[Vor. 1 
302 ANNALS OF THE MISSOURI BOTANICAL GARDEN 
and each inoculated with a drop of a very dilute spore suspen- 
sion containing two or three spores per drop. Тһе progress 
of the fungus and the condition of the host cells were noted 
from day to day but no visible disintegration of the cell walls 
could be observed, nor did the fungus show any particular 
affinity for the middle lamelle. 
Conclusions.—We would conclude, therefore, as a result of 
direct observation on the host tissue, that the fungus penetrates 
the host very readily and rapidly, that it does not necessarily 
follow the middle lamelle in the plum and the peach, and that 
there is no visible general disintegrating action on the middle 
lamell: or on the cell walls of the living host. 
ACTION OF THE FUNGUS ON THE LIVING HOST CELLS 
А significant fact in the metabolism of the brown-rot fungus 
is that it induces such an exceedingly rapid decay in the infected 
fruits. This rapid decay might be connected both with a 
rapid growth of the fungus and with a pronounced power which 
the organism possesses of breaking down and changing the 
constituents of the host. Moreover, several representatives of 
the genus Sclerotinia have been reported to have the power of 
secreting an enzyme or some other substance which kills the 
host cells in advance of penetration. Were this the case, it 
would be expected that rapid decay would accompany the action 
of the parasite. Is this view applicable to the action of Sclero- 
tinia cinerea? Тһе investigators who have made a study of 
this organism differ very widely in their views regarding the 
effect which it has on the host tissues, and it seemed desirable, 
therefore, to determine the relation of hyphal penetration to 
the death of the cells. 
Methods and Resulls.—In order to fix the material for this 
study, it was found satisfactory to proceed as follows: Small 
pieces of the host tissue were taken from the margin of the dis- 
eased area and placed in 95 per cent alcohol for a short time. 
Free-hand sections were made of this material so as to include 
both diseased and healthy cells, and the sections stained for a 
short time in eosin and subsequently decolorized in part with 
alcohol, if necessary to give the desired contrast. Ву this 
Мей 
