112 MR. W. G. P. ELLIS ON A TRICHODERMA 
(333 u) long, in two days; and the result in another instance was 
striking, a spore about the centre of the section having produced 
a branched mycelium with a total length of 640 u, while a spore 
remote from the section had in the same time produced a single 
hypha 7 u long: hence their growth had been arrested by the 
want of food, but the spores themselves had not been killed. A 
similar experiment was tried by feeding similar starved cultures 
with a drop of nutrient gelatine. The result was that in 40 hours 
after the feeding, some spores had put out hyphe 2-3-6-12 and 
30 divisions or 100 u long; some had put out two germ-tubes; 
and some hyphee had two and three branches ; while the cultures 
serving as controls, 7, e. to which no gelatine had been added, 
still had the spores swollen only and no germ-tubes. 
Often in gelatine cultures after some days’ growth I found the 
hyphz becoming much more attenuated and the protoplasm less 
abundant in the segments, this being also a starvation effect. 
I investigated the parasitic phase of this fungus by examining 
the diseased thallus, and by attempting to produce the same 
appearance in healthy thallus brought from a distance and 
showing no trace of the disease. Some such pieces of thallus I 
infected directly with spores taken from the normal spore 
clusters formed on the host, and others with spores from my own 
pure cultures. Details of these experiments will be given later. 
Careful examination of a very large number of sections of the 
thallus showed that the mycelium was intracellular. Though in 
several instances it appeared that hyphe might also be inter- 
cellular, yet, as I saw no sign whatever of any haustoria, T feel 
satisfied that the mycelium is entirely intracellular. The 
mycelium was most abundant in the superficial cells or those 
immediately beneath them, though it was by no means rare in 
the deeper parts of the thallus. In some sections it was very 
abundant in the neighbourhood of the antheridia, but in other 
cases there was no preponderance of mycelium in such regions: 
So very many sections showed hyphe at the base of the rhizoids, 
as to raise the question whether the infection of the host was by 
way of the rhizoids, but I think the balance of evidence is against 
this idea. In several cases hyphz were found within the rhizoid 
passing along towards its tip but not reaching it, and thus 
growing from the thallus up the rhizoid, rather than having come 
from an infecting spore. I even tried to get the direct infection 
of the rhizoids : I mounted small pieces of the thallus bearing 
