2 14 
W. J. Dowson. 
sown upon sterilised blocks of greengage wood and strips of bark. I n 
hanging-drop cultures of grape-juice agar germination took place 
within twelve to twenty hours. Germ tubes were put out in suc¬ 
cession at or near both ends of the spores (Fig. 3, H), the second 
germ tube appearing some time after the first had reached a con¬ 
siderable length. 
Nearly all the ascospores sown in damp chambers germinated, 
and the first plates of a culture series were in a few days covered 
with small colonies. A brown pigment specially noticeable on the 
light coloured grape-juice agar was produced by the developing 
mycelia. The colonies did not extend over an area more than in 
diameter, but became very much heaped up. They were yellowish 
brown in colour. At the edge of each colony was a distinct blue- 
black metallic glistening border, from which diffused the brown 
pigment which stained the medium in the immediate neighbourhood. 
The heaped up portion which consisted of a tangle of short-celled 
hyphas bore minute drops of extruded liquid of a brown colour upon 
its upper surface which seemed to indicate some kind of metabolic 
activity going on within the mycelium and possibly associated with 
the formation of fruit-bodies (cf. pure cultures). 
In one experiment a germinating conidium was transferred from 
a damp chamber to a Petri dish at the same time as two germinating 
ascospores. The three mycelia which arose from these spores were 
exactly similar in appearance, the conidium producing a mycelium 
of the same characteristic form as the mycelia obtained from the 
ascospores. In old plate cultures in which the agar had dried to a 
thin skin presenting flattened colonies, were found small stumpy 
pycnidia which contained the sickle shaped conidia similar to those 
formed in nature, but rather smaller (Fig. 3, J). 
The ascospores were also sown upon sterilised blocks of green¬ 
gage wood; but time did not allow of these cultures being followed 
up. Cultures of mycelia obtained from ascospores and transferred 
from plates of agar to sterile blocks of greengage wood and bark, 
produced mycelia which spread slowly over the surface of the wood. 
After six weeks’ growth the whole of one side of a block of wood 
was covered with an aerial mycelium consisting of short lax hyphae 
yellowish in the older parts and white where newly formed. The 
mycelium was more luxuriant and spread faster on the bark than 
upon the wood. In these bark cultures it was noticed that the 
mycelium originally placed upon the outer surface, appeared next 
on the inner surface of the block (a small zone of wood was always 
