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THE EXPLOITATION OF
PLANTS

THE IMPERIAL STUDIES SERIES

EDITED BY
A. P. NEWTON, M.A., D.Lit., B.Sc.
Cr. 8v0, cloth, 2s. 6a. net.

THE OLD EMPIRE AND
THE NEW
BY THE EDITOR

THE STAPLE TRADES OF
THE EMPIRE
BY VARIOUS WRITERS

THE EXPLOITATION OF
PLANTS
EDITED By Pror. F. W. OLIVER, F.R.S.

J. M. DENT & SONS, LTD.-

THE IMPERIAL STUDIES SERIES

THE EXPLOITATION
OF PLANTS

BY VARIOUS WRITERS

EDITED BY

F. W. OLIVER, F.R.S.

QUATY PROFESSOR OF BOTANY IN UNIVERSITY COLLEGE, LONDON

MCMXVIL
LONDON AND TORONTO

J. M. DENT & SONS, LTD.
PARIS: J. M. DENT & FILS

&

PREFACE

Durinc the first term of the present year the subject
matter of this volume was delivered in the form of
Public Lectures at University College, London, by the
several authors. The object of the course was particu-
larly to bring before young botanists, and also such
members of the general public as cared to attend, some
account of prevailing methods of plant exploitation, and
of the field awaiting development in the matter of our
great and varied resources of plants from the botanist’s
point of view. It is of course evident that the chap-
ters in this book touch but a very small part of the field
of plant exploitation. At a time like the present, when
so many of our experts are serving their country in
various ways, this is just what was to be expected ;
nevertheless, the subjects dealt with are sufficiently
representative of the whole to make the lectures worth
publishing in book form,so that a wider public may be
reached. Signs are not wanting that our neglect in
the past adequately to develop our resources is now
beginning to be generally recognised, and if this book
can help, in however slight a degree, in-the new
“ push,” it will have served its purpose. It is at the
desire of the contributors that I have undertaken the
pleasant duty of seeing this volume through the press.

F. W. O.
June, 1917.

CHAP.
I.

II.

IIT,

CONTENTS

INTRODUCTION
By F. W. OLIvEr, ERS.

PLANT FOOD AND SOIL PROBLEMS
By W. B. Botromiey, M.A., Ph.D.

WASTE LANDS
By F. W. OLIvErR.

TIMBER PRODUCTION IN BRITAIN
By E. J. Sarispury, D.Sc., F.L.S.

TROPICAL EXPLOITATION, WITH
REFERENCE TO RUBBER .
By J. C. Wirtis, M.A., Sc.D.

THE COTTON PLANT, ITS DEPENDENT IN-

SPECIAL

DUSTRIES, AND NATURAL SCIENCE .

By W. Lawrence Batts, Sc.D.

VEGETABLE DYES . :
By the late Saran M. Ragen aD); Se.

TEA-MAKING :

By S. E. CHANDLER, DSe,, ARCS. FLS.

THE PLANT AS HEALER
By Eruert N. Tuomas, D.Sc.

PLANTS AS A SOURCE OF NATIONAL POWER—

COAL. é
By Marie C. SToPEs, DSc., Ph.D.

PAGE

Ld

25

43

62

99

T20

140

155

THE EXPLOITATION OF
PLANTS

CHAPTER I

INTRODUCTION

By F. W. OLIVER
Quain Professor of Botany in University College, London

It is not possible to say offhand what proportion
“commodities of vegetable origin bear to the total of all
merchantable goods. The volume of trade in plant
products may be guessed to be not less than one-half,
and, if coal be included, may well exceed 60 per cent.
of the whole. Moreover, animal products derived from
the herds which we tend depend largely on a proper
ytilisation of the plants which form their food, so that
the exploitation of animals is closely related to our
present subject matter.

The reason for this pre-eminence of plants is, of
course, the fact that the plant is the universal agency
by which inorganic matter is worked up into organic.
It is true that chemical research has been able to build
up synthetically not a few organic substances, including
many that are not known to be produced by plants in

B

2 EXPLOITATION OF PLANTS

Nature, and it is evident that this number will go on
increasing indefinitely. Nevertheless, until the secret
of the universal function of green plants, the chloro-
phyll‘mechanism, has been discovered, we shall be well
advised to hold fast by the plant as the giver of nearly
all good things. Even if we suppose that one day
cellulose will be made synthetically, it is hard to believe
that it will ever be possible to manufacture it in a form
to compete with timber and vegetable fibres as they
are given us by plants.

Actually the triumphs of synthetic chemistry often
serve to stimulate a threatened plant industry to re-
doubled efforts. Thus synthetic indigo has not yet
driven the natural product from the field. The effect
of competition is to eliminate waste on the one hand,
and on the other to call forth a more economic pro-
duction, an increase of the output of indigo per plant,
partly by cultural means, partly by improving the
strain. As a consequence of the relaxation of competi-
tion with synthetic indigo, due to the war, it is interest-
ing to see that the natural product has received a new
lease of life. For we read that the acreage of the
current crop in India has been doubled, and that the
output is expected to be increased in 1917 by some-
thing like 75 per cent. as compared with 1916,

The products which we derive from the vegetable
kingdom are without number, and it is possible in a
little book like this to attempt to deal with only a very
small selection indeed.

These products vary in the complexity of the manu-
facturing processes required to make them available,

INTRODUCTION 3

from the relatively simple case of timber, which is
felled, dried, cut up and distributed, to fats and volatile
oils, glucosides and alkaloids, which require elaborate
processes of chemical manufacture for their production
and extraction.

Sometimes the source is a wild plant available in
quantity. Such are the timber trees of primeval forests,
Para rubber as it grows in Brazil, esparto grass for
paper making, and a host of others. Nevertheless,
there remain a very great number of wild plants, grow-
ing socially in immense stands and easy to get, for which
no remunerative use has been found. For instance,
the bracken fern, an almost cosmopolitan plant, is
useless except for litter, whilst the Zostera of the sea
shore, available in unlimited quantities, makes a stuffing
for inferior mattresses, and has a limited use as packing
material for venetian glass. On the whole, wild plants
are exploited much less than might be expected. Their
exploitation requires fertility in ideas and courage in
their development; for the product to be a success
must either displace some staple, or it must satisfy
some taste or fulfil some requirement not yet created.
In the one case the exploiter is up against a vested
interest, in the other against inertia. On the whole,
there is a great tendency to introduce and cultivate
established plants rather than to improve and make
valuable the indigenous plants of a territory. The
empire affords many examples of this.

Moreover, in the exploitation of wild plants there is
always a liability to overcropping and destruction with-
out replacement, so that in the absence of regulation
the source gets more and more inaccessible. It then

4 EXPLOITATION OF PLANTS

becomes profitable for the planter to step in and give
us, e.g. plantation rubber.

In the case of crops raised under control, it is of the
greatest importance for the cultivator to realise at the
outset for what precise purpose his output is destined.
With this knowledge he may at every stage in cultivation
—by selection of variety, by manuring, thinning,
pruning, and so on, promote a close approximation to
the specification. The forester should consider the
requirements of the carpenter; the tea planter the
taste of those he desires to pay for the privilege of
sipping his beverage; and equally in other cases.

Exploitation without consumption.—This is a branch
of the subject which, not being dealt with elsewhere in
this book, may receive passing reference here. It is,
briefly, the department of economic botany wherein
plants are employed as a substitute for the constructions
of the engineer, more especially the rendering of ground
which is mobile, from whatever cause, secure. Hitherto
it has been practised only in occasional instances,
and its possibilities are not realised as fully as they
should be.

The best-known example and the most highly
elaborated is the planting of sand dunes with marram
grass (Psamma) and other sand-binding plants. The
technique of dune protection by planting, though
developed into a fine art in Gascony and the Baltic,
is not well enough known in quarters where it might
be of service.

Other cases to which planting is applicable are those
of travelling beaches, eroding cliffs, the banks of rivers,
and steep sloping ground liable to crumble or develop

INTRODUCTION 5

slip, as in the case of the banks of railway cuttings.
The most troublesome case is that of slip, of which the
cause is easy to formulate. When the banks dry in
summer the surface cracks; and later on, by these
cracks, water gets access, rendering a deep-seated zone
plastic so that the superficial layer tends to slide down
the incline. As a consequence, railway companies are
put to great expense in remedial measures, especially
drainage, cutting away material so as to reduce the angle
of slope, constructing brickwork and masonry, etc.

Probably this particular sort of trouble could be
met by appropriate afforestation, and it is remarkable
that the companies should not possess in common an
experimental department of forestry to advise them
on these and analogous problems. Perhaps something
of the kind may be established in the future should our
railways remain permanently under unified control
after the war.

Tue BoTANICAL EXPLORATION OF THE EMPIRE

A matter of the first importance, if our vast resources
are to be properly and systematically utilised, is the
botanical exploration of the empire.

In his interesting Address as President of the
Botanical Section of the British Association at New-
castle-on-Tyne, Dr. A. B. Rendle alluded to the way
in which in the past our possessions have been explored,
and expressed the hope that it might be possible to
arrange an Imperial Botanical Conference after the war,
at which matters of this kind could be discussed. This

6 EXPLOITATION OF PLANTS

proposal is likely to meet with general approval, and it
is to be hoped it may bear fruit.

The first definite step in the botanical survey of the
empire was taken sixty years ago at the instance of Sir
William Hooker, the then Director of Kew. Accord-
ing to the plan arranged, twelve floras corresponding
to the various possessions and colonies were to be
worked out at Kew by the staff in what leisure time
was available.

Though subject to much interruption, the greater
part of this scheme has been completed, two of the series
of projected floras alone awaiting completion. Canada,
for some reason, was not included, but the omission is
likely to be repaired by local effort.

“The materials on which these floras have been based
are collections made by occasional travellers, officers
accompanying boundary commissions, missionaries, and
medical men attached to punitive expeditions. The
whole thing has been characteristically haphazard, and
it does great credit to the writers of the floras, largely
men fully occupied with administrative and routine
duties, that the enterprise should have been as successful
as it undoubtedly has been.

A flora, of course, is a mere starting-point, a bare
inventory of the plants of the area dealt with, and much

“remains to be done. Detailed physical descriptions of
the countries are now required, giving a picture of their
resources, stating to what extent, if at all, these are at
present utilised, the existing lines of communication,
available labour, and everything pertaining to the
development of their resources.

Meanwhile in most of the British possessions botanic

INTRODUCTION 7

gardens have been founded, and each Government
possesses a department of Agriculture, all in their
several ways doing a good deal to promote the local
exploitation. It is hardly necessary to emphasise the
importance of having attached to every district an expert
systematic botanist. Very slight specific or varietal
differences between allied plants are often of critical
significance in matters of exploitation, and it is of funda-
mental importance, when a given plant is found to be
adapted to a particular purpose, that we should know
“how to recognise it with certainty. Thus some years
ago a certain species of timber was exported to the West
Indies from British Guiana, and was found to have the
rare and valuable property of resisting the attacks of
boring molluscs when used for piles, jetties and similar
maritime constructions. Apparently no record of the
species of tree was kept at the time, and it is stated that
its identity has been lost, and that further consignments
are unobtainable in consequence. Cases of this kind
could be multiplied indefinitely, but with proper
organisation their occurrence should be impossible.
It seems eminently desirable at the present juncture
that the whole empire should march together in this
matter of the development of its resources, and that
this resolve should find expression in centralised action.
So far as the subject matter of this book is concerned,
we seem to need a great ‘‘ Imperial Department for the
development of the resources of the Empire, Section A,
Vegetable Products.” Such a department would
require a great service, and London should play an
important part in connection with the recruiting and
early training of the cadets. London has a great ad-

8 EXPLOITATION OF PLANTS

vantage for the purposes of a training ground, because
it alone is constantly visited by men on leave from the
distant parts of the empire. These men would be
temporarily attached to the central school, and they
could work up their results and give lectures and demon-
strations upon matters in which they had been inti-
mately engaged. As the cadets were passed out and
drafted to their jobs they would be liable to come in
contact with these same individuals, who would keep
an eye on them.

Such a self-feeding mechanism should promote a close
solidarity between all ranks, a fundamental condition
if such a service is to prove equal to the large oppor-
tunities awaiting it. The dominions, of course, are
wholly self-governing, and it is to be expected that they
will be eager to play a leading part in their own develop-
ment. At the same time, there is a good deal to be said
for an imperial corps with interchange between the
different parts of the empire; there must be many
problems in common, e. g. between South Africa and
Australia, and it would be a pity if the organisation
provided was isolated in separate compartments.

In this connection we might perhaps adapt the
American system to meet our requirements. There is
first the system of State Experimental Stations, where
the local problems are dealt with. Then there is the
great Department of Agriculture at Washington, with
its innumerable Bureaus. The personnel of this de-
partment is analogous in its working to the staff officers
of an army, whilst that of the stations may be com-
pared to the regimental officers in the field.

Applied to our case, the latter correspond to the

INTRODUCTION 9

existing staffs of the botanic gardens and agricultural
departments of the various dominions and other posses-
sions, whilst the equivalent of Washington would have
to be created in the form of the new Imperial Service,

- Were such a trained corps asked for with a guarantee
of work for cadets reaching an adequate proficiency,
there is little doubt it would be possible to provide
them (speaking for botany alone) at a rate of twenty or
even twenty-five a year. It is remarkable how quickly
good men and women of the best type begin to render
services of the highest value when put to work of this
kind.

When one recalls how much little countries like
Denmark do for their possessions, one is filled with
shame at our own backwardness. Botanists will be
familiar, for instance, with the Botany of the Faroé
Islands—a model of a complete monograph on the
flora, vegetation, economics and vegetable resources of
those islands.

Then take the case of Germany. Whatever the defects
of the German scheme of colonial development, it was
right in two respects. Germany did not hesitate to
take long views, and was content year after year to go
on spending large sums of money on her acquisitions ;
in the second place, their exploration was put in the
hands of qualified experts, and not left to the chance
visits of travellers and amateurs.

Probably no country in the world is more alive to its
responsibilities in these matters than the United States,
and'the provision made for the development of their
resources under the Department of Agriculture, to
which reference has already been made, merits the most

10 EXPLOITATION OF PLANTS

careful study at our hands. A feature which might
certainly be adopted by us with advantage is the issue
of a Year Book for general information ; thus bringing
under the covers of one volume a record in not too
technical language of progress in particular fields of
development in different parts of the empire.

We have seen how the first inspiration towards a
systematised botanical exploration of the empire origin-
ated atKew. Throughout its history no Government
establishment has served the empire more loyally and
impartially than has Kew, whilst men trained under it
are to be found in all the British dominions and pos-
sessions. With an organisation having such traditions
as one of our assets, the great task ahead should be
materially lightened so far, at any rate, as the develop-
ment of our botanical resources is concerned.

CHAPTER II

PLANT FOOD AND SOIL PROBLEMS

By W. B. BOTTOMLEY, M.A., Ph.D.
Professor of Botany in King’s College, London

THE importance of a knowledge of the conditions and
factors influencing plant growth is evident when one
considers the intimate connection between the profitable
exploitation of-plants and maximum crop production;

The living plant is a synthetic machine absorbing as
raw materials such substances as water, carbon dioxide,
nitrates, phosphates, etc., and manufacturing them into
‘various commercial products—foods (sugars, starches,
proteins), timber, fibres (cotton, linen), colouring matters
(dyes) and alkaloids (drugs)—and the value of any know-
ledge which enables the owner to run the machine
more economically or to increase its output cannot
be denied.

The soil is the source of all the raw materials, except-
ing carbon, and at first sight the problem of maintaining
or increasing the crop-producing power of any soil would
appear to be a simple one. Analyses of the ashes of
plants have shown that a certain few mineral substances
are always present in plants, and are essential to them as
nutrients. The importance of these has been amply

confirmed by water and sand cultures. Obviously these
It

12 EXPLOITATION OF PLANTS

mineral nutrients have been derived from the soil and
must be replaced when deficient.

The prevailing idea, until recently, regarding the
maintenance of soil fertility, was that each crop requires
certain mineral elements from the soil, and these must
be supplied by means of chemical fertilisers when they
are lacking or are present in insufficient quantities. ~

Recent research, however, has shown that this
“ mineral ” theory, which assumes that the fertility of
a soil or its crop-producing power is dependent only,
or even mainly, upon the mineral constituents which
it may contain, is far from complete.

The soil is not merely a reservoir for the mineral
nutrients of plants, but is the seat of complex physical,
chemical and biological actions which directly and
indirectly influence soil fertility. These actions are
intimately associated with the organic matter of the
soil and its bacterial inhabitants. Mineralogy and
inorganic chemistry, though helpful, are no longer
capable of solving soil problems. Biochemistry and
bacteriology, with their modern conceptions of colloids,
absorption phenomena, enzymes, oxidising, reducing
and catalytic actions, etc., are now rapidly extending
our knowledge of the soil as a medium for plant growth. .

Organic matter in the form of manure has been used
from earliest times for promoting plant growth, but
nothing definite was known as to its specific effect upon
plants. It was believed that it acted in some mysterious
way. Certain “ spirits ’’ were supposed to leave the
decaying manure, enter the plant and produce more
vigorous growth, leaving behind a leached substance of
a worthless nature. The trend of early ideas respecting

e)

PLANT FOOD re

the composition of organic matter is indicated by the
use of such terms as “ spirits of nitre’’ and “ spirits
of hartshorn,”’

During the seventeenth century, when the so-called
“nature philosophers ’’ were endeavouring to trace the
origin of living things to a “‘ first principle,”’ the search
for a principle of vegetation to account for the then
known facts about soil fertility and plant growth led
Van Helmont, about 1630, to state that he had found
this principle in water. From his experiments with
willow plants he concluded that water is transmuted in
some mysterious manner directly into plant tissue.

In 1650 Glauber suggested that saltpetre is the prin-
ciple of vegetation. Some years later Kulbel stated
that a magma unguinosum which is obtained from soil
humus must be regarded as the principle sought for.
Then in 1726 appeared the celebrated textbook of
chemistry by Boerhaave, in which he says that plants
absorb certain juices of the soil—the humus—and work
them up into food: The raw material, the prime
radical juice of vegetables, is a compound of fossil bodies
and putrefied parts of animals and vegetables. ‘* This,”
he says, ‘‘ we look upon as the chyle of the plant, being
found chiefly in the first order of vessels, viz. in the roots
and the body of the plant, which answers to the stomach
and intestines of an animal.”

Thus arose the old humus theory that plants derive
all their nourishment from the humus of the soil, and
this when exhausted was replenished by manuring with
dung and other organic matter.

This theory held the field for the next 150 years,
and it was not until the middle of last century that it

14 EXPLOITATION OF PLANTS

was replaced by Liebig’s famous mineral plant-food
theory. Liebig held that plants obtain their carbon
from the carbonic acid of the air, and their necessary
ash constituents from inorganic salts in the soil, and
soil fertility could be maintained solely by the addition
of mineral fertilisers.

This was a complete swing of the pendulum; from
organic food to solely inorganic, We are now learning
that neither theory was wholly right or wholly wrong.
There are certain fundamental truths in each of them.

Just at the period when Liebig’s researches were
thought to have finally solved the problem of plant
nutrition, there was arising a new science—bacteriology
—which was destined to play an important réle in all
questions relating to soil fertility. Studied at first.
chiefly in connection with infectious diseases, the new
knowledge was first applied to plant nutrition problems
by Schloesing and Muntz in 1877. ~

In the old humus days it had been held that “ cor-
ruption is the mother of vegetation,’ and even Liebig
taught that nitrogenous organic matter decayed in the
soil by a chemical process known as “‘ eremacausis,”’
with formation of ammonia, which was further con-
verted into a plant nutrient—nitrate. In 1877 Schloesing
and Muntz. showed that nitrification was due to the
action of bacteria, and in 1879 they claimed to have
isolated the specific organism. This last claim proved
to be erroneous, for Warrington in 1884 demonstrated
that nitrification consists of two processes—first the
production of nitrites, then their conversion into nitrates
—but it was not until 1899 that Winogradsky succeeded
in isolating the two kinds of bacteria concerned.

PLANT FOOD 15

The work of Schloesing and Muntz attracted a great
deal of attention, and soon there were a number of
workers in the field of soil bacteriology. Most striking
results were obtained in relation to the nitrogen cycle.
In 1886 Hellriegel and Wilfarth demonstrated the
presence of nitrogen-fixing bacteria in the root-nodules
of leguminous plants, and thus solved the problem of
the nitrogen nutrition of these plants. Another most
important discovery was the isolation by Beyerinck in
gor of a special group of nitrogen-fixing bacteria,
known as Azotobacter, which live free in the soil.
From the standpoint of crop production these organisms
possess great significance, for they are constantly adding
to the stock of available nitrogen in the soil by convert-
ing the atmospheric nitrogen into nitrogenous organic
matter.

The science of soil bacteriology has grown so rapidly
that the most recent textbook on the subject contains
goo pages. Over 300 species of the bacillus group,
and some 200 species of the bacterium group have been
isolated from soil.

In some quarters it is now held that the real makers
of plant food in the soil are bacteria, and they are
essential to the growth of all plants. At any rate, the
close connection between bacterial activity and the
nutrition of plants has been amply demonstrated by”
numerous experiments, and forms the basis of our
modern conception of the soil as a producer of crops.

How different now is our conception of soil from
what it was even thirty years ago. The term “ living
soil’’ is literally true. No longer is soil regarded as
a heterogeneous mixture of rock particles, clay and

16 EXPLOITATION OF PLANTS

organic matter serving simply as a trough for mineral
plant nutrients. We now think of it as a porous mass
made up of a skeleton of sand coated with a colloidal
mixture of clay and organic matter, which serves as a
nutrient medium for myriads of bacteria whose necessary
supplies of air and water are contained in its pores.
To quote Dr. E. J. Russell, “‘ Into the pores of this
mass we have no means of penetrating ; no microscope
has been devised that enables us to look into it and see
what is going on. . . . We shall find the study of the
soil very unsatisfying and uninspiring if we become too
much absorbed in its utilitarian aspects and forget to
stop and reflect on the infinite wonder of its honey-
combed structure and its dark recesses, inhabited by a
teeming population so near to us and yet so hopelessly
beyond our ken that we can only form the dimmest
picture of what the inhabitants are like and how they
live.”

But what is the work they do?’ Knowledge as to
this has been slowly accumulating during the last few
years, and we are learning that the all-important work
of the decay of animal and vegetable matter in the soil
is carried out through the agency of these bacteria.
This process is effected in several stages, and distinct
groups of bacteria are responsible for each stage. One
thing is certain, they are absolutely dependent for their
life and activities on the organic matter of the soil.
No soil can be truly fertile unless it contains organic
matter—humus material—as food for the bacteria which
bring about decomposition.

Hitherto attention has been directed chiefly towards
the organisms concerned in the nitrogen cycle in the

PLANT FOOD 17

soil. These fall into four chief groups—decomposers,
nitrifiers, denitrifiers, and nitrogen-fixers, and they
have: been investigated mainly from the point of view
of the total balance of nitrogen which they maintain in
the soil. Recent research, however, has shown that at
least equal importance attaches to certain intermediate
products formed by the decomposition bacteria which
not only influence the activities of other soil bacteria,
but also act directly upon plants growing in the soil.

For some years past an investigation into the nature
and composition of the organic matter of the soil from
the standpoint of biochemistry has been in progress
by the scientific staff of the Bureau of Soils department
of the United States Department of Agriculture. The
results already obtained have thrown considerable
additional light upom the question of soil fertility.
For example, Schreiner and Skinner have shown that
certain decomposition products of nucleo-proteins and
proteins, such as xanthine, guanine, creatinine, histidine
and auginine, which they have isolated from fertile soils,
can replace nitrates in a water culture solution and are
directly used in building up plant protein. This dis-
covery that beneficial organic decomposition compounds
exist in soils and play a prominent part in the life
processes of growing plants is of fundamental importance
in soil fertility.

The significance of the organic constituents of the
soil has not received the attention it deserves in this
country, and it is unfortunate that this promising field
of research has not attracted more workers.

For the last few years research has been in progress in
the Botanical Department of King’s College, London,

:

18 EXPLOITATION OF PLANTS

respecting the influence of certain decomposition pro-
ducts of organic matter upon the activities of soil
bacteria, and Professor Oliver has asked me to give a
short summary of the results obtained.

Krzemieniewski and others demonstrated some ten
years ago that soluble soil humates exercise a remarkable
stimulating action on the fixation of nitrogen by azoto-
bacter. As a result of a search made in 1912 to find a
material rich in soluble humates to serve as a medium
for the growth and distribution of these organisms,
it was discovered that when peat is incubated with
certain aerobic decomposition bacteria at a temperature
of 26° C. for a fortnight, a large proportion of the
humic acid present is converted into soluble humates,
and this material after sterilisation forms an excellent
nutrient medium for nitrogen-fixing bacteria. Tests
as to the manurial value of this “ bacterised peat ’’ made
at Kew Gardens and other places during 1913 showed

. that it contained a substance or substances which stimu-
lated plant growth to an extent which could not be
accounted for by the mineral nutrients present. This
suggested that the growth-stimulating properties of
bacterised peat might be due to the presence of organic
substances similar in nature to the accessory food bodies
or “ vitamines ’ concerned in animal nutrition.

As these accessory food substances are soluble in
water and in alcohol, and are further precipitated by
means of phosphotungstic acid, both aqueous and
alcoholic extracts and also a phosphotungstic acid frac-
tion were obtained from bacterised peat and were found
to have a stimulating effect both on nitrogen-fixing
bacteria and on plant seedlings grown in water cultures.

PLANT FOOD 19

The-results obtained with the plant seedlings were so
striking as to suggest the possibility that a certain amount
of organic matter in addition to mineral nutrients is
essential for the maximum growth of plants. As in the
usual water culture experiments with ordinary plant
seedlings a fairly large quantity of organic matter is sup-
plied to the young plant from the organic food reserve
of the seed, it was necessary to experiment with a plant
free from this objection. Lemna minor was eventually
selected as being suitable. Its normal habitat is water,
it multiplies rapidly by vegetative methods, and a reliable
estimate of variations of growth in different culture
solutions can be readily obtained by counting the plants
at regular intervals of time.

Preliminary experiments at King’s College during
1915 showed that Lemna minor plants fail to grow for
any length of time in a pure mineral culture solution,
but if certain extracts from bacterised peat be added
to the solution growth is normal and vigorous for an
indefinite period. These experiments were repeated
and extended last summer in the greenhouse laboratory
of the Imperial College of Science and Technology,
South Kensington.

Fifty culture dishes, each containing 250 c.c. of the
required solution, were prepared and arranged in five
series of ten dishes each. The solutions employed
were: Series I, Detmer’s standard culture solution ;
Series II, Detmer’s solution together with a water
extract of bacterised peat ; Series III, Detmer’s solution
with a similar extract freed from humic acid ; Series IV,
Detmer’s solution plus an alcoholic extract of bacterised
peat; Series V, Detmer’s solution with the addition of

20 EXPLOITATION OF PLANTS

the phosphotungstic acid fraction of bacterised peat.
The proportions of organic matter thus added in Series
II, III, IV and V were respectively only 368, 97, 32 and
13 parts per million of culture solution.

Twenty plants of Lemna minor, as nearly uniform as
possible in size, general healthiness and root develop-
ment, were counted out into each of the fifty dishes.
The solutions were changed twice each week, and
the plants in each dish were counted once every
week,

The plants in all the series multiplied fairly uniformly
for the first week, then the effect of the added organic
matter became very marked, until at the end of three
weeks the plants in Series II and III completely filled
their dishes. At this stage the plants in all fifty dishes
were halved, one-half being retained in the dish to con-
tinue the experiment, and the dry weight of the other
half estimated. This was repeated each week during
the continuation of the experiment.

The average figures obtained for the total number of
plants derived from the original twenty in each series,
and their total dry weight at the end of six weeks, are as
follows—

Series I. | Series IJ. | Series III. | Series IV. | Series V.

Number from original
BO pices ot cin seal teas
Dry Weight (in mg.)
‘from original 20 .| 17°6 II03 516 129 46

326 6723 3124 1100 483

The fact that successive fractionation of the extracts
obtained from bacterised peat resulted in a diminution

PLANT FOOD a1

of the effective growth-promoting substances present
is evident from the following comparison—

Series I. | Series II. | Series III. | Series IV. | Series V.

Organic matter added | — 368 97 32 13
Ratio of total number T 20°6 9°6 34 I'y
Ratio of total weight I 62°6 29°3 73 26

The effect of the reduction in amount of organic
matter with successive fractionation of the bacterised
peat was also manifest from the general appearance of
the plants. Those in mineral nutrients only decreased
in size week by week and became very unhealthy look-
ing, whilst there was a progressive improvement in
the appearance of the plants supplied with increasing
amounts of organic matter.

