148 A. W. BENNETT. 
partition-walls, is especially prevalent when the deve lop- 
ment has been proceeding for a long time on the surface of 
the fluid. An abundant supply of the nutrient fluid appears 
especially conducive to the development of the mycelium ; 
the long-continued action of the air to that of the buds. 
When developed in dilute wine beneath glass, the Myco- 
derma-cells produced beautiful mycelia, which appeared to 
attempt to reach the air. As long as the mycelium con- 
tinued to grow in the fluid it consisted of very long cells 
and branches with but very few buds, while where the 
plant came in contact with the air the cells became shorter, 
the production of septa almost entirely ceased, and the ar- 
borescent form, consisting of unpartitioned buds, displayed 
the greatest perfection. In order to determine still further 
the influence of external conditions on the mycelium of My- 
coderma, some pieces which were not producing buds were 
removed from the sauer-kraut scum to an infusion of carrot 
in which the formation of mould had been prevented. After 
the lapse of about two days the filaments had become di- 
vided by a number of septa into short cells, and buds 
began to develop from the free apex. ‘The filaments even- 
tually broke up more or less completely into fragments at 
the septa, the filaments becoming constricted quite indepen- 
dently of the septa. 
The mycelium of Mycoderma bears so strong a resem- 
blance to Oidium lactis, and to the mycelium of Chalara 
about to be described, as often to be distinguished from them 
only with difficulty ; especially when, as is often the case, 
the three grow intermixed in the same solution. But not- 
withstanding this resemblance, the three organisms are 
essentially distinct, and possess widely different properties. 
The zigzag filaments of the Mycoderm mycelium put out 
buds; from those of Chalara conidia become detached by 
constriction ; the filaments of Oidium develope into hyphe, 
which produce chains of conidia by segmentation. ‘The 
attempts of the writer to cause the latter to produce buds 
or to form conidia by the process of constriction, so charac- 
teristic of Chalara, always failed. 
To sum up the phenomena now described :—Mycoderma 
vini exists in two vegetative conditions; the mycelium, aud 
the budding form. In the first condition the branches are 
the result of lateral outgrowths from the cells, which grow 
uninterruptedly at the apex ; the cells themselves continue to 
grow in length, and become segmented by septa. When the 
mycelium is about to pass over into the budding condition, 
on free access of air, it becomes broken up by numerous 
