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W. B. Mercer, 
c) Some of the spores produce straight germ tubes which extend 
normally for a time without branching, and then their terminal cells divide, 
darken and thicken to form either gemma-like groups of cells, or pear- 
shaped conidia (Fig. 5 , ig). 
d) Some divide to form a gemma-like group of cells from which a 
thin straggling, usually unbranched liypha proceeds (Fig. 5 , 20 — 22). 
e) Sometimes a few adhering to the cover glass or remaining sus¬ 
pended in the body of the drop undergo no change beyond very slow 
swelling and darkening. 
f) Finally a few spores lying on the edge of the drop germinate 
normally and give rise to mycelium on which pycnidia may be formed. 
The formation of short bridges between adjaient spores, and between the 
germ tubes of neighbouring spores is characteristic (Fig. 5 , 23, 24). 
Occasionally the germ tubes unite at their tips (Fig. 5 , 24). 
In all cases numerous oil drops are developed, whether in the 
gemmae or conidia — in which case they are both large and numerous 
— or in the mycelium. 
While these changes are going on, the free surface of the hanging 
drop develops a skin which, at first pale straw colour and delicate, 
becomes eventually yellow-brown and tough. After about three weeks it 
is impossible to get the spores out separately with a needle; when this 
is attempted a piece of the skin with spores embedded in it is brought 
away. Around each developing spore, the skin is especially dark coloured, 
the colour being densest in the immediate proximity of the spore. 
Similar results were obtained with Cane Sugar solutions varying 
in concentration from 40 % to 0 , 5 %» with varions strengths of Grape 
Sugar solution, with tap water, and with plum agar drops, provided a 
great mass of spores was used for inoculation in each case. The food 
medium does, however, exert some influence, for spores germinated nor¬ 
mally on drops of very strong potato decoction gelatine; but when the 
medium was diluted with three or four times its volume of water many of 
the spores developed as in Cane Sugar solution. 
The “spore gemmae“ and “spore conidia“ germinate readily when 
brought on to agar (Fig. 5 , 23—30). 
Proceeding now to the examination of spores extruded from pyc¬ 
nidia in normal agar cultures, precisely similar modifications are to be 
found. In this case, however, the changes take place much more slowly. 
Whereas in the sugar drop solution all the various growths detailed are 
to be met with in the course of a fortnight or three weeks, in normal 
cultures the first changes in the extruded spores are apparent .only after 
this length of time. 
The masses of spores then begin to assume a yellowish colour, and, 
passing through yellow-brown become finally black. At the same time 
numerous chains of dark pear-shaped conidia arise from them, radiating 
in all directions, giving the culture a remarkable appearance (Fig. 5 , 31). 
When the masses are sectioned it is found that only a comparatively 
small percentage of the spores are markedly altered. The majority have 
swollen to two or three times their original size, and assumed a smoky 
colour, while a few have behaved like the spores in sugar solution. 
Spores remaining in the pycnidia behave similarly with age. 