In view of these striking differences in general appear-
ance an examination was made of the internal structure
of representative plants from each set at the conclusion
of the experiment. It was found that in all the plants
receiving organic matter the tissues were more dense
and the proportion of air spaces to cellular tissue was
much less than in the control plants. The difference
was also very marked in the individual cells of the
respective plants. Those supplied with organic nutri-
ents were larger and more densely filled with proto-
plasm, and also contained larger nuclei and more
numerous chloroplastids. This difference was especially
noticeable in young newly-formed plants.

As it is well known that the ordinary distilled water
used in the laboratory often contains traces of toxic

22 EXPLOITATION OF PLANTS

substances, it was suggested that the beneficial effects
of the added organic matter might be due to a neutralisa-
tion of the toxicity of the distilled water used. Accord-
ingly a parallel series of experiments, using glass distilled
or ‘ conductivity’ water instead of ordinary distilled
water, was carried out. The figures obtained showed
that whilst the toxic substances in the ordinary distilled
water had a certain injurious effect upon the growth
of the plants, the use of pure non-toxic water will not
suffice for continued normal and healthy growth.

The necessity for the presence of certain organic
substances in a mineral culture solution in order to
ensure healthy growth is not peculiar to Lemna minor.
Experiments with Lemna major, Salvinia natans, Azolla
filiculoides and Limnobium stoloniferum, growing in both
Detmer’s and Knop’s culture solution, are equally
sensitive to the presence or absence of organic matter.

As the organic substances employed in the above
experiments were evidently decomposition products
of vépetable matter (peat),.experiments were made to
test to what extent similar growth-promoting substances
are present in other sources of decomposing vegetable
matter used for cultural purposes. Extracts of stable
manure, leaf-mould, and even a well-manured garden
soil were found to supply the beneficial growth-promot-
ing substances, although they are present in relatively
much smaller proportions than in bacterised peat.

The results thus obtained appear to justify the follow-
ing conclusions: (1) That bacterised peat contains
certain organic substances which, when supplied even
in small quantities to water plants growing in a com-
plete culture solution, have a remarkable effect upon

PLANT FOOD 23

their growth; (2) That in these plants normal growth
and multiplication cannot be sustained for any length
of time in the absence of these organic growth-promoting
substances ; (3) That these substances are essential
for the effective utilisation and assimilation of the
mineral nutrient supplied to the plants.

These conclusions are contrary to the generally
accepted botanical theory that green plants can build
up complex protein compounds from mineral salts and
mineral salts alone. Must we then consider these water
plants as exceptions to this theory, or must we modify
our present conceptions of plant nutrition ¢ Further ex-
periments alone can decide this. The well-known fact
that the seedlings of land plants can be grown to maturity
in water culture solutions of mineral salts is not a fatal
objection to the suggestion that all green plants may
require traces of certain organic substances for their
development, since it has been shown that such sub-
stances are produced during the germination ef seeds,
and the seedlings used in water culture experiments
may already contain the necessary minimal quantities
required for ordinary growth.

It is impossible as yet to state definitely how these
substances function. Some of them may be absorbed
and utilised directly as plant nutrients, whilst others
may have a similar effect to that of the accessory food
substances or growth vitamines concerned in animal
nutrition. Whatever may be the specific nature of
these organic decomposition products, they all have
the effect of promoting plant growth, and the term
“ auximone ” (adé:wos, promoting growth) has been
suggested as a general descriptive name for them.

24 EXPLOITATION OF PLANTS

No apology is needed, I think, for describing these
results in a lecture dealing with soil problems. Modern
research has shown the intimate relationship between
soil fertility and soil organic matter. For successful
crop production the soil must be supplied with humus-
forming material. Unfortunately, owing to the advent
of motor traction, one important source of such material
—stable manure—is rapidly diminishing. It has been
stated that during the last few years the omnibus com-
panies of London have dispensed with the use of 50,000
horses. This represents a loss to suburban growers of
250,000 to 500,000 tons of organic manure annually
from this source alone. All over the country there is
increasing difficulty in obtaining supplies of stable
manure, and some substitute will have to be found.
The experiments I have described point to the possi-
bility of utilising peat as an organic fertiliser. Raw
peat, owing to its acid nature and the toxic substances
it contains, is not only useless, but actually injurious to
plants. It has been shown above, however, that when
peat is “‘ bacterised ” its condition is altered, and it
then contains substances which have a remarkably
beneficial effect upon plant growth. There are un-
limited supplies of waste peat available in the United
Kingdom, and if only a portion of these could be treated
and rendered available as a cheap and effective plant
food, it would greatly assist the successful exploitation
of plants and benefit the whole community.

CHAPTER III

WASTE LANDS
By PROF, F. W. OLIVER

THE term Waste Lands is used here to designate
ground not exploited in an economic sense, or, at any
rate utilised only to avery slight degree. In the British
Isles the term may properly be applied to the following
terrains: sandy heaths, peat moors, sand dunes and
other maritime lands, including salt marshes and shingle
beaches, mountain talus, fen and artificial aggregates,
such as pit-heaps.

Before considering how some of these may be profit-
ably utilised or reclaimed, it may be well to state that
in the event of the adoption of a settled state policy of
reclamation, it would be necessary in some way to safe-
guard what is a great national asset, viz. the character-
istic and unparalleled beauty of English scenery. Sup-
pose, for instance, that the administering of such a
scheme were entrusted to a Waste Lands Commission
with statutory powers, it might be an instruction to
the Commission to leave untouched a large number of
reservations—analogous to the ‘‘ national parks” of
the United States. These would vary in size and form,
and also in the purpose for which they were intended.
Some would be quite extensive, like the Lake District,

25

26 EXPLOITATION OF PLANTS

others smaller and representative of the various cate-
gories. Sometimes the latter might with advantage
take the form of long belts left so as to screen and
diversify the exploited areas of the landscape.

Some proportion should be laid down between the
area to be reclaimed and that which should remain
inviolate, e. g. some such proportion as three to one or
four to one. In a matter of this kind expert advice
could no doubt be obtained from the Nature Reserves
Society and from the National Trust, both of which
bodies have accumulated experience; they might even
be asked to take over the guardianship of the reser-
vations. By analogous machinery the rights of
commoners might be guarded, and when interfered
with, compensation found.

The argument for reclaiming land on any consider-
able scale depends on the economic position. The
war has shown the peril of depending on overseas
trade for essential commodities to the great extent
that has obtained in the past. After the war we shall
be burdened with a vast debt, the bulk of the interest
on which will have to be raised internally. Money,
therefore, must be retained in the country and pro-
ductivity increased. This should be possible partly
by the adoption of higher standards of cultivation,
partly by the exploitation of areas hitherto neglected.
Thus in some measure we may hope to see imports
~ relatively restricted, money kept at home, and additional
rural occupations provided.

Lands remain waste, i.e. unproductive, from some
inherent physical or chemical defect, such as dryness,

WASTE LANDS a7

mobility, lack of some ingredient essential to plant
growth, or from toxicity ; they are also often neglected
through want of knowledge, inertia or deliberate intent.

Though much has been learnt in the last thirty or
forty years as to methods of ameliorating these obstinate
soils, especially in making good deficiencies by the
application of chemical fertilisers, this increase in know-
ledge has coincided with a down-grade movement in
agriculture in this country. Instead of being a question
as to what land should be taken in and reclaimed, it
has been much more a matter of what should be aban-
doned or laid down to grass. Largely as a consequence
of this adverse economic trend the problem of reclama-
tion of waste lands, under the climatic and other con-
ditions prevailing in the British Isles, is sadly in arrears.
Hence at its beginnings any scheme of reclamation must
be experimental, and only as experience accumulates
should the rate be accelerated.

In practice two methods have been applied in re-
clamation, viz. the bit by bit and the drastic. According
to the one the ground is cleared and broken up, drained
if necessary, perhaps limed, and then cropped in the
ordinary way. The process is long and tedious, and
the produce small: with perseverance, however, the
soil gradually acquires some fertility, and the reclama-
tion counts as a hard-won success.

The second and more modern method of reclama-
tion is characterised by supplementing the mechanical
operations by the addition of very large amounts of
chemical fertilisers with a view to making good defi-
ciencies in lime, potash, phosphoric acid and nitrogen.
Such treatment of the land involves an expenditure of

28 EXPLOITATION OF PLANTS

£5 or £6 per acre in the preliminary operations, charges
which often equal or exceed its original cost. Never-
theless, with intelligent handling the large expenditure
is found to be remunerative, and good crops accrue at
once. This type of reclamation may be illustrated by
the case of the East Anglian Breckland, a large area of
sandy heath of the most unpromising character.

SaNnpy HEaTHS

Breckland.—In reclamation, as in warfare, it is sound
strategy to attack the forces of the enemy where their
main strength is concentrated; if, therefore, the 400
square miles of N.W. Suffolk and S.W. Norfolk lying
to the north of Newmarket, and centred on Brandon
and Thetford, can be brought with profit to the plough,
it follows that other heathy and bracken-covered wastes
must yield to analogous treatment. Moreover, the
results of the very full investigations into the vegetation
of Breckland at the hands of Mr. E. P. Farrow (cf.
Journal of Ecology, vols. 4 and 5), give an admirable
picture of the nature of the difficulties which are being
surmounted with success in the reclaiming experiments
at Methwold, which Dr. Edwards, supported by the
Development Commission, has had in progress since
1914.

Breckland has a surface largely of sand, the remains
probably of sand dunes which once bordered the original
bay of the Wash. This sand, still liable to movement
by wind and much excavated by rabbits, overlies glacial
drift, and this in its turn the chalk. The rainfall is
one of the lowest in Britain, averaging 224 inches.

x

WASTE LANDS 29

Farrow, by means of a very simple experiment, has
shown in striking manner how the dryness of the soil
sets a limit to the vegetation. By allowing water to
drip continuously from the tap of a cask throughout the
growing season, it was found that the otherwise dwarf
grasses of the grass-heath association grew up with the
greatest luxuriance, in marked contrast with the stunted
vegetation round about. In order, therefore, to neutral-
ize the normal aridity of the soil, it is evident that the
water problem will require serious attention if crops
are to be raised profitably. Now there are three ways
in which more water can be put at the service of plants ;
(1) by increasing the rainfall ; (2) by irrigation ; (3) by
rendering the soil more water-holding, and so conserving
its moisture. No. (1) is out of the question ; irrigation
is not applicable in the present case, hence the soil
must be so treated as to increase its water content.
This is provided for in Dr. Edwards’s reclaiming
experiments by growing first a crop of lupins on the
cleaned and broken-up ground. This crop is turned
into the soil as a green manure, which not only adds
to the nitrogen content, but, by the humus it provides,
improves the water-holding powers of the soil. By
such means as these, combined with continuous tillage,
the water problem finds its solution. Dr. Edwards is
also an advocate of the practice of sowing thinly, by
which means the individual plants which constitute the
crop are more sturdy and deeper rooted than is the case
with denser sowing, whilst an equal or greater output
is obtained.

The preliminaries to cultivating Breckland include
in addition to clearing and breaking up the surface the

30 EXPLOITATION OF PLANTS

addition of large amounts of manures in the form of
chalk, basic slag or crushed bones and kainit with
nitrate of soda or sulphate of ammonia, according to
the crop. These preliminary operations, representing
charges of about £5 an acre, were more than met by the
returns from the crops produced, that is to say, the
value of the produce not only paid for its cultivation,
but was sufficient to meet the higher rental correspond-
ing to the larger capital expenditure. For details of the
experiment, see P. Anderson Graham’s Reclaiming the
Waste, chap. ii-vi.

Though Dr. Edwards’s reclamation has been limited
to a comparatively small area (150-160 acres), there is
no inherent reason why similar methods should not be
pursued on a much larger scale, both here and on
other sterile sandy heaths.

Whilst the arable cultivation of Breckland and other
sandy heaths would thus appear to be remunerative
propositions, there is another way in which this class
of ground can be utilised. Breckland produces pines
and so do the Bagshot sands and other areas of the kind.
Mr. Farrow, indeed, holds the view that Breckland was
formerly forest land, and that its primary economic use
is to be once more afforested.

Any scheme of national security must include not
only the home production of food stuffs, and especially
cereals, but also of timber. As I understand Mr.
Farrow’s- view, sandy heaths like Breckland should
only be ploughed up.in the event of the minimum
requirements of forestry being satisfied by rough ground
which cannot be cultivated in any other way. If the
safety-line in cereals can be reached by ploughing up

WASTE LANDS 31

grass land alone, then Breckland should carry trees.
A decision without full data is very difficult, and
ought not to be made hastily.

A further alternative is also possible, viz. that these
areas should be partly afforested and partly converted
into tillage. This method has two advantages. The
woodlands would give shelter to the ploughed-up land,
and they would also guarantee work in winter for the
farm labourers, thus providing the countryside with
another useful bulwark. If the view repeatedly ex-
pressed in recent discussions be well founded, viz.
that a closer entente between forestry and agriculture
is necessary for the success of both, there would
seem to be a reasonable probability that a division of
Breckland on these lines might prove to be the best
economic policy to pursue.

So far as sandy heaths are concerned, there can be
no doubt whatever of their amenability to profitable -
reclamation alike for tillage and forestry. This has been
firmly established on the continent of Europe, and
nowhere more convincingly than in the Netherlands.
The peoples of the Low Countries are the world’s:
pioneers in reclamation work. In England, and
especially in East Anglia, we have in the past been much
beholden to the Dutch in showing us how to drain and
utilise our fen lands and salt marshes ; whilst in times
still more remote, the Prussians received instruction
from the same source. When Albert the Bear over-
came the Wends about the year 1170, he peopled
Brandenburg with refugees from Holland whom the
overrunning of the Zuider Zee had rendered homeless.
These were ‘‘ men thrown out of work who knew how to

32 EXPLOITATION OF PLANTS

deal with bog and sand, by mixing and delving, and
who first taught Brandenburg what greenness and cow
pasture was.”"} Full details of the various types of
reclamation practised by the Dutch are to be found
in J. W. Robertson-Scott’s War-time and Peace in
Holland, Heinemann, 1914.

THe AFFORESTATION OF PIT-HEAPS

Before passing on to consider the utilisation of other
types of waste land, reference must be made to a very
successful scheme for the afforestation of the waste
heaps of pits in the Midlands. The area exploited is
the Black Country which coincides with the South
Staffordshire Coalfield. It has the peculiarity, owing
to its shallow surface workings, that the pit-heaps are
widely spread and cover much ground, thus contrasting
with deep level coalfields where the waste is concen-
trated in much higher mounds near the shafts by which
the coal is won.

The area of these heaps in the Black Country has
been estimated at 14,000 acres, but it may exceed this
figure considerably. A beginning was made in 1904,
when an organisation known as the Midland Re-afforest-
ing Association, founded for the purpose, began planting
experimental and demonstration areas. In some cases
the planting was done for private owners, in others
on ground leased by the Association. The work has
gone steadily forward, thirty-five experimental areas
have been established, together with one large one of
thirty to forty acres at Bilston.

1 Carlyle’s Frederick the Great, 1st edition, vol. i. p. 94.

WASTE LANDS 33

The soils afforested are principally of two types,
viz. shale or “‘ clunch,’”’ and carbonaceous shale, which,
as it contains much coal slack, is apt to fire and burn
into a friable red soil. The cultivation is of the simplest.
Pits are dug one spit deep, the surface vegetation is
placed at the bottom and the young tree filled in. The
labour has been of the casual type, and has proved
quite satisfactory. The cost of planting averages £6
per acre, with about ts. per linear yard for fencing (1742
trees per acre, i. e. five feet apart).

The most successful of the trees planted include the
alders (Alnus glutinosa and A. incana), black poplar,
sycamore, willows, wych elm, birch and robinia.
Plantations dating from 1904-1908 are now eighteen to
twenty-four feet in height, whilst black poplars which
surround some of the plantations have reached a height
of thirty feet. The impression created on the mind by
a visit to these afforested pit-mounds is a very agreeable
one indeed, the dirt and desolation everywhere throwing
into strong relief these bosky woodlands, which in ful-
ness of time will doubtless extend through the length
and breadth of the Black Country. A very great merit
of this scheme is its conception on genuine forester’s
principles. The enterprise is no mere plan for tidying
up and beautifying the district—laudable though such
would be—but a definite and successful effort to grow
trees for profit. The district round about is hungry
for small timber. Thus birch and alder fetch good
prices for making handles for the innumerable objects
produced in the locality, whilst poplar is in demand
for brake-blocks.

The moving spirit in the affairs of the Association

D

34. EXPLOITATION OF PLANTS

is Mr. P. E. Martineau. His principal criticism of the
earlier plantings is that they would have been better
with the trees at four feet instead of five feet intervals
(i. e. 2722 in place of 1742 per acre), especially on wind-
swept areas. Future developments will doubtless con-
form to experience in this matter. It is to be hoped
and expected that other coalfields may follow the lead
of the Midlands Association in the period of recon-
struction after the war.

MariTIMeE WASTES

By the sea shore products of erosion accumulate in
the form of sand dunes, shingle beaches and salt
marshes, terrains the possibilities of which have been
_ too long neglected in this country.

1. Sand dunes—These attain their fullest develop-
ment in Gascony, along the Bay of Biscay, in North
Holland, and in Baltic Prussia. Owing to their extent
and to their great capacity to ‘‘ wander ’’ before the
prevalent winds, the dunes of these regions have been
very fully studied for more than a century, and the
technique of their fixation by means of vegetation has
reached a high degree of perfection. They are fixed
partly by planting Psamma (marram grass), partly by
afforestation, especially with coniferous trees. In
Gascony productive forests of Pinus Pinaster have arisen,
whilst on the Baltic a variety of coniferous and broad-
leaved trees are employed. In Gascony the pinasters
are exploited for their turpentine, and when they have
run dry they are felled to provide pit timber, largely for
the South Wales Coalfield.

WASTE LANDS 35

Experiments at Holkham in Norfolk, and later at
Formby on the great dune area near Southport, have
shown that English sand dunes can be afforested with
pine trees in a perfectly satisfactory manner.

The Holkham plantations, which cover 500-600 acres
of sand hills parallel to the shore, date more than forty
years back, and consist of Austrian (P. nigra) and
Corsican (P. Laricio) pines, together with some amount
of Scots pine (P. sylvestris). From a forester’s point
of view these woods were not planted quite close
,enough—being intended rather for shelter and to im-
prove the amenities of the estate than for profit.
Nevertheless, by natural regeneration the Holkham
plantations are becoming denser, and should if required
provide saleable timber.

It is to be hoped in any scheme of afforestation the
utilisation of our sand dunes may be seriously con-
sidered. Rabbits are the bane of dune planting, and
for success these must be exterminated or held in
check.

Another possibility in the way of dune exploitation
is the improved cultivation of Psamma (marram grass).
Paper experts have reported very favourably on the
prospects of marram as a raw material for the manu-
facture of paper,! though it does not appear to have
been exploited commercially in this sense hitherto.
The fibre obtained belongs to the same class as that of
esparto grass, and can be dealt with in the mills where
esparto is treated. Before the war we imported some
200,000 tons of esparto grass from Southern Spain and

1 Kew Bulletin of Miscellaneous Information, 1g1a, p. 396; 1913,
p- 363.

36 EXPLOITATION OF PLANTS

the North African Coast at a cost to the paper manu-
facturer of £3 tos. the ton.

Experiment will have to determine how often an
area can be cut, the most economical distribution
of shelter belts so that the sand shall not blow away
from the stubble, the effects of manures, and the
possibility of using reaping machinery on ground of
this kind.

For a maximum output it will be necessary to plant
the dunes with marram, an operation well understood
and costing, where the most approved methods are
followed, according to Gerhardt’s estimate £4 per
acre, and according to the Australian exploitation at
Port Fairy, Victoria, £4 5s.—all charges included.
The subsequent details for regular cropping would
have, of course, to be ascertained by trial.

In addition to the above, sand dunes lend themselves
to a variety of cultivations. Thus the bulb gardens of
Holland consist of a thin layer of dune sand overlying
peat; where the sand is too deep canals are cut and
the sand removed in barges till reduced to the required
thickness. No doubt quite suitable areas for bulb
gardening are available in England; nevertheless, it
would require an heroic effort to compete with the
Dutch in this highly technical art, for it must be remem-
bered that bulb culture suits the Dutch genius, and
that they have had centuries of experience in the craft.

Vegetables can be very successfully raised on dune
sand, The writer vividly remembers the supreme
excellence of vegetables, and especially of potatoes, from
a dune garden in Brittany which had been tempered
with mud from an adjacent salt marsh.

WASTE LANDS 37

2. Shingle beaches——England is rich in shingle
beaches. For the most part these are narrow strips
of pebbles protecting low-lying ground from the sea.
The principal use of these is defensive, and to ensure
them from being breached or overrun by high tides
they should be fixed by suitable planting.

In certain cases, as at Orfordness, Rye, and notably
at Dungeness, enormous areas of shingle are deposited,
often covering many square miles. Such aggregates
are termed apposition beaches from the successive strips
or unit beaches lying side by side that compose them.
Cut off from the sea, the inner beaches are apt to remain
sterile for long periods, largely because the sea no longer
gaining access, they are deprived of sea-borne seeds to
colonise them and of the vegetable drift to form a
humus soil.

It has often occurred to the writer that these areas
might be turned to some account by afforestation, For
that purpose it would be necessary in the first instance
to sow nurse plants, such as gorse and white alders
(Alnus incana), which, possessing nitrogen fixing root
tubercles, would at the same time enrich the soil.
These would be followed by the planting of trees—
the most suitable species for the purpose would have
to be ascertained by experiment, as there exists no
experience to guide us.

3. Salt marshes ——The value of these for reclaiming
by banking out the sea is well known and requires no
emphasis here. On the East Coast especially much
ground was won formerly in this way, though since the
fall in agricultural prices there has been no inducement
to risk the large investment of capital which these

38 EXPLOITATION OF PLANTS

intakes demand. With higher prices the position is
altered, and, should there be a reasonable probability
of their continuance, no doubt the reclaiming of salt
marshes will once more receive attention. .

In the past not a few of the reclamations, especially
in estuaries and harbours, have been imprudently made
with serious results to the navigation. The decayed
ports of the north coast of Norfolk are outstanding
examples. No operation is more tempting than to
bank off the head of an estuary and to convert it into
rich pasture or tillage. But in so doing the fact is too
often lost sight of that the capacity of the estuary for
storing tidal water is seriously impaired, and in par-
ticular it is robbed of just that storage space which holds
the water that flows away relatively late in the ebb,
and has the greatest effect in scouring the channel at
the outlet. Deprived of this natural means of clearing
the mouth, silt gradually works up channel and raises
the level of the bottom, with the inevitable consequence
that navigation is seriously compromised. For the
sake of a few hundreds or even thousands of acres of
new land it is hardly worth while to destroy a port,
for, after all, our maritime facilities must remain one of
our greatest assets.

Much less risk of silting up is incurred when the
sides of an estuary are banked off by longitudinal works,
whilst the scour of the ebb can be concentrated at
the effective place by means of training walls. These
operations, however, belong to the province of the
maritime engineer rather than to that of the botanist.
Ecological investigations show that the botanist has a
field_of usefulness in such operations in speeding up

WASTE LANDS 39

the vegetation phases on the mud flats before the pro-
posed intake is sufficiently advanced for banking. On
mud flats, as elsewhere, the vegetation shows “ succes-
sions ’” which are subject to delays, owing sometimes to
lack of seed of the plants of the next phase, sometimes
to mobility of ground or other cause. By close study
of these successions it is easy to recognise when a given
phase is overdue, and its appearance could doubtless be
accelerated by sowing seeds or by treating the ground
in some appropriate way.

On the other hand, we deepen navigable rivers by
dredging, and the sludge is commonly taken out to sea
in barges and dumped. Thus at the mouth of the
Thames we dispose in this way of enough mud in a single
year to raise the level of 1000 acres of the low-lying
shore by as much as three feet. On the tidal reaches
of the Seine such materials are carried over the banks
and used to level up low marshy ground, rendering it
suitable for agriculture and tillage. Is there any reason
for this divergence in procedure ¢

UTILISATION OF NATURAL PRopUCTS OF SALT MarsHEs

Before leaving the subject of the salt marsh, there
is the possibility of direct utilisation in contradistinc-
tion to reclamation. The species of plants that flourish
on tidal marshes are, as is well known, limited in
number; not more than 1} per cent. of all British
plants are halophytes, and this, of course, circumscribes
the possibilities of utilisation. _ 4

There is, however, on the South Coast a plant which

40 EXPLOITATION OF PLANTS

has latterly appeared in enormous quantities on the
mud flats of Southampton Water and Poole Harbour,
and which is certain to penetrate into other areas.
Public attention was first directed to the spread of
Spartina Townsendii (“rice grass”) some ten years
ago by Lord Montagu of Beaulieu, and a good deal of
precise information as to the plant has been made
available by Dr. O. Stapf. Spartina now occupies
thousands of acres of mud flats in the areas named,
and is still rapidly spreading—particularly in. Poole
Harbour, where it was first detected in 1899. Its
original appearance in the waters of Southampton dates
back about fifty years, and it is presumed to be a natural
hybrid between the indigenous species Spartina stricta
and a supposed introduction from America, Spartina
alterniflora, recorded early last century.

At first Spartina Townsendii was an isolated botanical
curiosity. A shy seeder, it penetrated slowly to new
centres. Its vegetative power is remarkable, however,
and the seedlings by spread of rhizomes deep in the
mud, grow into clumps, and in time the neighbouring
clumps unite into pure, continuous meadows. By
occasional seeding and water carriage new areas are
systematically invaded, and then as the grass gets a
hold it rapidly covers the higher mud flats to the
practical exclusion of other vegetation.

Hitherto this miracle of Nature, which is transforming
the waters it occupies, has been put to no definite use,
that is to say it has not been exploited.

It has been tried, in a small way, at various places
as an agent in promoting reclamation in virtue of its
powers of holding silt. And no doubt on suitable

WASTE LANDS 4I

ground, under a congenial climate, it will make its
mark in this capacity.

On certain parts of Poole Harbour, where the ground
has been sufficiently consolidated, cattle go down on
to the marshes to feed on it, but so far as we know its
feeding value still awaits investigation by critical trials.

Since the war a sample has been submitted to a
paper expert who reported favourably on the qualities
of its fibre, and at the present time Spartina is
undergoing trials at the hands of paper manufacturers.
Spartina undoubtedly possesses good qualities from this
point of view, but the difficulty of its habitat will have
to be overcome before commercial success can be
attained.

These difficulties are probably novel in the exploita-
tion of any plant. Spartina grows on very soft, sticky
mud, and is covered by the high tide twice a day.
The problem is to cut the grass, to keep it from being
sullied by the mud, and to get it ashore and spread out
to dry before the next tide rises. If these operations
are to be done by hand, the reapers will have to be
very highly trained, as mud on the leaves and stalks is
most difficult to remove, and makes black specks in
the paper.- Hitherto cutting by machinery has not
been tried, nor will it be till the conclusion of the war,
for the paper industry is hardly to be reckoned an
“ essential trade.”’

The above examples may serve to illustrate the
possibilities of utilisation of waste lands by the sea.
They indicate the existence of a considerable field well
deserving a closer investigation than it has yet received.

42 EXPLOITATION OF PLANTS

The time is probably ripe for the preparation of a much
fuller survey and report of this type of ground than
has hitherto been considered necessary. And what is
true of maritime wastes applies with equal force to other
types. Towards the realisation of these objects there
seems room for a ‘‘ Waste Lands Commission ”’ pro-
vided with very considerable powers of initiative ; to
such a body would also fall the task of guarding public
rights, especially those of commonage. Into the details
of organisation, however, space does not permit us to
embark.

REFERENCES

Lorp EvEerRsLEY. Commons, Forests and Footpaths. Cassell & Co.,
1910.

The Midland Re-afforesting Association. Reports, 1903-16.

The Utilisation and Improvement of Waste Lands. British Association
Report, Sec. K, 1916.

J. Bert. Les dunes de Gascogne. Paris, 1900.

P, GERHARDT. Diinenbau. Berlin, 1900,

W.H. WHEELER. The Sea Coast. Longmans, Green & Co., 1903.

P. ANDERSON GRAHAM. Reclaiming the Waste. Country Life, 1916.

CHAPTER IV

TIMBER PRODUCTION IN BRITAIN

By E. J. SALISBURY, D.Sc., F.L.S.
Lecturer in Botany at the East London College

THE national importance of an adequate supply of
home-grown timber has been very cogently brought
before us during the present war. It can scarcely be
gainsaid that for the future it is extremely desirable
that in times of stress we should be independent of sea-
borne supplies for our minimal requirements. But
apart from the utilisation of timber in its unconverted
form, the maintenance of sufficient home provision
would both encourage and create the numerous asso-
ciated industries which depend upon forests for their
raw material. Not only would these produce an in-
crease of employment, but, what is perhaps even more
to be desired, would tend to retain permanently the rural
population in country districts, and thus maintain a
more equable distribution of labour.

The value of forests in regulating water supply has
long been recognised, and the planting of water catch-
ment areas might profitably be undertaken on a much
larger scale than heretofore. The example of Birming-
ham, Leeds and Liverpool in this direction is one which
might well be followed by other municipalities.

