376 Howard . — On some Diseases of the 
In my first paper ( 17 ) on this subject an experiment is 
described in which pieces of healthy unsterilized cane were 
split open and infected with Melanconium spores, and with 
mycelium developed from a pure culture, and in which micro- 
and macro-conidia developed five days afterwards. On this 
occasion the control canes showed no such spore-formation. 
On repeating this experiment several times, however, it was 
found that micro- and macro-conidia occurred as frequently 
on the control canes as on those infected with Melanconium 
mycelium and spores, so that no proof of a genetic connexion 
between these forms, Melanconium and the macro- and micro- 
conidia, can be obtained from the experiment above referred 
to. Indeed, unless it can be shown that macro- and micro- 
conidia are developed in sterilized media from a single Melan- 
conium spore or its mycelium, these forms must be regarded 
as two different Fungi. 
During the progress of this investigation it appeared interest- 
ing to determine what happens if flask-cultures of Melanconium 
spores are made in which macro- and micro-conidia are at 
the same time intentionally introduced. 
Four sterilized flasks, containing the sugar-cane extract 
food-material mentioned above, were infected as follows (i) 
with spores obtained from a single-spore hanging-drop culture 
of Melanconium , (2) and (3) with similar Melanconium spores 
to which had been added macro- and micro-conidia from 
a single-spore hanging-drop culture, and (4) with similar 
macro- and micro-conidia only. The result was interesting. 
In two days the liquid in (2), (3), and (4) was filled with 
colourless mycelium while nothing could be detected in (1). 
In three days, macro- and micro-conidia, exactly like those 
started with, were developed in (2), (3), and (4), all three 
flasks being identical in appearance. On examining (2) the 
mycelium showed no traces of fusion of the hyphae, so 
characteristic of Melanconium , but the formation of macro- 
and micro-conidia was extremely abundant. In seven days, 
stromata of Melanconium were evident on the surface of (1), 
but no formation of these bodies was noted in (3), which was 
