132 THE PROTEIN ELEMENT IN NUTRITION

of experiment by summing up the objections put forward to them,
and to any general adoption of dietaries containing the low level
of protein he advocates :

1. The method of basing the protein requirements of the body
on the average amount of nitrogen eliminated in the urine gives
too low a result for the protein metabolism per kilo of body
weight.

2. The very great variations recorded for the digestibility and
absorption of protein from identical diets for the individual
members of his second group — men of the hospital corps — can
either be explained on the basis of malnutrition of the intestinal
epithelium, the result of a diet poor in protein, or by failure of
the men to collect all the faeces passed each day, so that the
total amount included in the analyses was too low. For several
reasons we believe the latter to be the more likely explanation.
If this should be the explanation, it must throw a certain amount
of doubt on the collection of the daily urine for the five months
during which this experiment was carried out. Any loss of urine
would mean a seemingly lower level of nitrogenous metabolism
than was actually the case. It is well known how difficult it is
to save all the excretions, except where the most rigid precautions
are taken. In the work in India we found it absolutely necessary
to confine prisoners under observation to solitary cells, in order
to insure the complete collection of the urine and fasces. This
criticism would not apply to Chittenden's first and third groups
of subjects, who were educated men, and who would fully under-
stand the importance of saving the excreta in full.

3. Whilst one feels bound to accept the figures stated for the
daily intake of nitrogen in the dietaries published throughout
Chittenden's book, at the same time one cannot help feeling that
they would have been much more satisfactory if the nitrogen of
those dietaries had been computed from analyses of the dry
food materials used, before being cooked, instead of being esti-
mated by means of factors for the percentage of nitrogen in
cooked food. The percentage of moisture in any cooked food
may vary very considerably from day to day : this would be
specially marked with the more or less vegetarian types of diet
Chittenden was compelled to have recourse to in order to keep
down the protein content.

Apart from these technical objections which could be easily
overcome, there has been considerable mass of criticism levelled

CONCERNING LOW PROTEIN DIETARIES 133

at Chittenden's results, and the more remote effects of dietaries
low in protein. Hutchison* summarizes some of these, and
Crichton-Brownef discusses many others in detail :

1. While a low standard of protein intake may be adopted
with apparent impunity for considerable periods, it does not
follow that it can safely be pursued indefinitely. Excess of
protein is regarded as a margin of safety in increasing the general
tone of the system and the resistance to disease. Just as chronic
excesses in diet are slow in exacting their penalties, so a sub-
liminal diet may also be tardy in manifesting its untoward effects .

It is generally recognized that abrupt changes in the daily
food are very liable to produce gastro-intestinal trouble and
failure in health. It is quite possible that radical changes, even
when gradually introduced, may have ill-effects of an insidious
nature long before there is any obvious breakdown in health.

2. Existence at the lower limits of protein metabolism un-
doubtedly results in a wasting of the nitrogenous tissues and
fluids of the body during every special call or demand for increased
effort. This disintegrated tissue may take weeks to replace, and
thus convalescence from illness may be prolonged and recovery
rendered incomplete.

3. The effects of a diminished protein intake on the race is of
far greater importance than on the individual. The experiences
gained in India are specially interesting from this point of view,
and will be fully discussed presently. Suffice it at present to
say, that those people whose dietary affords a low level of protein
metabolism are, so far as our knowledge goes, of poor physique,
wanting in stamina, and lacking in the manly quantities that are
essential in commanding and maintaining the respect of the more
virile races.

4. Chittenden's claim, that the elimination of crystalline
nitrogenous bodies through the kidneys places upon these organs
an unnecessary burden, which is liable to endanger their integrity,
and possibly result in serious injury, in so far as it applies to the
ordinary accepted standard, cannot be substantiated, and is
opposed to universal experience.

Many other points might be raised, some of which we shall
discuss in detail later. One very important subject is the bearing
of a low protein dietary on the susceptibility to disease. We have

* Hutchison, " Food and the Principles of Dietetics," p. 24.
t Sir J. Crichton-Browne, " Parsimony in Nutrition," 1909

THE PROTEIN ELEMENT IN
NUTRITION

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THE PROTEIN ELEMENT
IN NUTRITION

BY

MAJOR D. McCAY,

M.B., B.Ch., B.A.O., M.R.C.P., I.M.S.

PROFESSOR OF PHYSIOLOGY, MEDICAL COLLEGE, CALCUTTA

ILLUSTRATED

LONDON

EDWARD ARNOLD

NEW YORK : LONGMANS, GREEN & CO

1912

[All rights reserved}

••

GENERAL EDITORS' PREFACE

THE Editors hope to issue in this series of International Medical
Monographs contributions to the domain of the Medical Sciences
on subjects of immediate interest, made by first-hand authorities
who have been engaged in extending the confines of knowledge.
Readers who seek to follow the rapid progress made in some
new phase of investigation will find herein accurate information
acquired from the consultation of the leading authorities of
Europe and America, and illuminated by the researches and
considered opinions of the authors.

Amidst the press and rush of modern research, and the
multitude of papers published in many tongues, it is necessary
to find men of proved merit and ripe experience, who will
winnow the wheat from the chaff, and give us the present
knowledge of their own subjects in a duly balanced, concise,
and accurate form.

Major McCay deals with a subject of fundamental importance
— viz, the amount of protein required in nutrition. From pro-
longed inquiries into the habits and physique of the tribes and
races of India, he brings forward a body of evidence which proves
thata high protein ratio is necessary in child life to produce a
virile and active race of men. Major McCay has had splendid
opportunities in the material afforded him by the prison dietaries
of India, and he has utilized these to the fullest advantage. His
final conclusions are in opposition to those of Chittenden, and
demand the closest attention of all, and particularly of those
who have to deal with dietaries for the young in schools and

institutions.

LEONAED HILL.
WILLIAM BULLOCH.
September, 1912.

V

280288

AUTHOR'S PREFACE

THE object with, which, the following pages have been written
is to present to the reader a broad view of the subject of nutrition
in the light which recent investigations have shed on the problems
connected therewith.

Since the publication of the volumes dealing with Chittenden's
views on the protein requirements of the body, a very con-
siderable amount of investigation has been quietly going on.
Sufficient time has now elapsed, since his first onslaught on the
generally accepted opinions held with regard to the level of
nitrogenous interchange within the body necessary for the
maintenance of a healthy man of average weight and doing a
moderate amount of work in health and in a state of efficiency,
to permit of definite conclusions being arrived at.

It is meet, therefore, that the stage now arrived at in the
determination of the ideal form of the dietary of mankind
should be placed on record. Such a record, the author hopes,
will be found in the matter set forth under the following chapters.

In the present volume the author has made use of the observa-
tions and investigations of a great many of the more important
recent publications on the subject, and has attempted to show
that the weight of evidence is entirely against the great reduc-
tion of the protein content and caloric value of the dietaries of
mankind so strongly advocated by Chittenden.

Recent investigations by different research workers have
shown that it is possible to reduce very considerably the quantity
of protein necessary to maintain an animal in nitrogenous equi-
librium, when the particular nitrogenous compounds required
by that animal only are given in the food. In fact, at the

vi

AUTHOR S PREFACE Vll

present time, no one denies the feasibility of maintaining either
man or animals in a condition of nitrogenous equilibrium on
quantities of protein very much below the standards set up by
the old 'masters in the science of nutrition.

If we knew exactly how much, and what particular nitrogen
compounds the body requires in each specific state of nutrition,
it is rational to expect that it would be possible to maintain the
body in health, vigour, and efficiency on quantities of protein
very much less than those hitherto considered necessary ; but,
as we do not know what form of nitrogen combination nor how
much of any particular unit is required in the different states of
bodily nutrition, it is surely only rational that, in order to insure
a sufficiency of those elements absolutely essential, a liberal
standard of dietary should be recommended. The work of Leonard
Hill and Flack on flours, and the researches carried out on the
production of beri-beri by feeding animals on rice deprived of
certain of its outer layers, show how important certain minute
constituents of the food may be.

It seems, therefore, only reasonable to lay down such a
standard of protein in the feeding of man as will at least give
to the body the opportunity of obtaining the particular com-
binations it requires in any given state of nutrition.

This deduction is fully borne out by a careful consideration
of the information available from dietary studies carried out
in many different countries, and particularly by the investiga-
tions made in India to determine the effects of different degrees
of protein interchange on several tribes and races living under
exactly the same conditions, except as regards diet. An abso-
lutely dispassionate survey of the physical development and
general capabilities of the races and people of India points
undoubtedly to the conclusion that, other factors being elimin-
ated, those who obtain a liberal supply of absorbable protein
in their daily food are superior in every respect to those whose
dietaries exhibit any marked degree of lowering of the average
protein standard.

The general conclusion arrived at, from a broad consideration
of all the facts available in the present state of our knowledge,
is that the views held by the older writers on nutrition are
sounder and more in accord with the findings of careful scientific

viii AUTHOR'S PREFACE

study than are those of the newer school. Voit, who may be
taken as a distinguished representative of the former, stands
to-day absolutely vindicated ; whilst the earnest plea put for-
ward by Chittenden, for a lowering of the protein and caloric
value of dietaries by large amounts, cannot be regarded as longer
possible, in the light of the accumulated evidence of the ill-
effects that follow in the train of chronic underfeeding.

The photographs, illustrating, so far as it is possible to do so,
the physique of the different races and tribes investigated, have
been very carefully selected as being as nearly as possible typical
of the average development met with.

The author tenders his grateful thanks to all those whose
works have been of assistance in the argument set forth ;
wherever possible full acknowledgment has been made in the
text. He wishes particularly to thank his assistants in the
laboratory, without whose willing co-operation much of the
work herein recorded would have been impossible of performance.

D. McCAY.

PHYSIOLOGICAL DEPARTMENT,
MEDICAL COLLEGE,
CALCUTTA.

July, 1912.

CONTENTS

PAGES

CHAPTER I.— INTRODUCTION - 1—22

vThe importance of protein - - 1
Advances in our knowledge of the changes taking place during diges-
tion and assimilation of protein -

End-products of protein hydrolysis - - 5

The importance of certain necessary end-products in nutrition - 6

The necessity of a liberal degree of choice - - 10
^The significance of the denitrification of proteins

Schryver's investigations - - 13
Folin's views on the significance of urinary creatinine and neutral

sulphur ... . 15
Later workers on the excretion of creatinine : Van Hoogenhuyze,

Verploegh, Paton, Dorner, and Cathcart

Mellanby's study of creatinine excretion - - - - 17

Schaffer's „ - 17

Levene and Kristeller's investigations - 1 8
Conclusions arrived at with regard to the significance of urinary

creatinine - 20

CHAPTER II.— THE FOOD OF MANKIND - 23—35

The functions of food - - 23

The great variations in the food of mankind - - 23

Widespread striving after a mixed form of alimentation - - 24

Dr. Harry Campbell on the evolution of man's diet - - 26

His conclusions - - 30

The chemical composition of European and Indian food materials - 31

Heat values of Indian food materials - - 32

The digestibility and absorbability of foodstuffs - - 33

Results obtained in Europe and America summarized - - 34

CHAPTER III.— TROPICAL FOOD MATERIALS AND THEIR DIGES-
TIBILITY - 36—66

Peculiarity of tropical food materials - - 36

Rice as a food - - 37

Deficiency in protein - 37

Its bulkiness - 38

Inferiority of its protein absorption - - 39

Wheat as a food - 42

Protein absorption of good wheat - - 43

,, of inferior wheat - 43

Effects of modern methods of milling - 45

The demand for " standard bread " - 46

Effects of bleaching - - 47

of adding " improvers " - 48

ix

CONTENTS

CHAPTEE III.— TROPICAL FOOD MATERIALS AND THEIR DIGES-
TIBILITY— Continued

Relative values in nutrition of white bread, standard bread,

and wholemeal bread - 50

Conclusions arrived at - 51

Maize as a food - 52

Protein content and protein absorption - - 53

Its suitability as a food - - - - 54

Barley as a food - 54
Protein content and protein absorption

Juar as a food - 55

Protein content and protein absorption - - 55

Bajra as a food - - 55

Protein content and protein absorption - - 55

Foodstuffs derived from the Leguminoseae - 57

Chemical composition - - 57

Their importance in the East - - 58

Work done on protein absorbability - 59

Effects of bulk on protein absorption - 60
Percentage absorption of the protein of the different

legumes - 62

Summary of results obtained for the coefficients of the digesti-
bility of tropical food materials - - 65

CHAPTER IV.— THE PROTEIN METABOLISM OF MANKIND 67—95

Scientific study of dietetics - - 67

Importance of Chittenden's work - - 68

Dietary standards, methods of arriving at - 68

Generally accepted standards -

Benedict's estimates of average food consumption - - 70

Selection of average dietaries in Europe and America - 70

Caloric values of army rations in peace and war

Atwater's standards -

Tropical dietaries : Oshima's researches

Rice not the principal food material of the tropics - 73

Dietary studies in Japan

Values of army ration of different nations

Dietary of jinricksha man of Japan

Effects of alteration in the Japanese Navy dietary

Dietary studies in India

- 74

- 74

- 74

- 76

- 76
First study : Students and servants of medical college - - 76

Bengali and Japanese contrasted

Bengali and Chittenden's deductions - 77

Second study : Two medical assistants of medical college
Third study : Diet scales of different classes of Bengalis -

Preference for a mixed type of dietary - - 80

Chittenden's misconception of Bengali's diet discussed : his

criticisms answered - - 81

Chittenden's experiment on six assistants examined : his
figures corrected

Ordinary Bengali diet not ill-balanced - 85

Fourth study : Residential colleges : students' dietaries - 85

Fifth study: Dietaries of hill- tribes of Bengal: Bhutias, Sikhimese,
and Nepalese

Nitrogenous metabolism per kilo of body weight - - 87

Sixth study : Dietaries of aborigines of Chota Nagpur -

The meat-eating Todas and salt

Nitrogenous metabolism of aborigines
Seventh study : Dietaries of the fighting castes of India - - 89

The foodstuffs of the Sikh - - - - - 90

CONTENTS xi

CHAPTER IV.— THE PROTEIN METABOLISM OF MANKIND— Con-
tinued PAOES

Nitrogenous metabolism of the Sikh - 91

Dietary of the Sikh soldier - - 91

Sikhs not vegetarians - - 91
Eighth study : Composition of Bengali and European mother's

milk contrasted - - 92

Bengali mother's milk deficient both in quality and quantity 93

Average weight of new-born European and Indian infant - 94
Suggested influence of diet on the composition of Indian

mother's milk - - 94

Effects of defective nutrition on the Indian infant - - 94

CHAPTER V.— THE PROTEIN REQUIREMENTS OF MANKIND 96—121

Dietaries considered from standpoint of protein element and caloric

value - - 96

Loss of potential energy owing to intestinal fermentation - - 97
The nitrogen of the faeces a true measure of the nitrogen lost to the

body - 99

/ The protein requirements of the body - - 100

Evidence afforded by the average consumption of mankind - 100

Chittenden's criticism of this evidence - - 101

Crichton- Browne on Chittenden's objections - - 102

Hutchison's opinion - - 102

Sir William Roberts's opinion - - 102

Evidence afforded by deductions from Folin's observations on

urinary creatinine - - 103
Evidence afforded by a study of the conditions that obtain

during starvation - 104
The lower limits of nitrogenous equilibrium approximately

determined - 106

The lower limits not the most advantageous - 107
The increased demand for protein during severe muscular

exertion - 107

Paton's investigations and his conclusions - - 108

The role of protein in muscle work discussed - 109

Stewart's opinion - 110

What the ordinary level of protein interchange really

amounts to - 112

The only way of arriving at the true protein needs of the body - 113
Results obtained from man as to the effects of diets poor in

protein - - 113

Different observations summarized - - 114

Chittenden's unique investigations - - 114

The long experiment on himself - 114

Points of interest referred to - 115

His three groups of subjects - - 116

Points of interest referred to - - 116

Chittenden's conclusions as to the protein requirements of

the body - 118
Chittenden corroborated by :

Caspari and Glassner - - 118

Hamill and Schryver - - 118

The teeming millions of Bengal - 118
Chittenden's most recent work on the degree of protein

metabolism exhibited by students - 118

The conclusion drawn from his findings - 119

His work on students adversely criticized - 119
His figures corrected and shown to disprove the view

he advocates ..... 121

xn CONTENTS

PAGES

CHAPTER VI.— THE MERITS AND DEMERITS OF DIETARIES

POOR IN PROTEIN - - 122—148

Chittenden's beliefs regarding danger of excessive protein - - 122

Foundations for such beliefs not considered valid - 123

Criticisms by Hutchison, v. Noorden, and others - 123
Chittenden's three groups of experiments, conditions observed,

results seemingly obtained, discussed - 124
Benedict's critical examination of Chittenden's experiments on

soldiers of the Hospital Corps - - 124

Benedict's criticisms elaborated and discussed - - 125

The causes of Chittenden's discordant results examined - - 128

Conclusions arrived at - 129

Chittenden's studies with eight athletes - - 130

Significance of their loss in body weight - 131

Regretful absence of controls 131

Objections to and criticisms of Chittenden's experiments

and deductions therefrom summarized - - 132

Other criticisms of a more general nature summarized - 133

Nietzsche on the effects of a rice dietary - 134
Mullick on the medical aspects of student life in

Calcutta - - 135
Evidence afforded by the dietaries of local and convict prisons in

England - - 135

Dunlop's work for the Prison Commission of Scotland - - 136

French prison dietaries - - 136
Other lines of evidence bearing on the effects of dietaries poor in

protein :

Darwin's observations on miners in Chili - 137

Livingstone's observations on tribes of Central Africa - - 137

Zieman's study of coloured races in Africa - - 137

Irving Fisher's tests of no scientific value - 138

Intercollegiate tests in Calcutta and deductions therefrom - 138

Evidence afforded by the negro, poor white, and Italian labourer 139

Evidence afforded by the successful races of mankind - - 140
Experiments on animals :

Munk, Rosenheim, Hagemann, and Jagerroos - - 140

Chittenden's experiments on six dogs - - 140

His work and findings unfavourably criticized - - 141

Further criticisms • - 142

Evidence afforded by the feeding of swine on a low and high

protein dietary respectively - - 143

Similar experiments on cows - - 144

General summary of the evidence adduced - - 145
Doubts strengthened by a consideration of the caloric values of

diets - - 146

Benedict's observations on Fletcher - - 146

Heat value of diet of soldiers insufficient - 147

Most probable explanation of discrepancy - - 148

CHAPTER VII.— THE EFFECTS OF A LOW PROTEIN DIETARY IN

THE TROPICS - 149—178

Orme on the effeminacy of the inhabitants of Indostan - 149

The cause of this effeminacy — a rice diet - 150

Scrafton on the effects of a rice diet - - 150

Cambridge ,,,,,, - 151

Strachey's opinion - 151

The temptation to follow Chittenden's lead - - 152
Regretful resistance after a study of the results accompanying a

low protein intake - 153

Macaulay on the characteristics of the Bengali - - 154

Strachey's comments thereon - - - - 154

CONTENTS Xlll

CHAPTER VII.— THE EFFECTS OF A LOW PROTEIN DIETARY IN

THE TROPICS— Continued pAQKs

Brahmin proverb exemplifying the effects of diets deficient in protein 155
Facts bearing on the conditions that obtain with the Bengali rice

dietary - - 155

1. The evidence afforded by a study of the urine and blood - - 156

Tables contrasting the composition of the urine and blood of

Europeans and Bengalis - - 156

Differences examined and significance discussed - 157

Deductions drawn and conclusions arrived at - - 159

2. The evidence afforded by contrasting the physical development of

Bengali and Eurasian students living under identical con-
ditions, but on different dietaries - - - 160
The dietaries of the two classes of students - - 161
Results : Bengali students - - 162
Eurasian students - 162
Their significance in estimating the merits or demerits
of diets low and relatively high in protein re-
spectively - - 163

3. The evidence afforded by a study of the physique, endurance,

capabilities of work, and expectation of life in the Bengali - 164

(a) Body weight of Bengali shows a low average - - 164

(6) Height: comparatively tall - - 165

(c) Chest girth well below European average - - 165

(d) Physical endurance very deficient - - 165

(e) Capabilities of work - - 166
(/) Expectation of life at different ages - 167

Mortality rates favourable to Mohammedans as compared

with Hindus - - 167

Evidence collected from insurance companies - - 168

An actuary's opinion - - 168

Dr. Adrian Caddy's valuable data - 168

Dr. Caddy's results summarized - - 169

Conclusions arrived at - - 171

4. The evidence afforded by the resisting power to disease and in-

fection - 171
No evidence that an ordinary diet throws any strain on the

kidneys - 172
Strong evidence that diets deficient in protein are accompanied

by malnutrition of renal epithelium - - 172
Incidence of renal disease in the Bengali

Major Rogers's analysis of post-mortem records - 173

Resisting power of low protein feeders to acute infections very low 175

Granular kidney and atheroma ----- 177

CHAPTER VIII.— THE EFFECTS OF THE LEVEL OF PROTEIN
METABOLISM ON THE PHYSIQUE AND GENERAL
EFFICIENCY OF DIFFERENT TROPICAL TRIBES AND
RACES - - 179—210

Other factors besides diet as the cause of defective development - 179

Chittenden's explanation not valid - 179

Dr. Kellogg's criticisms - - 180

The causes put forward by Kellogg eliminated - - 180
Peoples of Behar, Lower Bengal, Orissa, and Eastern Bengal

contrasted - - 181
The true facts regarding the level of nutrition and the fighting

instinct 182
The evidence obtained from an examination of the dietaries of the

hill tribes of Bengal and their physical development - 184
The level of protein metabolism and the conclusion arrived at

as to its effects ...-,, J.87

xiv CONTENTS

CHAPTER VIII.— THE EFFECTS OF THE LEVEL OF PROTEIN
METABOLISM ON THE PHYSIQUE AND GENERAL
EFFICIENCY OF DIFFERENT TROPICAL TRIBES AND
RACES— Continued pAQEg

The evidence afforded by a study of the races of the Gangetic Plain - 188

The different physical types - - 189

Rajputs : Eastern and Western - - 191

Western, superior as soldiers - - 192

Effects of differences in diet - 192

Physical development of Rajputs - - 193

Dogras : Rajput Highlanders - 193

Growth of caste system - 193

Characteristics of the Dogras - - 194

Effects of diet on physique - 195

Diet and foodstuffs of Dogras - 195

Different classes of Dogras : Effects of diet on :

(a) Dogra Brahmins - 196
(6) Dogra Rajput :

i. Mian Rajput - - 196

ii. Rana and Thakur classes - 197

iii. Rajputs of the Plains - - 197

iv. Lower classes of Dogras - 197

Summary of available information on the effects of

differences in diet - - 197

Diet and physique of Dogra recruits - - 198

Jats : Eastern and Western Jats - - 199

Differences in diet and religion - 199

The Jat Sikh : His diet - - - 200

His physique - - 201

Summary of evidence collected - - 201

The Sikh : Characteristics - - 202

Effects of Sikhism - - 203

Effects of diet - - - - - 204

Physical development - - 204

Summary and conclusions - - 205

The Pathan : His food - 205

Characteristics - 205

Physique - 205

Summary of the importance of a high level of

protein metabolism - - 206
Other Indian frontier tribes illustrate the importance of
protein, such as the Afridis, Waziris, Bajouris, Baluchis,

and many others - 206
Further evidence afforded by the investigations of the Com-
mittee on the physiological effects of food,

training, and clothing on the soldier - 207

Lieut.-Colonel Melville's opinion - 207
Aron's experiments on the effects of a restricted diet

on growing dogs .... 208

His conclusions - - - - - 208
Their close correspondence with the conditions
that obtain in the rice-eating Bengali and

Ooriya - - - 208
The influence of certain substances, present in the food in small

quantities, on nutrition - - 208

Hill and Flack's researches - 209

Funk's isolation of beri-beri vitamine - - 209
Experiments to show that the absence of these bodies from the

food will not explain the poor physique of the Bengali - 210

Points raised, discussed - - 210

INDEX - - - - - - - - - 211

LIST OF PLATES

FACING
PAOE

I. (a) BENGALI; (6) OORIYAS - - 58

II. (a) A GROUP OF RICE-EATING OORIYA CHILDREN ; (6) A GROUP

OF BETTER-CLASS OORIYAS - - 86

III. (a) TIBETAN BHUTIA ; (6) NEPALESE OR BHOTANESE BHUTIA - 108

IV. SIKHIM BHUTIAS - 156
V. NEPALESE COOLIES FROM NEPAL - 172

VI. (a) TIBETAN WOMAN FROM GYANTZE ; (6) TIBETAN WOMAN

FROM LHASSA ; (c) NEPALESE WOMAN FROM NEPAL - 186

VII. (a) PUNJABI MOHAMMEDAN ; (6) DOGRA - 194

VIII. (a) RAJPUT ; (6) SIKH ; (c) PATHAN - 204

PHOTOGRAPH OF RICE-EATING BENGALI COOLIES - page 177

xv

THE PROTEIN ELEMENT IN
NUTRITION

CHAPTER I

INTRODUCTION

" The life-processes consist in the metabolism of the proteins." — VERWORN.

THE important part played by the complex body protein and its
allied nitrogenous compounds is acknowledged by all students of
nutrition.

As a food material it is the one constituent that is indis-
pensable ; it is the only substance of the three main classes of
proximate principles that is absolutely essential for the carrying
out of those vital phenomena whose aggregate may be considered
to represent the processes of life.

The more important tissues of both animal and vegetable life
consist largely of this protein material, and it is in connection
with the changes protein undergoes within the living organism —
the chemical changes by which the protein of the food is prepared
for absorption and incorporation into the bioplasm, the changes
which it undergoes while it shares in the life of the tissues, and,
finally, those by which it is broken down again into waste
products and eliminated from the body — it is in connection with
these that much of the interest in the subject centres. It is but
natural, therefore, that the chemistry of metabolic processes
should have attracted the attention of large numbers of investi-
gators. The result of this has been that the literature of the
subject has already attained enormous proportions.

Progress, despite the vigorous activity displayed by a yearly
increasing number of workers in physiological chemistry, has
not been very conspicuous. In recent years, however, owing to
the introduction of new methods of attacking the problems

2 TiKE wpROTBIJSTk. ELEMENT IN NUTRITION

connected with protein metabolism, remarkable advances have
been recorded, particularly with regard to the nature and
chemical constitution of the proteins and their cleavage products.
By the process of breaking down the large complex protein
molecule into smaller, less complex bodies or units, and by the
method of building together again such cleavage products into
substances in many respects similar to the ordinary nitrogenous
compounds, much light has been thrown on the nature of proteins
and on the arrangement of their molecules. The main results of
these investigations are to show that the protein molecule is built
up of a series of units or organic radicles — the amino-acids —
which form the basis of their composition. These amino-acids
may be looked upon as the building-stones or units of the protein
molecule, and it is in virtue of their presence that the protein
molecule possesses the peculiar property of building itself up
into bodies of high molecular weights. The results obtained by
means of hydrolytic agents on the different proteins show defi-
nitely that they are all composed of the same units ; in some
cases certain organic radicles or building-stones are missing, and
in some cases certain of these building-stones are greatly in excess.
The importance of these discoveries can only be grasped when
it is borne in mind that the old views regarding the changes in
protein material during digestion are rapidly undergoing modifica-
tion. The fact that proteins are an essential part of the food of
all animals was interpreted to mean that no synthesis of proteins
occurred in the animal body, so that all proteins in existence
must necessarily be the products of the vegetable cell. In fact,
on this basis a fundamental distinction was drawn between the
nutrition of plants and animals. The long dominant doctrine
of Liebig, that plants in the main live without protein food, and
are able to construct their own proteins for themselves, whilst
animals have to find their proteins ready-made in their food and
are unable to build them up, no longer holds good. The further
the study of the nature and constitution of the different proteins
advanced, the more clearly evident did it appear that animal and
plant proteins were different in type ; the investigations in the
science of serology would even make it practically certain that
\ the protein of one species of animal is quite different from that
of any other species, and even the proteins of the different organs
of animals of the same species differ from one another.

At present our conception of the effects of the digestive enzymes

INTRODUCTION 3

is very different from what was held to be the case even a few
years ago. The indiffusible colloid substance, protein, was
formerly supposed to be modified in such a manner by the hydro-
lyzing agencies of the intestinal tract that, as a final product,
peptone — a diffusible substance — was formed. The trypsin of
the pancreatic juice was known to be able to carry the hydro-
lysis beyond the stage of peptone, but Kuhne, who first investi-
gated its action, arrived at the conclusion that trypsin was only
able to affect half of the protein molecule. It is now known that
both pepsin and trypsin can liberate very many of the products
of acid proteolysis, and to a great extent destroy the protein
character of the substance on which they act. Further, the
ferment erepsin of the succus entericus is able to cause a more
complete breaking down of the peptones and albumoses that
have escaped the action of pepsin and trypsin, so that most
observers are unanimous in thinking that the hydrolysis of
proteins in digestion is complete. In the light of recent work it is
evident that the breaking down of the protein molecule of ingested
material, due to the action of the digestive enzymes, goes on to
the actual splitting up into organic radicles — the amino-acids and
other crystalline derivatives. These derivatives of protein
digestion — a large number of which have now been isolated and
many of them synthesized — resemble in the main the units or
building-stones obtained as cleavage products in the acid hydro-
lysis of proteins in vitro. There is experimental proof that the
final products of tryptic digestion are able to take the place of
protein in the food. Otto Leowi maintained a dog in complete
health with an increase in body weight on the products of
pancreatic digestion, the chemical observations showing that no
protein was present in the food, and that the daily amount of
nitrogen metabolized was less than that ingested. Henriques
and Hansen have successfully carried out similar experiments
on rats, and have confirmed these results. From the building-
stones or cleavage products of protein digestion the body is,
therefore, capable of building up its bioplasm, and of making-
good the wear and tear of everyday life ; in doing so, in all
probability, different sets of units or amino-acids are made use of
in the formation of the many different types of nitrogenous
material required by the several tissues of the body. That is, the
material out of which all proteins in the body are made is not
protein in any form, but the organic radicles derived from proteins

4 THE PROTEIN ELEMENT IN NUTRITION

by hydrolysis, which in different combinations and in different
proportions are found in the proteins of the different tissues,
these different combinations and proportions conferring on the
nitrogenous material of the several organs and tissues a specific
character.

But while the cleavage products of the intestinal digestion of
proteins are able to maintain an animal in nitrogenous equilibrium,
those formed by the hydrolytic action of mineral acids are quite
unable to do so ; animals fed on these substances live no longer
than other animals whose food contained no nitrogenous materials
at all. There is therefore some difference in the hydrolytic action
of the digestive enzymes as contrasted with that of mineral acids,
although the products obtained by the action of these two hydro-
lyzing agents are to a large extent identical. However, it is
evident that the acid breaks up some building-stone or stones
which the digestive ferments retain, and which are absolutely
essential in the synthesis and nutrition of the bioplasm. What
the nature of those organic radicles may be whose presence are of
such importance in the assimilation of the products of tryptic
digestion, at present it is impossible to say. It may be, as
Leathes suggests, that there is some kind of linkage between
certain groups in the protein molecules "which is not broken down
by the digestive enzymes, but is in acid hydrolysis. When this
coupling is destroyed, it is impossible for the cells of the body
to make use of these groups, and successfully resynthesize them
into materials necessary for the nutrition of their bioplasm.

The study, therefore, of the intermediate stages in the processes
of protein metabolism has opened up a field for research, which has
been and is being successfully cultivated. As pointed out above,
the researches of Fischer, Kossel, Schutzenberg, and a host of
others have thrown a A1ood of light on the composition of the
protein molecules. Protein has been shown to consist of a com-
plicated chain of units capable of being broken down into bodies
of gradually decreasing complexity. Thus, the first real decom-
position products of acid or enzyme proteolysis are the albumoses
which exhibit distinct characteristics, and are easily isolated by
precipitation with ammonium sulphate. The next products — the
peptones — are less definitely characterized, and are at present
identified by one positive reaction — the biuret test. Fischer has
applied the term " peptides " to a number of bodies which are
derived from peptones, but which no longer give the biuret test.

INTRODUCTION 5

These peptides contain several molecules of crystalline organic
radicles — the amino-acids — and break down into these on further
decomposition. Finally, a large number of simple end-products
of protein hydrolysis have been discovered, isolated, and, during
the last few years, many of them have been synthesized. These
bodies have been classified by v. Noorden into the following
groups :

I. Monamido- Acids :
(a) Monobasic —

Glycocoll, alanine, serine, isoserine, amido-
valerianic acid, leucine, tyrosine, and
phenylalanine.
(6) Dibasic —

Aspartic acid and glutaminic acid.
II. Diamido- Acids :

Lysine and arginine.

III. Indol- and Skatol-Producing Group :

Tryptophane, skatolamino-acetic acid, or indo-
lamino-propionic acid.

IV. The Pyrrol Group :

Pyrrolidine-carboxylic acid.
V. The Pyrimidine Group :

Histidine.
VI. The Carbohydrate Group :

Glucosamine.

VII. The Sulphur-Carrying Group :
Cystine.

The simplest of the amino-acids contain one organic radicle
and one basic radicle — the acid character being due to the
carboxyl group COOH, and the basic character to the amidogen
group NH2. Amino-acids containing only one amidogen group
are classed as " monamino-acids," as CH2(NH2).COOH, glycocoll,
or mono-amido-acetic acid ; others possessing two such basic
groups are termed " diamino-acids," as CH2(NH2).(CH2)3.
CH(NH2).COOH, " lysine," or " ae-diamido-caproic acid." In
the majority of the amino-acids there is only one carboxyl group,
but sometimes there are two or more such groups, and then they
are classed as " monobasic," " dibasic," etc. One of the peculiar
characteristics of these amino-acids is their power of undergoing

6

THE PROTEIN ELEMENT IN NUTRITION

conjugation or condensation with one another, or with other
organic radicles, to form more complex bodies with high molecular
weights. So far, however, all attempts to build up proteins
from the amino-acids have failed. Emil Fischer has built up
bodies which he calls " polypeptides," by the condensation of
glycocoll, leucine, and other amino-acids. It is hoped that the
formation of these bodies may be the first step in the process of
protein-synthesis .

Another important discovery in connection with the formation
of the intermediate products of protein metabolism is that the
cells of nearly all the organs of the body have been shown to
possess enzymes capable of breaking down the complex protein
molecules, and causing disintegration as complete as in the action
of the ferments of the intestinal tract. That the breaking down
of the nitrogenous tissues begins as a result of the action of these
cellular enzymes is most probable, and is supported by the fact
that some of the products of protein hydrolysis are found in the
bile and urine, having escaped further destructive changes which
would have terminated in them being excreted as urea or other
nitrogenous constituent of the urine. Glycocoll is an example
of one of the products which has escaped this fate ; by its union
with cholaic acid it is found in the bile as glycocholic acid, and
with benzoic acid it occurs as hippuric acid.

Another property of the cells, again probably the work of an
intracellular enzyme, is their power of liberating ammonia from
the amino-acids. This power is most marked in the cells of the
intestinal mucous membrane and liver, which would explain the
fact that the percentage of ammonia in the portal blood is during
digestion several times greater than that in the systemic blood.
The significance of this power of the cells of the intestinal mucous
membrane and liver of denitrifying the hydrolyzed products of
protein digestion is not clear ; but it has been explained as being
a reaction which, while leaving the non-nitrogenous part of the
protein molecule untouched, facilitates the greater part of the
nitrogen of the hydrolyzed products of protein digestion in being
eliminated in the urine as urea. The speed with which a large
part of the nitrogen appears in the urine as urea, following on the
ingestion of a protein meal, has been taken as a sign that the
body does not require all the nitrogen, and that it must be got
rid of before the valuable part of the protein molecules is admitted
into the general circulation. This is effected by the denitrifying

INTRODUCTION 7

action of the enzymes of the cells of the intestinal mucosa and
liver. The fact that the greater part of the nitrogen of the food
is quickly eliminated, and never reaches the tissues of the body
at all, suggests at once that the amount of nitrogen provided in
ordinary dietaries is too great. This is a subject which will
require very careful consideration ; at present, all that need be
said is that this denitrification has not been proved to apply to
all the products of protein digestion. In fact, it is very doubtful
if it occurs at all, or at least to any great extent, in those amino-
acids or building-stones that are absolutely essential for the
nutrition and repair of the bioplasm. It may be that only the
ordinary amino-acids, which probably have to be taken in
excessive quantities in order that there may be a sufficiency of
the more important compounds, undergo denitrification with
speedy elimination of their nitrogen as urea in the urine. Thus,
tyrosine and phenyl-alanine are said not to increase the output of
urea when injected into the blood ; and histidine, which contains
a nitrogenous group related to one of those found in nucleic acid,
does not give up its nitrogen in the form of ammonia. The
feeding experiments of Kaufmann and Murlin with gelatin, where,
in spite of a very large intake of nitrogen, equilibrium could not
be maintained, while great improvement in the conditions
occurred when small quantities of aromatic bodies, normally
absent from gelatin, were added ; the work of Hopkins and
Willcock on zein, where marked effects followed the addition of
tryptophane to the diet — these and other experiments of a similar
nature would appear to show that in a diet it is not so much the
actual amount of nitrogen that is of importance, but that the
food ingested must contain a sufficient amount of the particular
building-stones necessary for growth and repair.

In accordance with this view the work of Michaud is most
important, as demonstrating that the intake of nitrogen can be
reduced to a minimum, and nitrogenous equilibrium maintained
when the food contains nitrogenous compounds in the pro-
portions suited to the animal's requirements ; this he effected by
feeding animals on the flesh of their own species — a dog on dog's
flesh. It is probable that in breast-fed infants the milk presents
the necessary ingredients in the proper proportions, so that the
hydrolysis of the proteins in the digestive tract, and the subse-
quent synthesis of the cleavage products into the proteins of the
tissue cell, can take place with a minimum amount of waste.

THE PROTEIN ELEMENT IN NUTRITION

Further, it is known that certain substances formed in certain
organs are absolutely necessary in the maintenance of health,
as, for instance, the substances elaborated by the suprarenals,
thyroid, pituitary body, etc. Adrenalin is derived from an
aromatic precursor, and Hopkins believes that the suprarenal
requires a constant supply of some one of the aromatic groups of
the protein molecule to serve as an indispensable basis for its
elaboration. If such a constant supply is not available, as, for
instance, in starvation, a precursor would have to be provided by
the breaking down of some of the tissues of the body.

In connection with the necessity of the body being provided
with the particular combinations of units suited to its needs, it
is important to bear in mind that the proteins contained in food—
whether animal or vegetable — are different in composition from
those found in the tissues of the body. The products obtained
from various proteins on hydrolysis show very marked differences
in the proportions of the various amino-acids. These differences
are well brought out in the table opposite.

It is evident, therefore, that in protein metabolism the body
selects the particular combinations it requires, and builds them
up into its own peculiar types of nitrogenous matter, and that
the type of protein supplied in the food is of little importance, so
long as it is capable of furnishing a sufficiency of the particular
types of amino-acid needful in the synthesis of tissue proteins.
The feeding experiments with gelatin, already referred to, is a
good instance of the importance of the presence of special com-
binations of molecules in the food. The role of protein in the
diet cannot be undertaken by gelatin because, although gelatin
can be broken down into different amino-acids, such as arginine,
lysine, histidine, etc., it is unable to provide tyrosine, trypto-
phane, or cystine, all of which are essential in the synthesis of
tissue proteins. The addition of these bodies to a diet of gelatin
enhances its value enormously, so that it may even take the place
of true protein. Further proof of the power the tissues possess
of forming their own particular types of protein, whatever the
diet may be, is forthcoming in the experiment of Abderhalden,
who bled a horse until a large quantity of the serum-protein was
lost. The animal was then fed on gliadine, which contains four
times as much glutamic acid as horse's serum-protein ; in spite
of the absorption of glkdine the serum-protein of the horse's blood
remained the same. The same holds good for the vegetable

INTRODUCTION

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10 THE PKOTEIN ELEMENT IN NUTRITION

protein, zein, experimented with by Hopkins and Willcock.
Zein, given in the food, cannot be recovered from the tissues, and
in all probability certain of its amino-acids are made use of to
build up tissue protein ; certain other units, not being of the
particular composition required, are rejected and eliminated as
waste.

From the standpoint of the synthesis of tissue proteins by
selection of those particular amino-acids or units that are suitable,
it will be acknowledged that, in the proper nutrition and growth
of the nitrogenous tissue, a protein diet in excess of the actual
requirements will be necessary, in order that the body tissues
may have plenty of choice. This principle would hold good for
all proteins, but especially for protein of vegetable origin, for, if
the amino-acids formed during digestion are not present at all,
or not present in the necessary proportions, and this is all the
more likely to be the case with vegetable proteins, then, the
suitable groups being relatively scanty, much unsuitable protein
will require to be hydrolyzed in order that the proper supply of
the essential units may be obtained. In the light of the opinions
at present held regarding protein synthesis within the body,
these considerations would forcibly combat the view that has
been put forward that great benefits would accrue to the economy
from dietaries low in protein, unless it could be absolutely
insured that the low protein dietary supplied just those particular
amino-acids in sufficient quantities which the body required.

The modern views held regarding the substance protein, the
changes that are brought about during digestion, its fate after
absorption, and the processes by which it is finally broken down
into waste products, may now be briefly summarized.

By the united efforts of the three ferments, pepsin, trypsin, and
erepsin, the breaking down of the protein molecules during
digestion is a far-reaching process, the protein being disinte-
grated into a series of organic radicles, of which the amino-acids
are the most important. These amino-acids may be looked on
as the units or building-stones from which the protein molecule
is made, the numbers and combinations of these units differing
in different proteins, and being by no means the same in the
proteins of the food as in the body proteins. During this demo-
lition of the protein molecule into amino-acids, the protein loses
but little of its potential energy.

These amino-acids are taken up by the epithelial cells of the

INTRODUCTION 11

intestinal mucous membrane, and whether transformed into the
serum-proteins by these cells, or passed on into the blood as amino-
acids and other final products of hydrolysis, is, for the present,
an open question. The evidence on the whole would make it
appear probable that the products of the digestive hydrolysis of
proteins enter the blood unchanged, and are taken up by the
tissue cells at a rate not appreciably different from the rate at
which they are absorbed by the blood from the intestine. In the
somewhat analogous condition in plants during germination,
proteins, stored as food material in the seed, undergo hydrolytic
changes, and circulate in the sap in the form of amino- acids
practically identical with those formed during digestion in
animals. In the plant nitrogen is supplied to the cells in the
form of these cleavage products during the period of active
growth, and it is from these that the vegetable proteins are
built up.

Whether in the form of synthesized serum-proteins, or, what is
more likely, in the form of the unchanged products of digestive
hydrolysis, the protein of the food finds its way into the blood.
The evidence available at present would point to the conclusion
that the amino- acids, on passing through the cells of the intestinal
mucous membrane, are to a great extent, robbed of their nitrogen,
which is split off from them in the form of ammonia. This
ammonia, which Nencki found to be present during digestion up
to four times the normal amount in the blood of the portal vein,
is converted in the liver into urea and eliminated as such in the
urine. This fate, however, only befalls those units or fragments
of the protein of the food that are not required for the building up
or repair of tissue protein, or that are not required by the body
at that particular time. The units that are then in demand, and
which may be quite different from those needed for repair at a
different period, are made use of by the tissue cells for their
growth and nutrition, and for the supply of the necessary com-
plexes of molecules which are broken down during the ordinary
disintegration of living tissue ever taking place.

It has been pointed out that this seemingly wasteful method of
making use of precious protein material was open to a different
interpretation to that which appears on the surface, and to that
put forward by the advocates of the superiority of a low protein
dietary. Evidence has been adduced to show that unless the
proper and suitable building-stones were furnished in the final

12 THE PROTEIN ELEMENT IN NUTRITION

products of protein digestion, it did not matter to the body how
much protein the diet contained ; the result would be the same as
if no nitrogen were present in the food at all. The necessary
building-stones would have to be obtained from the disintegration
of the inferior tissues of the body in order that the master tissues
should be maintained as long as possible in a state of nutrition
and repair. When those particular building-stones are known
and can be supplied in the food, it has been found possible to
reduce the protein element of the dietary to a minimum. The
danger of such a procedure in the general dieting of mankind is
made apparent when it is recognized that the particular amino-
acids required in any given state of body nutrition cannot possibly
be known, and this danger is enhanced by the fact that in the
ordinary food materials, particularly in those of vegetable origin,
the amino-acids are not present in the proportions (sometimes
not present at all) necessary for the building up of tissue protein.
It is clear, therefore, that in the selection of a sufficiency of
suitable units a great many end-products of protein digestion
that are not required will be rejected — their nitrogen split off,
and got rid of as urea. In order that the body may receive a
sufficiency of the particular units it requires, a good supply of
protein in the food is essential, a supply very much greater than
what would be necessary if the suitable combinations were
offered in the diet.

But while it is true that within a few hours of the ingestion of
a protein meal seemingly a large part of its nitrogen is eliminated
as urea, it does not necessarily follow that the nitrogen split off
is of no service in nutrition. In fact, it is well recognized how
very important a part ammonia does play in those pathological
conditions where there is an over-production of acids within the
body.

In acidosis and acid intoxications it is of the greatest impor-
tance that the acids formed should be disposed of in some way
without involving any reduction in the alkalescence of the blood.
This can be effected by the ammonia derived from protein
metabolism, and which is on its way to be changed into urea.
Ammonia is, therefore, of considerable interest as one of the
chemical defences of the body against disease. By combining
with and neutralizing organic acids, sometimes formed in ex-
cessive amounts, it permits of their elimination in the urine
without depleting the blood of its important bases. However,

INTRODUCTION 13

outside this use in pathological conditions, ammonia would appear
to have an important function in the ordinary nutrition of the
body. Recent investigations by Schryver have opened up a
very interesting line of research, and if his results hold good, they
would tend to raise the status of ammonia from its present
position, as a mere by-product of little or no importance, to that
of one of the most important units in the physiological processes
of nutrition.

By means of carefully carried out experiments, he has shown
there is no evidence that the products of tryptic digestion as
such can circulate in indefinite quantities in the blood-stream,
and that there are no such bodies present in the liver. What,
then, is their fate after leaving the alimentary tract ? Schryver
finds that the difference between the total nitrogen and the
nitrogen of coagulable albumin is very high in the mucous mem-
brane of the small intestine, a tissue most intimately connected
with nitrogenous metabolism. This difference is higher in the
carnivora than in the herbivora ; it is independent of the state
of nutrition, and is the same in fasting as in the fed animal ; and,
lastly, that the bodies represented by this nitrogen are in a state
of loose chemical combination with the bioplasm, such as exists
between an enzyme and its substrate. In this state they undergo
certain chemical changes like hydrolysis or oxidation ; the
products of the change would be eliminated and carried in the
blood-stream to other parts of the organism, their place being
taken by similar bodies, the product of tryptic digestion, which
in their turn would undergo a similar series of changes.

The passage of the products of tryptic digestion through the
mucous membrane of the intestines would therefore be analogous
to a continuous chemical process. The bioplasm acts as an
enzyme or collection of enzymes, to specific points of which
side-chains are anchored ; it always keeps saturated with side-
chains, as is shown by the fact that the residual nitrogen is the
same during digestion as during a fast.

That this saturation of the bioplasm is automatically main-
tained, the following considerations would make probable :

Autolysis occurs more rapidly in the liver of a fasting animal
than in that of an animal during active digestion ; it is inhibited
by the action of ammonia and other alkalis, but accelerated by
the presence of acids, especially lactic acid. The acceleration
due to acids is a function of the absolute quantity of acid present,

14 THE PROTEIN ELEMENT IN NUTRITION

at least for sulphuric acid. Lastly, the liver eliminates ammonia
on treatment with weak alkalis, and more is obtainable from the
organ of a well-fed animal than from that of a fasting animal —
more also from carnivora than in the case of herbivora.

It is known that during the constant disintegration of living
tissue, or autolysis, bodies of an acidic nature are produced —
carbonic acid, lactic acid, etc. ; therefore, by applying the above
considerations to what is known to occur during digestion and
metabolism, it will be evident that, so long as an animal is well
nourished, there will be an excess of ammonia present, and the
tissues will show no signs of acidity. This excess, however, will
gradually disappear if the animal is deprived of food. A stage
will soon be reached when the production of acid exceeds the
amount of ammonia available for neutralization. Owing to the
acidity, autolysis will be set up, and amino-acids will be liberated.
These amino-acids would be carried to the alimentary tract, and
ammonia would be split off, as in the case of the products of
tryptic digestion. This ammonia, by restoring the alkalinity of
the liver and tissues, would inhibit the autolytic processes.
Degradation of tissue should proceed at a definite uniform
rate.

From his results Schryver arrives at the following conclusion :
In order to maintain nitrogenous equilibrium, nitrogenous
foodstuffs must be ingested in such quantities and in such form
that the amount of ammonia produced therefrom in the digestive
tract is sufficient to maintain the intracellular alkalinity of the
liver, and probably other tissues.

If this view is correct, it would mean that the ammonia split
off from the final products of tryptic digestion plays an important
role in nutrition, as it maintains the general intracellular alka-
linity, in the absence of which nitrogenous equilibrium ceases to
be longer possible. When the protein offered in the food is
deficient in either quantity or quality, the acidic processes
generated in the organism set going the autolytic enzymes ; the
amino-acids thereby liberated are carried to the side-chains of
the bioplasm of the cells of the small intestine, keeping them
fully saturated even in starvation, and free ammonia is generated
by the hydrolysis or oxidation of those bodies they replace.
This ammonia inhibits temporarily the further disintegration of
the tissues, and so long as present in sufficient amount would
favour anabolism. The anabolism and katabolism of the tissues

INTRODUCTION 15

may therefore be looked on as the result of antagonistic reactions,
the balancing of which results in nitrogenous equilibrium.

The only other point it is necessary to refer to in this summary
of the intermediate products of nitrogenous metabolism is the
importance that has been attached to the constancy in the
amount of certain of the waste products that are eliminated in
the urine. Folin has shown, and his results have been confirmed
by many observers, that the output for the same individual of
creatinine and neutral sulphur in the urine is constant, that this
output does not alter with the change from a nitrogen-rich to
a nitrogen-poor diet, and that the output seems only to vary
with the mass of the nitrogenous tissues of the body. (Cathcart,
experimenting on himself, found a distinct difference in the
output of creatinine whilst fasting and on an ordinary mixed
diet.) Folin holds that these substances, creatinine and neutral
sulphur, are characteristic of endogenous or tissue metabolism,
whilst urea and other nitrogenous constituents, the output of
which varies with changes in the composition of the diet, are
indicative of an exogenous or intermediate metabolism. From
the results obtained for the output of creatinine in the urine —
which seem to vary for the same individual under different
dietaries from 0-353 to 0-534 gramme, expressed as nitrogen — a
whole theory of protein metabolism has been built up, and great
importance has been attached to it as affording strong evidence
that only very small quantities of nitrogen are necessary to
maintain the organism in full bodily vigour — just that amount,
in fact, that is required to make good the ravages of endogenous
metabolism, of which the constant output of creatinine and
neutral sulphur in the urine is in some way a measure. The
underlying suggestion is, although Folin himself does not state
so, that these two forms of metabolism are absolutely distinct
from one another, and that urea is almost, if not entirely, an
excretory product of exogenous metabolism.

