Marshall Ward. — On a lily -disease . 341 
in contact during the conjugation of the hyphae of the cross- 
connections may be cited as evidence that the ferment can 
dissolve its own cell-walls ; moreover, the deliquescence of the 
walls of the organs of attachment (p. 328) points to the 
same conclusion, as also do known phenomena in other 
fungi. 
We may now pass to the description of cultures and 
methods by which I succeeded in observing the actual 
piercing of the cell-walls by the tips of the hyphae of this 
fungus, and then to the subject of the action of aqueous 
extracts of the mycelium on cellulose, since these are the two 
important points to establish in proof of the above conclusions. 
Having found that when slices of the buds or leaves of the 
lily were placed in the culture-drop in which a spore was 
germinating, it was very difficult to avoid the introduction of 
foreign organisms, and that even when bacteria did not spoil 
the culture the products of disorganisation of the chlorophyll- 
corpuscles, etc. obscured the observation, it became necessary 
to adopt some modification of the process : this was success- 
fully accomplished by the following means. 
In the first place I employed glass-slips and covers which 
had been heated to near redness in a porcelain evaporating 
dish, and made the damp chambers of newly sterilised 
bibulous paper : then, taking care that none of the apparatus 
was touched with anything but recently heated forceps, 
needles, and freshly drawn glass capillary tubes, I placed a 
small drop of distilled water in the centre of the cover-slip 1 
by means of a freshly drawn capillary pipette, and sowed one 
spore in the drop. The single spore was obtained as follows. 
The conidiophores under a damp bell-jar usually have a tiny 
dew-drop at their ends, in which are numerous conidia, and 
it is not difficult to lift this off clean, with the point of a 
sterilised needle ; the drop with its contained conidia is then 
placed in a larger drop of pure water, and the drop then 
fished with a clean needle. The needle lifts a small drop, 
1 This is not so easy to do as it may seem, for the surface of the perfectly 
cleaned glass is often so readily wetted, that the drop is apt to spread as a film. 
