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can the fungus come from the following year after a rest of nine 
months ? Montagne and Berkeley have referred at some length 
to a body (dubious to us) found in spent potatoes, and de- 
scribed many years ago as a second form of fruit of Peronospora 
infestans , under the name of Artotrogus. This may even- 
tually prove to be a second form of fruit of our plant ; but 
though Montagne undoubtedly found something which he sent 
to Berkeley, he probably never met with it again, and we 
believe no observer has ever met with a trace of it since. At 
the time of its first observation and description great attention 
was directed to Peronospora , to the consequent neglect of all 
the other members of the vast fungoid army common enough 
on spent potatoes ; and this is the reason, we imagine, why 
Artotrogus was referred to Peronospora ; for it might, with 
equal reason, have been referred to a large number of other 
species belonging to very diverse genera, judging from the 
number of Mucedines , &c., common upon decaying potatoes. 
We cannot help thinking that undue importance has been 
given to the non-discovery of oospores in Peronospora infestans , 
by some recent writers, who have said that their ultimate 
discovery might help us to doctor our potatoes in winter, and 
;SO get rid of the disease : it certainly seems strange that at 
-present we know so little of the winter life of this mould after 
-such unceasing search has been made by so many sharp students 
for such a number of years ; but it is doubtful whether any amount 
of doctoring will kill the disease without destroying the potatoes, 
even if oospores or sclerotia are ultimately discovered. Many 
observers have noted the small number (sometimes entire absence) 
of mycelial threads in the cellular tissue of diseased potatoes, so 
that it recently became an interesting fact to observe a dense my- 
celium permeating the earth in the neighbourhood of diseased 
potatoes in some experiments conducted by us. Unfortunately, 
however, mycelial threads do not generally present marked 
distinctive characters, so that it would be impossible to refer 
these threads to Peronospora in preference to any of the other 
moulds, &c., common upon bulbs and tubers. The results of 
our experiments seemed, however, to point to the necessity of 
examining carefully the earth from which diseased potatoes are 
taken. The habits of mycelium whilst in a highly condensed 
state are better known amongst the higher fungi ; and, as an in- 
teresting instance in point, we may mention a case which came 
under our own observation last autumn in regard to Typhula 
phacorrhiza , Fr., which plant is said generally to spring from 
a sclerotium, and of which Berkeley says, in his “ Introduction 
to Cryptogamic Botany,” that it grows indiscriminately on 
Sclerotium complanatum , and S. scutellatum ; and that it is 
not improbable that both are contracted states of the Typhula , 
