THE TROPICAL AGRICULTURIST. 
[August r, 1881, 
FIBEES. 
(From Span's " Encyclopedia-") 
Fibrous Substances [derived from Plants] (Fit., 
Fibres Vegetables ; Gee., Pflanzenfasern). 
The "fibrous" portion of plants consists essentially 
of cellulose Go H10 O5, a carbohydrate which shows 
great resistance to re-agents that produce a marked 
effect on the other portions of plants. This resisting 
property constitutes the value of such fibres for the 
production of textile and other fabrics. The indus- 
trial application and commercial value of a fibre de- 
pend principally upon its physical qualities of length, 
strength, elasticity, firmness, and colour, and upon 
its capacity for taking dyes. The majority of these 
qualities are affected more or less by the mode of 
cultivation, the period of harvesting, and the method 
of preparation. 
The varying position of the fibres of different plants 
lias given rise to a threefold classification :— 
(1) Monocotyledons, or endogens, are plants which 
«io not form a true bark, and which grow by virtue 
of a buildiug up of tissue from within. These plants 
yield " foliaceous " fibres, imbedded in the cellular 
tissues and pulp of their roots, steins, and leaves, 
which fibres rarely attain sufficient development to 
be of commercial utility, except in tropical and sub- 
tropical regions, and may, in almost all cases, be 
separated by simple mechanical processes. 
(2) Dicotyledons, or exogens, are plants which do 
possess a bark, and whose growth is purely of an 
external character. Their fibres reside in the sheath 
•of bark or bast, and hence are called "cortical." 
They aro abundant in temperate climates. The fibres 
are in an agglutinated condition, held together by 
means of a tenacious gum, the removal of which 
necessitates special, and in some cases laborious, treat- 
ment. 
(3) In a few plants the seeds are enveloped in a 
liairy covering within the pods ; these are termed 
11 seed hairs," or "capsular" fibres. 
Examination. — Haviug regard to the fact that many 
iibre-yieldiug plants still remain, to be examined, and 
for convenience of reference to the characters of, and 
means of distinguishing, fibres treated of in a sub- 
sequent part of this article, instructions for conducting 
chemical and microscopical investigations, as suggested 
by V6tillart and others, may here be briefly given. 
The fir3t step is the separation of the fibres from 
the remaining portions of the plant, which may be 
effected by boiling the sample in a solution contain- 
ing 6 per cent of carbonate of potash or soda. When 
the separation is accomplished, the sample is well 
washed, pressed, and dried. If the washing does not 
suffice to complete the disunion of the fibres, they, 
may be bruised under water in a porcelain mortar, 
with a pestle of hard polished wood. The separated 
fibres are then divided into three portions : — (1) For. 
examination longitudinally in neutral liquids ; these 
are at once placed to macerate in water and glycerine ;, 
(2) for longitudinal examination under re-agents, are 
put aside to dry ; (3) for examination in transverse 
section ; this sample is straightened as well as possi- 
ble, and then put to dry. 
A.— Of sample (1) some threads are taken and 
placed on a glass slab under a microscope ; they are 
then bathed in pure concentrated glycerine, two or 
three entire isolated fibres are picked out, laid paral- 
lel, and moistened with sufficient glycerine to keep 
them in place. Care must be taken that the ends 
are intact and the fibres entire. Their length is then 
estimated, and the operation is repeated upon a num- 
ber of samples. The mean length is, perhaps, most 
correctly stated as that which occurs the greatest 
number of times. 
(B). — These fibres are next examined in neutral 
liquids having a refractive power as nearly as possible 
i like that of the object itself, such as a solution of 
[ chloride of calcium of the consistence of clear syrup 
or glycerine, either alone or with the addition of a 
l little camphor-water and a few drops of acetic acid. 
One or two fibres are laid in the liquid on a glass 
plate being cuded spirally to diminish their length, 
and are covered with another thin sheet of glass. 
Repeated observations are then made as to whether 
the fibres are solid, or in flattened bands ; whether 
rounded or prismatic ; whether smooth, or fluted, or 
striated ; whether an internal cavity is visible, and 
whether it is large, continuous, or interrupted. A 
number of measurements of the diameter of the fibres 
are then made, carefully noting the maximum, minim- 
um, and mean, and the degree of tapering or irre- 
gularity. 
G. — Sample (2) is next examined under re-agents — 
iodine solution and sulphuric acid diluted with gly- 
cerine. The former is prepared as follows :— 1 gnu, 
pure iodide of potassium is dissolved in 100 grm. 
distilled water, and an excess of iodide is added to 
ensure constant saturatio".. It is kept in glass-stop- 
pered bottles, always containing a few pieces of the 
iodide. The solution is liable to change at the end 
of a few months, and must then be renewed. The 
dilute sulphuric acid is thus prepared :— 2 volumes of 
pure couceutrated glycerine (Price's) are mixed with 
i volume of distilled water in a flask ; the latter is 
plung d into cold water to the level of its contents, 
and 3 volumes sulphuric acid, sp. gr. 1-845, are 
added with constant agitation. This solution also 
undergoes gradual change by absorption of moisture, 
when a slight addition of acid be'-ome3 necessary. 
Some thoroughly dry fibres in a complete stale of 
division are selected from the sample and briskly 
rubbed between the fingers ; they are then placed on 
a glass plate on the object-holder, and covered by a 
few drops of the iodine solution. The latter is allowed 
to thoroughly penetrate the fibres, and the excess is 
removed by blotting-paper. The test is then covered 
with a small piece of glass, along one edge of which 
are poured a few drops of the sulphuric acid prepara- 
tion. The liquid penetrates between the two glases, 
and advances towards the other side, where slips of 
blotting-paper are placed to absorb it. The current 
is maintained for a little while by occasionally add- 
ing a few drops of the acid and renewing the blot- 
ting-paper. The result of this operation soon becomes 
evident in the distinct coloration of the fibres. 
Wherever cellulose is present, it assumes a blue or 
violet tint ; where the cellulose is iignified or pene- 
trated by foreign matters, it becomes yellow. This 
tint, which varies frow bright yellow to brownish- 
yellow, appears also in the fragments of tissue ad- 
hering to the fibres, and in the matters occasionally 
found in their interior cavity. The coloration must 
be clear and pronounced, and the fibres must be in 
perfectly sound condition ; when the results are im- 
perfect, the sulphuric acid preparation may need 
strengthening. The blue colour will disappear in a 
few hours, and the yellow will not last beyond a day 
or two. The re-agents occasionally disclose striations 
or transverse lines of deeper tint, generally arising 
from folds in the fibre which afford additional charac- 
teristics. 
D. — Sample (3) is divided into transverse sections, 
perpendicular to the axis of the fibre ; these furnish 
the most precise indications of the form, structure, 
and thickness of the walls of the fibres. Sufficient 
fibres are taken to form a bundle about as thick as 
a goose-quill. About 1 in. of this is cut off and tied 
in the middle by a thread. One end of the bundle 
is placed in thick glue, and then the other end, and 
both are pressed between the fingers to ensure the 
close adhesion of the fibres and to express the super- 
fluous glue. The bundle is then hung up to dry, an 
operation requiring at least 12 hours in summer and 