According to the older views of Liebig and Pfliiger, the products
of digestion circulate in the blood-stream, or are built up into the
bioplasm, the proteins of the blood plasma and lymph forming
the source from which the cells derive their supply. All kata-
bolism of protein material must, therefore, be preceded by
anabolism. The discovery that a large proportion of the
nitrogen of a protein meal appeared in a few hours as urea entailed
the belief that the protein absorbed from the food has been very

16 THE PKOTEIN ELEMENT IN NUTRITION

quickly built up into the living protoplasm, only to be accom-
panied, or immediately succeeded, by a similar degree of
katabolism. As this explanation did not appear very probable,
in the light of Nencki's rinding of a large excess of ammonia in
the blood of the portal vein during digestion, this view is not
regarded now as sufficient to cover the facts. It is considered
much more probable that the ammonia split off from the amino-
acids of tryptic digestion is transformed into urea in the liver,
and that the nitrogen represented by that urea never reaches
the protoplasm of the cells, but is quickly got rid of in the urine.

The constancy in the output of creatinine for each individual
has been suggested to mean that this substance is a product of
true tissue metabolism ; the one factor determining its amount
being the weight of the true tissue elements of the body. Further,
creatinine has been looked upon to some extent as a measure of
the extent of the nitrogenous interchanges within the body ; and
as the total daily output rarely exceeds 0-6 gramme nitrogen,
it has been used as an argument to support the view that only a
small amount of protein is needed in the diet. The line of
reasoning from this point of view is quite clear. Shortly, it is as
follows :

The products of tryptic digestion lose a large proportion of
their nitrogen on absorption ; this exogenous katabolism appears
to have no physiological meaning, and the extent to which it
takes place in the ordinary individual on a liberal protein diet
no justification. The constant splitting off of nitrogen appears
to serve no useful purpose, as the organism can neither use it
nor store it up for future use. The carbohydrate moiety of the
protein molecule is made use of as a source of body heat and
potential energy, but this could easily be replaced by carbo-
hydrates given as such in the daily food. Having the further
information that the nitrogenous requirements of the true
cellular tissues — as measured by the products of endogenous
metabolism — are very small, the question naturally arises,
Would it not be greatly to the benefit of the organism to lessen
the protein element in the diet to an amount closely approxi-
mating that of the true needs of the body ? This question the
advocates of a low protein dietary answer in the affirmative.
The true answer can only be arrived at by a very careful con-
sideration of the principles involved in all their bearings, and
particularly by an investigation to determine the effects of a

INTRODUCTION 17

limited supply of protein in the food on the physical well-being
of the individual or of a race.

Since the introduction of Folin's colorimetric method of
creatinine estimation, a great amount of research has been
carried out on its elimination under various conditions of diet
intake and energy output. Van Hoogenhuyze and Verploegh
made a large series of experiments to determine the effect of
exercise ; they arrived at the conclusion that muscular work
only produces an increased elimination of creatinine when the
body is forced to live at the cost of its own tissues, as in starva-
tion. Noel Paton and Dorner, later also Cathcart, found
a relation between the creatinine excreted and the intaken
protein.

The most complete study of the subject, however, is by
E. Mellanby, and the conclusions he has arrived at are of con-
siderable importance in connection with the views expressed by
Folin and others. The broad general conclusions to which
Mellanby comes are, that in the formation of creatinine muscle
plays a small part, whilst the liver, on the other hand, is inti-
mately connected with the production of creatine and the
excretion of creatinine.

He believes the liver to be continuously forming creatinine
from substances carried to it by the blood-stream from other
organs, that in the developing muscle this creatinine is changed
to creatine and stored, while after the muscle has reached a
saturation-point creatinine is continuously excreted. Mellanby
brings forward a considerable mass of evidence to support his
conclusions. The fact that in the chick creatinine is not excreted
until a week after hatching, which he shows by analyses to mean
that the muscles are not until then saturated with creatine ;
that there is almost complete absence of creatinine from the urine
of young children and also of puppies, lends added support to
his findings.

Later, Shaffer, from a careful study of the excretion of creatine
and creatinine by normal and pathological subjects, arrives at
the conclusion that creatinine is not an index of total endogenous
protein katabolism. Subjects of exophthalmic goitre and others,
in whom the total endogenous katabolism is probably much
increased, excrete very little creatinine. He states that creatinine
is derived from, and its amount is an index of, some special
process of normal metabolism taking place largely, if not wholly,

2

18 THE PROTEIN ELEMENT IN NUTRITION

in the muscles, and upon the intensity of this process appears to
depend the muscular efficiency of the individual.

Still more recently Levene and Kristeller undertook a series
of investigations as to the role of the muscular system in regulating
the creatinine output. Observations were made on twenty-four
patients affected with disease in which the muscular system was
involved. The influence of diet was also studied whenever the
creatinine output was found abnormal. Three forms of diet were
generally employed : one of low protein content, but containing
sufficient calories, the nitrogen intake not exceeding 6 grammes,
and the calories reaching 3,000 per day ; the second diet of
approximately the same calorific value contained milk and eggs,
with a nitrogen content of about 10 grammes ; and the third, a
beef diet, with a nitrogen content of 20 grammes per day. In
health these diets should not markedly influence the creatinine
output.

A review of the results brings to light the following facts :
In all pathological conditions involving the muscular system
the rate of katabolism of ingested creatine is lowered, and part
of the ingested substance is removed in the form of creatinine.
When there was dissolution of muscular tissue with diminution
of muscular activity, the output of creatinine was low and that
of creatine high. In some cases the output of both creatine and
creatinine was influenced by the protein content of the diet.
The findings cannot be interpreted adequately on the basis of any
one of the existing views on the mechanism of creatine metabo-
lism. Thus, Shaffer's hypothesis that the extent of creatinine
output is determined by muscular efficiency does not harmonize
with the observations on progressive muscular atrophy, where
there may be an extreme degree of muscular wasting, without
any marked alteration of the creatinine output. Folin's theory,
which regards the intensity of cellular katabolism as the principal
factor in influencing the creatinine output, is not supported by
these investigations. Mellanby's view, likewise, is not sufficient
to interpret the results obtained. These authors believe that in
the regulation of the creatinine output at least two factors are
concerned : the formation of the substance, very probably from
protein, and its further oxidation. Any disturbance of either
may lead to an abnormal output of creatinine.

The constant value in the amount of the creatinine output in
normal individuals is explained as being due to a condition of

INTRODUCTION 19

high velocity of creatine combustion in health. The creatinine
of the urine only represents a small fraction of the creatine
formed in the organism. The uric acid output in the dog appears
constant, as in this animal the oxidation of purin derivatives is
exceedingly high, so that only a minimal amount escapes in the
urine as uric acid. However, as soon as the liver is excluded
from the circulation, and the intensity of the purin oxidation is
diminished, the uric acid output in the dog begins to show marked
variations, influenced by the character of the food. Similarly,
the normal creatinine output in conditions of high muscular
activity may be explained by a greater power of the organism to
oxidize creatine, although creatine production in these conditions
probably exceeds the normal limits. They found, for instance,
that only 48 per cent, of ingested creatine reappeared in the
urine of a patient who was suffering with continuous tremor,
whilst in conditions of atrophy or dystrophy practically 90 per
cent, escaped oxidation, and was recovered in the urine.

More recently still Krause and Cramer, working on the effects
of thyroid feeding, find that on a meat-free diet administration
of fresh raw thyroid gland is followed immediately by a marked
rise in nitrogen excretion, which persists for several days. This
increased nitrogen excretion is accounted for by increased urea
elimination, and not by an increase in the creatinine elimination.

Since the effects of thyroid feeding on nitrogen metabolism
can be observed in the fasting organism and with a nitrogen-free
diet, it would appear that changes in the nitrogen metabolism
observed after thyroid administration are due to changes in the
tissue or endogenous metabolism.

According to Folin's view, one would expect to find a marked
increase in the excretion of such constituents as creatinine and
neutral sulphur, which he believes are the end-products of endo-
genous metabolism. The results show, however, that this is
not the case, but that the changes induced in the endogenous
metabolism of thyroid feeding result almost exclusively in an
increased formation and excretion of urea and ammonia.

In the light of these 'recent researches on the factors which
regulate creatinine metabolism, it is evident that the rate of
creatinine elimination is not a function of the intensity of cellular
katabolism, and is no measure of the total nitrogenous inter-
changes taking place within the cells of the different tissues—
i.e., between the protoplasm of those cells and the nutrient

20 THE PROTEIN ELEMENT IN NUTRITION

materials of the blood plasma and lymph. It would appear
much more probable that the formation of creatine and creatinine
represents two phases in the katabolism of one substance, the
result of a special process in normal metabolism, as a fall in th?-
creatinine output is usually associated with an increased creatine
elimination, and a high protein diet (creatine-free), in some
patients is accompanied by a rise in the output of both substances.

It has been shown by Weber that a larger amount of creatinine
is to be found in the perfusion fluid when the heart is in action ;
whilst, on the other hand, muscular exercise has been confirmed
by many observers to cause no rise in the creatinine output.
It would, therefore, follow that the creatinine formed in muscle
during its activity, and removed from that tissue by the blood
is further changed in the organism, only a small fraction of the
creatinine of muscle escaping oxidation and appearing in the
urine. According to Hoogenhuyze and Verploegh, the power to
oxidize creatinine is inherent in all organs.

It is, therefore, still very doubtful what the origin of creatinine
in the body is : whether from the nitrogenous products of the
daily food, or by some special process of normal metabolism,
according to some observers, probably intimately related to
changes in muscle. It is still more doubtful what the fairly
constant quantity of creatinine eliminated in the urine is sig-
nificant of. There seems to be a general consensus of opinion
that it represents an unoxidized fraction of the whole amount
formed in the body. There is very little evidence in the more
recent researches supporting Folin's view that it represents
endogenous metabolism, or that it can be regarded in any way
as a measure of the nitrogenous interchanges of the proto-
plasmic tissues of the organism. The deductions that have been
drawn from his conclusions regarding the origin of creatinine as
a product of cellular metabolism can no longer be considered
convincing. Thus Folin believes that the constant or endogenous
metabolism is largely represented by creatinine, and to a slight
extent by uric acid. The deduction from this in Chittenden's
words is, considering " these views so admirably worked out by
Folin, the question naturally arises, if the real demands of the
body for protein food will not be adequately met by the quantity
necessary to satisfy the true tissue metabolism." Folin also
states in the same connection that only a small amount of
protein — namely, that necessary for the endogenous metabolism —

INTRODUCTION 21

is needed. As it would appear improbable that creatinine
originates in the body from the type of endogenous metabolism
Folin has created ; also, that, even if this were the case, it cannot
possibly be a measure of such metabolism, the deduction drawn
that, being a small and constant output, therefore only a small
and constant supply of protein in the diet to replace the nitrogen
represented by its loss is necessary must be fallacious.

It may be concluded, therefore, that, so far as the evidence
goes, the output of creatinine in the urine cannot be made use
of as evidence to support the arguments of those who consider
that the protein requirements of the body would be covered by
the presence of a very limited amount of nitrogen in the daily
food.

This finishes our summary of the recent advances that have
been recorded in the investigations into the intermediate stages
of protein metabolism. Beyond a knowledge of certain changes
that take place in proteins during the process of digestion, very
little accurate information is available. With regard to the
series of chemical reactions by which the products of tryptic
digestion are made use of by the protoplasm of the cell for its
growth, nutrition, and repair, we know practically nothing.
Still, a beginning has been made, and enough light has been shed
on some of the individual chemical reactions of the body to
enable us to look forward with hope and confidence to the
future ; otherwise, as Verworn puts it, the fact that wherever
the gross activities of the body are traced to the activity of the
individual cells, we always come upon an unsolved problem
might lead us to maintain with Bunge : "All processes in the
organism which may be explained mechanically are no more
phenomena of life than are the movements of the leaves and
branches of a tree that is shaken by the storm, or the move-
ments of the pollen that the wind wafts from the male poplar
to the female."

Amongst those things that give promise of hope in the future
are the advances that have been made in the conception of the
part played by enzyme action in metabolic processes. At present
a great variety of chemical reactions within the body are brought
about in virtue of the presence of a large group of intracellular
enzymes. In addition to the action of the digestive enzymes,
which resolve protein, carbohydrates, and fats into their com-
ponents, many oxidizing enzymes have been found in the various

THE PROTEIN ELEMENT IN NUTRITION

organs and tissues. Instances of these are met with in the
group of autolytic enzymes, which are present in the different
tissues, and which split proteins into ammo-bodies and nitro-
genous bases ; other examples are guanase of the thymus,
adrenals, and pancreas, which converts guanine to xanthine ;
adenase of the spleen, pancreas, and liver, which converts adenine
to hypoxanthine ; catalase found in many tissues, and which
decomposes peroxides — this has been looked on as the reason
why oxidation takes place only in certain tissues, and not in
others where it is not required, as, for instance, in the blood.
The extension of the conception of the work of enzymes to all
phases of metabolic activity has greatly enlarged the outlook,
and has brought within measurable bounds the time when it will
be possible to explain the causes upon which the chemical
activities of the body depend.

REFERENCES

The following works of reference, monographs, and original papers have
been consulted and freely made use of in the preparation of the foregoing
introduction.

VERWORN : General Physiology. London, 1899.

LEATHES : Problems in Animal Metabolism. London, 1906.

HILL : Recent Advances in Physiology and Bio-Chemistry. London, 1906.

HILL : Further Advances in Physiology. London, 1909.

CHITTENDEN : The Nutrition of Man. London, 1907.

SUTHERLAND : A System of Diets and Dietetics. London, 1908.

SCHAFER : Textbook of Physiology. London, 1898.

V. NOORDEN : The Physiology of Metabolism. London, 1907.

CATHCART : Protein Metabolism : Journal of Physiology, vol. xxxix., 1909.

MELLANBY : Creatine and Creatinine. Journal of Physiology, vol. xxxvi.,

1908.
LEVENE AND KRISTELLER : Factors regulating the Creatinine Output in

Man. The American Journal of Physiology, vol. xxiv., 1909.
SHAFFER : The Excretion of Creatinine and Creatine in Health and Disease.

The American Journal of Physiology, vol. xxiii., 1908.
SCHRYVER : Studies in the Chemical Dynamics of Animal Nutrition. The

Bio-Chemical Journal, vol. i., 1906.

PLIMMER : The Chemical Constitution of the Proteins, part i. London.
KRAUSE AND CRAMER : Proceedings of the Pyhsiological Society, May, 1912.

CHAPTER II
THE FOOD OF MANKIND

THE functions of food are, first, to build up the different tissues
of the body, and repair the waste of ordinary wear and tear ;
secondly, to furnish energy for the production of muscular con-
traction and other work the body has to perform, and to yield
heat for the upkeep of the body temperature.

Foodstuffs may, therefore, be considered from two points of
view — viz., their power or capability of forming new tissue and
repairing waste — this is a function of the assimilable or available
nitrogenous material ; its power of yielding energy and heat —
this is a function of all the organic elements of the food, protein,
carbohydrate, and fat. The food as taken into the body differs
very much in its chemical composition from the materials that
are utilized in carrying out the above functions, and it is by the
processes of digestion that the proximate principles of a diet are
split up and rendered easy of absorption into the blood and lymph,
and are prepared for assimilation and utilization by the several
tissues of the body.

A review of the different foodstuffs entering into the dietaries
of mankind reveals a most varied assortment, differing, under
the varying conditions of life on the earth, with the seasons,
climate, customs, races, and countries. At one extreme, as pure
animal feeders, may be taken as examples the Esquimaux and
the Indians of the Pampas ; whilst at the other extreme, as
almost pure vegetarians, may be cited many of the natives of the
tropics in the East Indies. It may be accepted, however, that
the food of the inhabitants of any particular place depends on
local circumstances, and will vary with the food materials avail-
able during the different seasons, with the cost, and with the
ease with which it can be procured. Thus the Esquimaux live
practically of necessity upon raw or partly cooked seal, walrus,

23

24 THE PROTEIN ELEMENT IN NUTRITION

and whale ; the Fuegians subsist largely on seal and porpoise ;
and the Indians of the Pampas for many months in the year
cannot obtain other food than fish.

It is generally believed that the inhabitants of the tropics, and
more particularly, perhaps, the Hindus, are practically pure
vegetarians. This is by no means the case. In India and in the
torrid zone generally the natives eat largely of cereals, fruit, and
vegetables, and many of the poorer classes cannot afford other
food ; on the other hand, where any form of animal diet is pro-
curable or can be afforded, except the flesh of animals forbidden
by religious customs, it is greedily and readily seized on and
devoured. Even amongst the so-called vegetarians of India
milk and eggs are always allowed ; many also eat fish, and some
conform their vegetarian principles to the occasional presence of
chicken or goat's flesh in their dietaries.

In a densely populated country such as India, the mass of
the inhabitants have got to live on the cheapest food procurable,
which in a country not yet thoroughly opened up is usually the
home-grown products, consisting largely of cereals, fruits, and
vegetables. They are vegetarians by force of circumstances only,
and readily avail themselves of every opportunity of increasing
their assimilable protein intake by the addition of most forms of
animal food to their diets. The craving for highly nitrogenous
food, and particularly that of an animal nature, was well brought
out during some feeding experiments on prisoners in Bengal,
when the promise of meat, or the threat of withholding it, was
quite sufficient to induce the prisoners to carry out without a
murmur whatever duties had been assigned to them. In the
less densely populated districts of Bengal, where there is not the
same necessity for the extensive cultivation of the land and pro-
duction of vegetable foodstuffs, animal food of all kinds forms
quite a fair proportion of the diet. Thus the aboriginal races
inhabiting the hills of Chota Nagpur eat all kinds of flesh,
including that of rats, jackals, snakes, lizards, and other animals.

The Hindu cannot, therefore, be accurately described as a
vegetarian by instinct. On the average, doubtless, his diet contains
considerably less animal matter than the mixed diets that are
customary in the temperate zone, but this is entirely due to his
inability to obtain the meat he craves for, and not to any subtle
promptings of Nature warning him against the evil that may
result in a torrid clime from a liberal protein dietary. The fact,
indeed, that animal food should be so much desired and, when

THE FOOD OF MANKIND 25

obtained, so greedily devoured would afford strong evidence that
certain " fundamental, instinctive, nutritional demands " have
been interfered with by the competition of a dense population,
and that the mass of the people are existing in a condition of
nitrogen starvation, and require far more assimilable protein
than their vegetable dietaries provide.

The same desire for a mixed form of alimentation is met with
in all countries and climates. Thus Major Woodruff, Surgeon,
U.S.A., writing of the inhabitants of the Philippine Islands,
says : " The natives do not eat meat because they cannot get it.
They crave it, need it, and eat it when they can." Before the
emancipation of the Japanese from the strict tenets of Buddhism,
which prohibited the taking of life under any circumstances,
even for food, fish had to be allowed, just as is the case amongst
the Buddhists in India to-day. Fish not being a prohibited
article of diet, according to Japanese ideas anything that could
be called " fish," whatever might the stretch of the imagination
required to do so, could likewise be eaten. The eating-houses in
Japan advertised mountain whale, which really meant venison ;
so venison may be eaten. The same holds true for the natives
of India, from the highest inhabitable ranges of the Himalayas
to the plains of the southern parts of Madras. Except amongst
certain narrow sects where prejudice is rampant, animal food is
partaken of freely where financial conditions do not bar the way ;
and when cost is an obstacle, it is made use of to as great extent
as can be afforded.

Mixed animal and vegetable food may therefore be looked upon
as the ordinary type of diet of the great majority of mankind,
despite the restrictions of country, climate, or race ; indeed, there
is distinct evidence of a striving after a mixed form of alimentation
in the evolution of man from the earliest geological periods
down to the present time. There can be little doubt but that
the evolution of man's diet has exerted a very marked influence
on the evolution of man himself and on his dissemination over
the face of the earth. Buckle affirms that the increasing supply
of food, " as wandering tribes advanced from the hunting to the
agricultural state, had momentous moral consequences by
diminishing dependence on mere chance, and opening the mind
to a conception of the stability of events and the laws of Nature ;
while of all physical agents by which the increase of population is
affected, food is the most active and universal. Where the
national food is cheap and abundant, population inevitably

26 THE PROTEIN ELEMENT IN NUTRITION

increases more rapidly than where it is scarce and dear."* With
regard to the function of animal food in man's evolution, Crichton-
Browne states : " In whatever direction the temper of the mind
be bent by animal or vegetable diet, it is clear that animal food
has played a decisive part in human evolution, and that the
craving for it has largely contributed to the advance of civiliza-
tion. That craving led to the invention of weapons and traps
of many kinds, to the acts of fishing and hunting, to migration,
travel, and adventure, to the patient pursuit of the taming and
domestication of wild creatures, and to provision for their wants ;
and success in the satisfaction of that craving has always been
followed by advancement alike in the arts of war and peace. A
diet rich in protein makes for physical and mental energy, and it
is not vegetable protein — always poor in amount to the bulk of
the food eaten, difficult of absorption, and probably of special
and, from a nutritive point of view, inferior constitution — but
animal protein that is required. It is animal protein that is
the true food of the brain and nerves, and hence all the more
energetic races of the world and those most distinguished for
intellectual capacity have been meat-eaters."

In connection with this most interesting subject, the brilliant
work that has been done by Dr. Harry Campbellf in adding to
our knowledge of the changes man's diet has undergone from early
times is of first importance, and demands careful consideration.

Of the three classes of the mammalia — as regards diet — the
frugivora, including such animals as the squirrel, rat, and the
monkey, are mixed feeders. Being generally more intelligent
than the herbivora, and gifted with considerable prehensile
powers, they are able to pick and choose their food, selecting it
in its more concentrated forms, such as seeds, nuts, fruits, eggs,
small birds, lizards, grubs, and the like. " Man, now essentially
a mixed feeder, belongs by virtue of his descent, as might be
expected from his high mental and bodily development, to the
frugivora."

With regard to the food of evolving man, Campbell points out
that " the products of the uncultivated vegetable kingdom are by
themselves totally inadequate to supply man's nutritive needs."
The fruits and vegetables of the present day are very different
from their wild and barely edible representatives of past ages.
They in their turn have undergone an evolution no less remark-

* Sir J. Crichton- Browne, " Parsimony in Nutrition," 1908.
f Dr. Harry Campbell, " The Evolution of Man's Diet."

THE FOOD OF MANKIND 27

able than that of man, and yet " even now no existing race of
man, in spite of the most elaborate methods of preparing and thus
increasing the nutritive value of its vegetable food, is capable of
subsisting on it alone." Animal food, prior to the period of
cibiculture, was accepted in every form procurable. Of course,
the choice would be limited to the smaller forms of animal life
until such time as evolving man learned to hunt, fish, trap, and
fashion weapons.

Three great factors influenced the changes the diet of evolving
man has undergone since presimian times. These factors were
the kind of food available ; the instinctive liking for certain kinds
of food, which depended on the richness of the food in nutrient
material, its digestibility, and its taste ; and, lastly, the ability
to secure the desired food. The food of the great apes and the
monkeys at the present time consists largely of the more concen-
trated vegetable substances, with a certain proportion of animal
food in addition. That they, like man, are descended from
ancestors whose diet was bulky, and was composed mainly of
vegetable material, is evidenced by the presence of a large caecum
and the possession of a vermiform appendix. " The diet of
primates, as of all highly intelligent animals, is a concentrated
diet, consisting of concentrated vegetable foods, and to a less
extent of the yet more highly concentrated animal foods."

Dr. Campbell goes on to trace the dietetic career of evolving
man from simian times onwards, and shows that it was character-
ized by three signal advances, each of which greatly augmented the
supply of food. He tabulates the following epochs and periods :

1. The precookery epoch — from] The simian period.

the ape stage to the invention of rThe homo-simian period,
cookery. J The early hunting period.

2. The precibicultural cookery
epoch — from the invention of
cookery to the introduction of
agriculture and the breeding of
animals for food.

3. The cibiculture epoch — from^j The period of migratory agriculture,
the time man began to produce his I The period of stationary agriculture,
food artificially to the present j (Early.)

day. J (Late.)

The homo-simian period saw the evolution of ape to man, and
his gradual spread from Southern Asia or Northern Africa over
the Indo-African continent. As intelligence increased a greater
supply of animal food was obtained, so that he became more of
a flesh-eater and less herbivorous.

THE PROTEIN ELEMENT IN NUTRITION

The early hunting period dates from the invention of weapons
and devices for hunting and fishing, such as are employed by the
representative of the precibicultural epoch at the present time.
As he passed through the homo-simian period his diet became
more and more of an animal nature, and in the hunting period
he developed largely into a carnivorous type. At this stage of
evolution, as his skill in hunting increased, man was able to dis-
seminate far and wide over the earth, as he was able to obtain
sufficient food by hunting, and from fruits and seeds.

THE PRECIBICULTURAL COOKERY EPOCH. — As soon as evolving
man began to apply artificial heat to his vegetable food, he greatly
augmented his supply, as by cooking the vegetable cellulose was
broken up, and the nutritive materials set free. The effect of
the introduction of the art of cookery was that more vegetable
food was used than in the early hunting period, until it came to
constitute one-half or more of the total diet, as is the case with
precibiculturists at the present time. Another effect was the
abandoning of, and the corresponding loss of power to digest in
the raw state, the less digestible and less palatable kinds of
vegetable foods, until he eventually limited himself to the easily-
digested kinds only. " The most primitive peoples now living
cook their food, and though widely separated both ethnologically
and geographically, they employ identical methods of cookery.
Thus the aboriginal Australians and Californians, the Bushmen,
the Andamanese, and the Ainus, all know how to extract noxious
principles from their vegetable foods, and all employ underground
ovens." The identity in the methods employed by these peoples
would show that they had taken their methods of cookery with
them when they first migrated from a common centre. All
existing precibiculturists know how to cook with underground
ovens, but some of them have not yet attained the level of dis-
covering how to boil water. Such is the case with the Australian
aborigines, the Fuegians, and the Bushmen of South Africa.

It is of importance in discussing the food of mankind to take
into consideration the food of the existing precibiculturists.
There are still many representatives of this epoch of man's
evolution — races who neither cultivate the vegetable kingdom
nor breed animals for food. Included amongst them are the
aboriginal Australians, the Andamanese, the Californian Indians,
the Esquimaux, the Bushmen of South Africa, the Veddahs of
Ceylon, and the hairy Ainus.

Their dietary consists of —

THE FOOD OF MANKIND 29

Animal Food. — Practically every species of animal is acceptable:
Worms, scorpions, moths, grasshoppers, sandflies, crickets, locusts,
centipedes, caterpillars, grubs, insects and reptiles, white ants,
frogs, toads, lizards. Big game forms the chief supply — deer,
antelope, elk, lion, and hyaena — though most of these are but
seldom procurable. The Esquimaux practically live on the seal,
walrus, and whale ; and the Fuegians on the seal and porpoise.
Fish of all kinds, salmon, shellfish, clams, etc., are all made use
of by precibicultural maritime tribes.

Vegetable Foods. — Boots : Root-digging is a most important
source of food. Small seeds : It is suggested that the recognition
of the high nutritive value of grass seeds led to the cultivation of
cereals (wheat, barley, oats, rice, maize, and millets), a step which
was in all likelihood a forerunner of civilization. Large seeds
and nuts : Acorns, sunflower, cactus, water-melon, and several
species of pine and leguminous plants. Fruits : Many varieties
of fruits and berries are eaten. Green vegetables : These are
chiefly valued for their component salt and water.

Fungi, seaweed, and gum are all made use of.

The precibiculturists store their vegetable foods. He con-
sumes a large part of it in a raw state, while cibiculturists cook
nearly all vegetable foods. No existing precibiculturist has
learned yet how to extract starch or sugar from his vegetable
food materials.

Honey forms a most important item of nutriment, except in the
case of the Esquimaux and Fuegians.

THE CIBICULTUEAL EPOCH. — " A great step forward was taken
when man began to produce food artificially, when, instead of
having to search laboriously for fruits, roots, and seeds, he took
to cultivating them ready to his hand, and when, in place of
spending long hours in the hunt which at best could yield but a
very limited supply of animal food, he learned to raise on his
own account flocks and herds of oxen, sheep, goats, and pigs, and
to breed birds of many varieties." One of the effects of the
cultivation of food has been to make man more vegetarian than
carnivorous, inasmuch as the land yields a more prolific supply
of vegetable materials than of animal.

During the migratory period of agriculture, when patches of
virgin soil were planted and abandoned for new ones as soon as
the harvest was reaped, no great advance in civilization was made.
Man still remained a hunter, combining hunting and fishing with
desultory agriculture, and he still subsisted largely on the

30 THE PROTEIN ELEMENT IN NUTRITION

products of the uncultivated vegetable kingdom. In the later
period — the period of stationary agriculture — when there was
an abundance of animal and vegetable food materials, and when
a large part of the total sum of human energy was liberated and
made available for other purposes than the quest of food, a
physiological division of labour was made possible, and social
progress made headway.

The general effects of agriculture upon man's diet have been
to accelerate the previous abandonment of raw vegetable food,
and to increase the amount of starchy foods. The concentration
of the diet, epoch by epoch, has become more and more marked,
so that at the present time it forms the outstanding feature of
the food of mankind. Another result of the development of
agriculture and the cultivation of fruits, such as the date, the fig,
the grape, and the banana, is the rapid increase in the quantity
of sugar entering into man's diet.

The conclusions Dr. Campbell arrives at from his researches on
the dietary of evolving man are —

1. The fact that man has evolved from the ape on a highly
carnivorous diet disposes of the contention that man is essentially
vegetarian by nature, and that meat and other animal foods are
harmful.

2. The fact that up to the beginning of the agricultural period
man's supply of sugar was scanty, whereas during it, and especially
within recent times, it has been enormously increased, suggests
that ill-health may often result from its excessive use. As a
matter of experience in the dieting of patients, more good can be
done by curtailing the starchy foods and sugar than by cutting
down animal food, and this even in such diseases as gout and
megrim.

3. So far as the general results affect the food of mankind,
the ideal dietary is one that is simple in quality and moderate in
quantity. It should contain a fair proportion, a quarter to one-
third, of animal food. A certain amount of vegetable food
should be uncooked in order to compel thorough mastication,
and excess of sugar should be guarded against.

The general bearing of Dr. Campbell's work on the foodstuffs
and diet of evolving man would be to show how very important
a part has been played by the protein element. The food of
existing precibiculturists is estimated as being composed of half
animal and half vegetable material, so that the degree of nitrog-
enous interchange within the body should reach a high level.

THE FOOD OF MANKIND 3J

Animal food, as contrasted with the types of vegetable foods
available in those places where precibiculturists at present are to
be found, is of far greater nutritive value. From experiments
carried out in India, it will be shown that even with cultivated
vegetable foodstuffs (barley, millets, etc.) the coefficient of
protein absorption rarely reaches 60 per cent., while with animal
food it is over 95 per cent. Even in the presimian period of
man's evolution there would appear to have been a continuous
struggle for the more concentrated forms of protein food, and
particularly for the highly nitrogenous animal materials.

THE CHEMICAL COMPOSITION OF FOOD MATEEIALS.

It is necessary in making a general survey of the food of man-
kind to take notice of the gross chemical composition of the
different food materials. Analyses of practically every form of
food have been made — at least for those entering into the dietaries
in use in Europe and America. A very complete account of the
work done in America will be found in Atwater and Bryant's
" Chemical Composition of American Food Materials," Bulletin
No. 28, U.S. Department of Agriculture. It will, therefore, only
be necessary to refer to the chemical composition of some of the
chief foodstuffs of European or American origin, whilst a full
account of the composition of those peculiar to India and the
tropics generally will be given, as the results hitherto obtained
for these substances have not been widely circulated.

Accepting the ordinary classification of the organic chemical
compounds or proximate principles of food materials as being
conveniently grouped under the headings of protein, carbo-
hydrate, and fats, it may be stated in very general terms, with
regard to the protein element, that animal food shows from 20 to
25 per cent., legumes of different types almost an equal amount,
cereals from 7 to 15 per cent., vegetables from 1 to 3 per cent.,
fruits about the same as vegetables, and nuts from 10 to 20 per
cent. In the case of animal food the percentage of protein varies
with the condition of the flesh and with the presence or absence
of fat.

The first table on p. 32 gives the chemical composition of
some of the chief European and American foods, the analyses
being those of Atwater and Bryant.

In the second table are given the results of analyses of Indian
foodstuffs ; these analyses were made in India from samples of
the food materials in use in the gaols of Bengal and the United

32

THE PROTEIN ELEMENT IN NUTRITION

Food Materials.

Water.

Protein.

Fat.

Carbo-
hydrates.

Ash.

Fuel Value
per Pound.

Beef, fresh : Brisket,

Per Cent.

Per Cent.

Per Cent.

Per Cent.

Per

Cent.

Calories.

medium fat

54-6

15-8

28-5

—

0-9

1,495

Ribs, lean

73-1

19-5

8-3

—

1-0

715

,, fat ..

52-0

16-5

31-1

—

0-8

1,620

Tongue

70-8

18-9

9-2

—

1-0

740

Lamb, fresh : Hind-

quarter

60-9

19-6

19-1

—

1-0

1,170

Mutton, fresh : Shoul-

der, medium fat . .

61-9

17-7

19-9

—

0-9

1,170

Pork, fresh : Ham,

fresh

50-1

15-7

33-4

—

0-9

1,700

Bacon, smoked,

average

20-2

10-5

64-8

5-1

2,930

Sausage, Pork, aver-

age

39-8

13-0

44-2

1-1

2-2

2,125

Chicken

74-8

21-5

2-5

—

1-1

505

Trout

77-8

19-2

2-1

—

1-2

445

Eggs

73-7

13-4

10-5

—

1-0

720

Butter

11-0

1-0

85-0

—

3-0

3,605

Cheese, Cheddar ..

27-4

27-7

36-8

4-1

4-0

2,145

Wheat flour, fine . .

13-8

7-9

1-4

76-4

0-5

,625

entire wheat . .

11-4

13-8

1-9

71-9

1-0

,675

Rice

12-3

8-0

0-3

79-0

0-4

,630

Barley-meal

11-9

10-5

2-2

72-8

2-6

,640

Oatmeal

7-3

16-1

7-2

67-5

1-9

,860

Kafir corn

16-8

6-6

3-8

70-6

2-2

,595

Rye flour

11-4

6-8

0-9

78-8

0-7

1,630

Carrots, fresh

88-2

M

0-4

9-3

1-0

210

Cauliflower

92-3

1-8

0-5

4-7

0-7

140

Peas, green

74-6

7-0

0-5

16-9

1-0

465

,, dried

9-5

24-6

1-0

62-0

2-9

1,655

Potatoes, raw

78-3

2-2

0-1

18-4

1-0

385

Bananas, yellow

75-3

1-3

0-6

22-0

0-8

460

Almonds

4-8

21-0

54-9

17-3

2-0

3,030

Walnuts

2-5

18-4

64-4

13-0

1-7

3,300

Food Materials.

Water.

Protein.

Carbo-
hydrates.

Fat.

Ash.

Per Cent.

Per Cent.

Per Cent.

Per Cent.

Per Cent.

Goat's flesh

—

24-06

.

2-50

1*10

Fish

—

17-80

—

5-04

—

Rice, Burma

11-13

6-95

77-25

0-96

1-34

country

11-05

6-62

81-07

0-50

1-04

Wheat flour

11-83

11-47

70-90

2-04

3-14

Maize (corn -meal)

11-50

9-52

68-90

4-44

3-75

Barley

—

8-92

76-10

1-90

—

Juar (a small millet)

—

7-67

67-26

2-77

—

Bajra (a large millet)

—

8-72

73-40

4-76

—

Mung dal (a legume)

10-87

23-62

53-45

2-69

3-57

Massur dal , ,

10-23

25-47

55-03

3-00

3-33

Gram dal

10-07

19-91

54-22

4-34

4-69

Kalaidal

10-87

22-58

58-02

MO

3-61

Mattar dal

10-96

22-01

53-97

1-96

3-60

Arhar dal

10-08

21-70

54-06

2-50

5-50

Uriddal

—

22-33

55-22

1-95

—

THE FOOD OF MANKIND

33

Provinces of Agra and Oudh. Only averages of the chemical
composition are shown ; full details will be found in the original
papers.*

These results are the averages of a very large number of analyses
carried out at different seasons of the year, during which the
degree of moisture varies considerably.

Professor F. G. Benedict, of the Nutrition Laboratory of the
Carnegie Institution of Washington, U.S.A., very kindly assisted
in the examination of the Indian food materials. A tabular
statement of the averages of his results for the moisture and the
heat of combustion is appended :

Food Materials.

Water.

Heat of Combus-
tion : Calories
per Gramme.

Number of
Determina-
tions.

Wheat .. .

10-58

3-951

14

Maize

9-97

4-094

4

Rice, Burma

10-27

3-820

4

,, country

10-75

3-805

4

Barley .. .

13-47

3-752

4

Juar

11-13

3-913

2

Arhar dal

9-81

4-053

10

Gram dal . .

9-62

4-218

14

Kalai dal

10-19

4-034

4

Mattar dal . .

9-76

4-075

4

Massur dal

9-92

3-060

6

Mung dal

9-80

4>051

2

Urid dal . .

10-56

3-976

4

The moisture was determined by prolonged desiccation
in a high vacuum, according to the method of Benedict and
Manning. The heat of combustion was determined in a Kroker's
calorimetric bomb by means of a new form of adiabatic calori-
meter, designed by Benedict and Higgins. The hydrothermal
equivalent to the calorimeter system was so taken that the heat
of combustion of pure cane-sugar was 3,959 calories per gramme.

THE DIGESTIBILITY AND ABSORBABILITY OF FOODSTUFFS.

The food of mankind may now be considered from the stand-
point of its real value — i.e., the amount of the food ingested that is
actually taken up and made available for the requirements of the
body. It is a mere truism to state that the gross chemical value
of a food material may not necessarily be a measure of its real
nutritive value, and that the real value depends on the degree of
absorbability of its proximate principles ; yet in many cases

* Scientific Memoirs, Government of India, Nos. 34, 37, and 48.

34 THE PROTEIN ELEMENT IN NUTRITION

dietaries are framed on the results of chemical analyses alone, and
little or no account taken of the absorption possible from the
different foodstuffs. This may not be a matter of first import-
ance when dealing with the high-class food materials made use
of in Europe and America, or where an animal protein forms a
substantial part of the nitrogenous intake, but it is of very real
importance in the dieting of bodies of men with the vegetable
foodstuffs of India and the tropics generally. Many of the
dietaries framed for prisoners, famine camps, soldiers, etc., in
India have been worked out from the gross chemical composition,

ABSORBABILITY OF DIFFERENT FOODS.

Food Materials.

Per Cent. Absorbed.

Dry

Substance.

Protein.

Fat.

Carbohydrates.

Meat and fish

95

Practically all 79 to 92

ST.:

95
91

,, " 96
88 to 100 93 to 98

7

Butter

98

—

Margarine

96

—

Fine wheat bread . .

95£

81 to 100 ?

99

Decorticated whole

wheat bread

88

69J

J

92£

Maize meal

93

89

I

97

Macaroni

95

81

?

97^

Rice ..

96

84

?

99

Peas ..

99

82A

j

96i

Beans

82

70

—

I

French beans

85

—

—

—

Potato puree (in small

quantities)

—

80£

—

Practically all

Potatoes in general

80i

70

—

92£

Cabbage . . . . 85

814

—

84£

Carrots .. .. 79

—

82

Beetroots

—

72

?

82

so as to reach a certain standard, whilst no allowance was made
for the fact that the absorption of the most important element,
protein, from Indian vegetable food materials may be, and
is in the majority of cases, very poor indeed. It is therefore of
the greatest importance to know what the relative absorption is
from the different types of foodstuffs in order that a clear
conception may be formed of the real nutritive value of a food,
and that in arranging dietaries they may be framed on their real
worth, and not merely on their gross or apparent value.

Within comparatively recent years a great deal of work has
been done in Europe and America with a view of ascertaining the

THE FOOD OF MANKIND

35

coefficients of absorbability of the several constituents of the
different foodstuffs. A great part of our knowledge on this
subject is due to the admirable work done in the different nutrition
laboratories in America in connection with the U.S. Department
of Agriculture. Hutchison * summarizes the results in the table
on p. 34, constructed from the figures of B-ubner and Atwater.

From a large number of experiments on man, Langworthy f
calculates that on an average the different groups into which
foods may for convenience be divided have the following co-
efficients of digestibility :

COEFFICIENTS OF DIGESTIBILITY OF DIFFERENT GROUPS — PERCENTAGES.

Protein.

Fat.

Carbo-
hydrates.

Animal food

97

95

98

Cereals

85

90

98

Legumes, dried . .

78

90

97

Starches and sugars

—

—

98

Vegetables

83

90

95

Fruits

85

90

90

Vegetable foods . .

84

90

97

Total food

92

95

97

These figures show that the protein and fat of animal foods
are much more completely absorbed than those of vegetables,
with which there may be a loss in the f seces up to over 30 per cent,
of the total protein consumed.

On the whole, however, it may be accepted that the foodstuffs
in use in Europe and America show a high percentage of absorp-
tion for the several proximate principles. Animal protein is
readily and completely digested, that of vegetables less com-
pletely. Fats are well digested, and carbohydrates show a high
coefficient of absorbability, except when the amount of crude
fibre or cellulose is large.

On a fruitarian diet the digestibility is not quite so good.

Jaffa gives the following results based on thirty digestion
experiments with fruit dietaries :

Protein

75

per cent.

absorbed.

Fat

. . .

86

l(

M

Sugar

.

95

n

Fibre

. .

79

ti

Calories

86

"

"

* Hutchison, " Food and the Principles of Dietetics," 1911.

f Langworthy, Circular No. 46, U.S. Department of Agriculture.

CHAPTER III
TROPICAL FOOD MATERIALS AND THEIR DIGESTIBILITY

WHILE the digestibility of the different food materials entering
into the composition of European and American dietaries has
been very thoroughly worked out, up to quite recently no
data were available for computing the true nutritive values
of many of the vegetable foods of India and the tropics. A
considerable amount of experimental work has been carried out
during the last few years in determining the protein and carbo-
hydrate absorption of the different classes of vegetable food
materials peculiar to tropical countries.* It is necessary in a
review of the digestibility of the foods of mankind to take into
consideration the results arrived at, and contrast them with the
values found for the absorption of protein from similar types of
food materials made use of in other countries, as set forth in the
previous chapter.

The common foodstuffs of India and the tropics generally are
mostly derived from the vegetable kingdom. Some are peculiar
to the tropics, being rarely seen in Europe ; others are peculiarly
tropical foods in that the quantities entering into the dietaries
are very great, being out of all proportion to what would be
consumed of the same food material by Europeans or Americans.
These foodstuffs include rice, maize, wheat, barley, different
millets, different legumes, vegetables, and fruits.

Eice, maize, wheat, and barley have been investigated, and
the coefficients of absorption worked out, as shown in the above
tables ; but in dealing with the same food materials in India the
local methods of preparing the grains for food have to be taken
into consideration. These methods are rough and ready, and
the resulting products are very dissimilar to the high-class prep-
arations placed on the market in Europe. The ordinary method

* Scientific Memoirs, Government of India, Nos. 37 and 48.
36

TROPICAL FOOD MATERIALS 37

of employing the cereals and legumes as food consists in separating
the grain from the chaff and dirt, often very imperfectly ; they
are then washed, sun-dried, and ground between millstones into
meal. The great mass of the population live, therefore, on a
wholemeal dietary ; in certain cases, however, some of the
finer material is sifted out, and made use of in confectionery.
In the larger towns and amongst the wealthier classes finer
grades of flour prepared in properly equipped mills are made
use of.

Rice forms the staple food of the great majority of the popula-
tion of Lower Bengal, Eastern Bengal, and Assam, Burma, and
the different parts of India where there is a sufficient supply of
water for its cultivation. The rice in use is of two kinds — Burma
rice and country rice. Burma, or Rangoon rice, the so-called
" white " rice, is prepared direct from unhusked " paddy " —
i.e., as obtained from the rice-fields ; it is milled by machinery,
and the husk, pericarp, and surface layers of the seed are removed.
The result is a clean white rice grain, deprived to some extent of
its outer layers, and slightly of its protein and mineral con-
stituents.

Indian, or country rice is prepared by soaking the " paddy "
for from twenty-four to forty- eight hours in water ; it is then
transferred to lightly covered cylinders, in which it is steamed
for from five to ten minutes ; subsequently it is removed to open
paved — usually sun-baked mud — courts, and dried by exposure
to the sun. The sample obtained by this process is yellowish-
brown in colour, and usually much contaminated with dirt. The
outer layers of the grain, however, are not lost, so that, weight
for weight, it should contain more protein and mineral matter
than Burma rice.

Rice is the poorest of all cereals in protein ; when cooked it
swells up, and absorbs about three to three and a half times its
weight of water. Very little of the protein is removed when it
is boiled in a large quantity of water and the excess strained off.
From analyses of the drained material there appears to be a loss
of about 0-20 per cent, of the protein.

Being very deficient in the protein element, it will be obvious
that, in order to obtain an adequate supply of this important
material, a people whose diet consists almost wholly of rice must
consume large quantities. This is found to be the case, and in
all fixed dietaries where rice is the main constituent it is present

38 THE PROTEIN ELEMENT IN NUTRITION

in quantities up to and exceeding 26 ounces of the dried material.
When it is borne in mind that rice swells up on being cooked to
almost five times its dried bulk, it will be readily understood
how voluminous a diet rice provides. It has been calculated that
the gaol diet of Lower Bengal attains such a bulk on being cooked
that an ordinary sized stomach would be required to be filled to
the extreme limits of its capacity three times a day in order to
accommodate the total amount. According to Hutchison, the
total capacity of an ordinary sized European stomach is about
1,200 grammes, while the weight of a full gaol diet of rice exceeds
3,000 to 3,500 grammes.

Continental and American observers state that rice is absorbed
with very great completeness in the intestine, while its progress
through the stomach is slow. Thus Hutchison states that practi-
cally none of the starch is lost, but the waste of protein amounts
to 19 per cent. Rubner and Atwater place the protein absorption
at 84 per cent. Oshima,* in his digest of Japanese investigations,
gives the average absorption of the protein of rice as 75-6 per
cent., and of rice gruel as 56-1 per cent. These results, however,
were obtained in the majority of cases when rice was eaten in
comparatively small quantities. When the quantity of rice in
the diet is large, the digestibility and protein absorption from it
falls, and from the results of investigation on prisoners in India
there is strong evidence that the protein absorption from rice, or
from diets containing rice, varies largely with the actual volume
or bulkiness of the diet.

In diet scales in Europe and America the question of bulk is
not one of much importance ; the diets are very much concen-
trated, and are never sufficiently voluminous to cause distension
of the stomach, while the contrary is commonly the condition
met with when large quantities of rice are consumed. This
question of bulk is a very important one from the standpoint of
the absorption of protein. It was found in feeding experiments
on prisoners in Bengal that when a diet was bulky out of all
proportion to the nutriment it contained, the absorption of
protein was greatly interfered with, and that by decreasing or
increasing the quantity of rice in the diet, an increased or de-
creased absorption of protein takes place — i.e., under certain
conditions a decrease in the bulk of a diet will cause not only an

* Oshima, " A Digest of Japanese Investigations on the Nutrition of Man,"
U.S. Department of Agriculture, Bulletin No. 159.

TROPICAL FOOD MATERIALS 39

increased percentage absorption of protein, but also an increase
in the total amount of protein undergoing metabolism. The
following results * of observations on this point will make the
meaning clear :

In diets containing 30 ozs. of dry rice 6-55 grms. nitrogen were absorbed.
26 7-55

24
23
20
19

8-00
8-09
8-40

8-47

The explanation of a decrease in the amount of nitrogenous
interchange, as the bulk of a diet increases beyond a certain
point, is in all probability due to the difficulty experienced by the
digestive juices in penetrating the mass, and to dilatation and
weakening of the walls of the stomach, inducing a loss of power
in the passing on of its contents. Perhaps even more important
is the fact that the large mass on reaching the intestines sets up
increased peristalsis, so that the contents are hurried on into the
large intestine, where protein absorption is at a minimum. The
large watery or semi-solid stools passed by prisoners fed on large
quantities of rice would lend support to this view.

It will be obvious from what has been said that where bulk
interferes with the protein absorption from a diet no fixed co-
efficient for the absorption of the protein of its constituents can
be possible. For each separate quantity of rice above a certain
amount a different percentage of its contained protein will be
absorbed. This was found to be the explanation of the results
obtained for the variations in the percentage of protein absorp-
tion met with in the bulky diets of prisoners in the gaols of
Bengal, and in all probability it would assist in explaining the
varying coefficients of the digestibility of rice given by other
observers. In Oshima's list the protein absorption of rice ranged
in different experiments from 46-5 to 864 per cent. Aron con-
firms the results obtained for the protein absorption of rice.
His figures vary from 53 to 68 per cent.f

The decrease in the coefficient of protein absorption with diets
containing large amounts of rice may be so great that the total
nitrogenous absorption may fall to little more than 50 per cent,
of the protein presented in the diet. Thus, on an average, over
a large number of experiments on batches of prisoners under

* Scientific Memoirs, Government of India, No. 37, Chart I.

f Aron and-Hocson, " Rice as Food," Philippine Journal of Science, 1911,

40

THE PROTEIN ELEMENT IN NUTRITION

observation for varying periods of from five to ten days, the
percentage of protein absorption from diets containing about
26 ounces of rice — the other constituents being contant — works
out to be 54-28 per cent. As the quantity of rice was reduced—
the other constituents of the dietary remaining constant — the
percentage absorption of protein gradually rose,* thus —

Diet containing 32 ozs. of rice showed 6-55 grins
26 7-85

24
23
20
19

8-00
8-09
8-40

8-47

N. absorption, or 45-76 %
53-66 ,
55-39 ,
59-69 ,
64-03 ,
68-33 ,

There can be little doubt that with diets in which rice forms only
a small element, in an otherwise non-bulky diet, the percentage
absorption of the protein of rice would be comparatively high,
probably up to the figure given by Atwater — viz., 84 per cent.

But not only does the great bulk of rice when cooked cause
interference with the protein absorption from the rice itself, but
it also causes the nitrogenous element of the other constituents
of the diet to be less readily absorbed. The same explanation
given for the relatively poor absorption of the protein of rice in
a bulky diet would hold for any other constituents — the whole
mass in the stomach having little opportunity of being thoroughly
mixed with gastric juice, and, after leaving the stomach, being
hurried on past the parts where absorption is best carried out into
the large intestine, where absorption is at a minimum. As an
illustration of the influence of the volume of diets on the absorp-
tion of the protein of its component, the results f obtained in
feeding a batch of prisoners for a week on each of the following
diets may be cited :

Constanta.

Varying
Amounts of

Absorption of
Nitrogen per

Per Cent, of
Nitrogen

Diet.

Rice.

Man Daily.

Absorbed.

(16 ozs.

9-71 grms.

56-96

I.

Wheat . . 10 ozs. }

14 „

10-10 „

61-52

II.

Arhardal.. 6 ,, \ +

12

10-49 ,,

66-45

III.

Vegetables 6 ,, J

w ;;

8 „

9-86 ,,
9-78 „

64-95
67-23

IV.
V.

From these results it is evident that a decrease in the amount
of rice from 16 to 12 ounces causes both a relative and actual

* Scientific Memoirs, Government of India, No. 37, p. 61.
f Ibid., No. 37, Chart VIII., p. 132,

TROPICAL FOOD MATERIALS 41

increase in the amount of protein undergoing metabolism ; also,
when Diets III. and IV., or IV. and V., are contrasted, the fact
that there must be an accompanying increased absorption from
the " constants " of the diets will be clear. Thus —

Diet III. N. of constants+ 3'74 grms. N. from rice, 10-49 grms. absorbed,
„ IV. „ „ +3-12 ,, „ 9-86 „

which would mean, if the increase of nitrogen absorption all came
from the extra rice in Diet III., that 0-62 gramme gave an
absorption of 0-63 gramme. This is impossible, and the explana-
tion simply is that there is a greater amount of protein absorbed
from the " constants " and from the rice when the bulk of
the diet is decreased. A similar comparison of Diets IV. and
V. exemplified this also.

