a Fungus causing a Disease of the Sugar-cane. 525 
a very young leaf ; in five days the infected area became 
deep red, and in fourteen days a dense pile of conidiophores 
appeared on the surface bearing microconidia ; hyphae were 
abundant in the tissues, but internal macroconidia were not 
formed. Other experiments proved that the conidia were 
developed much earlier when the surface was first washed 
with soap and water. No inoculation took place when conidia 
were sown on full grown but still vigorous leaves. 
Microscopic examination showed that the germ-tubes of 
the conidia pierced the cuticle of the young leaf, and did not 
enter through the stomata. 
Expt. II. A lateral shoot was broken off close to the stem 
and conidia sown on the broken surface. In fourteen days 
the wounded surface was covered with microconidia, but 
although hyphae had penetrated for some distance into the 
main stem, no macroconidia were present. 
Expt. III. A notch two inches long was cut into a stout 
cane near the base, and a quantity of the interior of the cane 
cut out, making a large cavity into which two conidia lying 
on a cover-glass were placed, the cover-glass being rubbed 
against the wounded surface of the cane to insure the contact 
of the conidia. The external slit was closed up by tying lead- 
foil round the stem. In twenty-two days the broken internal 
surface presented a bright red coloration, and an abundance 
of mature chains of macroconidia were present in the wounded 
portion of the tissue. This experiment, along with others, 
proves that macroconidia are only formed in the interior of 
a cane, and when the tissue is disorganized (Fig. 6). 
Expt. IV. Conidia were sown on the ragged portion of 
a leaf-base close to the main stem, and a thin slice of the 
surface of the cane was cut away half-an-inch above the point 
of infection. In nineteen days microconidia appeared on the 
surface of the wounded portion, clearly proving that infection 
can take place by conidia falling on dead portions that are 
still in contact with the living cane, as leaf-bases, broken 
roots, lateral branches, &c. ; and as these organs originate 
close to the nodes, the points where the disease first shows 
