E F Wright.

Plant disease and its relation to animal life online

. (page 1 of 8)
Online LibraryE F WrightPlant disease and its relation to animal life → online text (page 1 of 8)
Font size
QR-code for this ebook


IRLF




B 3 flT3




MAIN UBRARY AGRIC. OEFT,



PLANT DISEASE



PLANT DISEASE

AND ITS RELATION TO
ANIMAL LIFE



BY

E. F. WRIGHT
ti

AUTHOR OF "TUBERCULOSIS," "RINDERPEST AND HOW IT MAY

PROPAGATED," " WATER IN SOUTH AFRICA," ETC.




LONDON

SWAN SONNENSCHEIN & CO LTD

PATERNOSTER SQUARE
1903



BIOLOGY
LIBRARY



MAIN ?



1



PREFACE

IN an address to the North British Branch
of the Pharmaceutical Society, by J. Arthur
Thompson, Professor of Natural History in
the University of Aberdeen, delivered in 1901,
the following passage occurs :

" Even in my few illustrations I have prob-
ably made mistakes by touching subjects which
are beyond my field of work, but to pounce
upon these is to ignore the whole aim of my
address, which is to suggest that the various
departments of science yours and mine and
that of others are all correlated. It is not
solely by the aloofness of specialism, but by
mutual interest, and active co-operation as
well, that we make progress in understanding
the one problem which, in some form or other,
is before us all The Order of Nature."

In the following pages, I may perhaps to

V

M167495



VI PREFACE

some appear to be too discursive, but I base my
defence on the complexity of the subject with
which I deal, and on the plea that it does
in effect touch upon such varying depart-
ments of science as chemistry, pathology,
physiology, and their practical branches. To
understand the theory that I here advance,
a recognition of the claim put forward by
Professor Thompson for a sympathetic and
unbiassed inquiry into the Order of Nature is
the first necessity.

E. F. W.



CONTENTS

CHAP. PAGE

I INTRODUCTION i

II CHLOROPHYLL AND HAEMOGLOBIN . . 18

III VARIATION 39

IV IMMUNITY OXYGEN AND OZONE . , 59

V EFFECT OF FOOD ON ANIMALS IN CON-
NEXION WITH DISEASE AND HEALTH
HEARTWATER SOUTH AFRICAN

HORSE-SlCKNESS EATING RAILWAY

IRON FLUKE TUBERCULOSIS . -75

VI HUMAN DISEASE CANCER LEPROSY

AND FOOD CONSUMPTION . . .103

VII AGRICULTURE HUMUS RUST IN WHEAT
SUGAR CANE OXIDE OF IRON AND
AMMONIA BACTERIA OR FUNGI
NITROGEN AND FATS FRUIT TREES
AND CHLOROSIS WEEDS, INSECTS
AND MANURES 118



CHAPTER I

INTRODUCTION

IT is commonly recognized that what is known
as chlorophyll is an essential constituent of
healthy plant life, and its absence, or presence
in insufficient quantity, is the cause of chlorosis,
which is one of the most formidable diseases
to which plants are liable. This chlorotic con-
dition is due to an absence of iron, as without
iron chlorophyll cannot be formed (see Ency-
clopaedia Britannica, vol. xix., p. 52), and is
often successfully treated by washing with a
weak solution of sulphate of iron. Now what
chlorophyll is to the plant, haemoglobin is to
the animal, the one being a red modification of
the other, as I shall show in a later chapter,
and Macallum holds (see Colour in Nature, by
Marion J. Newbigin, D.Sc.) that chlorosis
in plants and animals is due to the same cause,
a deficiency of iron. It follows from this that
herbivorous animals eating chlorotic food,

B



PLANT DISEASE



must necessarily fail to assimilate the requisite
quantity of iron, and will consequently have a
tendency to become anaemic, a condition as
formidable to health in the animal as is chlorosis
in the plant, as is recognized by various authori-
ties. A brief survey of the construction and
functions of the haemoglobin will make this
clear.

In Animal Physiology, p. 119, W.. S. Fur-
neaux says

" The colour of the blood is due to the pres-
ence of a nitrogenous substance, called haemo-
globin, in the red corpuscles. This substance
contains a considerable proportion of iron
oxide."

Again, in the Encyclopaedia Britannica,
article " Iron, Therapeutic Uses of," vol. xiii.
P. 359 we read

"If the haemoglobin of the blood fall below
a certain standard, the supply of oxygen
necessary to healthy tissue changes in brain,
nerve, muscle, etc., becomes too limited, and
the changes will be imperfectly performed,
hence defective vitality general or local."



