i)BC» 1, 1902.] Stipplment to the "Tropical AgriciUiurist." 
435 
converted into a cash bringing commodity in the 
shnpe of egg?. 
Keep chickens moderately hungry all day, but 
late in the evening give then all the grain they 
will eatup clean, and a little more will not hurt, 
for what they leave at night they will eat next 
morning for an early breakfast, which will keep 
them quiet until they are allowed out. 
Some recognise the importance of supplying 
giit to fowls, whi'e others do not know that such 
a thing is necessary for the fowls' health and 
profit. Without grit the birds will have poor 
digestion, and a yard of hens with poor digestion is 
an unprofitable possession. 
EDIBLE CON VOLT ULACEAE, 
The edible character of many Convolvulaceae is 
noticeable, though they do not constitute a very 
important item of diet. Among the Ipomoeas 
we have 7. muricnta, the native Alanga which has 
very characteristic pseudo-prickles on its twining 
stem. Alanga is a wholesome vegetable with a 
pleasant nutty flavour, and when taken very 
young forms an excellent ingredient in pickles. 
The vine is a very prolific bearer. We may here 
mention that the larger fruits of I, bonanox 
(producing the beautiful while moon flower) 
are also eaten, though to a less extent. 
Perhaps we should liave first mentioned another 
Ipomoea as the chief among edible Convolvulacere, 
viz., /. batatas {Batatas eduUs) which is so 
largely cultivated in all the warmer parts of the 
globe and used as food for man and horses. 
A third Ipomoea is I. aquatica, a favourite as 
a native spinach, and known locally as " kaukun" 
supposed to be its Malay name. 
While in the Katnapura district we heard of, but 
did not see, a plant called "Madu" said to be a 
good standby fodder, and even eaten boiled by 
people. 
Mr. W. A. de Silva informs us that the leaves 
probably contain a good deal of starch and have a 
pleasant taste ; and refers us to three species, viz., 
7. c!/wosa (Maha-madu or Kiri-mndu), J. tridentata 
(Hawari-madu), and /. angustifoUa (Hin-madu). 
Mr. Silva is good enough to write with reference 
to this subject : I. unifiora (Potupala) is used for 
curry, and so are I, chryseides (Kaha tel-kola) and 
I. sepiaria (Rasa tel-kola). The two latter as 
their names imply are of an oily or fatty 
character. 
NATURE STUDY LESSONS. 
Second couksk in the stuI)Y of plant Life. 
3. the leaves. 
The surface of leaves, above and below, is 
covered with a very thin skin which, in 
some cases, can be peeled off, as in American aloe 
(gonigas). This skin may be looked upon as a 
waterproof covering, protecting the leaf in the 
game way as the outer bark protects the etem, 
Scattered throughout this outer skin or epider- 
mis are — especially on the underside — numerous 
minute openings through which gases from the 
air can pass in and out. Tlie interior of tlieleif 
consists of soft and spongy tis.sue, in the cells 
of which certain important changes are brought 
about. Running through the soft tissue are the 
veins (best seen when a leaf is held up to the light) 
forming a sort of ground-work or skeleton. You 
will sometimes find, lying under a tree, leaves 
that have been reduced to skeletons by the decay 
of the softer tissues. The veins themselves are 
tough, being continuations of the woody tissue of 
the stem, and serve to carry the liquid food 
(ascending sap) to the leaves. 
In a large class of plants the leaves show a 
netted arrangement of the veins, which are 
irregularly spread over the blade. In another 
large class the veins run parallel to one another. 
Compare the leaf of the mango or orange with that 
of the plantain. 
Vou will now be thinking that there must be 
some important work going on within the leaf, 
seeing that the liquid food, absorbed through the 
roots as well as the gases that enter through the 
leaves, ultimately find their way there. So there 
is ; and, iu fact, the leaf is sometimes spoken 
of as the laboratory (or workshop) of the plant, 
because it is there that crude plant food is 
prepared, or brought into a fit condition to 
serve as nutriment to the plant, just as our 
food requires to undergo various changes before 
it can be assimulated. The elements of plant 
food derived from tho soil, and those derived 
from the atmosphere combine to form compounds 
C pible of nourishing the plant. 
You now know something of the important 
functions performed by leaves in connection 
with plant nutrition, but it is also through 
the agency of leaves that the process of respir- 
ation is carried on. Plants, you must know, 
breathe just in the same way as animals. That is 
to say, they take up the life-giving oxygen 
from the air, and give out poisonous carbonic acid 
gas. This goes on through those minute openings 
we have already referred to (known as stomata) 
which may be looked upon as the leaf-mouths of 
the plant. 
You will recollect that, in speaking of tlia 
vipward flow of the crude sap through tha 
wood tissue of the stem, we made reference to 
the large quantity of water that passes out of 
the plant, through the leaves, in the form of 
vapour. This process, called transpiration, is also 
cai-Tied on through the stomata. 
So that the leaves, as you see, have very 
important functions to perform in connection 
with nutrition, respiration, and transpiration, 
about which I shall have more to tell you later. 
Many species of leaves serve as human food such 
as cabbage (gowa) and lettuce (salada), but, besides 
such well-known vegetables, there are a largo 
number of uncultivated plants, the leaves of tvhich 
are used in this country, such as .'L'rua (polkudu- 
pala) and other v.ild forms of vegetation which 
come in very handy for village diet. 
As instances of medicinal leaves, 1 may mention 
tlie species of Cassic^ which yield the Snglisb drug 
