39 & Howard . — ( 9/2 some Diseases of the 
the mycelium referred to was the cause of the non-develop- 
ment of the majority of the roots, and therefore of the root 
disease under consideration. Since Cercospora vaginae and 
the sclerotia fungus do not always occur on the diseased 
canes, but give rise to separate diseases, and moreover as 
their mycelium does not exhibit clamp-connexions, these 
fungi could be left out of consideration until the part played 
by the apparently basidiomycetous mycelium had been 
investigated. Steps were therefore taken to obtain pure 
cultures of the toadstool spores and of the white mycelium, 
and also to perform inoculation experiments therewith on 
healthy canes. 
2. Cause of the Disease. 
Spores were obtained by placing fresh toadstools in steri- 
lized glass dishes with grooved covers. In a few hours a 
white spore print appeared on the floor of the chamber, 
the spores of which were employed in making hanging-drop 
cultures. 
In the cane-extract food- material given above the spores 
germinated in ninety minutes, sending out a narrow germ- 
tube, which quickly branched and into which the contents 
of the spore passed. The earlier stages in the process are 
shown in Fig. 12. In two days, stellate colonies of colourless, 
branched, septate mycelium developed, the protoplasm of the 
apical ends being brilliant and homogeneous. When three 
days old, the mycelium began to grow down into the air and 
to exhibit abundant fusion of the hyphae. At this point the 
formation of clamp-connexions was first noted. Stages in 
the process, which occupied about an hour, and which agrees 
with that observed by Brefeld ( 1 ) in the case of Coprinus 
stercorarius , are shown in Fig. 13. The development of aerial 
hyphae continued, until a dense tuft of pure white mycelium 
resulted. When about seven days old crystals began to be 
formed at the growing ends of the hyphae, and after twelve 
days some of the filaments deliquesced into a gelatinous- 
looking material, which probably explains the cementing 