AND ITS RELATION TO ANIMAL LIFE 3

Again

" In the lungs, the corpuscles through their
haemoglobin take up oxygen which they carry
to all parts of the body. But in the presence
of the vital processes of disintegration and
repair constantly going on in the tissues, the
corpuscles yield up the oxygen they have
brought and supply an element necessary
for these processes."

Therefore in an anaemic blood there cannot
be a sufficiency of oxygen taken up.

" Having got rid of the oxygen the haemo-
globin then unites with the carbonic acid pro-
duced by tissue disintegration, and the cor-
puscles thus re-laden carry their burden back
to the lungs, and discharge there the carbonic
acid " (Encyclopaedia Britannica, vol. xiii.
P- 359)-

Thus in anaemic blood, which can be un-
doubtedly produced by anaemic food, there
would not be a proper discharge of carbonic
debris.

This in my opinion constitutes the certain



PLANT DISEASE



group of symptoms, " which," says Rind-
fleisch, " recur with the uniformity of a type
in the most various diseases, depending as they
do upon one constant factor " (Encyclopaedia
Britannica, under " Pathology," vol. xviii.
p. 361).

Now if we return for a moment to chlorophyll,
we find another factor of great importance,
namely, that " In green plants it is only those
cells which contain chlorophyll that can absorb
carbon dioxide, and this only under the influence
of light, a sufficiently high temperature and a
supply of iron " (Encyclopaedia Britannica,
vol. xix. pp. 48 and 52).

Hence green plants deficient in chlorophyll
will be deficient in carbon dioxide ; in other
words, chlorotic plants are wanting in carbon
as well as in iron, because all carbon compounds,
whether in plants or animals, are derived
directly or indirectly from the organs contain-
ing chlorophyll.

Another important feature which, though
not fully recognized to-day, will, I think, be in
the near future, and on which I give some



AND ITS RELATION TO ANIMAL LIFE 5

evidence further on, is that iron is the means of
fixing the ammonia of the air in the soil to
form nitrates. In any case, I am sure there is
a fixed law by which the ammonia of the air
is fixed in the soil to form nitrates, just as
chlorophyll is the medium by which carbon
dioxide is fixed in the plant.

This is important, as the loss of carbon and
nitrogen can only be replaced by the use of
organic food substances, and cannot be supplied
from the air as oxygen can with the assistance of
a normal haemoglobin.

It is of the utmost importance that the loss
of carbon and nitrogen should be made good,
where they are wanting in chlorotic food, seeing
that carbon enters into the composition of all
the organic substances such as the carbohy-
drates, hydrocarbons, proteids, etc. (Encyclo-
paedia Britannica, vol. xix. p. 48).

We see, then, that chlorotic food does not
imply simply a deficiency in iron, but also a
deficiency in carbon, which means that chlorotic
food is wanting in sugars, fats, proteids, etc.,
and as the animal can only take in carbon by
means of food substances, it also means that



PLANT DISEASE



animals eating chlorotic food must be deficient
in sugar, fats and proteids.

Max Verworn, General Physiology, p. 158,
says

" The plant must construct the highly com-
plex proteid molecule out of the simplest
inorganic compounds, carbonic acid, water,
salts and oxygen, while the animal obtains
already formed the proteid food without which
it cannot live."

But the proteids are only taken into the
animal economy by means of the foods eaten.
It follows therefore that if such foods be either
chlorotic vegetable foods, or animal foods
derived from animals fed upon chlorotic
vegetable food, the individual so fed must be
deficient in these necessary proteids.

Chlorophyll, which is before every one in the
form of the green colouring matter of all forms
of vegetation, from the leaf of the oak to the
parsley leaf, is not of one constant standard.
" Iron is absolutely essential to the existence of
this compound, as chlorophyll cannot be formed



AND ITS RELATION TO ANIMAL LIFE



without the aid of iron " (Encyclopaedia
Britannica, vol. xix. p. 52).

Yet there are many soils quite wanting in
iron, and in the history of agriculture you never
read of manuring with iron, excepting possibly
in the case of some experimental plots, although
some iron has been used of late years in the form
of basic slag, which contains about 18% of iron,
with beneficial results, as proved by experiments
carried out by Dr. Somerville, especially in
the case of stock grazing on pastures so
manured.

Unfortunately, much vegetation is deficient
in iron, and consequently chlorotic, and it
would seem simpler instead of washing with
sulphate of iron, as is now occasionally done,
to have recourse to manuring the ground with
iron, when the plant would in due course take
up all it required for healthy growth.