If the Diets I., II., and III. be examined, it will be found
that where the amount of rice is beyond the optimum, in this
combination, 12 ounces, the reverse conditions obtain. As the
rice increases in quantity, and the bulk of the diet becomes
greater, a lower and lower percentage of protein absorption takes
place from both " constants," and from the varying quantities of
rice.

These results serve to illustrate the impossibility of obtaining
any fixed figures for the coefficients of the protein absorption of
rice, or other foodstuffs of a bulky nature, when the quantities
of the food materials entering into the composition of the
dietaries are large. Under such conditions they also show that
when a bulky food, such as rice, is combined with other materials,
not in themselves bulky, the degree of protein absorption from
both the rice and the other foodstuffs varies inversely with the
total volume of the diet.

It is quite different when food materials of a more concentrated
nature are experimented with, and when bulk does not cause any
interference with protein absorption.

In connection with the poor protein absorption obtained from
vegetable dietaries, Hutchison, quoting Hofman, states that in a
number of prison diets of an exclusively vegetable nature, it was
found that on an average from 25 to 47 per cent, of the protein
escaped absorption — results that are very much the same as
those obtained in investigating the nutritive values of the
vegetable gaol dietaries of Bengal.

Hutchison has collected the results of a number of experiments

42 THE PROTEIN ELEMENT IN NUTRITION

on the absorption of protein with vegetable foods, contrasting
them with that of the protein of meat :

RELATIVE ABSORPTION OF PROTEIN IN VARIOUS FOODS.

Diet. Protein not Absorbed.

Meat 2-3 per cent.

Lentil flour 10-5

Dried peas 17-0

Beans ) OA.O
Flour / ' '

Potatoes 32-0

Carrots and fat 39-0

Lentils (simply soaked and boiled till soft) . . 40-0

In dealing with the other cereals utilized in India as food, no
great difficulty was experienced in obtaining fairly constant
figures for the coefficients of protein absorption, as, except in
the case of rice, the question of bulk is not a serious one. On
the other hand, the ordinary foodstuffs are very much mixed with
one another, and often greatly contaminated with foreign grains,
so that pure samples are difficult to obtain. The effect of this
is that variations in the figures representing the nitrogen absorp-
tion are met with, unless the same sample is used throughout the
experiments.

Wheat is by far the most important of the cereals used as food
in India. It is prepared for consumption by grinding with small
hand-driven grinding-stones, the whole grain being so treated.
The bran is partially got rid of by sifting, but the germ remains,
the meal, or ata, consisting of the products of the germ and
endosperm. The wheat is always freshly ground every few days,
so that there is no difficulty over the oil in the germ turning
rancid. The ata, or meal, which contains the products of the
whole wheat grain except the coarser elements of the bran, is
baked with water and salt into unleavened bread, usually in the
form of flat cakes, called chapatti or roti. A mixture of
wheaten and barley flour is employed in some districts for making
the chapatti, but in the majority of cases the wheat crop is
grown contaminated, particularly with barley, so that pure
samples of wheat are difficult to obtain. In the poorer samples
of wheat all manner of grains are to be found — barley, gram,
maize, linseed, etc. ; some of these will tend to raise the protein
content of the sample, while decreasing its coefficient of protein
absorption, while some will tend to lower the protein content and
relative absorption at the same time. In the case of fairly clean

TROPICAL FOOD MATERIALS 43

samples, however, the contamination is mainly due to barley, so
that the tendency is for a fall in the protein content to be accom-
panied by a fall in the percentage of nitrogen absorbed. Thus,
in contrasting some of the results obtained for the protein content
and protein absorption of different samples of wheat, it was
found that —

1 oz. first class Benares wheat contains 0-5354 grm. N., of which 80-5 per

cent, is absorbed.
1 oz. first class Agra wheat contains 04896 grm. N., of which 72-3 per cent.

is absorbed.
1 oz. ordinary Naini wheat contains 0-4710 grm. N., of which 68-8 per cent, is

absorbed.
1 oz. ordinary Benares and Lucknow wheat contains 0-4630 grm. N., of which

69-2 per cent, is absorbed.

It would appear from these findings that a relationship exists
between the protein content of a sample and the percentage of
protein absorption from that sample. While this may be true
for samples that are fairly clean and pure, or in which the only
or chief foreign element is barley, it does not hold good for all
classes of wheat, nor when the containing factors are of various
kinds. Thus —

1 oz. ordinary Agra wheat contains 0-4536 grm. N., of which 63-3 per cent.

is absorbed.
1 oz. ordinary Lucknow wheat contains 0-4360 grm. N., of which 67-5 per cent.

is absorbed.
1 oz. ordinary Lucknow wheat contains 0-4415 grm. N., of which 71-4 per cent.

is absorbed.

So that, although the ordinary sample of Agra wheat contains a
higher percentage of nitrogen than either of the Lucknow samples,
yet it is accompanied by a percentage of protein absorption
considerably lower than was found in the case of the latter.

It may be accepted, therefore, that in India, while really good,
clean wheat shows a protein absorption of over 80 per cent., thus
comparing very favourably with the results given by European
and American authorities, the ordinary contaminated material
available to the great mass of the population is not nearly so
well absorbed, the coefficient of protein digestibility varying in
different samples from 62-8 to 72-3 per cent.

Experimenting in India on batches of from five to ten prisoners
kept under observation for periods varying from five to ten days,
it was found that the absorption of the protein of good wheat
varied within narrow limits.

The following results were obtained :

44 THE PROTEIN ELEMENT IN NUTRITION

Observations * Nos. 21 and 22 . . 80-8 per cent, of nitrogen absorbed.

,, 23 „ 24 .. 804

Observation No. 28 .. .. 79-3

,,30 .. .. 81-0

,,32 .. .. 80-8

The average absorption of the protein of this wheat is, there-
fore, practically 80-5 per cent. These results were all obtained
from the same sample of wheat. The wheat was specially selected
as being clean and pure for the purpose of the experiment. It
was ground in hand-driven stone-mills, and contained all the
elements of the grain, except the coarser parts of the bran, which
were rejected on sifting. An absorption of over 80 per cent, of
the protein of all the elements of the wheat grain, including the
germ, therefore, may be expected when the sample of wheat is
pure and in good condition.

But no such favourable results are obtained when the sample
of wheat is contaminated and dirty. From the results of
observations carried out on a large scale in four large gaols of
the United Provinces, the protein absorption, shown by the
different wheats experimented with, was found to vary with
the condition of the sample. Taking an average of the results
given by feeding experiments with ordinary wheat as supplied, the
protein absorption works out as follows :

Observations-f Nos. 25 and 26. . . . 69-3 per cent, absorbed.

Observation No. 31 68-3

Observations Nos. 51, 52, and 53 . . 62-8

,,57, 58, and 59 . . 69-7

„ 60 and 61 .. . . 67-9

„ 63, 64, and 65 . . 71-4

Observation No. 72 67-5

,,84 72-3

Observations Nos. 77, 78, and 79 . . 63-1

That is, taking the protein absorption, where different samples
of common wheat were experimented with, the average quantity
made use of in the body works out at 68 per cent.

For the very large proportion of the wheat consumed by the
masses in India, this percentage of protein absorption is all that
could be counted on. It is not altogether a matter of adultera-
tion by the seller, as not infrequently a mixture of cereals,
such as wheat and barley, is cultivated as such. The majority
of the population live by agriculture, and grow their own food-
stuffs, which are ground and prepared by the women- folk in their
own homes. Except in the large towns, there is practically no
buying of ground wheat or other foodstuffs.

* Scientific Memoirs, Government of India, No. 48. f Loc. cit.

TROPICAL FOOD MATERIALS

45

So far as information is available, there are practically no
results of experimental work recorded where the whole grain of
the wheat is utilized. Goodfellow, in investigating the nutritive
value of Hovis bread — in which the germ is partially cooked with
superheated steam, ground to meal, and added to the ordinary
flour — found the percentage of protein absorption very little
lower than with ordinary white bread. It is important, there-
fore, to remember that when dealing with a good quality of wheat,
the protein absorption from the flour containing all the elements
of the grain, except the coarser parts of the bran, is slightly over
80 per cent., and, further, that the protein content of the wheat
has not been impoverished by the exclusion of the highly nitrog-
enous germ. In the particular sample of wheat referred to, and
with which the above result was obtained, the amount of protein
present was 12 per cent.

It is necessary now to examine the effect of the modern methods
of milling wheat on the protein content of the products obtained.

Hutchison gives the composition of the different parts of a
wheat grain as follows :

Bran:
13-5 per Cent.

Endosperm :
85 per Cent.

Germ:
1 '5 per Cent.

Whole Grain :
100 per Cent.

Water

12-5

13-0

12-5

14-5

Nitrogenous matter . .

164

10-5

35-7

11-0

Fat

3-5

0-8

13-1

1-2

Starch and sugar

43-6

74-3

31-2

69-0

Cellulose

18-0

0-7

1-8

2-6

Mineral water

6-0

0-7

5-7

1-7

In the old method of stone- grinding — the method still in use
in India — the bran was removed, but not the germ; whereas in the
modern steel-roller milling both bran and germ are excluded.
After being ground, the products are separated into different
portions by sifting, and the portion that constitutes flour is
derived entirely from the endosperm, and forms from 70 to 73 per
cent, of the whole grain. This flour is further separated into a
portion derived from the central part of the endosperm, which
is poor in protein and rich in starch. This is termed " patents " ;
the remaining portion is the ordinary household or baker's
flour. Neglecting further refinements in the division of the
products, the effect of modern methods of milling is to lessen
very considerably the protein and mineral constituents of

46

THE PROTEIN ELEMENT IN NUTRITION

the flour. Thus Hutchison compares the different preparations
as follows :

Wheat-meal.

Medium Flour:
Households or
Baker's.

Finest Flour :
Patents.

Nitrogenous matter
Fat
Carbohydrates

Ash

14-2 per cent.
1-9
70-6
1-2

10'7 per cent.
M
75-4
0-5

7'9 per cent.
1-4
76-4
0-5

There are factors, however, which tend to counteract this loss
of protein : thus the very whitest flour — " patents " — is generally
used for fancy bread and pastry ; the ordinary flour is a blend of
different wheats selected as the most suitable for bread-making.
The suitability depends on " strength," which in its turn depends
on the percentage of gluten ; so that the protein element can never
fall very low, otherwise the flour would not make bread at all.
Again, according to some authorities, the protein content of
different wheats varies enormously,* so that the exclusion of the
germ would make little difference in comparison with the differ-
ence between flour made from different varieties of wheat.

Quite recently an outcry has arisen against the composition of
the fine white bread at present placed on the market, and a demand
made for the improvement of the finer high-grade flours, particu-
larly in their nitrogenous and mineral constituents. As already
pointed out, with the present processes of milling about 70 per
cent, of the wheat grain is utilized as flour. In the improvement
advocated a standard bread was demanded, the proposal being
that not less than 80 per cent, of the grain should be made use of
in the manufacture of flour, and that this should contain the germ
of the wheat grain and the semolina.

The advantages claimed for "standard" bread are — It contains
a higher proportion of iron and phosphorus in a state of com-
bination capable of absorption ; other mineral constituents are
also higher, which is a point of great importance in the formation
of bone and teeth. It has not been impoverished by the loss of
the germ and part of the outer layers, so that it contains a higher
percentage of protein and fat than white bread. The presence
of a small portion of the bran acts as a mechanical stimulus to
the digestive tract, thus lessening the tendency to constipa-

* No great differences in the protein content of wheat were met with in the
analyses of various samples made in India. The results obtained were fairly
uniform, so long as clean, pure wheat was examined.

TROPICAL FOOD MATERIALS 47

tion. Certain other advantages of minor importance are also
claimed.

There is very little doubt of the truth of these claims for the
superiority of " standard " flour when contrasted with white
flour manufactured from the same class of wheat, and with the
same care in mixing wheats from different sources, as millers
state is the custom at present in order to obtain a strong flour,
it is difficult to see how this " standard " flour would not maintain
its superiority. In other words, under the same conditions of
manufacturing, " standard " flour should show the above-men-
tioned points of superiority when contrasted with the ordinary
white flour milled from the same source. A " standard " flour
obtained from a low-class wheat might in all probability be
inferior in nutritive value to ordinary white flour milled from a
high- class wheat, and it has been asserted that the " standard "
flour allows millers to make use of inferior and injurious wheats,
which could not be utilized in the preparation of good white flour.
The report, however, of the medical department of the Local
Government Board * on the bleaching of flours would show that
millers can and do make use of inferior wheats in the production
of white flour ; the dark or injured parts can be bleached to
represent the finest flour of high-grade wheat. The report states
that bleaching with nitrogen peroxide, carefully carried out, in itself
produces no appreciable effect upon the baking qualities of flour,
but it is capable of improving the colour, and therefore the com-
mercial value, of the lower grades of flour, enabling a low-priced
article to simulate the appearance of a high-priced one. The
reportf goes on to show that the alterations in, and the additions
to, flour which result from a high degree of bleaching by nitrogen
peroxide cannot be regarded as free from risk to the consumer.
It is demonstrated that there is a certain amount of nitrite-
reacting material present in bleached flour, one of the effects of
which is to cause interference with digestion. Thus, Halliburton
found that traces of nitrites exert a distinct inhibitory effect on
both proteolytic and amylolytic enzymes, 1 part of sodium
nitrite in 8,000 inhibiting peptic digestion entirely, while 1 part
in 32,000 decreased the power of the enzymes to one-seventh of
its normal activity ; similar results were obtained in the case of
the salivary digestion of starch. Hale has found that sodium

* Reports to the Local Government Board on Public Health and Medical
Subjects, Nos. 46 and 47.

f " The Purity of Flour and Bread," British Medical Journal, vol. i., 1911.

48 THE PROTEIN ELEMENT IN NUTRITION

nitrite in a dilution of 1 part in 5,000 to 200,000 has a distinct
inhibiting action on gastric digestion. Harden also showed a
distinct, though small, inhibition in the peptic digestion of samples
of bleached flour as compared with unbleached.

Another method by which the millers are able to make use of
inferior wheats in the production of the finest white flours is by
the addition of " improvers." These were found to consist
essentially of phosphoric acid, or acid phosphates of calcium,
magnesium, potassium, phosphorus trichloride, and penta-
chloride, oxides and sulphides of phosphorus, acids such as
iodic, hydrofluoric, formic, acetic, propionic, etc., alcohol,
aldehyde, and ketones. The claim for these is that more bread
can be obtained per sack of flour by their use, which simply means
that more water can be supplied to the consumer at the price of
bread. The protein content of flour is an important matter from
the standpoint of nutrition, especially where bread enters largely
into the diet. Flour from weak wheats, which are generally
poor in gluten, contain less protein than flour from strong wheats,
which are rich in gluten. But by the use of " improvers " flour
from weak wheat is made to simulate flour from a stronger
wheat, although much inferior to it in protein.

The indiscriminate addition of such substances as strong hydro-
fluoric acid, phosphorus pentachloride, oxides and sulphides of
phosphorus, etc., to flour is most dangerous. It does not appear
desirable that such an indispensable foodstuff as flour, the purity
and wholesomeness of which are of first importance to the com-
munity, should be manipulated and treated with foreign sub-
stances whose utility from the point of view of the consumer is
more than questionable.*

The general conclusion to be drawn from the result of these
investigations is that millers, in the desire to produce fine flour
of dazzling whiteness at as great a profit to themselves as
possible, have considerably impoverished the flour in its protein
content, fat, and mineral constituents ; that, in order to be able
to make use of inferior wheats, or increase the commercial value
of the flour, they have introduced a method of bleaching with
nitrogen peroxide gas, and a system of improving the " strength "
of low-grade flours by the addition of foreign chemical substances.
Neither the effects of the bleaching processes nor the addition of
" improvers " in any way increases the dietetic value of the
* Lancet, Local Government Reports, vol. i., 1911.

TROPICAL FOOD MATERIALS 49

bread to the consumer, while evidence is not wanting that these
innovations are distinctly harmful, and may even be dangerous.

It may be concluded, therefore, that while a " standard " flour,
containing 80 per cent, of the whole grain, and including the germ
and semolina, permits of millers making use of inferior grades of
wheat for its production — a deception that is already practised,
and capable of considerable extension in the manufacture of
ordinary white flour — at least, it gives no incentive to the gross
adulteration of flour with harmful chemical substances, which,
from the Government report above referred to, would appear to
be only too common.

It is quite evident that in the evolution of the modern processes
of milling, so far as the nutritive value of flour is concerned, a
false standard has been set up — viz., one based on the colour,
lightness, and texture of the products. In order to approach as
nearly as possible to this standard, and at the same time produce
a flour that will give the largest yield of the most attractive bread
from a given quality of wheat, millers have not scrupled to reduce
materially the important nutritive constituents of the flour, and
to enhance its commercial value by methods that are distinctly
deceptive, and in their effects not without danger to the public.
If the only true criterion of a high-class flour — viz., the real
nutritive value of the bread obtained therefrom — were adjudged
the standard by which flours would be graded, there is very little
doubt that millers would soon find it was to their own interests
to place flour on the market that would meet all requirements,
and all danger from inferior wheats and from adulteration with
noxious compounds would be at an end.

From the results of feeding experiments carried out on a large
scale in India with wholemeal obtained by grinding a good-class
wheat, it has already been shown that 80 per cent, of the protein
will be absorbed. This wholemeal has not been deprived of any
of its nutritive material, and probably contains a slightly larger
amount of the bran and outer layers than would be the case in
" standard " bread. An equally high percentage of protein
absorption should be possible from " standard " flour milled
from a good class of wheat.

In another connection it will be necessary to consider the effects
on the system of the retention of as much of the wheat grain as
possible in flour ; at present the relative degrees of absorption
shown by different grades of flour require examination.

4

50

THE PKOTEIN ELEMENT IN NUTRITION

From an average of a considerable number of experiments by
Rubner, Atwater, Zuntz and Magnus-Levy, Goodfellow, and
others, Hutchison works out the loss of the nutritive constituents
of wholemeal and white bread, when it formed the main part of
the diet, as follows :

Constituents.

White Bread.

Wholemeal Bread.

Total solids
Protein
Ash
Carbohydrates

4'5 per cent.
20-0
25-0
3-0

14-0 per cent.
20 to 30 per cent.
51-0
6-0

There seems to be a considerable degree of confusion with
regard to the terms used in the description of breads. Thus
brown and wholemeal are used synonymously to apply to bread
prepared from flour containing part of the bran, but not the
germ ; whereas real wholemeal flour should contain the germ in
addition. There is a good deal of evidence that a large proportion
of the brown or wholemeal bread placed on the market is prepared
from low-grade flour, to which has been added a certain amount
of bran. As might be expected, the absorption of the nutritive
constituents of such bread must necessarily be poor.

The most recent work on the absorption of the constituents of
different flours is that carried out by Professor Snyder in
Minneapolis for the U.S. Department of Agriculture. Young
healthy men were fed on bread prepared from three flours :

1. Graham, made by grinding the whole wheat.

2. Entire wheat, corresponding approximately to " standard "
bread — includes the germ and semolina.

3. Patent, ordinary white flour of best quality.

The proportions assimilated were ascertained by analyses of
the food taken, and of the total excreta over a period of time in
the usual way. The results obtained were —

Different Flours.

Protein Absorbed.

Carbohydrate Absorbed.

Graham flour
Entire
Patent ,,

74-9 per cent.
82-0
88-6

89-2 per cent.
93-5
97-7

These figures may be accepted as being as accurate as it is
possible to obtain with a material that varies in its chemical

TROPICAL FOOD MATERIALS

51

composition so much as wheat. It will be evident that the old-
fashioned household bread, " standard " bread, and the. bread
prepared from ata in India — all of which contain the germ and
semolina — approximate closely to one another in their proximate
principles, and show practically identical percentages of absorp-
tion and assimilation. The following table gives the results
arrived at :

Different Flours.

Protein
Present.

Protein Carbohydrates
Absorbed. Present.

Carbohydrates
Absorbed.

Per Cent.

Per Cent. Per Cent.

Per Cent.

" Patent " flour . .

7-9

88-6 76-4

97-7

" Standard " flour

( 82-0 70-0

93-5

India ata . .

11-5 to

1 80-5 70-9

96-5

Old-fashioned house-

14-2

\

hold flour

( 80-0 70-0

95-0

It may therefore be concluded that while the protein element
of the fine white flours is slightly better absorbed than in the
case of real wholemeal or " standard " flour, the decided inferi-
ority it shows in the amount of protein presented lessens its
dietetic value very considerably, and, in the case of those with
whom bread constitutes the main source of nutriment, entails a
much lower level of nitrogenous interchange than would be
attained on a similar quantity of flour containing the highly
albuminous germ and semolina. Thus, for instance, a person
living on 1,000 grammes of " patent " flour, and another on
1,000 grammes of " standard " flbur, ata, or the old household
flour, the first, with " patent " flour, would attain a level of
nitrogenous metabolism equal to 79 multiplied by 0-88, or about
69-6 grammes of protein per day. The second, taking the
average protein content at 12-5 per cent., and the coefficient of
absorption at 81 per cent., would metabolize 101-25 grammes of
protein per day. So that, from the standpoint of protein inter-
change within the body, the modern impoverishing methods of
milling may affect very seriously the dietetic value of bread, and
thus lower the stamina of those largely dependent on it for their
nutrition. Leaving out of consideration the harmful effects of
bleaching and the addition of so-called " improvers," there can
be little doubt of the superiority of real wholemeal bread to
ordinary white bread in protein content, and in the level of protein
metabolism possible of attainment. But in addition to this there
is another factor to be taken into consideration — viz., the relative

52 THE PROTEIN ELEMENT IN NUTRITION

values of white and wheat-meal breads on the growth and develop-
ment of the body ; this is probably associated with other con-
stituents of the wheat grain besides protein. A large number of
experiments have now been carried out with the view of con-
trasting the values of white bread, " standard " bread, and whole-
meal bread in nutrition and growth. Flack and Hill have shown
that white bread is very inferior from this standpoint. It is not
necessary to enter into details ; all that need be said at present
is that the superiority of wheat as a foodstuff appears to be due
partly to gluten and partly to an organic base. A similar base
can be extracted from the pericarp of rice or outer layers of the
rice grain by acid alcohol. It is not a phosphorized compound.
The absence of this from white rice apparently is the cause of
beri-beri.* There is a considerable amount of evidence that
white flour is depleted to a very large extent of this important
organic base, whilst, on the other hand, it is present in sufficient
quantity in " standard " and real wholemeal flour to meet the
requirements of the body.

Another typical Indian food material is maize or Indian corn.
It is prepared for use in different ways. Usually the grain is ground
to meal in exactly the same way as wheat. Sometimes the indi-
vidual grains are separated from the cob and roasted, when they
swell up and burst ; in this form it is similar to the American pop-
corn. Often the cob, with adherent grains, is roasted ; the maize
is then eaten with butter and salt. Maize is extensively employed
as a food material by the people of Behar, United Provinces, and
other parts of India suitable for its cultivation ; strangely enough,
it is not used to any great extent in the feeding of prisoners.

In India the average protein content of maize was found to be
9-55 per cent., fully 2-5 per cent, less than wheat contains. Its
fat is higher than any of the other Indian cereals, being almost
twice as high as in wheat. As already pointed out, zein is the
typical protein of maize, and it differs in its properties from the
gluten of wheat or the proteins of other cereals. Owing to the
absence of gluten corn-meal, cannot be baked into porous leaves
like wheaten-meal. The bread is usually, therefore, of the un-
leavened type, and is of a granular appearance. The germ and
husk are removed in the modern methods of milling, and the

* Casimir Funk has recently isolated this body, which he terms " the beri-
beri vitamine," from the polishings of rice. He has determined its chemical
nature, and demonstrated its wonderful effects on the polyneuritis set up in
fowls by a diet of rice deprived of this substance (Journal of Physiology,
December, 1911).

TROPICAL FOOD MATERIALS

53

remaining endosperm is ground alone and purified by means of
air currents. About 30 to 35 per cent, of the entire weight of the
grain is rejected as offal, which consists of the hull, germ, floury
particles, and some of the flinty portions of the corn. The effect
of these losses is to lessen the protein, fat, and mineral con-
stituents, and raise the carbohydrates. Thus —

Different Forms of Maize.

Protein.

Pat.

Carbohydrates.

Mineral
Matters.

Per Cent.

Per Cent.

Per Cent.

Per Cent.

Indian-corn

9-7

5-4

68-9

1-5

Corn meal

8-5

4-6

72-8

1-3

(fine)

6-8

1-3

78-0

0-6

This method of milling has almost entirely replaced the old-
fashioned crushing of the corn between grooved mill-stones to
the desired fineness — the coarse particles of the skin and bran
only being rejected. In India the old method is the only one in
use, so that it is corn-meal or wholemeal that is employed as food
material.

Maize-meal, either baked or in the form of porridge, is very well
digested and absorbed by the intestinal tract. In a large number
of experiments* on prisoners in Bengal where maize was given
along with rice, it was found that the protein element was as
well absorbed as that of wheat, when the two foodstuffs were
given under the same conditions.

Rubnerf places the absorption of the protein of maize at
81-8 per cent., and its dry matter at 82 per cent. Later work
on the digestibility of foods prepared from corn-meal in America
would show that the protein constituent is slightly less thoroughly
digested than that of wheat ; but the difference is too slight to be
of much practical importance. Thus, Harcourt states that
74 per cent, of the protein and 99 per cent, of the carbohydrates
of corn-meal porridge are absorbed, and experiments at the
Marine Experiment Station gave similar figures. With the finer
cornmeals from which the germ, hull, and other coarser particles
have been removed, the absorption of protein ranges from 77 to
86 per cent. The carbohydrates are almost completely utilized
by the body. Of the different cereals experimented with in
India, maize is decidedly superior to all with the exception of
wheat ; it is, therefore, difficult to understand why greater

* Scientific Memoirs, Government of India, No. 37, p. 158.
t Rubner. Zeit. f. Bidog., 1879, xv.

54 THE PROTEIN ELEMENT IN NUTRITION

advantage of it is not taken in the feeding of prisoners. In
America and Italy it forms the principal food for the majority
of the rural population. In 1900 one-third of the land under
cultivation in the United States was devoted to the maize crop,
and it forms 5 per cent, of the cropped area of the United
Provinces of India.

Maize has been popularly regarded as indigestible ; as a good
winter food, but too " heating " for summer use. How these
ideas originated it is difficult to say ; they obtain no support
either from experimental work nor from the almost universal use
made of it in the Southern United States, Mexico, and Mediter-
ranean regions. Woods * sums up a discussion on its merits by
saying—

" That it is wholesome and well suited to its numerous uses as
a food material is abundantly proved by its long-continued use
under a great variety of circumstances and conditions, and the
high opinion in which it has always been held. Scientific investi-
gations have abundantly justified the popular conclusions on the
subject."

Another great advantage of maize is its cheapness. Of all the
cereals it provides a greater return in protein, fat, carbohydrates,
and energy for the same outlay.

It seems a pity that greater use is not made of such an excellent
and cheap food by the poorer classes in Europe and in the feeding
of prisoners in India . The Chinese employ maize very extensively,
and on it are able to endure great fatigue, whilst their general
physique and stamina reach a high level.

Of the other cereals utilized as foodstuffs in India that have
been investigated — barley, juar, bajra, and marna — little need
be said. They are all much inferior to wheat or maize in their
gross chemical constituents, and in the amount of assimilable
material they contain.

Barley (Hordeum vulgare) in India is usually grown mixed
with pulses, sometimes with wheat. Both alone and in admix-
tures it is generally considered difficult of digestion. It is chiefly
used in the form of powder or flour of the parched grain.

The analyses of Indian bar ley-meal f showed —

Protein 8-92 per cent.

Carbohydrates 76-10

Fat . . 1-90

* Woods, "Food Value of Corn Products," Bulletin No. 298. U.S. Depart-
ment of Agriculture.

f Scientific Memoirs, Government of India, No. 48.

TROPICAL FOOD MATERIALS 55

From an average of the results obtained in feeding experiments
on batches of Indian prisoners, the absorption of the nitrogenous
and carbohydrate constituents worked out to be — protein,
57-6 per cent. ; carbohydrates, 96-0 per cent.* In his digestion
experiments on the Japanese, Oshima*)" found practically identical
figures — viz., protein, 59-8 per cent. ; carbohydrates, 96-7 per
cent., absorbed.

In dietaries where barley is substituted for part of the wheat,
the average percentage of protein absorption falls, the extent of
the fall depending on the degree of substitution. This takes
place on an extensive scale all over India, as the wheat is grown
largely mixed with barley, so that on being ground to meal there is
obtained a mixture of wheat and barley. The protein absorption
from this mixture usually averages between 65 and 70 per cent.

Juar (Andropogon Sorghum or Sorghum vulgare) is one of the
high-growing millets. It is seldom grown alone, usually with
some of the creeping pulses. Juar is one of the most important
of the rainy-season crops of India, forming with rice and wheat
the chief staple foods of the country. It is ground to meal, and
from it are prepared unleavened bread, porridge, and other
preparations. Its chemical composition was found to be —

Protein 7-67 per cent.

Carbohydrates 67-26

Fat 2-77

Like barley, it shows very defective protein absorption, the
average over a large number of feeding experiments being —
protein, 53 per cent. ; carbohydrates, 97-8 per cent., absorbed.

Bajra (Pennisetum typhoideum) is another large millet. As an
article of food it is much esteemed in some parts of India. The
seeds are ground to meal and baked into cakes, or it is prepared
as porridge. Boiled with milk, it is said to form a light and
pleasant meal for invalids. The chemical composition of this
food was found to be —

Protein 8-72 per cent.

Carbohydrate? 7340

Fat 1-90

Over a large number of observations, the average protein
absorption worked out inferior to that of all other cereals, being
only 494 per cent.

* Scientific Memoirs, Government of India, No. 48.

t Oshima, U.S. Department of Agriculture, Bulletin No. 159.

56 THE PROTEIN ELEMENT IN NUTRITION

These three foodstuffs, barley, juar, and bajra, are very
inferior when used alone or as the main constituent of a diet, as
they exhibit so poor an absolute and relative absorption of the
protein element. Thus, to take as examples* three of the ordinary
diets arranged for prisoners in India, the following are the results :

Bajra 24 ozs. ]

Dais 6 „ [intake of nitrogen, 15-9798 grms.

Vegetables . . . . 6 ,, J

Of this 9-5291 grammes of nitrogen were absorbed, or 59-6 per
cent, of the total nitrogen offered in the diet.

Juar 22 ozs. ]

Dais 8 „ [intake of nitrogen, 16-2748 grms.

Vegetables .. .. 6 „ J

Of this 8-9992 grammes of nitrogen were absorbed, or 55-3 per
cent, of the total nitrogen offered in the diet.

Barley 22 ozs.]

Dalg81 2 " /-Intake of nitrogen, 14-3793 grms.

Vegetables '.'. '.'. 6 ',', 1

Of this 9-2264 grammes of nitrogen were absorbed, or 64-1 per
cent, of the total nitrogen offered in the diet.

These results should be contrasted with the level of nitrogenous
metabolism attained on a diet where a good class of wheat forms
the principal cerealf :

Wheat 23 ozs.]

Dais .. .. .. 4 ,, [intake of nitrogen, 16-714 grms.

Vegetables .. .. 6 ,, J

Of this 13-651 grammes of nitrogen were absorbed, or 81-6 per
cent, of the nitrogen offered in the diet.

It will be evident from these results that there is a very large
nitrogenous residue left over in the intestinal canal when food
materials with a low coefficient of protein absorption, such as
barley, juar, or bajra, form the main part of the diet. This
residue provides a splendid culture medium for the growth of
putrefactive micro-organisms, and is therefore likely to predispose
to diarrhoea, dysentery, and other intestinal disorders.

Another disability attached to such foods is that, in order to
maintain the physiological needs of the body, they require to be
taken in such large quantities that the carbohydrates and caloric
value of the dietaries become very excessive. Thus, in the three

* Scientific Memoirs, Government of India, No. 48, p. 131.
f Ibid., No. 48, p. 54.

TEOPICAL FOOD MATERIALS

57

examples given above, the carbohydrates averaged 628 -7 grammes,
and the heat value 3,312 calories, which, for the average weight
of the prisoners, works out at over 60 calories per kilo of body
weight.

It is probable the explanation of the low percentages of
nitrogen absorption shown by barley, bajra, and juar is that the
proteins of these cereals do not exist in forms capable of absorp-
tion. If this explanation should turn out to be the true one, it
would account for the great loss of protein in the faeces with
dietaries into whose composition any of these cereals enters at
all largely. Whatever the true explanation may be, these food-
stuffs, so far as their protein content is concerned, exhibit a very
poor degree of absorption ; so much, indeed, is this the case that
they are quite unsuitable to act as principals in the formation of
dietaries.

The last class of food materials that it will be necessary to
discuss is that derived from the Leguminosse. The different
legumens used as food include the following dais :

Arhar dal (Cajanus indicus).
Massur dal (Erbum lens).
Gram dal (Cicer arietinum).
Mung dal (Phaseolus mungo).
Mattar dal (Pisum sativum).
Kalai dal (Phaseolus radiatus).
Urid dal (Phaseolus radiatus).

These dais all resemble the European pea in appearance, but
vary considerably in size. They are chiefly characterized by
their richness in protein, being termed for this reason " the poor
man's beef." The chemical composition of the different dais
shows the protein content to be uniformly high, the carbohydrates
well represented, and fats as a rule low in amount, although gram
dal has a very high percentage of fat :

Foodstuffs.

Protein.

Carbohydrates.

Fat.

Per Cent.

Per Cent.

Per Cent.

Mung dal

23-62

53-45

2-69

Massur dal

25-47

55-03

3-00

Gram dal

19-91

54-22

4-34

Kalai dal ...

22-58

58-02

1-10

Mattar dal ...

22-01

53-97

1-96

Arhar dal

21-70

54-06

2-50

Urid dal

22-33

55-22

1-95

58 THE PROTEIN ELEMENT IN NUTRITION

As a source of nitrogen these legumens in the dietaries of the
people of the East play a very important part, and take the place
of animal food to a considerable extent. They are extensively
used all over India and the tropics, and one member, the soy bean,
has been employed for centuries by the Chinese and Japanese in
the manufacture of food preparations. Taking the different
countries together, they rank next to wheat and maize in impor-
tance among vegetable foods, and as a source of protein are
superior to most of the cereals.

The chief protein of the pulses is legumin, which possesses the
property of uniting with salts of lime, and the compound so
formed is insoluble in water. Pulses should, therefore, never be
cooked in hard water, unless the lime in the water has been
precipitated by the addition of bicarbonate of soda. " Some of
the protein of pulses exists in the form of nitrogen compounds
which are not albuminoid — which are not flesh-formers, in fact—
and which, for all we know, may be entirely without nutritive
value. These bodies are simpler in constitution than the albumin-
oids, and are often of the nature of alkaloids — lupinine, a bitter
basic substance from lupines is one of these ; asparagine is another.
But the quantity of nitrogen existing in the pulse in the form of
non-albuminoid compounds of all kinds is small, not exceeding
3 to 5 per cent, of the total albuminoids in the common kinds of
ripe pulse ; in the seeds, stems, and pods of the unripe plants it is
very much larger."*

Pulses are prepared in India for food in different ways ; occa-
sionally they are ground to meal, and the meal baked with the
cereal into bread of the unleavened type ; more often they are
boiled in water into a form of porridge or thin gruel, and used as
a sauce with the bread and vegetables. Some forms, as gram
dal, are parched and eaten dry. As will be shown later, the
method of cooking pulses makes a considerable difference in the
absorbability of the protein element, and probably also on the
carbohydrate and fat absorption. When cooked, dal, in what-
ever form, takes up a large quantity of water, usually about three
and a half times its own weight. This increase in water means a
corresponding increase in bulk, which may affect seriously the
absorption of protein when the dal is given in large quantities, or
when it is combined with a cereal, such as rice, that is of a bulky
nature.

* Church, " Food Grains of India."

TKOPICAL FOOD MATERIALS 59

Considering the importance of the pulses as food materials, up
to within recent years comparatively few investigations had been
made into the absorption of their several constituents. Hof-
man,* in 1869, reported, as the result of some experiments, that
47 per cent, of the protein of a diet of bread, lentils, and potatoes
was excreted, as compared with a loss of 18 per cent, of meat
protein eaten by the same person. Strumpell,* experimenting
with lentils soaked in water and cooked in the usual manner,
found about 40 per cent, of the protein excreted, whilst investiga-
tions into the absorption of pea and lentil flour, properly cooked,
showed that under 10 per cent, of the protein is lost in the
faeces. Rubner* made experiments with dried hulled peas,
cooked for two or three hours, until soft, and then passed
through a sieve. When large quantities were eaten he found an
absorption of—

Protein 72 per cent.

Carbohydrates 93

Fat 25

Ash 64

with smaller quantities about 83 per cent, of the protein was
absorbed. Malfatti,* Richter,* and Prausnitz* obtained some-
what similar results, and the important point was demon-
strated that lentils are more thoroughly digested and ab-
sorbed when cooked in distilled water than when hard water
is used.

Oshima,* in Japanese investigations, found the coefficient of
digestibility for protein was 65 per cent., and that for carbo-
hydrates 86 per cent. Snyder,| experimenting with legumes
when eaten in combination with other foods in an ordinary mixed
diet, obtained very uniform results for the different subjects
under observation ; the absorption of protein was found to be
80 per cent., and carbohydrates 96 per cent.

Later investigations by Wait J carried out on a large scale under
more normal conditions — i.e., the quantity of pulses not excessive,
and given in an ordinary mixed diet, have extended our know-
ledge of the nutritive value of the pulses very considerably.
The averages of the results obtained are given in the table
on p. 60.

* Quoted by Wait, U.S. Department of Agriculture, Bulletin No. 187.
t Minnesota Station, Bulletin No. 92.
J Wait, loc. cit.

60

THE PROTEIN ELEMENT IN NUTRITION

Digestibility of Total Diet.

Digestibility of
Legumes.

Character of Diet.

Protein
p^r Cent.

Fat
per Cent.

Carbohy-
drates
per Cent.

Protein
per Cent.

Carbohy-
drates
per Cent.

Basal ration

91

95

98

_

Basal ration and kidney

beans

78

89

95

77

94

Basal ration and white beans

81 88

95

78

96

Basal ration and cow peas,

whippoorwill

77 91

92

70

87

Basal ration and cow peas,

clag . .

81 93

94

74

88

Basal ration and cow peas,

lady

87 91

97

83

95

It is evident from these results that the legumes experimented
with are somewhat less thoroughly digested than other common
food materials, and that the addition of the legumes to the basal
diet caused a lowering of the percentages of absorption.

In investigating the nutritive value of the Indian dais two
factors were found to affect seriously the absorption of protein.
One of these was the bulk of the basal diets, and another was the
large quantities of the dais given in some of the gaol dietaries.
With regard to the latter point, it has been the favourite method
of raising the nitrogenous element, without increasing the carbon-
aceous, to give large quantities of the pulses in these vegetable
dietaries which would be otherwise deficient in protein. Thus, in
the gaols of the United Provinces, dal in quantities of over
8 ounces enters into the composition of some of the dietetic
combinations sanctioned for prisoners. In such cases the protein
absorption from the diets was found to be very poor, and the
amount of nitrogen in the faeces exceedingly high.

An example* will make this clear.

Five prisoners were kept on the following diet for five days,
the faeces for the period separated in the usual manner, and the
nitrogen content determined :

Juar

Urid dal . .
Arhar dal . .
Vegetables . .

22 ozs. presenting 7-4844 grms. of nitrogen.
6 ,, ,, 6-2940

2 ,, ,, 1-9964

6 , 0-5000

Of a total intake of 16-2748 grammes of nitrogen, only
8-9992 grammes were absorbed, or 55-3 per cent, of the nitrogen
offered in the diet. The faeces gave 7-2756 grammes of nitrogen
per man daily.

* Scientific Memoirs, Government of India, No. 48, p. 43.

TKOPICAL FOOD MATERIALS 61

It will be noticed that over half of the nitrogen of this diet is
derived from the pulses, which is beyond the percentage from
which the maximum protein absorption will be obtained. From
the coefficients of digestibility worked out for the different food-
stuffs present in this diet, over 60 per cent, of its nitrogen should
have been absorbed, so that the excessive quantities of pulse
cause decrease in the actual and relative absorption of its protein
element.

In connection with this point Church states : " The digesti-
bility of the albuminoids in pulse as compared with that of the
corresponding compounds in the cereals has usually been regarded
as low. In general, they are not only digested and absorbed at
a slower rate, but a larger proportion of the total amount present
remains unattacked and unused in its passage through the
alimentary canal. The proportion of unused to used albuminoids
is proportionately highest when the pulse forms the largest part
of the ration ; it is much reduced when the pulse constitutes not
more than one-fourth of the daily food."* It was found in
dealing with the gaol dietaries of Bengal and the United Provinces
that it was useless to increase the quantity of pulse beyond an
average of 5 ounces per man daily. Larger quantities than this
seem to act more as an irritant than as a food, and have a decided
tendency to set up diarrhoea, thus seriously deteriorating the
value of the diet.

In dietaries where the pulse is improperly cooked — as, for
instance, is the case in the method of parching gram dal — it is
probable that a large proportion of the contained nutriment never
comes into thorough contact with the digestive juices, and passes
out in the faeces practically unchanged. Gram dal, on this
account partly at least, showed the poorest percentage of protein
absorption of all the pulses investigated. With regard to the
other factor that was found to affect the protein absorption from
the pulses — viz., the total bulk of the diet — experiments carried
out with the voluminous rice dietaries of Bengal prisoners showed
that it was futile to increase the nitrogen intake by the addition
of pulse beyond a certain optimum quantity, in the hope of
obtaining an augmented protein absorption.

From actual observationsf it was demonstrated that, with a
constant intake of nitrogen derived from rice, but with a varying

* Church, " Food Grains of India."

f Scientific Memoirs, Government of India, No. 37, pp. 66-71.

62 THE PROTEIN ELEMENT IN NUTRITION

intake of nitrogen derived from dal, no increase in nitrogenous
metabolism accompanied an augmentation of the nitrogen
presented in the form of pulse. Thus —

Batches of five men under observation for five days on each
separate diet :

Nitrogen of f N. of arhar dal . . 150-10 grms. showed 196-25 grms. absorbed,

rice and | N. of massur dal 188-40 ,, ,, 198-60 ,,

vegetables + 1 N. of massur dal 171-30 „ ,, 198-13 „

constant. IN. of mung dal .. 160-81 ,, ,, 193-54 ,,

Other results were found to corroborate the above finding.
Thus—

Diets Investigated.

Grammes of

Per Cent, of

Nitrogen

Nitrogen of Diet

Absorbed.

Absorbed.

Burma rice . .

20 ozs.\ , /Massur dal. .

6 ozs.

8-12

56-87

Vegetables . .

6 „ )+{ „ „ ..

5 ,,

8-06

61-97

Country rice . .
Vegetables . .

26 ozs. \ /Mung dal ..

6 „ j+\ „ „ ..

6 ozs.

7 „

7-49

7-42

51-34
47-61

A large number of feeding experiments have been made on
Indian prisoners to determine the protein absorption from some
of the more common pulses in use. So long as the same sample
of dal was adhered to, very uniform results were obtained ; but
samples of the same pulses sometimes showed considerable
variations in protein content in the several gaols where investiga-
tions were carried out, so that an accompanying variation in the
coefficient of protein absorption was only to be expected. As
in the case of wheat, it was only with difficulty that good clean
samples of the several dais could be obtained, the usual condition
met with being a mixture of several varieties, and in the ordinary
gaol stock other types of seeds occurred that did not belong to the
lentils at all. Thus, the results* obtained for the absorption of
protein in the different gaols were —

BENARES GAOL.

Protein absorption from gram dal . . No. 27 shows 61-8 per cent.

,, 28 ,, 60-9
,, arhar dal and! 9ft R. ,

vegetables f " 28 "
,, arhar dal and\ on M.r\

vegetables / " '

* Scientific Memoirs, Indian Government, No. 48. Numbers refer to the
experiment^.

TROPICAL FOOD MATERIALS 63

NAINI GAOL.

Protein absorption from gram dal . . No. 62a shows 65-9 per cent.

„ » „ 62& „ 65-5
arhardal a,nd\

vegetables / " 55a " 83 8

arhardal and ""\ _,

vegetables / " 556 " 83 8

urid dal „ 56 „ 69-2

LUCKNOW GAOL.

Protein absorption from gram dal . . No. 69 shows 66-8 per cent.

„ 70 „ 65-7

„ 71 „ 68-2

C

arhardal and I " 80<fi

vegetables » "

arhar dal " „ 81'2

AGRA GAOL.

( No. 77^1

78 I
Protein absorption from gram dal . ,-c ' Lr. j-shows 62*9 per cent.

I " 83J

arhar dal ,, 91 ,, 73-6

arhar dal and ^ Q0

vegetables " 82

arhar dal and Qr- 70.0

io'o

, i 1

vegetables

„ urid dal and

vegetables | •• 8g J

The lowest figures were obtained in experiments on prisoners
in Agra Gaol, not only for the protein absorption from the pulses,
but also for that of the cereals. The explanation of this was the
more than ordinary contamination of the foodstuffs, and also,
in the case of the pulses, the very large quantities of these
materials that were given in the dietaries. An examination of
the experiments, Nos. 85, 86, 88, and 91, from which the absorp-
tion is very poor, shows that about 50 per cent, of the total
nitrogen of the diets is derived from pulses, and there can be
little doubt but that the quantity of these foodstuffs from which
the best absorption is obtained has been passed. Thus —

No. 85.
Wheat .. 14 ozs. presents 6-3504 grms. N. U total intake of

fTua,r , . • • 10. " •• nitrogen per man

Urid dal .. 4 ,, ,, 4-1960 „ lailv of 17-^24

Gram dal.. 4 „ „ 3-0840

Vegetables 6 ,, „ 0-5000 „ J g

Of this only 10-2509 grammes nitrogen were absorbed, or
584 per cent, of the total nitrogen offered in the diet ; 7-2815
grammes nitrogen were recovered from the faeces.

64 THE PROTEIN ELEMENT IN NUTRITION

No. 86.

Wheat . . 10 ozs. presents 4-5360 grms. N. ^ A . . } ;nfifli™ nf

Juar .. 10 „ 3-4020 „ A *?tal J^fLJ
TT • j j i nitrogen per man

Und dal .. 4 ,, ,, 4-1960 ,, lailv nf TV718

Gramdal.. 4 3-0840

Vegetables 6 „ „ 0-5000 „ j grms'

Of this only 9-106 grammes nitrogen were absorbed, or 57-9 per
cent, of the total nitrogen offered in the diet ; 6-612 grammes
nitrogen were recovered from the faeces.

No. 88.
Wheat . . 10 ozs. presents 4-5360 grms. N. ^ A ^tak*

ai 4 4-i96o

Gramdal.. 4,, „ 3-0840

Vegetables 6 „ „ 0-5000 „ j 17'0788 grms

Of this only 9-8038 grammes nitrogen were absorbed, or 55-9 per
cent, of the total nitrogen offered in the diet ; 7-275 grammes
nitrogen were recovered from the faeces.

No. 91.

Juar . . 22 ozs. presents 7-4844 grms. N. "| A total intake of

Uriddai .. 6 ,, ' ,, 6-2940 „ I nitrogen per man

Arhardal.. 2 „ „ 1-9964 „ j daily of 16-2748

Vegetables 6 „ „ 0-5000 „ J grms.

Of this only 8-9992 grammes nitrogen were absorbed, or 55-3 per
cent, of the total nitrogen offered in the diet ; 7-2756 grammes
nitrogen were recovered from the faeces.

These results are sufficient to show how very inferior the absorp-
tion of nitrogen is from diets of a type in which the main source
of protein is the pulses — i.e., diets in which the other constituents
being poor in protein, an effort is made to bring the diet up to
the normal protein standard by increasing the quantity of pulses
to an excessive degree. The effect of large quantities of pulse is
not only to cause a decrease in the percentage of protein absorp-
tion from the pulses themselves, but also to lessen the degree of
protein absorption from the other constituents of the diet. In
Agra Gaol the amount of pulses entering into the composition
of the diets experimented with was too high, practically never
less than 7 ounces, and often over 8 ounces ; this would account
for — partially at least — the lower coefficients of absorbability
obtained for the foodstuffs investigated in that gaol. On the
other hand, the wheat was of poor quality, containing a large
percentage of barley and other contaminating factors, so that a

TROPICAL FOOD MATERIALS

65

high level of nitrogenous metabolism could not be expected from
diets made up of poor wheat and excessive quantities of pulses.
Selecting the results obtained for the coefficients of digesti-
bility where the foodstuffs were of fair quality and where the
amount of any individual food material, such as the pulses, was
not excessive, the following may be accepted as representing the
average coefficients of digestibility for the Indian cereals and
pulses investigated :

Food Materials.

Coefficient of
Protein
Absorbability.

Coefficient of
Carbohydrate
Absorbability.

First quality of wheat
Ordinary wheat
Arhar dal with vegetables
Arhar dal

Per Cent.
80-6
70-3
82-8
86-5

Per Cent.

96-5
92-3
96-8

Munff dal

85*6

Gram dal

64*9

97'7

Urid dal

69-2

Barley

57'6

96-0

Juar . . . . . . . . .

53-6

97-8

Bajra

49-4

Vegetables

76-3

In the experimental work necessary for the determination of
these coefficients, the aim ever kept in view was to maintain the
characteristics of a normal well-balanced diet. In no instances
were large quantities of any one food material added, as seems to
be the usual custom in investigations of this nature, so that the
coefficient of absorbability presented above are such as would be
likely to hold good for the protein and carbohydrate con-
stituents of the foodstuffs when consumed in ordinary quantities,
and not those obtained when some one food material is given out
of all proportion to what would ever be the case except under
artificial or experimental conditions.

It has already been pointed out that the ordinary wheat sup-
plied to the gaols is mixed to a considerable extent with barley
and other grains. This accounts for the much lower coefficient
of protein absorption obtained for ordinary wheat than that
shown by wheat of good quality — a difference of just over 10 per
cent. The gram dal was investigated under conditions that were
not conducive to a high degree of protein absorption ; it was
eaten in the form of parched gram, practically not cooked at all,
and retaining all its cellulose and other elements, a certain

5

66 THE PROTEIN ELEMENT IN NUTRITION

amount of moisture alone having been got rid of. Strumpell
showed long since under such conditions, when pulses are not
given in a state of fine division and when badly cooked, that the
loss of protein may rise to 40 per cent. However, parching was
the customary method of preparing gram dal for consumption,
and it was therefore desirable to determine the protein and
carbohydrate absorption under local conditions. Over a large
number of observations the protein absorption was never found
to fall below 61 per cent., the average working out at 65 per cent.
Of all the varieties of dal experimented with, arhar dal was
found to give the highest coefficient of protein absorption.
Under favourable conditions, when combined with first quality
of wheat, over 86 per cent, of its protein is taken up by the
intestinal tract. This variety is the favourite form of dal with
the wheat-eating population of India, and it is quite probable,
in the light of Pawlow's investigations, that the desire for this
food material is a factor that must be taken into consideration
in any explanation of the high degree of protein absorption
shown by arhar dal. Although it was impossible to obtain
uniform results for the absorption of the protein of the foodstuffs
in the bulky dietaries of Bengal gaols, when the volume of these
diets was decreased to rational proportions, the coefficient of
protein digestibility of arhar dal worked out to be practically
identical with that given in the above table.* Under similar
conditions of decreased bulk the absorption of the protein of
mung dal — the favourite form with the rice-eating Bengali —
was found to be on the average about 85 per cent.f

With regard to the other varieties of the pulses, massur, kalai,
and mattar dais, no exact figures representing the percentages of
protein absorption could be determined, as these varieties were
only used in the bulky rice dietaries of the Bengal gaols. None
of them appeared to give as good results as arhar and mung dais,
but without experiments under conditions where the volume of
the dietaries is such as the stomach can successfully cope with,
it is not possible to determine accurately the degree of protein
absorption. These dais are not made use of in the less bulky
wheat diets of the United Provinces^

* Scientific Memoirs, Government of India, No. 37, p. 147. f IbM», P- 149-

CHAPTER IV
THE PROTEIN METABOLISM OF MANKIND

HAVING surveyed in general terms some of the food materials
extensively used in different countries, and having examined
their gross chemical composition and the averages of the per-
centage absorption of their proximate principles, we shall now
take into consideration the dietaries of mankind in general, and
discuss the nutritive requirements and the extent of nitrogenous
interchange attained by the various peoples concerning whom
information is available.

