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Peronospora than P. infestans known to grow upon the Potato plant, it is clear 
that the resting-spores cannot rationally be referred to any other than the Potato 
fungus. Added to this I last year saw the secondary bodies clearly growing from 
the Peronospora threads. I attach great importance to the jointed threads, because 
De Bary, when he figures Artotrogus from ‘‘Montagne’s original specimen ” 
(Researches, p. 258), shows the threads with many septa. From the first I have 
said that Montagne’s Artotrogus and the bodies discovered by me are the same. 
That both belong to Peronospora the sequel will prove. 
It was of the highest importance that these resting-spores should be pre 
served alive till the time arrived for their renewed activity, and with this purpose 
in view I preserved the material in which the resting-spores were present in sealed 
bottles, each bottle containing more or less pure water or expressed juice of horse- 
dung diluted with water. As I was quite in the dark as to the habit of these 
resting spores, of course I did not know what to do for the best, or what the result 
of my experiments would be. These resting-spores at first floated on the surface 
of the water, at length deposited themselves in the sediment at the bottom, and 
on opening one of the bottles the resting-spores are found still intact and apparently 
alive. Happily for me, nearly all my spores retained their vitality. Mr. Broome, 
being equally uncertain with myself, trusted to chance, and chanceso far favoured 
him that all his resting-spores in the slanting saucer of water well retained their 
life. It might have been (and even was) said that possibly some fungus foreign 
to the Potato fungus had got into my material, but if so it must be regarded as a 
coincidence in the highest degree extraordinary that Mr. Broome should also get 
the same new and foreign fungus in his Peronospora material ; a body so puzzling 
in its nature as to be referred to no less than eight different species of fungi. 
All who have studied the habits of the lower fungi know the extreme diffi- 
culty of preserving the specimens alive. This difficulty almost amounts to an 
impossibility. The fungi under study may be present one day and all gone the 
next; a few drops of extra moisture or a slight current of dry air is sufficient to 
destroy or collapse the fwhole lot. Besides this myriads of other parasitic fungi, 
and whole tribes of infusoria commonly make their appearance and prey upon the 
material that is desired to be preserved. 
Now one of the most extraordinary facts about the recent Potato investiga- 
tions in this country is this. These other fungi and infusoria have not to any 
damaging extent appeared. Since I opened my sealed bottles in April I have 
kept the material under a bell-glass, and there has been no offensive odour, and to 
no appreciable extent have there been any moulds, intusoria or parasites except 
Peronospora infestans itself, and the other fungus which is equally destructive to 
Potatos and known under Fusisporium Solani. In investigating the Potato disease 
it was almost as important to discover the entire life-history of the Fusisporium as 
the Peronospora, and fortunately the materials preserved gave a perfect clue to 
the entire life-history of both. Mr. Broome’s material has in the same manner 
been free from an excessive number of other fungi and infusoria, 
