480 Brooks. — Observations on the Biology of Botrytis cinerea. 
germination, possessed the power of destroying living tissues. He concluded 
that this power lay in the secretion of some poisonous substance or sub- 
stances by the fungal hyphae, the tissues thus disorganized serving as 
food material for the further development of the fungus. In regard to the 
disintegration of the tissues, De Bary states that two phenomena are to be 
distinguished, viz. the death of the protoplasmic bodies and the destruction 
of the cell-walls. He came to the conclusion that an enzyme is the specific 
agent of the latter, while the death of the protoplasmic bodies might be due 
either to an enzyme or to an acid, or to both working together. 
Marshall Ward, in his work on ‘ A Lily Disease found that a fungus 
nearly related to Botrytis cinerea , or possibly identical with it, attacked 
plants of L ilium candidiim in a very similar manner to that of Sclerotinia 
Sclerotiorum mentioned above. He attributed the disorganization of the 
tissues of the Lily to a cellulose-dissolving enzyme secreted by the fungus. 
He found that the conidia could bring about direct infection of the leaves 
and flower buds, though he noticed that the attack was stronger if some 
saprophytic nourishment was at hand to invigorate the young germ-tubes. 
R. E. Smith, in a recent paper, puts forward the view that some such 
substance as oxalic acid is secreted by the fungus and is responsible 
for the primary destruction of the tissues. 
Kissling, in 1889, published an account of a disease of Gentiana lutea 
caused by Botrytis cinerea. He found that the conidia could not bring 
about direct infection of the leaves, though the young germ-tubes readily 
attacked the stigmas and anthers of the flowers. Doubtless this was on 
account of the lack of cuticularization of these parts. It is noteworthy that 
the species of Sclerotinia which cause the ‘ mummy y fruits of various kinds 
of Vaccinium infect their hosts in the same way. 
In 1899 Nordhausen investigated further the question as to whether 
Botrytis conidia can infect living tissues. He found that non-cuticularized 
organs such as the anthers and petals of the Tulip and Crocus, and Moss 
leaves succumbed readily to the attacks of the germinating conidia. Only 
under such a condition as the following, however, did it result that leaves 
could be attacked. He placed conidia on the leaves of Tradescantia kept 
in a damp chamber, and regulated the deposition of dew. When the 
amount of dew deposited was small, the spores caused infection. He 
explained this, and the non-infection when the deposition of dew was 
greater, by supposing that in the latter case the poisonous substance 
secreted by the germ-tubes was diluted beyond the minimum intensity 
necessary to cause infection. Nordhausen mentions a number of factors 
in regard to the disposition of the host which might render it liable to 
destruction by Botrytis. He suggests that plants which have become 
etiolated through being kept in darkness would succumb the more readily 
to the fungus ; also that dying leaves of ordinary plants would offer less 
