Sept. 1, 1902.] Supplement to the " Tropical AgriciiUurisi." 
2rt 
This so-called discovery pvoves wliat observa- 
tion nnd tlioiiglit can do. Popped corn, rice 
and potatoes steamed in their jackets are all 
familiar enough, hut so long no one has seriously 
observed the coiKlitions under which these 
delicate and digestible products were produced 
and the possibility of acting upon other starchy 
food stuffs — free from an enclosing membrane 
or jacket under similar conditions. 
A word as to the value of popped Indiau- 
coru and other grains. Medical men have by 
experience found that such products are digestible 
and nutritious, and prescribed them as a suitable 
diet for children, just as they would prescribe 
extract of malt, possibly owing to the fact that 
the change resulting from "popping" were 
similar from a chemical point of view to 
malting. In a lecture on Native Food Stuffs of 
Africa by Mr. Open, administering the Agricul- 
tural Department, Rhodesia (we quoted from his 
lecture in our last issue), the peculiar sustaining 
power of popped Kaffir corn or sorghum is 
referred to and instances given of its value as 
n diet under trying circumstances. Mr. Open 
there says, "I am sure there is considerable 
chemical change in the parched and burst grain, 
and that analysis would easily show the reason 
of its nutritiousness." We have no doubt that 
with the developements in the direction of 
preparing starchy foods similar to popping 
grain, the chemistry of the process will be 
soon made clear. 
NATUEE STUDr LESSONS. 
riBST COURSl! IN THK STUDY OF PLANT LIFE. 
{Continued from August Number.) 
THE LEAF. 
Leaves differ greatly in size, shape and other 
characters, but most leaves agree in having n 
more or less thin, flat green portion called ilie 
blade. This blade is in some plants connected 
to the stem by means of a stalk as in the 
croton ; in others the leaf stalk is absent as 
in screw-pine (Wetakeyia). In addition to these 
parts some leaves bear at the point where they 
join the htem a pair of leafy structures which 
may be very small as in tlie sliue-flower 
(Sapatumal), or large and leathery as in the 
bread fruit which drops them as the leaves 
expand. These are called stipules, and their 
function is considered to be the protection of 
the leaf buds or young leaves before expansion. 
Notice in the plantain tree how the young 
leaves are for protection rolled up in the 
hollow stalks of older leaves. The protection 
of le f buds by scaley leaves is seen in the 
grap^> vine (Mndarapalam), and in the underj 
giou iid stem of ginger (inguru). Some leaves 
«te thick and fleshy as bowstring hemp (Neyanda). 
An onion bulb consists of a mass of succulent 
leaves closely packed round a tiny central stem. 
Here we have an instance of leaves storing 
food for the future use of the plant, as the 
swollen stem of the potato and the thickened 
roots of radish do. 
On the surface of leaves are certain markings 
due to the presence of tougher structures running 
through the leavds.- These are called veins, but 
unlike the veins iu our body, which are hollow 
structures for the conveyance of blood, the veins 
of a leaf are solid. The principal vein which 
generally intersects the leaf into two equal parts 
is [called the midrib. When this midrib is elon- 
gated or developed as in the mango, we get leaves of 
the pinnate or feather type, with veins branching 
out from it. When the midrib is contracted 
or undeveloped we get leaves of the palmate 
or hand type, as iu the pa^jaw (pepoi), in which 
the veins seem to spread out like the fingers 
of the band. There is a large class of plants 
in which the veins branch to form a kind of 
net work, ai in the orange (panjdodan), and 
another large class of plants iu which the veins 
run parallel to one another as in the plantain. 
In some plants — ferns (meemann) — there is a 
peculiar forked arrangement of the veins. These 
arrangements of the veins help us to classify 
plants. 
Notice in Glorioso superba (Niyagala) how the 
midrib of the leaf is extended to form a liooked 
structure which enables the plant to support 
itself ; this being another of the special arrange- 
ments for helping the plant to grow upwards. 
The surface of a leaf may be hairy as iu 
Coleus aromaticus (Kappra walliya), aud some- 
times these hairs are of a stinging nature owing 
to an irritating fluid they contain, as in Laportea 
cremulata (Ma-ussa^. There are also smooth 
leaves as those of domba.''- 
We have leaves of almost every shape -compare 
the heart-shaped leaf of Colocasial (Gahala), 
the kidney-shaped leaf of Si/drocoti/lc (Gotukoia), 
the nee(}le-like leaf of the whip tree (Casagas) 
the round leaf of the lotus (Olu) and so on. 
But leaves vary also according to the extent 
aird the manner in which they have been ^cut 
into. Compare the entire leaf of the jak with 
tlie irregularly cut leaf of the bread fruit or 
papaw. Note that a leaf which consists of one 
blade, no matter how much it has been cut 
into, is a simple leaf. But leaf wliich has been 
divided up into distinct parts (leaflets), each of 
which constitutes a secondary leaf (bearing the 
same relation to the midrib, as the leaf does 
to the branch) is a compound leaf. Take a 
rose leaf aud see how it consists of distinct 
leaflets. Examine a tamarind (Siyambala) leaf 
and see what you can learn from it iu this 
connection. 
A very strange form assumed by the leaf is 
the pitcher-like structure in the pitcher plant 
(bandurawel), but of this and other insect-eatin" 
plants such as the Drosera (wata-essa) 1 shall 
have more to say iu another lesson. 
You will also learn something of '• seed leaves " 
when I come to speak of seeds. 
THE FLOWEB 
I have told you that everything borne by the 
stem is a leaf or a modification of a leaf. Now 
the parts of the flower, you may be surprised 
to hear, are also modifications of leaves. 
• In this connection notice tbo prickles on the sur- 
face of the leaves of the wild'briujal (Katuwalbatu.^ 
