382 
is estimated by the German Consul General, P. Freudenberg, at about 
ten million pounds sterling. This disease also occurs in Java, but its 
ravages there have been partly offset by the introduction of a more 
resistant species of coffee, Coffea liberica from West Africa, which also 
yields more fruit and endures the hot Javan climate very well, even 
down to the coast. 
Both in India and Java variegated plants are common and are used 
for ornamental purposes so extensively as to form a characteristic and 
striking feature of the garden landscape. —Erwin E. Smith. 
Mayer, Adolf.— Ueber die Mosaikkrankheit des Tabaks.* <Landw. 
Ver. Stat., vol. xxxn. Berlin, 1886, pp. 451-467, pi. 1. 
Tobacco plants in parts of Holland are subject to a variegated leaf 
disease. This is sometimes so serious as to take the whole crop, but 
ordinarily only scattered plants in the held are affected and there is 
no indication of infection from plant to plant, although sometimes sev¬ 
eral affected plants may be together. 
' The disease generally appears three to hve weeks after the plants 
have been set out, when they are well rooted and have begun to 
grow vigorously. The hrst symptom is a geographic or mosaic coloring 
of the leaf surface, light and dark green, but otherwise the leaf appears 
sound. Soon with assistance, and a little later to the naked eye a consid¬ 
erable number of thickenings are visible in the green spots. These green 
spots grow so much more than the pale places that there are numerous 
irregular bendings of the leaf surface. Finally the light parts die early. 
The dark parts of the leaves also take on in later stages of the disease 
a transparent and lac-colored shade. When a single leaf is attacked 
all the younger leaves are sure to be, but at first only show earlier 
stages. The injuries caused by the disease are: 
(1) Limitation of growth and a smaller harvest in consequence. 
(2) Curling (wrinkling) of the leaves and unsuitability for cigar 
manufacture. 
(3) Brittleness with the same result. 
(4) Imperfect ripening and therefore incomplete ( schlechter) burn¬ 
ing, also injury of the aroma, so far as this can be said of any Euro¬ 
pean tobacco. Once only the author found a little of the disease at 
Karlsruhe, in south Germany. The growers call the disease bunt, 
rust, and smut. The name “ mosaic disease” was given by Dr. 
Mayer. 
Dr. Mayer undertook a prolonged investigation to determine the cause 
of this disease. The opinions of practical men as to the cause were 
extremely diverse. The attention of the experiment station (Ryksproef 
*This paper appeared some years ago, but seems to have been generally overlooked 
by botanists, owing to its place of publication. The subject is one of much interest 
and it is believed that readers of the Journal will be glad of an abstract. A recent 
lettei Horn Dr. Mayer states that no microorganism has yet been isolated from the 
affected plants. 
