184 FUNGI. 
able. Therefore another method of examination was adopted ; 
the spores of a certain form were sown, and sooner or later they 
were looked after to see what the seed had produced—not every 
single spore—but the seed en masse, that is, in other words, 
what had grown on that place where the seed had been sown. 
As far as it relates to those forms which are so widely spread, 
and above all grow in conjunction with one another—and that 
is always the case in the specimens of which we speak—we can 
never be sure that the spores of the form which we mean to test 
are not mingled with those of another species. He who has 
made an attentive and minute examination of this kind knows 
that we may be sure to find sucha mixture, and that such an 
one was there can be afterwards decidedly proved. From the 
seed which is sown, these spores, for which the substratum was 
most suitable, will more easily germinate, and their development 
will follow the more quickly. The favoured germs will suppress 
the less favoured, and grow up at their expense. The same 
relation exists between them as between the seeds, germs, and 
seedlings of a sown summer plant, and the seeds which have 
been undesignedly sown with it, only in a still more striking 
manner, in consequence of the relatively quick devclopment of 
the mildew fungus. 
Therefore, that from the latter a decided form, or a mixture of 
several forms, is to be found sown on one spot, is no proof of their 
generic connection with one which has been sown for the purpose 
of experiments ; and the matter will only be more confused if we 
call imagination to our aid, and place the forms which are found 
near one another, according to a real or fancied resemblance, in a 
certain series of development. All those statements on the sphere 
of form and connection, which have for their basis such a snper- 
ficial work, and are not based on the clear exposition of the con- 
tinuity of development, as by the origin of the connection of the 
Mucor with Penicillium, Oidium lactis and Mucor, Oidium and 
Penicillium, are rejected as antounded. 
A source of error, which can also interfere in the last-named 
superficial method of cultivation for experiments, is, viz., that 
heterogeneous unwished-for spores intrude themselves from 
