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Mr. Ward then proceeded to show how these results of 
experiments and observations in the laboratory were applied 
to explain the course of events on coffee estates. 
Observations demonstrated that spores are blown about 
estates, reach the leaves of the coffee, are washed to the 
edges and lower sides, and there germinate ; that, therefore, 
all the conditions of the artificial infection are brought about 
in nature. Having learnt particulars as to the periods 
of growth of coffee, the time occupied in infection, experi- 
ments, &c., the next step was to ascertain how far the 
changes in climate, &c., account for the rise and fall in the 
“ virulence of the disease” — i.e. in the quantity of leaf- 
destroying fungus present at any time. 
On one of a number of leaves which were carefully watched 
during several months, the first spot became most evident 
in the beginning of June, and on June 3rd was throwing off 
spores. On June 29th there were 35 new spots forming 
spores, and on July 15th appeared 12 others. On July 23rd 
the leaf began to show signs of falling, and it dropped on 
the 26th. In such a case, the successive generations of 
mycelium appeared at such intervals as would be accounted 
for if they arose from spores derived from the first spot. 
No doubt the spores were shaken around, and germinated 
soon after, each becoming the centre of a new spot as 
described. 
In a given district the weather was dry and hot during 
the early period of the year, and from January to March 
there were few leaves on the trees, and little or no moisture 
to bring about the germination of any stray spores on them. 
In April and May the wet growing season commences, many 
new leaves are formed, and the few spores present germinate, 
and produce disease spots in two or three weeks after ; hence, 
by June, there are several “ disease spots,” each of which is 
shedding spores all around at every shake. These spores, 
scattered on the leaves, germinate in the rains which still 
