THE COFFEE-LEAF DISEASE OF CEYLON. 125 
fication is apparently to enable the Hemileia to bridge over 
the dry season, the sporidia immediately germinating on the 
approach of wet weather. 
Mr, Morris, from whose forthcoming handbook most of the 
facts put together in the preceding sketch are taken, was 
during the greater part of last year placed on special duty 
for the purpose of coffee-leaf disease inquiry. He was of 
course extremely anxious to discover some vulnerable point in 
the life-cycle of the Hemileia at which it would be open to 
attack. It is to his persevering investigations that we owe 
the clear account of its habits which we now possess. Mr. 
Morris recommends that during the period of external 
development, when the mycelium is merely mechanically 
attached, as it were, to the surface of the coffee tree, it 
should be treated with some remedy which will destroy its 
vitality without injuring the coffee tree itself. It is not 
necessary in the present paper to discuss the attempts and 
experiments which have been made in this direction, more 
especially as Mr. Morris will discuss them in his forth- 
coming publication. But as far as can be judged from 
experiments on a small scale the destruction of the filaments 
can be completely effected by dusting the whole coffee plant 
with a mixture of one part of sublimed sulphur and two parts 
of lime ; the effects are very well shown in Plates XIII and 
XIV, the former of which shows the epidermis of a branch, 
and the latter that of the under side of a leaf traversed by 
Hemileia mycelium, both before and after treatment with 
the mixture. Mr. Morris having been transferred by the 
Colonial Office from his post as Assistant Director of the 
Royal Botanical Gardens, Peradeniya, Ceylon, to the Direc- 
torship of the Botanical Department of the Island of 
Jamaica, Mr. H. Marshall Ward has proceeded to Ceylon 
to take up the inquiry where Mr. Morris left it. There are, 
of course, wide practical differences between the conditions 
of a laboratory experiment and the treatment of a planta- 
tion. But whatever is the ultimate result, to Mr. Morris 
belongs the credit of having applied a strictly scientific 
method of investigation to the problem of coffee-leaf disease, 
and of having devised the only method of treatment which 
so far affords any rational hope of success. 
It is only fair to observe that Dr. Thwaites, the distin- 
guished late Director of the Peradeniya Gardens, whose 
opinions must carry great authority, hesitates in accepting 
Mr. Morris’s results. He does not, indeed, gainsay them, but 
he apparently thinks that the account of the life-history of 
the Hemileia given by Mr. Morris is incomplete, and that the 
