382 
Marshall Ward. — On a lily-disease. 
shows that this explanation is no doubt the correct one. It will be noticed that 
the cuticle is not dissolved. Zeiss D. 
Fig. 55. Part of a section through a lily-bud (perianth), on which the conidia 
had been allowed to germinate for three days, and which was thereby infected, 
as shown in Figs. 46-49. The section was cut from a bud which, after infection 
as said, was hardened in picro-nigrosin, and then absolute alcohol : it was then 
laid in glycerine, and held for a minute over the ammonia bottle. The left-hand 
guard-cell of the stoma and the whole of the section on the left were intact ; but 
the five epidermis cells to the right of the stoma had collapsed under the pressure 
exerted by their gelatinised cell-walls, in the substance of which the hyphae are 
running. Further to the right, again, the cells are intact. The swelling action 
of the hyphae is beautifully seen in the walls below the right-hand guard-cell. The 
swollen cell-walls in such sections still give a faint blue with chlor-zinc-iodine. 
Zeiss E, oc. 4. 
Fig. 56. Part of a similar preparation, perhaps slightly less advanced. All the 
essential features are as before. Zeiss E, oc. 4. 
Fig. 57 . Two stages showing the piercing of a cell-wall by the tip of a hypha. 
From a mycelium which had been growing for four days in a hanging drop, con- 
taining a minute section of a piece of lily-bulb. The hypha was observed to meet 
the cell- wall nearly at right angles : contact was established at 4.35, as seen in a. 
At 4.45, as seen in b, the tip of the hypha had dissolved a minute hole through the 
wall, passed through, and bulged out to its normal size on the opposite side. 
Zeiss D. 
Fig. 58. Another case of the same kind, observed on Aug. 4. At 2.55 p.m. 
the hypha, which had traversed a drop of culture fluid (water containing a piece of 
lily-bulb), came vertically in contact with a cell-wall ( a ). The hypha was grow- 
ing rapidly, and in three minutes its tip was seen to be deflected slightly (£ = 2.58 
p.m.): this deflection increased — c was drawn at 3.0 p.m., and d at 3.2 p.m. At 
3.7 p.m., the tip had obviously sunk into the substance of the cell-wall, which was 
swelling at the point of contact (e ) : the swelling of the wall and the sinking in of 
the tip of the hypha increased, and at 3.15 the tip of the hypha was nearly through, 
as shown at f At 3.24 (g) a minute, bright, drop-like protuberance was being 
put forth on the other side of the cell-wall : this was a bud-like outgrowth con- 
tinuing the onward growth of the hypha, as seen at h (3.28 p.m.) and i (3.30). 
All Zeiss D, oc. 4. 
Fig. 59- Piece of thin transverse section of pedicel of lily after lying six 
hours in boiled extract from the fungus : the extract was made by pounding in 
a mortar a flask culture (in Pasteur’s solution) of the fungus, with a little distilled 
water. Zeiss D. 
Fig. 60. A similar preparation, but which had lain for six hours in the unboiled 
extract from the fungus. Even after one hour, the cell walls were observed to be 
swollen, and in six hours they were rapidly becoming disorganised : they still gave 
the blue reaction with chlor-zinc-iodine. Zeiss D. 