In his introductory remarks on the general principles of
dietetics Sir Lauder Brunton states : " The subject of food is
one upon which countless experiments have been made by
myriads of men during thousands and perhaps millions of years.
In all parts of the world, from prehistoric times until now, men
have been constantly engaged in finding out what things were good
to eat and what things they had better avoid." It is only, how-
ever, within comparatively recent times that the study of dietetics
has been accurately pursued and placed on a scientific footing.
Students of nutrition from different parts of the world have laid
their contributions at the feet of Knowledge, and Wisdom and
Understanding are gradually emerging from darkness into light.

Japan, Russia, and the different European countries, have all
made valuable additions in the advances recorded, but, at the
present time, to none do we owe the same debt as to America
for the stimulating influence of her many workers in this field,
and for the exceedingly valuable contributions they have made
to the scientific pursuit of the principles of proper feeding.

In the following pages it will be found necessary to make
reference to many of those engaged in this line of research, as,
for instance, Atwater, Langworthy, Benedict, Folin, etc., in
America ; Zuntz, Ranke, Pfliiger, v. Noorden, and others, in
Germany ; but it is only meet that special mention should be

67

68 THE PROTEIN ELEMENT IN NUTRITION

made of Chittenden, who, in first stirring the nutritional pool
by the publication of his two well-known volumes, has done
more to awaken interest, stimulate research, and lift the
subject of dietetics from the playground of quacks and charla-
tans, than perhaps any of his predecessors. That good will
eventually accrue from the extensive investigations that have
followed on the publication of Chittenden's studies cannot be
doubted, and it may be hoped that before long the whole subject
of dietetics and food requirements may be lifted out of the vale
of empiricism, in which it has hitherto lain, and raised to one of
those pinnacles of fame reserved for the exact sciences.

DIETARY STANDARDS.

Many different methods have been employed in the determina-
tion of the gross amount of food consumed per capita of the people
of different countries. A rough average may be obtained from
a statistical survey of the amount of food materials available —
certain factors for waste being taken into consideration — this
amount divided by the total population will give a figure which
represents a general average, but which is of little use where
anything approaching accuracy is demanded. Russell* has
collected a great mass of information on the foodstuffs, diets,
and physical characteristics of different races and nations which,
although of great interest from many standpoints, is not sufficiently
detailed to be of any great service in arriving at the quantities
of the proximate principles present in the different dietaries.

A more accurate method of obtaining the desired information
is by means of what has been termed dietary studies ; in these
individuals, or groups of individuals, are kept under observation,
the total food consumed is carefully recorded, samples analyzed,
and the value of the dietaries in protein, carbohydrates, and fat
computed. This method may be undertaken when there is free
selection of food, or, as in public institutions, where the choice
of food is limited.

More accurate methods are those where the subjects under
observation are placed under suitable conditions for the analyses
of the food and excreta over a stated period ; again, there may
be free choice of food, or, if the intention is to study the effects
of different food materials, the choice may be limited. The
most laborious, but at the same time the most accurate, method
* Russell, " Strength and Diet," London, 1905.

THE PROTEIN METABOLISM OF MANKIND

69

is that of the respiration calorimeter, in which the total heat
generated in the body under different conditions, the waste
products, work done, etc., are measured and expressed in terms
of heat. The amount of potential energy to be supplied in the
form of food in order to maintain body equilibrium can be
computed from the heat given off from the body under the
different experimental conditions. By means of certain known
factors this required energy can be expressed as so much protein,
carbohydrates, and fat.

By means of these and other methods of statistical and ex-
perimental study a fairly accurate knowledge has been obtained
of the amounts of protein, carbohydrates, fat, and energy
ordinarily consumed by people of different classes and in different
countries. The knowledge thus derived has led to the general
acceptance of certain standards for the average food consumption
of different classes, and has brought out this fact : " That all
over the world people who can obtain such food as they desire
use liberal rather than small quantities ; and that the more active
or severe the work done, the larger the quantity of food eaten."*

The standards that have been most widely accepted, such as
those of Voit, Atwater, Rubner, and others, all agree pretty
closely in the quantities of their constituents with the average
dietaries to which custom and instinct have guided mankind in
the formation of his dietetic habits. These standards have been
generally regarded as representing the minimum amount neces-
sary for the maintenance of the average man, under average
conditions, doing a moderate amount of work, in health and
strength. Some of these standards are —

Protein.

Carbohydrate.

Fat.

Heat Value.

Grammes.

Grammes.

Grammes.

Calories.

Ranke

100

240

100

2,324

Munk

105

500

56

3,022

Voit

118

500

56

3,055

Rubner

127

509

52

3,092

Moleschott

130

550

40

3,160

Atwater

125

400

125

3,315

It will be observed that there is a general consensus of opinion
that the protein element should amount to over 100 grammes a
day, and that the energy value should be over 3,000 calories.

* Benedict, " The Nutritive Requirements of the Body," American Journal
of Physiology, 1906, xvi.

70

THE PROTEIN ELEMENT IN NUTRITION

Benedict,* by taking into account the large amount of data
available as a result of dietary studies in different countries,
gives the following estimates of the average food consumption
of people under certain circumstances :

Protein.

Subjects.

Fuel Value.

Total.

Digestible.

Grammes.

Grammes.

Calories.

People with active muscular

work, such as lumbermen,

athletes, etc.

175

160

5,500

People with ordinary muscular

work, such as carpenters,

farmers, labourers, etc.

115

105

3,300

People with light muscular work,
such as professional and busi-

ness men, clerks, etc

100

92

2,700

A selection of some of the available data is here presented.
A large number of results obtained from dietary studies have
been collected, but it would not serve any useful purpose to
go into a mass of details. Taking the results as a whole,
they conform very closely to the standard dietaries already
shown :

Subjects.

Protein.

Heat Value.

Grammes.

Calories.

Teamsters, marble-workers, etc., with hard

labour, Boston, U.S

254

7,804

Brewery labourers, Munich, very severe work . .
Brickmakers U S

223

222

5,692
6,464

Swedish workmen

189

4,726

Lumbermen, U.S.

185

6,400

Weavers, England

151

3,475

Average dietary of five halls of residence for

students in Edinburgh

143

3,979

Dietary of a students' club in Finland

157

3,984

Medical students, Sweden

127

2,723

Chinese laundrymen, U.S.

135

3,480

Professor, Japan

123

2,343

Average of twenty-one dietary studies amongst
the labouring classes in Dublin

98-5

3,117

Chinese dentist's family

115

2,705

Russian workmen

132

3,675

Average diet of a labourer's family in Edinburgh
Poor families in New York

107-7
75

3,228
2,087

Students, Japan

97

2,343

* Benedict, loc. cit.

THE PROTEIN METABOLISM OF MANKIND

71

It would therefore appear that in the different countries
where dietary studies have been carried out, those who have a
free choice of food arrange to eat such quantities as shall permit
of at least 100 grammes of protein intake daily. It is uncommon
to find much below this figure except in conditions of poverty ;
thus factory girls in Leipsic and sewing girls in London earning
poor wages have been shown to live on diets yielding little over
50 grammes of protein and less than 2,000 calories of total energy.
When muscular work is excessive or fatiguing, there is a great
demand for a high caloric and protein value of the diet. This
is recognized in the framing of the army rations of the different
nations in peace and war :

CALORIC VALUE OF RATIONS.*

Army Rations.

Peace.

War.

Great Britain : Regulation diet

2,946

3,987

Actual diet obtained

3,319

Germany

2,592

/small, 3,613
\>rge, 4,213

France

2,310

/small, 3,079
\large, 3,413

The requirements of the body for increased protein and energy
during severe muscular exertion is well exemplified in Atwater's
standards, which embody the results of modern investigations
into the diet of adults under different conditions :

Subjects.

Protein.

Calories.

Women with light muscular exercise

90

2,400

Women with moderate muscular work .

100

2,700

Man without muscular work

100

2,700

Man with light muscular work . .

112

3,000

Man with moderate muscular work

125

3,500

Man with hard muscular work . .

150

4,500

Taking the average weight of Europeans and Americans at
68 to 70 kilos, or about 11 stone, the standard dietary for a
man doing a moderate amount of work should offer 1-4 to 1-7
grammes of protein and 40 calories per kilo of body weight.

Turning now from dietaries of the European and American
type, on which an immense amount of work has been done, let

* Spriggs, " Sutherland's System of Diet and Dietetics." London, 1908.

72

THE PROTEIN ELEMENT IN NUTRITION

us examine the results that have been obtained with dietaries
peculiar to Japan, India, and the tropics.

Oshima,* in his digest of Japanese investigation on the nutri-
tion of man, gives the results of a large number of dietary studies.
Although these do not deal with the poorer classes or rural
population to any great extent, he has succeeded in collecting
a valuable amount of information on the foodstuffs and dietaries
of the Japanese. He shows that soldiers and sailors, and those
in comfortable circumstances in other classes, including pro-
fessional and business men and students, are in general well
nourished. The amounts of protein and energy in the diet of
these classes compare well with those in the diet of people under
similar circumstances in Europe and America, especially when
allowance is made for the smaller average weight of the Japanese.

The dietary studies with the poorer classes, including em-
ployees, prisoners, military colonists, and investigations on purely
vegetarian diets, show that the amount of protein is about
60 grammes per man daily and the energy about 2,500 calories.
The average body weight of the Japanese is computed to be
about 54 kilos ; this would mean a metabolism of 1-111 grammes
protein or 0-177 grammes of nitrogen per kilo of body weight,
as contrasted with 0-224 to 0-27 grammes nitrogen per kilo of
body weight in Europeans and Americans.

The amount of animal food in the Japanese dietaries is much
less than in the average American dietary. A comparison is
given of the total protein derived from an animal and other
sources in 25 Japanese and 185 American studies :

Dietary Studies.

Total Animal
Protein per

Cent.

Cereals per
Cent.

Legumes
per Cent.

Vegetables
per Cent.

25 Japanese studies . .
185 American ,,

38-0
61-2

47-5
30-5

8-2
2-0

6-3
6-3

A special characteristic of the Japanese diet, and also, to
some extent, of Indian dietaries, is that the amount of fat is very
low ; in Japan, also, dairy products are practically unknown.
In connection with the commonly accepted idea that the Japanese
are vegetarians, it is interesting to note that Oshima comes to
much the same conclusion as that arrived at in discussing the

* Oshima, U.S. Department of Agriculture, Bulletin No. 159.

THE PROTEIN METABOLISM OF MANKIND

73

food habits of the people of India — viz., that they are vegetarians
from force of adverse financial circumstances rather than from
principle, and, except in the case of a relatively small number of
strict adherents to Buddhism, they eat animal food whenever it
can be afforded.

Another misconception that Oshima refers to is the popular
belief that rice is the principal, if not practically the only, food
of the large majority of the Japanese and other Oriental people.
As has already been pointed out in connection with Indian
foodstuffs, rice is only cheap in those parts of the East where
the conditions necessary for its cultivation are favourable,
particularly where the rainfall is abundant. In Japan, as in
India, though rice is a very important article of diet, and is eaten
in relatively large quantities where it can be afforded, it is by no
means the only food material, nor is it in all cases the principal
cereal. In large tracts of India, away from the coast-line, rice
hardly enters into the dietaries of the people, being too expensive
for regular consumption, and is only used on special occasions
as a luxury. The proportion of total nutrients of the Japanese
diets supplied by rice Oshima gives as follows :

Dietary Studies.

Proportion of Total Nutrients supplied by Rice.

Protein.

Fat.

Carbohydrates.

Average 24 studies
9 „ (Navy)

Per Cent.
53-2
21-5

Per Cent.

23-0
10-4

Per Cent.
89-5
52-1

From statistics collated by the Department of Agriculture and
Commerce, Tokyo, showing the proportions of the different
vegetable foods consumed by the Japanese in 1880, the following
averages were derived as applicable to the country as a whole :

Rice

Barley and wheat

Millets, buckwheat, legumes, etc.

Tubers and other vegetables

Fruits

Sea algae

53-00 per cent.

27-00

13-90

6-00

0-05

0-05

So that cereals other than rice form by no means an unimportant
part of the whole dietary.

It will now be of interest to give summaries of the dietaries
investigated in Japan, and contrast them with results of dietary

74

THE PROTEIN ELEMENT IN NUTRITION

studies under the same conditions as nearly as possible in
America :

Dietary Studies.

Protein.

Fuel Value.

Grammes.

Calories.

Professional and business men :

Average of 13 studies

87

2,190

Professional men in United States :

Average of 14 studies

104

3,220

Medical students (Japanese) :

Average of 8 studies

98

2,800

Military cadets (Japanese) :

Average of 11 studies .. ....

113

3,185

College clubs in United States :

Average of 15 studies

107

3,580

Hard labour :

Rice-cleaner (Japan)

110-5

4,107

Jinricksha man (Japan)

158

5,050

Coal-miner (Japan)

145

2,660

Football team (United States)

226

6,590

Japanese Army :

Average of 261 studies

124

3,360

Japanese Navy :
Revised (1900) allowance, peace

151

3,250

American Navy

145

4,280

With regard to the army ration, when the weight of the soldiers,
which is undoubtedly less than that of European troops, is taken
into account, it will be seen to compare very favourably with the
protein content and energy value of the dietaries of the British
Army. Thus —

Army Rations.

Protein.

Fuel Value.

Average food supplied gratis to four
regiments
British soldiers in detention, withou
labour

British
b hard

Grammes.
133
127

Calories.
3,369
3272

British Army minimum war ration
Africa)

(South

138

3 903

Russian Army war ration (Manchuria) . .
Japanese Army war ration (Manchuria)

187
158

4,891
4,343

It is evident from these figures, supplied by the Committee on
the Physiological Effects of Food, Training, and Clothing on the
Soldier, that in proportion to their respective body weights the
Japanese were more abundantly fed than the Russian soldier in
Manchuria or the British in South Africa.

We may now refer in detail to the dietary study Oshima
records with a jinricksha man, as its counterpart will be found

THE PROTEIN METABOLISM OF MANKIND 75

when we come to examine the dietary of the dandy carriers of
Darjeeling. This man was thirty- three years old, and weighed
62-4 kilos. His work was very laborious, and consisted in
drawing his ricksha with one man in it anything from fifteen to
thirty miles daily. The ricksha men often run long distances
with heavy passengers ; a not uncommon run is from Tokyo to
Nikko, a distance of sixty-eight miles, which they will cover in
fifteen hours.

This is an example of those classes who are held up by vege-
tarians as demonstrating the wonderful results that can be
obtained by a simple vegetable diet, as the usual impression
conveyed is that these feats of strength and endurance have been
performed on a few handfuls of boiled rice.

The diet of this man supplied 158 grammes of protein and a
fuel value of 5,050 calories, and was both abundant and varied.
It is particularly worthy of note that 41-1 per cent, of the total
protein in the diet was derived from an animal source. Contrary
to the popular belief, these jinricksha men spend a comparatively
large part of their income on animal food. Tiegel states that
they eat large quantities of rice during their working periods,
but during the periods of rest they consume large amounts
of fish, eggs, beef, and pork. He states that there has been a
considerable degree of misrepresentation with regard to the
amount of protein in the diet of these people.

The class in India corresponding to the jinricksha man of
Japan was found to live on a protein intake of 175 grammes, of
which well over 60 per cent, is derived from an animal source —
in fact, these men eat from 20 to 30 ounces of beef or mutton
daily.

A comparison of the conditions met with in this Japanese
jinricksha man with those found for men engaged in similar work
round Darjeeling is of interest.

The Japanese metabolized 0-35 gramme nitrogen, and expended
almost 81 calories per kilo of body weight. He absorbed 137-1 of
the 157-6 grammes of protein offered in his diet.

It was computed that the Indian dandy walla — average
body weight 60 kilos — metabolized 0-35 grammes nitrogen
(probably too low an estimate),* and expended about 100 calories
per kilo of body weight, the fuel value of his diet working out at
over 6,000 calories.

* Scientific Memoirs, Government of India, No. 37, p. 216.

74

THE PROTEIN ELEMENT IN NUTRITION

studies under the same conditions as nearly as possible in
America :

Dietary Studies.

Protein.

Fuel Value.

Grammes.

Calories.

Professional and business men :

Average of 13 studies

87

2,190

Professional men in United States :

Average of 14 studies

104

3,220

Medical students (Japanese) :

Average of 8 studies . .

98

2,800

Military cadets (Japanese) :

Average of 1 1 studies
College clubs in United States :

113

3,185

Average of 15 studies

107

3,580

Hard labour :

Rice-cleaner (Japan)

110-5

4,107

Jinricksha man (Japan)

158

5,050

Coal-miner (Japan)

145

2,660

Football team (United States)

226

6,590

Japanese Army :

Average of 261 studies

124

3,360

Japanese Navy :

Revised (1900) allowance, peace

151

3,250

American Navy

145

4,280

With regard to the army ration, when the weight of the soldiers,
which is undoubtedly less than that of European troops, is taken
into account, it will be seen to compare very favourably with the
protein content and energy value of the dietaries of the British
Army. Thus —

Army Rations.

Protein.

Fuel Value.

Average food supplied gratis to four
regiments
British soldiers in detention, withou
labour

British
b hard

Grammes.

133
127

Calories.
3,369

3 272

British Army minimum war ration
Africa)

(South

138

3,903

Russian Army war ration (Manchuria). .
Japanese Army war ration (Manchuria)

187
158

4,891
4,343

It is evident from these figures, supplied by the Committee on
the Physiological Effects of Food, Training, and Clothing on the
Soldier, that in proportion to their respective body weights the
Japanese were more abundantly fed than the Russian soldier in
Manchuria or the British in South Africa.

We may now refer in detail to the dietary study Oshima
records with a jinricksha man, as its counterpart will be found

THE PROTEIN METABOLISM OF MANKIND 75

when we come to examine the dietary of the dandy carriers of
Darjeeling. This man was thirty- three years old, and weighed
62-4 kilos. His work was very laborious, and consisted in
drawing his ricksha with one man in it anything from fifteen to
thirty miles daily. The ricksha men often run long distances
with heavy passengers ; a not uncommon run is from Tokyo to
Nikko, a distance of sixty-eight miles, which they will cover in
fifteen hours.

This is an example of those classes who are held up by vege-
tarians as demonstrating the wonderful results that can be
obtained by a simple vegetable diet, as the usual impression
conveyed is that these feats of strength and endurance have been
performed on a few handfuls of boiled rice.

The diet of this man supplied 158 grammes of protein and a
fuel value of 5,050 calories, and was both abundant and varied.
It is particularly worthy of note that 41-1 per cent, of the total
protein in the diet was derived from an animal source. Contrary
to the popular belief, these jinricksha men spend a comparatively
large part of their income on animal food. Tiegel states that
they eat large quantities of rice during their working periods,
but during the periods of rest they consume large amounts
of fish, eggs, beef, and pork. He states that there has been a
considerable degree of misrepresentation with regard to the
amount of protein in the diet of these people.

The class in India corresponding to the jinricksha man of
Japan was found to live on a protein intake of 175 grammes, of
which well over 60 per cent, is derived from an animal source —
in fact, these men eat from 20 to 30 ounces of beef or mutton
daily.

A comparison of the conditions met with in this Japanese
jinricksha man with those found for men engaged in similar work
round Darjeeling is of interest.

The Japanese metabolized 0-35 gramme nitrogen, and expended
almost 81 calories per kilo of body weight. He absorbed 137-1 of
the 157-6 grammes of protein offered in his diet.

It was computed that the Indian dandy walla — average
body weight 60 kilos — metabolized 0-35 grammes nitrogen
(probably too low an estimate),* and expended about 100 calories
per kilo of body weight, the fuel value of his diet working out at
over 6,000 calories.

* Scientific Memoirs, Government of India, No. 37, p. 216.

76 THE PROTEIN ELEMENT IN NUTRITION

Reference may here be made to the very satisfactory results
that followed on an increase in the supply of protein in the
Japanese Navy dietary in 1884. The principal changes were the
substitution of bread for a large part of the rice and a large
increase in the amount of protein of animal origin.

The following statistics show the improvement in health that
followed on the change of diet :

1878-1883, of 29,321 marines, 9,316, or 32-5 per cent., had beri-beri.

1884,1 (718.1

1 ftftf^ I ' 1 .4.1 I

188f I 48,275 ,, „' rOt 1-6 per cent., had beri-beri.

1887-1889 J 1 3j

The proportion of other diseases was also very materially
decreased. It is not to be wondered at, in the light of these
results, that the problems of nutrition attracted great attention
in the Navy.

INVESTIGATIONS IN INDIA.

We may now take into consideration such information as is
available regarding the dietaries of the inhabitants of tropical
countries, and the level of nitrogenous metabolism attained.

Study 1. — The first study* carried out was on students and
servants of the Medical College, Calcutta. The aim of the
investigations was to obtain some idea of the average quantities
of the more important constituents present in the urine of the
natives of Calcutta with whom there was free choice of food.

The only point at present necessary to consider is the elimina-
tion of nitrogen shown by these observations. Over two hundred
analyses were made, and on an average the amount of nitrogen
excreted in the urine was just under 6 grammes per man daily.
In these observations the subjects of the inquiry had a perfectly
free choice of food, and their several conditions in life corre-
sponded in every way to that of the great majority of the popula-
tion of the rice-eating inhabitants of India. The excretion of
6 grammes of nitrogen in the urine would correspond to the
metabolism of 35-5 grammes of protein daily, which, even after
making allowance for the elimination of metabolized nitrogen
in all other secretions and excretions, would mean a very low
level of nitrogenous metabolism. Accepting an average of
75 per cent, for the absorption of the protein of these dietaries,
even under the most favourable circumstances, the average rice-

* Scientific Memoirs, Government of India, No. 34, p. 4.

THE PROTEIN METABOLISM OF MANKIND 77

eating Bengali does not obtain more than 55 grammes of
protein in his daily food. The nitrogenous metabolism per kilo
of body weight of the students and servants examined works
out at 0-116 gramme ; the average weight of the Bengali, based
on about 30,000 weighments, being 50 to 50 \ kilos.

It may be pointed out that, so far as information is available,
the rice-eating Bengali lives on a poorer protein supply than
any of the other races on whom investigations have been carried
out. Oshima's observations on the poorer classes in Japan show
that the protein metabolism they attain is higher than in the case
of the Bengali. In connection with this it is worthy of note that,
although the Japanese are considerably smaller in stature than
the average Bengali, the average weight of the Japanese is
54 to 56 kilos, whilst that of the Bengali is only about 50 kilos.

The poorer classes in Japan metabolize 0-177 gramme of
nitrogen, whilst the average Bengali shows under 0-12 gramme
of nitrogen undergoing metabolism per kilo of body weight. If
the relative extent of surface of the two types be taken into
account, the conditions will be found to be still more favourable
to the Japanese than would appear from the above comparison.

To obtain anything approaching this low level of protein
exchange within the body, it is necessary to have recourse to
the feeding experiments carried out by Chittenden ; so that
the Bengali exemplifies on a large scale the experimental con-
ditions Chittenden had to manufacture. From the results of
his investigations Chittenden states that the metabolism of
0-12 gramme of nitrogen per kilo of body weight per man daily is
quite sufficient to satisfy all the demands of the body for protein.

This is a subject that will require careful consideration later
in this volume ; at present it is only necessary to point out that,
as the Bengali practically conforms to the standard laid down
by Chittenden, he should therefore exhibit those " many
suggestions of improvement in bodily health, of greater efficiency
in working power, and of greater freedom from disease, in a
system of dietetics which aims to meet the physiological needs
of the body without undue waste of energy and unnecessary
drain upon the functions of digestion, absorption, excretion, and
metabolism in general ; a system which recognizes that the
smooth running of man's bodily machinery calls for the exercise
of reason and intelligence, and is not to be entrusted solely to
the dictates of blind instinct or to the leadings of a capricious

78

THE PKOTEIN ELEMENT IN NUTRITION

appetite."* None of these desirable results from the effects
of a low protein dietary are to be discovered in the Bengali,
and this holds, despite the fact that excessive nitrogenous inter-
change has in all probability never been a feature of the meta-
bolism of the rice- eating people of Bengal.

Study 2. — A dietary study was carried out, the subjects
being two medical assistants in the Physiological Department
of the Medical College, Calcutta, in which a careful record was
kept of the total nitrogenous intake and output. These men
had a free choice of food, and the dietaries were mixed in type,
although the amount of animal food was small.

The results obtained were —

Average Nitro-
gen Intake.

Body Weight.

Nitrogen
Output.

Nitrogen
Balance.

Nitrogen per
Kilo of Body
Weight.

8-63 grms.
10-56 „

61-6 kilos
50-5 ,,

8-43 grms.
10-43 „

0-20 grm.
0-13 „

0-112 grm.
0-169 „

These dietaries offered 53-9 and 65-9 grammes of protein
respectively in the daily food, which was as nearly as possible
the ordinary amount consumed by these men from day to day.
The subjects of the investigation were well educated, and were
in fair circumstances, so that they were not severely handicapped
by financial conditions in their choice of food. The quantity
of protein available in their dietaries is very little higher than
that calculated for the students and servants of the college.

Study 3. — The following different scales of dietary { are those
ordinarily in use amongst the different classes in Bengal, accord-
ing to their financial and social status :

DIET I. — CULTIVATORS.

Average Diet.

Approximate Value :
Principle.

Proximate

Calories.

Rice . .

20ozs,

Dal

1 oz.

Protein

52 grms.

1

Vegetables
Fish

4 ozs. f
1 oz.

Carbohydrates
Fat

475 „
25 „

Y 2,390

Oil

1 « J

* Chittenden, " The Nutrition of Man," p. 228.
t Scientific Memoirs, Government of India, No. 34, p. 36.
I Collected by Assistant-Surgeon Lai Mohan Ghosal, Physiological Depart-
ment, Calcutta. " Food and Drugs." 1910.

THE PROTEIN METABOLISM OF MANKIND

79

DIET II. — MIDDLE CLASSES (NOT ABOVE INDIGENCE).

Average Diet.

Approximate Value :
Principle.

Proximate

Calories.

Rice

16 ozs.^

Dal

Vegetables
Fish
Milk

1 oz.
4 ozs. 1
1 oz. f
4 ozs.

Protein
Carbohydrates
Fat

50 grms.
400 „
50 „

1 2,310

Oil

1 oz. J

DIET III. — MIDDLE CLASSES (ABOVE INDIGENCE).

Average Diet.

Approximate Value : Proximate
Principle.

Calories.

Rice . . . . . . 6 ozs. '
Wheat flour . . 6 ,,
Dal . . . . . 1 oz.
Vegetables . . . 4 ozs.
Fish ... . .. 2 ,,
Milk 8 „
Butter . . . 1 oz.
Oil 1 „
Meat and eggs are also added. ,

Protein . . . . 70 grms.
Carbohydrates ..300 „
Fat .. ..90 „
Protein varies with the quan-
tity of animal material
consumed

i 2,350

DIET IV. — WELL-TO-DO PEOPLE.

Average Diet.

Approximate Value : Proximate
Principle.

Calories.

Rice 4 ozs. »

Wheat flour .. 6 ,,
Dal \ oz.

Vegetables . . . . 4 ozs.

T7I- L. A

Protein, 85 to 100 grms., de-
pending on the amount of
meat and eggs

2-950

-bisn . . . . . . 4 ,,
Milk 16 „
Butter .. .. 4 ,,

Carbohydrates, 300 to 400
grms., depending on the
amount of sweets

• to
3-450

Oil . . . . . . 1 oz.
Meat and eggs are eaten, also

Fat . . . . 150 grms.

sweets freely J

The diet varies considerably according to the choice of food,
but it may be taken as very liberal in all its elements.

80

THE PROTEIN ELEMENT IN NUTRITION

DIET V. — STUDENTS LIVING IN PRIVATELY MANAGED MESS-HOTJSES.

Average Diet.

Approximate Value : Proximate
Principles.

Calories.

Rice . . 12 ozs. }
Dal . . 1 oz.
Vegetables 4 ozs.
Fish.. 2 „
Milk.. 4 „
Butter 2 ,,
Oil .. 2 ,,
Meat and eggs are also added,
but not to a great extent ,

Protein . . 55 grins.
Carbohydrates . . 325 ,,
Fat .. ..90 „

1 2,400

DIET VI. — STUDENTS IN GOVERNMENT HOSTELS.

Average Diet.

Approximate Value : Proximate
Principles.

Calories.

Rice . . 16 ozs. '
Dal .. 2 „
Vegetables 4 ,,
Fish . . 1 oz.
Butter 1 „
Oil .. 1 „
Meat twice a week

Protein . . . . 67 grms.
Carbohydrates .. 550 ,,
Fat .. ..60 ,,

I 3, 150

As would be expected, the protein and fat constituents of these
dietaries are lowest in the cases of the poorest classes, and
highest in the case of well-to-do people ; while the opposite is
the case in the carbohydrate element. It will be noticed that
fish and milk enter into the composition of all the dietaries ;
even the poorest cultivator is usually able to obtain a small
amount of milk daily. Fish the Bengali is particularly fond of,
and, owing to the large number of rivers, tanks, pools, and nullahs,
a large supply of fish is always available at a moderate price,
or for the catching.

Taken in conjunction with the results obtained from the
observations made on students, servants, and medical assistants,
the above dietaries may be accepted as representing faithfully
the average food consumption of the people of Bengal according
to their particular circumstances. These dietaries have been
given in full detail for two reasons : first, to show that wherever
possible the Bengali prefers a mixed type of dietary to a purely
vegetable kind, and that milk and fish may be taken as common
articles of food even amongst the poorer classes.

THE PKOTEIN METABOLISM OF MANKIND 81

The second and more important reason is to clear up a mis-
conception into which Chittenden appears to have fallen with
regard to the dietary of the mass of the people of Bengal. In his
very interesting and instructive paper on the merits of a low
protein dietary, read before the Therapeutic Section at the
last meeting of the British Medical Association, Chittenden,*
whilst admitting the poor physique of the Bengali, his lack of
good health, want of vigour, and poor capacity for manual
labour, and low resistance to disease and infection, attributes
these characteristics not to his poor supply of protein, but to
the character of the food.

In proof of this he quotes extracts from the memoirs dealing
with the work done on the metabolism of the Bengali and on the
gaol dietaries of Bengal. In the greater part of these extracts it
was the gaol dietaries that were being criticized and not the
dietary of the people in general.

The full gaol diet for Bengali prisoners is —

Rice .. 26 ozs.} ("Protein .. 93 grms.^

Dal .. 6 „ [ = \ Carbohydrates 693 „ ^ = 3,500 calories,

Vegetables 6 ,, J [Fat .. .. 30 „ J

of which only about 50 to 55 per cent, of the protein is absorbed.
It is with regard to the ill-balanced proportions of this type of
diet that the following criticism applies : " Simply as a means of
providing fuel for the system there is a very heavy wastage, while
the constant fermentation and putrefaction made possible by
the copious nitrogenous residue in the alimentary canal must
form a source of chronic irritation to the mucous membrane of
the bowel, predisposing to intestinal catarrh, diarrhoea, etc.
At the same time, the products of the putrefactive micro-
organisms on absorption lower the general vitality, causing
anaemia, toxaemia, and many other symptoms of ill-health."
Chittenden justly asks what bearing have these results on the
merits of a proper low protein intake where the diet is well
balanced, and shows a reasonable degree of digestibility and
availability ?

The answer is simple enough. Accepting Chittenden' s criterion
— the loss of nitrogen in the faeces — of an ill-balanced, non-
physiological dietary, the facts obtained from a study of the
people of Bengal do not support his explanation of the poor
physique of the rice-eating Bengali. Thus the results obtained

* Chittenden, British Medical. Journal, September 23, 1911, p. 661.

6

84 THE PROTEIN ELEMENT IN NUTRITION

simply represents the average amount of the nitrogen of the urine,
and that no allowance has been made for the nitrogen which has
undergone metabolism, but leaves the body in other ways than
in the urine, or that has been retained owing to an increase of
body weight. The figures given in columns 4 and 5 are, there-
fore, probably too low.

By making use of the coefficients of protein absorption given
these can be corrected. Taking the average for the six subjects,
the figures given by Chittenden and the corrected figures would
read :

Average of Figures.

Intake of
Nitrogen.

Intake of
Protein.

Nitrogen
Metabo-
lized.

Protein
Metabo-
lized.

Utilization
of
Nitrogen.

Grms.

Grms.

Grms.

Grms.

Per Cent.

As given

12-02

75-12

9-16

57-25

88-66

Corrected

12-02

75-12

10-66

66-62

88-66

There was, therefore, on the average 1-5 grammes of nitrogen,
or 9-37 grammes of protein — the difference between Chittenden's
and the corrected figures — daily for each subject metabolized,
and either retained within the body — the subjects all show a gain
in weight — or eliminated in some other way than in the urine ;
probably it disappeared to some extent in both these ways.

The important point, however, from our present standpoint
is the average amount of the faecal nitrogen shown by these six
subjects during the period of observation. Accepting the
corrected figures as properly interpreting Chittenden's meaning,
the average amount of nitrogen lost in the faeces works out to be
1 -36 grammes per man daily. The importance of this lies in the
fact that Chittenden attributes the poor physique of the Bengali
to his " unbalanced, unphysiological ration," the criterion of
which would appear to be that 1-5 grammes of its contained
nitrogen passes through the intestinal tract unabsorbed ; whereas
the well-balanced, physiological dietary of Chittenden's six
subjects, during the use of which most satisfactory results were
obtained, allows 1-36 grammes of its nitrogen to pass out of the
body unchanged. That a difference of 0-14 grammes of nitrogen
in the daily fasces could have such far-reaching consequences
is scarcely credible, or that it can constitute the difference between
a well-balanced, satisfactory diet and an ill-balanced, inferior
diet is absurd. In this connection we may refer to the results

THE PROTEIN METABOLISM OF MANKIND 85

given by Chittenden for the excretion of nitrogen in the faeces,
and the absorption of protein in the experiments on his second
group of subjects — soldiers of the Hospital Corps.* The figures
show that many of the individuals excreted up to 2 grammes of
nitrogen per day in the faeces, and absorbed less than 75 per cent.
of the total protein offered. Yet, according to Chittenden, this
was a well-balanced diet. Indeed, it was on the results obtained
from this and similar experiments that he has based his well-
known views on economy in nutrition.

It is evident, therefore, that so far as the actual amount of
nitrogenous waste is concerned, the dietary of the people of
Bengal compares very favourably with that made use of by
Chittenden in his prolonged experiments, and that an ill-balanced
character of the Bengali ration will not explain his poor physical
attainments and other characteristics of malnutrition.

Study 4. — Three diets may be included in this study : one for
Bengalis in a residential Government college, and two for
Anglo-Indian and Eurasian students in Government colleges.
As there will be occasion to deal with the effects of these dietaries
in another connection, it will be sufficient at present to record
their values :

DIET I. — BENGALI STUDENTS (RESIDENTIAL COLLEGE).

Protein . . . . 67-11 grins. )

Carbohydrates .. 548-73 ,, \ Heat value .. 3,190 calories.

Fat ...... 71-55 „ J

Of the protein element, about 13 per cent, was derived from
an animal source.

DIET II. — ANGLO-INDIAN AND EURASIAN STUDENTS (RESIDENTIAL COLLEGE).

Protein .. .. 87-56 grms^

Carbohydrates .. 376-53 ,, > Heat value .. 2,415 calories.

Fat ...... 54-75 ,, J

Of the protein element about 55 per cent., or 48-2 grammes,
was derived from an animal source.

DIET III. — ANGLO-INDIAN AND EURASIAN STUDENTS (RESIDENTIAL COLLEGE).

Protein . . . . 94-97 grms. )

Carbohydrates .. 467-00 ,, j- Heat value .. 2,830 calories.

Fat ...... 56-20 ,, J

Of the protein element about 42 per cent., or 40 grammes,
was derived from an animal source.

* Chittenden, " Physiological Economy in Nutrition."

86 THE PROTEIN ELEMENT IN NUTRITION

Study 5. — Dietaries of the hill-tribes of Bengal.

Very accurate information was collected on the quantity and
classes of food materials consumed by these hill-men under
natural conditions. The investigations carried out and the
effects noted will necessitate detailed consideration in connection
with the relationship of food to physical development ; at present
we may simply record the dietaries.

DIET I. — TIBETAN BHTJTIAS, BHOTAN BHUTIAS (DANDY CARRIERS, RICKSHA
MEN, AND COOLIES WHO PERFORM THE HARDEST WORK).

Protein, 175 to 200 gnns. Heat value, 6,300 to 6,500 calories.

Of the protein element well over 60 per cent, is derived from
an animal source. It is not uncommon to find these men eating
as much as 2 pounds of meat daily. They are well paid and
live generously. Physically they are splendid specimens of
well-developed muscular manhood. As already mentioned, they
correspond to the ricksha men of Japan, and, like them, they
exhibit a great weakness for a liberal supply of food, and particu-
larly for animal protein.

DIET II. — TIBETAN LAMAS (PRIESTS AND THOSE WHO HAVE NOT SUCH HARD
WORK AS THE DANDY CARRIERS).

Protein, 160 to 180 grms. Heat value, 4,000 to 4,250 calories.

DIET III. — GENERAL DIET OF THE MORE POORLY-FED CLASSES WHO EARN

LOWER WAGES.

Protein, 150 to 160 grms. Heat value, 3,250 to 3,500 calories.

DIET IV. — DIET OF SIKHIM BHUTIAS (HARD -WORKING CLASSES).
Protein, 130 to 140 grms. Heat value, 3,200 to 3,300 calories.

DIET V. — DIET OF LEPCHAS (POORER CLASSES OF SIKHIM BHUTIAS).
Protein, 112 to 125 grms. Heat value, 3,500 to 3,800 calories.

In all these dietaries a large part of the protein comes from
beef or mutton, up to 70 per cent., except in Diet V., the poorer
classes of Lepchas not being able to afford more than J pound
of meat daily, which provides about 50 per cent, of the total
protein of their dietary. Bice also enters more largely into the
diet of the Lepchas.

DIET VI. — DIET OF THE NEPALESE CHUTTRIES.

Protein, 120 to 130 grms., of which less than 40 per cent, is derived from an
animal source.

PLATE 11

((I.) A GROUP OF RICE-EATING OORIYA CHILDREN

(&.) A GROUP OF BETTER CLASS OOR1YAS.

THE PROTEIN METABOLISM OF MANKIND 87

The Nepalese also eats largely of the better-class cereals — wheat,
maize, and good millets.

DIET VII. — NEPALESE CULTIVATORS (COOLIES OF POORER CLASSES).
Protein, 110 to 115 grins. Heat value, 3,000 to 3,200 calories.

Only a small percentage of the protein is derived from an
animal source, usually 8 ounces of meat once or twice a week.

These dietaries, contrasted with those of the rice-eating
Bengali, are very superior not only in the gross quantities of
protein consumed, but also in the manner in which the total
protein is made up. They serve to illustrate the general law,
that where there is free choice of food, hard muscular labour
demands a liberal supply, and insists, when financially possible,
on a generous proportion of an animal protein in the daily
dietary.

As might be expected, the dietaries of these hill-tribes permits
of a high level of nitrogenous interchange. From the results of
investigations the following conclusions were arrived at with
regard to the degree of protein metabolism* obtained with
different dietaries :

Nitrogen Metabolized per
Kilo of Body Weight.

Nepalese Bhutias 0*42 grm.

Tibetan and Bhutan . . 0-35 ,,

Sikhim Bhutias 0-25 „

Nepalese 0-18 to 0-25 grm.

Anglo-Indian and Eurasian students . . . . 0*196 grm.

Other Anglo-Indian and Eurasian students .. 0-203 ,,

Bengal students (residential Government hostel) 0-148 ,,

Bengali students (private messes) .. .. .. 0-116

Students and servants . . . . . . . . 0-111 to 0-115 grm.

Two Bengali assistants . . . . . . . . 0*137 grm.

Beharis 0-145 ,,

These results should be contrasted with those obtained
on —

Nitrogen per Kilo of Body

Weight Daily.
Scientific workers (Chittenden)

Members of the Medical Corps (Chittenden)

Athletes (Chittenden)

Poorer classes in Japan (Oshima)
Average European (Voit)

0-12 to 0-13 grm.

0-177 grm.
0-270

The significance of these results on physique and the general
well-being of the body will be discussed in another connection.

* Scientific Memoirs, Government of India, No. 37, p. 222 ; also Memoir,
No. 34.

THE PROTEIN ELEMENT IN NUTRITION

At present it will be sufficient to point out the close similarity
that exists between the quantity Chittenden has found amply
sufficient to meet all the protein needs of the body and the average
level of nitrogenous interchange in Bengalis.

Study 6. — An inquiry was made into the dietaries of the
aboriginal tribes of Chota Nagpur in Bengal. The facts obtained
go far to corroborate the finding of Dr. Harry Campbell as to
the mixed form of alimentation shown by those races who have
not yet reached the stage of cibiculture.

Some of these tribes have begun to cultivate the ground and
raise crops ; some, on the other hand, live on what they can obtain
without agriculture. The more highly civilized and Hinduized,
such as the Pators and Sawanis, do not eat cow, buffalo, or pig ;
the Mundas and Uraons of Dravidian extraction eat all kinds
of flesh, including rats, snakes, insects, jackals, pigs, lizards, etc.
— in fact, anything they can catch.

The Pators and Sawanis eat all other kinds of flesh, except
that forbidden by the Hindu religion, and are particularly fond
of goat. The Sawanis do not possess any land to rear goats,
so that they have developed into a caste of professional thieves,
the principal thing stolen by them being goats, which they
promptly eat.

As the Mundas practically never milk their cows, infants
who lose their mothers have a very poor chance of surviving.

The Todas, a pastoral tribe in the Nilghiri Hills of Southern
India, are of more than ordinary interest from a dietetic stand-
point. They are totally unacquainted with vegetable food,
and live entirely on milk and buffalo meat or other animals that
they can capture. They know nothing of salt, and have no
desire for it. In this respect they exhibit the same character-
istics as carnivora elsewhere. It has been shown, indeed, to be
a universal rule that in all times and in all lands those people
who live entirely upon animal food either never have heard of
salt, or, if they possess salt, avoid it ; whereas the people whose
staple food is vegetable, have the greatest desire for salt, and
regard it as an indispensable article of diet.* The Bushmen
of South Africa live by the chase, and do not use salt. Similarly,
the Kirghese live on meat and milk ; the Bedouins in Arabia
live on meat ; the Indians of North America, hunters and fisher-
men ; the shepherds of the South American pampas, who live

* Bunge, " Physiological and Pathological Chemistry "

THE PROTEIN METABOLISM OF MANKIND 89

entirely on meat and regard vegetable food as fit only for animals
— none of these make use of salt, although there is no scarcity
of it in any of these places.

It will be evident, therefore, that the aboriginal tribes of
Chota Nagpur live on a mixed diet, a large part of the protein
constituent of which is derived from an animal source. Taking
the average of the dietaries investigated, over half the protein
is provided by the animal kingdom in one or other form. The
following is a fair average of the food consumption :

Average Diet.

Approximate Value.

Proximate Principles.

Calories.

Rice . .

20 ozs.^i

Dal

Vegetables
Meat

2 „
6 „ }
6

Protein . . 80 grms. j
Carbohydrates .. 500 ,,
Fat .. .. 50 „ J

2,800

Milk

4 „ J

Of the total protein about 35 grammes is derived from an
animal source. It will be noticed that meat forms a much larger
part of the dietary than is the case with the inhabitants of the
plains of Bengal. On the other hand, there is a smaller quantity
than that found to be present in the dietaries of the hill-tribes
of Darjeeling.

Of the 80 to 85 grammes of protein, 60 grammes are absorbable,
which would mean the metabolism of 0-17 grammes per kilo of
body weight. This is a considerably higher level of nitrogenous
interchange than the Bengali attains, and brings these aborigines
up to about the standard of the poorest Nepalese.

Study 7. — A considerable amount of information was collected
with regard to the food and dietaries of the fighting castes of
the United Provinces and the Punjab. In these provinces rice
is no longer the staple foodstuff, its place being taken to a large
extent by wheat amongst the better-fed classes, and by maize
and the different millets amongst the poorest classes. As might
be expected, the dietaries of the good-fighting tribes are very
superior to those of Behar or Lower Bengal. The superiority
is largely due to the substitution of wheat and maize for rice.
Good-class wheat contains up to almost twice as much protein
as rice, and its protein shows a very much higher coefficient
of absorbability. In the food consumption of the races from

90

THE PROTEIN ELEMENT IN NUTRITION

which the best material is obtained for the Indian Army, a con-
siderable quantity of animal matter has a place. Milk and its
various preparations form very important elements of the
dietary with all classes.

As we shall have occasion to discuss the dietaries of these
fighting tribes and the results seemingly obtained from them in
another connection, it will be sufficient at present to give the
food consumption of the Sikh — one of the most widely known
of the fighting races of India.

1. As children. They, like most of the children of India, are
breast-fed for a long period — about two and a half years. After
the first year, or year and a half, the mother's milk is supple-
mented by fresh cow's milk diluted with an equal quantity of
water. Towards the end of the period of suckling the child is
given a morning feed of curdled milk — a sort of junket- — 4 ounces
daily.

2. At two and a half years of age the child is weaned. He is
then given four meals a day, the aggregate consisting of the
following quantities of food materials, which represent the
averages up to early adult life :

Milk

Curd

Wheat

Rice

Dal

Sugar

Vegetables

Butter . .

8 ozs.*

2 t

8

4

2

2

2

1 oz.

Approximate Value.

Protein, 50 to 60 gnns.

Heat value, 2,000 to 2,250 calories.

In addition, the child, at the age of three years, begins to take
meat in small quantities, usually two or three times a month.

3. Young adults living in their villages are able to obtain large
quantities of cow's milk and various kinds of animal food, such
as goat's flesh, mutton, fowls (male fowls only), venison, bacon,
eggs, ducks, pigeons, fish. The better off the family happens to
be, the greater is the average amount of animal food in the
dietary. Beef is never eaten, the cow being a sacred animal.
The average dietary is as follows :

Approximate Value.

Milk ..
Wheat
Butter
Dal . .
Vegetables .
Meat ..

16 o
24

2
3
6
4

Z8')

! Protein, 125 to 130 grms.
(Heat value, 3,750 to 4,000 calories.

* And upwards.

Morning.

THE PROTEIN METABOLISM OF MANKIND

91

Of the total protein, 35 to 45 per cent, is derived from an animal
source. The large amount of milk in the dietaries of these people
is very noticeable.

From the coefficients of protein absorption obtained for
these foodstuffs in India, the level of protein metabolism may
easily be calculated. Thus milk, butter, and meat provide
45 grammes protein, of which 43 grammes will be absorbed ; and
the cereals and vegetables provide 83 grammes, of which 75 per
cent., or 62 grammes, will be absorbed. Therefore the total
protein absorbed is 105 grammes, or 16-8 grammes nitrogen per
man daily. The average weight of the Sikh is 68 kilos, which
would mean a metabolism of 0-25 gramme of nitrogen per kilo
of body weight. These are the minimum figures.

As will be evident, the diet of the Sikhs in their own homes is
quite up to that of European standards. A minimum protein
metabolism of 105 grammes daily, equal, in the case of the
Sikh, to an interchange of 0-25 gramme of nitrogen per day,
places him on an equal footing with the better-fed races of man-
kind, and very much superior to the rice-eating Bengali, and
most of the other races of the plains of India.

It is of interest in this connection to examine the dietary of
recruits on joining their regiment. The food and quantities per
man are as follows :

Milk ..

Butter

Wheat

Dal ..

Mutton

Sugar

Vegetables

16 ozs.

2* »

26 „

3 ,,

3 „

ioz.

6 ozs.

Approximate Value.

Protein, 135 grms.

Heat value, 4,000 calories.

Besides this, recruits frequently purchase other delicacies
out of their pay. About 40 grammes of the total protein is
animal in nature, and the level of protein metabolism attained
on the above diet works out at a daily interchange of 110 grammes,
or 17-6 grammes of nitrogen per man daily. The above dietaries,
which understate rather than overstate the case, are given in
detail, as it is not uncommon to see such loose statements as the
following made : " Hindus live entirely on rice." Sikhs are
Hindus, therefore " Sikhs live on rice." " Sikhs live entirely
on vegetable food." As a matter of fact, as will be seen when
we come to examine the dietaries of the well-developed races of
Northern India, the truth is that the foodstuffs made use of are

92

THE PROTEIN ELEMENT IN NUTRITION

of excellent quality, and sufficient in quantity to render them
equal, if not superior, to the standard dietaries generally accepted
in Europe and America. Further, it may be again insisted on
that animal food in some form practically always enters into the
composition of the dietaries of the great mass of the people.
Milk is very cheap, except in the large towns, and, in its various
preparations, forms an important element even in the food of
the poorest. Ghi — butter that has been boiled and allowed to
cool — is partaken of by all except those actually in absolute
want.

Study 8. — As it is the custom in India for all mothers to suckle
their offspring for at least the first year, it is of importance to
know the composition of the Indian mother's milk. It would be
very desirable if this could be obtained for the different tribes and
races in India, and thus be able to determine if the difference in
physique, stamina, etc., so evident amongst the several races,
is accompanied by variations in the nutritive value of the infant's
food. Such differences, other things being equal, would be
expected — that is, a well-developed, well-fed mother would be
more likely to be able to secrete milk of high nutritive value
than a poorly developed, ill-fed woman. Owing to the many
difficulties blocking the way, so far as we are aware, no statistics
are available on this point. A certain number of analyses
of the milk of Bengali women were made in the Physiological
Department of the Calcutta Medical College with the following
results :*

Bengali Mother's
Milk.

European Mother's
Milk.

Protein
Carbohydrates
Fat
Minerals

1*20 per cent.
5-90
2-80
0-24

1-6 per cent.
6-5
3-5
0-2

Too much reliance cannot be placed on these differences in the
several constituents, as it is well known how great the variations
are in the composition of human milk from day to day, and
even from hour to hour, even in the same woman. However,
after making due allowance for this, it is evident that the milk
secreted by Bengali women is considerably poorer in its different
* Dr. Lai Mohan Ghosal, " Food and Drugs," 1911.

THE PROTEIN METABOLISM OF MANKIND 93

elements than the milk of the average European women. It is
also a well-recognized fact that the protein of human milk tends
to decrease in amount as lactation proceeds, and that the milk
of the mother does not get richer as the child grows older, but that
the increasing demand for nutriment by the growing infant is
met by supplying an increased quantity of milk.* It might,
therefore, be expected that the lower composition of the Bengali
mother's milk would be compensated for by the secretion of
larger quantities. Such, however, is not the case.

The requirements of a healthy infant, as observed by Camerer
and Feer, on an average is as follows :*

1st and 2nd months . . . . 600 grms. daily . . 20 ozs. daily.

