46 THE LARCH CANKER 
show no such drops, or only a few very small ones, whereas 
the dead segments are not noticeably more refractive than 
the surrounding water, and contain numerous large drops. 
These drops often escape from the dead cells into the surround- 
ing water, and may then cling to the outside of the hyphal 
walls. It was probably these drops which Willkomm (1867, 
p. 206) described as ‘ micrococcusschwarmer ’. Occasionally 
movement can be traced in them, but this is not a necessary 
sign of life. The great variability in the size of the so-called 
‘micrococcusschwarmer’ figured by Willkomm (Taf. xxiii, 
24, E) is against their being bacterial cells (cf. Hartig’s 
criticism on p. 73). 
Willkomm states that the hyphae in culture may bear 
lateral conidia, but though I have observed hyphae with 
laterally borne bodies, like those figured in Taf. xxii, 24 c, 
these bodies never became separated from the hyphae, and 
they showed no inclination to germinate. 
Hyphae of a Penicillium bearing conidiophores and 
conidia often turn up in drop cultures of the Dasyscypha. 
This Penicillium grows on old apothecia of the Dasyscypha, 
and it is often difficult to avoid collecting some of these 
conidia when the ascospores are obtained. 
Pure cultures on nutrient media. The method of obtaining 
pure cultures of Dasyscypha calycina which I have found 
most successful is this. Portions of bark with vigorous 
apothecia of the fungus are placed on wet filter-paper in 
the bottom of a drop-culture chamber, as described on 
p. 42. A sterilized cover-slip is then placed over the top 
and fixed with vaseline. Almost immediately the under- 
side of the cover-slip becomes cloudy with condensed 
vapour, and in the film of water so formed the spores ejected 
from the apothecium remain attached to the cover-slip. If 
the apothecia are giving off spores at the time when they 
are put in the culture-chamber, these may be gathered in 
an hour or two, but generally the chambers have to be 
left till the next day, when sufficient spores will have 
accumulated. 
Two culture-chamber rings are then placed on a slide 
