362 
Supplement to the Tropical A gncuUurist." [Nov. 1, 1901. 
tormed one of the most favourite sherbets. A 
writer says that in tlie neighbourhood of Mount 
Lebanon the land-tax of the peasants is assessed 
according to the mule-loads of mulberry leaves 
their little farms yield, so that the cultivation 
of the tree is directed to favour the growth of tlie 
leaves (for feeding silkworms) at the expense of 
the fruit. Even at the present day the black 
mulberry is known in Greece as St/camenia. 
The Castor-oil cree {Ricinus communis) is the 
gourd ol the Scriptures (Hebrew Kikayar and the 
Kiki of the Greeks). The plant is referred to in 
Jonah iv. 6, ("He had prepared a gourd and 
made it come up over Jonah "), also 7, 9 and 10. 
"Palma Christi " is another old name for the 
Caster-oil plant, which belongs to the order Euphor- 
biacece. The oil is the chief product and is got 
from the seeds, though the refuse cake has also a 
commercial value as a fertilizer. It is said that 
the modern Jews in London use the oil for their 
Sabbath lamps. In China a peculiar fungus called 
Exidia auriculata, used iu soups, grows oa the 
decaying stems of Kicinus. 
AN EXTRAOKDINARY DLSEASB AFFECTING 
ARECANUTS. 
Agricultural Ledger No. 8 of 1901 consists of 
a report on the above subject by Dr. George Watt, 
Reporter on Economic Products to the Govern- 
ment of India. As the arecanut is now being 
cultivated pretty extensively in the Island, the 
information contained in the report should prove 
of much interest to local growers of the so-called 
" betel nut palm," but as it consists of no less 
than 179 pages (illustrated), the reproduction of 
the whole would not be possible in our limited 
space. We, however, make a few extracts 
which will give our readers a fair idea of the 
purport of the report. 
The indications of the disease are first, the 
withering of a few leaflets (pinnae) of one of the 
innermost leaves. In about 8 or 10 days the 
whole leaf is seen to be withered. The next leaf 
to be affected is that immediately outside. In 
20 or 30 days the bud and innermost leaves, 
which still remain green, fall off through the 
decomposition that is set up at the point of their 
union to that of the stem. If a iree be felled just 
before the crown of leaves falls off, it will be found 
to emit an offensive smell — and the bud when it 
falls to the ground of its own accord gives out 
the same smell. It would appear that the older 
trees become first affected, but that eventually 
both old and young suffer alike. 
What is most alarming is that many Indian 
cultivators affirm that the disease even extends 
to coconuts. If this is really so, there is all the 
more leaaou for our planters to be forewarned. 
Dr. Watt states that he has not had a fair oppor- 
tunity of investigating this ' very remarkable and 
alarming disease,' as it had reached its inactive 
stage when he was deputed to examine it. We 
may therefore expect further information of fresh 
reaearch. He, however, suggests that the disease 
is due to a pathological condition known as 
Tyloses, which may be briefly described as the 
destruction of the vascular by means of the fun- 
damental tissue, a condition brought about by 
certain unfavourable climatic conditions. We 
will not here refer to the opinions of various 
Botanical writers (Bolim, Molil, fieess, Sachs) 
as to tne exact nature of Tyloses, but will only 
mention that the observations of Dr. Watt coiu- 
cidi more with the views of Bohm than with 
these of the other writers. 
To briefly explain these views : The Thyllen 
or cells seen within the pitted vessels of tlie xylem 
or wood are produced by a protruding expansion 
(a kind of hernia) of the adjacent (parenchy- 
matous) cell, which penetrates tlie pore and either 
tears through or causes the absorption of the 
primary membrane of the vessel, — the expan- 
sion being supposed to be due to rapid develope- 
ment of fundamental tissue under the conditions 
previously referred to,— and pushing through the 
pores of the pitted vessels as presenting little resis- 
tance they practically fill these vessels. And not 
only are the ve.ssels of the xylem ruptured, but the 
so-called sporules or vesicles soon produce great 
caverns and rapidly effect the complete destruction 
of all the tissues. At this stage fermentive and 
other saprophytic organi>ms find a way into 
the young growing parts, and in a few days the 
terminal bud and all the young leaves emit an 
offensive smell. With the fa'll of the terminal bud 
the destruction extends to the stem, so that in a 
marvellously short time, says Dr. Watt, what 
was a valuable property is converted into a forest 
of dead stems. This disease in arecanuts is said 
to be the first record of this extraordinary sui- 
cidal degeneration having assumed the form of 
a serious malady ; but it must be viewed (as 
Dr. Watt thinks) as far more of the nature of a 
constitutional malady than of an infectious or 
contagious disease. It clearly originates from 
climatic conditions, but, most fortunatelj', con- 
ditions (so far as India is concerned) that do not 
often occur. According to the observations of 
Dr. Watt the sprouting of the cells of the funda- 
mental tissue is to be explained by a pressing 
need for moisture in the young growing terminal 
bud, which impels them to enter the xylem in 
order to absorb the crude sap. With the filling 
of the vessels by sprouting fundamental tissue 
and the consequent interception of circulation, 
the starvation and death of the terminal bud and 
ultimately of the whole palm ensues. 
The above is the theory of Dr. Watt, and the only 
means of averting the disease is, in his opinion, 
more careful cultivation and drainage so as to 
better control the water supply to the growing 
plants. He recommends that the trees should 
be put far enough to admit of the interplanting 
of other trees, preferably leguminous trees which 
would tend to preserve the natural balance in the 
soil that caa hardly help being disturbed by 
planting up forests of arecanuts put 4 to 6 feet 
apart. It was indeed found that where Ery- 
thrina indica (Erabodu) was found growing with 
arecanuts, the liability to disease seemed greatly 
lessened. 
