38 E. J. BUTLER. 
All the plants, except one, in the four inoculated pots were dead 
by October 26th. On this date those left were pulled out and 
examined. The number of dead plants in the four pots was 18, 18, 16 
and 19 respectively, several in each pot having been pulled out for 
examination on previous occasions. Most had no surface erowth 
of fungi on the roots, though about one-third showed whitish patch- 
es with single-celled spores on a fine mycelium resembling Cephalos- 
porium. Several were placed in the moist chamber and gave rise 
to Cephalosporium and in some cases also Fusarium after some 
days. None gave perithecia, nor were any observed on any plant, 
whereas those that had wilted in soil taken from pot V of Series V 
developed perithecia of Neocosmospora vasinfecta when similarly 
incubated. This series, therefore, combined with Series VI above, 
showed that the soil of pot V contained a harmless fungus, Neocos- 
mospora vasinfecta, with which it had been inoculated, and a viru- 
lent parasite, the fungus now under consideration, which must 
have entered accidentally either from the pot walls, the seed or the 
air. 
A macroscopic and microscopic examination of the diseased 
roots was carried out. The characters of the wilt and the gross 
appearance of the tissues were found to be exactly similar to those 
of cases of wilt occurring naturally on the Farm. In section the con- 
ditions were just as described in my previous paper on this disease, 
the hyphe being found chiefly in the vessels, where also microconi- 
dia and chlamydospores were observed. As this experiment coin- 
cided in time with the gram inoculations mentioned under Series 
XIII, in which plants inoculated with Neocosmospora (as well as the 
controls of the same series) died, the death being from heat and not 
from Neocosmospora as was proved by the further sowings in the 
same pots later m the year, when the temperature had fallen, a 
comparison was made between the roots in the two cases. In both 
the conditions were sufficiently alike to lead to considerable difficulty 
in distinguishing between them. The gram roots were permeated 
with the hyphe of Neocosmospora which attained their chief 
development in the vessels. On the surface, while still in the soil, 