43

44 EXPLOITATION OF PLANTS

For purposes of protection against erosion and
denudation, forests are also of the greatest utility.

Without labouring the theme, it will be realised that
apart from the value to the nation of sufficient home-
grown timber, the forests that produced that timber
would subserve national interests of the first importance.

In spite, however, of the undoubted value of forests
to this country, it cannot be said that in the past they
have, generally speaking, been a success, either from
the financial aspect ‘or from the point of view of the
timber produced.

I propose, therefore, even at the risk of recapitulating
much that has already been said or written elsewhere,
briefly to review what are probably the chief causes
which have led to failure in so many cases.

There are certain factors which materially affect the
financial aspect of timber production, and which are
more or less external though none the less fundamental,
Such are cost of labour, cost of transport, and foreign
competition.

These are matters with which I have no special
qualification for dealing, but in reference to foreign
competition it cannot be too often urged that timber
producers in this country undoubtedly labour under
a great disadvantage. Evidence brought before the
Royal Commission in 1908 showed that in effect there
is a preferential tariff for the carriage of imported
timber. The extent of this has sometimes been exag-
gerated, but it undoubtedly operates very adversely
against the home production of unconverted timber
such as pitwood, scaffold poles, etc.

A still more serious consideration is that in effect

TIMBER PRODUCTION 45

imported timber, paradoxical as it may sound, is placed
upon our markets at under cost price. This is due to
the fact that the imported timber is nearly all the pro-
duce of virgin forests on which, of course, there is no
accumulated debt representing compound interest on the
cost of establishment and maintenance. The low price
of foreign timber is thus largely maintained at the
expense of the national capital of the exporting country.

Now the major part of the expenses of establishment
of a timber crop are paid in wages, so that most of what
is gained by the low price we pay for imported wood
we lose in home labour. It is therefore a matter for
careful consideration whether it is not in the national
interests to place an import duty of equivalent value on
all timber which conditions of soil and climate admit of
being produced at home. Iam fully aware of the con-
troversial character of such suggestions, associated as
they unfortunately are with certain political creeds,
but those most competent to judge warn us that the
virgin forests are rapidly becoming depleted. If,
therefore, no steps be taken to encourage home pro-
duction, we shall be faced in the near future with the
necessity of paying a higher price for foreign timber
than would at the present time show a profit on home
produce, without the commensurate advantage of
forests of our own to meet the growing demand, and
to provide labour for our own countrymen.

Apart from the foregoing fundamental adverse con-
ditions, there are many internal and remediable factors,
a reform in respect to which would materially affect
the financial aspect.

Understocking.—Probably one of the most adverse

46 EXPLOITATION OF PLANTS

factors tending towards the failure of economic forestry
in this country is the inferior quality of the timber
produced. This is due in a very large degree to the
fact that most of our forests are too open in character.
This feature is probably largely a result of the fact
that in past generations the English oakwoods were
the source of supply for the oak used in shipbuilding.
For this purpose the crooked branches were highly
valued for the making of the ribs and knees. Open
canopy favoured the production of large, strong, and
numerous branches such as the shipwrights required.

Many of our woods of common oak were planted
shortly after the Parliamentary Commission report
early in the nineteenth century, when a famine in wood
for naval construction was anticipated. With the in-
troduction of iron for shipbuilding about 1836, the
demand for bent oak rapidly decreased, so that at the
present day we have in this country a considerable
quantity of common oak in a mature-condition which
was grown for a specific demand that no longer exists,
Unfortunately the very method of growth which was
most advantageous for the purposes of the shipwright
is least suited to modern requirements.

The demand at the present day is for clean, straight
poles, with straight grain and uniform annual rings.

The defects which result from understocking may
be summarised as follows—

The growth is too rapid, and results in an uneven-
ness of grain which renders the wood less durable and
of variable strength.

The open canopy permits each tree to produce a
large mass of foliage, and to meet the demands of

TIMBER PRODUCTION 47

transpiration a large number of vessels are consequently
formed each spring. In a well-stocked wood the
canopy of each tree is much reduced, and the propor-
tion of vessels to fibres in the spring wood is much
smaller. Consequently the timber produced is of
greater strength.

The boles.in open canopy tend to be short and taper
rapidly, so that not only is the gross amount of timber
in the trunk small, but also in order to obtain planks
of adequate length there is far more wastage than in a
long trunk which tapers slowly.

By far the most serious defect, however, is the early
production of numerous strong branches, so that the
trunk is knotty and largely consists of faulty wood.

Since the practice is for the landowner to sell the
trees standing to some timber merchant, it will be

evident that the latter, even in the case of well-grown

trees, accepts a certain risk in respect to the quality of
the timber. It is scarcely surprising, therefore, that
much of the oak growing in this country at the present
day is practically unsaleable.

In view of the many adverse conditions, we are
certainly not justified in forming an estimate of the
economic soundness of British forestry on the basis
of the financial results which the average present-day
woodland yields. This is emphasised when we remem-
ber that the understocking itself, apart from the corre-
lated effects, considerably reduces the increment value
of the forest.

The extent of the understocking can best be illustrated
by afew figures. We may take it that a properly stocked
oakwood between 100 and 120 years old should have

48 EXPLOITATION OF PLANTS

not less than 100 trees to the acre. In actual fact a
large majority of the oakwoods in the southern part
of England have less than 30 trees to the acre at
maturity.

Open Canopy and Game Preservation —We have seen
that the historical factor has played a large part in
determining the open character of our woodlands, but
another practice; and one far more difficult to remedy,
is the influence of sport.

A high forest properly stocked usually exhibits a very
sparse shrub layer and scarcely any herbaceous flora.
Such woods, therefore, present very poor cover for
ground game and pheasants, so that financial success is
all too frequently sacrificed to the demands of pleasure.
The widespread character of coppice with standards is
probably due to the fact that it constituted a compromise
between the diétates of forestry and those of sport.

Under modern conditions, however, this system
rarely produces satisfactory financial results. An ex-
ception to this generalisation must be made where the
coppice supplies the demands of some local industry,
as, for example, around Haselmere, where the chestnut
coppice is utilised for fencing, and realises from £6 to
£18 per acre in a fifteen years’ rotation.

Much might be done towards reconciliation of the
forester and gamekeeper by suitable underplanting with
covert shrubs, such as yew, box, laurel, etc. The use
of Rhododendron for this purpose in the past has, per-
haps, brought the system into disrepute. For where
the soil is suited to this plant it often exhibits such
luxuriant growth and seeds so freely as to constitute
an impassable barrier to the beaters.

TIMBER PRODUCTION 49

One great defect of the coppice with standards is the
enormous increase in the ground flora after coppicing,
with consequent impoverishment of soil, particularly
by breakdown of the humus.

Rabbits—In quite a number of woods upon the
lighter soils rabbits flourish and multiply to an in-
ordinate degree, and there can be little doubt that the
paucity of self-sown seedlings of our forest trees can
in most cases be laid to their charge. It cannot be too
strongly emphasised that rabbits and good forestry
cannot go together. This fundamental fact must be
realised if our British woodlands are to be improved.

No one who has carefully examined any large area
. of coppice can fail to have noticed the common tendency
toward degeneration, even where the stools are horn-
beam with its proverbial longevity. There are in the
oak-hornbeam woods of Hertfordshire many hundreds
of acres where there is scarcely a living stool, and the
soil is being exhausted by a rank growth of brambles.
This condition, there is good reason to believe, has been
brought ‘about almost entirely by the depredations of
rabbits, which nibble off the sprouting shoots that
appear after coppicing. A systematic destruction of
these animals would not only result in a much smaller
accumulated debt consequent upon the saving in wire
netting, but in all probability the large number of
seedlings surviving would make it possible to regenerate
disafforested areas by natural means. If rabbit fences
could be dispensed with, the saving effected would
represent between £1 10s. and £2 per acre, or an ac-
cumulated debt, reckoned at 4 per cent. on a hundred
years’ rotation, of from £76 to £101. Viewed from

E

50 EXPLOITATION OF PLANTS

another aspect, it would represent an increased annual
rental of from 1s. 2d. to 1s. 74d. per acre.

Reform in policy.—We can summarise the necessary
reforms in policy as follows—

1. Much denser planting.
2. Subordination of the gamekeeper to the forester.
3. Extermination of rabbits in afforested areas.

To these may be added increase in size of the
afforested areas. The tendency to form numerous
small woods has been largely owing to the dictates of
sport. By increasing the area of contiguous wood-
land many advantages would accrue.

Firstly, it would render possible the construction of
good forest roads, thereby reducing the cost of transport;
moreover, the utilisation of motor lorries would under
these conditions become feasible. Large areas produce
a constant supply of timber, so that the erection of plant
for dependent industries becomes economically possible,
and where considerable supplies are available, the cost
of local conversion is more than compensated for by
the diminution in the cost of transit.

I now come to that part of my subject with which I
propose to deal more fully, viz. the importance of
ecological research to practical forestry. It may be
said of forestry that much of the present practice is
purely empirical and not based. on sound scientific
principles.

One only has to glance through~any textbook on
forestry and read the conditions given as suitable for
the growth of different forest trees, to realise how vague

ue

TIMBER PRODUCTION 51

is the information regarding the requirements of the
various species,

Recent ecological research on the distribution of
natural woodland types has done much towards placing
our information on this subject on a sounder basis.
For it may be fairly argued that if a particular species
of tree forms pure woods on a particular type of soil
under the stress of natural competition, that same tree
will grow, at all events, no less vigorously when the
struggle with other species is eliminated by artificial
protection.

To illustrate the value that ecological work may have
in this direction, I cannot do better than quote an
example that has come prominently under my notice
during the last ten years. There are in this country
two native species of oak, viz. the common oak (Quercus
robur) and the durmast oak (Q. sessiliflora). In many
of the older works on forestry the distinction between
these two was either ignored, or if recognised was not
made the basis for any distinction of treatment. In the
more modern and better works the two are usually
stated to require the same cultural conditions.

One is indeed led to assume that in general it is of
no consequence which species is planted either on
account of the soil conditions or the timber produced,

The study of plant communities has led to the real-
isation that marked preferences as to soil and situation
are often far more pronounced between closely allied
species than in those which are wholly unrelated. And
perhaps in no case is this more striking than in the
natural distribution of the two native oaks as brought
to light by the ecological work of recent years.

52 EXPLOITATION OF PLANTS

_ Thus Moss found that in the Peak District there was
a sharp distinction between the areas occupied by the
common and durmast oaks. There the common oak
is met with growing on deep, non-calcareous, fluvio-
glacial sands, whilst the durmast oak is restricted to
the shallow soils overlying the siliceous rocks. The
same investigator found the common oak forming wood-
lands in Somerset on the deep sands of the greensand
-- series, and on the deep calcareous marls. Adamson
in Cambridgeshire found the common oak both on
calcareous marl and loam.

In Hertfordshire the common oak is entirely con-
fined to the stiff clays and heavier loams, whilst the
durmast oak is restricted to the lighter loams and
sands or soils deficient in lime.

In upland districts the durmast oak forms extensive
woods on the shallow soils overlying the non-calcareous
and sometimes calcareous rocks of the steep valley
sides.

Thus we find woods of Q. sessiliflora on the lower
estuarine sandstones of the superior oolite of Yorkshire,
on the Devonian sandstones of Somerset, and on the
Cambrian and Silurian rocks of Wales, such woods
often extending to an altitude of 1000 feet.

Although we are far from having entirely solved the
problem of the respective habitats of the two species,
it is clear that the vague statements of foresters in
the past have not merely been misleading, but often
positively erroneous.

Thus it is evident that except in districts where the
rainfall is exceptionally high, the durmast oak does
not naturally occur on calcareous soils, whilst the

TIMBER PRODUCTION 53

common oak flourishes in heavy soils of this character
when of sufficient depth. On non-calcareous soils the
common oak is restricted to the heavier and the durmast
oak to the lighter soils. But the outstanding feature
elicited by a study of the distribution is that deep soils
are only necessary for the common oak, whilst the other
species flourishes on relatively shallow soils where,
moreover, it produces quite good timber.

From an investigation upon which the writer is
engaged at the present time, I believe it will also prove
to be a fact that whereas Quercus robur requires a soil
relatively rich in mineral salts, Quercus sessiliflora grows
well in soils which are relatively deficient in this respect.

It is by no means infrequent to find plantations of
Quercus robur on light soils to which it is quite unsuited,
as also on shallow soils where it grows for a time but
afterwards becomes stunted.

The question naturally arises as to whether there is
any difference in the quality and properties of the
timber produced.

The sp. gr. of the wood of Q. sessiliflora is slightly
higher than that of Q. robur, and, though the available

data are somewhat conflicting (doubtless owing to
confusion of the species), it seems evident that for
durability and strength the wood of Q. sessiliflora is
preferable to that of Q. robur. Moreover, the grain
of the common oak is not so even and consequently
harder to work than that of the durmast oak.

A very important difference is that whereas Q. robur
tends to produce a short bole with numerous strong
branches, the durmast oak usually, even when grown
in open canopy, forms‘a long straight bole with weak

54 EXPLOITATION OF PLANTS

lateral branches. This natural tendency renders the
durmast oak particularly suited for planting as high
forest with coppice. Moreover, as it is not necessary
to plant it so close as the common oak in order to pro-
duce good quality wood, the amenities of the game
covert can be preserved without diminishing the value
of the timber.

It is significant in this connection that the timber
from a certain wood in Hertfordshire in which the oak
is almost exclusively Q. sessiliflora, realises nearly twice
the price of that from the surrounding woods where
Q. robur is the predominant tree.

Owing to the long period that must elapse between
the seedling stage and the mature tree, the experi-
mental method so largely adopted in agriculture is only
to a very limited extent applicable to forestry. As a
consequence the ecological method of investigating the
natural conditions as they occur in the field, and cor-
relating them with the quality of timber produced,
offers the best avenue for an increase in our exact
knowledge of the factors governing timber formation.

Data of inestimable value to the forester are being
slowly accumulated by the ecologist. As, for example,
accurate determinations of the acidity, water content,
and mineral salts present in the soils of different types
of woodlands.

But apart from information of this character, there is
another line of research which the ecologist has opened
up, and which in co-operation with the practical forester
should yield fruitful results. I refer to the association
of species. There is little doubt that in the past we
have been too much influenced by the German tradition

TIMBER PRODUCTION 55

in this country, as a result of which large areas have
been planted with a single species which would have
yielded much more profitable results planted as a mixed
wood.

It must not be thought that in criticising the
methods of forestry in this country that the blame
lies entirely at the door of the forester. The wonder is
that he has accomplished so mich against the number-
less disadvantages with which he has had to contend.
It is the duty of the ecologist to Supply those accurate
data in need of which the forester stands, and my plea
is for co-operation between the practical man who has
his hands full enough already looking after his nursery,
his plantations, and his timber, and the scientist whose
function is the provision of exact information and
advice.

In no respect is such accurate information more
scanty than with regard to association of species. The
data as to those which occur together naturally on the
different-soils cannot fail to aid in the choice of trees
for mixed planting, such as will not interfere with each
other’s development and yet contribute to the incre-
ment yield. And still more will such information
supply a warning as to what species should not be planted
together. Mixtures indicated by our present knowledge
are—

Calcareous soils: (ash and wych elm) and (beech
and yew).

Non-calcareous soils: (Q. sessiliflora and Spanish
chestnut), (Q. sess. and Fagus), (Q. robur and Populus
tremula).

The phases of succession which occur naturally on

56 EXPLOITATION OF PLANTS

different types of soil might well serve as a guide to-
wards the choice of nurse trees. Such would indicate
the almost universal employment of birch, preferably
Betula pubescens, on all non-calcareous soils, and the
use of ash on those which are calcareous. The freedom
with which these species colonise ground indicates
that they might be utilised for natural regenera-
tion, and later underplanted with shade-enduring
species.

One of the great decisions which a forester is often
~ealled upon to make is the choice of species for a newly
afforested area. In making this decision the soil con-
ditions are of the greatest importance, but unless he
has had the forethought to take soil samples for a year
previous he may be quite in the dark as to the extremes
of drought and moisture to which the area is subject.
Moreover, in addition he should know the chemical
constitution of the soil and its physical structure, each
involving a laborious determination. Yet the ecologist
could often tell at a glance, from the vegetation already
present, what were the prevailing conditions and what
trees would be most likely to succeed. In this con-
nection I would strongly urge that more attention should
be paid to the cryptogamic flora, which is often a very
delicate index of the soil conditions. For example,
the abundance of liverworts appears to bear a very
close relationship to the relative proportion of coarse
and fine particles, being very scanty both in individuals
and species where clay and silt predominate, and
becoming more numerous as the proportion of sand
increases.

Again, the proximity of the water table may often be

TIMBER PRODUCTION 57

gauged by the character of the mosses present. Thus:
the presence of Brachythecium rutabulum on a light sandy
loam indicates at once the unsuitability of the area for
beech, owing to the proximity of the permanent water
table.

Probably a careful study of the fungi and humicolous
lichens in this connection would yield results of equal
value, and we may perhaps look forward to the time
when cryptogams will provide indicators as valuable
to the forester and agriculturist as are vegetable dyes
to the analytical chemist.

Afforestation—We now turn to the very debatable
question of afforestation. There can, I think, be little
doubt that if afforestation be undertaken, it should be
by the State or by municipalities.

Firstly, the State is able to borrow money at a lower
rate of interest than the private individual ; secondly,
the private individual is seldom in a position to pro-
vide the necessary capital for afforesting a large area
such as is necessary for financial success; thirdly, the
return from timber is so long delayed that for some
years the capital yields no return, a matter of serious
consideration for the landowner.

Moreover, afforestation for the State is to be regarded
not merely as a national investment, but also as a national
insurance against timber famine. And since it is for
the benefit of the community in general, the community
as a whole, and not the individual, should bear the
burden.

In view of the current state of the money market
and the probability of the high value of money being
maintained for some time after the war, it is extremely

58 EXPLOITATION OF PLANTS

doubtful if the most paying species would yield a
return sufficiently large to attract the landowner,
especially having regard to the speculative character
of the investment.

But although one cannot go so far as some optimists
have done, and predict that State forests would yield a
high rate of interest, yet there is reason for believing
that it would prove at least as profitable as many of the
municipal ventures which are undertaken for the benefit
of local communities.

In this connection it must be borne in mind that
probably when this war is over we shall pass through
‘a period in which unemployment will be even more
acute than in the corresponding years succeeding the
Boer War.

Afforestation has been looked to as a palliative for
the unemployed problem, and though many objec-
tions can be raised on the grounds of the unskilled
character of such labour, it will probably prove the
best means of retaining and increasing our rural
population.

But by far the most weighty argument, to my mind,
for the establishment of State forests is their value in
bringing about the establishment of attendant industries.
We see this in the flourishing chair industry of High
Wycombe, which had its origin in relation to the regular
local supply of beechwood, but which now requires
large quantities of imported wood for its upkeep. In
the days after the war, when we shall have to strain
every sinew to re-establish our former wealth, will it
be too much to sacrifice a high rate of interest if we
can supply our home markets with converted timber

TIMBER PRODUCTION 59

or even perhaps wrest this trade from the hands of
foreign competitors ¢

Our supineness in respect to this aspect has lost us
industries in the past which the foreigner has been
quick to acquire. Where is the industry in crude
naphtha and oven charcoal which formerly flourished in
the North?’ Or again, what are we doing to protect
the industry in split chestnut fencing against unscrupu-
lous foreign competition? I venture to think that in
the future, we shall not deem it sufficient that the foreign
substitute be cheaper unless that lower price is an
expression of real ability in production, that more than
compensates for the transference of labour and wealth
to a foreign land.

The subject of afforestation naturally leads to the
question: What trees is it profitable to plant at the
present time ¢ Generally speaking, we may take it that
the cost of planting, of fencing, and of the young trees
themselves, ranges from about £5 to £8 per acre, accord-
ing to the method of planting which the soil and situa-
tion admit of. Now if we content ourselves with
requiring a return of 4 per cent. on the capital expendi-
ture, this will at the end of 120 years, the normal rota-
tion period for oak, amount at 4 per cent. compound
interest to about £890. In addition, there will be an
expenditure of some 2s. per acre a year over and above
the rental value of the sporting rights. This, together
with the cost of planting, will represent a debt at the end
of the 120 years of about £1160.

On a moderate soil a properly planted crop should
yield about £260, together with a sum of about £500
for the capitalised value of the thinnings at the end of

60 EXPLOITATION OF PLANTS

the 120 years. So that there would be a net loss at the
end of the period of about £400. If the trees planted
had been beech, the loss would be even higher, about
£620. On the same basis of computation, ash on a
70 years’ rotation would, however, yield a profit,
after paying compound interest at 4 per cent., of about
£170. This discounted into annual payments is
equivalent to a rental of 9s. 2d. per annum per acre for
the land.

On the chalk downs of the Chilterns we can find
extensive stretches covered with high forest consisting
of beech. In many parts, wherever clearings occur, we
almost invariably find ash appearing from self-sown
seed. These ash thickets are cut down and planted
with beech and sometimes larch. Were they retained
and properly maintained, they would show a handsome
profit in place of the present considerable loss.

It cannot be asserted that any other of our native
trees will show a profit if the debt be calculated at
4 per cent. interest. Larch, however, will yield a rental
value of about 5s. to Ios. per annum, and Douglas fir,
the most paying of all our trees, whether native or
introduced, will yield a rental value of as much as £2
per acre.

Even then, looked at as a purely financial investment,
afforestation on proper lines is not so unprofitable as
some have led us to believe. But if we compute the
return in terms not only of money but of employment,
decentralisation of population, establishment of rural
industries, and independence of sea-borne supplies,
then surely the undertaking is not merely justified,
but becomes a duty of national importance.

aes

TIMBER PRODUCTION 61

BIBLIOGRAPHY OF SELECTED LITERATURE

General—
Scuiicu, W. Manual of Forestry, 3rd ed. London, 1904.
Maw, P. T. The Practice of Forestry. London, 1912.
Report of the Royal Commission on Coast Erosion and Afforesta-
tion, vol. ii., pt. ii., Minutes of Evidence. 1g09.

Special—

Smitu, W. G., Moss, C. E. and Rankin, M. Geographical Distri-
bution of Vegetation in Yorkshire. Geographical Journal. 1903.

Moss, C. E. - Geographical Distribution of Vegetation in Somerset.
Geographical Society. London, 1907.

Vegetation of the Peak District. Cambridge, 1913.

WILsoN, M. Plant Distribution in the Woods of N.E. Kent.
Annals of Botany, vol. xxv. IQII.

Apamson, R. S. An Ecological Study of a Cambridgeshire Wood-
land. Jounal Linn. Soc., Bot., vol. xl. 1912

Sazispury, E. J. The Oak-Hornbeam Woods of Hertfordshire,
pts. iii. * Journal of Ecology, vol. iv. 1916.

CHAPTER V

TROPICAL EXPLOITATION, WITH SPECIAL REFERENCE
TO RUBBER

By J. C. WILLIS, M.A., Sc.D.
Late Director of Botanic Gardens, Ceylon, and Rio de Janeiro

To deal fully with tropical exploitation in an hour
is an obvious impossibility. I shall endeavour to indi-
cate the general principles which underlie its practice,
and illustrate my remarks especially by the case of
rubber, which has come into such prominence in recent
years, and with which I have had much to do, both in
tropical Asia and in South America.

Agriculture does not proceed by haphazard; we talk
about things as determined by chance, but that simply
means by causes which as yet we do not fully, if at all,
understand. But we are gradually coming to com-
prehend with reasonable clearness the chief causes which
are responsible for agricultural progress, and so it
becomes possible for those concerned with the govern-
ment of a country to act so as best to encourage it.

At first agricultural progress, if progress it can be
called, was dependent only upon one or two factors,
but as time went on it became dependent upon the

action of more and more. The incoming of the new
62

TROPICAL EXPLOITATION 63

factors does not throw out the action of the old, so
that the problem becomes more and more complex.
Any one factor, if it cannot act properly, may limit the
rate of progress until it is put right.

Agriculture in its earliest stages may be largely
summed up in the words, ‘‘ Grow what you want and
consume what you grow.” It was essentially what
would now be termed a peasant industry, but one must
remember that in early times there was but little differ-
entiation among the people. If for no other reason,
there could not be further progress because means of
transport were not yet developed, and so if a man grew
what he himself could not consume, he could not get
rid of it if his actual next-door neighbour did not happen
to want it. :

For this earliest agriculture, then, land available for
use—that is clear of forest or grass, drainable, and
supplied with sufficient water—and crops suitable to
growth upon that land, were the only absolute requisites.
The crops cultivated in those early days would of
course be those which experience of the produce of
the wild flora of the country had shown to be suitable.
Thus in a forest-covered country the great struggle of
the agriculturist, as it is to this day for the peasant in
districts where the population is thin, was to prevent
the crops being swallowed up by the continual in-
pressing of the forest.

As the country became cleared, paths began to be
opened up, and gradually it became possible to grow a
crop in one place and dispose of it in another, so that
differentiation in labour, whether within agriculture
itself or between agriculture and other occupations,

64 EXPLOITATION OF PLANTS

became possible. A class devoting itself to fishing,
for instance, could arise, arid the fishermen exchange
their fish for the products of agriculture which they
needed; this would react on the agriculturists, who
would now devote themselves to growing more of
certain crops, and would gradually find that they got
a better return per square yard than by growing every
kind of crop; this would gradually bring about a cer-
tain specialisation among themselves, one man growing
one thing, another another, and exchanging by means
of the markets that would gradually spring up. In this
way, provision of means of transportation acts as the
third differentiating factor in agriciltural progress.

A later stage was that the land was owned by large
owners, who had come into possession of it in various
ways. To possess a large area is obviously of no par-
ticular use if it cannot be cultivated, and this difficulty
was got over in different ways, perhaps most often by
a system of cultivation on shares, the land being leased
out to different cultivators, who pay to the landowner,
say, 50 per cent. of the resulting crop as his rent.
Sometimes forced labour was employed, but the share
system was more usual; hired labour only appeared
at a later time.

The next stages in agricultural progress, therefore,
after the provision of land and crops, are the provision
of means of transport and of capital—which enables
the purchase of land, tools, etc., to be carried on, and
allows of waiting for the return to come in after the
sale of the produce.

In Europe there is now comparatively little of the
old style of peasant cultivation, though it is tending to

TROPICAL EXPLOITATION 65

revive of late in modified forms. But in the tropics
progress was less rapid, and there had, previous to the
arrival of the white man, been but little progress beyond
the stage of ‘‘ grow what you want and consume what you
grow,” except in Peru, in India, and a few other spots.

To a large extent this continues to the present day,
and the bulk of the land employed in the tropics is in
the hands of peasant cultivators, or of large landowners,
who cultivate to a great extent upon the share systém.
But with the coming of the white man all the conditions
of agriculture in the tropics were altered, and a capitalist
agriculture was more or less violently superimposed
upon the other.

The incoming European brought capital (as money)
with him, and with the proper provision of this factor,
agricultural progress became possible far beyond the
point hitherto attained. At first he had little or nothing
to do with agriculture proper, but settled as a merchant
where he could procure the products of agriculture
and transport them easily to Europe for sale. This
determined the kind of locality in which he settled—
usually either at the mouths of the great rivers, which
afforded transport from the interior, like the Ganges,
or upon islands, like Ceylon or Java. These early
settlers collected and sold in Europe the products
gathered by the natives from the forests, like cinnamon
in Ceylon, or produce which certain districts produced
in excess of their own requirements, like rice in Bengal.

Before long the Europeans became themselves in-
terested in agriculture. Land was easy to obtain in
most countries, and native experience pointed out the

possible crops. Means of transport were usually bad,
F

66 EXPLOITATION OF PLANTS

but where there was a great river, or the country was
a small island, were generally sufficient. Capital was
available, and the only obstacle to progress was the
provision of the necessary labour (the fifth requisite
for progress) to grow the crops, and so for a long
-time the labour employed upon plantations owned by
Europeans was forced labour in the form of unadulter-
ated slavery.

With this, real exploitation of the tropics by
Europeans began. The first great agricultural enter-
prise was the sugar industry of the West Indies, where
all the necessary conditions were fulfilled in a very per-
fect manner. Transport was easy from these small
islands, and in the islands themselves presented but
small difficulties ; sugar was known to grow well, and
had a good market in Eurgpe ; land was easy to obtain ;
capital was provided from Europe; and the labour
problem was easily and simply solved by importing
African slaves. Rapidly there grew up a great and
prosperous industry. But with the abolition of slavery
all this was thrown out of gear, and the West Indies
sank into a state of great agricultural depression, out
of which they are now slowly rising.

