POLYMORPHIC FUNGI. 
2D 
damp, discoloured, but not by any means mouldy. At length, 
and rather suddenly, patches of mould, sometimes two or three 
inches in diameter, made their appearance. • These were at 
first of a snowy whiteness, cottony, and dense, just like large 
tufts of cotton wool, of considerable expansion but of miniature 
elevation. They projected from the paper about a quarter of 
an inch. In the course of a few weeks the colour of the tufts 
became less pure, tinged with an ochraceous hue, and re- 
sembling wool rather than cotton, less beautiful to the eye or 
a lens, and more entangled. Soon after this darker patches 
made their appearance, smaller, dark olive, and mixed with, or 
close to, the woolly tufts ; and ultimately similar spots of a 
dendritic character either succeeded the olive patches, or were 
independently formed. Finally little black balls, like small pin- 
heads, or grains of gunpowder, were found scattered about the 
damp spots. All this mouldy forest was more than six months 
under constant observation, and, during this period, was held 
sacred from the disturbing influences of the housemaid’s broom, 
being consigned to the master’s care with little compunction, 
but occasionally it became the subject of remarks not altogether 
flattering either to the wall or the moulds, or the master 
who was protector and patron of such a wretched mess. 
Curiosity prompted us from the first to submit the mouldy 
denizens of the wall to the microscope, and this curiosity was 
increased week by week, on finding that none of the forms 
found vegetating on nearly two square yards of damp wall 
could be recognised as agreeing specifically with any described 
moulds with which we were acquainted. Here was a problem 
to be solved under the most favourable conditions, a forest of 
mould indoors, within a few yards of the fireside, growing quite 
naturally, and all strangers ; could they all be related, or if 
not, why should all of them appear on that wall for the first 
time? Whence could these new forms proceed? Were they 
a new creation? Were they only other conditions of very 
common things ? Certainly here was material for much reflec- 
tion, perhaps some speculation. Some of the problems are 
still unsolved. 
The cottony tufts of white mould which were the first to 
appear had an abundant mycelium, but the erect threads which 
sprung from this were all for some time sterile (PI. LXVIII. fig. 
1) ; they were slender, \<fery delicate, jointed, and branched ; so 
interlaced that it was difficult to trace the threads throughout 
their length, or to separate them from each other. Fertile 
threads were then developed in tufts mixed with the sterile 
threads, or individual fertile threads appeared amongst the 
sterile. These latter were rather shorter and stouter, also 
sparingly branched, but beset throughout nearly their whole 