The importance of this question of chloro-
phyll is so great that it may be as well to state
once more the facts of the case.

Chlorophyll is never formed in the absence
of iron. Only those cells in the plant that
contain chlorophyll are capable of absorbing



8 PLANT DISEASE



carbon dioxide, and unless this is absorbed,
the necessary proteids are not formed.

Animals, therefore, fed upon chlorotic food
cannot absorb the chemical constituents neces-
sary for health.

In a later chapter I propose to go more fully
into the formation of the starch, sugars, fats,
proteids, and protoplasm formed from the
carbon dioxide taken up through the agency
of the chlorophyll and to show that it is im-
possible for a chlorotic food to be as rich in
these proteids, etc., as vegetable food which
contains a sufficient percentage of iron, and
consequently of chlorophyll.

Another point to be considered in relation
to the haemoglobin is the important part it
plays in the absorption of oxygen into the
system. In the Encyclopaedia Britannica, vol.
xiii. p. 359, we read

" Each corpuscle consists of a stroma, per-
meated by a red fluid, haemoglobin, which
has the remarkable property of readily com-
bining with either oxgyen or carbonic acid,
but so loosely that under slightly altered



AND ITS RELATION TO ANIMAL LIFE 9

conditions these gases are readily separated
from it."

The haemoglobin, having such an affinity for
oxygen, and oxygen playing such an important
part in animal life, it is evidently of vital im-
portance that the animal should have the
maximum percentage of haemoglobin in the
blood, yet there is ample evidence to show
that there is great variation in the percentage
of this proteid substance in the blood brought
about by the varying amount of chlorophyll
matter present in the food.

In the Introduction to his Human Physio-
ology, pp. 37-38, Augustus D. Waller, M.D.,
F.R.S., states that in Disease the proportion of
haemoglobin in the blood often falls from
12% to i or 2%.

It is also well known that the red corpuscles
should be so numerous in the blood as to make
it a thickish liquid, but the proportion varies
considerably, as proved by analysis, as it is
entirely dependent on the kind and amount of
food eaten.

Having recognized the fact that there is a
considerable variation in the percentage of



10 PLANT DISEASE



haemoglobin in the blood, we must also admit
that there must be a corresponding variation
in the quantity of oxygen taken into the
system, and carbonic debris discharged, these
being the special functions of the haemo-
globin.

It is obvious, therefore, that an animal having
a normal or rich haemoglobin will absorb much
more oxygen into the system and discharge
much more carbonic debris than will an anaemic
animal.

And the extent to which the non-performance
of these vital functions may extend, is measured
by the fact above noticed, that it is possible
for the proportion of haemoglobin in the blood
to fall to one- twelfth of the normal.

Another important point in connexion with
a defective haemoglobin is that

" In breathing, nearly equal volumes of
carbonic acid are lost and oxygen gained.
Small quantities of other gases are given off
from the lungs, including organic matter,
which is exceedingly capable of putrefying, and
which is no doubt highly injurious and the
cause of much ill-health and of many diseases



AND ITS RELATION TO ANIMAL LIFE II



where the products of breathing have been
allowed to accumulate "

It is clear from the above that anaemia is
the cause of, or at least a predisposing factor
in, many diseases, and it is no doubt the con-
stant factor in various diseases to which Rind-
fleisch refers in the passage quoted above.

It being once admitted that the percentage of
oxygen absorbed into the system varies in
about the same ratio as the percentage of
haemoglobin in the blood, it becomes of interest
to see how oxygen effects pathogenic bacteria.

Encyclopaedia Britannica, vol. xxi. p. 400,
under " Schizomycetes "

" The investigations of Cohen, Pasteur,
Kock and others leave no doubt that many
bacteria are sensibly affected by the media
in which they are cultivated ; not only are the
forms modified, but also the physiological
activity varies in degree and even in kind.
The lung tissues of a healthy animal exert
actions which are antagonistic to those of the
parasite invader, and it is now generally
admitted that the mere admission of bacteria



12 PLANT DISEASE

into an animal does not necessarily cause disease.
Were it otherwise it is difficult to see how the
higher organisms could escape at all. Some-
thing must therefore be placed to the action of
the tissues of the host which, when healthy,
can ' resist ' the attempts of bacteria to settle,
grow, and multiply with fatal effect."