The next great industry to rise was based upon hired
labour, and was the coffee industry of Ceylon. Land,
transport, and capital presented no difficulty, and labour
was obtained from the densely populated Presidency
of Madras, close by. The duty on coffee in England
had just been reduced, and its consumption was in-
creasing. By 1838 the success of the industry was
assured, and in that year 10,000 acres of crown land
were sold to planters, while in 1841, when the boom

TROPICAL EXPLOITATION 67

was at its height, no less than 78,000 were disposed of.
To quote Emerson Tennent, ‘‘ The Governor and the
Council, the Military, the Judges, the Clergy, and one-
half the Civil Servants penetrated the hills and became
purchasers of Crown lands . . . capitalists from Eng-
land arrived by every packet . . . so dazzling was the
prospect that expenditure was unlimited; and its
profusion was only equalled by the ignorance and
inexperience of those to whom it was entrusted. The
rush for land was only paralleled by the movement
towards the mines of California and Australia, but with
this painful difference, that the enthusiasts in Ceylon,
instead of thronging to disinter, were hurrying to bury
their gold.”

Soon after this there was the inevitable collapse,
but by 1855 the industry had recovered, and was con-
ducted on practical lines, forming the staple industry
of Ceylon until the eighties. Almost a million
hundredweights of coffee were exported in 1875. But
the writing was already upon the wall ; a fungus disease
was beginning to spread, was disregarded until too
late, and had as a result the complete collapse of the
industry, hastened and made more complete by the
competition of Java and Brazil.

Cinchona illustrates several other features in the
general study of tropical exploitation. The tree is a
native of the Andes, especially of Peru. The febri-
fugal properties of its astringent bark, due to the fact
that it contains the alkaloid quinine, were known to the
natives before the arrival of Europeans, and became
familiar to the Jesuit missionaries, one of whom cured
the Countess of Chinchon of a fever by its use. The

68 EXPLOITATION OF PLANTS

bark was for a long time obtained by felling the trees,
and as extermination appeared probable, Sir Clements
Markham was sent on an expedition to Peru to obtain
seed, with a view to the cultivation of the tree in the
British tropical colonies. He was successful in this,
and as the climate of India appeared unsuitable, it was
sent to Ceylon, where in the early eighties, when coffee
was failing, some planters were induced to give it a
trial, it having been shown to grow well in the Govern-
ment Botanic Gardens. Thanks to the then very high
price of quinine, the venture was extraordinarily suc-
cessful, with the result of a boom in cinchona cultiva-
tion. The effect was to lower the price of quinine
upon the market from 12s. an ounce, at which it once
stood, to 1s. 1d., which considerably reduced the profits
and reduced the industry to a state of comparative
collapse, which was hastened by the competition of
better barks from Java, where more scientific methods
were adopted, better species used, and care taken to
improve the yield by the selection of the best seed from
each generation.

Cinchona thus illustrates all the phases of European
exploitation of a tropical industry—the discovery of
the value of the product, its collection from the wild
plants by the cheapest methods, usually the most
destructive, its transfer to another country by means of
seed, its preliminary study by the aid of a botanic
garden, its first taking up by one or two planters, the
boom which followed their success, the resulting fall
in price, its more scientific treatment in another country,
and its collapse in the first owing to the competition.

Finally, let us turn to the tropical product whose

TROPICAL EXPLOITATION 69

exploitation has aroused the greatest interest in recent
times, viz. rubber. Rubber is obtained from many
different species, but the one that first came into notice,
the one that as a wild tree produces the greatest amount,
and the one that is by far the most commonly -culti-
vated, is the rubber tree of the Amazon valley, the tree
now usually known as the Parad rubber, Hevea brasi-
liensis. Other rubber trees of importance occur in
Africa, in Central America and Mexico, and elsewhere,
but though exploited commercially for all they are
worth, they are but little cultivated.

The Para rubber, growing in the valley of the largest
river upon earth, a river up which liners of 10,000 tons
can go for more than 1000 miles, and which has innu-
merable navigable tributaries, was fortunate in the
matter of transport. Capital was forthcoming, the
crop being profitable, and labour in the early days was
obtained by slavery. A merchant industry thus sprang
up, with its headquarters at Para.

This was all that was necessary for a very long period.
The Indians had known of the properties of rubber
for a long time, but it was little used in England or
elsewhere in the colder zones. The real advance in its
use came with tke discovery of vulcanisation, in which
by the combination of sulphur with the rubber, its
nature was changed, and it became much more durable,
and suited for the manufacture of many different sorts
of things. From that period onwards, the consumption
of rubber has increased without any serious break,
until at the present date it may be looked upon as one
of the indispensable products for modern civilisation,
like cotton.

70 EXPLOITATION OF PLANTS

About 1875 an expedition was despatched to the
Amazon by the Indian Government, under Mr. Wick-
ham, at the advice of Kew. At about the same time
the seeds of other rubber trees were also collected in
different parts of the world. A few score of plants were
raised at Kew, and sent to the East in charge of a special
gardener. The bulk were sent to Ceylon, and ‘the rest
to Singapore, although the cost was met by the Indian
Government, for experience of the climate in which
the tree was native showed that it could hardly be
matched in India. The seedling plants were estab-
lished in the botanic gardens in both countries, and
public interest in them ceased for about twenty years.

In the interim, rubber cultivation went off along what
has proved to be a side line. The seeds of the rubber
tree of North-east Brazil, Manihot ~Glaziovit, whose
produce is largely exported from the state of Ceara,
and which is known in trade as Ceara rubber, had been
brought to Ceylon about the same time, and proved to
grow like weeds. In the early eighties, when coffee
was failing, this tree, which seeded freely, was taken
up by a good many planters, and for some time there
was a small export of the rubber from Ceylon. What
was chiefly against the Ceard tree was the fact that
its yield was disappointingly small, while at the period
the price of rubber on the market was but low—two
conditions which, as we shall see, were almost exactly
reversed at the period of the incoming of the Pard
rubber. The cultivation, therefore, never spread to
any great extent, and gradually fell away to almost
nothing.

To return to the Parad rubber; about twelve years

TROPICAL EXPLOITATION va

after its establishment in the East, rough experiments
on yield began to be made in the botanic gardens there,
but had not very satisfactory results, Thus Dr. Trimen
in Ceylon showed that a yield of about 14 Ib. a tree a
year might be expected at ten years old, provided that
every tree yielded as well as did the one that he tapped,
which was the largest of the forty-five existing. To
wait ten years for a return meant a large outlay of
capital, and this amount of rubber, valued as it was.
considerably below as. 6d. a lb., did not offer any very
glowing prospects. It was a long time before any
planting estates were induced to plant the tree seriously,
and indeed it was also long before any large quantity
of seed was available.

However, in the nineties, especially as the result of
further experiments, which were carried out on larger
numbers of trees, and gave more encouraging results,
the tree began to be taken up to a greater extent, and at
the same time a rise in the price made the prospect of
profit more alluring. In the later nineties some of the
earlier trees in Ceylon were tapped, and produced
better results than was anticipated, and the planting of.
rubber was suddenly taken up with a rush. Seed, for
example, which was available in the botanic gardens,
had to be sold by auction, and at one period as much as
3d. was realised for each seed. In a year or two after-
wards the price went down, as large quantities began to
be available on the estates which had first taken up the
tree.

At the same time that seed began to be plentiful,
the results of the sale of the rubber first exported began
to be known. Soon it was clearly seen that the older

72 EXPLOITATION OF PLANTS

estimates had erred altogether upon the conservative
side. Wot only could more than 1} lb. be obtained
from a tree in a year, but the trees were found to be in
bearing at six years old; and the price obtained was
decidedly better than some years previously. The
result was to cause the pushing on of rubber planting
in Ceylon and Malaya to an extent that put even the
tea boom quite into the shade, and which is second only,
as far as tropical crops are concerned, to the coffee
industry of Brazil. We talk of the wonderful British
industry of rubber, but it is worth while to notice that
the value of the entire export, though rubber is worth
so much more per pound than coffee, is barely one-third
of that of the export of coffee from Southern Brazil.
From this time onward, the export of rubber from
Ceylon and Malaya went steadily and rapidly forward,
and we may quote the Ceylon figures to illustrate this—

1901 3 tons 6 cwt.

1904. 34 tons.
1907 354 tons.
I9QI2 4,506 tons.

1916 24,000 tons approximately.

The Brazilian export, it may be noted, is about 40,000
tons.

In 1907 there occurred the Ceylon boom, a precursor
of the great boom of three years later in London,- but
the Ceylon people knew better what they were doing,
and did not throw money away. Ceylon raised every
penny that was possible, and started many companies,
chiefly in the Malay States, where suitable land was
more readily available, and at the present time these

TROPICAL EXPLOITATION 73

companies are doing well. But the historic boom in
rubber cultivation was that which sprang up in London
in 1910, and during which many fortunes were made
or lost.

The plantation rubber of the East is now the chief
rubber upon the market, for the export of the wild
Brazilian rubber has stood practically steady at about
40,000 tons, and that of the African and other wild
rubbers is much less. What has perhaps most of all
surprised the planters of rubber is that they have been
unable to kill off the Brazilian trade. To close our con-
sideration of tropical exploitation, it may be of interest
to go into this question.

It would be very unscientific to prophesy that the
cultivated rubber will never kill out the wild, but the
time is not yet. One great difficulty in the way is the
fact that, though it is often denied, the Brazilian up-
river hard cure, as the finest rubber is called, is superior
in quality to any of the plantation rubber. No one who
has seen them side by side in quantity could have much
doubt on the subject.

The cultivated rubber is all marketed in a form that
contains practically no water at all, whilst the wild rubber
has about 15 per cent. This fact is usually lost sight
of in comparing the market prices. At to-day’s rates,
for example, 85 Ib. of dry Brazilian rubber is worth
3355. against 278s. for the same quantity of plantation.
This fact struck Mr. Bamber and myself at the Ceylon
Exhibition, and we made a rubber which contained
water, and was of better quality; but by sending to
market rubbers with different percentages of water,
people soon spoiled any chance of success which this

74 EXPLOITATION OF PLANTS

method might have had. And this difference is not the
only one, there are others. For certain fine qualities
of goods the fine Brazilian rubber must continue to be
used, if the best results are to be obtained, for example
for inner tubes, for surgical instruments, and the like ;
but, as the plantation rubber now controls the market
by being present in much greater quantity, it forms an
industry per se.

But to complete our study of tropical exploitation,
it may be of interest to deal briefly with the steps which
-are being taken in Brazil to meet the competition of
the plantation rubber, which is admittedly very formid-
able. The cost of placing the Brazilian rubber on the
market is ahead of that of placing plantation there,
though the increased price almost equalises it, and the
problem is how to reduce it. Export duties, at present
almost 20 per cent. ad valorem, are being reduced, and
would be more rapidly reduced were it easy to get the
enormous cultivable areas of the Amazon valley, the
richest tropical land on earth, taken up for other kinds
of agriculture. Rubber is the only taxable value in
the Amazon states, and therefore provides their revenue.
Here, one may perceive, is one of the problems of the
kind that confront the man who is occupied with tropical
exploitation, and which one is-apt to think, when one
is young, and fresh from the study of science at school
and university, are purely scientific problems, whereas
in reality they are much more complex, and are rather
problems of finance and political economy. Given
the Amazon valley, one knows that land is available ;
one knows that cacao, rice, rubber, and almost innumer-
able crops will grow well there. Why, then, cannot

TROPICAL EXPLOITATION 5

agriculture ‘be made to succeed ¢ To begin with, most
of the land is covered with high forest, and the small
cultivator will spend most of his time and work in
fighting the continual inroads of the forest upon his
crops. The only chance for any kind of rapid opening
up is that people with sufficient capital to open up large
areas should commence there. But if capital come in,
then transport is also necessary, to get the crops away
for sale in large markets. Now in the Amazon valley
there is an absolutely unrivalled water transport avail-
able, and this is the cheapest form of all, generally
speaking. But even here great difficulties spring up.
At many places there are great rapids in the big tribu-
taries running from the south, and to escape these rail-
roads are needed. A beginning of such lines has been
made with the Madeira-Mamoré railroad, but many
more are needed, and in the present state of the country
they have nothing to depend upon but the carriage of
rubber. A second great difficulty is the fact that
transport is easy enough down stream, but unfortunately
the boats have to come back against the current, and so
unless they can get freight back, they must charge high
rates for going down. ‘This reacts in a way which we
shall understand better in a moment. For the present
it will suffice to say that one of the chief factors against
the opening up of the Amazon valley is the compara-
tively high cost of transport.

The cultivation of small areas by small cultivators is
‘being pushed on by the Brazilian Government as much as*
possible, for one of the chief causes of the high cost of
getting rubber is the fact that practically all food sup-
plies have to be carried up stream—none can be obtained

76 EXPLOITATION OF PLANTS

locally. But against progress in this direction must
be set the fact that if the river steamers do not carry food,
they have almost nothing to carry up stream, and so
must charge higher freights for bringing the rubber
down, so that the one thing works against the other.
But transport is not the only factor whose proper
working is not as yet ensured in the valley of the Amazon.
For the cultivation of large areas of land labour is neces-
sary. Now the population of Brazil is as yet small,
and the country is larger than the whole continent of
Australia, while the coastal lands are by far the most
healthy in the tropics. It is from these healthy north-
eastern states that the labour of the Amazon valley has
hitherto come, and especially in the years when the
cotton crop, upon which they chiefly depend, has been
bad. But now the Brazilian Government is taking the
wise step of pushing cotton cultivation in the north-
east, under charge of one of the first American special-
ists, and as Brazil is the native land of most of the
cottons, and has about a million square miles of mag-
nificent cotton land, the result will inevitably be to
diminish the supply of labour for the Amazon. The
obvious remedy, many capitalists will say, is to import
Chinese or Japanese, who can stand the climate. No
doubt this would in a way solve the problem, as slavery
would solve it, but the Brazilian stands out for a
Brazilian Brazil, and does not desire to be flooded
with Orientals any more than does Australia, For the
present, therefore, labour supply is even a greater diffi-
culty in the path of those who wish to open up the valley
of the Amazon than is transport. After all, the latter
can be largely avoided by opening up at first only the

TROPICAL EXPLOITATION 77

land near to the mouth of the river, an enormous area.
But the labour problem is the great difficulty.

This digression upon the economic conditions of the
Amazon valley-has been introduced to show the kind
of problem which is involved in dealing with tropical
exploitation. But the same kind of problem turns up
when we come to deal with the opening up of any
of the British tropical colonies. Take, for example,
Guiana, contiguous to Brazil, and just as rich by nature ;
is it to be slowly populated by British Indian coolies
growing rice, as is at present happening, or is it to be
exploited more rapidly and completely in some other
way¢ The question is political, as is also the question
as to whether we should use the African colonies for
growing large quantities of cotton, though Brazil is
better suited to that crop, and has a much larger area
available. But if we did not possess a large area yield-
ing cotton, we might as an empire be at any time at the
mercy of outsiders, and so it seems advisable to sacrifice
some agricultural efficiency to political considerations.
All these things, one may perceive, are at present
much more questions of finance, labour, or politics,
than of scientific agriculture properly so-called.

To return to rubber and the measures being taken in
Brazil to meet the competition of tropical Asia. One
of the most obvious would seem to be to introduce the
use of the tapping knife employed in the East, instead
of the machadinho (little hatchet) at present employed,
and which gradually covers the tree with awkward scars.
This seemed so obvious that it was tried on one or two
places with bad results. In the damp air of the Amazon
valley, the cuts became perfect hotbeds of fungus

78 EXPLOITATION OF PLANTS

disease, and many trees were lost. Here, you might
almost say, was the first application of science to the
Brazilian rubber industry, and as has often happened
in the East, the results were disastrous. We are slowly
learning that while the native methods of any given
place may be very bad and very inefficient, they are in
general the best for the local conditions as they existed
at the time when these methods were employed ; they
are open to improvement, but the improvement must
go hand in hand with that of the other conditions, and
must be very gradual and cautious. Before the tapping
knife was employed in Brazil, there should have been a
series of experiments carried out to determine the best
way in which to use, and if needful to modify, the new
tool. As it is, the tappers in the Para district have
acquired a prejudice against the knife, whereas there is
little doubt that by its careful and judicious use a large
number of trees could be tapped which are at present
left idle as being too small.

Another problem is the sernamby, or scrap rubber,
produced in great quantity and of but poor quality ;.
the collector most often gets the scrap as his pay, and
so does not make any more fine hard than he must..

Yet another great difficulty is the supply of neces-
saries to the collectors ; little is cultivated up the valley,
and food and necessaries are supplied by the merchants
in Para and Manaos, in exchange for the rubber. We
have already been into this question from the transport
point of view ; it is merely brought up here to show the
way in which all parts of the problem hang together.

The whole problem, so far as Brazil was concerned,
was much complicated by the high. prices obtained for

TROPICAL EXPLOITATION 79

rubber a few years ago, which caused the great boom
in planting rubber in Asia, and made the merchants of
Para and Manaos think that the millennium had arrived.
Extravagant ways of dealing grew up, and now that the
pinch has come it is, as usual, found that it is a good
deal easier to increase expenditure than to reduce it.
There is no reason to doubt, however, that reduction
is steadily going on.

We have now surveyed in a very brief and superficial
way some of the enormous field of tropical exploitation,
the object being not so much to give actual facts as to
illustrate the underlying principles that are operative
in tropical, as in other, agricultural progress. The
same principles rule everywhere, and it will be well,
before going any further, to recapitulate them. In the
first place, we must have land available—that is to say,
it must not be merely land, it must be clear of forest
or other growth, it must be drained enough for the
purpose, and if needful it must be irrigable, or have
water available. We must also have crops which will
grow upon that land, and whose produce can be used
by the cultivator. The next stage begins with the pro-
vision of means of transport, by which the cultivator,
instead of using all that he grows, may sell some of it
elsewhere (or barter it), and obtain other things with
the proceeds. This in itself does not mean any great
advance till the next factor—capital—comes into opera-
tion, and enables a man to have a larger area, to culti-
vate with hired labour, and to wait for his return till the
crop can be sent to a distant market for sale. Capital
without labour can of itself lead to nothing. We thus
have, as the conditions for successful exploitation, as

80 EXPLOITATION OF PLANTS

so far carried on in the tropics, land, crops, transport,
capital and labour, and only when all these factors come
into proper operation is there any real exploitation
going on. When no exploitation occurs, it is the duty
of the rulers to study the question, and find out which
factors are not in proper operation, and to bring them
into bearing, as I have endeavoured to indicate in
sketching the conditions of the problem in the great
valley of the Amazon.

But now, in conclusion, this is a scientific course of
lectures, indicating in general the applications of botany
to agriculture, and one will naturally ask, after hearing
that the conditions which govern tropical exploitation
or its absence are mainly political or economic, where
does science, and especially botany, come in? Well,
except in one or two directions, it does not come in
until all these preliminary conditions for successful
agriculture have been fulfilled.

Botany has’ obviously nothing to do with transport,
finance, labour, or land, and it is only in the section
crops that it enters into the problem, but it enters there
.in a very important way. The earliest agriculture in
the tropics, as has been mentioned, was concerned
naturally with those plants of the indigenous flora which
experience had shown to be useful, but very early in
the history of the opening up of the tropics by the white
man it was realised that there might be crops which
would be more profitable to cultivate than these. The
Portuguese in the sixteenth century already set about
introducing into the various parts of their empire the
crops of other portions, and at the present time most
of the crops that grow in Ceylon in the gardens and

TROPICAL EXPLOITATION 81

fields of the natives, other than rice and cinnamon, are
things that were introduced by the Portuguese. With
the coming of the Dutch the introduction of foreign
plants was placed upon a more systematic footing, and
botanic gardens were opened, whose principal business
it was to attend to this introduction, and having intro-
duced the plants to grow them in the gardens until it
was reasonably certain that they would succeed in the
country. By the time of the coming of the English to
preponderance in the tropics, most of this work had
been done, and the botanic gardens were decreasing
in usefulness. For a long period, however, all that
Governments did to encourage agriculture was to keep
up these gardens, to attend to the question of crops,
and usually to keep up a department to attend to land,
and a third for transport. Only in recent years has the
whole problem involved begun to be understood, and
proper departments of agriculture formed to attend to
as much of it as possible.

But until quite lately there was no need for any
scientific help other than in the provision of crops,
with an occasional bit of assistance in dealing with some
troublesome disease. Now, however, that nearly all
crops in the tropics have been taken up with all the
resources of land, crops, transport, labour and capital,
the time has come when scientific assistance can be and
must be provided in another form. It forms the sixth
factor necessary for agricultural progress, and a great
need of the day is a supply of properly trained young
men who can work in the new departments of agricul-
ture at the many problems involved. With the taking

up of practically all crops by capitalist agriculture, com-
G

82. EXPLOITATION OF PLANTS

petition begins to be involved to a very serious degree,
and each country wants to equip its agriculturists to the
best advantage. New varieties, suited to the local
conditions, can be produced by breeders trained in the
principles of Mendelism. Mycologists and entomo-
logists can aid in the suppression or extermination of
the many diseases to which agriculturists owe such great
losses. Bacteriologists can investigate -soil problems,
chemists the same, and both can work at the numerous
problems which turn up in finding out the best methods
of preparing such crops as rubber or tea. Engineers can
work at the improvement of machinery, whether the
larger machinery of the capitalist or the small tools of
the small cultivator. All these improvements apply
chiefly to the capitalist agriculturist, but the small man
can also be helped, especially by the provision and
encouragement of co-operative credit societies, which
may help him to get free of the incubus of debt, and
ultimately bring him into what we term the capitalist
class of agriculturist. The day of science as applied
to tropical agriculture is dawning, and we may hope
to see great results. The tropics provide an immense
area of rich and unused land, and their proper exploita-
tion will not only provide for an enormous native popula-
tion, but will supply the wants of the colder zones in a
way that has never hitherto been dreamed of,

CHAPTER VI

THE COTTON PLANT, ITS DEPENDENT INDUSTRIES, AND
NATURAL SCIENCE

By W. LAWRENCE BALLS, Sc.D. (Cantab.)

Fine Cotton Spinners and Doublers’ Association.
Formerly Botanist to the Khedival Agricultural Society of Egypt, etc.

THOSE subjects of the State who are scientists by
training, and still more those younger scientists who
are seeking a useful career, can only be very thankful
that a national conviction with regard to scientific
method and result has at last been awakened. But
since this conviction is hasty, largely Press-made, and
is not based on real acquaintance with experimental
methods, it will not easily be transformed into working
practice. :

Such transformation will be hardest in the domain of
pure science—which, fortunately, is less expensive than
industrial research—because the economic application
of its incidental discoveries must of necessity be uncon-
ventional. This, too, is the happy hunting-ground of
the charlatan. ~

The transformation is easiest on the fringe of working
practice, where minor difficulties, which arise day by
day, are demonstrably most easily solved by trained
men. Here the immediate practical utility of the
scientist is as obvious as that of a telephone or of a

83

84 EXPLOITATION OF PLANTS

typist, and the returns are quick. On the other hand,
the exercise of the Craft of Research is so restricted,
and its potentialities are so cramped, that the word
Investigation is now being employed to indicate the
purely utilitarian and detective function of such work,
as distinct from the limitless scope of Research proper.

Between these two there is an enormous field for
work, which has scarcely been exploited as yet, where
any results achieved are inevitably of some value to
the State, and where there is also a very large chance
for the open mind to discover lines of inquiry which may
lead up to scientific conclusions of the first order. This
field corresponds to the strict definition (now much
abused) of Applied Science, and its scope may be
defined as the conduct of strictly scientific research,
with all its professional criteria of precision and ex-
haustiveness, but limited in its central subject to material
of economic importance.

This field of work is even more fascinating to some
minds than pure science, being in the closest relation
with the intellectual problems of science, on the one
hand, and with the State-service aspects of industry on
the other. Research in this field has a direct educational
value for the student, in that it brings him to realise
the intimate dependence of all research upon the un-
limited labours of the laboratory, and it throws up in
vivid relief the enormous lacune which exist in the
web of our present- knowledge. An example may
illustrate these points—

The writer studied the effect of sowing Egyptian
cotton in successive weeks for nine weeks around the
usual sowing-date, using every known experimental

THE COTTON PLANT 85.

precaution, such as chequerboard plots, differential
irrigation, plant-development records, and statistical
treatment. The result had three main aspects: first,
the State aspect, by showing that the conventional
practice of the Egyptian native in not planting very early
was the correct practice under the existing climatic and
agricultural conditions ; secondly, the utilitarian aspect,
by systematising the routine of propagating valuable
pure-strain seed so as to involve the minimum risk of
damage or loss, either to the seed put into the ground,
or of the expected harvest. Lastly, and most im-
portant, it showed up a gap in our knowledge of the
relation between temperature and the permeability
of protoplasm, because the observed facts were only
explicable on an hypothesis that the permeability of
root-hairs as well as the growth of the root was a loga-
rithmic function of the soil temperature; the only
existing scientific data (Von Rysselbergh) showed no
such simple relation. Subsequently and independ-
ently this relation was actually found (Delf) in purely
laboratory work directed solely to the study of proto-
plasmic permeability, using for convenience the hollow
flower-stalks of dandelion and leaves of onion; the
gap in our knowledge was thus filled up, and the new
knowledge is of importance, not only to cotton and to
all agriculture, but to all our knowledge of Life ; as
a current example, it may be applicable to the technique
of asepsis during irrigation treatment of wounds.

The field of science in relation to the cotton indus-
tries has two main divisions, the study of the Plant as
a producer of cotton hairs, and the study of the cotton

86 EXPLOITATION OF PLANTS

hairs as raw material for industrial purposes ; but it
must be understood that these divisions are convenient
mental abstractions, not water-tight compartments,
and that they break down and intercommunicate in
sound research practice; obviously, cotton should be
grown to meet the needs of the consumer, and the
consumer is limited by the capabilities of the plant.

For all practical purposes we may regard the second
division as an untouched field for serious modern
research, while the first has only been pioneered suffi-
ciently to indicate its possibilities. The various sub-
jects available for study, and their general interrelation,
are indicated in the following table, which, in its present
form, needs a little amplification.

.The task before the Grower is to grow the right thing ;
firstly, in sufficient quantity to pay him adequately for
the land and labour employed; thus his concern is
primarily with Yield. Since the financial return is not
dependent on yield alone, but on the product of yield
by price, he is also concerned with Quality ; whether
such quality be due to inherited properties of the
variety grown, or to the effects of cultivation, or to both
causes. The conduct of the Grower’s work in regard
to the yield obtained from a given variety is a form of
Applied Plant Physiology ; so also'in the matter of the
quality of cotton obtained from the same variety; in
the choice of the variety grown he is implicated at
more or less distance in researches on the isolation of
pure strains, and the working of Mendel’s Law in
hybrids.

The job before the Spinner—allowing him to typify
the consumers of cotton—is to arrange the tangled

THE COTTON PLANT 87

cotton hairs gently in the most regular way possible,
so as to form the strongest and longest threads from a
given weight of raw material under limitations of out-
put and cost. His concern is mainly with Quality. The
actual growing of the crop does not appear at first sight
to affect him, but closer consideration is now showing
this to have been short-sight ; except by accident he
cannot obtain the quality of cotton he wants, unless he
‘knows what he wants, and why he wants it. The
interests of the Grower and the Spinner are therefore
intimately linked together; they are not merely an-
tagonistic ; the former, chiefly interested in yield, loses
something if he grows poor stuff which the spinner does
not want; the latter, chiefly concerned with quality,
has to pay for it unduly if the grower’s yield is low.

GROWER anp SPINNER

(Yield) (Quality)
Plant Physiology Gametic Composition of Crop
Fluctuation

Crop Physiology Mendelism

Crop Records Agriculture Pure Strains
Crop Reports Variety Testing
Crop Forecasts Seed Supply
Merchanting Spinning Technique, etc.

(Economics, Transport, etc.) (Physics, Colloids, Chemistry,

Engineering, etc.).

The total cotton crop of the world before the war
amounted to a weight of some 12,000,000,000 Ib. per
annum of cotton lint. The crop is usually spoken of in
terms of “ bales,”” and since these bales vary somewhat

88 EXPLOITATION OF PLANTS

in weight according to their country of origin, the
nominal unit bale is one of 500 lb. It will be easiest for
the general reader to deal with pounds, or rather with
thousands of millions of pounds; the distribution of
the world’s production and consumption of cotton then
appears as follows, grouping the countries according
to their political relations.

THE WORLD’S COTTON CROPS. After J. A. Topp.
(Expressed in thousands of millions of pounds weight.)

