1900 | BOTRYTIS AND SCLEROTINIA 373 
house properly managed as to moisture and temperature, and top dressings 
of manure are avoided, the disease need not be feared. 
Bailey’s illustration shows a typical case of “drop.” If these 
statements are to be believed the condition of affairs in many 
lettuce houses about Boston can but reflect seriously on the skill 
of their owners. The disease is there and in abundance, to all 
appearances the same trouble as described by Humphrey, Gallo- 
way, and Bailey. In some houses it is much worse than in 
others but the fact is undeniable that even in the houses of some 
of the best growers, men who possess a practical knowledge of 
their special crop second to none, the disease is almost unchecked. 
Evidently, therefore, Botrytis vulgaris is a more serious parasite 
than is generally supposed, or else some other organism or agency 
is at work, producing a similar effect. 
The first cases of the disease examined by the writer agreed 
very well with Humphrey’s description. The plants were com- 
pletely collapsed and the stems and bases of the leaves soft and 
rotten. The affected tissue was filled with a vigorous mycelium 
(fig. 51). This mycelium was composed of large, branching, 
septate, hyaline filaments, filled with granular protoplasm, but 
with numerous vacuoles in the older portions. The larger fila- 
ments averaged about 13 in diameter. On the borders of 
affected tissue filaments could be seen advancing (fig. 50). 
When placed in a moist chamber over night, the plants became 
Covered in the affected parts with a vigorous growth of the 
conidial form, Botrytis vulgaris Fr. This growth, to all appear- 
ances, originated directly in the parasitic mycelium which had 
destroyed the plant. The conidiophores developed from the 
interior filaments (figs. 73-17). Fig. 18 shows the development 
of the branches, and figs. z and 2 represent a typical conidio- 
Phore of this species. The peculiar branching forms known as 
“organs of attachment” (figs. 19-26) were also abundantly 
Produced from the mycelium on affected plants and in cultures, 
which could readily be made on prune juice, prune bread, prune 
gelatine or agar, boiled fruits or vegetables, oF almost any 
Nutrient substance. Contrary to Humphrey's results, sclerotia 