2nd and 4th „ . . . . 800 „ „ . . 27 „

5th and 7th , 950 „ „ .. 32 „

7th and 9th ,, .. .. 1,020 „ „ .. 34 ,,

9th and 12th „ . . . . 1,150 „ „ . . 39 „

The average quantity of milk secreted by the European
mother being calculated to be 1J to 2 pints daily. In India,
from observations on Bengali women, the daily quantity of milk
secreted was found to be 1 to 1| pints. The daily requirements
of the infant were also tested by careful weightments of the child
before and after each feeding, with the following results :

1st to 2nd months . . . . 400 grms. daily . . 14 ozs. daily.

2nd to 4th „ . . . . 600 „ „ . . 20 „

4th to 6th „ .. .. 750 ,, ,, . . 27 „

6th to 9th „ .. .. 800 „ „ .. 28 „

9th to 12th „ .. 900 to 1,000 ,, ,,30 to 35 „

It would appear, therefore, so far as observations in India
go, that the Bengali infant is not provided by Nature with as
great a quantity of milk, nor with milk reaching the same high
standard of chemical composition, as the European infant.
This fact would appear to be a provision of Nature in providing
a supply of food in accordance with the requirements of the
infant. The average weight of the European newly born infant
may be taken at 7-4 pounds, whereas the average Bengali new-
born infant weighs 5-9 pounds at most.

The following table")* shows the average weight of new-born
infants of European and Indian mothers confined in the Eden
Hospital, Calcutta :

* Hutchison, " Food and the Principles of Dietetics."

f Leicester, Journal of Obstetrics and Gyncecology, June, 1907.

94

THE PKOTEIN ELEMENT IN NUTRITION

Number of Confinements.

Average Weight of Infant.

Variations Observed.

87 Europeans
142 natives

7-4 Ibs.

5-9 „

/Maximum, 10-56 Ibs.
\Minimum, 5*56 ,,
J Maximum, 8-27 ,,
V Minimum, 4-09 ,,

By contrasting the quantities of nutritive materials available
for a Bengali and European infant of six months of age, these
differences are clearly brought out :

Proximate Principles.

European Infant.

Bengal Infant.

Protein
Carbohydrates
Fat

14 grms.
59 „
30 „

9-6 grms.
47-2 „
22-4 ,,

From careful observations on the influence of the mother's
diet on the composition of her milk, it was found that fat is the
only ingredient of the milk on which diet produces any effect.
Baumm and Illner record a rise of 1 per cent, with a highly
nitrogenous and with a very abundant mixed dietary ; whereas
an abundant supply of carbohydrates has no influence on the
amount of fat, and an increased amount of fat eaten seems to
diminish rather than increase the amount of cream in the milk.
Observations on cows fed on a highly nitrogenous bean diet,
which produces milk greater in quantity and richer in quality
than any other diet, would afford strong evidence of the impor-
tance of the protein element in the diet of the mother in in-
fluencing the chemical composition of her milk.

The fact that the dietary of the Bengali is very poor in protein
and fat, whilst comparatively rich in carbohydrates, in all proba-
bility is sufficient to account for the differences met with in
the milk of the Bengali when contrasted with that of European
women.

The importance of an adequate supply of nutritive materials
in the food of the infant has never been called in question by even
the most rabid advocates of the superior merits of a low protein
dietary. It may therefore be accepted that the lower quantities
of the several constituents available in the case of Bengali
children will tend to be accompanied by a lesser body weight
and a slower rate of growth. This state of affairs, acting con-

THE PKOTEIN METABOLISM OF MANKIND 95

tinuously through countless generations, must eventually lead
to the evolution of a race whose individuals are relatively on a
lower scale of physical development than that of the better-fed
races of European countries. If, after the period of suckling
is over, Bengali children were given liberal quantities of the
materials on which growth depends, they might be expected to
make up the lost ground to some extent, although the general
opinion of animal breeders is against such a contention, it being
widely held amongst these classes that if a strong, well-developed
animal of whatever species is wanted, it must be well fed from
birth. As has been shown, however, the Bengali never receives
sufficient protein at any age to do much more than meet the
pressing requirements of ordinary wear and tear, so that the
excess of protein available for the growth and building up of
the nitrogenous tissues never reaches a high level.

In accordance with this chronic state of more or less nitrogenous
starvation, we find the Bengali poor in physique, very poor in
muscular tissue, the body fat at a minimum, and the average
working man absolutely incapable of prolonged or sustained
muscular efforts. The average body weight of the Bengali is
50 kilos, that of the European 65 to 70 kilos.

We may now turn from the consideration of the dietaries
themselves to the study of the effects of those dietaries, particu-
larly as regards their protein constituents.

CHAPTER V
THE PROTEIN REQUIREMENTS OF MANKIND

IN an earlier chapter we examined the twofold function of food,
and saw that it is essential for the growth and repair of the proto-
plasmic tissues, and necessary to furnish energy for the muscular
and other work the body has to perform, and yield heat for the
maintenance of the body temperature at a proper level.

Leaving aside for the present the question of mineral matters
and water, the above requirements are met by the protein
element on the one hand, and the total potential energy of the
dietary on the other. Protein alone of the constituents of a
diet is able to perform both functions ; carbohydrates and fat
are only capable of providing heat and potential energy.
Dietaries may therefore be considered from the standpoint of
the protein element and total energy or heat value. The nutri-
tive values of the fats and carbohydrates are almost proportional
to the amount of energy they can furnish ; consequently, it is
only important that the quantity of either, or both, be such that
their total energy, when added to that of the protein of a diet,
shall supply the total amount required by the body, due allow-
ance being made for the decrease in the energy value, caused
by the loss of a certain amount of the potential energy in the
corresponding urine and faeces.*

In the present connection it is not necessary to discuss in
detail the heat values of the dietaries examined, not because
they are relatively of small importance, but for the reason that
ordinarily the caloric value is quite sufficient to meet the demands
of the body, if the diet is otherwise satisfactory. Further, as in
the present volume, we are dealing more particularly with the
light that may be thrown on the problems of nutrition from
observations on the effects of tropical dietaries ; the caloric

* Benedict, " The Nutritive Requirements of the Body."

THE PROTEIN REQUIREMENTS OF MANKIND 97

value is not of such great importance as would be the case in
European dietaries. The reason for this is that tropical food,
being largely of a vegetable nature, any dietary that affords
a sufficiency of the protein element is very unlikely to be deficient
in carbonaceous material, but, indeed, will usually provide a
potential energy considerably in excess of the ordinary dietary
standard.

In connection with the work on dietaries in India, except
where the potential energy is evidently of importance, we shall
limit our consideration of the subject to the protein element.

There is just one aspect of carbon metabolism that we should
like to refer to at once, as it has impressed itself very urgently
on us whilst working with diets that provide a large fuel value,
such as the gaol dietaries of Bengal. The usually accepted state-
ments place the coefficient of carbohydrates absorption from
different foodstuffs very high — as a rule, from 96 to 99 per cent.
This result is arrived at by comparing the loss of carbohydrate,
capable of being hydrolyzed into sugar, in the faeces with the
total quantity presented in the diet. Now the Bengal gaol diets
provide, in comparison with European standards, a very exces-
sive amount of carbohydrates, sufficient in most cases to raise
the energy metabolism to 60, or over 60, calories per kilo of
body weight. Apparently the large quantities of carbohydrate
matter necessary for this great heat value are practically all
absorbed, as only a very small percentage could be recovered
from the fseces.

On thinking over the question how this great potential energy
is made use of by Bengali prisoners, we have experienced con-
siderable difficulty in accepting the customary explanation that
it leaves the body in the form of heat and mechanical work, or
is retained as fat. The ordinary working Bengali is a particu-
larly thin individual, decidedly wanting in body fat, and his
desire for, or capabilities of, muscular exertion are less than in
any other race with whom we have had to do. The large masses
of carbohydrate cannot, therefore, be burnt off in providing
energy for muscular exertion, neither can it be fixed and stored
in the body as fat. The demands for fuel for the maintenance
of body heat in a tropical country should not be anything like
so great as in colder climates ; and yet the accepted standard
for Europeans is from 40 to 45 calories per kilo of body weight,
whilst prisoners in Indian gaols are provided with 60 to 70 calories.

7

98 THE PROTEIN ELEMENT IN NUTRITION

The extremely meagre clothing of the poorer classes may create
a certain demand for easily oxidizable material in the up -keep
of the body temperature, particularly during the cold weather.

The question, therefore, arises : Seeing that a European in
a cold climate, doing an average amount of work, can live quite
well with 40 calories per kilo of body weight, whilst the Bengali
prisoner, in a hot climate, doing the very minimum of work, is
provided with 60 to 70 calories per kilo of body weight, what
becomes of the great potential energy of the dietaries ? How
does he get rid of it ? How is it dissipated ?

The answer to this question would appear to be threefold.
A part of the carbohydrate, varying in amount according to the
needs of the body, is absorbed and made use of to supply the
energy necessary for the maintenance of body heat and that
essential for the work of the body ; a part undergoes little or no
change in the bowel, and passes out undissolved. This is prob-
ably due to its being bound up with cellulose, so that the digestive
juices are unable to penetrate to the starch granules and set up
changes essential for absorption. A third part is broken up in
the digestive tract by excessive micro-organismal fermentation,
which, beginning in the stomach, is contained in the intestines.
By this last method a very large percentage of the total potential
energy of the diet may be dissipated through the conversion of
its starch or sugar into carbon dioxide, methane, hydrogen, acetic
acid, butyric acid, etc., and other fermentative products of low
caloric value.

This loss, which may be considerable in amount depending
upon the extent of intestinal fermentation, will tend to reduce
the fuel value of the diet, and may afford a likely explanation
of the remarkable want of body fat in the great majority of the
working population of Bengal. So far as we know, there is no
method by which this loss can even be approximately computed
— at least, by chemica means ; but that it is an important factor
in reducing the potential value of the food will be readily
admitted when it is considered that even with gaol dietaries,
which are exceedingly rich in carbohydrates, the storing of fat
is practically nil, whilst in the working coolie of Bengal, living in
a condition of more or less nitrogen starvation, neither body fat
nor properly developed muscular tissues are usually to be found.

It is evident from the above considerations that the ordinary
methods of determining the digestibility and absorption of the

THE PROTEIN REQUIREMENTS OF MANKIND 99

carbohydrates and fat of dietaries, may not give anything like
accurate results.

This objection does not hold when dealing with protein. The
fsecal nitrogen may be accepted as a true measure of the protein
lost to the body, whatever may be the actual form in which it is
excreted. Thus, in conditions of excessive putrefaction, the
nitrogen may be largely represented as masses of bacteria.
However, as nitrogen cannot be lost nor created in the bowel,
any change of form will have no influence on the actual quantity
present. One other point in this connection may be referred to
—viz., the nitrogen eliminated in the faeces that really has been
metabolized, but has been made use of in the formation of the
intestinal juices. There is very little doubt that vegetable
dietaries, such as those of India, require a very much greater
secretion of the several digestive juices than the ordinary mixed
dietary of Europeans, and that relatively there is a greater
loss of metabolized nitrogen from this source than should be the
case.

Strictly speaking, the nitrogen derived from the secretions
of the bowel is not really loss from the protein intake of the food,
but in actual effect it comes to exactly the same thing. Whether
the fsecal nitrogen is derived from the protein of the food or from
the intestinal secretions, it is lost so far as the body is concerned.
If a diet requires great quantities of the intestinal juices for its
digestion, a corresponding great increase in the fsecal nitrogen
from this source will be determined, and a corresponding amount
of nitrogen will be withdrawn from the body to provide the
materials necessary for the digestive secretions. We have,
therefore, in the determination of the fsecal nitrogen a true measure
of the total waste of protein corresponding to the dietary for the
period during which the investigation is being carried out. With
a knowledge of the protein intake during that period the co-
efficient of protein absorption from the food can easily be
arrived at.

Having decided that dietaries may be considered from the
view-point of their total protein and energy values, and that the
potential energy is usually sufficient, if not excessive, the only
question we are directly concerned with at present is the protein
element.

100 THE PROTEIN ELEMENT IN NUTRITION

THE PROTEIN KEQUIBEMENTS OF THE BODY.

The problem presented in determining the daily requirements
of the body for protein is one concerning which there has been
a good deal of controversy, and one to which, up to the present,
no definite solution has been furnished. Several different methods
of attacking this problem have been devised.

Thus it has been shown that, on an average, all over the world
where a sufficiency of food is available, mankind consumes at
least 100 grammes of protein daily. The Japanese and Hindus
have been regarded as notable exceptions ; but on closer ex-
amination such will not be found to be the case. Both Japanese
and Hindus make use of large, rather than small, quantities of
protein where a free choice of food can be afforded. Further,
as has been exemplified by the dietaries of the jinricksha men
of Japan, and hill-tribes of Bengal, and amongst the better-fed
classes of the plains of India, it is not simply a matter of in-
creasing the quantities of the ordinary foodstuffs consumed —
this, indeed, does take place to some extent — but, what is more
noticeable and of greater importance, is that there is a demand
for foods that are of a highly nitrogenous nature. The increasing
amounts of protein taken by different individuals when the
severity and amount of work which they are called upon to do
increases, v. Noorden explains very simply by an increase in
the amount of the ordinary food, as made use of when the work
performed is not of a severe nature. This naturally increases
the protein intake.* Whilst this may be the case in dealing
with dietaries in which the protein element is present in quanti-
ties reaching the European standards, the evidence afforded by
those engaged in hard muscular work on dietaries of the type
common to the tropics, would show that an increase of their
highly carbonaceous food materials is not sufficient to meet the
requirements of the body ; but that highly nitrogenous foods,
if possible of an animal nature, are demanded for the mainte-
nance of the musculature and power of doing work. The large
additions made to the otherwise carbonaceous dietaries of the
jinricksha men of Japan and dandy carriers of India in the form
of animal protein afford a considerable weight of evidence on
this point.

The almost universal desire of mankind for a dietary contain-

* V. Noorden, " The Physiology of Metabolism," p. 305.

THE PROTEIN REQUIREMENTS <V

ing at least 100 grammes of protein daily, despite variations in
race, country, climate, and dietetic habits, is very significant,
and has been acknowledged by most observers as conclusive
evidence of the need of at least this amount of protein. This
argument is all the more forcible and convincing in view of the
fact that all the world over protein, particularly animal protein,
is one of the most expensive constituents of the food, often
involving a good deal of labour and sacrifice to procure.

On the data furnished by freely chosen diets in different parts
of the world have been founded the standard dietaries which
have been given in detail in a former chapter. The most popular
and widely accepted of these is, perhaps, that laid down by
Voit, which provides 118 grammes of assimilable protein for an
energetic man doing a moderate amount of work. Up to com-
paratively recent times the approximate correctness of these
standards has never been called in question. They were regarded
as the minimal quantities that should enter into any well-
balanced diet, but not as bounds beyond which it was dangerous
to exceed.

It has been objected to these standards, based on the dietetic
customs and habits of mankind, that, although the consumption
of over 100 grammes of protein daily is almost universal, it
does not necessarily follow that it is to the welfare of the body.
It has been pointed out that " habits and cravings are certainly
very unreliable indices of true physiological requirements ;" that
" dietetic requirements and standard dietaries are not to be
founded upon the so-called cravings of appetite and the in-
stinctive demands for food, but upon reason and intelligence,
reinforced by definite knowledge of the real necessities of the
bodily machinery." Chittenden even goes so far as to say :
" Standards which have been adopted more or less generally
throughout the civilized world, based primarily on the assump-
tion that man instinctively and independently selects a diet
which is best adopted to his individual needs, are open to grave
suspicion. The true food requirements of the body, under any
conditions, cannot be ascertained with any degree of accuracy
by observations of what people are in the habit of eating.'"
Mankind, according to Chittenden, is guided by blind instinct
or the leadings of a capricious appetite, and eats as much of the
higher and more expensive protein food materials as he can
afford. Certainly, the only people who fail to attain the ordinary

K>2 THE PROTEIN ELEMENT IN NUTKITION

protein standard are those who are too poor to afford the cost of
the average diet ; or who, living on a very bulky vegetable diet,
are unable to consume sufficient of their foodstuffs to provide
the amount of assimilable protein present in Voit's standard.

There is little doubt, therefore, that the evidence of mankind
points indisputably to a desire for protein up to European
standards. As soon as a race can provide itself with such
amounts, it promptly does so ; as soon as financial considerations
are surmounted, so soon the so-called " vegetarian Japanese "
or Hindu raises his protein intake to reach the ordinary standard
of mankind in general.

With regard to the objections raised by Chittenden as to the
fundamental importance of the dietetic habits of mankind being
taken into consideration in determining the protein requirements,
all that need be said is that he appears to stand practically alone
in upholding this view. "It is an initial objection to Chi tt en-
den's view, which is not easily met, that it contravenes all human
experience. If he is right, then all the world up to this time,
with the exception, perhaps, of a few faddists, has been wrong.
Gluttony has somehow become universal. It is ' Chittenden
contra mundum.' "* " It is inconceivable that all mankind,
under the most diverse conditions, should have fallen into the
same mistake. Such a unanimity means no mistake, but a
physiological discovery. Natural instinct or primitive experi-
ence has guided the different varieties of our species in their
selection of viands suitable to their geographical situation and
modes of life, has restrained them within proper bounds in their
consumption of these, and has taught them to combine and
balance the different constituents of these in a way on which
chemical science can scarcely improve."*

Hutchison, in discussing the relative weight to be attached
to instinct and to greed respectively, in determining the dietetic
habits of mankind, says that there is at least strong a priori
reason for the belief that, in matters of diet, what has been
adopted semper et ubique et ab omnibus is fundamentally right.

Sir William Roberts says : " The generalized food customs of
mankind are not to be viewed as random practices adopted to
please the palate or gratify an idle or a vicious appetite. These
customs must be regarded as the outcome of profound instincts
which correspond to certain wants of the human economy.

* Sir James Crichton- Browne, " Parsimony in Nutrition."

THE PROTEIN REQUIREMENTS OF MANKIND 103

They are the fruit of a colossal experience accumulated by count-
less millions of men through successive generations . . . and are
fitted to yield to observation and study lessons of the highest
scientific and practical value."

Another method that has been put forward as a means of
determining the actual needs of the body for protein is that
based on Folin's observations on the constancy, under varying
conditions, of the output of creatinine and neutral sulphur in
the urine. Folin's work and the deductions therefrom have
already been discussed at considerable length in the introductory
chapter ; it will not, therefore, be necessary to refer to them in
detail in the present connection. It is generally acknowledged
that protein is only really essential to keep in repair the nitrog-
enous tissues of the body, and that its function of supplying heat
can be equally well undertaken by fats and carbohydrates. It
would therefore appear probable that, if the heat value of a
dietary were satisfactory owing to the presence of a sufficiency
of these two constituents, the amount of protein necessary would
only be that required to cover the loss from tissue wear and tear.
With the advent of a reliable method of estimating the katabolism
of protein involved in the disintegration of the true tissues, the
problem of the nitrogenous requirements of the body from this
standpoint would appear to be solved. Such a method has been
supposed to be forthcoming in the determination of the creatinine-
nitrogen of the urine, which has been regarded as a measure of
the endogenous or tissue metabolism.

If the nitrogen in the form of creatinine were a measure of
the katabolism- of the tissue cells, then the heat value of a diet
being sufficient, the same amount of nitrogen supplied in the
food as lost to the body in the form of creatinine should be
sufficient to meet the protein requirements of the body, make
good the loss due to true tissue change, and maintain the subject
in a condition of nitrogenous equilibrium.

The average amount of this creatinine-nitrogen is 0-6 gramme
daily, remaining, according to Folin, practically constant, whether
the diet be protein-rich or protein-free. The rational deduction
to be drawn from this argument would be, if the creatinine-
nitrogen is any measure of the protein requirements of the body,
that under the stated conditions 0-6 gramme of assimilated
nitrogen should be sufficient to maintain the body in nitrogenous
equilibrium and insure the integrity of the tissue cells.

104 THE PROTEIN ELEMENT IN NUTRITION

The fact that approximately ten times this amount of nitrogen
is necessary in a dietary in order to maintain the body in
nitrogenous equilibrium, when the caloric value of the diet is
sufficient, would show that Folin's deductions regarding the
creatinine-nitrogen as a measure of endogenous metabolism do
not cover the facts, or, if it be such a measure, then there must
be a large demand for protein in the body beyond that required
to repair tissue waste and make good its loss.

From an analysis of the more recent work on creatinine ex-
cretion, we have shown in our introduction that the small and
constant quantity eliminated daily cannot be made use of as
evidence to support the arguments of those who consider that
the protein requirements of the body would be covered by the
presence of a very limited amount of nitrogen in the daily food.

It is just possible that creatinine is a partial measure of the
nitrogenous interchanges going on within muscular tissue, and
that 0-6 gramme of creatinine-nitrogen represents to some
extent the degree of this special type of metabolism. This would
leave out of consideration the interchanges taking place between
the cells of all other tissues and the lymph, and the large supply
of fluid protein not actually incorporated into the material of the
living cell — the " labile protein " of physiologists.

In the light of recent researches on the constitution of the
protein molecule and on the demands of the tissues, not for
nitrogen merely, but for nitrogen in certain combinations, or
complexes of molecules, it is possible that, in the providing of
even 0-6 gramme of nitrogen in the form required by the muscle
cells, large quantities of protein taken in the food will require
to be broken down into their different units in order that the
suitable " building-stones " may be available in sufficient amount.
However, without an accurate knowledge of the total nitrogenous
requirements, and lacking any reliable method of determining
them, these possibilities are merely interesting speculations.
The fact that in the case of the fasting subject the excretion of
nitrogen is far in excess of the amount which, according to Folin,
corresponds to disintegrated tissue protein, would show clearly
that his deductions regarding the significance of creatinine in
the urine as a measure of the protein requirements of the tissues
cannot be correct.

An attempt has been made to arrive at the true protein
requirements of man by studying the conditions that obtain

THE PROTEIN REQUIREMENTS OF MANKIND 105

during starvation. It was thought that in the amount of
nitrogen excreted during fasting experiments there would be
obtained a measure of the quantity of protein necessary to make
good the loss from tissue disintegration. However, it is found
that excretion of nitrogen during hunger or fasting is modified
by a variety of circumstances, particularly the amount of
"labile" or circulating proteins and the condition of the body
with regard to presence of fat.

For the first few days after the withdrawal of food the excre-
tion of nitrogen is directly dependent upon the protein intake
and decomposition during the preceding days. The amount of
labile protein present in the body varies with the level of protein
metabolism during the period immediately before the fast com-
menced. If this level beforehand is high, the nitrogen output
during the first few days is large ; and if low, the output is corre-
spondingly small.

According to Voit, about 8 per cent, of the stable protein
and 70 per cent, of the labile protein of the organism are decom-
posed during starvation, the latter being completely used up
within three days. From the fourth and fifth day onwards only
stable tissue protein remains for oxidation, the labile having
disappeared. Similarly with regard to the glycogen stored in
the body, which can act as a protein sparer. It is practically
exhausted by the third day of fasting, and, as a result, the
protein metabolism, as measured by the nitrogen excretion,
shows a temporary rise. After some initial variations, the
nitrogenous katabolism in man gradually decreases during the
course of starvation. In the first ten days the nitrogen excre-
tion seldom falls below 10 grammes, but later on falls still
lower.*

An average of the results obtained from different fasting
experiments shows that the nitrogen excreted in the urine from
the fifth day of starvation onwards is about 5 grammes per day.
This amount is, however, not sufficient to supply the energy
required by the body.

It is estimated that only about 10 per cent, of the total energy
is derived from tissue disintegration, the remaining 90 per cent,
being supplied by the large store of fat present in the body when
in an ordinary condition of nutrition. So long as this store of
fat lasts the protein tissues will be drawn on mainly to meet the
* v. Noorden, " Physiology of Metabolism."

106 THE PROTEIN ELEMENT IN NUTRITION

demands of the organism for nitrogen. When the store of fat
gives out, there will be an increase in the amount of tissue break-
down, since now all forms of energy will come from the kata-
bolism of protein, and this will be accompanied by a marked
increase in the output of nitrogen — " the pre-mortal rise in the
nitrogen excretion."

Accepting the figure 5 grammes as representing the urinary
nitrogen, and allowing 0-5 gramme nitrogen for other modes of
excretion, the conclusion may be arrived at that the minimum
amount of assimilated nitrogen necessary to prevent the dis-
integration of tissue proteins is 5-5 grammes.

If this amount be given to a starving man, it will be found
that it is by no means sufficient to establish nitrogenous equili-
brium and prevent tissue breakdown. The smallest amount of
nitrogen in the food on which it is possible to establish nitrogenous
equilibrium is some three to four times the amount excreted
during starvation. If the fasting man, however, has a large
store of fat, or, if large quantities of fats and carbohydrates are
taken as food, the sparing action of these materials may be
sufficiently great to allow of nitrogenous metabolism being
maintained on quantities as small as 5 or 6 grammes of nitrogen
per day — i.e., " Man can keep the protein store of his organism
unaltered in amount on a supply of protein which lies far below
the amount decomposed during starvation."

This figure may therefore be accepted as representing the
lower limits of nitrogenous metabolism, and further decrease of
assimilable protein in the food, no matter how abundant the
carbonaceous element may be, will entail a falling back of the
organism on its own nitrogenous tissues. Numerous observa-
tions and experiments by Chittenden, Neumann, Siven, Klem-
perer, Peschal, and others, have shown that nitrogenous equili-
brium can be maintained with a diet containing about 6 grammes
of nitrogen, even when the total energy value was not excessive.
In Chittenden's experiments the potential energy was below the
ordinary accepted standards. As will be evident, also, the
inhabitants of Bengal corroborate this finding on a large scale
and over long periods of time.

For the present we may leave this point, accepting the finding
that the metabolism of about 6 grammes of nitrogen is the
physiological minimum on which mankind is able to make good
the wear and tear of his protoplasmic tissues when the demands

THE PROTEIN REQUIREMENTS OF MANKIND 107

of the body for energy are fully met by an abundant supply
of carbohydrates and fats. This amount may be regarded as
the minimum quantity of protein essential for existence, and
must be carefully distinguished from the quantity necessary to
maintain the body in the highest degree of efficiency.

By none of the methods discussed above can a definite answer
be given to the question, What are the protein requirements of
the body ? The fact that the body is ever striving to adapt
the protein decomposition to the intake, and that it can establish
itself in a condition of nitrogenous equilibrium on very varying
quantities of protein, is the great cause of the difficulties that
beset the path of those engaged in finding a conclusive reply to
the above question. This power of the organism of being able
to maintain itself in nitrogenous equilibrium on the most diverse
amounts of protein could only mean that sooner or later con-
troversy must arise as to what particular level of interchange
is best for the efficiency, economy, and welfare of the body. The
question, therefore, instead of being, What are the protein needs
of the body ? becomes, What level of protein metabolism is most
advantageous ?

As has been demonstrated at considerable length, it is the
universal opinion of those most interested in furnishing a correct
answer — viz., mankind in general — that at least 100 grammes of
protein daily is necessary if the body is to be maintained in a
condition of health and efficient for the average degree of labour
it is called on to perform ; that the protein requirement is in-
fluenced by work, hard labour demanding sooner or later an
increase in the protein constituent of the diet. Accepting for
the moment the recognized view that the energy of muscular
work comes from the carbonaceous and not from the nitrogenous
constituents of the body, the fact remains that increased labour
creates a demand for protein food. This demand is all the more
noticeable the poorer the ordinary foodstuffs are in their protein
content. In an ordinary mixed dietary this desire for protein
is met by an increase in the total amount of food consumed ;
but in tropical dietaries, which are usually highly carbonaceous,
and not infrequently bulky, a highly nitrogenous food is taken
in addition, or replaces some of the more carbonaceous materials.
This point is well exemplified by the great consumption of animal
food amongst those who do really hard labour in India and
Japan. With the mixed dietaries of Europe and America the

108 THE PROTEIN ELEMENT IN NUTRITION

desire for increased protein during hard labour is obscured, or
at least is explained away as a mere incident of the necessary
corresponding increase of food.

Physiological opinion with regard to the role of protein as
a source of energy for muscular contraction has begun to swing
back to some extent from the extreme views originally held.
Thus Liebig believed that protein was the only food capable of
supplying the energy of muscular contraction. When this was
proved not to be the case, opinion veered round to the other
extreme, and carbonaceous matter was regarded as the only
source. At the present time it is considered most likely that
muscular contraction makes no special demand on one nutritive
constituent of the food more than another, all being made use
of for the supply of the necessary potential energy. When the
deduction is made that only comparatively small quantities of
nitrogen are necessary because the body is able, seemingly, to
burn up all the protein that is given to it within twenty-four
hours ; when, similarly, the fact that the urinary nitrogen is
not found to be greatly increased during muscular excretion is
taken to mean that protein is of little or no importance as a source
of the energy of muscular contraction, we are going beyond the
facts, and beyond what is warranted in the present state of our
knowledge. All that is certain is that, on the average, quantities
of nitrogen and sulphur, corresponding closely with the quantities
of those materials absorbed from the food, are excreted within
that period. The changes that may have taken place in protein
from the time it is broken down into the hydrolyzed products of
digestion until it eventually appears in the urine as nitrogen
are absolutely unknown. It certainly appears somewhat rash
to jump to the conclusion that the great proportion of the
protein of a standard diet is of no real service to the organism,
simply because the decomposition of protein keeps pace with
the intake, and that seemingly the nitrogen absorbed from the
food is rapidly eliminated.

That protein must be taken into consideration as a source of
the energy of muscular work, leaving aside entirely its influence
on the efficiency and well-being of the body as a machine, which
influence cannot be measured and expressed in terms of so much
excreted nitrogenous waste-products, Paton's investigations
would make most probable. He found that the excretion of
nitrogen was increased both during and after the performance

PLATE III

•*< t

m

THE PROTEIN REQUIREMENTS OF MANKIND 109

of work, and the metabolism of protein indicated by the increased
nitrogen excretion amounted to 35 per cent, of the work done.
The conclusion arrived at is that " when the body contains no
stored protein, muscular exertion increases the output of nitrogen
15 per cent. ; but if the body is in good condition " — that is,
containing a store of circulating proteins — " the output of
nitrogen is larger, because such proteins are consumed as a source
of heat and energy ; but the muscle fibres are not broken down in
a greater proportion by the work they perform."*

Even if the excretion of nitrogen were entirely unaffected by
work, this would be no proof that none of the energy of muscular
contraction comes from proteins. The excretion of nitrogen
would be unaltered when proteins are oxidized within the body,
whether in the one case their energy appeared in the form of
heat, or in the other case it became diverted to muscular con-
traction.

In connection with this conception it is probable that in the
work of the body generally, and in the work of muscle in par-
ticular, protein may be made use of according to the richness
and liberality of the supply ; in fact, it is known beyond doubt
that the organism is prodigal of its protein when there is an
abundance offered in the food, and most economical when the
opposite conditions obtain. It can easily be imagined that with
a free supply of protein the interchanges taking place in the
nitrogenous tissues are ranged at a high level, the old building-
stones are rapidly got rid of, and their place occupied by others
manufactured from the amino-acids of digestion. This would
not mean any increase in the excretion of nitrogen beyond that
which would be the case on the theory that a very large propor-
tion of the protein is short-circuited through the liver, changed
into urea, and rapidly eliminated.

In the opposite condition, when the supply of protein is
eventually cut off, or greatly diminished, the tissue cells, instead
of eliminating their old or damaged building-stones, make use
of them in the best manner possible to repair the waste essential
to body work and growth, and even cut down the protein inter-
changes to the lowest possible level. This would mean that,
although during muscular exertion there may be no great increase
in the excretion of nitrogen, the tissue cells, on the other hand,

* Tibbies, " The Protein Requirement," British Medical Journal, vol. ii.,
1911.

110 THE PROTEIN ELEMENT IN NUTRITION

cannot be maintained at anything like the same high level of
nutrition as when the supply of protein is liberal. That this
view is correct would appear probable from the results of observa-
tions on the effects of establishing an animal on the lower limits
of nitrogenous equilibrium — the carbonaceous constituents of
the diet being abundant — and then causing an increase in the
work performed. The animal will soon pass from its condition
of nitrogen balance, and rapidly lose weight from the disintegra-
tion of its own tissues. In this experiment the heat value of the
diet may be exceedingly abundant, and yet the extra work
determines a disintegration of protein that cannot be met by the
amount present in the food, nor by the makeshift arrangement
of using over again the damaged building materials of the
tissue cells. In this way the increasing demands of the body
for protein during severe muscular exertion can be explained,
and the importance of a high level of nitrogenous interchange
in maintaining the tissues of the body in an efficient and
economical condition can be understood. Until more is known
concerning the changes that go on within the body from the
digestion of protein until its elimination, it is impossible to say
how much, or in what way, nitrogen is made use of in the work
of muscle or in the other nitrogenous tissues.

As Stewart has pointed out in connection with the fate of
protein within the body : " The fact that very soon after the
introduction of proteins (as well as other food substances) into
the blood the increased metabolism of them begins, is not of
itself sufficient to show that they are destroyed without being
built up into the protoplasm. For the protoplasm may have
the power of rapidly assimilating the protein in the presence of
an abundant supply, and of rapidly breaking down at the same
time."*

It may be concluded, therefore, that so far as evidence afforded
by the dietaries of mankind assists in determining the most
advantageous level of protein metabolism, it points to at least
100 grammes of protein daily as the limit below which, on the
average, nitrogenous interchange should not fall ; that when hard
muscular labour is performed, amounts considerably in excess
of this are necessary ; that the carbonaceous material of a
dietary being sufficient, the fact that a larger amount of protein
is required to maintain the body in nitrogenous equilibrium

* Stewart, " A Manual of Physiology," p. 470.

THE PROTEIN REQUIREMENTS OF MANKIND 111

when at work than when resting, points indisputably to the
importance of protein as a factor in the provision of energy for
muscular contraction. The investigations of Paton, Stockman,
Frentzel, and others afford further evidence of the important
part played by protein in muscular work, and show that severe
and excessive exercise is accompanied and followed by an
increased elimination of nitrogen in the urine.

Further, we have attempted to demonstrate that, when an
abundant supply of protein is available, the tissues, and par-
ticularly the muscular tissues, are in a position to replace dis-
integrated tissue with new material derived from the products
of tryptic digestion — an opportunity not afforded them when
the level of nitrogenous metabolism is low, in which case it is
not improbable that the tissue cells have to make use of their
old or damaged building-stones until such time as fresh material
is forthcoming. It is not difficult to imagine that under such
conditions the efficiency and economical working of the body
may suffer, as compared with the more advantageous position
which obtains when the protein metabolism is pitched at a high
level ; and this condition would be all the more marked and
exaggerated when, in combination with a low level of nitrogenous
metabolism, a high standard of functional activity is demanded,
as in severe muscular exercises. Lastly, we have referred to the
view that only a few grammes of nitrogen daily is needed, as the
speedy elimination of the nitrogen taken as food is suggested
to mean that the great proportion of it never reaches the tissues,
being split off as ammonia, changed into urea in the liver, and
rapidly excreted in the urine. While this, in all probability,
does take place to a certain extent, it is by no means proved to
occur with the greater part of the protein, and the weight of
available evidence would locate the metabolism of proteins,
as well as other food substances, within the tissue cells. It
would appear much more probable that the bioplasm possesses
the power of rapidly assimilating the products of tryptic digestion
in the presence of an abundant supply, and thus being able to
replace at once any worn, damaged, or fatigued elements, in
this way maintaining the whole mass of the protoplasmic tissues
at a high level of nutrition and efficiency. Considering the weight
of the total nitrogenous tissues of an average man, and making
allowance for a certain proportion of nitrogen probably made
use of in the form of ammonia to maintain the intracellular

112 THE PROTEIN ELEMENT IN NUTRITION

alkalinity of the liver and other tissues, the metabolism of
100 grammes of protein, or 16 grammes of nitrogen, daily would
not mean any excessive degree of tissue disintegration and
rebuilding.

In round numbers it would entail an interchange of about
1 gramme of protein in every 150 grammes of protoplasm present
in the body of the average man.

Reference has been made to the evidence afforded by the
work of Folin, Chittenden, and others, and to the conditions that
obtain during under-feeding and starvation. From the results
obtained it has been shown that the physiological minimum of
nitrogen interchange is reached when the absorption and assimila-
tion is decreased to about 6 grammes daily, the heat value of the
diet being large and almost entirely derived from carbohydrates
and fat. Folin's investigations, on the other hand, would appear
to show that endogenous or tissue metabolism of the bod}- is a
very trivial affair, requiring, if the creatinine-nitrogen of the
urine is any index, an interchange of less than 1 gramme of
nitrogen between the tissue cells and lymph. The general effect
of these observations would be to show that the average quantity
of protein consumed by mankind in his daily fare is far in excess
of the true requirements of the body. We have dealt with some
of the arguments that have been relied on, and discussed their
bearing on the point at issue. The real question to be decided
is : Can the body maintain itself in an efficient condition, as
regards its physical development, capacity for work, and resist-
ance to disease, in as satisfactory a manner on just that quantity
of protein that has been shown experimentally to be sufficient,
to establish nitrogenous equilibrium at its lowest level, or, are
larger quantities of protein, and a higher plane of nutritive
changes essential ?

The question is narrowed down to this : Accepting the view
that the energy of muscular contraction can be and is to a
considerable extent supplied by non-nitrogenous foodstuffs
and the carbohydrate moiety of the protein molecule, are we,
therefore, justified in advocating a large decrease in the protein
intake as compared with the amount arrived at in standard
dietaries ?

Is the amount of protein necessary for the repair of true
tissue waste — Folin's endogenous metabolism- — and that neces-
sary to cover the loss from external secretions, hairs, epithelial

THE PROTEIN REQUIREMENTS OF MANKIND U3

scales, etc., all that is required by the system ? If so, then a
few grammes of protein daily is all that is absolutely essential.
In other words, are we justified in believing that a diet should
contain only the minimum amount of protein on which nitrog-
enous equilibrium can be established ? If we are not justified
in this belief, and admit that an extra quantity above this
minimum is for the welfare of the body, then where is the line
to be drawn ? The question at once arises, if a small extra
amount of protein beyond actual requirements, Rubner's margin
of safety, is to the advantage of the protein- containing tissues,
will a larger quantity — an increased margin of safety — not be to
their still greater advantage ?

The answer to these inquiries can only be sought in metabolism
experiments and dietary studies not undertaken with a view of
showing the possibility of man subsisting and doing a certain
amount of work on a protein intake of one-third to one-half that
of Voit's standard, but carried out on a large scale, under varying
conditions, and over long periods of time, with the object of
determining the effects of a low protein dietary on man's bodily
and mental efficiency, susceptibility to disease, and general
well-being.

To a consideration of the evidence that has, and is being,
accumulated on this important problem we shall now turn.
Chittenden's views and the opinions of those who uphold the merits
of diets poor in protein are too well known to require detailed
exposition ; only a short synopsis, therefore, will now be given
of the work that has been done from this standpoint, reserving
for the following chapters its consideration and an account of
the results obtained by later observers.

EXPERIMENTAL RESULTS OBTAINED WITH MAN AS REGARDS THE
EFFECTS OF DIETS POOR IN PROTEIN.

There are a large number of scattered observations throughout
the literature of metabolism dealing with the lower limits of
protein intake. In the earlier experiments, when the protein
intake was small in amount, the fuel value of the diet was high,
and it was found that a large supply of non-nitrogenous food
materials allows the organism to accommodate itself easily to
a low protein dietary. Siven* was the first to reduce the energy
value of the diet to moderate proportions even when the protein
* V. Noorden, " Physiology of Metabolism," p. 300.

114

THE PROTEIN ELEMENT IN NUTRITION

intake was exceedingly low. Chittenden, experimenting on
himself, was able to maintain himself in nitrogenous equilibrium
on 37 to 40 grammes protein, and 1,539 to 1,613 gross calories
(=0-64 to 0-70 grammes protein, and 27 to 28 calories per kilo
of body weight).

The following table from v. Noorden* summarizes a few of
these observations :

Authors.

Duration of
Experiment.

Calories per
Kilo of
Weight.

Protein of
Food.

Protein per
Kilo of Weight.

Days.

Grms.

Grms.

Klemperer

8

80

33

0-50

Caspar!

5

66

49

0-71

Peschel

8

50

43

0-58

Hirschf eld

8

47

46

0-60

Siven

6

42

39

0-66

Neumann

13

40

76

MO

Chittenden

/ 6
\ 6

28

27

40
37

0-70
0-64

In practically all these experiments the conditions were
artificial, and do not correspond to those of everyday life. They
were only carried out over short periods, so that it might reason-
ably be argued that the results would not hold good for long
periods and under natural conditions.

It was reserved for Chittenden, as v. Noorden expresses it,
" to replace such laboratory experiments by a truly physiological
one on a large scale, and to furnish complete evidence in favour
of the view that a low protein intake is not only sufficient, but
efficient, for the bodily requirements."

Chittenden himself has been cited as "a monument of
fidelity " to his own views, and is certainly very greatly endowed
with the courage of his convictions. For over seven years he
has subsisted on a diet remarkable for its low level of protein
intake, and as yet without suggestion of anything but benefit
to his health and efficiency. He maintains that his health,
general physical condition, and mental power, have all alike
benefited by the change to a diet poor in nitrogen. This experi-
ment is absolutely unique, as accurate observations have been
made at intervals during this long period of years to determine
any signs of inadequacy, or any ill-effects on the health, strength,
and capacity for work. Indeed, Chittenden is disposed to think

* v. Noorden, "Physiology of Metabolism," p. 300.

THE PROTEIN REQUIREMENTS OF MANKIND 115

that he has done more work and led a more active life in every
way during the period of this experiment, and with greater
comfort and less fatigue than usual.

Two points of very great interest are brought out in the
records of these observations : one was the very complete utiliza-
tion of the daily food — the loss of nitrogen to the body per day
through the faeces amounted to only 0-79 gramme on a mixed
diet, containing a considerable quantity of matter not specially
concentrated ; the other is that this establishment of nitrogen
equilibrium on a low protein intake was accomplished without
increase in the daily intake of non-nitrogenous foods. During the
periods of six days, when the nitrogen balance was investigated,
the average heat value of the food per day was only a little over
1,600 calories.

Taking the data recorded, with an average body weight of
57 kilos, and with an average daily elimination of nitrogen for
nearly nine months of 5-7 grammes, it is evident the nitrogen
metabolized per kilo of body weight was exactly 0-1 gramme.

This is certainly a most remarkable result, even when the
facts that Chittenden's body weight is well below the average,
and that his activity was mental rather than physical, are taken
into account. Different partial explanations have been advanced
which would show that the experiment was carried out under
the most favourable conditions for a minimum intake of protein,
and for a low potential energy of the dietary. But no mental
suggestion nor simplicity in the routine of life will explain how
an average man carries on the ordinary duties of a professional
worker for a period of seven years, according to Chittenden's
latest statement, on a diet whose fuel value is only 1,600 calories,
or 28 calories per kilo of body weight, unless the average amount
hitherto considered absolutely necessary — viz., about 40 calories
per kilo of body weight — is far above the true requirements. There
are only two other possible explanations : either there is some
fallacy in the figures giving the data during the two periods of six
days each when a nitrogen balance was struck, so that they do
not accurately represent the conditions that obtained during the
whole period of observation, or, if the results obtained from
this experiment are to be extended to mankind in general, the
law of the conservation of energy as applied to human beings
must be seriously called in question.

In this connection may be pointed out the surprisingly small

116 THE PROTEIN ELEMENT IN NUTRITION

quantities of food consumed by Chittenden during the days of
the nitrogen balance. The dietaries are recorded in weights for
cooked food, but the weight in the dry condition could not have
reached more than 12 to 14 ounces daily, of which a very large
proportion consisted of potatoes and lettuce- orange salad. With
so large a quantity of vegetable material entering into the diet
during the days of observation, it is all the more noticeable how
very small the loss of nitrogen in the faeces proved to be. The
very small quantities of food taken during the days of observation
may be partly accounted for by the subject unconsciously living
more abstemiously than usual, or perhaps choosing foodstuffs
deficient in both protein and potential energy. That this ex-
planation is not improbable is brought out in the following
summary of the diet for June 23, 1904 :*

Nitrogen Value.

Total weight of cooked diet, excluding fluids drunk . . 854 grms. 6-622 grms.
Weight of potatoes, strawberries, and lettuce -orange

salad 445 „ 0-957 ,,

That is, over half the gross weight of the cooked ration is
made up of vegetable material which, as a matter of fact, is
largely water, and which only offers one-seventh part of the total
nitrogen of the diet. The potential energy of these materials is
similarly deficient. By the choice of such foods, whilst there
may be the feeling of satisfaction after a meal, the nitrogen and
energy value can be brought to a very low level. It is quite
possible, as Benedict! has shown in the case of a subject living on
about 1,600 calories, that the body was not in energy equilibrium,
but that there was an oxidation of the body fat with a reten-
tion of water, the body weight thus remaining fairly constant.

Chittenden experimented with three groups of subjects : the
first consisted of professional men doing a minimum amount of
muscular work ; the second was composed of volunteers from the
Army Hospital Corps who took a moderate amount of exercise ;
while the third group was made up of students engaged in active
athletics . The study by Chittenden on himself referred to above is
by far the most remarkable of those carried out on professional men.

The studies with thirteen soldiers from the Hospital Corps
gave results very similar to those obtained with the professional
men of the first group. The soldiers were able to maintain them-
selves in nitrogenous equilibrium on a dietary of poor protein

* Chittenden, " Physiological Economy in Nutrition," p. 43.
f Benedict and Carpenter : " Metabolism and Energy Transformations of
Healthy Man during Rest."

THE PROTEIN REQUIREMENTS OF MANKIND 117

value, the results showing that the daily excretion of the nitrogen
of the urine ranged, over a period of five months for the different
individuals, from 0-106 gramme up to 0-150 gramme per kilo of
body weight. At the same time there was no great increase in the
non-nitrogenous food — the fuel value never reaching 3,000 calories.

The third group consisted of eight students, all trained athletes.
The men were under observation for a period of five months.
No specific diet was imposed, as in the case of the soldiers of the
Army Hospital Corps, but the men willingly cut down the intake
of protein food, diminishing likewise in considerable measure
the total volume of the food for the twenty-four hours. The
results show that on an average this group excreted 8-81 grammes
of nitrogen in the urine, as compared with an excretion of from
17 to 22 grammes when the men were living on their ordinary
diet. Chittenden, again relying on the urinary nitrogen, gives
the metabolized nitrogen of these eight students as varying from
0-108 to 0-165 gramme per kilo of body weight. The potential
energy of the dietaries was not excessive — from 2,500 to 3,200
calories. It may be taken from the results of observations on
these three groups that quantities of 56, 63, and 67 grammes
protein in the diets were sufficient to maintain all these men in
nitrogenous equilibrium. These quantities only represent 48 to
57 per cent, of Voit's standard.

The following table, compiled by v. Noorden, shows the dif-
ferent points brought to light in a manner easily grasped :

Groups.

No.

Average
Weight.

Alteration
in Weight.

Duration
(Months).

Kilos.

Kilos.

Grammes. Grammes.

I. Scientific workers

5

63-6

-2-9

7-52 0-12

6to 9

II. Hospital corps

13

61-5

-1-7

7-90 0-13

6

III. Athletes

8

70-0

-3-5

8-81 0-13

5

Twenty out of the twenty-six subjects decreased in body
weight in amounts varying from 1 to 9-2 kilos, the average loss
of weight over the whole period being 2-5 kilos. The loss in
weight was probably due largely to a decrease in body fat, but
in some of the subjects there was certainly a fair degree of protein
loss due to an insufficient amount of food.

Attempts were made to show that the subjects gained in body
strength and in grace and ease in execution of movements.
Some of the members of the Hospital Corps improved in health,

118 THE PROTEIN ELEMENT IN NUTRITION

and became free from certain disorders that had previously given
trouble. From tests carried out this group showed an improve-
ment of 100 per cent, in their dynamometric records. Even the
athletes who had previously been in training showed an increase
of 50 per cent, in muscular power.

As a general summary of his experimental results, Chittenden
draws the conclusion that the need for protein food by adults may
be fully met by a daily metabolism equal to an exchange of
0-12 gramme of nitrogen per kilo of body weight, provided the
amount of non-nitrogenous food is sufficient to supply the energy
requirements of the body. Hence for an average man weighing
70 kilos, or 154 pounds, 60 grammes of protein food daily would
be amply sufficient to meet the needs of the body. " These, I
believe, are perfectly trustworthy figures, with a reasonable
margin of safety, and carrying perfect assurance of being really
more than adequate to meet the true wants of the body, sufficient
to supply all physiological demands for reserve protein, and able
to cope with the erratic requirements of personal idiosyncrasies.
It will be observed that such an intake of protein food daily is
equal to one-half the Voit standard for a man of this weight."

In corroboration of Chittenden' s findings there is the evidence
afforded by a vegetarian married couple whose metabolism was
investigated by Caspari and Glassner. The protein in the food
varied from 33 to 49 grammes per day. Hamill and Schryver,
from observations on the nitrogen excretion of scientific men in
London, found that the protein of the diet was, on the average,
about 70 grammes daily, a somewhat higher figure than Chitten-
den advocates, but considerably lower than the Voit standard.

Further, as has been shown on a large scale with regard to the
teeming millions of Bengal, the great mass of the rice-eating
inhabitants live on a protein intake that is even lower than that
advocated by Chittenden, but which provides an identical nitro-
genous metabolism per kilo of body weight — viz., about 0-12
gramme.

The most recent work* on the subject by Chittenden makes
an attempt to prove that healthy men doing a moderate amount
of work do not consume on an average the amount of protein
food called for by the ordinary standards. With a view of ob-
taining evidence on this question, he made a large number of
observations on healthy men, mostly young and vigorous students

* Chittenden, British Medical Journal, vol. ii., 1911.

THE PROTEIN REQUIREMENTS OF MANKIND 119

of the University ; some were athletic in build and tendencies,
others slender, and inclined to take little physical exercise.
The twenty-four hours' urine was collected, and the total amount
of metabolized nitrogen determined, the subject taking his usual
amount and character of food. One hundred and eight persons
were so studied. The following are the points elucidated :

Number of Students.

Nitrogen of
Urine.

Nitrogen
Metabolized per
Kilo of Body
Weight.

Body Weight.

108

Volt's standard

Grammes.
12-87
16-00

Grammes.
0-194

0'228

Kilos.
66-2
70-0

Chittenden draws the conclusion from these results that the
108 individuals selected at random from a large group of men
were plainly taking a very much smaller amount of protein food
than is generally considered essential for good health.

These men were apparently strong, healthy individuals, some
of them indulging in vigorous athletic work, while as a group
they represent the average type of vigorous manhood common
to most University centres. He asks the question : " Are we to
assume that this large group of men, taking on an average only
80 per cent, of the amount of protein food generally considered
essential for health, were all in danger of nitrogen starvation ?
Certainly, if the Voit standard of 118 grammes of protein food
represents the limit below which it is not safe for the average
man to drop ; then these individuals were living at a dangerously
low level of nitrogen intake. Are we to assume that all these
young men were unconsciously undermining their health, gradu-
ally destroying their vitality, and paving the way for the en-
croachment of disease through faulty habits of life."

We have quoted sufficiently from this interesting paper to show
the line of argument adopted, but there are several points that
appear to call for adverse criticism. These we shall deal with at
once, reserving the consideration of Chittenden' s results obtained
from his three groups of subjects for the succeeding chapter.

1 . Chittenden relies entirely on the nitrogen excreted in the
urine as a measure of the nitrogenous metabolism ; this is not
an accurate meth od . Under conditions where the diet is uniform
and does not vary from day to day, the average excretion of
nitrogen in the urine over long periods may approximate closely

120 THE PROTEIN ELEMENT IN NUTRITION

to the real nitrogenous metabolism ; but for a short period of
twenty-four hours, as in the observations on these 108 individuals,
the urinary nitrogen could not be accepted as a true measure of
the level of nitrogenous metabolism. It is well known to all
who have worked on the elimination of nitrogen in the urine that,
even with a uniform, non- varying dietary, there may be con-
siderable variations in the daily excretion of urinary nitrogen ;
the diets of these students were freely selected, and doubtless
varied from day to day.