Production, 1912-13. Consumption, 1913-14.
USA 3 a 2 # © « 730 USA: «. 4 ce = a B66
India . . . . . . 260 Great Britain . . . 2:10
Egypt . . . . . . °75 ~~ India ot Broce of CHAO!
Russia . . . . . . 50 Russia . 2. . . . 6125
Other Allies . . . . ‘10 Japan . .. . . ‘80
Neutrals . . . . . 50 France . 1. . 2.) 50
Turkey. a4) <a ae, “S900 Ataly sok a A gO
Ghia” = -% gw &%- ~ ¢ Belgium. 2...) . ‘10

Portugal. 2. 2...) 05
Canada . . . . «05
Neutrals . oh ara “Seas
Germany . . . . :85
Austria... . . 40
Ching . 1... ¢
Total Crop (Excluding Total Consumption (Ex-
China) . . . . 11°85 cluding China) . . 10°85

It will be clear from this table that the U.S.A. domin-
ates the world’s supply of cotton, and is, moreover,
a great cotton manufacturing country. The remainder
of the supply is largely British, including the Egyptian
crop, and a small but valuable crop from the West Indies,
which will now be almost the sole source for very long
fine cotton (the “ boll-weevil” having made its way
into the Sea Island districts of the U.S.A.) excepting
the Islands themselves. It should be understood that

, THE COTTON PLANT 89

different species of cotton are grown, which vary greatly
in value and in capabilities ; these variations depend
partly on the length of the hair, which ranges from a
quarter of an inch to somewhat more than two inches.
The bulk of the Indian crop is about half-inch, that
of the U.S.A. one inch, that of Egypt under one and a
half inches, and that of the West Indies over one and a
half inches. Concurrently with these and other differ-
ences there are differences in the fineness of the material,
yarn, and fabric made from the cotton, and the finer the
yarn the more time and work is spent on making it.
These peculiarities show up in statistics of consumption
per spinning spindle, which range from nearly 350 lb. of
cotton per annum per spindle in Japan, where the mills
run all night, or 170 lb. in India, down to 383 Ib. in
England, and 35 in Switzerland. England being the
original home of the cotton-spinning machines, it is
-only natural :that we should have tended to monopolise
the finer spinning, though our initial lead in even this
matter, and still more in ordinary spinning, is steadily
decreasing.

It may be asked why the great sub-tropical areas of
the British Empire do not provide enough cotton to
restore some sort of balance to the world’s supply,
instead of leaving it dependent on the chance of good
or bad weather in the United States; or‘again, why
India should not grow better cotton’ There are many
reasons, some valid, some invalid, but the primary one
and the central fact of the situation is simply, that we
do not know enough about cotton. The real scientific
exploitation of the cotton plant has not yet begun, be-
cause exploitation cannot begin without exact knowledge

go EXPLOITATION OF PLANTS

of the plant exploited. Further, such study and ex-
ploitation must be effected in close inter-relation with
the consumer, if the results are to have practical
significance. There are scientific workers in various
countries studying the cotton plant, and the British ones
have shown the way in more than one case to their
American colleagues, who had a very long start, but
from the nature of the case their nominal official work
consists rather of Investigation as we have defined it, than
of deep-digging Research. There could be no more
convincing example of the vagueness of our present
knowledge than the fact—almost incredible—that only
during the present decade have the U.S.A. growers
discovered how to increase their yield per acre by 30
per cent. at no cost; the method is simply to leave
twice to three times as many seedlings standing on the
area as had previously been the custom. Incidentally
it may be added that the Egyptian fellah many years ago
discovered the equilibrium-point in this system of
diminishing returns, on his own account, by the accumu-
lated experimental evidence involved in growing and
selling his crop, and he has steadily resisted the
well-intentioned efforts of would-be reformers with
smatterings of biology, who wished him to adopt wider
spacings of his plants. The present writer studied
the principles involved, and America has now copied
the practice.

If another example were needed, it might be found
in Mr. Leake’s assertion that the whole of the work on
the introduction of exotic cottons into India during more
than a century needs to be repeated ab initio. The
cotton flower was always assumed to be self-fertilised,

THE COTTON PLANT gI

or only very occasionally cross-fertilised, until the
writer showed in 1905 that from 5 to 10 per cent.
of the ovules were habitually crossed under actual
field conditions. Then it was easy to see why new
cottons deteriorated or acclimatised themselves, why no
new variety ever reached the market in a truly pure
state, and why uniform cotton was unobtainable. Leake
demonstrated independently that the same conclusions
applied to Indian cottons, and drew the logical, but
daring, deduction which we have just quoted.

Without the assistance of photographs, sketches and
graphs, it is hardly worth while to attempt any account
of the life-story of a cotton plant, and the reader who is
desirous of further information may perhaps be referred
to the writer’s Development and Properties of Raw
Cotton, but it might be of use to draw attention to a
method of study which the writer has worked out to
some degree of refinement for the study of Egyptian
cotton, and by means of which some permanent results
have been obtained, together with a fairly adequate
comprehension of the manner in which any result
was reached. This method is simply the obtaining of
a continuous statistical record of the life-history, which
can be plotted in graphic Curves of Plant-development,
studying the crop—whether of a plot or of a country—
as an Average Plant. Cardinal points are chosen for
observation, the chief of these in the case of cotton
being the number of flowers opening per plant per day,
together with the height of the main stem and the
ripening of the capsules or “ bolls.” The records can
be carried to an incredible degree of precision by suit-

92 EXPLOITATION OF PLANTS

able scatter of the observed groups of plants, each group
numbering about 200 plants ; equally, they can con-
stitute a very serious waste of time and energy if the
observed groups are not scattered so as to be compar-
able, as a recent publication has shown. They can be
utilised in a number of ways; in the first place, they
abolish that bug-bear of agricultural experiment, the
Probable Error of a Single Plot, since by showing exactly
how the final yield was built up, they show how plot-to-
plot differences arose, and so convert the probable error
into.a recognisable error due to definite physiological
causes. They serve as seasonal or site-records of crop
behaviour, and, if obtained at a sufficient number of
observing stations, they could depict the crop of a whole
country in a form which appeals to the eye, and is further
of exactly definable precision. Moreover, such records,
as they grow day by day along the squared paper on
the laboratory wall, very soon begin to foretell their
own form; the rates of stem-growth indicate what will
be the flowering-rates three weeks later, and these again
determine the rates of fruiting two months afterwards, so
that a system of cold-blooded Forecasts for any country
can be developed at small cost of organisation to replace
the present subjective expressions of more or less dis-
interested expert opinion. They not only show the
effect of weather conditions on the crop, but even in
our present state of knowledge they can occasionally
be used as records of the environment. Lastly, variety-
testing can be conducted with absurdly small quantities
of seed, thus enabling real agricultural trials of new
strains or varieties to be made at a very early stage of
the breeding work ; for this purpose the observed groups

THE COTTON PLANT 93

are planted here and there through an ordinary field of
a variety which is roughly similar in size and habit of
growth; they obtain no special treatment whatever,
but are carefully observed day by day.

Having mentioned the subject of plant-breeding,
we should make a serious omission from this article if
we neglected to mention the possibilities of Mendelism.
The work which has already been carried out in this
direction on cotton, under the limitations already men-
tioned, shows promise of useful results in the future,
but any serious investigation of heredity, as such, in the
cotton plant, is beyond the powers of ordinary agricul-
tural experiment stations, for the following technical
reasons, The plants are large, and even a small
“‘ family ’’ occupies a great deal of ground; they are
subject to sufficient natural crossing to obliterate entirely
the demonstration of the more subtle Mendelian ratios
unless the flowers are artificially protected at consider-
able expense from such contamination; the work of
the writer in particular has shown that such ratios,
indicating complex inheritance, are far from uncom-
mon; further, many or most of the characters which
have economic importance are not matters of colour
or form, but of dimension, and before these can be
studied adequately in their inheritance, the student
must have intimate knowledge of the possible fluctua-
tion which such dimensions may undergo as the result
of mere environmental changes. Lastly, the practical
application of such results as have been obtained has
been hindered because the grower has been working
in the dark, on account of the absence of detailed know-
ledge on the consumers’ side of the trade; there has

94 EXPLOITATION OF PLANTS

been no common language in which the spinner could
explain to the grower the exact kind of cotton he required
to meet his need.

One practical conclusion seems to be definitely estab-
lished, which is this: that a gametically pure cotton
spins stronger yarn than an ordinary impure com-
mercial variety of similar type, alii xquando, even
though the latter is of much more pleasing appear-
ance. This last remark carries with it the implication
that the highly skilled judgment of the cotton-grader
should not be trusted entirely in approving or con-
demning new kinds of cotton, as regards. their spinning
qualities; means should be developed whereby the
testing of such cotton may be conducted by actual
spinning-tests, for, after all, cotton is grown to be spun,
and to judge it by its mere appearance is an unscientific
conclusion to scientific labours.

Our space will not permit of any attempt to describe
the various processes of manufacture through which
raw cotton may pass; they may be summarised as
Spinning, with doubling; Fabric construction, by
weaving, knitting or lace-making ; Bleaching ; Dyeing ;
Calico printing; Finishing.

The end product may be any of the well-known cotton
fabrics—sheetings, nainsooks, cambric, muslin, sewing-
cotton, lace, or hosiery; it may be a blanket, motor-
tyre fabric, sutde-finish gloves, or a useful and satis-
factory imitation of almost anything commonly made
from silk, wool, or flax. With such a range of possi-
bilities for industrial research it is useless to deal here,
and we will confine ourselves to a few figures indicating

THE COTTON PLANT 95

the delicacy of the initial process on which all this pro-
duction depends, namely, spinning, and remembering
that there are nearly 60,000,000 spindles spinning cotton
in Great Britain alone, that the produce of a single plant
of Egyptian cotton is worth less than a farthing, and
that the weight of a cotton hair is of the order of 0,004
milligrams,

We have mentioned that this country specialises on
fine spinning, averaging about 4os counts, at the rate
of 383 lb. per spindle per annum. In effecting this
production the spindle in question would put about
1100 million twists into the length of yarn produced,
and this length would exceed 7oo miles. Ordinary
40s sewing cotton consists of six such strands of yarn.
But spinning js carried on commercially to counts as
fine as 300s and over, for special purposes ; one mile of
such yarn weighs three grams, and has received about
four million twists.

These mechanical processes whereby the tangled epi-
dermal hairs of the cotton-seed are finally arranged in
regular sequence, all straight and parallel, with as few
as twenty hairs in the cross section, date back in their
conception to more thanacentury ago. Although many
improvements and refinements have been introduced
into the machinery, and although the speed of produc-
tion has been enormously increased, there have been
no further inventions of primary importance for over
sixty years.

The basis-mechanism of the whole machinery is the
“ drafting-roller ’’ patented by Lewis Paul and John
Wyatt in 1738. The cotton is fed into the nip of one
pair of rollers, and shortly after emerging from this nip

96 EXPLOITATION OF PLANTS

it is gripped by another pair which are running at a
higher surface speed. The hairs between the two nips
are thus dragged apart, rendered straighter and more
nearly parallel, while the strand of cotton delivered
from the second pair is necessarily thinner than before.
In combination with preliminary cleaning and disen-
tangling processes, with the doubling together of two
or more strands to obliterate irregularities, and with the
actual twisting, this drafting mechanism performs the
process of ordinary cotton spinning.

Considering the greater knowledge and control which
we now possess as regards physical processes, in com-
parison with our grandfathers, and considering also
that a strand of cotton yarn is a very long way from being
the uniform ideal product, we may reasonably consider

that there are possibilities for research in this direction
also.

Lest the contrast which we have attempted to create,
as between the world-wide interests of the crop in
bulk, and its final resolution almost into single hairs to
construct threads of yarn therefrom, should not have
appealed sufficiently to the reader, we may point out
that even the home industry in cotton is so great as to
head the list of exports from the United Kingdom, and
to employ capital which is estimated to be about
£250,000,000, without reckoning the imperial interests
in cotton-growing and spinning. Since the war aroused
interest in the possibilities of scientific research methods,
two attempts have been made to initiate systematic
organisations for fundamental research on a scale worthy
of this industry, bearing in mind that the word Industry

THE COTTON PLANT 97

does not merely connote the spinning and manufacture,
but the growing of cotton as well.

The first of these attempts was directed to the forma-
tion of a department in the University of Manchester,
at the time of the British Association’s visit in 1915,
but it was a little too far in advance of public opinion.
Subsequently the Department of Scientific and Indus-
trial Research took the initiative, and a Provisional
Cotton Research Committee has undertaken to formu-
late a suitable project for the purpose.

In any attempt to evaluate the potential importance
of such research to the Empire, it should be remembered
that the inventive genius of Wyatt, Paul, Hargreaves,
Crompton, and Arkwright made England the original
home of mechanical cotton-spinning. That some of
the adventitious results of their genius are not entirely
commendable is beside the point ; the brains of these
men contributed largely to create our modern prosperity.
Subsequently we lost much of this initial supremacy as
other countries learned how to spin for themselves, but
we naturally retained a superiority, in the form of
finer spinning than our pupils and competitors. Never-
theless, though Lancashire possesses certain natural
advantages, some of these are less important than they
were in the past, and after a certain time it is inevitable
that the product of our rivals will approach or even
surpass our own if we do not exert ourselves to regain
our initial lead, by scientific study of our industry from
the cotton-field to the factory, and by a renewed deep-
seated inventiveness.

It will be seen from the preceding account that there
is no lack of material for study, and we may hope that

H

98 EXPLOITATION OF PLANTS

a few years of good mental team-work will begin to re-
establish the threatened security of this amazing industry
upon a sure foundation of knowledge.

GENERAL REFERENCES
Economics—
“The World’s Cotton Crops,’ J. A. Todd. London, 1915.
“History of the Cotton Manufacture,’ E. Baines. London, 1834.
“The Cotton Manufacture and Trade,” S. J. Chapman. Man-
chester, 1907.
Reports of the International Federation of Master Cotton Spinners,
Secretary, Arno S. Pearse. Manchester.

Mechanism of Cotton Spinning—
“Cotton Spinning,” W. Scott Taggart. 3 vols. London, 1906,
1917.
Systematic Botany—

“ The Wild and Cultivated Cottons of the World,” Sir G. Watt.
London, 1907.

Physiology and Genetics—

“ Studies of Indian Cotton,’’ H. Martin Leake, Journal of Genetics.
IQ1I, etc.

“ The Cotton Plant in Egypt,” W. Lawrence Balls, with Bibliography.
London, 1912.

“* Analyses of Agricultural Yield,’ pts. i.-iii., W. Lawrence Balls
and F. S. Holton. Phil. Trans. Roy. Soc., 1915-16.

Applied Science—

“The Development and Properties of Raw Cotton,” W. Lawrence
Balls, with Supplementary Bibliography of Cotton, p. 221.
A. and C. Black. 5s. London, 1915.

CHAPTER VII

VEGETABLE DYES !

By the late SARAH M. BAKER, D.Sc.
Quain Student in Biology, University College, London

THE art of extracting colouring matters from plants
and impregnating with them animal or vegetable fabrics,
has been practised from the earliest dawn of civilisation.
All trace of the pioneer workers has disappeared, and
within historic time, until the advent of synthetic dyes
in the last generation, no fundamental change was
introduced into the technique of dyeing. Modern
methods are essentially modifications of the primitive
processes still employed in the East, and, although they
reduce time and labour, the quality of the work generally
suffers from such departures.

In the Egyptian wall paintings, garments coloured
scarlet, bright blue, yellow and green, are represented
very early; but the custom of using fine white linen
for mummy cloths has prevented the preservation of
much coloured material. One mummy cloth of about
1000 B,C. has been shown to contain two yellow dyes

1 The lecture on which’ this chapter is based was delivered on
March 12, 1917, and a few days later the manuscript here printed was
handed in by Dr. Sarah Baker with final corrections for the press.
This gifted botanist died on May 29, in her 3oth year.

99

100 EXPLOITATION OF PLANTS

of vegetable origin. Pliny mentions Tyrian purple
(an animal dye), scarlet (probably madder), and yellow
as highly esteemed dyes and very ancient.

The best collection of coloured materials, both of
silk and linen, found by Prof. Flinders Petrie, date from
the relatively modern Roman occupation of Egypt,
A.D. 300-500. The colours used were the soluble yellow
from safflower, several madder colours and indigo, and,
in spite of being over 1500 years old, they are still quite
bright and clear (see Schunk, 1892).

In each of the European countries the dyeing in-
dustry was at first dependent upon indigenous plants,
which were often extensively cultivated to supply it.
An interesting list of indigenous English dye plants,
comprising some ninety species, is given in Mairet,
1916 (p. 38-44), but most of them give such a poor
yield, or are so difficult of collection in quantity, that
they have now no economic importance.

In the sixteenth century several tropical dye plants
were introduced, giving a larger and purer yield of the
same colouring matters. In spite of stringent prohibi-
tions and heavy penalties against dyers using these
“ pernicious drugs,” logwood from South America and
indigo from India quickly supplanted home-grown
products, and were followed by numerous other dye
plants, especially from the tropics.

This influx of new foreign dye plants continued until
the middle of last century. Then in 1858 Perkin pre-
pared mauveine, the first of a long series of synthetic,
dyes produced’ from coal tar. Not, only were many
hundreds of new colours evolved, but two of the most
important vegetable dyes were successfully synthesised,

VEGETABLE DYES IOI

viz. Alizarin (the dyeing principle of madder), about
1870, and Indigo blue in 1870.

The triumph of the chemists brought with it the
usual penalties of progress. The madder industry of
Southern France quickly succumbed before its formid-
able competitor, and whole districts were ruined. The
indigo planters of Natal and Bengal answered the
challenge in a different way. They studied their plant
more intensively, undertook breeding and hybridisation
experiments, and succeeded in materially increasing the
efficiency of production.

At the present time the whole trade in vegetable
dyes is faced with a similar problem. Even where, as
in the case of logwood and the red woods, the natural
dye principle has not actually been synthesised, numer-
ous substitutes of practically equivalent value may be
prepared ; so that the most pressing object for inquiry
is whether there is now any justification for the survival
of the natural dye industries, or whether the. land
bearing dye plants could not be more usefully employed
in other ways.

Before the question can be intelligently considered,
a survey must be made of the most important natural
dyes and their sources.

It is easy to approach the subject under a misappre-
hension. The wonderful brilliance and diversity of
colour shown by flowers and foliage would naturally
lead us to hope that we could borrow some of their
magnificence. But the pigments elaborated by plants
for their own decoration are fugitive and elusive sub-
stances, closely knit with the life of the organism, and
all these are quite useless as dyes.

102 EXPLOITATION OF PLANTS

The colouring matters which serve the dyer are
generally present in the plant in the form of soluble
colourless compounds with various sugars, called
glucosides. The conditions governing their produc-
tion are only vaguely understood ; but it seems prob-
able that they are waste products, which the plant has
no means of excreting, They are found, as a rule, in
the bark of -stems or tubers, or in the leaves. The
number of different plant dyes is surprisingly small,
but each of the principal elementary compounds has a
wide range in the vegetable world. Tropical plants,
on the whole, produce larger quantities of the same dye
than the plants of temperate regions. Beyond this,
and the fact that the Leguminose provide a large pro-
portion of the world’s dye plants, it is impossible to
generalise.

The object of the dyer is to impart a permanent
colour to his fabrics. For this purpose the colouring
matter must be firmly united to the fibres. It is a dis-
puted point whether, in dyeing, this is due to an actual
chemical combination between the molecules of dye and
fabric, or whether it is a physical property of the large
colloidal particles of the material, known as “‘ adsorp-
tion.”” Probably, in most cases, the two effects are
combined and, when the processes of dyeing are slowly
performed, a purely physical adsorption is gradually
followed by chemical combination.

The fabrics may be sharply divided into two classes,
according to their origin from animal or vegetable
sources (mineral fibres, like spun glass or asbestos,
cannot be dyed).

The animal fabrics, wool, silk, leather, feathers, etc.,

VEGETABLE DYES 103

are all built upon a basis of proteins. That is, their
chemical constituents, while very complex, are yet
relatively reactive. They contain groups, analogous to
ammonia and carbonic acid, arranged alternately on
immense chains, many hundreds of atoms long. Each
group in the chain still retains some of its original
qualities ; so that the proteins are capable of acting
either as weak bases or as weak acids, as occasion re-
quires. This is very important from the dyer’s point
of view, for it means that either acid or basic dyes (from
neutral or slightly acid solution) will be absorbed and
held by animal fibres.

The vegetable fabrics, cotton, artificial silk, linen,
jute, hemp, etc., are all composed of cellulose, an
extremely inert carbohydrate which is insoluble in
almost everything and has practically no chemical
affinities. Dyeing upon vegetable fibres is consequently
a far more difficult process, and there are very few dyes
which can be applied to them direct. The most
general special treatment for rendering vegetable fibres
amenable to dyeing is to cause them first to absorb
tannic acid (found in galls, sumach bark, tea leaves,
etc.), and then, upon the tannic acid groundwork, basic
dyes may be applied from a solution made faintly
alkaline by soap, lime, or soda. Acid dyes cannot be
used for vegetable fibres.

The dyes themselves may be roughly classified as :
(a) Direct or substantive, when they are applied with-
out further treatment; (6) Pigment, or vat dyes, when
the colour is developed upon the fibre ; and (c) Mor-
dant, or adjective, dyes when they are ‘fixed by means
of metallic bases.

104 EXPLOITATION OF PLANTS

Among natural dyes there are only three which will
dye vegetable fabrics directly, namely, turmeric, saf-
flower and annatto.

Turmeric is a bright yellow dye, which may be used
for cotton, silk, or wool dyeing. It is made from the
ground-up rhizome of Curcuma tinctoria.

Safflower is obtained from the flower-heads of the
Egyptian thistle, Carthamus tinctoria. These contain
two dyes, a fugitive yellow, which is one of the most
ancient vegetable dyes, and also small quantities of a
bright pink, which was formerly used in all the coun-
tries of Europe to dye red tape.

Annatto comes from the pulpy seed-coat (aril) of the
shrub Bixa Orellana, and gives a bright orange colour.

Since the discovery of Congo Red in 1884, a number
of direct cotton dyes have been prepared from coal tar
with a wide range of colours. They are all fugitive,
and are not fast to hot water; but they are extensively
used for cheap calico printing. The natural dyes,
being equally fugitive, possess no essential advantages
over them and cannot, with their limited colour range,
hope to compete successfully with the synthetic dyes.

Several direct dyes for silk or wool only were formerly
used ; but as they have now been superseded by arti-
ficial substitutes, they need: not be considered here.
There is, however, one interesting group of direct wool
dyes, which might be capable of more extensive exploita-
tion. These are the lichen dyes.

Lichen dyes—In general the dye-producing lichens
are drab-coloured species growing on rocks or trees in
the most exposed places, especially in bleak mountain-
ous districts, or near the sea coast. They occupy

VEGETABLE DYES 105

habitats where no other vegetation could be supported,
and the chief cost of production is the labour involved
in collecting them. It is generally supposed that
lichens grow too slowly to form a satisfactory crop;
but planting experiments have never been system-
atically tried. At any rate, a study in the field of the
successions, in which these economic lichens form a
conspicuous part, would be most interesting and might
even prove profitable.

Two series of dyes have been obtained from lichens.
The beautiful purples and reds, sold as Orchil, Cud-
bear, and Litmus, are obtained from various species of
Roccella imported from the Canary Islands. The colour
is developed by oxidation of the powdered lichen in
ammoniacal liquor (obtained by the peasantry from
stale wine, etc.). The fermentation takes some weeks,
and the mass must be frequently stirred and kept at a
moderate heat. After the oxidation the colour may be
extracted. by alkalis, and the insoluble dye can then be
precipitated as a reddish powder by any acid (acetic or
hydrochloric acids are the ones generally used). The
process can quite easily be carried out on test-tube
scale with a lichen suspected of having tinctorial pro-
perties ; allowing a week in o'880 ammonia for the
oxidation stage.

Although the colours, orchil, cudbear, etc., are not
very permanent, they are of peculiarly beautiful quality,
and are still used by dyers to impart bloom to compound
shades. Similar dyes can be extracted from several of
our native lichens, by analogous treatment. In Scot-
land and the Shetland Islands Lecanora tartarea and
Urceolaria calcarea were at one time collected in large

106 EXPLOITATION OF PLANTS

quantities for this purpose. The collectors obtained
from rd. to 2d. per |b. for the lichen, and could gather
from 20-30 lb. in a day. As the cost of transport of
the bulky lichens from remote districts is heavy, it
would be more efficient for the collectors themselves
to develop and extract the dyes and export them in the
more convenient powder form.

The other lichen dyes can be extracted with boiling
water. They give shades of brown and yellow of great
permanence. They are still used in the Highlands,
where they are known as “‘ crottles,’”” or crotal, and in
the West of Ireland. Parmelia saxatalis and P. ompha-
loides, collected and dried in July and August, are used
to dye woollens for tweeds; the peculiar smell of
Harris tweed is partly due to the use of these lichens.
Ramalina scopulorum also gives a fine yellow brown, and
several other Parmelia species give similar colours.

The dyeing process is very simple. The dried
*crottle ’” and cloth are laid in alternate layers until
the bath is full, cold water is added, the whole is brought
to the boil, and boiled till the colour is strong enough.
Alum is sometimes used to mordant the cloth, but it
does not seem to be necessary (see Mairet, 1916, chap.
on “‘ Lichen Dyes,” also Lindsay, 1855). If the dyeing
principle of crotal could be extracted and put up in
portable form it might prove a useful commercial
product, as the demand for fast brown shades for cloth
is likely to be permanent.

Indigo.—Although direct dyes are simple in applica-
tion, they are usually (with the striking exception of
crotal) rather fugitive, and consequently of limited
applicability. The most permanent kind of dye is one

VEGETABLE DYES 107

in which the colour is not applied to the fibre from
solution, but is developed within the fabric.

The type from which this method of dyeing, known
as “‘ vat dyeing,’’ was derived is the famous vegetable
dye indigo blue. Indigo occurs in the form of a gluco-
side, ‘‘ indican,” in the leaves and berries of a number
of different plants. Sometimes it is associated with a
yellow dye, and the plant yields a compound green.

In England up to the sixteenth century the source of.
indigo was the woad plant Isatis tinctoria. The plant
was cultivated, and gave two crops of leaves in the year.
The dye was developed by a long and tedious process,
involving, first, a slow drying of the pulped-up leaves
rolled into balls, then a damp fermentation lasting several
weeks, and, finally, a second drying. Woad as a dye
plant was superseded by imported indigo extracted
from various Indigofera species cultivated in the tropics.
But the woad industry still survived, on a small scale,
up to the end of last century ; because the addition of
small quantities of woad to the indigo vat was found
to improve the fastness and penetrating power of the
dye, and also to assist in the fermentation process used
in its reduction. An interesting account of a woad
mill at Parson Grove near Wisbech, where the primi-
tive machinery and methods were still used in 1896,
was given by Darwin and Meldola in Nature (1896).

The cultivation of Indigofera in the tropics is, how-
ever, a valuable industry and, as India is the chief
producer, the maintenance of the natural dye is of direct
imperial interest.

In Bengal indigo land is ploughed in October, and
the seed sown in drills the following February or March.

108 EXPLOITATION OF PLANTS

By June the plants are three to five feet high, with a
stem } inch in diameter. The maximum colour is
developed by the end of August, and the young leaves
are the richest. Generally two crops are taken from the
plants, one in the middle of June, the other two to three
months later.

To extract the dye the plants are cut early in the
morning and closely stacked together upright in a large
vat. Bamboo rods are laid across the vat and fixed
down by heavy timber. Water is then run into the vat’
till it nearly reaches the bamboos. The whole is left
nine to twelve hours at a temperature of 30°-35° C.,
while an active fermentation takes place. The whole
mass expands, and high pressures are developed in the
vat, so that the beams are sometimes broken. Mean-
while several gases are evolved, carbonic acid, marsh
gas, and hydrogen; the latter often catch fire and form
a blue flame playing about over the surface of the vat.
The course of this fermentation must be closely watched,
as it is important to stop it at exactly the right point.
After a time the liquid subsides ; then a valve is opened
at the bottom of the vat and the liquid is run out. It
should now be orange yellow or olive in colour, and
contains reduced indigo in solution. It is run into a
beating vat, where a rotating wheel mixes the liquid
with air. Atmospheric oxygen quickly converts the
reduced indigo in solution into insoluble indigo blue,
which comes down as a blue precipitate, until the liquid
is clear. It is collected, dried, and exported in powder
form. The refuse plant or “seet” is valuable as a
manure ; but, curiously enough, it cannot be used direct
for indigo lands, or the resulting crop is poor in the dye.

VEGETABLE DYES 109

The usual plan is to grow some other crop on “ seet”
manure, and return to indigo the next year.

The competition of synthetic indigo caused an out-
burst of scientific inquiry on behalf of the indigo planters,
Several investigators tackled the complex fermenta-
tion process with the idea of improving its efficiency ;
while the experiment of transferring the Natal species
Indigofera erecta into Bengal, where Indigofera suma-
trana had been exclusively used. for 150 years, proved
very successful. The new colonist gave much heavier
yields of the dye up to even double that of the old
species. Evidently the indigo planters- are fighting
their competitors along the right lines, and further work
may result in still greater yield.

In spite of all this activity, synthetic indigo has
steadily encroached upon. the plant product, and in
1914, 90 per cent. of the world’s supply was made from
coal tar, and made in Germany (see Morgan, 1914).
Plant indigo, although it is faster than the synthetic
compound, gives a slightly less brilliant colour. The
synthesis of indigo blue led also to other important
results. By slightly altering the radicles composing it,
a number of other vat dyes were produced. The thio-
indigos gave fine scarlets, while one of the dibrom-
indigos turned out to be the famous Tyrian purple of
the ancients, once extracted at great expense from sea
shells, such as Buccinum and Purpura, and used as the
symbol of regal state.

