Essed.—The Panama Disease. II. 
357 
one may safely take for granted that the chlamydospores filling some 
pseudo-pycnidia are partly or even entirely derived from conidia. 
Mycocecidia. Under this name mention was made of structures which 
on careful examination proved to be effluxes of pegmatia to the surface of 
the leaves, where the epidermis and subepidermal layers are absorbed. 
As will be seen in Fig. 7, remnants of absorbed tissue are enclosed in these 
mostly dome-shaped bodies, in which air-spaces are found, some of which 
contain chlamydospores in making or fully formed. 
Enzymes. Judging from the histological preparations, there was good 
reason to think that the changes in the protoplasm and the cell-walls were 
caused by the action of an enzymic secretion of the fungus. To make sure, 
some cultures were raised on liquid sterilized banana extract in wide 
tubes. At the end of three weeks they were poured out on a filter and 
the liquid collected. To this absolute alcohol to four times the volume was 
added, when a yellowish precipitate was thrown down, which, collected on 
a filter and dried in the stove at a temperature of 37 0 C., had a weight 
of no mg. Dissolved in 22 grams of water (sterilized), and slices of 
a healthy banana sucker — cut off with the utmost precautions so as to 
secure sterility — being dropped in the solution contained in a large tube, 
which was then shut off with a lump of sterilized cotton-wool, it was 
noticed after three days that the solution became opaque and thickish, 
while the slices were very much swollen. After three more days the 
liquid became slimy, and the slices brought under the microscope (low power) 
showed that parts of the cell-walls were dissolved ; the spiral thickenings 
of the vessels were lying loose, and the hyaline transparency of the proto- 
plasm was seriously disturbed. The aspect was the same as met with in 
the tissues of the diseased plant. The same experiment was repeated with 
the precipitate obtained from a watery extract of the mycelium ground 
down with sterilized sand. The results were identical. From the above- 
mentioned facts one might safely infer that the changes brought about by 
the secretion of the fungus are due most probably to at least two different 
enzymes, of which the one has properties approximating to cytase, if not 
actually cytase, and the other proteolytic qualities (vegetable trypsin). 
The first-mentioned enzyme, in fact, is one displaying the same qualities as 
the cytase of Peziza sclerotiorum described by de Bary — here also mention 
is made of c curious organs of attachment in the shape of a kind of tassel 
which seem to be identical with the haustoria of the fungus described 
above. There was surely good reason to assume the presence of a second 
enzyme with proteolytic qualities ; for an enzyme with such a wide range 
of action, decomposing and gelatinizing the cellulose and pectose of the 
cell-walls and at the same time disintegrating the protoplasmic contents of 
the cells, was hardly conceivable. On the other hand it appeared to me 
very probable that the enzyme causing the disintegration of one or more of 
B b 
