the same
individual mycelium thread, the evidence would be conclusive. In
default of such conclusive evidence, we are compelled to rest with
assumption until further researches enable us to record the assumption
as fact.[k]

Apropos of this very connection of _Penicillium_ with _Mucor_, a
similar suspicion attaches to an instance noted by a wholly
disinterested observer to this effect. "On a preparation preserved in
a moist chamber, on the third day a white speck was seen on the
surface, consisting of innumerable 'yeast' cells, with some filaments,
branching in all directions. On the fourth day tufts of _Penicillium_,
had developed two varieties--_P. glaucum_ and _P. viride_. This
continued until the ninth day, when a few of the filaments springing
up in the midst of the _Penicillium_ were tipped with a dewdrop-like
dilatation, excessively delicate--a mere distended pellicle. In some
cases they seemed to be derived from the same filament as others
bearing the ordinary branching spores of _Penicillium_, but of this I
could not be positive. This kind of fructification increased rapidly,
and on the fourteenth day spores had undoubtedly developed within the
pellicle, just as had been observed in a previous cultivation,
precisely similar revolving movements being also manifested."[l]
Although we have here another instance of _Mucor_ and _Penicillium_
growing in contact, the evidence is insufficient to warrant more than
a suspicion of their identity, inasmuch as the equally minute spores
of _Mucor_ and _Penicillium_ might have mingled, and each producing
its kind, no relationship whatever have existed between them, except
their development from the same matrix.

Another case of association--for the evidence does not proceed
further--was recorded by us, in which a dark-coloured species of
_Penicillium_ was closely associated with what we now believe to be a
species of _Macrosporium_--but then designated a _Sporidesmium_--and a
minute _Sphaeria_ growing in succession on damp wall-paper. Association
is all that the _facts_ warrant us in calling it.

We cannot forbear alluding to one of the species of _Sphaeria_ to which
Tulasne[m] attributes a variety of forms of fruit, and we do so here
because we think that a circumstance so extraordinary should be
confirmed before it is accepted as absolutely true. This refers to the
common _Sphaeria_ found on herbaceous plants, known as _Sphaeria_
(_Pleospora_) _herbarum_. First of all t