The process of dyeing with indigo, or any of the
eighty to ninety vat dyes now known, is fairly simple.
The dye itself is quite insoluble in water. There are
two methods of making it soluble. One is to treat with

110 EXPLOITATION OF PLANTS

concentrated sulphuric acid, which converts it into a
soluble blue derivative, capable of dyeing directly.
But this procedure is not satisfactory, as it yields a
fugitive colour.

The most usual method is to reduce the blue dye to
the soluble colourless leuco-compound. This reduc-
tion used to be carried out by means of a complex
fermentation lasting over several days, or even weeks.
The preparation of the reducing vat required great
skill and judgment ; the materials used were stale wine,
dock roots, bran, madder, woad, etc., whilst an even,
moderate temperature had to be maintained. Now-
adays chemical reducing agents are generally used.
The chief of these are: (a) for vegetable fibres, hydro-
sulphite of soda made by the reduction of sodium
bisulphite with zinc dust and lime water, tannic acid
is also added to the vat; (6) for woollens, etc., either
ferrous sulphate, quicklime and water, or zinc dust,
quicklime and water. These vats can be prepared
in from four to six hours; the indigo is then added,
and dissolves in the solution with a yellowish brown
colour.

The cloth is boiled or warmed in the vat for some
time, which may be anything up to a month for navy
blue. Then it is oxidised in the air by various me-
chanical devices. As the oxygen penetrates the fibres
the insoluble blue colour gradually develops there, and
in about twenty-four hours the process is complete ;
then no amount of washing or milling will remove the
colour.

Mordant dyes.—The majority of plant dyes belong to
the third class and require some metallic base or mor-

VEGETABLE DYES III

dant, to fix them to either animal or vegetable fibres.
The mordants usually employed are salts of aluminium,
iron and chromium ; copper and tin salts are also some-
times used, while salts of arsenic or antimony may be
added in small quantities to modify the colour, but are
too poisonous to be used in bulk. There has been a
good deal of controversy about the nature of the action
of mordants, but a few general principles can be safely
formulated.

The dye itself is feebly acidic, and forms soluble
salts with the alkali metals, sodium, potassium, etc.,
but insoluble coloured “‘ lakes ’”’ with the alkaline earths,
calcium, barium, etc., and also with the mordant metals.
To be a successful mordant a metal must first form an
insoluble “‘ lake ”’ with the dye and, secondly, it must

*be what is called an ‘‘ amphoteric electrolytic,” i.e. it

must be capable of making either weak acids or weak
bases. This second property enables the mordant to
form a linkage, partly acidic and partly basic, between
the material on the one hand and the dye on the
other.

The mordant is usually applied in a separate opera-
tion either before or after the dye bath, though very
occasionally the two may be applied in the same bath.
With vegetable fibres, impregnation with tannic acid
must precede the absorption of the mordant, so that
the whole process of adjective dyeing is rather tedious.

One important property of all mordant dyes is that,
by changing the metallic radicle, considerable modifica-
tion in the colour of the dye may be introduced so that,
from a single dye radicle, several distinct colours may
be produced.

112. EXPLOITATION OF PLANTS

The most important vegetable mordant dyes fall into
three groups of closely allied chemical’ substances—the
hematoxylin group, the flavone group, and the alizarin
group.

The hematoxylin group of dyes come from a series
of South American woods used for dyeing under the
names of logwood and the red woods. Logwood is
produced from the hematoxylin tree (Hematoxylon
campechianum). The wood must be matured by age-
ing. To do this chips and raspings are stacked in heaps
20 feet long, 10-12 feet broad, and 3-4 feet high ; water
is added and a fermentation probably goes on. The
process is very touchy, and depends largely upon the
state of the weather; on a warm, dull, foggy day the
whole of the wood may be destroyed, for dyeing
purposes, in a few hours.

The matured chips are exported, and the colouring
principle hematein dissolves out in the dye bath.
Logwood is still used a good deal for dyeing black on
iron or chromium mordants for silk or wool; it also
gives a dull blue with alum mordant and a dingy purple
with tin.

The soluble red woods (Brazil wood, peach wood,
etc.) from various species of Cesalpinia give, in a
similar manner, a closely allied colouring principle
“ Brazilin,’” which gives shades of pinks and purples
with the different mordants.

The insoluble red woo. (barwood, camwood and
saunderswood) contain the principle Santalin, of un-
known composition, which gives very fast shades of
dull red and rich claret brown, which are used for wool
dyeing in compound browns.

VEGETABLE DYES 113

The second group of adjective dyes, the “ flavone ’’
group, include by far the largest number of vegetable
dyes. All these dyes are built upon the same skeleton
“ flavone ’’ with slight modifications in the number and
‘position of the hydroxyl groups in the molecule. They
produce a range of shades of yellows and browns, and
are very widely distributed in the vegetable kingdom.

For yellows the plants generally used were: 1. Weld
from Reseda luteola, once cultivated in France, Ger-
many and Italy. 2. Old fustic, the wood of a Central
American tree Morus tinctoria. 3. Young fustic from
the Rhus Cotinus of Southern Europe and the West
Indies. 4. Quercitron from the inner bark of Quercus
nigra and Q. tinctoria of the United States and Central
America; while the ling, Calluna vulgaris, i is still used
by the Highlanders on an alum mordant. The tips
are gathered just before flowering, boiled in water, and
the liquor used for dyeing.

Although these plants all give fast good yellows,
there are so many cheap yellow synthetic dyes that they
are hardly likely to survive. Fustic wood can still be
bought, and is used for compound shades.

The closely allied brown dyes are more likely to hold
their own because in many cases they give fine perma-
nent colours. Catechu gives a brown on cotton, mor-
danted with copper sulphate and later ‘‘ saddened ” in
potassium dichromate ; which is fast to light, soap, and
even bleaching. It is used also for compound shades
and weighting black silks and woollens. The dye is
obtained from the heartwood of Acacia Catechu or
Areca Catechu from Bengal, and also from the leaves
of the mangrove Ceriops Candolleana. The leaves are

I

114 EXPLOITATION OF PLANTS

extracted in hot water till the liquor is syrupy, the
insoluble matter is strained off, and on cooling, the
pasty mass is cut into cubes and dried. This is known
as ‘ mangrove cutch.”

Other brown dyes, once much in favour, walnut,
alder bark, and sumach from Rhus Coriaria, have now
practically disappeared from use.

The third group of mordant dyes, “the alizarine
group,’’ were formerly the most important of all cotton
dyes. The two associated colouring matters, alizarin
and purpurin, are found in the tubers of several plants.
In Europe the chief source of the dye was Rubia tinctoria,
which was largely cultivated in Southern France.
The colour is present in the cortex of the tubers ; these
were gathered up in their third year, and the plant was
propagated by shoots. The ground tubers were ex-
ported and used in alkaline solution for cotton dyeing,
in neutral solution for wools.

Madder gives a whole series of brilliant and very fast
colours with the different mordants. With alum it
gives the famous turkey red—the fastest known cotton
dye. This red was used by the ancient Egyptians, and
in Turkey and Persia madder is still cultivated for
dyeing hand-made carpets. With chromium madder
gives a rich red brown, with copper a brown, with tin
an orange yellow, and with iron dull purples and a
dingy approach to black.

When the dye is to be used for cotton printing the
patterns are stamped upon the material with different
proportions of the various mordants mixed with tannic
acid. Afterwards the whole piece is passed through
the dyeing bath, when the colours are developed upon

VEGETABLE DYES 115

the mordanted parts only. With well-chosen com-
binations quite pleasing effects can be obtained in this
way.

Artificial alizarin has now entirely superseded madder
for Manchester cotton printing; the colours it gives
are brighter though not quite so fast as those from natural
madder. Also a number of derived alizarins have been
prepared with similar properties, and some of these
complete the colour range by providing colours from
the blue end of the spectrum.

Besides these three groups, which include the chief
textile dyes of the past, there are a few plant dyes of
limited applicability which, like the insect dye, cochi-
neal, have held their own and will probably continue
to do so, because of their harmlessness. One of the
chief of these is alkanet, much used for colouring medi-
cines, pomades, sweets, etc. The real alkanet of the
East is obtained from the roots of Lawsonia alba; in
this country “‘ false ’’ alkanet only is used, made from
the roots of Anchusa tinctoria, a plant cultivated on a
small scale for the purpose. Alkanet gives violet or grey
shades with iron or alum mordants,

These, then, are the most important vegetable dyes.
Every one of them has played a worthy part in the
history of industrial development, and two at least,
indigo and alizarin, have pointed the way to science
in the development of new colour principles. But it
is more important, for present-day practice, to know
how they stand in relation to modern synthetic dyes.
There are always enthusiasts to be found who will up-
hold anything ancient, and who would have us believe
that the road to the millennium leads through the past.

116 EXPLOITATION OF PLANTS

So there are voices even now which advocate a return to
the austerity of vegetable colours and bewail the garish
profusion of the coal-tar products. But they forget
that time can only move forwards; the shadow may
return on the dial perhaps, but it never moves back-
wards. If vegetable dyes have really a part to play
in the future, those who exploit them must go ahead
and keep abreast of the chemical activity of the times.

Certainly vegetable dyes can never hope to compete
in variety of colour and tone with the hundreds of
synthetic dyes, whose numbers increase every year.
Why, even a simple colour like green had to be obtained
by compounding yellow and blue, before the coal-
tar greens were invented. But it is possible that, for
certain standard colours for which there is a steady
demand, and especially where fastness is important,
a vegetable crop may be the most effective source of
supply. This would apply most to the colours possess-
ing heavier radicles—dark browns, blues, purples and
blacks, whose synthesis is always a complex process,

To compete successfully with coal-tar colours the
highest efficiency must be maintained. If possible the
dye principle should be extracted and sold in convenient
form; the bulky dyeing woods, etc., are at a disadvan-
tage in every stage of packing and transport, and
ultimately in the dyeing trough itself. Further, if plant
dyes are to be the standard fast colours in certain shades,
the public should know their names so that, as in the
case of indigo blue, any one can obtain a dye of proved
quality by asking for, e.g., logwood black or cutch
brown.

Another and far more fundamental necessity is an

VEGETABLE DYES 117

intimate study of the dye plant ‘itself—its physiology ;
the production and maintenance of good, pure strain
seed; the best methods of dye development and ex-
traction, etc. The importance of this kind of work is
amply ilustrated by recent work on indigo. If only
the processes leading to dye production in the plint
were really understood, there is very little doubt that
the yield of dye could be greatly increased by suitably
modifying the conditions of cultivation.

There is still another side of the dyeing process,
which is of general application, but affects plant dyes
most especially, and this is the potentialities of new
mordants. The periodic table positively bristles with
elements, closely allied to iron and chromium, ampho-
teric electrolytes, having the chemical properties
appropriate to a mordant, e.g. nickel, cobalt, molyb-
denum, tungsten, uranium, titanium, bismuth, gold,
platinum, and all the rare earths.

Now it is of the first importance, if a plant dye is to
be the standard thing for a given colour or colours, that
exactly the right mordant should be used to bring out
its best qualities. Further, the modification in tone
introduced by a change in mordant often increases the
colour range of a given dye quite appreciably. This
can easily be illustrated by dyeing with alizarin on
some of these theoretical mordants. Most of the colours
produced fall within the usual range, but nickel gives
old gold, cobalt bright yellow, bismuth crimson,
while uranium gives a good heavy black; these are, in
different directions, outside its. usual range. Some of
these mordants, especially the heavier metals in the
chromium group—molybdenum and uranium—have the

-118 EXPLOITATION OF PLANTS

desirable qualities of dyeing evenly and very exhaus-
tively, and imparting weight to the material. The rare
earths are now commercial commodities, and it is a
question which can only be worked out in connection
with technical experts whether the use of some of them
as special mordants for certain adjective dyes may not
enhance the value of the colours produced sufficiently
to justify the extra expense of the mordant.

In general, however, it seems poor economy, while
we are still wholly dependent upon living plants for the
fundamental necessities of food and clothing, to employ
ground for cultivating dyes which we could substitute.
quite well from the vast deposits of fossil plants.

Where dye plants occupy terrain otherwise unpro-
ductive, as in the case of the lichens, mangrove swamps,
trees cleared from tropical forests, and the heather
of oyr own moors, it is to our obvious advantage to
exploit them where practicable. In other cases, e. g.
in the indigo industry, much costly machinery would
be out of action by the suppression of a long-estab-
lished pliant industry. The policy, which seems to be
indicated, is intense specialisation and efficiency in a
few superfine dye crops, and the exploitation of new
dye plants only from terrain which is otherwise of no
economic value.

REFERENCES

KNECHT, Rawson and LoEwENTHAL. A Manual of Dyeing. Griffin &
Co., London.

Rawson, GARDINER and Laycock. A Dictionary of Dyes, Mordants
and other Compounds. Griffin & Co., London.

SEYMOUR ROTHWELL. The Printing of Textile Fabrics. Griffin &
Co., London.

E. M. Matret. Vegetable Dyes. Hampshire Press, London, 1916.

VEGETABLE DYES. Ti

G. T. Morcan. Modern Dyes and Dyeing. Econom. Proc. Roy.
Dublin Soc., ii. no. 8. 1914.

E. Scauncx. Notes on Some Ancient Dyes. Mem. Proc. Manchester
Lit. and Phil. Soc., vol. v. p. 158. 1892.

W.L. Linpsay. The Dyeing Properties of Lichens. Edinburgh New
Phil. Journ., New Series, no. 2, p. 56-77. 1855.

DaRwIN and MEeLpota. Cultivation and Uses of Woad. Nature,
vol. Iv. p. 36. 1896.

Rawson. Cultivation aid Manufacture of Indigo. Journ. Soc. Chem,
Industry. May 1899.

CHAPTER VIII

TEA MAKING

By S. E. CHANDLER, D.Sc., A.R.C.S., F.L.S.
Member of the Staff of the Imperial Institute

From beginning to end the tea industry is replete with
matters of scientific interest. On the agricultural side
the problems connected with soils, manuring, pruning
and plucking—to make no mention of pests and diseases
—have engaged the attention of specialists, with im-
portant benefit to the industry; while, in regard to
tea manufacture, the briefest consideration will show
that the process must rest upon a biochemical basis
which should afford an attractive and fruitful field
for the scientific worker. Similarly, the purely economic
aspect of the industry is of no less interest to the
student than to the commercial man. The changes
that have come over the tea trade during the last
hundred years, both in regard to sources of supply
and development of markets are among the romances
of commerce ; _and at the present moment the rise of
the tea industry in the Dutch East Indies is an
important chapter in the act of being written.

The tea industry, therefore, affords abundant material
for discussion, and in planning a single lecture the diffi-
culty is one of selection of topic. To botanists and

120

TEA MAKING 127

chemists, however, the manufacturing processes have
quite special attractions, and in the present lecture it
is proposed to deal with tea making. In reviewing this
oft-told story it is perhaps natural to begin with the
tea plant in the field, and to follow the leaf until it reaches
the cup. But with some profit this procedure may be
reversed : it is instructive to examine first the finished
product, and the infusion obtained from it, and then
consider what has been done in the way of scientific
inquiry as to the meaning of the processes which
have converted the green leaf into the finished tea—
objects which could hardly be more dissimilar. At
the outset it should be said that modern methods of
tea manufacture cannot be claimed as the direct out-
come of such scientific inquiry; but research has
explained, in considerable measure, their significance,
and thereby furnished fuller possibilities of intelligent
control.

THE TEA INFUSION

It is noteworthy that, whereas the market value of
many commodities is based upon the results of chemical
examination, no tea merchant ever dreams of analysing
his teas with a view to their relative valuation.
Hitherto, chemical methods have not proved suffici-
ently ‘‘ fine ” to discriminate readily, and with certainty,
between those subtle characteristics which separate
one tea from another; and it has been claimed by
the tea man, and conceded by the chemist, that while
chemical analysis will indicate the strength and
astringency of a tea, it tells us little or nothing of
practical value as to the flavour and aroma upon

122 EXPLOITATION OF PLANTS

which so much depends. The methods of the expert
tea taster are well known: full attention is paid to the
appearance and condition of the leaf, but the critical
features are the strength (“ body ”’), astringency, colour
and, above all, the flavour and aroma of a standard in-
fusion which, by simple methods, he makes for himself.
However, within recent years, some very interesting
and suggestive work tends to show that, provided the
chemist pays attention to the relative proportions of the
chemical constituents of the tea infusion rather than to ©
their percentage amounts, the views of the analyst and
of the tea taster have a relationship which is of con-
siderable scientific interest to the one, and gratifying
to the commercial instincts of the other.

The following table, adapted from Kozai (1), gives
an analysis of the dried green leaf of unmanufactured
(Japanese) tea— \

Crude protein 2. . 1 1 «1 4 6 37.38%
Crude“ fibre” 2. 2. 2. 2. 6 6 4. 1004
Total “extract”. 2. 2. . 1... 342
ASH. ob eel 3, BE Ze A ag ee EO
AANNIN: <3: og 30.3 eae SE)
CaFFEINE. . . «6 « « + 33
EssENTIAL OIL . - . small quantity
Soluble in hot water. . 1. ww 50°9

ry
.
+

There is nothing of especial interest in this leaf
composition apart from the three constituents to which
tea leaf owes its market value, viz. the essential oil, the
“tannin” and the caffeine. The essential oil is prob-
ably characteristic; ‘‘ tannin” is a widely distributed
plant constituent ; while, as is well known, the alkaloid
caffeine is of restricted but very interesting occurrence
in the vegetable kingdom. Ina single genus this latter

TEA MAKING ~— 123

substance may be present in one species, and absent in
another ; present in one organ of a plant, and absent in
another ; and occur in varying amounts in the same
organs of different ages. The genus Camellia to which
the tea-plant belongs well illustrates these points :
caffeine is present in C. Thea (tea), but absent in C,
japonica ; while its occurrence in the organs of the
tea plant and in tea leaves of different ages is well shown
by the following figures—

CAFFEINE IN CAMELLIA THEA

1. Leaf (pegnees leaves) . . « . 492%
ae ee } 7 tot 1 337 | Wu Pasquier)

_ (4th, wy ) eo 6 6 6 BAT

. Hairs of young leaves . . . . 2:2

2

3. Sag Ste et eS Sens BP a ed

4. Bar SL Sy GG ae He de . ae
5. Petals ae tee ble Ee Various authorities
6. Twigs Bi SP Beek RS) Ee Re Be GOES

7. Seeds . 8 geet Bp eae a TaN

The essential oil occurs in exceedingly small quanti-
ties (‘006 per cent. in manufactured tea), and, broadly
speaking, the two most striking constituents are the
caffeine and the tannin. We call down blessings on
the former as a stimulant, but look askance at the latter
as an unavoidable evil with abundant powers of gastric
derangement. By happy instinct those who can afford
to do so eschew cheap teas and drink the “ best ”’ (i. e.
highest priced) teas, claiming satisfactory results especi-
ally in regard to tannin effects. We are therefore the
more surprised to find that chemical analysis shows that,
in any one class of tea, the expensive teas commonly
contain in the cup more tannin than cheap teas! e. g.

124 EXPLOITATION OF PLANTS

a cheap Ceylon tea contained 5°46 per cent. of tannin,
while an expensive Ceylon tea gave 7°56 per cent.

Now, the probable explanation of such figures appears
to be forthcoming as a result of investigations carried ©
out in rg1z in the laboratories of the Lancet (2).
Ordinary infusion of tea is a slightly alkaline liquid ;
if just acidified, it becomes lighter in colour, and as it
cools a flocculent precipitate is formed, which can be
brought down more completely by appropriate means.
It is not unreasonable to suppose that these happenings
take place when the beverage reaches the acid contents
of the stomach. An analysis of the precipitate gave the
following results— .

CAFFEINE AND TANNIN IN TEA INFUSIONS

(5 gr. of tea infused for 5 minutes in 4oo c.c. boiling water)

er Mh Approx. ratio
3 Amount of Caffeine in Tannin in .
Variety of Tea. precipitate. precipitate. | precipitate. oe catene to
China... 68 % 72% 5°08 % 123
Ceylon. . . IO-I2 2°53 759 | T3
Indian (Assam) 12°88 3°22 9°66 L3

The table gives the total amount of the precipitate
(estimated on the dry tea); and suggests that, as a
rule, China teas yield it in least amount, and Assam teas
in greatest. Further, the precipitate is composed of
caffeine and tannin in the proportions of 1:3. These
facts led to the view that the precipitate is a definite
compound which may be described as caffeine tannate,
so that we arrive at the inspiring conclusion that
a cup of tea is, broadly speaking, a slightly alkaline

TEA MAKING 125

aqueous solution of caffeine tannate. This latter sub-
stance is bland and smooth to the taste, possessing neither
the bitterness of free caffeine, nor the astringency of
free tannin ; and, in all probability, in this combination
the -physiological effects of the two constituents are
greatly modified. This leads, then, to a new position :
in a tea infusion we may not be dealing with “ free”
tannin and “ free ’’ caffeine, but with a more or less
completely balanced compound of the two. How far
does this prove to be the case¢ A comparison of the
chemical composition of three pairs of teas—Indian,
Ceylon and China respectively—each pair comprising a
cheap tea and an expensive tea, gave the following
results (Lancet, loc. cit.)—

TANNIN AND CAFFEINE IN VARIOUSLY PRICED TEAS

b Tannin | Caffeine
Variety of combined combined Total Total Free Free Broker’s

Tea. with with Tannin. | Caffeine. | Caffeine. | Tannin. Price.
Caffeine. | Tannin.

per cent. | per cent. | per cent. | per cent. | per cent. | per cent.| per Ib.
Indian .| 9:40 3°10 9°50 4:00 0-90 oro |1/rodd.
Indian .| 7:20 2°40 8-73 3°20 0-80 1°53 | «r1dd.

Ceylon .| 9:00 3°00 8-40 360 0-60 —_ 1/4d.
Ceylon .| 6:84 | 2:28 714 3°04 0°76 o-30 | rodsd.
China .| 4:86 162 4°60 28 r18 — 1/5d.
China .| 4:02 1°34 3°02 1°92 058 — 64d.

The figures indicate that—

1. Indian teas may be expected to contain more
caffeine tannate than Ceylon and China teas (first two
columns).

\

126 EXPLOITATION OF PLANTS

2. In any one class of tea, the higher priced sorts con-
tain more caffeine and tannin than the cheaper sorts.

3. Taking two teas of a single class, one smooth and
pleasant to the taste, and expensive; the other harsh
and astringent, and cheap: then the former tea has its
tannin and caffeine in balanced combination with little
or no surplus of free tannin ; while the cheaper tea has
a relatively much larger surplus of uncombined tannin,
resulting in the harsh astringency characteristic of its
class. This is well seen in the Indian and Ceylon
teas; with China teas it is noticeable that, so far
as the above analyses indicate, they seldom give any
free tannin ; but, per contra, usually-possess a relatively
higher percentage of uncombined caffeine, which fact
probably accounts for the pleasant bitterness of many
China sorts. There would appear to be evidence for
supposing that in China teas the caffeine has relation-
ship with some constituent other than tannin.

Summing up: as regards Indian and Ceylon teas,
at any rate, it seems that in good quality, high-priced
sorts, there is comparatively little uncombined tannin ;
in low priced sorts, a notable surplus. On the
other hand, most good teas contain caffeine in some
excess. Further, teas of higher value contain more
total caffeine and tannin (i. e. beverage making material)
than cheap teas, and in practice actually may prove to
be more economical, as well as more wholesome than
cheap teas.

TEA MANUFACTURE

We may now refer to the processes of manufacture
which result in these interesting complications. The

TEA MAKING 127

most important tea in the world’s markets to-day is
black tea, and the manufacture of this variety will be first
described. As is well known, the modern manufactur-
ing process obtaining in India, Ceylon and Java are
ultimately based upon the Chinese practice, but the
genius of the engineer has virtually eliminated hand
methods and produced a cleanly efficient system of tea
making. There are four chief manufacturing processes
between the plucking of the green leaf and the final
appearance of the finished tea. They are—

1. Withering.—The freshly plucked leaf is brought
into the withering house, and spread in a thin layer on
clean floors ; or, more commonly, on light shallow trays
(made of hessian cloth, wire netting or bamboo) arranged
on racks. The process is complete when the leaf is
soft and wilted—‘‘ withered ”"—and at a temperature
of 80° F. it occupies eighteen to twenty hours, though
in the cooler hill districts of India a longer period
is necessary. Since withering must in large measure
depend upon uncertain conditions of weather, it is not
surprising that special withering machinery affording
regular conditions of temperature by means of currents
of warm air is also in use. The next step is—

2. Rolling, in which the flaccid leaf is partially bruised
and crushed, becoming twisted in the process. Carried
out by hand (and foot) methods, this process gave
offence to the esthetic sense of the European, but in the
modern rolling machine the leaf is untouched by hand.
Fed from a hopper into the cylindrical metal ‘‘ jacket,”
which travels eccentrically over the surface of the
“ rolling-plate,” the leaf is rolled on the latter under
adjustable pressure. The plate may be fixed, or itself

a

128 EXPLOITATION OF PLANTS

have a differential motion in regard to the jacket. In
due course the leaf is discharged from the machine,
the process occupying from fifteen to sixty minutes,
according to type of machine employed, character of
leaf, and size of charge. Short periods of rolling con-
stitute “light” rolling; longer periods, ‘‘ heavy’
rolling. After a sifting, and a re-rolling of older leaves,
the next stage is the—

3. Fermentation —When small quantities of leaf are
dealt with, the leaf is placed on shelves, or in trays
arranged in racks ; but in large factories special ferment-
ing floors, made of cement, tiles or even plate-glass are
employed, the twisted ruptured leaf being spread out
in thin layers one or two inches deep to give full access
to the air, which should be freely admitted. The
optimum temperature is about 80° F., and the atmo-
sphere is kept moist by means of suspended wet cloths.
Similar cloths are also arranged over but just clear of
the leaf. The floors, cloths and everything connected
with the fermenting house (which is kept relatively cool
and darkened) should be maintained scrupulously clean
by frequent steaming and scouring, to prevent the
growth of putrefactive bacteria, which are very detri-
mental to the production of good-class tea. During the
fermentation, which lasts a few hours (but may be much
shorter), the leaf changes colour, and gives evidence of
becoming tea as distinct from leaf. When the fermen-
tation is complete, the final major operation takes place,
the so-called—

4. Firing.—This process, originally effected over open
charcoal fires, is now carried out entirely by automatic
machinery. The tea is fired or dried by means of hot

TEA MAKING "129

air. The “ drier” consists essentially of an air-heater,
and a.drying-chamber through which hot air is drawn
over the tea by means of an exhaust fan. The tea is
carried slowly through the chamber on a series of
moving perforated metal tables arranged one over
another and so constructed as to resemble endless roller
shutters. The motion of the individual tables is such
that the tea travels from the top of the chamber to the
bottom, where it is discharged. The temperature of
the air entering the drying chamber is usually between
220° F. and 240° F., but when the firing is about
three-quarters completed, the temperature is lowered to
180° F. or 200° F. The time required for the drying
is usually about twenty-five minutes.

With the completion of the firing the tea is made.
Subsequent processes of grading, ‘‘ equalising,” packing,
etc., need not be considered here, except to mention
that previous to packing, the tea is subjected to a final
firing to complete the drying.

THEORY OF TEA MANUFACTURE

It will be obvious that the key-phase of black tea manu-
facture is the fermentation process. Indeed, it is recog-
nised that virtually everything prior to fermentation is
tributary to that process, and adapted to give it full scope;
while the subsequent stages of manufacture are to control
the fermentation and take full advantage of its results.
The scientific work which has established this position is
due chiefly to the following British and Dutch chemists,
viz. Bamber, working in Ceylon ; Mann and Hope (3),
of the Scientific Department of the Indian Tea Associa-

K

130 EXPLOITATION OF PLANTS

tion; and Naaninga, Welter and Bernard (4), working
in Java at the Government Proefstation voor Thee.
To these should be added Kozai, a Japanese investigator,
whose work has been already quoted.

The work of these chemists (and notably the British
representatives) has shown that the most important
change taking place in the fermentation process is in
regard to the tannin. This substance becomes slightly
oxidised, forming brown-coloured products which
unite with the caffeine present; the significance of
spreading the leaf in thin layers on the fermenting floor,
and arranging for free access of air, is therefore at once
clear. Further, it has been demonstrated that the colour
and body of an infusion of tea depend upon the propor-
tion of tannin oxidised ; the more complete the oxidation
(“ fermentation”) the more colour and body. But
the consumer demands a certain pungency in addition
to these qualities, and pungency depends upon the
relative amount of tannin left unoxidised. Here it is
that the skill and experience of the practical planter
comes in to decide how far the fermentation is to be
allowed to go. During the process the leaf assumes a
fine copper tint, and the characteristic odour of tea is
developed; these are the criteria upon which the
planter’s judgment is based.

