26 THE NORTHERN MICROSCOPIST. 
If it be an animal, it should be observed from the period of its birth 
through several successive generations; if a plant, it is usually 
much more completely under control, and should be watched more 
narrowly than in the former instance, from the germination of the 
seed or spore, until the same form from which it sprung has been 
produced again. Even this amount of watching is not enough ; 
low forms of life are often troubled with what we have been pleased 
to call “alternation of generations,” and so at times we are apt to 
think we have a new and distinct animal or plant, when in reality 
it is only another phase in the life-history of some well-known form. 
We cannot all go easily to ponds and ditches, and neither can 
we all spare that amount of time necessary for the performance of 
insect dissections, and therefore we indicate a path for students in 
which good work may be done by the aid of but little and easily 
improvised apparatus. A few corks, pieces of wood, and thin 
glass covers produce all that is required, so that the score of ex- 
pense should not drive longers after original research out of the 
field. 
The subject is Micro-fungi, or rather a few of the common 
moulds and mildews which may be found by the microscopist 
within the precincts of his own castle, if the circumstances of mois- 
ture and other atmospheric influences have been favorable. The 
members of this branch of Cryptogams are singularly persistent ; it 
is true that the mycelium or vegetative system is often extremely 
evanescent, but the spore or fruit from which the species is repro- 
duced often lies dormant for years, reproducing its kind again when 
_ surrounding circumstances favor its vegetation. 
If the reader refers to Plate II., which appears as the Frontis- 
piece to this number, he will find delineated there various micro- 
fungi which form the subject of this article. . 
First, we will take the order of Mucedines. The plant shown at 
¢c.is the Fenicillum sitophilum, formerly called O:dium aurantiacum. 
This fungus has proved a stumbling block to many pseudo-mycol- 
ogists ; only a few weeks ago we saw in a work by M. M. Chevallier 
and Baudrimont (Food and its Falsifications) the Eurotium fruit of 
Aspergillus glaucus figured as O. aurantiacum, though it could be 
seen at a glance that the fungus illustrated exhibited not a single 
characteristic of the Ozdium genus. 
It must not be supposed that there is no such fungus as Ozdium. 
In 1871, Mr. E. Brown discovered a species on spent hops at 
Burton-on-Trent, to which Dr. Cooke gave the name Ozdium 
aurantium. It forms dense bright orange tufts, sometimes several 
inches in length ; the hyphasma is creeping, branched and septate, 
surmounted by simple or branched moniliform threads, which break 
up into sub-globose or elliptical spores. ‘There are many other 
species of Oidium. 