" Pasteur has shown that anthrax bacillus
cultivated in chicken broth, with plenty of
oxygen, and at a temperature of 42-436. lost its
virulence after a few generations, and ceased
to kill even a mouse. This has been con-
firmed by others " (see Encyclopaedia Britan-
nica, vol. xxi. p. 400).

In tuberculosis again, it is universally recog-
nized that oxygen is very beneficial, but the
fact that thousands of cattle living in the open
air suffer from it shows that it is not sufficient
that the oxygen should enter the lungs, but
that it is necessary that it should be absorbed
into the system, which can only be accomplished
by the action of a normal haemoglobin.

It is clear from the above that in certain
diseases at any rate, and as I think in most, the
animal having a normal haemoglobin is more



AND ITS RELATION TO ANIMAL LIFE 13

likely to be immune than one whose blood is
defective. In other words, if my contention is
correct, the susceptibility to certain bacterial
diseases is directly traceable to the use of
chlorotic food.

I shall develop this point at greater length,
and with reference to other bacterial diseases,
in later chapters, but it is sufficient for my
purpose here to have shown a direct connexion
between the bacillus and the chlorotic vege-
table.

The variation in the supply of oxygen is an
important factor in health per se, but it
acquires additional importance from the fact
that the discharge of carbonic refuse varies
with it pari passu.

The variation in the discharge of carbonic
debris derives its importance from the well-
known fact that carbonic debris is a food
for all pathogenic bacteria.

Hence, if we assume that in normal animal
life, that is in every case where there is a nor-
mal haemoglobin, all this debris is discharged,
it is an easy deduction that the undischarged
debris will increase as the haemoglobin de-
generates from the normal until the maximum



14 PLANT DISEASE

quantity of debris is retained in the system
of an animal suffering from acute anaemia.

It follows that the food of these bacteria
increases as the blood degenerates, and it is
clear that they will increase more rapidly
in those animals where the conditions are
favourable to their growth, than in those where
there is but a scanty supply of the food on
which they thrive. To this may be attributed
the variation in the virulence with which a
given disease attacks different animals, some
being by their physical condition a more fer-
tile soil than others for the propagation of the
pathogenic bacteria.

We may take as an illustration tuberculosis,
where some cases linger on for seven or eight
years and others die in as many weeks.

The greater the quantity of oxygen and the
less the quantity of debris in any individual,
the greater the immunity, while the converse
condition provides us with the more acute
forms of the disease.

But variation in these two factors does not
cover the entire ground in relation to immunity
or susceptibility in disease, for it is recognized
that proteids are fatal to pathogenic bacteria.



AND ITS RELATION TO ANIMAL LIFE 15

In Epidemics, Plagues and Fevers: their
Cause and Prevention, page 395, the Hon.
Rollo Russell says : " Dr. Buchner ascribes
immunity to proteid substances. Wild rats
fed on plain bread for about six weeks, suc-
cumbed to anthrax with which they were
inoculated, others fed on flesh did not take it,
and their spleens were found to contain an
abundance of the proteids."

Proteids, as stated above, are carbon com-
pounds which must be taken in by the animal
through the medium of food (General Physiology,
by Max Verworn, p. 158).

I have shown that the carbon of the plant is
governed by the chlorophyll, that the chloro-
phyll depends upon the iron, and that chlorotic
plants must contain less carbon compounds
than plants containing the maximum of iron
and consequently of chlorophyll, from which
it follows that a chlorotic plant will contain
less proteids than a plant containing the
maximum quantity of iron.

I have also shown that a normal food con-
taining a normal chlorophyll is a food which
will enable the animal to take up the maximum



l6 PLANT DISEASE

quantity of oxygen and to give off the maximum
quantity of carbonic debris, or food for patho-
genic bacteria, at the same time storing up in
the system the maximum percentage of pro-
teids. Such an animal must be more immune
than one with a deficient haemoglobin, where
oxygen and iron are deficient and carbonic
debris in excess.

In other words, the condition of immunity
will vary directly with the assimilation into the
system of normal food, and the degree of im-
munity will vary inversely with the amount of
chlorotic food consumed.

In a later chapter I shall go more fully into
the variations in the quality of given food
products, as shown by chemical analysis, and
hope to make it clear that to these variations
are due in many cases the liability to contract
disease and the lack of power to resist its
effects which cause so many premature deaths.

