[Vor. 1 
308 ANNALS OF THE MISSOURI BOTANICAL GARDEN 
well as the three corresponding untreated portions, were used 
in the preparation of cellulose agars, according to the method 
given above. Тһе media were placed іп test tubes of very small 
(8 mm.) diameter, and sterilized. Тһе tubes of melted agar 
were then cooled rapidly in cold water in order to bring about 
the hardening of the agar before the cellulose had had time to 
settle to the bottom of the tubes. 
Tubes of the various cellulose agars were inoculated with 
Sclerotinia cinerea and others with a species of Penicillium, 
which will be designated as P. expansum', isolated from decay- 
ing peaches and apples. Since these two fungi, viz., Sclerotinia 
cinerea and Penicillium expansum, act very differently toward 
the host, a word contrasting their action may not be out of 
place here. Аз a result of inoculating apples, peaches, or pears 
with a pure culture of Sclerotinia the host tissues are promptly 
killed, while the fruits remain practically as firm after complete 
decay as before inoculation. On the other hand, the fruits inocu- 
lated with the Penicillium become very soft and watery, develop- 
ing a pustule or sunken area where the infection took place. 
One may assume, therefore, that the Sclerotinia does not materi- 
ally affect the celluloses and pectic substances that make for the 
firmness of the fruit, while, on the other hand, Penicillium does 
affect these substances, causing the fruit to lose its firm consis- 
tency. Since these two fungi show such entirely different and 
opposing characteristics as regards their effect on the same 
host, it is interesting to compare their action in pure cultures on 
cellulose and pectin-like substances. Such a comparative study 
was made, the results of which are given in table 1. 
Discussion of Results.—The results given in table m indicate 
that both Sclerotinia cinerea and Penicillium expansum exhib- 
ited in general a very slight hydrolytic action when grown on 
cellulose isolated from the plum, there being very slight action 
with both fungi on the soda cellulose and also on the potassium 
chlorate cellulose and no action on the washed plum cellulose. 
On the other hand, both fungi very readily dissolve filter-paper 
` А culture of this organism was sent to Dr. Chas. Thom, who very kindly examined 
it and gave as his opinion that it was P. erpansum, or perhaps a strain of that species. 
The organism in question, when grown on the media employed by Thom, showed 
characters very similar to those of P. expansum, as given by Thom (48). 
