Jan. 1, 1903.] 
TliE TROPICAL AGRICULtUfelSt. 
to by coagulating it in conjuncticn wilh the albumen 
present, and we bave at orce a piocliict possess- 
ing all the iiiemediable drawbacks which above we dis- 
cussed at s< me lergih. 
On (he planlaticn at Lag Cascada?, Calonyction 
Epeciosum is veiy common, ar.d I asceitnined 
that decoctions prepared from it have a strongly 
acid reaction. Therefore, crngulalion wiih tuch a 
decoction is timply the wellknown coagulation of 
EoUuions of albumen with acids. I have Lot been 
able to discover at Las Cascadas Ipomoea bona 
nox. but 1 very much drubt the highly alkaline 
character tf its juice which it is almost certain to 
possess likewise a distinctly acid reaction. T he treat- 
ment wilh alum, a process due to H. A. Strauss, 
and purchased from him by the local government 
of the piovince of Pernambuco, owes its ccagulaling 
acticn entirely to the sirtiigly acid reaction of that 
salt. This pircess is a bad one fiom eveiy pcict 
of view. The removal of the alunr solution from the 
coagulated lubber is physical impossibility, inA the 
pernicious action cf an alum solution upon the 
drying rubber is quite sulficient to render ils con- 
tinr.ed emplojmeui; most deplorable. The coagula- 
tion wilh soap as practised in the Isthmus cf Panama 
is barbarous in the e.xtieme, and it is not snrpris- 
ing ihat it yields a product of veiy bad qualiiy 
indeed. 
Amongst the above-named processes 1 have not 
enumerated a process said to be practised in Me.xico, 
and simply consisting in the boiling of the latex 
in earthen vessels (jacara^). If this process is ac- 
tually used, it can certainly not be carried out with 
the fresh latex for the simp'e reason that over 
and over again have I saiirfied myself that even 
on very prolonged boiling of the slightly diluted 
latex furnished by the tree at Las ( ascadas no 
coagulation c:in be obtained. The cause of this is 
to be found in the fact that the aqueous vehicle 
of this latex, although it certainly contains a large 
amount of albuminous matter when rapidly separated 
fiom the la' ex immediately after this has teen 
obtained, is of a very light olive green colour and 
even on very prolonged boiling does not coagulate, 
nor even become turbid. On standing exposed to 
the air this aqueous vehicle very rapidly assumes 
a darker colour, and eventually forms an almost 
inky liquid. This, on boiling, undergoes immediaie 
coagulation, and a most copious deposit of insolu- 
ble albumen is obtained. In entire agreement wilh 
this observation is the fact that if the Castilloa 
latex be allowed to stand for scmelime until it 
has assumed a very dark colour it will new be 
found that on short boiling rapid and compli te 
coagulation takes place. 1 have not yet succeeded 
in aicerlainirg the cause of this carious phencme- 
lioD, but it is obvious that unless the Castilloa latex 
obtained in Mexico differs very considerably from 
the latex yieldsd by the same trees in the Isthmus 
coagulation by boiiing in Mexico, must be preceded by 
an ageing of the latex as olheiwise no coagulation 
would take place. 
It is not very easy to see that (he chief point in 
attempting to prepare a pure rubber from the latex 
of Castilloa elastica, and as a matter of fact, from 
the latex cf any other n;bber tree, must consi-t 
iu the elimination from the rubber,prior to its " agglu- 
tination," of all albuminous matter, The first step 
in this direction is the diluting of the crude latex 
Tvith water, of which at least live times the volume 
of the latex treated should be used. In the case of 
the thick, cuidy latex yielded by the trees at Las 
Cascadss it is preferable to use actually boiling water, 
but in how far this applies to the latex obtained in 
other districts or fiom different trees is a matter 
lor experiment. Boiling water at once C( u\erts this 
latex into a thin, very fluid milk which through a 
common cotton gauze is strained in oider to remove 
from it any insoluble impnrites such as earth, wood, 
bark, and the like. This milk is best strained into 
tboroughly well. washed petroleum barrels. As eoon 
as the barrel is completely filled, about 8 ons. of 
fornialdebyde are added, the whole wt-U stirred, and 
allowed to stfind for 2-1 hours. The action of the 
formaldehyde appears to be twofold, lu the first 
instance, it effectually pievents any tendency of the 
albumen to ccagnlate in the hot solution, and 
thereby to cause mischief. But, as comparative ex- 
periments showed beyond any doubt, it also has a 
most distinct effect upon the iudia-iubber, which 
collects on the top of the washwater in the form of 
a snow-white cake of rubber of such strength and 
tojghness that it can in one mass be lifted out 
frcm the barrel. On cutting this cake oper', it will 
be found that it is rather spongy, being lull of little 
holes which are still filled with some of the albu- 
minous, though very dilute, mother liquor. If. there- 
fore, the rubber were dried in this state it is obvious 
that it would still contain a small quantity of the 
ol jectionable albuminous matter. t'or this reason 
the rubber contained should at once be taken, cut 
into strips, and subjected to a thorough washing 
upon an ordinary rubber washing machine. As ail 
albuminous matter present is still iu a state of 
peifect solubility there is no difficulty whatever of 
completely removing every trace of it by carrying 
out the VI ashing with a plentiful supply of water on the 
wa-hing rollers. 
The ruber thus obtained is a product of a degree 
of purity in which no rubber, not even the finest 
brands of Para, has ever been offered to the manu- 
facturer. It is absolutely free from solid impurities 
(f any description, it contains no trace of either 
sohibe or insoluble organic or inorganic impurities. 
Of course it contains a small amount of resinous 
matter combined wilh only a trace of the consti- 
tuents known as " ash. " The arrount of these 
resinous matters is extremely small, and they are 
of an entirely innocuous nature, so that any attempts 
to remove them, which would call for a somewtiat 
energetic chemical treatment, would be altogether 
out of place. In a further communication I in'end 
to give the analytical data of this pure Castilloa 
rubber. 
When dry, the condition in which the owners of 
the Las Cascadas, plantations intend to ship this 
rubber, it forms a product which requires no pre- 
paratoiy operation on the part of tie rubber 
manufacturer, but which may at once be taken 
into operation for tbe manufacture of rubber goods 
of every description. Kor need any fear be enter- 
tained that rubber of this description is in the least 
liable to suffer tuch detrimental changes duiing 
transit in the ships' holds, which are at present so 
common owing to the "heating' (fermentation) of 
the rubber during transit. Indeed, a considerable 
lot of this which was purposely packed and shipped 
in the excessively wet condition in which it came 
cff the rubber washer, had not undergone the least 
change, still less any deterioration on reaching this 
country, 
An analysis of a sample taken of one of these 
dry sheets of rubber gave the following results:— 
Resinous Matter 2'61 p.c. 
•■ •• '. 0-44 p'.c! 
Nitrogenous Constituents . . Nil. 
Insoluble Constituents .. .. Nil'. 
The sheets themselves are extremely light iu colour 
semi-transparent, and when dissolved iu the usual 
rubber solvents form almost glass clear 6olution« 
The characteristic rubber smell is almost entirely 
lacking, certainly much less noticeable than in even 
the finest Para rubber. The strength of these sheets 
is distinctly superior to thut of washed and dried 
sheets of Para rubber. How this Castilloa rubber 
after vulcanisation compares with Para rubber, and 
how in general it behaves in the vulcanising process 
as compared with Cascilloa rubber in its present 
day ciude and impure form. I have cot leer able 
yet to ascertain. This work is, however, in progress, 
in due course I will report the reiulta ootaiuedi 
