Marshall Ward, — On a lily- disease. 381 
later preparations, these infecting tubes are running in the substance of the outer 
walls of the epidermal cells, just beneath the cuticle. Zeiss D, oc. 2. 
Fig. 48. Similar preparation, but the conidium lay in a drop of dilute Pasteur’s 
solution on the epidermis, and has thrown out a long thin hypha outside, in ad- 
dition to the infecting tube below the cuticle. The spore still retained some 
protoplasm. Zeiss E, oc. 4. 
Fig. 49. Similar preparation to the last, but the whole of the protoplasm has 
already passed into the infecting tube, which has become branched and septate. 
This preparation and the last were treated with chloral-hydrate before drawing. 
Zeiss E, oc. 4. 
PLATE XXIV. 
Fig. 50. Preparation showing a not uncommon mode of infection. The spore 
had germinated on the outside of the epidermis, and rapidly produced dense tufts 
of branching hyphae which make their way simultaneously into the tissues : the 
cell- walls around are all gelatinised, and turning brown. The preparation was 
made by cutting off the epidermis with the razor, and viewed from within. If 
seen in section (at right angles to the plane of the figure) the epidermis would be 
found sunk in, and turning brown, this could not be shown in the drawing. 
Zeiss D. 
Fig. 51. Vertical section through a lily-bud with a ‘disease spot’ in the con- 
dition shown in Fig. 2. The epidermis and cuticle, together with underlying cells, 
have collapsed and turned brown : at first sight there are no signs of a fungus 
at this stage, but if such a section is carefully swollen by being treated with very 
dilute ammonia or chloral hydrate, the gelatinised cell- walls are found to have the 
fungus embedded in their substance. Zeiss D. 
Fig. 52. A similar section to the above, but which has been swollen by holding 
it for a minute over an open bottle of ammonia hydrate. It is then seen that the 
walls of the epidermal cells and several subjacent cells are completely gelatinised 
and broken down, and that the fungus-hyphae are rampant in the mucilage. The 
destructive action is also seen to extend for some •distance into the walls of neigh- 
bouring cells, as indicated by the yellow and red-brown hues which the destroyed 
walls assume. Zeiss D. 
Fig. 53. Similar preparation to the last, but the section was taken through the 
pedicel, and the spot was in a slightly less advanced stage. The section was 
observed in water, in which the preparation (cut fresh) was laid : little can be 
made out beyond the fact that the cells are destroyed and the cuticle sunk ; but it 
may be noticed that I had observed and drawn a sort of irregular dark mass, 
looking like a slight thickening of the cuticle about the middle of the depression 
— this was no doubt the collapsed remains of the spore. 
In Fig. 54 the same section is shown after treatment with extremely dilute 
ammonia, and we now see that branched infecting hyphae were all the time em- 
bedded in the contracted mucilage produced by the destruction of the cell-walls : 
moreover, the empty spore which gave rise to these hyphae was still attached, and 
assumed its normal position after swelling in the ammonia. Again, and very 
clearly, it is seen that the destruction is extending into the walls of cells at a dis- 
tance from the hyphae (cf. Fig. 8) : it seems difficult to imagine how this can 
occur otherwise than by the diffusion of a soluble ferment, and investigation 
