Went . — Notes on Sugar-cane Diseases . 597 
Bacteria mentioned above). However, these two figures will 
demonstrate that the mode of formation of the conidia is the 
same as in the agar-cultures. Parts of these have been drawn 
in Figs. 26, 27 and 28, and more highly magnified in Figs. 29, 
30 and 31. It will be easily seen that the dark black spherical 
conidia arise by budding on the top of cells with a very re- 
frangent protoplast, which are inflated somewhat like the 
top of the sporangial filament of Pilobolus . The conidia 
have a size of 16— 14-5 x 13 — 12 \x ; they are often found on 
dead leaves of the cane. Fig. 32 is a chlamydospore formed 
in a culture of a Melanconium-stylospore in a hanging-drop ; 
but these chlamydospores are very rare. 
Melanconium-stylospores were introduced into slits made 
in sound canes ; the mycelium developed in the dead 
cells surrounding the slits, but in no case (I made nine 
experiments) did they attack the healthy tissue of the cane. 
Exactly the same result followed when I used, not the Melan - 
conium- stylospores, but the mycelium or the large black 
conidia. On dead leaves of the cane Melanconmm-stylospoves 
may germinate ; afterwards the black spherical conidia are 
found on the same spot, but healthy leaves are not attacked 
by the fungus. 
Pieces of sugar-cane were sterilized on the outside by 
keeping them for some time in a flame ; they were then divided 
longitudinally with a sterilized knife and put into a sterilized 
glass box. On the cut surface I placed some Melanconium- 
stylospores. Very soon — within a few days — the spot where 
I had placed the stylospores became dark red, and a mycelium 
could be detected with the microscope in the interior of these 
red cells. Of the ten experiments which I made in this 
manner, seven were finally destroyed by Bacteria (a complete 
sterilization of the cane being almost impossible) ; but in 
three cases the mycelium developed through the cane as this 
was dying and gave rise on the surface under the epidermis to 
the pycnidia of Melanconium ; but the stylospores were smaller 
in size than those which I gathered in the field, though on 
the other hand they germinated much more easily. 
