108 MR. W. G. P. ELLIS ON A TRICHODERMA 
cultures, described in his paper on “ Ginger-Beer Plant " (Phil. 
Trans, 1892). 
In a similar way spores were allowed to germinate in hanging- 
drops of water containing a small piece of Pellia thallus; those | 
pieces being selected which were small and narrow and had 
rhizoids, being in faet the rejuvenation-shoots referred to lateron 
(p. 116). The time required for germination varied considerably. 
In 65 hours after sowing some of the spores had undergone no 
recognizable change, others had swollen to double their diameter, 
and some had put out a germ-tube equal in length to the dia- 
meter of the swollen spore (figs. 9-12). And between these 
extremes all stages might be found in these cover-slip hanging- 
drop cultures, in which an extract of the thallus was the culture 
medium used. In nutrient gelatine the resulting hyphe were 
much more luxuriant in 42 hours than in the 65 hours above 
In one ease spores had in nutrient gelatine put out tubes in 19 
hours equal in length to twice the diameter of the spore; andin 
yet another (Thursday, June 25th) spores had germinated and 
protruded hyphe in 16 hours with a length of four times the dir 
meter of the swollen spore ; this being the most rapid germination 
observed. In some hanging-drop cultures in which water wa 
the medium used, as much as four days elapsed before the spore 
bad swollen, and in some of these, germ-tubes were put out onlf 
after four days more. 
It was most interesting to watch the formation of the mycelium 
in hanging-drops, or perhaps I might call them hanging-films, 
of gelatine. The germ-hypha or hyphe branched repeatedly, 
septa being put in at more or less regular intervals ; and the 
vacuolation of the protoplasm could be easily followed out. ih 
my eyepiece I used a scale each division of which equalled 335 
and I watehed and estimated the rate of growth of the byph 
the occurrence of the septa and branches, and other interesting 
points connected with the formation of the mycelium. Thus 0 
DEC diiit 
Monday, June 1st, I found a hypha 280 divisions long as à result | 
of 36 hours’ growth, and bearing several branches: I watch 
its tip for some time, and found it to grow at the rate of on? 
division, i. e. 3'3 u, in each minute from 7.18 a.m. to 7.46 4% 
with three exceptions, when it occupied 14 minutes. The 
mycelium, the formation of which could be actually watched 0 
these hanging-drops, resembled exactly that obtained by opens 
gelatine tubes and flasks, and mounting the mycelium growing? 
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