84 
CHANGE OF VARIETIES OF SUGAR CANES. 
Has the continual propagation of one variety led to wipe m 
There is no evidence upon this point beyond the impression left b 
circumstances. ‘The production of plants from seeds possesses advan- 
tages of maintaining vitality, of adaptability to surrounding conditions, 
and of wang itself to tos e produ - ion of new qualities. 
Genera ience i i ws, on the one hand, that a 
the most reliable kind to show that iet are several varieti ca 
Barbados (including some seedling canes) which possess a striking 
though not complete immunity to fungoid attac 
The fo owing biological consideration leads to the same view, that 
where one variety of plant is cultivated to the practical exclusion of all 
others, that all the parasites of that plant. per hh the very best conditions 
or their continuous propagation and increase. Or te reduce thi 
enerality to our special case, that continuing to plant the Bourbon cane 
is to provide a continuous supply of material for the rind fungus to 
grow and increase upon. Change the variety, and the parasite exists 
with much greater diffieulty or has to change its habits. 
The fact that both the rmd fungus and the root fungus are so much 
less liable to attack certain varieties of the cane other than Bourbon 
cannot fail to be a fact of immense value. 
ommission after very careful inquiry not x found that 
d 
certain varieties of canes strongly withstand both root and rin 
fungus, but the record also shows that at all events in some places 
ties are very profitable to cultivate, and y /ommission 
ich proves thc fitted for it. During the last few T hie the 
which attack the Bourbon sugar-cane have steadily increased in amount, 
and the history of like cases points to the belief that "this increase will 
go on and not abate until some very serious measures are adopted; and 
amongst them we consider the cultivation of new varieties as one of the 
most promising. With the res prospect as regards price of sugar 
the whole industry can only exist by the tende economy in cultivation 
and manufacture; and with any serious amount of disease, cultivation 
must cease to be profitable. Undoubtedly if the progress o of the riri 
. disease in Barbados eannot be checked, the island is Sor : 
And all considerations ufi to the conclusion that the whole frt 
