July 1, 1902.] 
THE TBOPIGAL AGaiCCJLTUIUST. 
11 
considerable importance as regards the yield of rubber 
milk obtained. In other words, the' application of 
the incisions should be based up n a knowledge or 
the anatomical structures, at least of the laticiferous 
tissue of the various trees. 
On the exiimple of L;i,ndolphia Heudelotti, M. Le- 
comte illustrated this point. Thi^i is a creeper 
which furnishes the bulk of the rubber of the tropical 
regions of French No;th Africa. Un producing a 
cross section through one of the branches of this 
plant, it may at once bo seeu that th'^ laticiferous 
tissue is situate in that part of the bark which is 
nearest to the wood. It is therefore quite necessary 
to penetrate into the woad with the incisions. 
The laticiferous vessels of this Landolphia run in 
comparatively straight vertical lines along the bark, 
and they are, to a moderate degree, only ramified and 
anastomosed (inter-cimmuni(?ating). From this it 
follows at once, that longitudinal inci.-jious, however ex- 
tensive, must prove very ineffective, the number of 
vesse's thereby opened bting vary small indeed. On 
the other hand, it will easily be recognised that hori- 
zontal incisions lay op"n the maximum number of 
vessels which may be reached by any single incision, 
and thus must produce the gieatest possible yield of 
latex. Of coursi', there ia the objection to horizontal 
incisions that they do not lend themselves so readily 
to the c'jlieetion of the latex by the simplest means. 
This difficulty is, however, easily avoided by producing 
these incisions at an obliquity just snfdcient to in- 
duce the flow of the exuding late.^ towards a channel 
c mmon common to a number of such incisions. 
There is another important advantage in these trans, 
ver.'al incisions which is worth calling attention to. 
In consequence of the constant incrense in bulk of the 
ligneous core which is surrov.nded by the bark, the 
latter is under very considerable tension, and exerts a 
corresponing pressure upon the whole of the tissues. 
This tension of the bark, which exists in every tree, 
can easily be demonstrated by catting an annular band 
from the bark of some tree, and then trying to place 
it again into poison, when it will be found impossible 
to make the ends of this band meet. 
It is exactly this tension which causes the flow of 
the lalex from the laticiferous vessels in which it is 
hf Id by capillary action. Now it is perfectly clear that 
vertical incisions, apart from laying open very few 
laticiferous vessels, must in a large degree have the 
effect of relieving that tension with the result that 
capilhn-y att.-action maintains the upper hand, and we 
obtain only a feeble flow of latex. Prom these various 
points we arrive thus at the conclusion that horizontal, 
or transversal encisions are the most rational . Never- 
theless, it should be borne in mind that by making 
such incisions indiscriminately all over the trunk of 
a tree the latter would very soon become worthless 
for tapping purposes. Each transversal incisions severs 
of course the connection between a large number of 
laticiferous vessels, which, when the incision has again 
healed up remain separated, so that if these incisions 
a' e made in an unsystematic manner they very rapid! v 
result in dividing the whole of -the laticiferous aiod, 
of the bark into a number of disconnected section's, 
each of which is capable of a very restricted 5ield 
of latex only —India- J/uMer and Gutta-Percha Trades' 
Journal. 
PREPARATION OF COMMERCIAL 
PAPAIN. 
It is well knovv-n that the milk obtainable espe 
clally from the fruit, of the papaw^ tree ( Garica 
Pajioi/a possesses the property of rendering meat 
tender and in fact of partially digesting it. In recent 
years this property has been utilized by evaporating 
the milk into a dry powder known as ' papain. ' 
There is a moderate demand for this substance and 
where the papaw tree is abundant it might be advan- 
tageous to prepare it. The following account of 
preparing crude or commercial papain has been 
contributed by the Hon'blo Franci.s VVattu f i c. 
p.c,.=. ;— ) • • . 
Tlie preparation of crude papain is a comparatively 
easy matter, provided that attention is naid to 
certain matters of detail. 
COLLECTIKf) THE MILK. 
The juice, or milk, which forms the starting-point 
IS procured by making a scratch or shallow incision 
in the skin of the fruit of the papaw while in a 
green condition. It is desirable to employ a bone 
or wooden knife, like a paper-knife, for the purpose 
_ The milky fluid rapidly exudes and may be caught 
in a cup held beneath the fruit. After a time the 
How diminishes and the liquid coagulates in the 
neighbourhood of the incision, this is carefully 
removed by means of the bone or wooden knife 
and placed in the cup with the milk already collected. 
Ihe fruit is not removed from the tree and is 
may be subjected to the oparation of tapping several 
tunes at intervals of two or three days. It is essen- 
tial that no iron knife, or i:on utensils, should be 
brought into contact with the milk. Wcol or bore 'hould 
be employed, and the mdk should bo collected 
in earthenware basins or cups, or in glass vessels 
and not in tins, which are sure to blacken it. 
After collecting the juice soon becomes coagulated 
and then should be in the form of a snow-white 
curd, possessing a somewhat pungent, but not putrid 
smell. It speedily decomposes if not rapidly dried, 
and, when decomposing, emits a most unpleasant 
odour. It IS necessary then that drying should be 
effected as speedily as possible. When considerable 
quantities are being prepared, the collection of the 
juice or nulk should be undertaken in the early 
morning and the drying should begin before mid- 
day. This ensures that by evening the material 
13 in a suflioiently diy condition to keep without 
deterioration until the following morning when the 
drying can be completed. 
DKYING THE MILK. 
The drying may be effected in several ways In 
dry, hot weather the congulated milk may be 
placed in thin layers on sheets of glass and exposed 
to the sun. This, however, is rarely satisfactory 
on a large scale, and it is best to adopt some form 
of drying apparatus. Drying is well eflected by 
spreading the coagulated milk on drying frames made 
by stretching bro«n linen on light wooden frames, 
somewhat like those used for framing school slates ■ 
ihese may bo of any suitable size to fit the drying 
pparatus employed. 
D 
Fig. 1. Elevation. 
A small American frnit drier will answer very well, 
or a drying-stove (Fig. 1) may be constructed by 
building, in brick, a chamber about 3ft. high, 3ft 
wide and Gft. long, these domeusious can be changed 
in accordance with the amount o£ material to be ^ealt 