The only true measure of the amount of nitrogen undergoing
metabolism is the difference between the nitrogen intake and
the loss of nitrogen to the body in the faeces. (The question of
the nitrogen derived from the intestinal canal that has really
been metabolized has already been discussed.)

The average quantity of 12:87 grammes given by Chittenden
as the amount of metabolized nitrogen is therefore too low, as
it makes no allowance for nitrogen that has undergone meta-
bolism, but which has either been retained or has left the body
in some way other than in the urine.

2. How are we to discover what the real average level of the
nitrogenous metabolism of these 108 subjects is ? In the latter
part of the same paper Chittenden records the results of observa-
tions on six laboratory assistants over a period of 130 days. We
have discussed this experiment already, and shown that under
fairly similar conditions these six men, with an average intake
of 12-02 grammes ot nitrogen, metabolized 10-66 grammes,
whilst only 9-16 grammes on the average appeared in the urine.
That is, 1 -5 grammes of nitrogen daily for each subject had actu-
ally undergone metabolism, but did not appear in either the
urine or faeces. If we accept this average, which is based on
Chittenden's figures, as the amount to be added to the nitrogen
of the urine in order to arrive at the real nitrogenous metabolism,
we get 12 -87 +1-50 = 14-37 grammes of nitrogen per man daily.
This works out at practically 90 grammes of metabolized protein
as contrasted with 100 grammes provided in the ordinary stan-
dard, or 90 per cent, of its protein value.

3. Voit's dietary is fixed for an average man of 70 kilos doing
an average amount of work, and provides 0-228 gramme of
nitrogen per kilo of body weight. Now, Chittenden records,
details, in the paper referred to, of 33J per cent, of the subjects
under observation ; the average body weight of these thirty-six
persons was only 61-7 kilos, so that it would be expected they

THE PROTEIN REQUIREMENTS OF MANKIND 121

could live on considerably less protein than the individual of
average physique, thus lowering the average amount of nitrogen
metabolized for the whole series. However, leaving that aside,
and taking notice only of the amount of nitrogen metabolized
per kilo of body weight, we find for the 108 students the
following facts as contrasted with Chittenden's results :

Number of Students.

Nitrogen
Metabolized.

Nitrogen
Metabolized per
Kilo of Body
Weight.

Body Weight.

Grammes.

Grammes.

Kilos.

108 (Chittenden)
108 (corrected)
Volt's standard

12-87
14-37
16-00

0-194
0-217

0-228

66-2
66-2
70-0

That is, on an average, over the whole series there is a deficiency
of 0-011 gramme of nitrogen per kilo of body weight compared
with Voit's standard dietary. Considering that this result is
obtained from a single day's collection of the urine, it must be
acknowledged to approximate very closely to the ordinary
accepted standards.

For these different reasons, it cannot be admitted that Chitten-
den has proved that these men, picked at random from a group
of several thousands, habitually live on a much smaller amount
of protein food than is called for by the commonly accepted
standards. By working out the difference as contrasted with
Voit's standard on a basis of nitrogen metabolized per kilo of body
weight, 0-217 gramme is just over 95 per cent, of the metabolism
permitted by Voit's dietary. This is a comparatively small
difference, even were it based on results arrived at by strictly
accurate methods, on which to attack the findings of physiologists
all over the world, which findings show with almost universal
unanimity that, where a free choice can be afforded, mankind
consumes sufficient food materials to provide at least 100 grammes
of protein on the average in his daily fare.

Incidentally, it shows that the subjects selected for observation,
although they were considerably below the average weight of the
normal American, only 66 kilos, the average American weighing
70 kilos, instinctively selected sufficient protein to maintain the
level of their nitrogenous metabolism at very nearly the average
height. They were not, therefore, " living at a dangerously low
level of nitrogen intake, nor unconsciously undermining their
health, and gradually destroying their vitality."

CHAPTER VI
THE MERITS AND DEMERITS OF DIETARIES POOR IN PROTEIN

IT is very generally admitted at the present time that life can
be maintained on a relatively low protein intake ; all the accumu-
lated evidence of experimental work on dietetics during recent
years would corroborate the findings of the earlier workers on
this point. Provided a certain minimum of protein be supplied,
accompanied by sufficient potential energy, a fairly active life
can be supported upon varying proportions of the three food
elements.

This is no new discovery. As Spriggs points out, " Men have
existed in the past, in the vicissitudes of wealth and poverty,
freedom, and captivity, upon dietaries as varied in both quantity
and quality as will ever be designed by experimentalists. The
main object is, therefore, not to determine upon how much or how
little a man can live, but what are the proportions of the food-
stuffs upon which he is able to maintain the body in the highest
degree of efficiency."

With regard to this latter point there is not the same agreement
of opinion. Chittenden and his followers would have us believe
that both the protein and potential energy of the usually accepted
standards can be diminished very considerably with great benefit
to the body, thus helping to increase man's greatest assets — viz.,
health, strength, capacity for work, and resistance to disease.

He further suggests that any excess of protein food over what
may be regarded as the minimum amount on which nitrogenous
equilibrium can be established, is so much waste, entailing un-
necessary labour on the part of the organism, and at the same
time exposing the tissues and organs to the possible deleterious
action of this uncalled-for excess of nitrogenous waste products
prior to their elimination from the body. The excretion of these
bodies through the kidneys is supposed by Chittenden to be a

122

CONCERNING LOW PROTEIN DIETARIES 123

special source of danger, and likely to result in permanent injury.
Chittenden brings forward evidence from the observations on his
three groups of subjects to corroborate these conclusions, and to
show how greatly the different individuals benefited during the
period when the protein intake was low.

As a general criticism, it may be said at once that there is
no evidence whatsoever that the consumption of 100 grammes
of protein is in any way injurious ; there is no relation-
ship between it and high arterial tension, arterial degeneration,
and, least of all, between it and the incidence of granular kidney.
We shall enter into this in more detail when dealing with the
conditions that obtain in the Bengali ; suffice it to say at present
that there would appear to be a far greater danger — viz., that of
malnutrition of the renal epithelium from the lowered or im-
poverished condition of the blood which accompanies, and is the
direct result of, a low protein dietary.

This lower vitality permits of invasion of the kidneys by micro-
organisms which, under healthier conditions, would have been
destroyed. Further, it may be well to point out that, according
to Chittenden's views, all excess of nitrogen and amino-bodies
beyond that necessary for endogenous metabolism — a few
grammes daily — is rapidly converted into urea by the liver, and
thus never has a chance of acting deleteriously on the organs and
tissues ; so that, on his own showing, Ihe fear of injurious effects
from the protein of diet is groundless. " Per contra," as Hutchi-
son puts it, " Chittenden has not succeeded in convincing me
that a high protein standard is not possibly beneficial by its
specific dynamic effect ; that means that it is stimulant of
metabolism that makes for vitality, and that for resistance to
disease."

The general consensus of opinion amongst physiologists and
clinicians is against Chittenden's conclusions : it cannot be said
to be proved that any benefit to health results from a low protein
dietary. In England the number of recruits refused admission
into the army is very high, many of them being in poor condition
from want of food. The poor, who suffer from defective supplies,
are generally stunted, poorly developed, and, for years after
reaching adult age, remain incapable of good bodily or mental
work.* As we shall have occasion to point out, the quality and
sufficiency of the food, and particularly a liberal allowance of

* Rowntree, quoted by Haig, British Medical Journal, vol. ii., 1911.

124 THE PROTEIN ELEMENT IN NUTRITION

protein, has a marked influence on the physical development and
welfare of a race. With regard to the protein element, v. Noorden
asks the question : " That the organism may be injured by an
overloading with the products of nitrogenous decomposition
may be true in cases of disease, but is it true for the healthy indi-
vidual ? Are the carnivora less healthy than the herbivora
because they consume a larger quantity of flesh ? The danger
resulting from the formation of toxins in the intestinal canal
when large quantities of protein are taken seems scarcely to be
founded on sufficiently strong evidence."

Chittenden's subjects all showed marked improvement in their
general health and in bodily strength ; he claims these results as
evidence of the merits of a low protein dietary. Against his con-
clusions it may be at once put forward that any healthy set of
men placed under similar conditions on a diet rich in protein,
instead of protein-poor, would, in all probability, have shown
even better results. The great objection to the experiments is
that they were carried out without controls.

The subjects were placed under almost ideal conditions for
insuring the success of the investigations : they were made to
lead regular lives ; their food was carefully chosen and properly
cooked ; there was a total abstinence from alcohol, condiments,
and indiscretions from consumption of rich foods, sweetmeats,
etc. With a carefully regulated life such as these men were com-
pelled to pursue, great improvement in health was only to be
expected. Even in diseased conditions the regular routine of a
sanatorium often transforms the bodily conditions in a compara-
tively short space of time. The 100 per cent, increase in strength
shown by the members of the Army Hospital Corps is not of any
importance further than to show that the men were in good
health. Any man on a diet above the starvation limit who prac-
tised gymnastics for one and a half hours daily for six months
would exhibit great improvement in strength, and in ease of
execution of the required tests.

Benedict, in a critical examination of the data furnished by
Chittenden regarding the absorption of protein exhibited by
these eleven men of the Hospital Corps, brings to light one very
important abnormality : During the three periods of the nitrogen
balance — six, seven, and five days — all the men lived on prac-
tically the same ration. With normal healthy men eating the
same kind and quantities of foodstuffs, practically identical quan-

CONCERNING LOW PROTEIN DIETARIES

125

titles of protein will be absorbed by each individual — i.e., the
nitrogen lost to the body in the faeces will be nearly the same in
all cases. The following are the results shown by these men :

\()

First Period : Intake,

Second Period : Intake, Third Period : Intake,

INO.

49'4 grms. N.

66'7 grms. N.

43-1 grms. N.

1

7-68 grms. N. in faeces

12-39 grms. N. in faeces

9-37 grms. N. in faeces

2

10-24

7-01

9-38

3

9-94

16-15

6-54

4

9-61

10-31

10-11

5

11-10

13-71

7-79

6

12-10

11-98

8-30

7

6-00

8-47

10-82

8

10-75

12-36

9-40

9

4-45

13-46

9-42

10

8-26

8-36

11-46

11

6-87

7-18

11-39

12

4-56

That is, during the first period, when 494 grammes of nitrogen
were ingested by each individual, the nitrogen of the faeces was
found to vary from 445 to 12-10 grammes. In the second period,
with an intake of 66-7 grammes of nitrogen, the faecal nitrogen
varied from 7-01 to 16-15 grammes, and in the third period from
7-79 to 11-46 grammes, when the intake was 43-1 grammes of
nitrogen.

These are certainly most surprising results, and entirely at
variance with what would be expected to be the case with healthy
men living on the same dietary. No such variations are usually
met with under normal conditions, and, unless some fallacy has
crept in during the isolation of the faeces for the stated periods,
it is impossible to understand how such results were obtained.
Benedict offers the explanation that the variations in digesti-
bility of the same diet exhibited by the several individuals may
possibly be due to the abnormally low protein intake having
resulted in some disturbance of the alimentary tract, thus affect-
ing its power of absorbing protein or the products of its tryptic
digestion. Such a disturbance has been observed in animal
experiments when the protein of the diet had been allowed to
fall to a low level.

The figures shown above are of very great interest, and merit
closer examination. From them the following variations in the
absorption of protein by the different individuals on the same
diet are obtained for the three periods :

126 THE PROTEIN ELEMENT IN NUTRITION

First Period. Second Period.

Third Period.

Nitrogen intake
Nitrogen absorption :

49-4 grms.

66-7 grms.

43-1 grms.

Highest

91-0 per cent.

89-5 per cent.

82-0 per cent.

Lowest

75-5

75-8

73-4 „

Average

82-9

82-5

77-4

That is, extreme differences of 15-5, 13-7, and 8-6 per cent, in
the absorption of protein are shown by the several subjects experi-
mented with on the same diet during the three periods of nitrogen
balance. That such large variations could be met with in normal
healthy people is scarcely credible. Benedict quotes the results
of forty-eight digestion experiments in which the same food was
administered to thirty different individuals : Of 40 grammes of
nitrogen ingested during a three-day experiment, 4-7 grammes
were recovered in the faeces, whilst in the large majority of the
experiments the variation was but 2 or 3 decigrammes on either
side of the normal. It has now been well recognized that the
percentage composition of the faeces under all diets is so uniform
that some speak of foods as large or small faeces-producers, rather
than as being capable of incomplete or complete absorption. In
our work* on the dietaries of Bengal gaols, the percentages of
nitrogen in the faeces was found to be fairly uniform under dif-
ferent conditions, whilst the total loss of nitrogen varied largely
with the total weight of the stools passed. Also, over a very large
number of observations made on prisoners f in the United Pro-
vinces, the percentage of nitrogen in the faeces was found to vary
within very narrow limits, whatever the composition of the diet
happened to be, whilst the total amount of faecal matter and the
total loss of nitrogen to the body varied directly with the weight
of the dietary, so long as it was composed of the same food
materials.

Some of the results obtained with batches of prisoners may be
quoted to show how very little variation in the absorption of
protein is met with in different individuals when on identical
dietaries (see table, p. 127).

Although these diets are seemingly identical, the fact that the
foodstuffs forming them differed considerably in chemical com-
position in the several gaols introduces extraneous factors in a

* Scientific Memoirs, Government of India, No. 37.
t Ibid., No. 48, pp. 177-185.

CONCERNING LOW PROTEIN DIETARIES

127

comparison of the figures for the different gaols. By taking the
batches on the same diet in the individual gaols, we get strictly
comparable results, and it will be evident how very similar the
amounts of protein lost in the faeces are by different individuals
when under the same dietetic conditions. Many similar results
might be quoted to corroborate the finding of other experimenters,
and to show that practically identical quantities of protein are
absorbed by different individuals from the same diet, even when
dealing with the highly vegetable dietaries of the tropics.

Gaol.

Diet.

Nitrogen of Faeces.

Agra Gaol

( Wheat, 1
\ dal, vege- -
{ tables J

J5-96 grms.
\5-60 „

Benares Gaol

,,

/5-46
\5-53

Naini Gaol

„

/5-05
\5-00

Lucknow Gaol

»

/5-14
\5-02

Another important point made evident from a scrutiny of
Chittenden's figures is that the highest and lowest degree of
protein absorption is not shown by the same individuals in the
different periods. Thus, for example, take the case of No. 9 :
this man during the first period, with an intake of 49-06 grammes
of nitrogen, loses only 445 grammes in the faeces ; in the second
period, with an intake of 66-48 grammes of nitrogen, he loses 13-46
grammes in the faeces ; whilst in the third period, with an intake
of 42-45 grammes of nitrogen (considerably less than during the
first period), he loses 9-42 grammes in the faeces ; i.e., contrasted
with the first period, this man, with 6-6 grammes of nitrogen less
in his diet, actually loses over twice as much of its nitrogen in
the faeces. This means a protein absorption during the first
period of 91 per cent., and during the third barely 78 per cent.
Similarly, reference to the figures for Nos. 1, 4, 7, 9, 10, and 11
will show that there was a greater loss of nitrogen in the faeces
during the third period, with an intake of 43 grammes, than
during the first period with 49 grammes.

Comparison of the results given for the first and second periods,
and for the second and third periods, show very great irregu-
larities also. Thus, as a last example, we may take the figures
for No. 2 : with an intake of 49 grammes of nitrogen, he loses

128 THE PROTEIN ELEMENT IN NUTRITION

10-24 grammes in the faeces ; with an intake of 66 grammes, he
loses 7 grammes in the faeces ; and with an intake of 43 grammes
of nitrogen, he loses 9-38 grammes in the fasces. Kesults such as
these defy explanation, except on the assumption that they are
not the records of a normally working organism, or that, owing to
the difficulty in obtaining accurate collection of the fasces, except
when the subjects are under constant supervision, the faecal
nitrogen figures do not represent the total loss of nitrogen in some,
at least, of the recorded observations.

Taking into consideration the amount of vegetable material
in the composition of the dietaries during the three periods, it
would appear very probable that the higher figures given for the
loss of nitrogen in the faeces are more likely to be correct than
the smaller quantities. It is for this reason that it appears to us
probable that the total quantity of faeces passed during the periods
by some of the subjects was not collected in full amount. It
may be, on the other hand, as Benedict indicates, that the
higher figures given for the faecal nitrogen are abnormal, owing to
diarrhoea, or a low degree of protein absorption set up by some
disturbance in the digestive powers of the alimentary tract, and
which is the result of existence on a low level of protein meta-
bolism. Whatever the true interpretation of Chittenden's
figures may be, the fact remains that they are most irregular, and
in the present state of our knowledge cannot be accepted as
evidence of the merits of a low protein form of dietary. The
fact that only a very small proportion of the men showed a posi-
tive nitrogen balance during the first and third periods would
make it evident that the metabolism of 50 grammes of protein
per day was not sufficient for the needs of the body, even with
an average fuel value of 2,830 calories.

An examination of the results of the nitrogen eliminated in the
urine gives equally discordant results. The figures are given
in the table on p. 129.

Here, again, wide variations are recorded in the urinary
nitrogen of the different individuals on the same diet : in the
first period the limits are 40-12 grammes and 58-07 grammes ; in
the second period they are 42-37 and 56-60 grammes ; whilst in
the third period quantities of 28-89 grammes and 38-32 grammes
are found. On the whole, however, the figures are more uniform
than those given for the faeces, and it would therefore appear
probable that the subject of the experiment took more care in

CONCERNING LOW PROTEIN DIETARIES 129

the saving and collection of the urine than in the case of the
faeces.

Subjects.

First Period. Second Period.

Third Period.

Intake of nitrogen

49-40 grms. 66-70 grms.
45-13 50-74

43-10 grms.
35-21

2

44-54

55-32

33-19

3

42-66

42-37

*28-89

4

44-70

55-46

32-55

5

48-07

50-11

31-27

6

48-31

49-04

38-32

7

47-33

f55-10

36-81

8

40-12

49-90

32-52

9

58-64

56-60

37-15

10

45-07

49-08

35-41

11

46-98

|44-53

32-49

That such wide variations should occur in the elimination of
nitrogen in the urine with different individuals living on the
same diet shows how little reliance can be placed on the urinary
nitrogen as a measure of the total nitrogenous metabolism.
With single subjects over short periods it is a most unreliable
method, even when a correction is added for the nitrogen meta-
bolized, but which does not appear in the urine. With batches of
men over relatively long periods, the average quantity of nitrogen
excreted in the urine may be relied on to some extent, when all
sources of fallacy are guarded against and provided for.

A summary of the results obtained by Chittenden with his
eleven subjects shows —

Subjects.

First Period.

Second Period.

Third Period.

verage N. intake per man
,, (urine) ,,
(faces) ,,

8-23 grms.
7-75 „
1-41 „

9-53 grms.
7-25 „
1-66 ,,

8-62 grms.
6-79 „
1-95 „

That is, there is actually a lower amount of nitrogen excreted
in the urine during the second period, when the nitrogen intake
was 9-53 grammes, than during the first period, when it was only
8-23 grammes ; further, the quantity of nitrogen lost in the
faeces was higher in the third period than in the second period,
although the nitrogen intake was considerably less.

We may conclude this examination of Chittenden's results by

* Corrected for five days. f Corrected for seven days.

9

130 THE PROTEIN ELEMENT IN NUTRITION

pointing out that on an average during the second period, when
the men showed a positive nitrogen balance, the urinary nitrogen
points to a protein absorption of 76 per cent., whilst the true
amount is really 82-5 per cent. The absorption of protein for
the subjects individually, on the other hand, based, according to
Chittenden's method, on the urinary nitrogen, shows much greater
variations : thus, No. 3 would seemingly show an absorption of
less than 64 per cent., the real amount being 75-3 per cent.,
according to the figures given for the total intake and the loss
of nitrogen in the faeces.

On the whole, while the figures recorded by Chittenden for
the balance period and those given for the elimination of nitrogen
in the urine during the several months of observation are open
to a considerable amount of criticism, the fact remains that these
men existed for months, if not on the low amount of nitrogen
per kilo of body weight that Chittenden found, at least on dietaries
that would appear to have contained very much less protein than
that provided in Voit's standard.* It must be accepted also
that during the period of five months the men showed no signs
of diminished strength or loss of bodily vigour.

The studies carried out with eight athletes demonstrate that
this class can very materially reduce the quantity of protein in
their diet, and, at the same time, gain enormously in strength,
and win in intercollegiate and other athletic contests. As these
men were in training before the change of diet took place, the
evidence afforded by their improvement in strength and physical
condition is of greater importance on the merits of a low protein
dietary than the increase in physical powers recorded in the
case of the soldiers.

It would appear from the opinions expressed by those in charge
of the training of these men that the good results obtained are
entirely to be ascribed to the lowered protein intake, whilst any
ill-effects can always be explained away as due to some cause
other than diet. Thus the winning of two championships is
specially suggested as being due to the restricted diet. Another
man won points for the first time ; others showed no falling off,
or were actually believed to have improved their position as
athletes. It is reported that all lost in weight, some very con-
siderably ; but that is made light of, and even regarded as a con-
dition devotedly to be wished. Considering that all these men

* For more recent information on this point, see note on p. 148.

CONCERNING LOW PROTEIN DIETARIES 131

were in hard training before the change of diet occurred, it is
open to doubt whether the loss of weight is to be regarded as of
little consequence in estimating the ultimate effects of a low
protein dietary. This is the very condition most evident in the
races of India, whose dietary for generations and centuries has
been deficient in absorbable protein ; the body weight is very low,
in spite of the diet containing considerable amounts of carbon-
aceous matter and being of great caloric value. The great
deficiency is met with in the muscular and protoplasmic tissues ;
nothing could be more remarkable than the miserable condition
of the musculature of those races whose dietary permits of a
protein metabolism complying with the standard laid down by
Chittenden as sufficient to meet the nitrogenous requirements of
the body. We believe — and the facts as met with on a large
scale in India warrant our belief — that, while it may be possible
for the average man or athlete to carry on for a time without any
very striking ill-effects on a low protein dietary, sooner or later
a breakdown will come, for which, doubtless, there may be the
most plausible non-dietetic explanations to offer, but which, in
truth, is the outcome of existence on a protein intake insufficient
to maintain the body in a high state of efficiency.

The conclusions Chittenden draws from the work done on these
eight athletes — and, indeed, the same applies to his soldier group
also — would be more convincing if the results had been con-
trolled, or even if there had been comparative tests with a similar
set of athletes on a liberal protein dietary. There must be records
of similar tests made in the progress of athletic training during
previous years, and it seems a pity, if such exist, that they have
not been made use of as a standard of comparison.

There is no doubt, however, that the reports on these men,
while on the restricted diet, show marked increase in strength
and skill in carrying out the tests. Considering the great interest
taken in intercollegiate contests, it is all the more remarkable,
if such marked benefit followed so rapidly on this dietetic altera-
tion, that similar changes have not been insisted on by trainers
and willingly accepted by athletes, not only at Yale, but all over
the world. Nothing of the kind has occurred. It is generally
believed that even the men, who are reported to have benefited
so greatly from the new ideas on the protein requirements,
returned at once to their former diet as soon as the experiment
was discontinued.

We may conclude the examination of Chittenden's three classes

132 THE PROTEIN ELEMENT IN NUTRITION

of experiment by summing up the objections put forward to them,
and to any general adoption of dietaries containing the low level
of protein he advocates :

1. The method of basing the protein requirements of the body
on the average amount of nitrogen eliminated in the urine gives
too low a result for the protein metabolism per kilo of body
weight.

2. The very great variations recorded for the digestibility and
absorption of protein from identical diets for the individual
members of his second group — men of the hospital corps — can
either be explained on the basis of malnutrition of the intestinal
epithelium, the result of a diet poor in protein, or by failure of
the men to collect all the faeces passed each day, so that the
total amount included in the analyses was too low. For several
reasons we believe the latter to be the more likely explanation.
If this should be the explanation, it must throw a certain amount
of doubt on the collection of the daily urine for the five months
during which this experiment was carried out. Any loss of urine
would mean a seemingly lower level of nitrogenous metabolism
than was actually the case. It is well known how difficult it is
to save all the excretions, except where the most rigid precautions
are taken. In the work in India we found it absolutely necessary
to confine prisoners under observation to solitary cells, in order
to insure the complete collection of the urine and fseces. This
criticism would not apply to Chittenden's first and third groups
of subjects, who were educated men, and who would fully under-
stand the importance of saving the excreta in full.

3. Whilst one feels bound to accept the figures stated for the
daily intake of nitrogen in the dietaries published throughout
Chittenden's book, at the same time one cannot help feeling that
they would have been much more satisfactory if the nitrogen of
those dietaries had been computed from analyses of the dry
food materials used, before being cooked, instead of being esti-
mated by means of factors for the percentage of nitrogen in
cooked food. The percentage of moisture in any cooked food
may vary very considerably from day to day ; this would be
specially marked with the more or less vegetarian types of diet
Chittenden was compelled to have recourse to in order to keep
down the protein content.

Apart from these technical objections which could be easily
overcome, there has been considerable mass of criticism levelled

CONCERNING LOW PROTEIN DIETARIES 133

at Chittenden's results, and the more remote effects of dietaries
low in protein. Hutchison* summarizes some of these, and
Crichton-Brownef discusses many others in detail :

1. While a low standard of protein intake may be adopted
with apparent impunity for considerable periods, it does not
follow that it can safely be pursued indefinitely. Excess of
protein is regarded as a margin of safety in increasing the general
tone of the system and the resistance to disease. Just as chronic
excesses in diet are slow in exacting their penalties, so a sub-
liminal diet may also be tardy in manifesting its untoward effects.

It is generally recognized that abrupt changes in the daily
food are very liable to produce gastro-intestinal trouble and
failure in health. It is quite possible that radical changes, even
when gradually introduced, may have ill-effects of an insidious
nature long before there is any obvious breakdown in health.

2. Existence at the lower limits of protein metabolism un-
doubtedly results in a wasting of the nitrogenous tissues and
fluids of the body during every special call or demand for increased
effort. This disintegrated tissue may take weeks to replace, and
thus convalescence from illness may be prolonged and recovery
rendered incomplete.

3. The effects of a diminished protein intake on the race is of
far greater importance than on the individual. The experiences
gained in India are specially interesting from this point of view,
and will be fully discussed presently. Suffice it at present to
say, that those people whose dietary affords a low level of protein
metabolism are, so far as our knowledge goes, of poor physique,
wanting in stamina, and lacking in the manly quantities that are
essential in commanding and maintaining the respect of the more
virile races.

4. Chittenden's claim, that the elimination of crystalline
nitrogenous bodies through the kidneys places upon these organs
an unnecessary burden, which is liable to endanger their integrity,
and possibly result in serious injury, in so far as it applies to the
ordinary accepted standard, cannot be substantiated, and is
opposed to universal experience.

Many other points might be raised, some of which we shall
discuss in detail later. One very important subject is the bearing
of a low protein dietary on the susceptibility to disease. We have

* Hutchison, " Food and the Principles of Dietetics," p. 24.
t Sir J. Crichton-Browne, " Parsimony in Nutrition," 1909

134 THE PROTEIN ELEMENT IN NUTRITION

already referred to the marvellous results that followed an in-
crease in protein of the ration of the Japanese Navy. The
importance of a liberal dietary in the treatment of certain patho-
logical conditions is well recognized by the medical profession.
The lymphocytosis that accompanies digestion has been shown
to be much increased by a diet of raw meat, and the modern
methods of combating tuberculosis make use of a regimen in
which protein is in liberal quantities as the best means of arresting
the disease. The marked success that has attended the Weir-
Mitchell treatment, one element of which is high protein feeding,
is acknowledged on all sides. According to Chittenden's ideas,
this heavy protein intake, combined with rest, should set up all
manner of ailments. The results are exactly the opposite : the
nutrition of the patient is restored and health returns. In India,
the home of epidemic diseases, famines or years of scarcity never
fail to be accompanied by outbreaks of infections which pick out
with unfailing regularity those who have become enfeebled from
want of proper food. Examples of the great importance of a
high level of nutrition in decreasing the susceptibility to infection
could easily be largely multiplied, but enough has been said at
present to give us pause before accepting the conclusions arrived
at by Chittenden from experiments largely laboratory in nature,
and carried out under relatively artificial conditions.

It has been estimated that over 30 per cent, of the population
of the large towns in England and other countries are in a condi-
tion of under-nourishment from chronic under-feeding ; the
consequences of this is not " increased vigour, improved health,
and exhilaration of spirits, but weakness, misery, and degenera-
tion." The lethargic appearance of the protein-starved, rice-
eating populace of parts of the tropics is in marked contrast to
the alert and energetic demeanour of those who, living under
absolutely identical conditions as regards climate and customs,
are able to afford a dietary in which a sufficient amount of absorb-
able protein is present.

In connection with this thought, the following excerpt from
a work by Nietzsche may be quoted : " When a profound dislike
for existence gets the upper hand, the after-effects of a great
error in diet of which a people has been long guilty comes
to light. The spread of Buddhism (not its origin) is thus to a
considerable extent dependent on the excessive and almost
exclusive rice fare of the Indians, and on the universal enerva-

CONCERNING LOW PROTEIN DIETARIES 135

tion that results therefrom. . . . The increased prevalence of
rice-eating impels to the use of opium and narcotics. ... It
also impels, however, in its more subtle after-effects, to modes of
thought and feeling which operate narcotically."

Dr. I. M. Mullick,* in a study of the medical aspect of student
life in Calcutta, states that 50 per cent, are melancholic, pessi-
mistic, never enjoy life properly, this condition arising both from
actual want as well as from imaginary evils. In dilating on their
ill-developed, weak, and defective physique, he ascribes the
important cause to diet and an insufficient amount of easily
assimilable protein. As a result of protein starvation, the
muscles are enfeebled and the body does not attain its full develop-
ment and growth ; these effects on the race are most lasting and
dangerous. Hence the preponderance of so many infectious
diseases in the land, which are largely predisposed to by the low
resisting power of the system.

We may now refer to some other observations and investi-
gations bearing on the merits or demerits of the low protein
standard advocated by Chittenden. The very interesting and
instructive knowledge, gained from experiences in the local and
convict prisons of England, with the dietaries in force before the
introduction of the present scales, is of special importance :

No. 1 diet provided —

Protein . . 57 grms. "I

Carbohydrates .. 341 ,, V Caloric value, 1,464 calories.

Fat .. .. 19 „ J

— i.e., practically identical with Chittenden's protein standard.

No. 2 diet provided —

Protein . . . . 70 grms. }

Carbohydrates . . 385 ,, VCaloric value, 1,684 calories.

Fat .. .. 21 „ J

— i.e., considerably above Chittenden's standard in protein.

Convict diet for light labour provided —
Protein . . . . 133 grms. |

Carbohydrates . . 478 ,, \ Caloric value, 2,398 calories.
Fat .. .. 44 „ J

— i.e., greatly in excess of the amount of protein Chittenden
would consider amply sufficient.

These dietaries had been in force for twenty years, and were
regarded as physiologically correct and amply sufficient. How-
ever, when the subject came before Parliament, a terrible indict-

* Dr. Mullick, Calcutta Medical Journal, April, 1909.

136 THE PBOTEIN ELEMENT IN NUTKITION

ment was brought against them by members who had had prac-
tical experience of their ill- effects. A committee was appointed
to examine and report on their adequacy, with the result that
they were condemned, and new scales — considerably more liberal
— were introduced.

It was clearly proved that Diets 1 and 2 were absolutely
insufficient to satisfy the pangs of hunger, and were injurious to
health, as indicated by a loss of weight. Many suffered from
gastro-intestinal disturbances, thus conforming with the experi-
ences of Munk and Rosenheim when feeding dogs on a low protein
dietary. In this connection it may be pointed out that intestinal
disorders are exceedingly prevalent in India ; but they are very
much more common amongst the rice-eating, protein-starved
populace than amongst those whose dietary contains some of the
superior cereals.

Evidence was produced to show that prisoners would go to
almost any extreme to satisfy the pangs of hunger. Men would
gather and eat snails, eat the putrid marrow of bones, pick up
fragments of candles, purposely made offensive so as not to be
eaten, wipe them with their clothes, and eat them. These were
the immediate effects of diets Chittenden believes amply suffi-
cient ; the remote consequences were probably still more glaring
and far-reaching. The number who left the prisons perma-
nently broken in health as the results of dietetic privation and
impaired nutrition will never come to light, but we are justified
in assuming, in the light of the recognized influence of privation
in predisposing to tuberculosis, that many on this account fell
victims to the tubercle bacillus.

One of the most valuable studies of prison dietaries is that
made by Dr. J. C. Dunlop for the Prison Commission of Scotland.
His standards are based on careful investigations carried out
on scientific lines, and upon actual experience have been found
satisfactory. Starting with the amount of food necessary to
nourish the body, the quantity is modified according to the
different conditions of the individuals to be fed. The more
important dietaries are given in the table on p. 137.

Dr. Dunlop found that prisoners, when reduced below 3,500
calories of food energy per day, 82 per cent, of those of average
size lost weight.

In France the prison dietary provides —

Protein 94 grms. "j

Carbohydrates 374 „ V 2,074 calories,

Fat . . 22

CONCERNING LOW PEOTEIN DIETARIES

137

or over one-third more protein than the Chittenden standard ;
yet Dr. Gautier, the greatest French authority on dietetics,
states that it is too poor in protein, even for a man who does
not work. He lays it down that a man on hard labour should
be provided with 135 grammes of protein and from 500 to 700
grammes of carbonaceous material — more than double the Chit-
tenden standard.

DUNLOP'S STANDARDS.

Different Classes of Prisoners.

Protein.

Fat.

Carbo-
hydrates.

Energy
Value.

Grms.

Grms.

Grms.

Calories.

Ordinary male prisoners

120

38

550

3,100

female

96

30

440

2,480

,, ,, ,, (nursing)

105

54

482

2,910

Male prisoners unemployed

90

30

440

2,400

Female ,, ,,

72

23

330

1,860

Male convicts, hard labour

150

65

550

3,500

light „

120

50

550

3,200

Female convicts

100

41

440

2,600

Punishment diet . .

90

30

440

2,400

,, ,, (subsistence)

64

21

341

1,850

It may be concluded, therefore, from the knowledge gained
from a study of prison dietaries, that the results do not bear out
Chittenden' s contentions.

Other points bearing on this subject have been admirably
summarized by Spriggs in his article on the results of experi-
mental work on diet.* He quotes Darwin's remarks on his visit
to the Chilian copper mines. The ore had to be carried up a
450-feet shaft in loads of 200 pounds. The men were pale, and
some of them with but little muscular development. They were
fed on beans and bread ; the men preferred bread, which was a
luxury ; but the masters, finding they could not work so hard
upon this, were accustomed to treat them like horses, and make
them eat the beans. In beans 20 per cent, of the energy is in the
form of protein, whereas in bread only about 12 per cent, is
present as such.

Livingstone records that the grain-eating tribes of Central
Africa could not endure fatigue so well as the beef-eaters, who
scorned the idea of ever being tired.

Dr. Zieman, from a careful study of the hygienic conditions
of tropical Africa, states that one of the most influential of the

* Spriggs, " A System of Diet and Dietetics." Sutherland, 1908.

138 THE PROTEIN ELEMENT IN NUTRITION

causes which tend to diminish the number and impoverish the
physique of the coloured races is not over- but under-feeding.

On the other hand, Irving Fisher claims that a decrease in the
protein element of the diet is favourable to endurance. He
carried out a series of feeding experiments on nine healthy
students, lasting for five months, with endurance tests at the
beginning, middle, and end of the period. During this period
the total calories of the daily ration had fallen 25 per cent., the
protein 40 per cent., and the fresh food 80 per cent. Six simple
gymnastic tests were employed, such as raising the body on the
toes, holding the arms horizontally, raising and lowering the
dumb-bell.

The endurance was found to be much greater at the end than
at the beginning of the experiment. It appears to us these
tests are not of the slightest value, unless the nine students were
under constant supervision, and it could be definitely stated
that they did not practise the required tests in the intervals.
These observations, again, were carried out without controls,
and it is more than probable that the results recorded are easily
explained as due to practice by the students in order to make
the experiment a success.

On the other hand, the students showed loss of strength in the
grip and loss of weight. These ill-effects are attributed to over-
study or other causes, but the increase in endurance was, of
course, entirely due to the low protein dietary. Spriggs remarks
that these considerations do not inspire confidence in the diet.

Fortunately, in the interests of truth, we are able to place on
record some evidence of very recent date, which appears to us
to be of considerable value in appraising the effects of a low
protein dietary. It has already been shown that the average
Indian student in Calcutta lives on a protein metabolism closely
approximating the Chittenden standard, whilst Anglo-Indian
and Eurasian students receive dietaries more nearly approaching
Voit's standard. We shall have more to say on the effects of
this difference later, but at present a brief account of the com-
parative tests afforded by the intercollegiate athletic sports in
Calcutta will be given.

Twelve colleges entered representative teams to compete in
the different events. The very great majority of the students
attending these colleges are Indian, the Anglo-Indian and
Eurasian probably not exceeding 2 per cent, of the total number.

CONCERNING LOW PROTEIN DIETARIES 139

Despite the small community to select from, the Anglo -Indian
and Eurasian were largely chosen by the athletic clubs to repre-
sent their colleges. The results of the tests, which included the
usual events — 100 yards, hurdles, 220 yards, 440 yards,
half, and mile races, broad and high jump, tug-of-war, etc. — are
very striking. The Anglo-Indians and Eurasians were first and
second in nine out of twelve events : the prizes for the com-
petitors who won most events, awarded on points, were both
secured by Anglo-Indian and Eurasian ; the challenge shield
offered for the college whose representatives scored the greatest
number of points was won by the college which was almost
entirely represented by Anglo-Indians and Eurasians — in fact,
the Indian students were outclassed in almost every test, whether
of strength or skill.

These results are even more remarkable than they appear at
first sight. The students of Anglo-Indian and Eurasian extrac-
tion enter college much younger than the Indian students, and
are not fully developed until their last two years in residence.
The Indian students have large numbers to choose from, and
great interest is taken in sports of all kinds, each of the colleges
having flourishing athletic, cricket, football, and other clubs.
Yet, despite their comparatively insignificant numbers, and their
relatively immature age, these Anglo - Indian and Eurasian
students were markedly superior to their Indian fellow- students
in tests that were strictly comparable. It is not to be under-
stood, however, that all Anglo-Indians and Eurasians develop
into men superior in physique to the Indians ; the properly fed
do, but the cities, and particularly the hospitals, are full of
miserable specimens who, owing to their poverty-stricken con-
dition, are unable to afford other than the cheapest food materials,
and who live on dietaries no better than, if as good as, the poorer
classes of Indians.

Other points of evidence bearing on the question have been
put forward. Thus Benedict states, from the results of numerous
dietary studies made with different classes of people living under
different conditions, that it has been observed that with com-
munities a generally low condition of mental and physical
efficiency, thrift, and commercial success is coincident with a
low proportion of protein in the diet. He cites the negro and
poor white of the South, and the Italian labourer of Southern
Italy, all of whom partake of diets relatively low in protein,

140 THE PROTEIN ELEMENT IN NUTRITION

and states that their sociological condition and commercial
enterprise are on a par with their diet. Yet, when these people
are fed on a higher protein plane, their productive power increases
markedly.

All the successful races have habitually consumed protein far
in excess of the amount Chittenden believes sufficient, whereas
those who have adhered to a low protein standard have not pro-
gressed physically, mentally, or morally. The poorer races of
India and the tropics illustrate this truth, and show that the
conquering races and nations are all high protein feeders.
Chittenden would have us believe that they are high protein
feeders because they are conquerors, but the facts do not bear-
out his contention.

We shall now consider briefly the knowledge gained on this
subject from experimental work done on animals, reserving for
the following chapters the more recent observations and investi-
gations made on some of the different tribes and races of India.

EXPERIMENTS ON ANIMALS.

Numerous studies have been made on the effects of decreasing
the protein element in the food of different animals.

Munk, Rosenheim, Hagemann, and Jagerroos, have made
investigations bearing on the question of the reduction of the
protein in the diet of dogs. Rosenheim and Munk obtained bad
results when the protein element was decreased to 2 grammes of
protein per kilo of body weight ; the animals suffered from
digestive troubles, such as vomiting and loss of appetite. They
showed very defective absorption of food, and after a few months
died in an apathetic condition.

Jagerroos, taking special precautions, was able to keep two
bitches alive for six and a half months on an intake of less than
2 grammes of protein per kilo of body weight. Both these dogs
died rapidly, not, as Jagerroos states, from the results of protein
starvation and inanition, but from an acute infection contracted
after the premature delivery of one of them : in all probability
due to a lowered resistance to infection from the ill-effects of
poor feeding.

Chittenden, in a report on experiments completed on six dogs,
traverses the results reported by previous investigators, and
states that they were not due to the effects of low protein, or
to a diminished consumption of non-nitrogenous food, but are

CONCERNING LOW PROTEIN DIETARIES 141

to be ascribed mainly to non-hygienic conditions, or to a lack
of care and physiological good sense in the prescription of a
narrow dietary not suited to the habits and needs of this class of
animal.

Chittenden's experiments on dogs were carried out under the
most favourable circumstances to insure the successful issue of
the investigation. The animals were nursed and tended in the
most painstaking manner, and every source of danger was
guarded against. It must be acknowledged that he has accom-
plished what no previous experimenter had been able to do —
viz., maintain dogs in fair health and keep them alive for varying
periods of time over six months on dietaries providing less than
2 grammes of protein and 80 calories of fuel value per kilo of
body weight.

As an example of the thorough and whole-hearted methods
Chittenden has made use of throughout all his researches on
nutrition, nothing he has done shows more clearly his infinite
capacity for taking pains than the prolonged experiments
devised and carried out with such scrupulous care on these dogs.
However, even his methods and results in this experiment have
been unfavourably criticized. It has been pointed out * :

1. He proves too much, for in several instances, as the nitrogen
and fuel value of the diet per kilo of body weight became re-
duced during the course of the experiment, his dogs actually
increased in weight. No. 5 dog increased from 15-5 to 20 kilos
on reduction of the nitrogen from 0-54 to 0-26 gramme, and the
fuel value from 87 to 65 calories per kilo of body weight. It
almost appears as if nitrogen in the diet were entirely super-
fluous.

2. No notice is taken of the build and shape of the animal,
although the body surface, and consequently the amount of heat
lost by radiation, must have varied enormously.

3. The kind of dog is not specified, which is a point of great
importance, as different kinds of dogs are habituated to different
kinds of diet. Some dogs get practically no meat ; others, like
the coursing greyhound, are trained on the best beef and mutton.

4. They led a placid and cloistered existence. For ten days
in each month they lived in the metabolism cage, and for the
remainder of the time practically in kennels.

5. Not until a pack of foxhounds have got satisfactorily
through a winter's work on Chittenden's reduced diet can his

* Sir J. Crichton-Browne, " Parsimony in Nutrition."

142 THE PROTEIN ELEMENT IN NUTRITION

experiments be accepted as anything more than a curious
physiological feat.

6. The experiences of zoological gardens, farmers, breeders of
cattle, horses, and domestic pets, are all quoted against Chitten-
den's conclusions. In fact, he would appear to stand alone
against the world in his stringent ideas on protein economy.

On reading carefully through the accounts of these experiments,
two other points appear to be worthy of attention. One is the
exceedingly small amount of nitrogen lost to the body in the
fseces, being often less than that given for the nitrogen " lost
through hair." Thus, for the total of the eleven periods re-
cording the nitrogen balances of subject No. 5, the nitrogen lost
in the faeces amounts to 5-93 grammes, whilst that lost " through
hair " is 5-44 grammes. Another point is that the protein
absorption from the dietaries made use of does seem to have
fallen as the experiment proceeded.

Taking subject No. 5 again — the only one concerning which
we have any details — we find the following results :

DIET I.

Meat . . . . 172 grms. ]

Cracker dust . . 124 ,, V Absorption of protein, 91 per cent.

Lard .. .. 72 „ J

DIET II.

Meat . . . . 70 grms. \

Cracker dust . . 124 ,, V Absorption of protein, 93 per cent.

Lard .. .. 72 „ J

— i.e., although the highly absorbable protein of meat was
reduced from 172 to 70 grammes, the protein absorption from
the diet increased by 2 per cent.

DIET IV.

Meat . . . . 69 grms. ]

Bread . . . . 166 ,, !- Absorption of protein, 91 per cent.

Lard .. .. 80 ,, J

DIET VI.

Meat . . . . 70 grms. }

Cracker dust .. 158 ,, V Absorption of protein, 86 per cent.

Lard .. .. 60 „ J

Contrasting the result shown by Diet VI. with the protein
absorption from Diet II., a fall of 7 per cent, would not be
expected, unless the intestinal power of absorption had become
less efficient as the dieting proceeded. Chittenden, while
admitting that the utilization of nitrogen becomes less complete
in the later dietaries, attempts to explain it away as being due

CONCERNING LOW PROTEIN DIETARIES 143

to a decrease in the quantity of readily digestible meat and an
increase in the vegetable material of these diets. As will be
evident from the diets selected above, this explanation will not
cover the facts. Diets II., IV., and VI. are practically identical
in their absorbability, yet the dog shows considerable variations
in the quantity of protein he was able to utilize. It is therefore
not quite clear from these experiments that the absorptive func-
tion of the intestinal epithelium did not suffer to some extent
by the protein content of the dietaries remaining at so low a level
for many months. This would be in harmony with the con-
clusions arrived at by Munk and Rosenheim from a similar series
of experiments, and would militate against the view that a
material reduction of the protein in dietaries is to the welfare
of the body.

All these experiments on dogs are open to the criticism that
the dog is a carnivorous animal, and that the results are there-
fore not directly transferable to man. We shall now refer to
some experiments on animals that are more nearly allied in food
habits to man. The most important of these are the investi-
gations made into the effects of feeding swine on a low and on a
high protein dietary respectively.

The digestive organs of the pig are regarded as being closely
comparable to those of man, and the pig, being an omnivorous
animal, like man, is not open to the same objection as the dog
in estimating the merits or demerits of a low protein dietary.
Benedict, quoting from Shutt's valuable and interesting paper,*
states that extensive investigations on " soft " pork show con-
clusively that when hogs are fed on a low protein diet — i.e.,
Indian corn — the pork is of very inferior quality ; while if the
protein content of the diet is raised by the addition of skim milk,
legumes, or other nitrogenous materials, the quality of the pork
is very markedly improved.

Canadian pork butchers find also that the intestines of hogs
fed on low protein rations tear more easily when the carcass
is dressed — that is, the intestines are not so firm. This would
appear analogous to the condition described by Munk and
Rosenheim as occurring in the intestines of the dogs they in-
vestigated in their feeding experiments with dietaries deficient
in protein. A bad quality of pork is also produced when the
diet is excessively high in protein, so that swine are unusually
sensitive to marked alterations in the protein content of the diet.

* Shutt, Bulletin No. 38, Department of Agriculture, Ottawa, Canada.

144 THE PROTEIN ELEMENT IN NUTRITION

These Canadian observations have been corroborated by the
work of Skinner* in Indiana, who fed hogs on a low protein
dietary of Indian meal. This diet caused impairment of the
digestive capacity, which became more apparent the longer the
diet was continued. It resulted in " poor appetites, light bone,
deficient development in valuable portions of the carcass, and
a general state of unthrift, as shown by the hair, skin, and
hungry look of the animals." The addition of one-sixth of the
amount of the ration in materials rich in protein resulted in
normal growth and a healthy condition.

A similar series of experiments have been carried out by Pro-
fessor Haecker on herbivorous animals. Benedict, quoting
from unpublished results, remarks that herbivora being accus-
tomed to diets relatively low in protein, a further decrease
would be expected to be accompanied by less marked disturb-
ances, which might take a considerable time to develop, than
in the case of carnivora or omnivora.

Haecker' s investigations were carried out with the view of
determining, from an economical standpoint, to what extent
the amount of protein could be decreased with safety and
economy .

Two groups of cows of ten in each group were fed for a period
of three years, one group on a diet containing the normal pro-
portion of protein, the other on a much lower protein ration.
No ill-effects appear to have been noticeable for some time,
although the second group had lost somewhat in weight. During
the first part of the third winter both groups did well, but by
January the cows receiving the low protein dietary began to
fail. By March 13 it became absolutely necessary to increase
the proportion of protein, as the cows had become very thin in
flesh, and their coats dry and harsh — a well-recognized indication
of under-nutrition.

It is particularly worthy of attention that the effects of a
low protein dietary on the pigs and cows was very gradual, but,
nevertheless, led in time to a general deterioration of health.
The importance of this in appraising the merits of dietaries low
in protein for man cannot be over-estimated. It demonstrates
clearly that experiments with diets of low protein content, to
be conclusive, should last for years, as the beneficial effects of
previous high protein feeding may be persistent and prolonged.

* Skinner, Indiana Agriculture Experimental Station, Bulletin No. 108.

CONCERNING LOW PROTEIN DIETARIES 145

It may be concluded from the evidence so far adduced that a
considerable mass of experimental facts and deductions from
accurate observation have been accumulated, which, in their
general bearing, militate very strongly against the conclusion
that a marked reduction in the protein element of the average
diet is either necessary or desirable. We have summarized
some of the technical and more general objections that a critical
examination of Chittenden's investigations on his three groups
of subjects would make apparent. The object of our scrutiny
of Chittenden's work and of the different points brought forward
has been to determine whether the records demonstrate any
evidence of ill-effects due to dietetic changes. Several such
demerits have been pointed out, and others suggested.

When a survey is made of Chittenden's brilliant piece of work,
it must be admitted that he has made out a very strong case.
He has been the first to show that man can live and do a certain
amount of work on an intake of protein much below the ordinary
accepted standards without increasing — indeed, with a con-
siderable diminution of — the fuel value of the diet. While
accepting this finding, we have shown that there remains a
considerable degree of doubt whether his subjects did live during
the months of experimentation on the low protein dietaries
the urinary nitrogen would indicate.

As pointed out, serious sources of error may have resulted, in
the absence of supervision, from the failure of the different
individuals to collect and surrender the full amount of the daily
urine and to adhere strictly to the diet prescribed. Even during
the periods of balance, when the food partaken of was accurately
weighed and its nitrogen content estimated, the fact that this
nitrogen was computed from certain factors for the percentage of
protein of cooked foods leaves open a considerable loophole of
error. The great irregularity displayed by the individuals
of his second group in their utilization of the protein while
on absolutely identical diets does not tend to inspire con-
fidence in the accuracy with which the members of the
Hospital Corps collected the faeces ; or, if this view be doing
them an injustice, and the figures given are correct, then the
varying absorption of protein they indicate can only be explained
as an ill- effect of the abnormally low protein dietary — seriously
injuring the absorptive function of the intestinal epithelium.

These doubts are strengthened when the figures for the fuel

10

146 THE PKOTEIN ELEMENT IN NUTRITION

value of the diets are taken into consideration. Chittenden
would not only lower the protein standard, but would likewise
decrease materially the potential energy of diets. Whatever
may be the true physiological requirements of the body for
protein in maintaining it in a thorough condition of efficiency,
there can be no doubt concerning the recognized fact that the
total energy requirements must be met by the oxidation of the
food partaken of, unless the organized tissues or reserve materials
are to be drawn on. Benedict, from a series of brilliant experi-
ments, carried out by means of the respiration calorimeter, has
shown that a man of average size, weighing 66 kilos, and at rest
within the calorimeter, in twenty-four hours expends about
2,270 calories. The average individual under ordinary condi-
tions, but not at work, would require more ; whilst the same
individual engaged in labour will dissipate large amounts of
energy in proportion to the work done. Quantities up to 600
calories per hour have been recorded as the output of energy by
a professional bicycle rider.

