22 
THE . TROPICAL 
AGRigHLTURIST. [July 1, 1901. 
filled with sugary-acid juice. The whole resem- 
bles yellowish white mucilage, This is probably 
Landolphia ovariensis. 
The rosy caoutchouc is probably a variety of L. 
ovariensis'; it also is a sturdy Liana, the stem 
of which is sometimes 6 inches in diameter. It 
bears small, pyriform, yellowish-green or red- 
flish-G;reen fruits, with, at maturity, a 
"nubly" wrinVded skin, and containing from 
four to twenty seeds, surrounded with yellowish- 
white hairs filled with acid juices. This yields the 
most valuable rubber ; specimens quoted 4s. 5d. 
per lb. Native uames for the plant are Bongovv, 
Mongevv. &c. 
Black caoutchouc (Mondongo, Boole, Sic), or 
Landolphia florida var., is a sturdy Liana, the stems 
from 4 to 6 inches across, bearing round fruits,easily 
recognisable, as the seeds are surrounded with a 
blood-red viscous pulp. Tliey number from four to 
ten. 
The Congo caoutchoucs'are remarkable for their 
purity. The natives coagulate the milk either by 
precipitation in boiling water, or by the addition 
of a very acid juice, which at once incites the 
collecting together of the molecules held in sus- 
pension in the milk. Thus are both the white 
and the red caoutchouc coagulated immediately 
by the addition of juice from a plant known in 
all the equatorial regions as Bosasanga, the Cos- 
tus afer. A fine specimen, brought from the 
Congo in 1896 by Professor Laurent, of Gembloux, 
is. in the Victoria liegia house at Kew. 
The rubber of the black caoutchouc, however, 
is not influen(!ed by this material, and is only coag- 
ulated by precipitating it in boiling water. It is 
ignorance of these facts that cause the produc- 
tion of inferior rubber. For instance, if the native 
gathers in his calabash the white and the black 
rubber, and submits them to the influence of the 
Costua juice, the white rubber coagulates, and 
includes the molecules of the black rubber with 
it, but remains always more or less viscous. Simi- 
larly, if the mixture is precipitated in boiliiag w!>,ter, 
the black rubber coagulates immediately, but as 
it encloses the white, the mass is depreciated in 
value. Thus merchants recommend that the differ- 
ent kinds be collected separately. Other natives, 
instead of percipitating the mondongo in boiling 
water, simply boil the milk, thus forming a porous 
and elastic mass. Coagulation with Costus juice 
is practised thus : the milk flowing from the in- 
cisions is first collected in leaves left under the 
cuts, then gathered into calabashes and taken to 
the village. While one man cuts the Costus canes 
and strips off the leaves (it is a somewhat shrubby 
plant, sending up suckers from 3 to 6 feet high, 
and from to 1 inch in diameter), another man 
passes a piece of Banana leaf over the hre, ren- 
dering it wonderfully supple. A small hole is made 
in the ground in which the Banana leaf is laid 
and the milk poured into it. Three or four canes 
of Costus taken together are twisted above the 
milk, which coagulates immediately under the 
action of the acid juice. With the hands it is made 
up into a ball and fiimiy pressed until the rubber 
is all extracted. 
it is noticeable that all caoutchouc coagulates 
naturally by .simple (-.vaporatinii if loft in .^hallow 
vessels in airy .umI .shady pUioes. The product 
thus obtained is absoluttly pure. 
The cjioutchouc Liana is found in all equatorial 
forests, whether these are inunrlated or not, and be 
the soil clay or sand. In the Congo (according to 
the botauiHt E de Wildeman) are found Landolphia 
Hendelotii, ovariensis, Kirkiivar., Klainii, lucida, 
florida, and florida var. leiantha ; Carpodinus an- 
ceolatus, turbinatus ligustrifolius, leptanthuf; Oli- 
tandra gracilis, myriantha, Maunii, Schwein- 
f urchii, visciftua, and cirrhosa. 
Several ways of propagating have been triijd, 
as by cuttings, layering, collecting seedlings, auil 
seed-sowing. Cuttings are not successful except 
when managed by practised hands, under glass, 
and where there is bottom heat. I have seen 
thousands, and not one has rooted. Layering oa 
a large scale is not practicable, as it is too slow a 
method. 
As regards the collection of seedlings it should be 
said that the ripe caoutchouc-fruits fall from a great 
height and generally break in so doing. The 
seeds retain germinating power but a short time, 
and owing to the very moist atmosphere of the 
undergrowth they germinate all together in the 
fruit, sothat the fruits must be collected and the 
young plants separated. This task must foe per- 
force trusted to natives who would gather the 
whole of the seedlings beneath the trees, and so 
they would exterminate the young plants found 
in the forest. 
The chief propagators of the caoutchouc Lianas 
are the apes who swallow the ripe fruits whole, 
and the undigested seeds germinate perfectly 
afterwards. This I discovered through a native, 
when I asked him if certain species did not grow in 
dry as well as in inundated forests. He replied, 
"Do not the apes climb all the trees." Another 
unconscious planter is the native who is also fond 
of the Liana fruit, so that frequently near a 
village small plantations arise full of caoutchouc 
Lianas accidentally established there. 
MULTIPLICATION. 
To turn from these casual acknowledged 
methods of cultivation, it may be said that the 
rubbers grow best from seed. The nursery must 
be made in the forest in a space between fine trees 
that is large enough for the formation of several 
borders. No tree must be cut down, and there 
need be no large plantation in any one place. The 
borders must be fenced but not roofei as the 
trees around afford sufficient shade. Each border 
should be about 3 ft. 6in. wide, and of any pre- 
ferred length, and several borders may be divided 
by narrow paths. If the ground is sloping, the 
length of the border should be parallel with the slope 
and the plantation should be surrounded with a 
ditch, to keep the seeds from being washed away. 
The nursery can only be established when the 
fruits are ripe unless the soil is not in a fit con- 
dition for the seed to be sown. 
Fruits brought in by the natives are at once 
opened and seeds are sown singly, thrusting theni 
with the finger half an inch into the soil and each 
seed half an inch to an inch away from its neigh- 
bour. I insist on the immediate sowing of ripe 
seed, as dry seed is useless. Unripe fruits become 
ripe if stored. Germination generally ensues in a 
fortnight and when the seedlings have eight leaves 
they are easily transplanted. Seed in the nursery 
grow equally well as that en place ; the fruits 
remain ripe for two or three months only. It is, 
therefore, advisable to gather as many as possible 
to be sown in an allotted space in the forest pre- 
pared for them, 
PLANTING. 
The nursery-ground made and the seeds planted, 
the space to be allotted to the Lianas is marked 
out in plots of (say) 24 acres. A central avenue is 
