390 Results of the Competition of 1874, 
In the seventeen other localities the chief manure employed 
was farmyard-dung. This manure might be the medium 
of introducing the disease as the oospores of fungi are re- 
markably indestructible and might resist the destructive 
action of the dunghill, and even pass, without losing their 
vital powers, through the alimentary canal of animals. There 
is, however, no indication in last year's experiments that 
the appearance of the fungus had any connection with farmyard- 
manure. Lincoln, with ten tons per acre, was entirely free 
from disease, and Yorkshire with fifteen tons, and East Lothian 
with twenty-five tons, were but slightly affected, while similar 
quantities were employed in localities which suffered heavily. 
The result of Dr. Voelcker's experiments at Carlisle,* showing 
that the kind of manure had no appreciable influence on the pre- 
sence or extent of the disease, is confirmed by the experiments 
of last year. 
If we divide the twenty localities into two groups, the one 
containing the places where the disease occurred to any appre- 
ciable extent, and the other, those that were more or less com- 
pletely free from it, .it will be observed that they arrange them- 
selves geographically, the first group being all (excepting Perth) 
on the west side of the United Kingdom, while the second are on 
the eastern side. This grouping does not, of course, depend on 
temperature, soil, or method of cultivation, as there is nothing 
in common among the members of each group in regard to these 
points. But the two have each a somewhat close agreement in 
regard to the rainfall, the amount on the western side being 
much greater than on the eastern, consequently this division 
gives us for the eastern stations the smallest amount of disease 
and the least rainfall, and for those on the western side the 
largest amount of disease and the heaviest rainfall. We have 
already seen that as long as the season continued dry the potato 
crops were healthy, and that the disease immediately succeeded 
the heavy rains. There can be no doubt that the ^appearance 
and progress of the disease is intimately connected with the 
amount of moisture present in the atmosphere. Now that the 
fungus {Peronos-pora ivfestans, Mont.) has taken possession of 
our country, its spores abound in our air, and are ready to 
germinate whenever the proper conditions are present. As 
grain docs not grow when stored in the barn, and deprived ol 
moisture, so the spores of this fungus cannot germinate without 
a supply of moisture. They may rest on the surface of the 
leaves of the potato and remain perfectly harmless if the air 
contains no free moisture, for they can obtain none from the 
♦ 'Journal of the Royal Agricultural Society,' vol. xxviii., ji. 51G. 