It has been shown from these experiments that the total
energy estimated by Chittenden for some of the dietaries his
subjects lived on was considerably less than the quantity neces-
sary to meet the ordinary requirements of the body, and markedly
lower than that essential for the body at work. The case of
Mr. Fletcher, already briefly referred to, is most instructive
from this standpoint. Professor Chittenden concluded that
Mr. Fletcher was able to perform the work of a member of the
Yale University crew on an intake of 1,700 calories. Exact
observation on Mr. Fletcher for three days in the respiration
calorimeter, most of his time being spent reclining very quietly
on a cot, or sitting reading and occasionally writing on a type-
writer, showed the average output of energy to be 1,896 calories,
whereas the amount of energy actually derived from the food
averaged only 1,357 calories.

In view of these results when at rest, Benedict states that it
is safe to assume that Fletcher could not have taken the exercises
of the Yale University crew on an expenditure of less than
3,000 calories. If the estimate of 1,700 calories of intake be
correct, then he must have drawn on his tissues to an extent of
1,300 calories daily, or about one-third pound of body fat.
Yet Chittenden records that not only was he in a condition of
nitrogenous equilibrium, but that his body weight also remained
practically unchanged.

CONCERNING LOW PROTEIN DIETARIES 147

How are these contradictory results to be explained ? It has
been suggested that, while Fletcher oxidized his own tissues to
obtain the extra energy required, owing to the amount of carbo-
hydrates in his diet, retention of water took place, so that the
body weight remained the same. This may be the true ex-
planation, but it seems a strange coincidence that the weight
of water retained should exactly balance the loss to the body
through the disintegration and oxidation of its tissues. What
appears a far more rational explanation would be that, owing to
faulty methods, the caloric value of Fletcher's dietary during the
six days was estimated at too low a figure.

This explanation is borne out by a consideration of the ex-
perimental work on Chittenden's second group of subjects — the
members of the Hospital Corps. It will be readily recognized
that a retention of water maintaining the body weight might
act temporarily, but that it could not go on indefinitely.

What are the facts ?

Benedict and Carpenter* have shown, as a result of experiments
in the respiration calorimeter on fifty-five men, with an average
body weight of 64-5 kilos, awake and sitting quietly in a chair,
that the average heat production was 97 calories per hour.

Calories per Hour.

With seventeen men asleep, the heat production was . . 71
Man at rest, standing, the heat production was . . . . 114
Man at severe muscular exercise, the heat production was 653

Chittenden's soldier group led quite active lives, rising at
6.45 a.m., occupied with various duties all day, including two
hours' activity in a gymnasium in addition to regular drills,
walking, instruction in nursing duties, assisting in laboratory
work, etc.

According to Chittenden's figures, the average heat value of
the diet was —

Calories.
From October to the middle of January . . . . . . 2,078

From middle of January to early in March . . . . 2,500

From early in March to early in April 2,840

The average caloric value of the dietaries for the six months
of observation works out at a little over 2,300 daily. This
amount, according to accurate determinations based on exact
scientific experimental methods, would not be nearly sufficient to

* Benedict and Carpenter, " Metabolism and Energy Transformations of
Healthy Man during Rest," 1910.

148 THE PROTEIN ELEMENT IN NUTRITION

meet the demands for energy in the performance of the mildest
forms of muscular activity, and, therefore, would be much less
able to permit of the carrying out of the varied duties detailed
for these soldiers.

Examination of the records for the professional and athletic
groups would indicate that in these cases also the energy fur-
nished by the dietaries, if correct, was insufficient to meet the
different conditions that obtained.

The only conclusion to be drawn from these facts is that,
unless all the world is wrong again, as Chittenden believes it to
be with regard to the nitrogenous requirements of the body, in
holding that the law of the conservation of energy obtains in
the human organism, and that we must therefore fall back on
the discarded theory of vitalism, there must be some unexplained
source of fallacy in the figures given for the potential energy of
the dietaries on which the three groups existed.

We believe this fallacy can be explained on the assumption
that the factors made use of in calculating the energy of the
foodstuffs were too low, and that the diets during the periods
of nitrogen balance do not accurately represent the total food
consumption in the long intervening periods. As already stated,
we had arrived at a somewhat similar conclusion with regard
to the level of nitrogenous metabolism exhibited by the subjects
of the experiment.

Since this was written Loeser, in a paper* dealing with the
good effects of an increased standard of protein metabolism on
the stamina and general efficiency of miners in the Transvaal,
states that inquiries, made from the soldiers of Chittenden's
second group, elicited the important information that the men
admit to have had " square meals on the quiet " during the
whole period of the experiment. If this was really the case, it
would explain much that is otherwise inexplicable in Chittenden's
results, as discussed above, and would lessen considerably the
value of his conclusions as regards the protein needs of the body.

Against the conclusions arrived at by Chittenden, we have
cited a considerable number of facts and observations based on
the known effects and results that follow existence on dietaries
low in protein. We shall now turn to the evidence afforded
by the inhabitants of large tracts of India, and consider what
light the conditions that obtain throw on the merits or demerits
of dietaries poor in protein.

": Transvaal Med. Journ., 1912.

CHAPTEK VII
THE EFFECTS OF A LOW PROTEIN DIETARY IN THE TROPICS

EFFEMINACY OF THE INHABITANTS OF INDOSTAN.

" SOUTHWARD of Lahore we see throughout India a race of men
whose make, physiognomy, and muscular strength convey ideas
of an effeminacy which surprises when pursued through such
numbers of the species and when compared to the form of the
European who is making the observation. The muscular
strength of the Indian is still less than might be expected from
the appearance of the texture of his frame. Two English sawyers
have performed in one day the work of thirty-two Indians.
The stature of the Indian is various : the northern inhabitant
is as tall as the generality of our own nation ; more to the south,
the height diminishes rapidly, and on the coast of Coromandel
we meet with many whose stature would appear dwarfish, if
this idea were not taken off by the fineness and regularity of their
figures. Brought into the world with a facility unknown to the
labours of European women ; never shackled in their infancy
by ligatures ; sleeping on their backs without pillows, they are
in general very straight, and there are few deformed persons
amongst them.

" Labour produces not the same effects on the human frame
in Indostan as in other countries ; the common people of all sorts
are a diminutive race in comparison with those of higher castes
and better fortunes. Nature seems to have showered beauty on
the fairer sex throughout India with a more lavish hand than in
most countries. They are all, without exception, fit to be
married before thirteen, and wrinkled before thirty — flowers of
too short duration not to be delicate and too delicate to last
long.

" Montesquieu attributes much of the effects to climate, and

149

J50 THE PROTEIN ELEMENT IN NUTRITION

his critics impute to him to have attributed much more to this
effect than he really does. It is certain that there is no climate
in which we may not find the same effects produced in the human
species, as in climates entirely different in situation and in
every other circumstance. The Sybarites, whose territory was
not more than a day's journey from the country of the Horatii,
the Cincinnati, and the Scipios, were more effeminate than the
subjects of Sardanapalus.

" To produce this effect of effeminacy in Indostan nothing is
necessary but to give the man his daily food.

" The savage, by his chase and the perpetual war in which he
lives with the elements, is enabled to devour almost raw the
flesh of the animals he has killed. In more civilized nations the
ploughman from his labour is able to digest in its coarsest pre-
paration the wheat he has sown. Either of these foods would
destroy the common inhabitant of Indostan as he exists at
present ; his food is rice.

" To provide this grain, we see a man of no muscular strength
carrying a plough on his shoulders to the field. This slender
instrument of his agriculture, yoked to a pair of diminutive oxen,
is traced with scarce the impression of a furrow over the ground,
which is afterwards sown. A grain obtained with so little labour
has the property of being the most easily digestible of any pre-
paration used for food, and is therefore the only proper one for
such an effeminate race as I have described.

" There is wheat in India ; it is produced only in the sharper
regions, where rice will not so easily grow, and where the cultivator
acquires a firmer fibre. All the Mohammedans of northern ex-
traction prefer it to rice, as much as the Indian rejects a nourish-
ment which he cannot digest even in its finest preparation.

" The Indian, incapable as he is of hard labour, breathing in
the softest of climates, having so few real wants, and receiving
even the luxuries of other nations with little labour from the
fertility of their own soil, must become the most effeminate
inhabitant of the globe ; and this is the very point at which we
now see him, A.D. 1753."*

" Their legislators have even ordained different kinds of food
to the different tribes. The Brahmins touch nothing that has
life : their food is milk, vegetables, and fruit. The soldiers are
permitted to eat venison, mutton, and fish. The food of the

* R. Orme, " Historical Fragments of Hindustan," 1659.

LOW PROTEIN DIETARY IN THE TROPICS 151

labourers and mechanics varies according to their sects and
profession.

" The Gentoos of the lower provinces are a slight-made people.
Kice is their chief food. It seems to afford but poor nourishment,
for strong, robust men are seldom seen amongst them. Though
the people in general are healthy, they rarely attain to any great
age, which is in some measure made up to them by early
maturity."*

" Many of the Indians abstain from all kinds of animal food,
and the greatest part of them use rice as their common and
almost only sustenance. At the close of evening every man eats
an inconceivable quantity of rice, and may take after it some kind
of soporific drugs . . . the use of opium, which is to warm his
blood for action and animate his soul with heroism. It must fill the
mind of the European soldier at once with compassion and con-
tempt to see a heap of these poor creatures, solely animated by a
momentary intoxication, crowded into a breach, and both in their
garb and impotent fury resembling a mob of fanatic women."f

The above extracts give some idea of the opinions of the
earlier writers on the physique and the effects of diet on the
Indian. It must be remembered, however, that in the period
referred to the English had penetrated at no great distance from
the coast, and had no knowledge of the splendid fighting material
that was to be encountered later as English rule spread over
the land. In order to correct the impression that the above
picture applies to the people of India in general, one more extract
must be given :

" I am afraid that the belief that the people throughout India
live generally on rice is almost as prevalent in England as ever.
There could be no more complete delusion. Rice, in the greater
part of India, is a luxury of the comparatively rich. It is grown
where the climate is hot and damp, or where there are ample
means of irrigation. It is only in Lower Bengal, in parts of
Madras and Bombay, in Burma, and in districts where the
conditions of soil and climate are suitable to its abundant pro-
duction, that it forms the ordinary food of the people, or enters
to an important extent into the consumption of the poorer
classes. Out of the whole of the population of India it is probable
that not more than one-fourth live on rice.

* "Letters from Luke Scrafton, 1758." Bengal.

f "An Account of War in India v, the French on the Coast of Coromandel ,
from 1750 to 1760." Cambridge.

152 THE PROTEIN ELEMENT IN NUTRITION

" Except in the rice-growing countries, millets form the chief
foods of the population throughout almost the whole of India.
Pulses of various kinds are largely consumed. Little or no meat
is eaten by the poorer classes ; meat is, however, commonly eaten
by Mohammedans, and many of the Hindus who abstain from it
do so because it is an expensive luxury rather than from religious
scruples.

" The chief agricultural staples of Northern India are wheat
and barley. They occupy nearly 60 per cent, of the whole food-
producing area in the United Provinces. Wheat in the Punjab
is a still more important crop than in the United Provinces. It
is also extensively grown in parts of Central India, Northern
Deccan, and Bombay, and in those countries, as well as in
Northern India, it forms the chief articles of diet among the
richer classes. Barley is largely consumed by those who cannot
afford to eat wheat."*

In the preceding chapters it has been recognized that it is
quite possible to maintain life, a certain degree of health, and a
large measure of muscular strength, on dietaries whose protein
content is considerably below the ordinary standards.

When it was discovered that the teeming millions of Bengal
attained to a level of protein metabolism little more than one-
third of that provided in Voit's standard, it appeared as if there
was nothing more to be said on the subject, and that Chittenden's
conclusions, based on the results of laboratory experiments, and
carried out under somewhat artificial conditions, must be ac-
cepted as directly applicable to man under natural conditions
and over the whole period of life.

This was freely admitted at the time, and it was pointed out
that, so far as the knowledge derived from the analyses of the
urine goes, it bears out in every detail all that Chittenden had
contended for — viz., the feasibility of maintaining the body in a
condition of nitrogenous equilibrium indefinitely on a diet whose
protein value is one-third of that usually accepted as necessary
for the needs of the system.

On turning, however, from a contemplation of the mere
figures roughly representing the level of nitrogenous metabolism to
a study of the people from whom the figures were obtained, other,
and more important, points of view were forced on our attention.

* Strachey, "India, its Administration and Progress."

LOW PROTEIN DIETARY IN THE TROPICS 153

It was not, however, until evidence that appears absolutely
convincing had been accumulated, that we unwillingly resigned
our belief in Chittenden's deductions. His doctrine would be,
for many reasons, a most comfortable belief to hold ; it is not
necessary to enter into details of its numerous conveniences, but,
from an official standpoint, it would be of immense importance
to the State. In a country like India, where everything is on a
huge scale, the economy in the feeding of prisoners, famine camps,
plague camps, hospitals, and even armies in the field, with
their crowds of followers, to be effected by the acceptance of
Chittenden's standard would amount to very large sums, suffi-
cient to fill the heart of any Chancellor of the Exchequer with
delight.

It was, therefore, with many feelings of regret that we even-
tually turned from our original faith in the sufficiency of dietaries
low in protein to become firm believers in a doctrine diametrically
opposed.

When the average inhabitant of Bengal is dispassionately
examined from the standpoint of physique, health, resistance
to disease, and general manly characteristics, it became very
evident that other things had to be considered besides a nitrogen
balance and the mere fact of existence. What Hutchison
terms " degrees of health," and Waller " the state ot nutrition,"
must not be lost sight of. The former author states that a survey
of mankind will show that races which adopt dietaries deficient
in protein are lacking in energy. " Energy, however, is not to
be confused with muscular strength. A grass-fed cart-horse
is strong ; a corn-fed hunter is energetic. Energy is a property
of the nervous system, strength of the muscles. Muscles give
us the power to work ; the nervous system gives us the initiative
to start it. ... If protein food, therefore, be regarded as a nervous
food, a diet rich in it will make for intellectual capacity and
bodily energy, and it is not without reason that the more energetic
races of the world have been meat-eaters."

If this view is correct, then the Bengali, who lives largely on a
vegetarian diet of poor protein value, should exhibit these
characteristics to a marked degree. In the following pages we
shall discuss the evidence on the ill-effects to be expected from
existence on a low level of nitrogenous metabolism. Before
doing so, however, it will be of interest to cite the opinions of
some well-known authorities.

154 THE PROTEIN ELEMENT IN NUTRITION

Macaulay : " Whatever the Bengali does he does languidly.
His favourite pursuits are sedentary. He shrinks from bodily
exertion, and, though voluble in dispute, and singularly perti-
nacious in the war of chicane, he seldom engages in a personal
conflict, and scarcely ever enlists as a soldier. The physical
organization of the Bengali is feeble even to effeminacy ... his
limbs delicate, his movements languid. During many ages he
has been trampled upon by men of bolder and more hardy
breeds. His mind bears a singular analogy to his body. It is
weak even to helplessness for purposes of manly resistance ; but
its suppleness and its tact move the children of sterner climates
to admiration not unmingled with contempt. All those arts
which are the natural defence of the weak are more familiar to
this subtle race than to the Ionian of the time of Juvenal, or to
the Jew of the dark ages."

Strachey, commenting on the above passage, says :

" There have been many changes since Macaulay's time, and
among signs of increasing vigour one that is not without signifi-
cance has been the development of a taste for athletic sports
among the educated classes in the Government schools and
colleges — cricket, hockey, and football, especially the latter,
which is now played all over the province. This, however, is
true of only a small section, and the general description remains
much as Lord Macaulay presented it. It cannot, however, be
applied to the northern and eastern districts, where the majority
of the population is Mohammedan.

" The Mohammedan peasantry of the eastern portion of the
province are men of far robuster character than the Bengalis of
the western districts. It was among them that the sepoys who
fought under Olive at Plassey were chiefly recruited, and the
maritime districts supply thousands of intrepid boatmen and
lascars to the mercantile marine."

There is no doubt at the present time of the fact that sport
and manly exercises have taken a great hold of the Bengali
youth, which may be accepted as a great step forward in the
evolution of a more virile and energetic people. With this
change in customs a demand for a more concentrated diet than
rice is certain to arise.

The following saying concerning the Brahmins, who should be
vegetarians, exemplifies the effects likely to accrue from foods
deficient in protein :

LOW PROTEIN DIETARY IN THE TROPICS 155

"It is better to sit than to walk, to lie down than to sit, to
sleep than to wake, and death is the best of all."

Bearing in mind that the great outstanding problem in nutri-
tion is not the discovery of the minimum quantity of protein
on which a man can live, but the determination of the level of
nitrogenous interchange that is best for the efficiency, economy,
and general welfare of the body, it has appeared probable to us
that a survey of the food customs of the different races and tribes
in India, living under as nearly as possible identical conditions,
with careful observation of the effects on their respective de-
velopment and character, would go a long way in settling the
principal point at issue.

Such a survey we have made for the provinces of Bengal,
Behar, United Provinces, and partially so for some of the people
of the Punjab. We shall now take up the facts that have been
obtained, and discuss the evidence afforded by these facts on the
adequacy or inadequacy of low protein dietaries.

THE RICE-EATING BENGALI.

In Chapter IV., dealing with the protein metabolism of man-
kind, will be found a series of dietary studies carried out on some
of the inhabitants of Bengal. From the information there
furnished, the conclusion was arrived at that the average Bengali
of the rice-eating areas lives on a dietary whose protein value
is 55 grammes daily. This quantity was arrived at from practical
experimental work on different classes of individuals, and from a
careful collection of the average amount of foodstuffs consumed
by large numbers of Bengalis. Full information will be found
under the dietary studies referred to.

It was shown that the average amount of nitrogen excreted
in the urine by the average Bengali was about 6 grammes per
day. Making allowance for the nitrogen absorbed, but which
is dissipated or disappears in other ways than in the urine, this
would mean a low level of nitrogenous interchange, but higher
than that indicated by the urinary nitrogen. However, for the
sake of comparison and uniformity, we may adhere to Chitten-
den's method of computing the metabolism of nitrogen per kilo
of body weight ; the average Bengali will then show a nitrog-
enous interchange per unit of tissue practically identical with
that stated by Chittenden to be sufficient to meet all the protein

156

THE PROTEIN ELEMENT IN NUTRITION

requirements of the body — viz., 0-12 gramme of nitrogen.
;c These are perfectly trustworthy figures with a reasonable
margin of safety, and carrying perfect assurance of really being
more than sufficient to meet the true wants of the body, adequate
to supply all physiological demands for reserve protein, and able
to cope with the erratic requirements of personal idiosyncrasies."*
In dealing with the evidence of the effects of diets poor in protein,
we shall make use of the memoirs already published on the
subject.f

1. The Evidence afforded by a Study of the Urine and Blood.

Extensive observations were made on the chemical composition
of the urine and blood of Bengalis. At first the question was
taken up as a matter of urgent clinical importance to obtain
reliable standards for the normal quantities of the different
constituents, in order that rational deductions could be drawn
when any gross departure from the normal was met with in
pathological conditions.

Marked differences were obtained as compared with the
standards given for Europeans in the ordinary textbooks.

The following tables show the results arrived at :

THE URINE.

Constituents.

European.

Bengali.

Quantity

1,440 c.c.

1,200 C.C.

Specific gravity

1020

1013

Urea

13 grms.

Total nitrogen

18 g,,

6 „

Freezing-point
Chlorides

-2-5°C.
15-00 grms.

- 1-24° C.
10-000 grms.

Phosphates

3-50 „

0-918 „

Uric acid

0-75 „

0-452 „

Sulphates

2-50 „

1-880 „

Very decided differences were therefore found to exist between
the urine of the Bengali and that of the European. The im-
portant of these are — The lower specific gravity, the very much
less quantity of urea and of total nitrogen, and the higher
freezing-point, owing to the smaller quantities of different salts.

* Chittenden, loc. cit.

f Scientific Memoirs, Government of India, Nos. 34, 37, and 48.

PLATE

V

LOW PROTEIN DIETARY IN THE TROPICS

157

THE BLOOD.

Constituents.

Europear\.

Bengali.

Red blood-corpuscles

5,000,000

5,300,000

White corpuscles

6,000-8,000

9,000

Haemoglobin

100 per cent.

81 per cent.

Specific gravity

1054-1057

1055-1058

Proteins

19- 17 per cent.

18-23 per cent.

Total solids

21-13

20-12

Time of coagulation

4-7 minutes

If -2£ minutes

Systolic blood-pressure in brachial

artery

115-130 mm. Hg

90-115 mm. Hg

[The figures given for the red and white corpuscles are slightly
too high, as they include a number of observations made on
some members of the hill- tribes.]

The most marked differences between the blood of the Bengali
and the European are — The great deficiency in haemoglobin, the
smaller quantity of protein and total solids, and relatively, the
much shorter time of coagulation.

A certain number of observations were also made on the
alkalinity of the blood by Wright's titration method against
diluted normal sulphuric acid solution ; the alkalinity was found
to be distinctly higher than in Europeans.

The comparatively low blood-pressure of the Bengali is of
great interest from a clinical standpoint ; it has been regarded
as sufficient to explain the rarity of aneurism despite the marked
prevalence of syphilis and its ravage, as seen in the wards of
the hospitals.

From a survey of these results it will be evident that the
Bengali is on a much lower plane of metabolism than the Euro-
pean. The standards fixed for the different constituents are of
great importance in judging the degree of interchange of material
going on within the body.

From our standpoint chief interest centres in the figures

obtained for the urea and total nitrogen, and, as has been shown,

these indicate a nitrogenous metabolism of about 0-12 gramme

. of nitrogen per kilo of body weight, using the urinary nitrogen

as the criterion of protein interchange.

The condition of the blood is of equal interest.

It is evident from the analysis given that the protein content
of the blood is deficient in the Bengali. This is all the more

158 THE PROTEIN ELEMENT IN NUTRITION

remarkable when it is recognized that the corpuscular element is
quite up to the European standard. The percentage of the
floating proteins of the plasma is therefore even lower than
would appear from the figures. When we recollect that it is
from these floating proteins that the different nitrogenous tissue
of the body derive their nutrition, it will be abundantly apparent
that these facts have a very important bearing on the sufficiency
or otherwise of the diet, and more particularly of the protein
element of the diet.

In this connection it is interesting to note that a sparing
diet (1£ litres of milk daily) will cause a marked diminution in
the amount of serum-albumin and serum-globulin in so short
a time as one week.*

The blood-pressure has been found to be considerably lower
in the Bengali than is the case in the European — a condition
directly affecting the vigour and energy of the two races. The
factors in the causation of this lower scale of blood-pressure are,
probably, numerous. That difference in climatic conditions is
not the chief cause is shown by the fact that Europeans living
in the same climate do not exhibit such a low average blood-
pressure as met with in the Bengali. As would be expected,
the vasomotor system soon becomes acclimatized to the new
conditions, and regains its function of maintaining the tonicity
of the vessels in the area of peripheral resistance.

It is more than probable that the force of the heart- beat in
the Bengali is less than in Europeans — the cardiac muscle, like
the ordinary voluntary musculature, not being maintained in
such a high state of nutrition as that permitted by the superior
nutritive interchanges possible between the lymph and the
muscle cells in the European.

The very great deficiency in the haemoglobin value of the
blood in the Bengali is noteworthy. From a large number of
observations, both published and unpublished, the average
amount of haemoglobin is rarely found to exceed 80 per cent.
This means that, instead of each red blood- cell being in possession
of its normal amount of haemoglobin, it contains, on the average,
only about 75 per cent, of that quantity. This must have a
serious deleterious influence on the oxygen- carry ing capacity
of the blood.

From the evidence afforded by the chemical composition of

* Landau, " Osmostischen Druck dcs Blutes."

LOW PROTEIN DIETARY IN THE TROPICS 159

the blood, it may fairly be deduced that the diet — poor in nitrogen
— is the cause of the deficiencies. The blood in chronic under-
feeding is said not to show, as a rule, any great variations in
composition, being able to maintain its normal state under very
adverse circumstances ; but the changes that do occur are all
of the same type as those discovered in the blood of the Bengali.
V. Hoesslin states that chronic under- feeding influences the
total volume of the blood, as well as the mass of all the tissues,
and produces individuals who are poorly supplied with blood,
fat, and muscle.

It may, therefore, be concluded from these analyses that the
Bengali falls short of the European standards. His nitrog-
enous tissues are not given the option of drawing their
nutritive material from so rich a source, nor have they the
same opportunity of obtaining as free a supply of oxygen.
The effects of these conditions must be to modify very
markedly the physiological requirements of nutrition, and to
a considerable extent affect the growth, power of muscular con-
traction, and general metabolism of the individuals of such a
community.

While it is impossible to state dogmatically that these differ-
ences are entirely due to an insufficient supply of protein in the
food, it would appear to be the most plausible, and, so far as the
facts go, the only explanation.

We think we are justified in saying that a people who excrete
only 6 grammes of nitrogen daily in the urine live in a chronic
state of nitrogenous starvation, leading to a loss of body fat and
tissue protein, with the inevitable result of loss of vigour and
strength, and a comparatively low capacity for prolonged or
sustained muscular effort.

Extracts from the older writers have been already given
bearing on the working capacity of a rice-fed people, and we shall
have further evidence to produce on this subject. At present it
will be sufficient to state that the Bengali falls far short of the
ordinary European in this respect.

This is not due to any deficiency in the energy-producing
carbonaceous material, in which element their diet is very rich.
We hold, on the other hand, that it is due to a lack of muscular
development, and to the lower condition of vitality that must
follow from the presence of a composition of the blood ex-
hibiting the lower physiological limits of such necessary con-

160 THE PROTEIN ELEMENT IN NUTRITION

stituents as haemoglobin and floating proteins of the plasma,
combined with a lower scale of blood-pressure.

All these factors react not only on the muscular tissues, but
affect every tissue of the body, and particularly the delicate
mechanism of the central nervous system.

Mosso's work has taught us that fatigue is much more inti-
mately associated with changes in the central nervous system
than with mere fatigue of muscle substance, due either to accu-
mulation of waste-products or the consumption of the reserve
of energy-producing material.

It would therefore appear that, in a condition in which the
metabolic chemical changes of the central nervous system are
kept continually at a low level — as in the Bengali — fatigue will
be more easily and readily produced. Such is indeed in accord
with our everyday experience, and such we believe to be an
important factor in the causation of the lack of energy and vigour
which is a characteristic of the race.

2. The Evidence afforded by a Study of the Physical Development
of Bengali and Eurasian Students living under the Same
Conditions, but on Different Dietaries.

One of the large colleges in Calcutta kept a carefully tabulated
record for over twenty years of certain data concerning each
of its students — Bengali or Eurasian. The points observed were
the age, weight, chest-girth, and height, which were noted
every year for each student while he was a member of the in-
stitution. As a rule the students remained four years, but the
data for the fourth year being defective, only three years are
taken into consideration.

The dietaries partaken of by the two classes of students were
also available. The Bengali and Eurasian lived under the same
conditions, did the same work, and, as far as it is possible to
have it, everything connected with the two classes was strictly
comparable. The only difference between them may be summed
up in two words — race and diet.

With regard to race, the term Eurasian in the present con-
nection is meant to apply to all degrees of admixture from the
pure native Christian to the practically pure white of European
parentage. The great majority were considerably more native
than European. As we have already pointed out, the average

LOW PROTEIN DIETARY IN THE TROPICS 161

Eurasian, unless properly fed, does not develop physically into
a type much superior to the average Bengali. The conditions
are, as a rule, very complex, many of the Eurasians of Calcutta
being the descendants of mixed marriages between the Portu-
guese, French, and either native or Eurasian women. " Taking
the native Christian and Eurasian population as a whole (though
race cannot be invoked in the case of the former), the death-rate
is almost invariably lower than that of the general native popu-
lation. It is probable that the nature and variety of the food
play a considerable part in the production of these results."*

The diets on which these two classes lived while in residence
were as follows :

BENGALI^STUDENTS.

Protein . . 67-11 grms. |

Carbohydrates 548*73 „ V Heat value, 3,100 calories,

Fat .. .. 71-55 „ J

about 9*3 grms., or 14 per cent., of the protein being of animal origin.

EURASIAN STUDENTS.

Protein . . 94-97 grms. ]

Carbohydrates 467-00 „ \ Heat value, 2,830 calories,

Fat .. .. 56-20 „ J

about 42 grms., or almost 40 per cent., of the protein being derived from an
animal source, and more than half of the remaining quantity coming from
wheat.

From the details, published in the memoirf recording these
observations, it was shown that the Bengali students attain a
level of protein metabolism corresponding to the interchange
of 0-148 gramme nitrogen per kilo of body weight, while the
Eurasian students showed 0-203 gramme nitrogen, undergoing
metabolism for the same unit of tissue.

We have, therefore, two classes to contrast, represented by
568 Bengali and 126 Eurasian students, each class on a known
diet, each entering college in their seventeenth or eighteenth
year of age, living under exactly similar conditions as to the
climate, surroundings, and work, and each kept under medical
supervision during college life. The data obtained from year
to year afford reliable information concerning the degree of
physical development attained by the two classes.

This, in turn, will give us a trustworthy test of the adequacy
or otherwise of the dietaries as a whole, and more particularly —
the carbohydrate and fatty elements being admittedly sufficient

* " Imperial Gazetteer of India," vol. i.

t Scientific Memoirs, Government of India, No. 34, pp. 49 and 57.

162 THE PROTEIN ELEMENT IN NUTRITION

— will afford direct evidence on the effects of a relatively low
and medium level of protein interchange within the body.
What were the actual results ? From the records we find —

Bengali Students.

1 . There is an increase in the body weight, on an average over
the whole series, of 2 pounds only, when the weight on entrance
and weight at the end of the third year are compared.

2. On a comparison of the average weight on entrance and at
the end of the third year, 42-8 per cent, of the students show a
diminution in body weight ; only 15-3 per cent, gained weight
continuously during the three years.

3. On a comparison of weight on entrance and at the end of
the second year, 55-8 per cent, of the students show a diminution
of body weight.

4. The chest measurement practically remained stationary.

5. As would be expected from the age on entrance, the large
majority— over 80 per cent. — of all students show an increase
in height, ranging from 1 J to 2 J inches.

In the face of these results it can only be concluded that the
metabolism of 0-148 gramme nitrogen per kilo of body weight
was not sufficient to meet the nitrogenous needs of these Bengali
students, and, in from 30 to 40 per cent, of the 568 students
under observation, was insufficient to prevent a loss of formed
tissue protein as the diminution in body weight would appear
to mean. These results are in complete accord with the con-
clusion arrived at from a study of the blood, urine, and meta-
bolism of the students and servants of the Medical College,
Calcutta, in whom, on an average, a slightly lower level of
nitrogenous metabolism was found to be present.

Eurasian Students.

1. The average body weight over the whole series is — for the
first year, 116 pounds ; second year, 123 pounds ; third year,
130 pounds ; and fourth year, 135 pounds. That is, compared
with a maximum increase in body weight of 2 pounds in Bengali
students, there is an increase of 14 pounds in Eurasian students
over the same period.

2. On a comparison of weight on entrance and weight at the
end of the third vear, only 2 per cent, show a decrease, con-

LOW PROTEIN DIETARY IN THE TROPICS 163

trasted with a decrease of 42-8 per cent, in the case of the Bengali
over a similar period.

Practically 100 per cent, gained weight continuously during
the three years — a marked contrast to the 15-3 per cent, of
Bengalis who showed a continuous gain.

3. Less than 4 per cent, show a diminution in body weight
at the end of the second year, while 55-8 per cent, of the Bengali
students lose weight during this period.

4. In the Bengali the average chest measurement does not
alter, while the Eurasian students show the following averages :
First year, 33J inches ; second year, 34 inches ; third year,
34| inches. This is a considerable increase for the period during
which figures are available.

5. Growth in height is even more marked than in Bengali
students, practically everyone gaining considerably in height.

The dietary of these Eurasian students provided a minimum
metabolism of 0-203 gramme nitrogen per kilo of body weight,
whilst the heat value and carbonaceous elements were very much
lower than in the dietary of the Bengali students.

It is unnecessary to labour the comparison of the resulting
condition of these two classes ; the facts stated, gleaned from
the medical officer's records, speak with no uncertain voice, and
force the unbiassed mind to the conclusion that, while it is
possible to live on quantities of protein much below that fixed
almost universally at 100 grammes per day by the races and
people who are of greatest importance, any marked decrease
below this amount is likely to be accompanied with, and followed
by, a train of circumstances that are neither to the welfare nor
to the efficiency of the individual or the race.

The results obtained from a comparison of these two classes
of students are most important in appraising the merits or
demerits of diets low and relatively high in protein. It is not
a comparison of the physical development of Bengalis and
Eurasian, but a comparison of the two classes during a period
of three years of their lives, which they passed under exactly
similar conditions, the only difference being the quantity and
quality of their food, and, particularly, the difference in the
level of protein metabolism possible from their respective
dietaries.

We consider these results prove conclusively that, with a diet
poor in nitrogen, individuals are produced who are deficient in

164 THE PROTEIN ELEMENT IN NUTRITION

muscle, poorly supplied with blood, and who exhibit defective
development ; whilst with a liberal scale of protein intake results
the opposite of these are the rule.

It would further appear, as has been frequently shown in
feeding experiments on animals and in man, that general body
growth, and, more particularly, growth of the nitrogenous
tissues, increases pari passu with the degree of protein meta-
bolism per kilo of body weight. Exactly where the line is to be
drawn regarding the amount of protein essential in an ideal
diet we are unable to say, but we hold that the above figures
point undoubtedly to an increase in bodily vigour and develop-
ment taking place up to a nitrogenous metabolism of 0-203
gramme per kilo of body weight. This would correspond to
an interchange, for an average man of 75 kilos, of over 95 grammes
protein daily, and would mean a gross intake of over 100 grammes
albuminous material in the diet — 70 per cent, more protein than
Chittenden considers necessary.

3. The Evidence afforded by a Study of the Physical Development
and Endurance, Capacity for Work, and Expectation of
Life in the Bengali.

(a) The Body Weight. — From the records of over 2,500
observations on the weight of students, the average is just under
52 kilos.

Major Buchanan, I.M.S., made a very large number of weigh-
ments of prisoners in the Bengal gaols, from which he shows the
average weight to be 110 to 112 pounds (50 to 51 kilos).

This is about 25 per cent, less than the average weight of
the European. The Bengali is not sprung from an under-sized
race ; his stature and general build of body-frame compares
very favourably with that of Europeans. On the other hand,
the spareness and the deficient muscular development of the
average worker form a striking contrast to the condition met with
in the average European labourer. While it cannot be accepted
that a high average body weight is the all-important criterion
of physical fitness or power of resisting disease, other things
being equal, it will be generally admitted that good muscular
development is a desideratum in the efficiency and well-being of
a people. In connection with this question, it has been pointed
out that a close relationship exists between the physical and

LOW PROTEIN DIETARY IN THE TROPICS 165

moral development of men ; with a low physical standard we are
apt to get recruits not only small, but unsteady, wanting in
mental ballast as well as in muscular energy.

(b) The Height. — The average height of the adult male Euro-
pean, according to Quetelet's tables, is 5 feet 5 inches to 5 feet
6 inches.

The average height of Bengali students we found to be 5 feet
5J inches. Buchanan, from an analysis of his collection of
28,863 heights of prisoners, would place the average height
slightly under the above figures — viz., about 5 feet 4 inches.

(c) The Circumference of the Chest. — The average chest-girth
of our series of Bengali students works out to be just below the
minimum for admission into the British Army — viz., 33 inches.
It is, therefore, well below the average European standard.

Landois lays down a rule in judging good weight for height,
that normally developed individuals weigh as many kilos as
their length measures in centimetres, after subtracting the first
metre. This works out very well for the average height and
weight of Europeans — Europeans 168 centimetres in height
should weigh 68 kilos. When we come, however, to apply the
rule to Bengalis, whose average height may be taken at 5 feet
4 inches, or 162 centimetres, we find he falls far short of the
proper standard.

(d) Physical Endurance. — It is difficult to obtain anything
like fair comparative tests between the rice-eating Bengali and
the European labourer, but anyone who has seen the ordinary
Bengali at work will not require much in the way of statistical
evidence to convince him of the marked superiority of the
European. The same remark applies also, to a certain extent,
to a contrast of the working capacity of the Bengali and the
better-fed people of Behar, Eastern Bengal, United Provinces,
and Punjab. The picture of the feebleness, laziness, lack of
energy, and sleepiness of the working coolie could hardly be
overdrawn. We have seen three labourers, with, of course, a
sirdar or overseer, take eight days to loosen the surface of a drive
to the depth of 2 inches ; the total surface area of the drive
was roughly 200 square yards. Any ordinary European labourer
would have finished the work in a few hours. On watching them
for a time, it was noticed that the three took turns to work,
with long intervals, when they all sat or lay about, and after an
hour or so of this, one would disappear for a sleep, to be followed

166

THE PROTEIN ELEMENT IN NUTRITION

later by the remaining two in turn ; the overseer slept most of
the time, making no attempt to keep them at their work.

(e) Capacity for Work. — The following table, modified from
the report on factory labour in India, brings out clearly the
relative productive capacity of the English and Indian worker :

•

England.

India.

Operatives per 1,000 spindles . .

4-2

28

,, ,, looms

43

125

Annual out-turn of yarn per operative

7,736 Ibs.

4,000 Ibs.

Weekly out-turn of cloth per operative

767 yds.

240 yds.

Working hours per week
,, ,, ,, year

55£

2,775

80
4,120

Indian labour is lacking in continuous application, punctuality,
energy, and regularity. Men have to be employed in India for
work that women will do in England. The Indian workers have
little skill or education, and consequently make much waste ;
their sense of discipline is imperfect ; their attendance irregular ;
and they take long intervals for rest, smoking, etc. (Commercial
Supplement of the Times).

The coal-mines of Europe and Bengal are perhaps the best
comparative test of the capabilities of the two classes of workers.
The conditions are all in favour of the Bengali ; he cuts coal from
thick seams, the mines are at no great depth, and a large pro-
portion are worked with inclines, no shafts being necessary.
The following figures give some idea of the output per man
yearly :

America
England
Germany

Bengal

589 tons (mining simple).
300 „
243 ,,

600 ,, (lignite quarries).
80 ,

The physical conditions are altogether in favour of the Bengali,
and the result is an out-turn barely 27 per cent, of that of the
European.

We might multiply instances of the inferior capabilities of
the native workmen, but it is so well recognized by all who
have had dealings with them that further evidence is un-
necessary.

It may be accepted that the rice-eating Bengali on a diet

LOW PROTEIN DIETARY IN THE TROPICS

167

poor in nitrogen is incapable of performing a really hard day's
work ; the explanation can only be that the deficient nitrog-
enous intake does not permit of the development of the muscular
tissue necessary for the carrying out of severe labour.

The carbohydrate element of the diet is present in abundance
for the supply of the required energy, but the muscular tissue,
essential for the dissipation of that energy in the form of work,
is largely lacking.

(/) Expectation of Life. — The following table,* compiled by
Mr. Hardy from census and local mortality statistics, may be
taken to give an approximately accurate estimate of the expecta-
tion of life at different ages, with the corresponding English
figures for comparison :

Expectation of Life.

Age in Years.

India, 1881-1891.

England, 1881-1891.

Males.

Females.

Males.

Females.

0 ..

24-6

25-5

43-7

47-2

5

37-1

36-1

52-7

54-9

10

35-5

34-4

49-0

51-1

15 ..

32-3

31-7

44-5

46-5

20

29-2

29-3

40-3

42-4

25

26-3

27-0

36-3

38-5

35

21-1

22-4

28-9

31-2

45

16-5

17-9

22-1

24-0

55

12-2

13-2

15-7

17-2

65

8-2

8-7

10-3

11-3

Between fifteen and thirty-five years of age the probabilities
are from 36 to 38 per cent, for males, and from 34 to 48 per cent,
for females, less favourable in India ; the difference at birth
amounts to 79 and 85 per cent, respectively.

The mortality rates per 1,000 are also much higher in India
than in European countries. In Bengal the " probable true
normal rate " (1888-1891) was 44-8 per 1,000, and for India
39-6. For the same period in England and Wales the death-
rate was 19-1.

It is interesting to note that the figures for Hindus and
Mohammedans show that the death-rates, under similar con-
ditions, are in favour of the latter. This is the more remarkable

* " Imperial Gazetteer of India," vol. i., p. 515.

168 THE PROTEIN ELEMENT IN NUTRITION

as the Mussulmans, as a body, are often included in the poorer
sections of the community. In the Native Army, during the
five years 1895-1899, the mean death-rate of Hindus was 8-8 per
1,000, while that of the Mohammedans was only 3-6.

Also, the available records of mortality from plague afford
testimony to the greater power of resistance which Mussulmans
enjoy. As already stated, Eurasians and native Christians have
invariably a lower death-rate than the general native popula-
tion ; these results are ascribed by the author of the article as
largely due to differences in the nature and variety of food.*
The Mohammedans, Eurasians, and native Christians are all
meat - eaters to a much greater extent than the Hindu, and
animal food in almost any form raises the level of nitrog-
enous metabolism in a way even the best of cereals fails
to do.

Further evidence of the inferiority of the Indian, and
more particularly of the Bengali, as regards the expectation
of life, is afforded by information collected from insurance
companies.

The greatest precautions are taken in the selection of Indian
lives ; even then, those accepted are rated up 33 per cent, higher
than Europeans in Europe.

Compared with Europeans in India, some companies add
five years to the Bengali's age — i.e., a Bengali of thirty
years pays the premium of a European of thirty-five years
of age.

Some companies only accept Bengali lives when insured for
a limited number of years ; the fewer, and therefore the higher
the premiums, the more welcome the policy. An endowment
policy is rarely granted which matures above the age of fifty
to fifty-five years. The explanation of this condition is that
policies beyond these ages were found not to pay, death occurring
before sufficient premiums had been paid to cover the amount of
the policy.

Mr. A. T. Winter, F.I.A., states : " The most eligible class of
natives are assurable at the same rates as Europeans in India,
provided their age at entry does not exceed forty."

An important paper on life insurance in India by Dr. Adrian
Caddyf gives some information on the physique and general

* "Imperial Gazetteer of India," vol. i., p. 515.

| " Life Assurance in India," Life Assurance Medical Officers' Association.

LOW PROTEIN DIETARY IN THE TROPICS 169

health conditions of the classes who are able to afford such
provision for the future. These classes are, of course, drawn
from those who are in affluent circumstances, or who are in
receipt of a steady income more than sufficient to cover the
ordinary expenses of family life. As would be expected, they
belong to the middle classes, who are above indigence, and the
well-to-do people — that is, the very people who can afford to
live on a liberal diet. We have given in Chapter IV., Dietary
Study 3, some idea of the food of these classes, and reference
to the facts will show that the diets are well supplied with
assimilable protein — amongst the better classes, reaching the
almost universal average of 100 grammes of protein in the daily
food.

The facts supplied by Dr. Caddy's paper on over 6,000 cases
personally examined, afford a good means of comparing the
physical development of those who are properly fed with the
average Bengali who lives on the lower limits of protein meta-
bolism.

Dr. Caddy's results show that —

1. The average height of the assurable Bengali is practically
identical with those of the poorest physique in England. " Not-
withstanding this, the insured Bengali is always considered to
be a select person among the whole race, the vast majority of
natives in India being quite uninsurable owing to their poverty
and illiteracy."

2. The average weight for height corresponds very closely
to the European standard for Europeans in India, though con-
siderably less than that for Europeans in Europe, as indicated by
Robertson's or Hutchison's tables.

It follows from this that the bony frame of the assurable
Bengali is only slightly lighter per unit of height than that of
the European — a very different condition from that which
obtains amongst the average working-classes of Bengal.

Thus, from data derived from over 30,000 weighments of
Bengalis, the average weight was found to be 50J kilos, whilst
the average height over a similar number of measurements
was 5 feet 4 inches (prisoners) to 5 feet 5J inches (students).
That is, whilst the height approximates fairly closely to the
stature of the poorer classes of Europeans, the average weight
is 25 to 30 per cent, below the European or American
standard.

170 THE PROTEIN ELEMENT IN NUTRITION

3. Causes of rejection among Europeans and Bengalis :

Of 1,799 pure Europeans, 8 per cent, loaded and 6 per cent, declined

= 14 per cent.
Of 335 India-born Europeans, 8-95 per cent, loaded and 11-94 per cent.

declined = 20-89 per cent.
Of 317 Eurasians, 7-88 per cent, loaded and 15-45 per cent, declined

= 23-33 percent.
Of 3,483 Bengalis, 8-38 per cent, loaded and 16-53 per cent, declined

= 24-91 per cent.

I

Cause of Loading or Rejection.

Europeans
(1,799 Cases).

Bengalis
(3,483 Cases).

Inferior physique
Obesity

1-55 per cent.
2-11

5-36 per cent.
5-34

Glycosuria

0-61

3-24

Albuminuria

1-22

1-98

Sundry diseases

3-39

4-96

Hydrocele

0-22

5-10

The value of these figures from our standpoint is not so much
that they afford a basis of comparison of the Bengali with the
European — the European in India is generally a selected in-
dividual who has been passed as medically fit before leaving
England — their interest really lies in the comparative informa-
tion they afford on the physique, resistance to disease, and general
well-being of the classes of Bengalis who are able to provide
themselves with a liberal protein dietary, as contrasted with the
conditions that obtain in the great mass of the population living
at the level of nitrogenous interchange which Chittenden zc
strongly advocates as the optimum.

Dr. Caddy's figures bear out in a remarkable manner the
statement made by us years ago, that the average Eurasian,
unless following European customs and ideas on diet, was
physically very little superior to the vegetarian Bengali, so that,
whatever initial superiority his share of European blood may have
conferred on him, it becomes entirely lost as a result of existence
on diets similar to the native inhabitants, diets which are gener-
ally deficient in assimilable protein. The effects of a rational
diet supplying about the European standard of protein material
were strikingly brought out in our analysis of the evidence
afforded by the observations on the physique of Bengali and
Eurasian students under Heading 2 of this chapter.

The same effects have been observed in the development
shown by Anglo-Indian and Eurasian students in residence for

LOW PROTEIN DIETARY IN THE TROPICS 171

four or five years in another college in Calcutta. A full account*
has already been published ; it is, therefore, unnecessary to
enter into details. The facts are : These students enter as
mere boys of up to sixteen years of age ; during the four years
or so of residence they develop into strong, healthy men, quite
up to the average European standard in physique. Their
dietary permits of a metabolism of 0-196 gramme nitrogen per
kilo of body weight daily. Contrasted with their native fellow-
students who live on a much lower protein dietary, the account
already given of their marked success in the intercollegiate
athletic sports, and the fact that, although few in number
compared with the number of Bengali students, the college
team was almost entirely selected from them, make abundantly
obvious the determining influence of diet, and particularly pro-
tein on the growth and well-being of mankind. The two classes
enter college about the same age, live in the same climate and
under very similar conditions ; further, as we pointed out some
years ago, and this has been corroborated by Dr. Caddy's figures,
there is no racial reason why the Bengali, if he were properly
fed, should not be as well developed and as efficient as the
Eurasian ; the results, however, at the end of their college
career are very different.

We may conclude, therefore, that whether we compare the
average Bengali with the European, Eurasian, or with the
Bengali who obtains a fairly liberal allowance of protein ;
whether we contrast students living under similar conditions, ex-
cept those pertaining to diet ; whether we study the physical de-
velopment of the Bengali, his endurance, capacity for work, or
expectation of life — the results of observation and investigation
all point in the same direction. The evidence forces on us the
practical lesson that the generally accepted level of nitrogenous
interchange cannot be decreased to any appreciable extent
without damage to the growth, maintenance, and repair of the
protoplasmic tissues, and a lowering of the general efficiency and
well-being of the body.

4. The Resisting Power to Disease and Infection.

Chittenden holds that the smallest amount of food that will
serve to maintain bodily and mental vigour, keep up bodily
strength, and preserve the normal power of resistance to disease,

* Scientific Memoirs, Government of India, pp. 53 to 56.

172 THE PROTEIN ELEMENT IN NUTRITION

is the ideal diet. This amount, he believes, is fully met by a
daily metabolism equal to an exchange of 0-12 gramme nitrogen
per kilo of body weight. Any excess beyond this amount
imposes just so much of an unnecessary strain upon the organism,
and more especially on the excretory organs, placing on them
the needless burden of the elimination of an extra quantity of
waste products, which is liable to endanger their integrity and
possibly result in serious damage.

The important point, from our present standpoint, is the
amount of food that " preserves the normal powers of resistance
to disease." The Bengali exists on the actual amount of protein
Chittenden declares to be the optimum, and should, therefore,
exhibit those " many suggestions of improvement in bodily
health, of greater efficiency in working power, and greater
freedom from disease," which Chittenden believes to be amongst
the merits of diets poor in protein.

It may be stated at once that there is absolutely no evidence
to support the contention that the elimination of the waste
products of the average protein dietary throws any strain on
the kidneys — in fact, the evidence would tend to point to exactly
the opposite conclusion — viz., that- there is greater danger of a
condition of malnutrition of the renal epithelium from the
lowered or impoverished state of the blood which accompanies
a diet poor in protein. In support of this view we may point
out —

1. The great prevalence of kidney disease in Bengal, despite
the very low level of nitrogenous interchange exhibited by the
great mass of the population.

2. The very common association of albuminuria with the
ordinary dietetic form of glycosuria found in Bengal, even in
the earlier stages of the disease. Dr. Chuni Lai Bose* states
that 65 per cent, of his series of 325 cases of glycosuria showed
evidence of kidney damage . In Europeans glycosuria is not accom-
panied by albuminuria in anything like such a high percentage of
cases. We believe that the explanation rests largely with the
nutritive power of the plasma in the two classes of people, the
lowered state of vitality of the renal epithelium, from the poor
condition of the blood, rendering it more easily damaged in the
Bengali, and less able to withstand the irritating effects of sugar
elimination.

* Scientific Memoirs, Government of India, No. 34, pp. 63-67. This point
is discussed in more detail.

PLATi

LOW PROTEIN DIETARY IN THE TROPICS

173

3. A similar common association of albuminuria with anaemia
is met with in Bengal, in all probability due to degenerative
changes in the kidney epithelium, from an impoverished condition
of the blood. This also does not occur to anything like the same
extent in the anaemias of Europeans. It would therefore appear
that the resisting power of the renal cells is on a lower level in
the rice-eating Bengali than in the better-fed races.

In order to obtain information on the effects of a low protein
on the incidence of renal disease, we have been able to collect
some valuable evidence. Thus —

Cases discharged or Dead from the Medical College
Hospital, Calcutta, during Twenty-Two
Months from June, 1905.

Total Kidney
Cases discharged
during the
Same Period.

Percentage of
Kidney
Cases to Total
treated.

Total, 3,602

120

3-33

Europeans, 1,320

26

1-97

Natives, 2,282

94

4-10

St. Thomas's Hospital, 1904 : Total, 2,589 . .

136

5-25

St. Bartholomew's Hospital, 1904 : Total, 2,512

95

3-79

The most recent figures for the Medical College Hospital,
including only medical cases of organic disease of the kidney,

are —

Total Admissions for Three Years, 1909-1911.

Organic Disease
of Kidneys.

Percentage of
Kidney Cases to
Total treated.

Europeans, 4,568
Natives, 10,343

70
244

1-53
2-36

We are indebted to Major Leonard Eogers, I.M.S., C.I.E.* for
some most interesting figures obtained from an analysis of the
post-mortem records of the Medical College Hospital, Calcutta.
No. VI. of his series of papers deals with diseases of the kidney.
He finds that in 4,800 bodies examined, serious renal disease was
present in 4 per cent., and was the primary cause of death in
.over 3 per cent, of all cases. He states that renal disease is
relatively a not very common cause of death, judging from the
post-mortem records, although there appears to be no lack of
cases in the wards. In a more minute analysis of 1,000 recent
post-mortems, most of which were performed by himself, 6 per
cent, showed well-marked disease of the kidneys, mostly con-

* " Gleanings from the Calcutta Post- Mo item Records," Indian Medical
Gazette, 1909-1912.