I venture to think, however, that I have said
enough to indicate the intimate relations ex-
isting between the animal and vegetable king-
doms, and to show that variations in the
vegetable world must produce variations in the
animal world, for which it provides food, and



AND ITS RELATION TO ANIMAL LIFE 17

that these variations or deficiencies are in the
main the predisposing cause in many diseases.
In the following pages I shall try to show
in a more or less detailed way how the quality
of the food is governed by the mineral con-
stituents present in or absent from the soil, how
the variations in plant food affect the immunity
or otherwise of the animal living on it, and
how these variations, either directly or through
the animal, affect man.



l8 PLANT DISEASE



CHAPTER II

CHLOROPHYLL AND HAEMOGLOBIN

NATURALLY normal blood must contain the
constituents of the whole body, as it is by
this means that the wear and tear of the body
is made good. For instance, the blood must
convey to the nails, hair, teeth, etc., the con-
stituents that go to build them up, and if it
is wanting in these constituents, we see the
teeth decaying, the hair falling out for want
of nourishment, the nails becoming thin and
weak like those of consumptives. Beyond the
constituents that go to build up the parts
there is the constituent which may be said to
be the very essence of animal life, namely,
haemoglobin. The functions of this con-
stituent of the blood are so all-pervading that
one can scarcely go too fully into the subject.
In the first place, it is admitted that arterial
blood, that is, the blood as it leaves the lungs,



AND ITS RELATION TO ANIMAL LIFE IQ

should be of a bright red colour when drawn
from the animal ; this blood clots quickly, being
of a uniform bright red right through the clot.

Now, if the blood were always of one con-
stant and normal colour, we should not hear
of many diseases ; but, unfortunately for the
animal world, there is very great variation in
the colour of the blood, an indication of
variation in its chemical composition.

In the large number of animals that I have
examined in South Africa the blood has more
often than not been of a much darker or
lighter colour than normal blood, when taken
in a similar way in each case, namely, from the
throat ; yet these animals were not showing
any signs of disease, and to the ordinary eye
were in normal health.

In many cases they had a very dark blood
only partially coaguable, proving there is
considerable variation in the quality of the
blood of ordinary animals, which is easily
explained and to be expected when one recog-
nizes the great variation there is in the quality
of the food eaten.

I have also noticed that whatever the
disease from which an animal was suffering,



20 PLANT DISEASE



the blood was always abnormal, either being
much darker or lighter than normal blood,
and in every case more or less non-coaguable.
In some cases of disease the blood has been so
thin as to run into the soil like water, which a
normal bright red blood could not do, as it
would coagulate on the surface. Such normal
blood contains a given percentage of nitrogen,
iron, phosphoric acid and potash, while the
blood of animals suffering from the class of
diseases known as fevers is always more or less
deficient in these constituents ; and it will be
found that the more virulent the disease, the
greater the deficiency.

It can be taken as an axiom that in all
fevers the active agent is a bacterium, which
is another name for one of the class of plants
known as fungi. It is thought by many that
it is the fungus that causes the chemical de-
ficiency, while others say there must be a
deficiency before the fungus can start its
growth. I shall try to show that the first
position is untenable. Some say that while
the bacteria could not consume the iron, they
might act on the blood chemically, so that the
iron would escape from the system.



AND ITS RELATION TO ANIMAL LIFE 21

This suggestion seems to be an impossi-
bility, brought forward to support a bad case,
because it has been proved over and over
again that iron is fatal to all fungi, conse-
quently it is unreasonable to suggest that
bacteria would attack a perfectly healthy
animal, and destroy the blood containing a
constituent which was a poison to them.

Secondly, if bacteria could attack all alike,
the natural conclusion would be that it would
not be long before these fungi would have
destroyed all higher forms of life off the face
of the earth.

That such is not the case, however, is proved
by the fact that the majority of the doctors
and nurses in consumptive hospitals always
remain immune to this disease.

Further, it has been proved that where
animals can obtain iron, they are much more
immune to bacterial disease than in places
where iron is wanting, from which we can only
conclude that the presence of iron, in the blood
enables animal life to withstand the attacks
of these bacteria, and as a corollary that the
bacteria do not produce the deficiency, a con-
clusion which is further confirmed by the fact



22 PLANT DISEASE

that bacteria can only live on foods that
correspond more or less with their own chemi-
cal composition.

Another factor is that proteids are fatal to
bacteria, and the fact that a normal haemo-
globin, which is of the nature of a proteid, is a
poison to these, explains why these fungi are
never found in a normal blood, for the all-
powerful reason that they could not live
in it.

This reduces the whole question again to
the fact that a normal haemoglobin, through
its various functions, which I have explained


1 3 4 5 6 7 8

Online LibraryE F WrightPlant disease and its relation to animal life → online text (page 1 of 8)