium. Or it may be that the living cells of the new wound 
have some direct toxic action on the growing hyphae. 
(b). Spore inoculations. Spore inoculations were made in the 
autumn of 1912 on the trees already mentioned. The spores were 
collected in large numbers, and placed on old and new scalpel 
wounds in large numbers in some cases, or mixed with sterile 
water, the inoculations being protected in the usual way. 
A number of inoculations were made in this way on November 
16 and also November 20, 1912. Those of November 20 were made 
with large quantities of spores. A twig was removed on November 
22 (the wound was fresh at time of inoculation) and spores were 
washed off and examined. A very few out of the large number 
showed early stages of germination. 
On November 27 the same method of examination was repeated 
for wounds of both types. None of the spores washed off showed 
any signs of germination, but on scraping off the surface, spores 
with long germ tubes were present fairly frequently (Text-fig. 4). 
It seems probable then that after nine days, these germ tubes were 
beginning to penetrate the wood. The hyphse entered the vessels 
near the surface. The penetration of the mycelium from spore- 
infections was very slow. A freshly wounded twig infected with 
spores on November 16, 1912, shows hyphse in only the three or 
four external layers of vessels by April 17, 1913. 
Summary. 
1. Polyporus squamosus has been raised for the first time in 
pure culture on Elm wood blocks from the spores. The fungus has 
been grown also on other kinds of wood. 
