66 ODOROGRAPHIA. 
1000 lemons in the factories at Palermo is 320 grammes of oil ; in 
those of Messina, where a better quality of fruit is employed, the 
yield is about 400 grammes. The same number of lemons yield 
about 40 litres (10 gallons) of acid liquor, which, of course, is 
utilized for citric-acid manufacture. 
Trees of the Citrus tribe do not often become diseased, 
but when a disease once manifests itself it spreads with great 
rapidity. The disease of the orange-tree was first discovered in 
the Azores in 1836, when it was found that the oldest and best 
trees, as much as 200 and 300 years old, producing each from 
5000 to 20,000 oranges, were disappearing. It was observed that 
all the trees affected produced a very heavy crop the very year that 
the disease manifested itself, that the leaves became yellow and fell 
in great quantities, and on the trunks near the ground, and some- 
times beneath the ground, the bark opened and drops of a kind of 
yellow gum exuded. The drops resembled tears—lagrimas in 
Portuguese ; therefore the disease was named “ Lagrima.” Many 
orangeries were quite destroyed. The disease was remedied by 
cutting the bark across, to allow the exudation to run out; and if 
the disease was in a very advanced state the bark and the whole of 
the diseased wood was cut out, the roots being bared to a distance 
of a foot or two from the stem, and every portion of diseased root 
cut away. If the disease was taken at an early stage this process 
was successful. The disease is not the result of age, as there are 
trees in Spain now known to be 600 or 700 years old, and when 
the disease made its appearance in Australia trees of 22 to 
25 years old, and even seedlings of one year old, were attacked. 
A report by the late Dr. Landerer states that millions of lemon- 
trees grow on the islands of the Grecian Archipelago, on Chios, 
Paros, and in the Peloponnesus, but that the same disease appeared 
amongst the trees at Paros which had ravaged the plantations of 
Sicily. The methods of extracting the essential oil by the “ éponge” 
and the “ écuelle ” were introduced into Paros by the Sicilians. 
The oils from the peel or “ zeste ” of the citrine fruits are manu- 
factured in large quantities in the north of Italy and in the 
south of France, the fruit beg taken when in a barely ripe 
state—the oil of the Bitter orange being by far more valuable 
than that of the Sweet. They are extracted by processes called 
the “Eponge” and the “Ecuelle-a-piquer,” and are termed 
“ Essence de Bigarade au Zeste” and “ Essence de Portugal au 
