PARASITIC ON PELLIA EPIPHYLLA. 109 
the nutrient gelatine contained in them; and it resembled, too, 
that taken from the surface of the host or teased out from its 
tissues, with the exception that the cultivated mycelium had 
more protoplasm, and looked, generally speaking, plumper than 
the normal; but that seemed to me quite what might be ex- 
pected; the occurrence of empty segments was more common, 
too, in the normal than in the cultivated mycelium. In the 
hanging gelatine-drop cultures cross connexions were numerous, 
and in some cases very complex (fizs. 31 & 32); but in no single 
instance did I see anything resembling the formation of Haft- 
organen or “ organs of attachment," so common in similar cultures 
of Botrytis. This method of hanging-drop cultures demonstrated 
especially well the greater luxuriance of the growth in a more 
nutrient medium. Spores were found to grow better in gelatine 
consisting of a cold-water extract of the thallus containing 
gelatine, than in the extract alone, and better still in gelatine 
containing boiling-water extract and which I cail “nutrient 
gelatine.” 
After about three days’ growth the mycelium in these hanging 
gelatine drops shows a special form of branching; the terminal 
hyphe swell, their protoplasm becomes much vacuolated, and 
these hyphe put out a very large number of short thick branches 
Which often give off numerous secondary branches, thus producing 
a complicated branching to which, from its appearance, the name 
“ coralline branching " has been given (fig. 30). In such cases 
the cover-slip, when examiued with the naked eye or simple lens, 
presented exaetly the appearance of some of the tube-cultures in 
an early stage when examined from above. 
One special advantage of hanging-drop cultures is the eluci- 
dation of the formation of the spore-clusters in tube- and flask- 
cultures. After about eight to ten days’ growth there appeared 
on the cover-slip small white patches exactly similar to those of 
the gelatine surface in tubes and flasks. Under the microscope 
nese patches were found to be composed of very numerous aerial 
P branching freely, and radiating outwards from a patch of 
M On in a day or two became too dense to be made 
white and de hyphe and their branches were produced terminal 
and whos more colourless spores, which increased in size 
to one side wt pecame much more distinet. Just beneath and 
increased i 0 t ese terminal conidia appeared others, whieh also 
n size and definiteness of wall (figs. 27, 28,29), and in 
