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POPULAR SCIENCE REVIEW. 
the costs and risks of the venture being so much increased, a 
corresponding increase in price will he a natural result. We 
have the experience of the vine and potato diseases, and more 
recently of the hollyhock disease, to warn us how surely and 
speedily the area of infection is extended, and though for the 
present some coffee-producing countries are free, one or other 
of the pests may at any time make its appearance where it has 
never been known before. 
DESCRIPTION OF PLATE CXXXV. 
a. Portion of leaf affected with “ black rot.” 
b. Fragment of pellicle formed by the fungus PeUicularia kolei'oga x 500 
diam., showing threads and spores. 
c. Small portion of thread further magnified, with young and mature 
spore. 
d. Portion of leaf affected with Hemileia vastab'ix. 
e. Tufts of spores as they appear clustered on the spots, slightly mag- 
nified. i 
f. Young threads and spores x 500 diam. 
g. Mature spores of Hemileia vastatrix x 500 diam. 
h. Globose bodies, or warts, from the surface of mature spores of 
Hemileia x 500 diam. 