The main object of the fermentation would thus
appear to be the oxidation of the tannin, Another
change of much practical significance, and already hinted
at, also takes place, and will be referred to below.

The actual mechanism of the oxidation process has
given rise to much discussion, and there have been the
three inevitable theories. Bamber, in 1893, put forward

TEA MAKING 131

the chemical theory, ascribing the fermentation changes
to. direct union of the tannin of the cell-contents
with the oxygen of the air. In 1900, however, he
described the presence, in the cell-juices, of an (oxidis-
ing) enzyme through whose agency the union of the
tannin and atmospheric oxygen is effected. This
enzyme theory was later confirmed by Mann, Naaninga,
and Newton (the last-mentioned giving the name
“thease to the enzyme), and has since found wide-
spread acceptance. It occasioned much interest and
surprise, therefore, when Bernard, in 1911, revived the
micro-organism theory. As far back as 1891 Kozai had
attributed the fermentation changes to the action of
bacteria, but his views had given way in the face of
Bamber’s work. The special attraction of a micro-
organism theory is readily understood; there is the
question of the distinctive qualities of a tea being due to
specific races of organisms, with all the possibilities of
inoculating inferior grades of leaf with artificially-
obtained pure cultures of the organism found associated
with good tea. Bernard’s organisms are not the bacteria
of Kozai, but yeasts which he finds invariably present
on the surface of the living tea leaf. Some very arrest-
ing observations are made by Bernard, but the case
would not appear to be yet fully established ; so far as
the writer is aware, no practical application of the theory,
‘on a commercial scale, has yet been attempted.

In the light of the fermentation process, the object
of rolling the leaf, apart from the production of a satis-
factory ‘‘ twist,”” becomes clear. We have outside the
leaf the atmospheric oxygen, and within the leaf-cells
the oxidisable substance (tannin), together with the

132 EXPLOITATION OF PLANTS

enzyme through whose agency the oxidation can be
brought about. The partial crushing of the leaf brings
these three elements into contact; the cell-juices are
brought to the surface of the leaf tissue, which acts as
a sort of sponge, allowing of penetration by the air.
Further, there can be no surprise that “‘ fermentation ”
actually commences during rolling. We see, too, the
meaning of discrimination in rolling. In light rolling,
less juice will be expréssed and relatively less fermenta-
tion probable, with the resulting tea infusion light in
colour, lacking in body, but comparatively pungent
owing to the proportion of unfermented tannin; with
hard rolling, more juice is expressed and oxidised, and
the infusion is relatively less pungent, but ae
greater colour and body.

Then as to the withering. If fresh, turgid feat were
jammed into the roller, the leaf would become disinte-
grated with the production of a leaf-mash rather than a
“ leaf-roll.”” With a velvety, flaccid leaf, however, a
“twist” is obtained that will appeal to the purchaser, and
an evenly distributed rupture of the leaf-cells, which
should promote an even fermentation. These were
once considered to be the only objects in withering, but
Mann and others have shown that, so long as the con-
ditions of temperature and moisture remain satisfactory,
the oxidising enzyme greatly increases in amount during
the withering. Not only this, but the essential oil, to
which the tea owes its aroma, increases during withering
by about 15 per cent.; and this increase rises still further
during rolling, and reaches its maximum during fermen-
tation, constituting the second of the important changes
accomplished in that stage of manufacture.

TEA MAKING 133

It will be readily understood that the chemical matura-
tion involved in the processes described will demand a
certain period of time ; and in abnormally dry weather
the leaf may be ready, physically, for the roller before
it is chemically mature ; in wet weather the reverse may
be the case. It is mainly these difficulties which have
resulted in the use of the withering machinery referred
to above.

The withering and rolling, therefore, are preparatory
to, and culminate in the fermentation. There remains
to be considered the object of the post-fermentation
process, the firing. It is known that if the fermentation
is allowed to proceed too far the pungency of the tea is
unduly diminished owing to the reduction of the re-
siduum of unoxidised tannin, to which pungency is due.
The object of the firing, therefore, is to arrest the action
of the enzyme in time. At the right moment the fer-
menting leaf is transferred to the dryer and its tempera-
ture raised to a point sufficient to destroy the enzyme
and arrest the chemical action resulting from its activity.
Incidentally, the tea is dried. The process must be
carried out rapidly and stewing of the leaf at relatively
low temperatures avoided, otherwise the leaf loses
quantities of ‘“ soluble matter” by the decomposition
of the tannin, and pungency suffers for the same reason ;
further, the flavour is reduced owing to the volatilisa-

tion of the essential oil.

OTHER TEAS

The above remarks have reference to the manufacture
of black tea, the standard tea in the markets of this

134 EXPLOITATION OF PLANTS

country. In other countries, however, an important
place is held by other varieties of tea, the chief being
green teas, oolongs, brick teas, and the unique Leppet
tea. In the space available the manufacture of these
teas can be referred to but briefly.

Green teas.—Black and green teas were known in this
country long before any attempt was made to establish
the relationship between them. Misled by informa-
tion supplied with botanical specimens from China, the
botanist Hill, in 1759, explained the two products as
being derived from different varieties of the tea plant,1
viz. Thea 1 Rohea, yielding black (‘‘ Bohea”’) tea; and
T. viridis, yielding green tea (5). Hill’s explanation
held place for nearly a century, until it was finally
disposed of by another botanist, Fortune, who in
1847 described the manufacture of the two teas, as
witnessed by him in China, as from one and the same
variety of plant. Curiously enough, the true explana-
tion had been previously published by Bontius (1631)
and Lettsom (1799), but their accounts had been
overlooked.

As is well known, the differences between black and
green teas result solely from differences in methods of
manufacture. Whereas in the case of black tea, every-
thing is done to promote enzyme action (fermentation)
up to a certain point, in the manufacture of green tea
the essential feature is the prevention of fermentation
by the destruction of the enzyme as soon as possible
after plucking the leaf. In China and Japan (where
most of the green tea is made) the method employed is

1 The tea plant was originally described by Linnzus in 1737 under
the name of Thea sinensis.

TEA MAKING 135

that of heating the leaf in metal pans over fires in simple
furnaces ; in India and Ceylon, where a little green tea
has been made for the Russian and American markets,
the agent used is steam under pressure. In green teas,
therefore, the tannin constituents remain practically
unoxidised, and the liquor possesses less colour and
body, but greater pungency, the latter feature being
characteristic of this class of tea.

Green tea is subjected to a light rolling after firing,
not with the object of rupturing the leaf-cells, but to
impart a “‘ twist.’’ The tea has a soft, silky feel, quite
distinct from that of black tea. During manufacture
it becomes sticky, especially in the case of the youngest
leaves which adhere in small balls to form “ gun-
powder.”

Oolongs.—North America absorbs practically the
whole of a remarkable tea exported from Formosa, viz..
the famous Formosa oolongs, which in recent years
have made considerable but not very successful efforts
to enter the English market. The chief characters of
oolongs are a distinctive delicacy of flavour, and light-
ness of body and colour suggesting green teas, but an
absence of marked pungency. So considerable is the
value of the American market for this class of tea that
in 1904 a special mission on behalf of Indian and Ceylon
planters was despatched to Formosa to investigate the
industry with a view to the production of British-grown
oolongs. The information gained was of much interest,
but no practical results followed.. It was found that
much of the character of the tea is due to a special
feature of its manufacture, viz. a partial fermentation,
effected during a prolonged withering, previous to roll-

136 EXPLOITATION OF PLANTS

ing; but that the chief factor is the special jat (variety)
of plant cultivated—a jat unknown in India or Ceylon,
and calling for such cultural treatment as renders its
cultivation in those countries impossible. That the
natives themselves are fully aware of the importance
of the jat, and of the necessity for keeping it true
to type, is evidenced by the fact that, while in every
other tea-growing country the bushes are normally
propagated by seed (with the attendant possibilities of
variation, hybridisation, etc.), in Formosa all but the
inferior oolong plants are propagated vegetatively, by
layering.

The importance of the jat as a factor affecting the
quality of the Formosan teas is.a reminder that it would
be misleading to suppose that the processes of manu-
facture alone influence the character of the resulting
tea. The case has been stated thus: “‘ A correctly
grown tea plant provides the possibilities of a good tea ;
it is the aim of good methods of manufacture to realise
these possibilities to the fullest extent.’’ Apart from
their effect upon yield of leaf per acre, it is well known
that differences of jat, rainfall, elevation; differences
of soil, manuring, and even type of pruning have their
effect on the quality of the final product, and are taken
into the fullest consideration by the practical planter.

Brick teas— These famous teas form an important item
in the Chinese trade, and are of two distinct kinds,
differing in methods of manufacture, physical characters,
and manner of domestic use. The first class comprises
the brick (and tablet) teas destined for the Russian
markets. These teas are no more than the dust and
siftings of ordinary black and green teas compressed

TEA MAKING 137

into slabs, originally with the intention of economising
bulk in the prolonged and difficult overland transport
between China and Russia. The material used in the
process is obtained chiefly from China, but considerable
quantities of tea dust are now exported from India,
Ceylon, and Java to Hankow, where the factories (under
Russian control) are situated. In making the bricks
the sifted tea dust is steamed and then poured into
wooden moulds in which it is subjected to hydraulic
“ pressure. The bricks weigh from 1} Ib. to 2 lb. each,
and are remarkably hard, smooth and tough; they are
marketed under the trade-mark of the exporter, stamped
upon them while in the press. Tablet teas are essentially
brick teas put up in smaller sizes weighing each a few
ounces.

The second type of brick tea is that manufactured by
the Chinese for Tibet. This remarkable product (which
is made in Szechwan) was investigated by Hutchison
in 1905 on behalf of the Indian Tea Association. Tea
leaf, and not dust, is used. Very rough material, how-
ever, is employed for the average qualities, leaf-stalks,
small twigs, and even clippings of the bush being
utilised, This coarse “ pluck ’’ is heated in iron pans
for a short period, then subjected to a light hand-rolling
and subsequently allowed to ferment for the long period
of three or four days, when the leaf is dried in the sun.

No chemical investigation of this process has been
made, but it is evident that such should prove of con-
siderable interest. In making the bricks the fermented
“leaf ’’ is steamed, and while moist rammed lightly into
wooden moulds, its adhesion being assisted, in the
coarser qualities, by the addition of rice paste. The

138 EXPLOITATION OF PLANTS

bricks are finally wrapped in paper and packed in hide-
covered bales. They differ:much from the hard, black
Russian bricks, being readily broken up into a loose
mass of twigs and leaves. Their domestic application
is also different ; the Russian brick is used for ordinary
infusions, but the Tibetan article is boiled with butter,
salt and other materials to form a soup.

Leppet (Letpet) tea.—Probably the most interesting
of the applications of the tea leaf is in the manu-
facture of the leppet tea of the Shan States and neigh-
bouring districts of Burma. The product does not
enter into external commerce. Two methods of pre-
paration are described. West of the Irrawaddy the leaf
is softened in boiling water and then rolled and allowed
to cool. It is then rammed into a length of bamboo
retaining one of the natural diaphragms, and the end
plugged. The bamboos are then inverted to drain
away moisture, and finally buried in the soil for the
leaf to mature. Eastwards of the river a different
process is employed, though the principle remains the
same. The softened and rolled leaf is tightly packed
into a pit in the ground, lined with boards or matting,
and pressure applied by piling heavy weights on a cover
placed over the leaf. In due course the leaf assumes a
yellow colour, when it is ready for sale.

As in the case of Tibet brick teas, leppet is not used
for making a beverage. The cured leaf is eaten direct
as a vegetable, or mixed with garlic, oil and salt to form
a kind of salad.

It will be evident that the process of manufacture has
little or nothing in common with that of ordinary black
or green teas. In both methods employed one is

TEA MAKING 139

reminded of the ensilage of green fodder so largely
carried out in certain countries, and it is not improbable
that the chemistry of the fodder silo and the leppet pit
and bamboo tube would have features in common.

REFERENCES TO LITERATURE

(1) Koza1, Y.: ‘Researches in the Manufacture of Various Kinds
of Tea.” Imperial College of Agriculture and Dendrology,
Tokio. Bull. No. 7 (quoted in Thorpe, Dictionary of Applied
Chemistry, 1913, vol. v. p. 426).

(2) ANonyMous: “ The Chemistry, Physiology and Esthetics of a
Cup of Tea.”” The Lancet, 1911, pp. 86, 1573.

(3) Mann; Hope: Several important papers in the publications of
the Scientific Department of the Indian Tea Association, Calcutta
(1901 onwards).

(4) NaaNninca; WELTER ; BERNARD : Mededeelingen van het Proefstation
voor Thee. Buitenzorg: Departement van Landbouw (1908
onwards).

(5) Watt: “ Teaand the Tea Plant.’ Journal of the Royal Horticultural
Society, 1907, 32, p. 64. pe

See also CHANDLER and McEwan : “ Tea: its Cultivation, Manufacture
and Commerce.”’ Bulletin of the Imperial Institute, 1913, xi.

p- 252.

CHAPTER IX

THE PLANT AS HEALER
By ETHEL N. THOMAS, D.Sc.

NOTWITHSTANDING that the supreme importance of
the plant’s contribution to human sustenance over-
shadows even its rdle as healer, the consideration of the
medical virtue of the plant needs no apology. The
nation, still less an army, could hardly continue to exist
if unarmed against the depredation of disease. Of the
South African War it has been said that the fly -killed
more than the sword, the disease carrier was more
effective than the bullet carrier.

Though, indeed, prevention is better than cure, as
Peace is better than War, yet peace is not always possible,
and health is not always possible, so that we dare not
yet, in either case, despise the weapons of defence.

Every one is familiar with the wonderful cures effected
recently in the most devastating form of tropical dysen-
tery, by means of special preparations of the drug emetin
obtained from the root of ipecacuanha. The effects
of quinine, a preparation of cinchona bark, are of such
importance in the tropics that the Government long
since arranged that it should be available in small
quantities at every post office throughout India. Its
use is so general, that after the failure of coffee in Ceylon

140

THE PLANT AS HEALER 141

quinine became for the time the great export. The
use of morphia, in the last resource, for the relief of
human pain renders the poppy a plant of price, while
through all ages mankind has looked to plants for the
alleviation of suffering.

It is a matter of great interest and of no little import-
ance to ascertain the means whereby man has become
acquainted with the existence and properties of drugs.
Many are the strange legends of miraculous and semi-
divine instruction. We cannot doubt that from all
time knowledge has been built up as the result of experi-
ence gained through the exercise of that ‘ divine”
curiosity which results in the knowledge of good and
evil, of life and death.

Like all knowledge it gave power, and hence was
not lightly parted from, so that we find the subject from
earliest times deliberately surrounded with that mystery
which has not wholly departed from it. The combina-
tion of the healing art with priestcraft in ancient Eygpt
and other countries is, therefore, not surprising, and
Hermes, the companion of Osiris and Isis, is credited
with the production of a vast series of medical works.
This legend was repudiated later by Galen in the second
century.

Among the Greeks the fame of AEsculapius was tradi-
tional, and the names of his daughters, Hygeia and
Panacea, stand for Prevention and Alleviation to the
present day. He perished, like many others, through
too great a manifestation of power.

Eight hundred years later (466 B.c.) we come to Hippo-
crates, the first authentic written source of medical lore,
with some four hundred “‘ simples,”’ or herbs, of healing

142 EXPLOITATION OF PLANTS

value, and Materia Medica may be said to be established
with Dioscorides in the first century A.D.

By this time physicians are distinct from herbalists,
who, however, frequently took upon themselves curative
work, and who, in any case, were much respected
botanologoi. The botanologoi, alas, hedged round their
trade with darkest superstition, and we read of the
scream of the mandrake as it is drawn from the ground,
the inoffensive rhizome being deceptively trimmed to
resemble the human form before it is allowed to be seen
of the people.

It was the botanologoi who established the foundations
for the science of botany, for the philosophical specula-
tions of Aristotle and Plato proved less productive of
knowledge than the observations, simple though they
were, of the herbalists, who were ultimately driven
through the exigencies of their trade to note and faith-
fully describe the characteristics of their stock.

The great herbals of the fifteenth and sixteenth cen-
turies gave rise to the pharmacopeeias, on the one hand,
and the floras on the other.

Both the knowledge of plants and of their uses seems
to have needed improvement, for Bacon writes, ‘‘ Medi-
cine is a science which has been more professed than
laboured, more laboured than advanced, the labour
having been, in my judgment, rather in circle than in
progression. I find much iteration, but small addition ”;
and Turner, who has been called the Father of British
Botany, dedicates his herbal to Elizabeth with the
words, ‘‘ Such was the ignorance in simples that I could
get no information on the subject, even from the
Physicians.”

THE PLANT AS HEALER 143

So much for the Art, what of the actual vegetable
medicines used ¢

I have chosen a few from the list attributed to
Hippocrates, and it is most interesting to find that
these are still in great request—

Plant Natural Order. General action.
Marsh Mallow Althea officinalis Malvaceez Demulcent, emollient
Hemlock Conium maculatum Umbellifere Sedative, anodyne
Henbane Hyoscyamus niger Solanacee Narcotic, anodyne
Hyssop Hyssopus officinalis Labiate Stimulant, pectoral
Mandrake Mandragora Solanacee Sedative narcotic

officinalis
Mandrake Podophyllum Berberi- Hepatic and intestinal
(American) peltatum dacez stimulant
Mints Mentha Labiate Expectorant, emetic
Mugwort Artemisia vulgaris Composite Diaphoretic
Pennyroyal Mentha Labiate Carminative,
diaphoretic
Poppy Papaver somniferum Papaveracez
Castor Oil Ricinus communis — Euphor- Purgative
biacee
Spurge Euphorbia Euphor- Anti-asthmatic
biacee
Tarragon ae dracun- Composite Stimulant
’ culus
Willow Salix Salicacez

Judging from instructions on ancient papyri, etc., it
seems to have been the fashion to administer compounds
of as many “‘ simples ’’ as possible, and this is still the
custom in the herbalist prescriptions of the present day,
though the more recognised medical practice is in the
contrary direction.

The poppy, the source of opium, was undoubtedly
cultivated in Mediterranean regions at a very early date,
and although it is doubtful whether Hippocrates really
used the poppy as we know it, Dioscorides most certainly
did. Galen states that he only used it for very urgent

144 EXPLOITATION OF PLANTS

cases, but it seems certain that much of the fame of
Paracelsus at a later date was due to his bold use of
opium. In the seventeenth century it was much
recommended, but Hoffman thought that later it was
abused.

At the present day it is grown largely in Turkey,
Persia and India, and the inspissated juice from the
unripe capsules exported as “ ball ’’ opium, from which
the more liquid part has drained away.

The plant is an annual whose seed is sown in October,
preferably in rich, dark, sandy loam, or heavily manured
light clay, and the harvest culled some seventy-five
to eighty days later, That grown in India has only
recently been used in London for medical purposes,
and undoubtedly the Turkish and Persian product is
superior. 7

Castor oil, a native of India, has been found in
Egyptian tombs, and was known to the Greeks. Like
so many medicines of the time, it was chiefly used
externally. . It fell into disuse at one time because of a
drastic element which, however, is not present in the
properly extracted drug, which then constitutes an
excellent mild purgative.

The henbane of the ancients was probably Hyoscyamus
alba, which is particularly recommended by Dioscorides.
It was very much used as a narcotic in the Middle
Ages, but fell into disuse at the end of the eighteenth
century, and was only revived through the experiments
and recommendations of the famous Viennese, Storck,

Several members of the Solanacez have similar proper-
ties, thus Datura Stramonium may have been known to
the ancients as a poison, but Dioscorides undoubtedly

THE PLANT*AS HEALER 145

confused it with henbane, and Atropa Belladonna cannot
be identified with certainty in the writings of the
ancients. Datura Tatula serves the same purpose, and
quite recently an ethnological report on certain Indian
tribes, comments on their use of Datura Metel.

Aloes, familiar in the Bible, was known to the Greeks
400 B.C., and there are many interesting legends as to
its value and trading in the time of Alexander, who
caused it to be improved by cultivation in the island of
Sokotra, from which supplies are still obtained, though
many of the old plantations are now in disuse, since the
introduction of the plant to the West Indies, etc. The
quality of the bitter purgative juice depends largely
upon care in the process of inspissation, and carelessness
accounts largely for the inferior quality of South African
aloes.

The very important plant Digitalis (foxglove) seems
not to have been introduced into medicine until the
Middle Ages, perhaps partly because it is a native over
the greater part of Europe, including Great Britain,
flourishing on siliceous soils, and knowledge up to that
time was derived from the East. The Welsh physicians
of 1200 seem to have used it, though it was not named
until 1542 by Fuchs.

It was regarded at this period as a violent drug, and
it was not until after the investigations in 1785 of
Dr. Withering, a botanist and physician of repute,
that it became established as a heart sedative of great
value. /

The history ofthe cultivation of Ipecacuanha con-
‘stitutes an interesting page in therapeutical and botanical

lore. A native of Brazil, it was in common use in that
L

146 EXPLOITATION OF -PLANTS

country, but did not get a trial in Europe until towards
the end of the seventeenth century. At first, as so often
happens, it was brought into disrepute by ignorant
use. Helvetius, however, established its fame for the
treatment of dysentery by employing it as a secret
medicine, and ultimately secured the sole right of
vending it.

Its widespread use was followed by an astonishing
drop in the death-rate from dysentery in India. The
consequent high price made it desirable in the middle
of the nineteenth century to attempt to cultivate it.
This met-with poor success, until vegetative propagation
from the rhizome and even from the petiole, was estab-
lished in the Botanic Gardens in Edinburgh, and seeds
obtained by suitable cross fertilisation.

Of late years progress has been made in the manu-
facture of suitable preparations of the most active
principle emetin for injection, and quite recently the
intensified study of dysentery necessitated by the war
has resulted in the production of a non-emetic double
salt which can be taken per os.

Quinine, although indigenous to South America, like .
ipecacuanha, is in marked contrast to it in that it is found
on the west of the continent, is a denizen of mountainous,
not swampy, regions, and seems to be quite unused by
the natives. The travelling doctors, descended directly
from those at the time of the Incas, never carry it in
their wallets, and there is great dislike to its use apart
from dyeing. Nevertheless, it was through an Indian
cure by means of red bark that it was introduced into
Europe by the Countess Cinchon, whose name was
later given to the plant.

THE PLANT AS HEALER 147

The subsequent depredation of the South American.
forests necessitated the cultivation of cinchona, which
was ultimately established, with some difficulty, in India
and Ceylon. Its introduction in the latter place proved
an immense boon to planters ruined by the spread of
coffee disease, but over-production has reduced the
price to such a point that it can scarcely now be grown
at a profit in Ceylon.. The more scientific methods of
the Dutch have, moreover, given Java a practical
monopoly.

The pharmacists of the sixteenth and seventeenth
centuries were very naturally constantly attempting to
extract the “‘ quintessences’’” of the medicinal plants,
but it was not until the early part of the nineteenth
century that much progress was made.

In 1816 Serturner isolated an alkaline base morphium,
“a remarkable substance, which shows much analogy
with ammonia.” Vaquelin had already in 1812 extrac-
tracted daphnine. In 1820 Pelletier and Caventou
cleared up the question of quinine, and in 1821 Robiquet,
while looking for quinine in coffee, discovered caffeine.
The isolation of strychnine, codeine, emetin and
atropine soon followed.

The synthesis of urea in 1828 and the consequent
breakdown of the artificial line between inorganic and
organic compounds, together with the isolation of
aniline from indigo, on the one hand, by a pharmacist
in 1826, and from coal tar, on the other, in 1834, led
to the synthesis of certain of the alkaloids, beginning in
the eighties with conine (active principle of hemlock)
by Madenberg. They constitute, from a chemical
point of view, a patallel series to the aniline dyes built

148 EXPLOITATION OF PLANTS

up on other bases derived from coal tar, and hence from
fossilised plants.

Cocaine and Piperine (01)
Piperine (’94)
| i Nicotine (’03)

| ip
a
Dyes Conine (’86) “(Quinine :
“| Cinchonine Papaverine,
[fo Strychnine) | etc.
Aniline Pyridine Quinoline 7,
a | ge “a Isoquinoline
7 Coal Tar.

The accompanying table shows the coal tar bases of
séveral familiar alkaloids. Those from the pyridine
base have already been synthesised at the dates given.

The quinoline derivatives have not yet been synthe-
sised.* They are more complex even than the pyridine
alkaloids, and include quinine, strychnine, ete.

These results are of the first importance, both theoreti-
cally and practically, as they pave the way for the better
understanding of the action of the drug. We are still
very far, however, from being able to correlate chemical
constitution and physiological action. The tentative
suggestion that the presence of OH groups is associated
with antiseptic properties, and of NH, with narcotic
properties, is not always supported by clinical experi-
ence—notably in the sulphonal series, in which nar-
cotism does not increase according to expectation with
the number of ethyl groups present in the substances.

Synthesised drugs are sometimes cheaper than the
natural product, but, on the other hand, even the

x

THE PLANT AS HEALER 149

chemically isolated principle, still less the synthesised
product, may be much less successful in the hands of
the clinician. Thus aloin is much more uncertain in
its action than the crude drug aloes,’and the synthesised
salicin compounds are very difficult, practically impos-
sible, to purify from phenolic associates.

‘It seems as though in many cases the total action of a
drug is due to the interaction of several components,
some known and some, it may be, unknown, This is
paralleled by the reinforcement which seems to take
place in mixtures from several plants having practically
the same properties. Such mixtures have been proved
to be more effective than a corresponding strength of
any one, and they form a justification for old-fashioned
multiple compounds, now fallen into disrepute in
orthodox medicine. The explanation of phenomena
of this kind will, no doubt, ultimately be found in the
realm of Physical Chemistry, as it is very probably a
question of solubility.

It is as well, therefore, perhaps, that most vegetable
drugs are still manufactured from the plant, and con-
sequently there is a vast industry in medicinal plants.

_Both medical men and herbalists use large quantities

of—
Balm Penny Royal

Comfrey Rue

Feverfew Southernwood
Celandine Tansy
Woodsage Wormwood
Marsh Mallow Yarrow, etc.

It must be remembered that while the tendency of
orthodox modern medicine is to limit more and more
the use of drugs to a few of the better known, there is

150 EXPLOITATION OF PLANTS

loss as well as gain in this system, and the distinct revival
of interest in herb lore may well be productive of the
discovery of new and important drugs if associated with
wider knowledge and more scientific investigation.

In addition to the British Pharmacope@ia and the British
Pharmaceutical Codex, there exists an important com-
pendium of plants of established medicinal value in
the National Botanic Pharmacopeia, published by the
National Association of Medical Herbalists of Great
Britain.

The curious use of Drosera rotundifolia, the insec-
tivorous sundew, which is official in homeopathy for
pulmonary consumption, needs scientific investigation.
Unfortunately in this country the people’s knowledge
has been allowed to lapse more than on the Continent,
where “ simples ”’ are still culled and administered by
the housewife. This gives the more possibility, how-
ever, of interesting results accruing from studies in
relative folk-lore.

As the ancients are said to have watched animals,
so it behoves us to observe closely the habits of the
primitive peoples still left in the remote corners of the
earth. Exploratory and experimental research is still
more necessary where, as in Australia, there are few
natives, and those rapidly disappearing. We are un-
fortunately unable to believe, with certain herbalists of
the sixteenth century, that ‘‘ God has imprinted upon
the plants the very signature of their virtues,’”’ by some
cabalistic likeness to the part of the human body affected
thereby, but.everything goes to show that Nature usually
gives us the hint, if we do but sufficiently closely observe
her doings,

THE PLANT AS HEALER 151

In view of the series of alkaloids known to exist in
the Solanacee, it is not’surprising to find in a recent
American publication an account of the use of Datura
Metel as a narcotic by certain primitive Indian_tribes.

It would be of immense interest if evidence were
obtained of native use of the abundant droseras of
Australia, and in view of the application of Drosera
rotundifolia in Great Britain might well point to
the existence of unexplored medicinal principles in
this group destined to be of value in tuberculous
disease.

In the meantime there is waiting at our door the im-
provement and development of the important drug
plants known to us, and the even more limited, but very
practical, and urgent question of the production in
England of the necessary herbs to make good the inter-
ruption of the supply occasioned by the war. Though
more medicinal plants are grown in this country than is
usually realised, Mr. Evans (1) affirms that many more
could be introduced, as, for instance, Cascara Sagrada as
a hedge plant, while Podophyllum peltatum could be
reared in Norfolk or the New Forest. English henbane,
lavender and mint stand untouched by any rivalry. It
is a recognised fact that English henbane is the only
really satisfactory kind, and this is a plant of great
importance, as its use is not attended by the deleterious
gastric effects of opium. On the other hand, the open
tracts of country and well-organised system of gather-
ing and export gave the Central Powers a practical
monopoly of the herb trade prior to the war.

