26 Transactions British Mycological Society. 
Infections were made on red currant (200), fig (20), lime and 
horse-chestnut (20) in a number of different ways and at 
different times of the year. Wounds made were of course pro- 
tected from chance contamination from outside sources. 
The cortex and wood were inoculated at varying depths; 
mycelium and spores were placed on leaf-scars of different ages 
and between the scales of resting buds. In most cases the 
mycelium from wood block culture was used, but conidia and 
mycelium from agar cultures, ascospores and conidia from 
natural sources were also used. 
It was found in the case of the red currant that the fungus 
made very little progress indeed in the cortex and phloem, or in 
the wood of a healthy branch. When severely wounded by a 
deep incision some headway was made, but in two cases only 
did the fungus establish itself and produce fructifications on 
the branch. 
As a rule a small discoloured area was formed round the 
point of inoculation and this did not increase. Callus formation 
rapidly covered the wound with healthy tissue, and by the 
following year the only trace of the inoculation was a small 
dark area in the wood. 
In the case of the horse-chestnut and lime several branches 
were found in which the fungus made rapid headway, fructifi- 
cations of Nectria being formed in about three months. In 
other cases on the same trees the fungus was apparently isolated 
and unable to make headway. 
The observations on naturally occurring infections suggest 
that the fungus can attack healthy wood when it is established 
in a dead portion adjoining the healthy part. A series of in- 
fections were therefore made on artificially killed branches 
projecting from healthy branches. Some were killed by severe 
longitudinal slitting, others by means of a steam jet or the 
flame of a spirit lamp. All were covered up for some days before 
inoculation. 
The fungus was found to establish itself fairly readily in these 
killed side shoots, stromata being developed sometimes in six 
weeks. After a period which was variable, but never less than 
six months, the fungus began to work its way into the main 
stem, stromata appearing on the side from which the shoot 
projected. In time the whole stem was blocked, exactly the same 
symptoms being observed as have been described previously 
from field observations. 
CONCLUSIONS. 
It would seem probable that this fungus resembles others 
which have been described recently in that it cannot establish 
