1914) 
COOLEY—SCLEROTINIA CINEREA 297 
by which it is demonstrated that cytase diffuses in agar consid- 
erably beyond the region of hyphal penetration, and that a 
portion of the agar containing the enzyme dissolves cellulose in 
a manner similar to that of the fungus itself. 
The organism employed in my work was isolated from an 
infected plum twig, at Madison, Wisconsin. The original cul- 
tures were taken from a single colony in a Petri dish, this pro- 
cedure giving reasonable assurance that I was working with 
a single strain of the organism. Regarding the systematic 
relations of this organism a word may not be out of place here, 
since considerable confusion has arisen in the literature regarding 
the specific name of the organism causing the brown rot of 
stone fruits (27, 53, 37). Woronin (56) has made an important 
contribution designed to establish the systematic position of the 
two species Sclerotinia cinerea and S. fructigena. It has gener- 
ally been held that S. fructigena causes the brown rot of stone 
fruits in this country, while in Europe this fungus is found only 
on pome fruits; but Matheny (37) has recently given good evi- 
dence tending to show that it is S. cinerea which causes the 
brown rot of stone fruits both in this country and in Europe. 
EXPERIMENTAL STUDIES 
INFECTION 
Some investigators, as, for instance, Zschokke (57), have held 
that Sclerotinia cinerea is unable to penetrate sound fruit, while 
Smith (45), among others, has held that the fungus rapidly pene- 
trates and infects sound and unwounded fruit (peaches). Casual 
observation in the field would seem to justify the former view, 
for those fruits in contact with other fruits or twigs, and there- 
fore liable to puncture or abrasion, are the ones that are usually 
found infected; indeed, field observations and laboratory exper- 
iments point to the conclusion that infection takes place much 
more readily, especially with immature fruits, when the cuticle 
is broken. One would, therefore, naturally raise the question 
as to whether or not infection can take place when the cuticle is 
unbroken, and if so under what conditions and in what stages 
of the development of the fruit. During the summer of 1913 