These matters should be considered together if the
industry is to be established, and Mr, A. D. Hall

152 EXPLOITATION OF PLANTS

(Development Commissioner and now Secretary of the
Board of Agriculture) classes (2) drug growing and
manufacture as a.subsidiary agricultural industry, which
it behoves us to try. As in other agricultural matters,
probable post bellum conditions must be considered,
since the comparative slowness of agricultural returns,
the moment of inertia, so to speak, in the operations
involved precludes a sudden volte face to meet new.
conditions. I place on one side the political aspects of
the situation, to dwell only upon the responsibility of
the grower, who must not rely on the special conditions
obtaining at the moment, but be prepared not only by
organisation, but by scientific development to face
renewed competition in the near future.

On the debit side of all accounts appears annually the
sum set aside for depreciation. I should like to see also
in such an industry as we are contemplating an annual
sum set on one side for appreciation, if I may so term it;
not only a sum “ to make good,” as we say, loss, but a
sum ‘‘ to make better,’’ bread upon the waters which,
maybe, will return a hundredfold. Now, it is obvious
that methods of improvement are so slow and expensive,
that one grower, or group of growers, can effect little;
but if small sums are pooled to support experiment,
as is done by the Cotton Spinners’ Association, much
might be effected.

What are the directions in which experiment might
work ¢

We have it on the authority of Mr. Holmes of the
Pharmaceutical Society of Great Britain that the cul-
tivation of medicinal plants is capable of improvement
under more systematic and scientific control, and, as

THE PLANT AS HEALER 153

a matter of fact, some experiments are now in progress
at Cambridge on the effect of different manures.

_ In America Bailey (3) records the increase of gluco-
sides in Phaseolus, Zea and Sorghum following upon the
increase of nitrate manure. Tannin is also affected by
manuring, none being found in Phaseolus, when chlorine
is absent, while it is well known that the highest tannin
yield is obtained from oaks grown on silicious soils.
Bailey remarks also on the influence of climate on
flavours—due to essential oils—as on other ingredients
of plants. :

An extreme instance of climatic control is furnished
by the hemp plant, Cannabis sativa. The Indian grown
plant alone is narcotic, with the result that it was at one
time regarded as a separate species, but there is no doubt
that the surprising difference between the supposed
distinct species C. Indica and the European Cannabis
sativa is climatic. The modern development in ecolo-
gical aspects of field work bids fair to help considerably
in the elucidation of problems of this kind, and the
analysis of climatic and edaphic factors paves the way
to that partial control of plant products to be desired
in the service of man. But there is also another means
to this end emerging as the result of modern experiments
‘on heredity. Thus Bailey’s account of the breeding
experiments with pumpkin and gourd, showing associa-
tion of the size of the former and bitter principle of the
latter, suggests that a similar but useful combination of
robustness and medicinal content might be effected by
the interbreeding of certain medicinal plants, and in
fact some progress along these lines has been effected
in connection with cinchona trees. -

154 EXPLOITATION OF PLANTS

Little has been done, however, as yet in the light of
the more exact possibilities of Mendelian breeding. It
is affirmed, however, that the biennial varieties of
Hyoscyamus niger are Mendelian in their behaviour,
so that pure strains can be isolated—a fact of great
importance to the drug trade.

Prof. Bayley Balfour writes: “‘ There is undoubtedly
room for heaps of work in the matter of drug plants,”
and Mr. Bateson informs me that there is some reason
to stippose that scent-bearing and non-scent-bearing
characters behave in a truly Mendelian manner.

These indications justify, nay, demand an output of
capital and labour commensurate with their significance,
in the sure hope of an ultimate reward, both scientific
and humanitarian.

REFERENCES
1. Royal Commission on Resources and Trade of the Dominions.
2. A. D. Hatt, Agriculture after the War. ~

3. L. H. Bartey, Plant Breeding, 1906.

4. FLUCKIGER and Hansury, A History of Drugs.

5. SouTHALL, Materia Medica.

6. A. B. TEETGEN, Profitable Herb Growing and Collecting.
7. A.R. Cusuny, Therapeutics.

CHAPTER X

PLANTS AS A SOURCE OF NATIONAL POWER—COAL !

By MARIE C. STOPES, D.Sc., Ph.D.
Lecturer in Paleobotany, Fellow University College, London

Man is not only a restless centre of energy himself,
he demands increasingly the dispersal and rearrangement
of the energy of the material world around him. Units
of energy, leashed, give man his power to build, to
grow and to destroy ; and of all stores of dormant energy,
coal is the most useful to him.

In the words of the Royal Commission on Coal (1905),
“Weare convinced that Coal is our only reliable source
of power, and that there is no real substitute ’’ for coal.
It is true that we were a powerful nation in Elizabeth’s
reign, and yet it is said that she prohibited the use
of coal in London when Parliament was sitting, lest
the health of the Knights of the Shires might suffer
during their residence in town. But that was before
the days of the hatching out of James Watt’s brood of
steam engines, which, like fiery dragons, demand more
and ever more energy to feed them. Yet we dare not
slay these dragons, as Samuel Butler told us to do in
his inimitable Erewhon, for in the world to-day other

1 Public Lecture delivered at University College, London, March 26,
IQI7-
155

156 EXPLOITATION OF PLANTS

nations have harnessed them, and before these nations
we should be helpless without our own energy-
transformers.

In a normal year, the forty millions or so of the
population of the United Kingdom use, or waste, some-
thing over 5,000,000,000,000,000 British thermal units
in coal alone. But of this array of units of energy in
coal which we destroy we have actually used but a frac-
tion, for we waste ten at least for every unit put to
useful -work.

From mighty waterfalls (if we had them) we might
get this number of units of mere energy, but that would
not be the equivalerat of the wasted coal, for from a
waterfall could be got none of the myriad other products
which make coal the most essential of raw materials.
Recent events have made us all realise how dependent
we are for our home comfort on the coal supply; but
some, perhaps, who were without coal, cherished them-
selves with gas, coke or electricity, without realising
that all three are the products of the manipulation of
coal. Without exaggeration, one may say that coal is
the very basis_of our civilisation, because not only our
home-life depends on it, but its use is essential for the
production of nearly every manufactured article : war-
ships, ploughs, or babies’ feeding-bottles, the cloth we
wear, the high explosives we use against the Germans,
all are either the direct products of coal or the result of
coal-stoked furnaces which drive machinery. Not only
is coal the foundation upon which the edifice of our
present civilisation is built, it is part of the superstruc-
ture. Several hundred thousand organic compounds
are obtained directly or indirectly from coal, the names

NATIONAL POWER AND COAL 157

of many of which, like carbolic acid, for instance, are
“household words’’; but most of them are known
by name only to the specialists who deal with them. |
Coal products in some form or other are used in
innumerable trades and manufactures. We swallow
coal products, wear coal products, scent ourselves with
coal products, nourish our flowers and crops with coal
products, destroy our enemies with coal products.

_ How much coal does it take to do these things, and
more, for us¢ As these last years have been abnormal,
T will go back some distance for actual figures : in 1903
in the United Kingdom we used approximately—

For our Railways . . . . . « + 13,000,000 tons of coal.
Bhi sis Factories + 8 6 6 4 6 + © 53,000,000 5, 54 54
gee cap IVES ar os a ah eB 9 B,OO0000. +540 35 “5;
» 9 Ironand Steel Industries . . 28,000,000 ,, ,, 5
3. 37 Gas Works: 4 2 «= « 4 % 19,000,000 .,, 5, -y,
x» », Domesticuses . . . . « 32,000,000 , 4, ,,

and, as we are a coal-producing nation, we exported very
much more than all that was used in our houses. I
need not remind you that our financial position as a
nation is largely influenced by our export trade, hence,
indirectly, coal is thus another source of power to us.

To illustrate how greatly our use of coal increases
with the years, a few comparative figures may be of
interest ; and these tables will also indicate the relative
changes of precedence held by the leading coal-producing
countries in these short periods of time.

In 1845 Production was— In 1865 Production was—
Great Britain . 31,500,000 tons Great Britain. 99,760,000 tons
Belgium . . 4,960,077 ,, Germany . . 28,330,000 ,,
U.S.A. . . . 4,400,000 ,,> USA. «+ + 24,790,000 5
France . . . 4,141,617 ,, France . .» 11,840,000 ,,

Belgium . . 11,840,000 ,,

158 EXPLOITATION OF PLANTS

In 1914 Production was—

US.A.. 6. 6. 6 6) 6) +) )=«513,525,477 tons
Great Britain . . . «. ~ 297,098,017 ,,
Germany . . . + «+ «+ 270,594,952 »,
France (1913) . . . «© + 45,108,544 4,
Belgium (1913) . . +. + 25,196,869 ,,

Germany is rapidly catching up, as can be seen from
these three tables, and she has huge reserves, the United
States already immensely exceeds us in thé quantity
she produces; but neither of these countries are part
of a widely scattered empire as we are. For the sake
of a truer comparison between the coal production of
the British Empire and these two countries, I give below
that of the various parts of our empire and of Germany
and the States for 1910. In that year production was—

By U.S.A. . . « ~ + 445,810,000 ons
» Great Britain . . . 264,500,000 ,,
» Germany . . . . 221,980,000 ,,
»» Canada mt een oe 13,010,000 ,,
» India . . . « « 12,090,000 ,,
» Australia . . . . 10,000,000 ,,
gy os Aftica a. 6 5,500,000 ,,
>» New Zealand . 2,230,000 ,,

Having thus reminded you of what coal means to us
in a practical sense, let us consider: What is Coal ?
A great variety of incomplete or inaccurate statements
about it are to be found in dictionaries, encyclopedias,
and textbooks, but I do not know of any published
definition which is entirely satisfactory. Hence,
recently, at the Society of Chemical Industries, I had
the temerity to define coal provisionally, and for want
of a better definition for the moment I will offer that.
“ Ordinary coal is a compact, stratified mass of dis-
membered ‘ mummified’ plants (which have decayed to

NATIONAL POWER AND COAL 159

varying degrees of completeness) free from all other
matter, save for the mineral veins, partings, etc., which
are local impurities,” as are the quartz veins in a nugget
of gold. Itis to be noted that unless the plant substance
is sufficiently free from other matter to be substantially
a deposit of plants alone, it is not a coal; but impure
coals may grade into oil shales and a variety of other
deposits. There are many varieties of coal which really
merit separate consideration, but though cannels,
anthracites and the others have their commercial im-
portance and scientific interest, for the purpose of this
lecture I shall generally mean by “ coal’? the most
important and most widely used ‘ bituminous” coal
of the household and factory.

I do not wish to mislead you into thinking that my
definition represents a universally accepted view of coal,
but I believe it will be the generally accepted view when
sufficient time shall have elapsed after the completion
of certain researches now in progress. At present
there is in the air a vague idea that coal is in some way
due to plants, but they are widely supposed to be
mineralised plants. Prof. Lebour in the recent British
Association discussion on coal said: “ Geologists regard
coal as a rock’’; and it is widely called a “‘ mineral,” a
“ rock,’”’ a “‘ stratified rock,” or other term, which con-
veys to ordinary people the suggestion that it is a stone
of some sort. In the older books black coal, such as
we use in this country, is always spoken of as “‘ stone
coal.’” On the other hand, some experts, influenced
still by Frémy, tend to-look on coal as he did, as
a structureless, hardened jelly. Shakespeare asked:
“‘What’s in a name? ”’ and I would answer, that it is

160 EXPLOITATION OF PLANTS

ra

the very mould of human thought, and in its name lies
the conception of a race about the thing it names.
Hence, I regret that coal is so universally called a
“ mineral.”

When I was a child of about eight or nine years old,
I first heard my parents speaking of a curious incident
of their honeymoon. They had gone into the Egyptian
desert, and at one place the little railway train had been
stoked with animal mummies for want of ordinary
fuel. My childish imagination had never been stirred
by the thought that coal could make an engine move,
but the idea that mummies could do so seemed like
some fairy tale of old Baghdad, and impressed me not
only with its faint aroma of horror, but with a vivid
revelation of the magic power of the steam within the
boilers.

And now my research into the structure of coal is
bringing me back this sense of magic, for it is becoming
clear to me that coal is mummies—the mummies of dis-
membered plants.

In general the remnants of extinct creatures of former
periods of the world’s history are spoken of as “‘ fossils,’’
or “ petrified remains ”’; indeed, the terms “‘ fossil,”
and “‘ petrifaction ”” are almost synonymous, for most
of the fossils are petrified, and the plant or animal
is represented by a simulacrum in stone. But in some
instances the very substance of the creature is preserved
from decay by natural chances, as were mummies by
man’s design. This is what happened when coal was
formed—the dismembered fragments of plants of all
sorts were preserved together, neither petrified nor
mineral-infiltered, but shut away from the air to form a

NATIONAL POWER AND COAL 161

stronghold against bacterial attack before it had made
too devastating a progress.

The coal which looks so black a lump in your hand,
is not black if it is cut in thin enough sections ; but it
is extremely difficult to cut such sections, because, as
the slice is being rubbed down to be made thin, it tends
to crack and split up. Without doubt many of the older,
and still prevalent, mistaken notions about coal are
due to the difficulties of section cutting. This art has
been greatly improved in the last few years by Lomax,
in this country, and Jeffrey and Thiessen in America, ©
so that the way is prepared for more satisfactory re-
searches into coal structure.

When a thin section is obtained it appears under the
microscope as a mottled mass, grading from. opaque
to transparent regions of deep coppery red to yellow.
The untrained eye finds it difficult to see any structure
in coal, save the most conspicuous and well preserved ;
and the most conspicuous things in most coal sections
are the spores, particularly the macrospores. These
originally spherical or egg-shaped bodies are generally
flattened, but often they appear to be not otherwise
affected, and their thick, uniform walls show up as
brilliant yellow or orange bands in the more opaque or
granular masses of the coal. The conspicuous appear-
ance of these spores, even in sections not otherwise
very good for microscopic examination, early attracted
attention to them, and probably partly accounts for the
extreme view of their importance in coal formation taken
by Huxley in his famous essay in the Contemporary
Review for 1870. Dawson, who knew infinitely more
about coal than did Huxley, answered him in the

M

-

162 EXPLOITATION OF PLANTS

following year, and maintained his (Dawson’s) original
thesis, that in the coals of Nova Scotia and New Bruns-
wick, at least, spores were relatively unimportant, but
that the barks of Sigillarias, and Calamites, and other
great forest trees of the Coal Measures were the principal
source of the bright layers. Since those days many
researches on coal have been published in many coun-
tries, yet it still remains woefully true, as Parkinson said
in 1804, that ‘‘ Among the humiliating proofs of our
limited powers of inquiry, there are few which are more
striking than that which is manifested by the ineffi-
ciency of our investigations relative to coal.”” Though
to Huxley’s question, ‘‘ Why does not our English coal
consist of stems and leaves to a much greater extent
than it does ¢’’ we can answer to-day that it does con-
sist of stems and leaves to a much greater extent than
he knew.

The vegetable origin of coal is indubitably true, and
whether you accept Frémy’s theory that coal is a
structureless plant jelly, Huxley’s view that it is chiefly
made of spores, or White and Thiessen’s view that it
“is chiefly composed of residue, consisting of the most
resistant components of plants, of which resins, resin
waxes, waxes, and higher fats, or the derivatives of the
compounds composing these are the most important,”
or my view that ordinary coal is preponderatingly com-
posed of variously preserved plant mummies—you will
all be agreed as to its vegetable origin.

Hence, recalling the vast practical uses of coal, we
see that for all these wonders we are indebted to plants.
We use, or waste, every year the energy and the products
which were stored in the plant bodies of long ago. So

NATIONAL POWER AND COAL 163

astonishing is the quantity of their substance in our Coal
Measures, that the idea has got about that the plants
or the atmosphere, or both, of those times, must have
been unique in their coal-forming power. And this
“view has been fostered by the natural configuration of
Western Europe. In this country our important com-
mercial coals are of Coal Measure (paleozoic) age,
and in Germany, Belgium and Northern France also
this is. true. In Germany, where more recent coals
are also valuable, they are all ‘lignites,’” or ‘‘ brown
coals,” and hence appear to support the view of the
exceptional black-coal forming conditions of the Coal
Measures.

Without going beyond our own empire we can dis-
cover how fallacious is this view; and true black coals
are to be found in almost every geological period in
some part of the world or other. For instance, the
assumption that Tertiary or Cretaceous coals are all
lignites or brown coal (and therefore of little value) is
disproved by the great coalfields of true bituminous
coal, and even anthracites in Western Canada. While
in Eastern Asia, one of the greatest storehouses of coals
in the world, vast deposits of true black coal are of this
geologically recent age.

Even where the Tertiary coals are still in the brown-
coal stage, they are of great commercial value if intelli-
gently utilised, and this the Germans, who have such
large stocks of brown coal, have been wise enough to
do. The brown coals also are mummified plant masses,
in most instances entirely comparable with black coals,
save that they contain more moisture and are less com-
pressed and consolidated. As wise old Goeppert

164 EXPLOITATION OF PLANTS

realised in 1861, the boundary made between black coal
and brown coal is often artificial and unscientific, and
the distinction is far clearer in textbooks than it is in
Nature.

Important coals are to be found in each geological
horizon in some part of the world; until we get right
back to the Upper Devonian, which is the oldest epoch
in which true coals occur.

If the leading divisions of geological time are arranged
vertically, a few of the more important coalfields of
corresponding age may be indicated beside them to
illustrate the above remarks.

Geological Epoch. A few of the areas with commercially
useful coal of corresponding age.

Tertiary . . . . Germany, Canada, U.S.A., Japan, Spitz-
bergen, New Zealand, etc.
Upper Cretaceous . . France, Servia, Canada, U.S.A., etc.

Lower Cretaceous. . Spain, Balkans, etc.
Jurassic. . . . «. Sweden, Caucasus, Portugal, China, etc.
Triassic. . . Virginia, U.S.A., Japan, Sweden, etc.

Permo-Carboniferous . India, New South Wales, etc.

Coal Measures. . . England, Scotland, France, Belgium, Ger-
many, Russia, U.S.A., Canada, China, etc.

L. Carboniferous . . Scotland, Russia, etc.

Upper Devonian . . [Bear Island (Arctic) : true coal, but of more
scientific than commercial value.]

This indicates that each of these geological epochs is,
in some part of the world, represented by local “* Coal
Measures.” Now we know from the palzontological
record, as well as from our theories of evolution, that the
organic life of the epochs was ever changing, trending
toward.genera and species liker and liker to those around
us to-day. Hence, as coals are found throughout all
these periods of time, we must either postulate the
special survival of ‘‘ coal-forming” plants, or accept

NATIONAL POWER AND COAL 165

the view that the plants of any geological age can make
coal. In my opinion there is potential coal in every —
plant, in an oak tree as in a Lepidodendron, in a goose-
grass as in a Sphenophyllum. In one of the greatest
coalfields of Japan, of Tertiary age, I have seen much
evidence that the woody trees of genera still living
contributed to the thick beds of true black coal; and,
to come nearer home, in Canada the great coalfields
of the West are rich in evidence that they were produced
from a mixed flora of “‘ modern ”’ type, mainly Gymno-
sperms and Dicotyledons.

Coal, in truth, is not the product of a particular kind
of plant, nor is it the product of particular parts of
plants ; it may be produced by any parts of any kind of
plant. But we are still ignorant of the extent to which
differences in quality and in contents may depend on
the differences in the parts of the plants producing
it. This carries us into a realm of work too technical
for present discussion.

To plants, then, we owe our coal, to coal our power,
to coal innumerable substances wrought into our com-
forts and our luxuries. Our demands for power and for
luxuries grow daily : does our source of these, our coal ¢
The answer, as is probably well known, is in the nega-
tive. As a result of the recent searchings of heart
caused by the war, it is also probably well known that
we have certainly a few hundreds, possibly a thousand
or two, years’ supply of coal. But long before we have
reached the limits of our reserves, coal will have become
so expensive and difficult to get that we shall have to
face the handicap of restriction of all those things coal
provides. It may be of interest to some to have before

166 EXPLOITATION OF PLANTS

them the estimated total reserves of coal of all kinds in
the world. They are—

Asia » oe « s+ « s 1,279,586,000,000 tons
America . . . « « + 5,105,528,000,000 ,,
Europe. . . . « + + ° 784,190,000,000 ,,
ICA as, has a? GANG re 9 ae 57,839,000,000__,,
Oceania . . . . . 170,410,000,000 ,,

Many suggestions for reform and economy of our use
of coal are before the public ; and I will not repeat them.
But it is of interest to know that the demands for Govern-
ment intervention in our handling of coal are neither
so novel nor so recent in origin as most believe. In
the course of my efforts to read all that has been
published on the aspects of coal research which interest
me, I came upon the work of J. Williams, published in
1789. The book is in the British Museum, and the
title page immaculate, else I should have thought I was
reading extracts from the current newspapers. In 1789
this prophetic man proclaimed : “ If our coals are really
not inexhaustible, the rapid and lavish consumption of
them calls aloud for the attention of the Legislature,
because the very existence of the metropolis depends
upon the continued abundance of this precious fossil
... and not only the metropolis ... but the most
fertile countries in the three kingdoms. . . . It is high
time to look into the real state of our collieries.” He
continues: ‘‘ The present rage for exporting coals to
other nations may aptly be compared to a careless spend-
thrift, who wastes all in his youth, and then heavily drags
on a wretched life to a miserable old age, and leaves
nothing for his heirs.” If this was said in 1789, what
can be said to-day ¢

NATIONAL POWER AND COAL 167

Williams recognised the difficulties and economic
dangers of restricting exports, and suggested that
Government encouragement should be given for the
development of coal resources in other parts, Cape
Breton, for instance.

But to-day it will not help the world as a whole to
waste coal outside as well as inside the United Kingdom ;-
other counsels must prevail. I will not repeat the
general suggestions for coal economy, much as I have
some of them—the use of powdered fuel, for instance—
at heart ; rather let me present an aspect of the subject
generally neglected.

The “ analyses ”’ of coal given by the chemist denote
merely the proportions of carbon, hydrogen, oxygen,
nitrogen and ash in the sample. Sometimes the amount
of sulphur is determined. Thus a typical coal analysis
is as follows—

(oF H. 0. N. s. Ash.
7481 % 498% 4:99% 122% 0:96% 3:04% of 100 parts of coal.

What indication is there here of the molecular com-
plexity of the mummied plants of which it is composed ¢
What indication of the complexity which, out of 100 lb.
of coal, yielded 23 02. of benzol, less of toluol, and + oz.
of Perkin’s mauve?’ There is obviously no indication
in such analyses of the true combinations of the elements
into chemical compounds, nor of the type of compounds
into which they may be converted. Mauve and toluol
and countless other products obtained from coal are
valuable and costly, but I know of no rational efforts to
attempt to discover what it is in the coal which is their

168 EXPLOITATION OF PLANTS

source. Yet, were the source of each such substance
discovered, there would open up a vista of potential
economies, and we might then use coal only to get from
it the things not obtainable in other ways. To-day
Americans are finding it pays to grow sissal (Agave
rigida) for the production of alcohol from its leaves,
and the necessary machinery is run by the dried and
caked fragments of the same leaves used as fuel. Both
in German East Africa and British East Africa sissal
covers hundreds of thousands of acres, and, it is said,
the profit in exploiting it thus amounts to 20 per cent.
at least. But this is merely one illustration of illimit-
able possibilities. The French, sadly out of coal by
the war, have formed a committee to look into practical
gas manufacture from substitutes for coal. To what
do they turn to supplement the power they owe to coal ?
Again to plants. In a recently published report they
found that even the squeezed pulp residues from olives
gave not only a gas with a high illuminating power,
but a charcoal which, with tar, makes good briquets for
fuel, From a péculiarly resinous material, the strainings
of the resin tapped from pine trees, they got a gas of
specially high illuminating power.

Though at present there is no attempt to correlate
these products with the details of botanical structure
of the plants thus used or usable, such research cries out
to be done; some day it will be done.

When we thoroughly know our coals, their contents
and the sources of their contents, we shall have gone a
long way toward overcoming the dangers of lack or
restriction of coal. I see, as no impossible dream, not
only the wise utilisation of the fuel we have, but the

NATIONAL POWER AND COAL 169

artificial production of particular kinds of coal from
particular types of plants to supply special substances

. We may from time to time require as our civilisation
advances.

In 1833 our countrymen led the way in microscopic
examination of coal. For long we led in the production
of coal; we have lost that lead. Ever since coal was a
marketable commodity we have led the world’s export
trade in it—now, owing to the disposal of the stores of
coal by Nature, we see that we cannot for ever maintain
that lead. Hence, now, let our inspiration be to lead
in real understanding of coal and the plants which
formed it, and by our understanding master the coal
problem.

But that means Scientific Research, and yet again
Research.

A Few REFERENCES TO THE LITERATURE ON COAL

The general reader will probably find most interest in ‘ The British
Coal Trade,” by H.S. Jevons, 1915. Pp. xii, 876, 23 text figs. and
maps. London.

From the vast scientific literature on coal the following are selected
as of outstanding interest and importance.

The chapters on coal in “ Acadian Geology,” by J. W. Dawson, Ed. 2,
1868. Pp. xxvi, 694, 231 text figs. London.

“ The Geology of Coal and Coal Mining,” by W. GriBson, 1914. Pp.
viii, 341, 37 figs. London. :

“The Coal Resources of the World: An Inquiry made upon the
Initiative of the Executive Committee of the rath. International
Geological Congress, Canada, 1913,” 3 vols. and atlas. Toronto,

“Formation of Coal Beds,” by J. J. STEvENson. Proc. Amer. Phil. Soc.,
vol. 1. (1911) pp. 1-116; 519-643: vol. li. (1912) pp. 423-553:
vol. lii. (1913) pp. 31-162. Lancaster, U.S.A. (Republished in

Iso. -_ ; :
ee Pie Decne: Ceckegy of the Netherlands and Adjacent Regions, with

170 EXPLOITATION OF PLANTS

special references to the latest borings in the Netherlands, Belgium
and Westphalia,” by W. A. J. M. VAN WATERSHOOT VAN DER
GracuT and W. Joncmans, 1909. Pp: viii, 437, 10 pls., 14 figs.
The Hague.

“ The Origin of Coal: with a Chapter on the Formation of Peat,’”’ by
D. Wuite and R. TuIEssEN, 1913. Bureau of Mines Buil. 38.
Pp. x, 304, 54 pls. Washington.

PRINTED IN GreaT Britain By RicHaRD Cray & Sons, LimitTep,
BRUNSWICK ST., STAMFORD ST., S-E. 1, AND BUNGAY, SUFFOLK.

THE IMPERIAL STUDIES SERIES

THE OLD EMPIRE AND
THE NEW

THE RHODES LECTURES DELIVERED AT
UNIVERSITY COLLEGE, UNIVERSITY OF
LONDON, IN THE SPRING OF 1917, BY

ARTHUR PERGCIVAL NEW DOM

M.A., D.LiT., B.Sc.
Lecturer in Colonial History, University of London

WITH AN INTRODUCTION BY
DLR. CHARLES: LUCAS, K,C.NLG.

144 pages. Cloth, Crown 8vo, 2s. 6d. net

CONTENTS

GENERAL INTRODUCTION
I. THE CONTINUITY OF IMPERIAL HISTORY
Il. THE ADMINISTRATION OF THE EMPIRE

III. SEA POWER AND THE DEFENCE OF THE
EMPIRE

IV. IMPERIAL TRADE

THE DEPENDENT EMPIRE AND THE NATIVE
RACES

VI. STEPS TOWARDS IMPERIAL UNITY
This volume is designed to introduce the Imperial Studies
Series by insisting on the fact that in considering matters of

Empire it is necessary for the Student to base his work upon
history, tradition and accomplished fact.

J. M. DENT & SONS, LTD.
ALDINE HOUSE, BEDFORD STREET, W.C. 2

THE IMPERIAL STUDIES SERIES

THE STAPLE TRADES
OF THE EMPIRE

A SERIES OF LECTURES DELIVERED AT THE
LONDON SCHOOL OF ECONOMICS DURING
THE SPRING OF 10917

EDITED BY
ARTHUR PERCIVAL NEWTON

M.A., D.Lit., B.Sc.

CONTENTS

INTRODUCTION. By the GENERAL EDITOR

OILS AND FATS. By the Right Hon. ARTHUR STEEL-
MAITLAND, M.P.

SUGAR. By C. SANDBACH PARKER, M.A.
WHEAT. By HuGH R. RATHBONE, M.A.

METALS AS THE BASE OF IMPERIAL STRENGTH.
By OcTavius CHARLES BEALE

THE IMPORTANCE OF IMPERIAL WOOL. By E. P.
HITCHCOCK, M.A.

THE COTTON RESOURCES OF THE BRITISH EMPIRE.
By Professor JOHN A. TODD

WITH MAPS AND EXPLANATORY DIAGRAMS

Each industry is dealt with by some leading expert who can
speak with authority concerning it. This volume is complementary
to “The Exploitation of Plants.”

J; Mt DENT -& SONS, LID:
ALDINE HOUSE, BEDFORD STREET, W.C. 2