174 THE PROTEIN ELEMENT IN NUTRITION

tracted or granular in nature, whilst another 5 per cent, exhibited
minor pathological changes.

The race incidence of renal disease, as demonstrated by these
records, is of interest from the standpoint of the influence of
diet. In 4,280 post-mortems the following results were ob-
tained :

Race.

Parenchymatous
Kidney.

Granular Kidney.

All Diseases.

Hindus
Mohammedans
Europeans

54*1 per cent.
24-3
16-2

65 per cent.
19
15

67 '4 per cent.
20-5
8-2

These figures show that kidney disease as a cause of death is
twice as great, in proportion to their numbers, amongst Euro-
peans as amongst Hindus, the Mohammedan occupying an inter-
mediate position. The Hindu dies considerably less often from
parenchymatous nephritis than either the Mohammedan or
European.

These results are at variance with those obtained from the
hospital statistics on the incidence of renal disease as met with
in the wards, and as found by Dr. Caddy in life insurance ex-
amination. The discrepancy is, at least in part, accounted for
by the fact that the earlier records contained a large number
of post-mortems on European sailors amongst whom, owing to
extreme prevalence of syphilis, alcoholism, and scurvy, renal
disease was very prone to occur. Accepting the figures, how-
ever, as worked out by Major Rogers, they undoubtedly point
to renal disease being a more common cause of death amongst
the meat-eating Europeans than amongst the largely vegetarian
Hindus ; so far as the deductions are valid, they would tend to
support Chittenden's contention that the kidneys may suffer
in conditions where a large amount of waste has to be con-
tinuously eliminated. With regard to this point Major Rogers
states that the average age of death is much higher in the
European than in either of the other races, and that naturally
granular kidney would be present in a higher percentage of
European deaths.

We may sum up the evidence from this standpoint by stating
that in a country where scarlet fever is unknown, the prevalence
of renal disease is amazing, and would not appear to support
the view that with diets low in protein disease of the kidney

LOW PROTEIN DIETARY IN THE TROPICS

175

is less likely to occur. Renal disease is very common in Bengal,
and, as met with in the wards of the hospital and out-patient
department, is distinctly more prevalent amongst the low protein-
consuming Hindu than amongst the more highly fed European.
With regard to the power of resistance to other pathological
conditions, as, for instance, septic infection, acute inflammatory
processes, recovery from shock, etc., Rogers's researches supply
information and evidence which have been hitherto entirely
lacking. We stated in a former publication on this subject
that there was a general consensus of opinion amongst medical
men that natives stand acute infections such as pneumonia,
plague, cholera, etc., badly. The evidence obtained from post-
mortem records bear out this opinion in a remarkable manner.
Thus, the reports of 4,800 post-mortem examinations show —
1. That there are nearly twice as many Mohammedans over
the age of fifty as Hindus, and almost three times as many
Europeans. The figures are :

4,800 Post-mortems Show

Hindus.

Mohammedans.

Europeans.

Over 50 years of age . .

5*7 per cent.

10-4 per cent.

16'3 per cent.

This corroborates the evidence already adduced on the expecta-
tion of life for the different races, and shows that the low protein-
consuming Hindu dies off earlier than the better-fed Moham-
medan and European.

2. The race incidence of death from acute lung diseases,
excluding tubercle, demonstrates that Hindus are very much
more liable to die of acute inflammatory lung trouble than either
Mohammedans or Europeans. Thus 74-6 per cent, of fatal lung
diseases were in Hindus against 67-4 per cent, of that race in
the total number of deaths. The Mohammedan deaths were
only 1 per cent, below the normal, while that of Europeans was
3-4 per cent, against a normal rate of 8-2 per cent, of deaths.
The figures are —

Race.

Deaths from all
Diseases.

Deaths from Acute
Lung Diseases.

Total Deaths.

Hindus
Mohammedans . .
Europeans

67 -4 per cent.
20-5

8-2

74-6 per cent.
19-4
3-4

} 4,280, extending over
a period of the last
forty years.

176 THE PROTEIN ELEMENT IN NUTRITION

Rogers states : " This marked difference in the incidence of
lung diseases, extending over so many years, must be racial in
character, and points to a lesser resisting power to these acute
bacterial diseases of the largely vegetarian Hindu, as contrasted
with their meat-eating Mohammedan brethren, while Europeans
exhibit still greater resistance to these deadly affections."

3. Rogers has worked out the figures also for another acute
bacterial infection — viz., acute meningitis. The records of
4,800 post-mortem examinations show that 75 per cent, of the
fatal cases of acute meningitis occurred in Hindus, against
674 per cent, of that race in the total records, while only 17-5 per
cent, were Mohammedans against 20-5 of that race ; Europeans
are again well below the normal. The figures are :

Race.

Deaths from Acute
Meningitis.

Deaths, all Diseases.

Hindus
Mohammedans
Europeans

75-0 per cent.
17-5
5-0

67 -4 per cent.
20-5
8-2

4. Cholera is distinctly more fatal in Hindus than in Moham-
medans, and is less frequently the cause of death in Eurasians.
Europeans, on the other hand, get a very much more severe
type of the disease than either natives or Eurasians, and the
mortality is proportionately high.

Rogers' s analysis of these post-mortem records are of very
great interest from the standpoint of the effects of diet on the
resisting powers of the different races to bacterial infection.
Space does not permit us to enter into further details ; the
general effect of the evidence is practically what would be
expected from the differences in dietetic customs — viz., the
Hindu exhibits a decidedly poor degree of resistance to infection
in comparison with the higher protein-consuming races. This
is particularly marked during the frequent outbreaks in India
of acute epidemic diseases, such as plague, cholera, smallpox,
different septic conditions, etc.

The Hindu suffers more from gall-stones, much more
commonly from cirrhosis of the liver, and all acute inflammatory
processes ; on the other hand, owing to his low feeding and its
accompanying deficiency in blood-pressure, he dies less often
from aneurism and cerebral haemorrhage than the meat-eating

LOW PROTEIN DIETARY IN THE TROPICS

177

Mohammedan and European. Bright's disease, which, accord-
ing to Chittenden's views, should be practically non-existent
in the Hindu in contrast to the Mohammedan or European,
is exceedingly prevalent. Atheroma and granular kidney are
practically as common in the Hindu as in the Mohammedan,
the slight difference in the figures being completely explained by

RICE-EATING BENGALI COOLIES.

the greater incidence of these conditions in the later decades of
life, during which a much larger proportion of Mohammedans
are alive. The figures show —

Race.

Deaths from Granular
Kidney.

Deaths, all Diseases.

Hindus
Mohammedans

65-0 per cent.
19-0

67*4 per cent.
20-5

NOTE. — Atheroma present : Hindus, 26-8 per cent. ; Mohammedans,
29-2 per cent.

Taking the total deaths after fifty years of age, the position is
reversed — 50 per cent, of Mohammedans show marked atheroma
against over 52 per cent, of Hindus.

12

178 THE PEOTEIN ELEMENT IN NUTRITION

Such are some of the facts gleaned by Major Rogers from the
post-mortem records of the Medical College Hospital, Calcutta.
They bear out in a most remarkable manner the results of other
lines of investigation on the ill-effects to be expected when a
tribe or race subsists on the lower limits of protein interchange.
The lessened expectation of life, decreased resistance to disease
and infection, earlier onset of the marked evidences of tissue
degeneration and senility, are conditions that would be antici-
pated in a people who exhibit such slackness, want of vigour,
tonelessness, general slowness of reaction, and other physio-
logical attributes difficult to describe, detect, and measure, which
form some of the distinguishing characteristics of the working
population of Bengal. Self -absorption, introspection, want of
interest in the incidents of everyday life, little power of atten-
tion, observation, or concentration of thought — these are some of
the attributes of all but the better classes and better fed of the
Bengalis.

In the following chapter we shall take up some of the other
tribes and races and study the influences of dietaries more liberal
in protein on the physical development and general efficiency of
their average representatives.

CHAPTER VIII

THE EFFECTS OF THE LEVEL OF PROTEIN

METABOLISM ON THE PHYSIQUE AND GENERAL EFFICIENCY
OF DIFFERENT TROPICAL TRIBES AND RACES

WE have now discussed the general effects of a low protein
dietary, as exemplified by the Bengali, and showed that, from
whatever point of view taken, the conclusion must be arrived
at that his physique, capabilities of work, health, and resistance
to disease, all suffer on account of his low level of protein
metabolism. Before proceeding to an examination of the other
tribes and races, it may be well to pause and ask ourselves the
question : May there not be other factors beside the meagre
protein interchange that must be taken into account before the
condition of defective nutrition can be ascribed to the protein
element of the Bengali's diet ?

Although our views on the relationship of food to physical
development have been published for a number of years, so far
only two serious attempts have been made to explain the acknow-
ledged inferiority of the Bengali as due to causes other than
those related to diet. One of these we have already referred to
in Chapter IV. Chittenden believes the conditions met with in
the Bengali are due to an ill-balanced, unphysiological character
of his diet, and not to the limited amount of protein interchange
possible from it. We have already discussed the misconception
he was labouring under, and met his objections by simply
pointing out that the average dietary of the great mass of the
population is not of the ill-balanced type he considers it to be.
The misconception evidently arose in his mind from our con-
demnation of the Bengal Gaol dietaries, which are in reality in
no way representative of the diets of the people. We demon-
strated, judging by his own standard of what a well-balanced
diet should be, that the ordinary diet of the great bulk of the
population does not compare unfavourably in the amount of

179

180 THE PROTEIN ELEMENT IN NUTRITION

unabsorbed protein with the diets by means of which he obtained
his unique results. We need not refer further to this criticism,
as it does not apply to the people whom we are discussing, and it
really only holds good for the gaol dietaries, as pointed out by
us at the time.

The second and more important criticism is that made by
Dr. Kellogg. His objections have been of very great service to
us, and have materially assisted in crystallizing our ideas as to
the best means of obtaining irrefutable evidence on the adequacy
or inadequacy of diets low in protein. Dr. Kellogg' s words were :
"The weakest part of the report* from my standpoint is the
remarks which the investigator makes in relation to the defective
nutrition resulting from the low protein dietary. I do not think
it is at all fair to attribute the lack of endurance often seen among
the Indians to the low protein diet. There are so many factors
which certainly should be taken into consideration. Among
these are their sexual excesses, the depressing effects of the very
hot, damp climate in which they live, and which predisposes to
lack of exercise, the injurious effects of excessive prolonged ex-
posure to the actinic rays of the sun, the cause of debility to
which Professor Woodruff of the United States Army has been
calling attention with some considerable show of evidence. Still
another factor of importance is the immature age at which these
people usually marry. Many of the Indians, however, are strong
and robust people. I understand that an Indian regiment made
up entirely of natives is the finest lot of men in His Majesty's
Service."

It will be readily admitted that, unless these points can be
successfully met, there must remain a considerable degree of
doubt as to how much of the ill-effects can be ascribed to the
dietetic conditions, and how much to the disabilities enumerated
by Kellogg.

We agree that the causes he advances have undoubtedly an
influence in retarding growth and lowering the general standard
of physique, and if there were no means of estimating their
influences, it would be impossible to state that they were not
quite sufficient to account for the poor physique of the Bengali.
Considerations of space forbid us discussing these objections in
the way we should like to do. A certain amount of information
will be found on the subject in a memoir dealing with the gaol
* Scientific Memoirs, Government of India, No. 34.

TROPICAL TRIBES AND RACES 181

dietaries of Bengal, and much valuable material on their influences
has been collected in Risley's book, " The People of India," and
in the first volume of the " Imperial Gazetteer of India." From
the point of view of their effects on physical development it is
unnecessary for us to attempt to measure and appraise their
value for the following reason :

By contrasting the nutritive conditions of the different tribes
and races— in which the several factors enumerated by Dr.
Kellogg are common to all, the level of protein interchange
forming the main point of difference — we can eliminate the
influence of the sun's rays, early marriages, climate, sexual
excesses, etc. — in fact, everything except the role played by diet —
in the several factors that go to make one class superior to another,
or one tribe or race superior in efficiency to another tribe or race.

In the following pages we shall, therefore, attempt to gain
definite and precise information on the effects of diet per se by
contrasting the developmental conditions obtaining amongst
the people, tribes, and races who are in every respect, except with
regard to diet, strictly comparable.

We have already given strong evidence of the determining
effects of diet on different classes of Bengalis, subject to all the
different causes advanced by Kellogg as fully accounting for
poor physique. In this connection nothing could be more con-
vincing than a comparison of the average weight, height, and
chest measurement of the ordinary working population and
the physical development of the better fed, assurable classes as
evidenced by Dr. Caddy's records. Similar results were obtained
from observations on students of the same and different colleges,
living under similar conditions, but regarding whom the levels
of protein interchange differed considerably. A full account of
these observations will be found in the preceding chapters, so
that it is unnecessary to do more than call attention to them in
the present connection.

The rice-eating Bengali may be contrasted with his nearest
neighbours, the people of Behar, as the conditions of life for these
people are very similar. From work done on the protein metabo-
lism of the Behari,* it was shown that the level of nitrogenous
interchange is at least 20 per cent, higher than is the case in the
Bengali. In accordance with this the Behari shows a much
superior physical development, greater capabilities for muscular
* Scientific Memoirs, Government of India, No. 38, pp. 206-209.

182 THE PROTEIN ELEMENT IN NUTRITION

exertion, and a distinctly greater degree of vivacity, tonicity.
and energy. The body weight, and what is really of most
importance, the actual quantity of protoplasmic tissue, is also on
a higher scale of development. The evidence shows that the
Behari is a stronger, healthier, and more capable individual in
every respect than the Bengali, when the same classes of each,
such as the working classes, are compared. The only explanation
of this finding, from Dr. Kellogg' s standpoint, would be the
influence of climate. Behar is drier than Bengal, has a lower
temperature in the cold season, but is much hotter in the
summer.

The differences in climate, however, are only marked between
the extremes of Bengal and Behar, whereas whenever we find a
change from a diet of rice and dal to one containing wheat
in addition, the superiority of the Behari at once becomes
evident.

The same condition is met with in contrasting the rice-eating
Bengali with those of the more eastern parts of the province,
where fish forms an important element in the dietary. In this
comparison even the influence of a slight difference in climate is
eliminated, as the eastern districts are even more moist than
those around Calcutta.

All the factors that Kellogg lays stress on are present in
Behar, Lower Bengal, and Eastern Bengal, and yet it is well
recognized that the Behari and native of Eastern Bengal is a
much superior man physically to the inhabitant of the Presidency
districts. The only explanation that will withstand the test of
critical observation is that based on differences in diet. This
difference is the substitution of a certain amount of wheat for
rice in the case of the Behari, and of wheat and fish in the case of
the people of Eastern Bengal, or — translated into its ultimate
effects — the metabolism of from 8 to 9 grammes of nitrogen daily
for the average Behari and Eastern Bengali, in place of a
metabolism of from 6 to 7 grammes of nitrogen for the rice-
eating inhabitant of Lower Bengal and Orissa.

It may be concluded, therefore, that, so far as the evidence
obtained by contrasting the different classes of Bengalis, and
Bengalis of the same race, but living in different districts and on
different scales of nutrition, goes, diet and the level of protein
interchange play the principal part in the formation of their
respective characteristics, and is the principal factor in the

TROPICAL TRIBES AND RACES 183

building up and maintenance of the nitrogenous tissues of the
body.

Before passing from the inhabitants of the plains of Bengal it
is necessary to refer to the last part of Kellogg's criticism — viz.,
" Many of the Indians, however, are strong and robust people.
I understand that an Indian regiment made up entirely of natives
is the finest lot of men in His Majesty's Service." These remarks
were made in connection with our work on the metabolism of the
rice-eating Bengali, and their effect is to afford another example
of the loose way in which evidence on the sufficiency of vege-
tarian diets is collected. The line of reasoning is easily followed :
rice is the staple food of the Indian ; the physique and manly
qualities of Indian regiments compare very favourably with that
of other countries whose soldiers are accustomed to meat, and
are high protein feeders ; therefore a vegetable diet and a low
level of protein metabolism is quite as good, if not actually
superior, to a mixed dietary and a higher level of nutrition.
The true facts, as exemplified in the selection of soldiers for the
[ndian Army, demonstrate the fallacy of this reasoning, and afford
still further evidence of the importance of a high standard of nutri-
tion in the formation of the qualities and instincts of the soldier.

The Bengali has never, so far as we are aware, in modern times
been recruited for the fighting line, and although many regiments
are termed Bengal Infantry, Bengal Cavalry, etc., not a single
man carrying a rifle could claim Bengal as his place of birth.
We have no desire to labour this point unduly, but the question
arises, Why is the Bengali unfit for the fighting line when other
inhabitants of the great Gangetic Plain, stretching from the
north-west in the Punjab to the sea in Bengal, exposed to, and
suffering from, practically all the disabilities enumerated by
Kellogg, but on a superior dietary, are capable of exhibiting the
firmest courage, and maintaining untarnished the great fighting
traditions of their race ? Thus, there is the Sikh, famous
thoughout the world for his endurance and manly qualities, an
inhabitant of the hottest plains of India, yet a man of splendid
physique and full of energy ; the Dogra, the Jat, Rajput, all
well known for their own special qualities on the Indian frontier,
or where courage, determination and endurance are called for.
Even in the various classes of these and allied races, differences
in physique, muscular vigour, hardiness, and all those qualities
that go to make up the perfect soldier, can be detected.

184 THE PROTEIN ELEMENT IN NUTRITION

We believe that diet, and particularly the level of nitrogenous
metabolism attained, has an immense influence on the formation
of those desirable characteristics so well exemplified in the races
whence is drawn our best fighting material. Further, although
we have made little or no attempt to advance arguments for or
against vegetarianism, it will be found that those races, whether
of the hills or the plains, who are distinguished above all others
for their martial qualities, are never vegetarians, but, on the
contrary, usually large meat-eaters. The Sikh lives on wheat,
other cereals, milk, and meat, particularly pork, of which he is
specially fond. The Kajput, Pathan, Baluchi, etc., are all large
meat-consumers, while the more or less purely vegetarian races,
such as the Brahmins, are gradually being eliminated as recruiting
sources for the Indian Army. We shall study the influence of
the protein element of the dietaries of these races presently,
simply pointing out now that the elimination of the several
causes advanced by Kellogg, effected by comparison of tribes or
races living under identical conditions as regards sexual excesses,
climate, immature age of marriage, etc., brings out in its proper
aspect the determining influence of diet on the character forma-
tion of a people. All the evidence we have been able to collect
from observations on the different tribes and races of India
points to a high level of protein interchange in the body being
accompanied by a high development of physique and manly
qualities ; whilst under the opposite conditions, poor physique,
and a cringing, effeminate disposition is all that can be expected.

THE HILL-TRIBES OF BENGAL.

We have given in Chapter IV. the dietaries of the more
important and accessible of the tribes inhabiting the lower ranges
of the Himalayas in Bengal. From a dietetic standpoint they
may be divided into two great classes, each with two subclasses :

1. Bhutias.

(1) Tibetan Bhutias and Nepalese Bhutias.

(2) Sikkim Bhutias or Lepchas.

2. Nepalese.

(1) Chuttries — higher classes (Brahmins).

(2) Matwales (Mangar, Janidar).

TROPICAL TRIBES AND RACES 185

These tribes inhabit hills whose height averages 5,000 to
6,000 feet above sea-level. The climate, though not so cold as
that of England, is misty and wet during most of the summer
months, and cold, bracing, and clear in the winter. The contrast
between the Bengali and the people of these hills is very marked.
They appear more like inhabitants of different parts of the
universe, rather than neighbours separated by barely fifty miles
of country. The men, women, and children are jolly, light-
hearted, always laughing, joking, and chatting ; the children
playing, singing skipping as they run about, much in the same
way as children do in England. This is all the very antithesis of
what will be found in Bengal and Orissa. The children in
Bengal are poor, miserable, pot-bellied little creatures, with
little or no joy in their lives, compared with these happy- looking
well-fed children of the hills. The hill people in general are very
healthy, strong, and well- developed, some tribes being of really
fine physique ; they are full of energy, and capable of sustaining
the most arduous labour and prolonged muscular exertion. The
loads that even the women and little children are commonly seen
to carry up the steepest hills are incredible, and could hardly be
believed possible.

So far as the evidence goes, two factors account for the marked
contrast between the Bengali and these hill- tribes — viz., climate
and diet. The other causes advocated by Dr. Kellogg are even
more in evidence, particularly sexual excesses, than in Bengal.
Whilst there is no doubt climate has a great deal to do with the
higher scale of general development and efficiency, that it is not
the only, or even the most important, factor can be shown by a
comparison of the several classes living under practically identical
conditions, but with differences in dietary forming the one out-
standing influence on their respective characteristics. The
following facts were collected :

1. Bhutias (140 men examined),
(a) Tibetan Bhutias.

Height averaged between 5 feet 6 inches and 5 feet 7 inches.
Tallest, 5 feet 9 inches.
Shortest, 5 feet.

Chest girth averaged between 35 and 37 inches.
Greatest, 38 inches.
Smallest, 32 inches.

The development of the neck and calf of the Bhutia is very
marked for their height, an average of between 14 and 15 inches
being obtained from the measurements

186 THE PKOTEIN ELEMENT IN NUTRITION

(6) Sikkim Bhutias, or Lepchas.

Height averaged between 5 feet 4 inches and 5 feet 6 inches.

Tallest, 5 feet 7 inches.

Shortest, 5 feet.
Chest girth, the same as in Tibetan Bhutias. (Pure Lepchas

are slightly smaller in stature than this.)

2. Nepalese (64 men examined).

Height averaged between 5 feet 2 inches and 5 feet 4 inches.
Tallest, 5 feet 6 inches.
Shortest, 4 feet 8 inches.

Chest girth averaged between 32 and 34 inches.
Greatest, 36 inches.
Smallest, 30 inches.

The Tibetan Bhutias are probably the finest specimens of
manhood amongst these hill- tribes. They are stronger physi-
cally and more powerfully developed than the Sikkimese or
Nepalese. Most of the really hard work, such as carrying
dandies, hauling rickshas, etc., is performed by these people.
The women are equally well developed, and are capable of
carrying out the most trying muscular ordeals ; young girls will
readily undertake the transport of the heaviest trunks and
articles of baggage up the very steep paths in Darjeeling and its
precincts. The Bhutia from his earliest years is accustomed to
weight-carrying, the children being loaded with weights they can
just stagger under. As years go on and strength improves,
greater and heavier burdens are carried, until in adult life loads
of 200 pounds and upwards are easily managed. A working
coolie will go steadily on carrying such loads all day, making
trip after trip in a way never met with in Bengal. The constancy
of theBhutia's working capacity is a most noticeable feature when
contrasted with the methods of the Bengal coolie, who, after
even the slightest exertion, must have a rest and, if possible, a
sleep to recover from the consequent exhaustion.

Amongst the hill-tribes themselves the Nepalese and Tibetan
Bhutias are the finest specimens of manhood in every respect ;
next to them come the Sikkim Bhutias, and then the Nepalese.
It will be observed from the data collected that the Nepalese
are considerably smaller in stature than the Bhutias. They are
^also less hardy and less muscular. The Nepalese are usually
to be found as ordinary working coolies or as house servants
— i.e., in situations requiring considerably less expenditure of
energy than in the work performed by Bhutias. These tribes
are all purely Mongoloid in type, there being little or no admixture
of Indo- Aryan or Dravidian elements (Kisley). Their customs

PLATE V

TROPICAL TRIBES AND RACES 187

with regard to marriage, sexual matters, outdoor life, and
exercise, are, so far as we could obtain evidence, practically
identical, and yet within these tribes, derived from the same
stock, living under similar climatic and tribal conditions, marked
differences in physique have developed.

We hold that, while there may be other factors to account for
the superiority of the Tibetan and Nepalese Bhutia, diet and the
high level of protein metabolism he attains have a most important
influence in determining his manly form and energetic dis-
position. We have given details already of the dietaries of the
tribes inhabiting the hills of Bengal, and reference to them will
show that the more nutritive the diet, and the more assimilable
the protein element, the higher the tribe's place physically in the
scale of mankind. From actual work* done on representatives
of these tribes, it was found that the dietaries show a gradual
decline in the amount of nitrogen per kilo of body weight under-
going metabolism, and in accordance with this there is an
accompanying fall in the physique and general efficiency of the
different tribes from Nepalese and Tibetan Bhutias to Sikkim
Bhutias, and lastly to the lower classes of Nepalese.

This can only be explained on the basis of differences in diet ;
the other factors put forward by Kellogg are common to all the
tribes. To anyone who has seen the powerful, muscular dandy-
carriers of Darjeeling, and the much slighter though compactly
built Nepalese, no evidence will be required to bring out the
superior physical development of the former ; and when along
with this we find the Bhutia attaining a much higher level of
protein interchange than the Nepalese, the conclusion that a
close relationship exists between the scale of protein metabolism
and the growth and development of the tissues of the body is
justifiable. The average values of the dietaries of these hill
people was found to be —

1. Tibetan Bhutias, Bhutias from Bhotan (dandy-carriers, ricksha-men,

etc., who do the hardest work) :

Protein, 175 grms., of which over 60 per cent, is derived from animal
source.

2. Sikkim Bhutias (hard-working classes) :

Protein, 131 grms., of which over 70 per cent, is derived from an
animal source.

3. Nepalese Matwali (cultivators, coolies of poorer classes) :

Protein, 110 grms., of which only a small percentage is derived from
an animal source.

* Scientific Memoirs. Government of India, No. 38.

188 THE PROTEIN ELEMENT IN NUTRITION

From a study of the hill- tribes around Darjeeling it is evident
that the well- developed and more muscular races are those whose
diet is very superior in the amount of absorbable protein it
presents. The Bhutia, by far the most capable of these people
in those occupations requiring great muscular exertion, attains a
nitrogenous metabolism much higher than any other tribe. Just
as was the case with the inhabitants of the plains of Bengal,
Behar, and Orissa, so with the races in the hills, variations in the
level of the average nitrogenous metabolism appear to be the
determining factors of the several causes that go to relegate,
fix, and maintain the position of a people, tribe, or race in the
scale of mankind. The daily nitrogenous interchange of these
hill-tribes works out to be —

1. Bhutias : N per Kilo of Body Weight.

Nepalese Bhutias 0-42 grm. (very highly

animal diet).

Tibetan and Bhotan 0-35 grm.

Sikkim Bhutias 0-25 „

2. Nepalese 0-18 to 0-25 grm.

Contrasted with —

3. Beharis and Eastern Bengalis . . . . 0 14 to 0-16 grm.

4. Bengalis and Ooriyas (rice diet largely) . . 0-116 to 0*12 grm.

THE RACES OF THE GANGETIC PLAIN.

Of all factors other than diet that influence the stature and
general physical endowment of the people of India, race or the
particular stock from which the tribes originally sprung is of
first importance.

Risley states that race differences play a larger part in the
distribution of stature in India than is the case in Europe. The
tallest statures are massed in Baluchistan, the Punjab, and
Rajputana, and a progressive decline may be traced down the
Valley of the Ganges.

In discussing the effects of diet as exhibited by the inhabitants
of the Punjab, United Provinces, Behar, and Bengal, it is of
importance to take into account the influence of race, and, by a
comparison of tribes from the same stock, to eliminate this
factor in the same manner as those laid stress on by Kellogg.
This we have done in discussing the people of Bengal, who are all
Mongolo-Dravidian in type — one of the most distinctive types
in India. It occupies the delta of the Ganges and its tributaries,

TROPICAL TRIBES AND RACES 189

from the confines of Behar to the Bay of Bengal, and includes
the bulk of the population of Orissa. In considering the effects
of diet on the hill- tribes of Bengal, we limited the subject to tribes
representing the pure Mongoloid type.

The only other physical types we are interested in at present
are the Indo-Aryan and Aryo-Dravidian.

The Indo-Aryan occupies the Punjab, Rajputana, and
Kashmir, having as its characteristic members the Rajputs,
Khatris, and Jats. This type shows the highest stature recorded
in India, ranging from 174-8 centimetres in the Rajput to
165-8 centimetres in the Arora. Individual measurements of
Rajputs and Jats (Sikhs) rise to well over 6 feet. Within the
Indo- Aryans, socially, " no gulf can be wider than that which
divides the Rajputs of Udaipur and Mewar from the scavenging
Chuhra of the Punjab. Physically the one is cast in much the
same mould as the other, and the difference in mean height
which the serrations disclose is no greater than might easily be
accounted for by the fact that in respect of food, occupation, and
habits of life, the Rajputs have for many generations enjoyed
advantages, telling directly on the development of stature, which
circumstances have denied to the Chuhra. Stature we know to
be peculiarly sensitive to external influences of this kind."*

The Aryo-Dravidian type occupies the valleys of the Ganges
and Jumna, and runs up into the lower levels of the Himalayas
on the north, down to the southern extremity of Behar. The
stature is on a lower scale than in the Indo-Aryan type, ranging
from 166 centimetres in Brahmins to 159 centimetres in the
Mushahar.

Although these physical types are largely limited to the areas
given, it must be clearly understood that they melt into each
other insensibly. The Rajput, for instance, is found in the
Punj-ab, United Provinces, and Behar. From time immemorial
in India a stream of movement has been setting from west to
east, and from north to south — a tendency impelling the higher
types towards the territories occupied by the lower.

As a general statement of fact it may be accepted that there
is a gradual fall in stature, body weight, stamina, and efficiency
from the north-west regions of the Punjab down the Gangetic
Plain to the coast of Bengal ; that this fall is more marked in a
comparison of representatives of the three races inhabiting this

* Risley, " The People of India."

190 THE PROTEIN ELEMENT IN NUTRITION

area — Indo- Aryan, Aryo-Dravidian, and Mongolo-Dravidian —
but even amongst those of the same stock there is the same
tendency to a lower form of physical endowment as the race
is traced down the valleys of the Ganges and Jumna ; that in
accordance with this decline in manly characteristics it is of the
utmost significance that there is an accompanying gradual fall
in the nutritive value of the dietaries, and more especially in
the average level of protein metabolism attained by the people
of the Punjab, United Provinces, Behar, and Bengal.

In the Punjab the foodstuffs in common use are the better-
class cereals, of which wheat is the most important. Besides
these, different varieties of animal food enter largely into the
dietaries of the great mass of the population. In the United
Provinces wheat is not so much in general use, and animal food
is decidedly less frequently consumed as a common article of
diet ; this falling off is continued as we get farther from the
Punjab, until, in Behar, wheat is replaced to a considerable
extent by rice, and in Bengal, rice is almost entirely used to the
exclusion of wheat, except in the eastern districts. At the same
time the animal content of the dietary becomes greatly
diminished.

We shall now take into consideration the data available from
observations on those tribes which supply recruits for the Indian
Army. Accepting that the tribes recruited from are superior in
physique, courage, boldness, and general manly vigour to the
ordinary population, it will be readily admitted that it is of
importance to ascertain the dietaries on which this superiority
has been attained. If, for instance, it was found that some
of our hardiest and best fighting races lived on dietaries of low
protein content, we should have to acknowledge that such a
finding militated strongly against the views we have set forth
on the importance of a high level of protein metabolism ; on the
other hand, if with a high degree of physical development and
martial qualities an accompanying high level of nutrition is
found to be present, other factors being excluded, such a con-
dition may be reasonably claimed as evidence in favour of the
determining influence of diet on the manly characteristics of a,
people.

TROPICAL TRIBES AND RACES 191

Rajputs.

Rajputs may be divided into two classes, Eastern and Western.
The former are chiefly drawn from Cawnpore, Allahabad,
Benares, and Lucknow districts, while the latter and better
physical type of Rajput comes from Agra, Delhi, Rohtak,
Hissar, Nabba, Patiala, and Gurgaon districts. Rajputs are the
modern non-Brahminical and more or less pure-blooded repre-
sentatives of the early Aryan immigrants into India. A great
proportion of the Rajputs of the Punjab have been converted
to Islam, and have therefore lost their distinctive characters as
Rajputs. Some of the best Punjabi Mohammedans of the Indian
Army are derived from converted Rajput tribes.

The two divisions differ somewhat in their caste rules and in
their dietaries, the Western Rajput tending to be more elastic in
his observance of caste obligations, and hence more amenable
to changes of diet when necessary. The farther west a Rajput
is, the less he is under Brahminical influence ; the closer to
Benares, the more priest-ridden, superstitious, and punctilious
is he in regard to his religious customs. All Rajputs will eat
flesh (except that specially forbidden), and do not object to
the flesh of wild boar, though he will have nothing to do
with the domestic pig.

Foodstuffs eaten by Rajputs — 1. Eastern Rajputs. — Wheat and
other cereals, juar, bajra, maize, and millets. Milk prepared
in various ways, clarified butter or ghi. Legumens — gram dal,
arhar, and urid dais. Little meat or animal food is consumed
by the Eastern Rajput.

2. Western Rajputs. — In addition to those enumerated, animal
food enters much more largely into the diet. Goat's-flesh,
mutton, chickens, fish, and eggs are all made use of by the
Western Rajput. Roughly, 75 per cent, of this class partake
of meat regularly.

The dieting of the Western Rajput is therefore decidedly
superior in assimilable protein to that of the Eastern Rajput,
as the effect of even a small amount of animal food daily
makes a considerable difference in the level of nitrogenous
metabolism. It is significant in connection with this that the
Western Rajput is considered so superior in those qualities
essential in a soldier that the eastern branch of the race
supplies a gradually decreasing number of recruits ; some Rajput

192 THE PROTEIN ELEMENT IN NUTRITION

regiments have discontinued accepting members of the eastern
branch entirely.

There is no doubt the Western Rajputs make far better soldiers
than the Eastern. One reason given is that the former are far
more pure-blooded than the latter ; on the other hand, the
differences in diet and in the consumption of animal food by the
two classes is probably a far more important determining factor.
There is abundant evidence of the truth of this statement in the
respective physical conditions of different sects of Rajputs, pure-
blooded or not as the case may be, when living on different
dietaries. Thus the Rajputs of Jessulmer are physically much
inferior to the Rahtore Rajputs of Bikaner and Marwar, although
both are of pure blood ; the difference is due to the fertility of the
soil and the food materials available in the districts mentioned.
Jessulmer is a comparatively poor country, and is incapable of
producing wheat ; bajra, barley, and gram are raised, but the
higher cereals have to be imported. The effect of this is to lower
the average level of nutrition of the population, and with this
is found a lesser degree of physical endowment and a poorer
martial reputation. The soil of Bikaner and Marwar, on the
other hand, is good and fertile, producing wheat, bajra, rice, and
other cereals ; cattle, sheep, goats, elk, deer, etc., are found in
abundance.

The same influence can be traced in those tribes of the Rajput
race that have been converted to Mohammedanism. Thus the
Sials are Rajput Mohammedans, who were converted to Islam
in the fourteenth century. They are a fine type of men, brave,
self-respecting, and hardy, with considerable pride of race.
Physically they are big and strong, rather rude and rough in their
manners. They are pastoral by instinct, but also engage in
agriculture.

The Tiwanas, Gondals, Chibbs, Kharrals, Bhattis, are all of
Rajput stock. These tribes offer splendid material for those
regiments that enlist Punjabi Mohammedans.

The Rajputs of the eastern portion of the United Provinces
and of Behar illustrate markedly the influence of diet. Priestly
influence from proximity to Benares and a decrease in the amount
of animal protein, accompanied in Behar by a substitution of a
considerable amount of rice for the wheat of the diet, are the
causes that explain the lowered standard of physique, and the
loss of that pride of blood and race, and decrease in that spirit

TROPICAL TRIBES AND RACES 193

of self-reliance which so largely constitutes the martial instinct.
The Rajputs of Oudh are being gradually dropped as a race for
the supply of recruits, while the Rajputs of Behar have long since
been rejected as unsuitable.

Physical Development. — Generally speaking, the physique of
the Rajput is good. The Western Rajput is tall, well-made, with
a good development of muscle, but somewhat light in bone. He
delights in deeds displaying strength and courage, and is the most
manly of all Hindu races. The following are the averages supplied
by regimental medical officers for the physical development :

Height . . . . . . . . .. 67 to 68 inches.

Chest girth 34 to 37'5 inches.

Weight 147 to 154 Ibs.

The Eastern Rajput is not nearly so well developed ; the
average height is less, and the body weight rarely exceeds an
average of 120 to 125 pounds.

Dogras.

The Dogras are a Rajput race of Highlanders, preponderatingly
Hindu by religion. Their country is most fertile, yielding large
quantities of the various cereals and fruits. The hills abound in
cattle of good breed, and agriculture is carried on with intelligence
and care, producing large crops.

The following information is derived almost entirely from
official handbooks on the Dogras, published for the guidance of
recruiting officers in the selection of good fighting material.
Written from an entirely different standpoint to that of this
volume, it is of great interest to examine the views expressed
by the authors* on the effects of diet :

The dawn of Indian history discloses two races struggling for
the soil. One was a fair-complexioned Sanskrit-speaking people
of Aryan lineage ; the other a dark-skinned race of lower type,
the original inhabitants of the land. The earliest records of the
Aryans are contained in the Vedas, a series of hymns composed
in the Sanskrit language from the tenth to fifth century B.C.

As the Aryan colonist spread, subduing the aboriginal tribes,
there gradually arose four classes :

1. A class of priests — Brahmins — who looked after religious
teaching and duties connected therewith.

* Colonel Bingley, Major Longden, Bonarjee.

13

194 THE PROTEIN ELEMENT IN NUTRITION

2. As the simple life became more complex, a class came into
existence who, relieved of the burden of agriculture, attended on
the Maharaja ; this warrior class was called Kshatriyas, and
eventually Rajputs.

3. A class of agriculturists, traders, mechanics, etc., became
differentiated off. These were called Vaisiya.

4. Lastly, the Sudra, or menial class, was composed of
aborigines, and the progeny of marriages between Aryans and
inferior castes, all of whom were excluded from the higher
classes.

In course of time these occupational distinctions developed
into separate castes, and as intermarriage became first of all
restricted, and afterwards prohibited, each caste devoted itself
more strictly to its own hereditary employment.

Prior to the Mohammedan conquest, the whole of Northern
India was ruled by Rajput Princes. Some of these were driven
into the hills and upper valleys of the Chenab, Ravi, and Sutlej .
These hill Rajputs form at the present time the Dogras. They
have been in these regions for over 1,500 years, have been largely
untouched by Islam, and have retained their religion and caste
rules almost unsullied during all these ages.

At the present time the highest class of Dogras are the Mians,
who must never touch a plough. In earlier and troubled times
this vow was easily adhered to, as the Mians were able to enjoy,
either as a right or by force, the fruits of the labour of the
shepherd and ploughman. In peaceful times this was no longer
possible, and large numbers were compelled to take to agri-
culture. The Mians are those who have kept their blood un-
sullied, and their hands from the plough.

The Mians and higher classes of Rajputs, with the exception,
perhaps, of the Jews, of all races in the world, are of the most
ancient lineage and of purest descent. Though now nearly all
agriculturists, Dogras form a military aristocracy of a feudal
type. They are brave, chivalrous, keenly sensitive to an affront,
and specially jealous of the honour of their women.

In disposition they are manly, simple, and honest, and, with
the exception perhaps of the Dogra Brahmins, are little given
to intrigue. The chief characteristic o± the higher classes is
pride of blood. It is among the Dogra Mians and Rajputs that
we find the best specimens of Hindu character. We acquire a
clearer conception of their high spirit when roused, their enthusi-

TROPICAL TRIBES AND RACES 195

astic courage and generous self-devotion, so singularly combined
with gentleness and an almost childish simplicity of character.
In no part of the world has the devotion of soldiers to their
immediate chiefs been more remarkable than among the Dogras.
They have ever been distinguished for their military fidelity and
loyalty.

In vigour and manly strength the Dogra is not the equal of the
Sikh or Jat. In their own country the Mians and Rajputs are
generally inclined to be delicate. This is due partly to poverty
and under-feeding from their dislike to agriculture, and partly to
the prevalence of fever. When enlisted, however, they rapidly
develop and fill out ; but though good food, combined with drill
and gymnastics, make them steady and well set-up, they rarely
run to any great height, their average stature being 5J feet.
The taller men amongst them are chiefly agriculturists from the
plains, who, though physically more stalwart, have not the
pluck and activity of the hardy hillmen.

Since the British occupation of Kangra, the Dogras of that
neighbourhood have been compelled by poverty to resort to
agriculture, though the highest classes still hold aloof from
ploughing.

At the present time fully 70 per cent, of the population are
agriculturists. In Jummoo, on the other hand, the predomin-
ance of the cultivator is less striking ; here the Mians live in
pride, poverty, and indolence. This acts unfavourably on their
physique, which cannot be compared with that of the better-
fed agriculturists of Kangra. Opinions differ as to the relative
value of Jummoo and Kangra Dogras as soldiers. Both are
equally courageous, but the Kangra Dogras are generally
esteemed to' be the better. They are said to have more
heart, greater capacity for endurance, and greater pride of race.

The agricultural classes have usually three meals a day.
Before going to work the men partake of bread reserved from
the previous night's supper. At noon is eaten the first full
meal, consisting of rice, dal, and bread made of wheat or maize.
Supper mainly consists of wheat bread, rice seldom appearing.
The different millets are largely used as food. Maize is a very
favourite grain, and from September to May is in constant
consumption. After May wheat matures, and for the
remaining six months of the year wheat meal is the staple
foodstuff.

196 THE PROTEIN ELEMENT IN NUTRITION

Milk, curds, buttermilk, whey, and other preparations form
a very important element of their dietary. In the agricultural
districts milk and milky foods are cheap and easily procured ;
the effect is that the Jats, Sikhs, and agricultural Dogras consume
large quantities, raising very materially the protein and nutritive
value of their dietaries.

Meat is a luxury with the bulk of the people ; they prefer
goat to sheep. In most parts there is a good supply of fish,
which generally forms a large constituent of their diet.

The strictest sects do not, but many Dogras do, eat fowls
and eggs. Being keen sportsmen, they supplement the animal
protein of their dietary with the flesh of different kinds of game.

As the great majority of Dogras are Siva and Devi worshippers,
they are allowed to eat meat, a privilege denied to the worshippers
of Vishnu.

In social and religious customs and practices the Dogras are
very much like other Hindu communities, except that they are
more superstitious and priest-ridden than the men of the plains.
Infant marriages are customary, the only exception being in the
case of the highest caste girls, for whom it is difficult to find
suitable husbands.

We shall now give a few extracts bearing on the effects of diet
as exemplified in the different Dogra sects.

Tho Dogra Brahmin. — In appearance the cultivating Kajput
Brahmin can hardly be distinguished from Rajputs, except
that their physique is generally superior, the result probably of
the better nourishment they get. They make good soldiers
despite their prejudices and indolence. The average standard of
physique among them is good, and they are superior physically
to the Rajput Dogra, as the Brahmin contrives to get more of
the loaves and fishes of life than his co-religionist. They are
notoriously given to intrigue, and are not really military by
instinct, so that there is no great demand for them as soldiers.

Dogra Rajputs — 1 . Mian Rajputs. — This class maintains a most
inveterate prejudice against touching the plough and against
agricultural pursuits.

The adoption of agriculture makes a great difference in the
physique of the Dogra Rajput. With more and better food
he becomes more robust, and his muscles become more fully
developed. The Mians, who still keep up their prejudices, are
often thin and weakly looking, though a few months of good

TROPICAL TRIBES AND RACES 197

food and steady drill will work a wonderful change in their
appearance.

2. The Rana and Thakur classes of Dogra Rajputs, with whom
Mians intermarry, consist chiefly of the descendants of Rajput
families which from time immemorial have been agriculturists.
These classes are par excellence the most soldierly of all Dogras,
and are of fine physique.

3. Rajputs of the Plains. — The Rajputs of the plains have lost
the high-bred looks of their hill brethren. This is due to the
fact that they have for centuries followed the plough. But
agriculture, though unfavourable to their good looks, has proved
decidedly beneficial to their physique, and these Rajputs of the
plains are generally more muscular than the true Dogras of the
hills. They are not quite so smart on their feet as the latter,
but they nevertheless make good soldiers, and are generally
very expert wrestlers.

4. Lower Classes of Dogras. — These are Rajput, by origin, but
have lost their social position. They are excellent agriculturists,
steady, industrious, and plodding. Hence they are far better
off than the Mians. They are of better physique, and have
more robust constitutions than the higher Rajputs, but are not
so refined. In military qualities they differ but little from
Rajputs, with whom they are mixed up indiscriminately in all
Dogra companies.

A good deal of valuable information on the influence of food
is afforded by the above extracts from handbooks written by
officers who have had long and close relationship with the classes
discussed. The most important findings from our standpoint are
the changes that have taken place in the physique and stamina
of the Mian Dogras during the last century, despite their pure
extraction from Rajput Princes, and despite the benefits of a
hilly climate ; the Rajput Dogras of the plains, and even the
lower classes of Dogras of mixed extraction, on the other hand,
exhibit in a marked manner the beneficial effects of good food
on the virility and general efficiency of the individuals of the
race. This influence is all the more in evidence when it is
remembered that the great majority of these agriculturists and
peasant farmers inhabit the plains and lower valleys of the
submontane regions, where climatic conditions are not so favour-
able as in the hills, and where malaria is exceedingly prevalent.
Despite these disadvantages, the well-fed agriculturist, both of

198 THE PROTEIN ELEMENT IN NUTRITION

the hills and the plains, has maintained his physique, the develop-
ment of the lower classes of mixed descent improving under the
favouring influence of good food to be equal to that of the pure-
blooded cultivator ; whilst the higher Mian Dogras, with climatic
conditions and descent in their favour, but living on poorer
dietaries, have within the last century gradually descended to a
lower level of physical endowment, accompanied by a decrease
in stamina, endurance, and resistance to disease. The Mians are
the representatives of the great warrior class, Kshatriyas, who,
in the times prior to British occupation, were accustomed to
live on the fat of the land, and levied toll on all and sundry.
For years they provided the very best material for the Indian
regiments ; now the peasants and even lower-class agriculturists
are more and more largely recruited from ; the Mians, owing to
a lack of physique, being selected in gradually diminishing
numbers.

Of the Dogras as soldiers, it has been said that they are not
remarkable for daring or impetuous bravery, but they can
always be depended on for quiet, unflinching courage, patient
endurance of fatigue, and orderly obedient habits. They have
not the grit and " go " of the better classes of Sikh, Pa than, and
Gurkha ; their soldierly qualities are essentially more solid than
brilliant. Their steady, resolute courage makes them reliable,
and they justly enjoy the reputation of being amongst the best
fighting material in the Indian Army.

In physique they are not tall and muscular men, like the
Pathan and Sikh, nor have they the physical vigour and sturdi-
ness of the Gurkha. They are somewhat slightly built, of average
height, with refined and finely cut features, fair complexions,
and well-proportioned figures. Dogra recruits, however, caught
young, while there is yet time for their physical development to
take place, soon fill out with liberal feeding, drill, and systematic
exercises. The general appearance of a Dogra regiment leaves
nothing to be desired. The following data concerning Dogras
has been supplied from a Dogra regiment :

FOODSTUFFS CONSUMED (AVERAGE PER MAN DAILY).

Protein Value.

Wheat .. . 12 to 16 ozs.'
Rice

Dal

f!20 to 135 grms., of which 40 per
cent, is derived from an animal
SOUrCe'
Vegetables

TROPICAL TRIBES AND RACES 199

The Dogra recruit, therefore, is provided with a very sub-
stantial daily ration, with very gratifying results so far as his
muscular and physical development is concerned.

Average weight of recruits after six months' service . . 130 Ibs.
,, chest girth of recruits after six months' service 33 £ to 36 in.
,, height of recruits after six months' service . . 5ft. 6 in. to 5ft. Sin.

The chest girth increases on an average | inch during the first
six months in military employ — measurement taking at the end
of complete expiration and arms extended above the head.

Jats.

The Jats also belong to the Indo-Aryan physical type, and are
derived largely from the same stock as the Kajputs and Dogras.
Some authorities hold, however, that the Jats are of Scythian
origin. Jats are divided into eastern and western. The eastern
Jats inhabit the eastern districts of the Punjab and United
Provinces. As a rule, only Hindus of eastern divisions are en-
listed for Jat regiments. They are mainly agriculturists, and
make most excellent farmers, rarely equal and never surpassed
by any class of peasantry in India for industry and skill.

The foodstuffs made use of in their own homes during the
important early years of life when growth is taking place are —

Bread made from wheat, juar, and other cereals.

Rabri, prepared by mixing bajra with buttermilk.

Dais and vegetables of all kinds. Rice is seldom eaten.

Milk, curds, butter, and other preparations of milk are used
to a considerable extent, as the majority of families from which
recruits would be obtained are able to keep their own cows and
buffaloes.-

Animal food enters to a very limited extent into the diet of
the Jats in their own homes. Mutton, goat's flesh, and eggs are
partaken of very sparingly — on an average once or twice a
month. The protein element of the diet is considerably aug-
mented by the large quantities of milk consumed even by adults.

These eastern Jats are of very fair physique, and their soldierly
qualities are undoubtedly great ; and though not so sturdy as
some of the other races of the Punjab, their claim to be regarded
as good fighting material is valid.*

The western Jats have largely taken to Mohammedanism and

* Bonarjee. " The Fighting Races of India."

200 THE PEOTEIN ELEMENT IN NUTRITION

Sikhism. The better classes of Sikhs are drawn from the Jat
and Khattris, the finest specimens being Jat Sikhs, who possess
all the virtues of the Jat of the Punjab, and many also developed
by Sikhism.

Those Jats who have changed from the Hindu faith to Islamism
and Sikhism have at the same time adopted the dietetic customs
of their new religion. Animal food, therefore, enters much more
largely into their dietaries than is the case with the eastern
Jat. Large numbers of Islam converts are enlisted as Punjabi
Mohammedans, as, for instance, the Kharral tribe, who are
hardy, well-built, and good-looking, possessing the martial
instinct to a high degree, and make very good soldiers.

The Jat Sikh is an exceptionally fine type of Asiatic,
exhibiting a splendid physique, well-proportioned, and solidly
built. With his manly and handsome features, his sturdy
independence, self-respect, and racial pride, he is the beau ideal
of an Oriental soldier. The Khalsa Sikh, or Sikh par excellence,
is drawn from many castes, but mostly from the Punjab Jat,
to whose sturdy and independent character the warlike and
manly precepts of Sikhism appeal. The Jat Sikh is the truest
and best embodiment of Sikhism. Jats who have adopted other
religions and have not entered the fold of Khalsa, do not make
nearly so good soldiers as their brothers who have taken this
step.*

The dietaries of those Jat tribes who have become Moham-
medans and Sikhs are considerably superior in the degree of
protein metabolism they permit to those of the eastern Hindu
Jats. Mohammedans in general are meat-eaters, consuming the
flesh of the ordinary animals used for food in European countries,
with the exception of the pig. Punjabi Mohammedans live
largely on wheat, millets, maize, peas, milk in its various forms,
and animal materials.

The Jat Sikh also has not attained his high position as regards
physique and soldierly qualities on a diet poor in protein. Like
Jats everywhere, whatever religious views they may hold, they
are splendid farmers. A very large proportion are peasant
proprietors, which condition insures a full sufficiency of all food-
stuffs available from the land. Wheat is their staple food, but
bajra, maize, and juar are also eaten during certain seasons of the
year. Milk, curd, buttermilk, and butter are largely consumed.

* Bonarjee, " The Fighting Races of India."

TROPICAL TRIBES AND RACES 201

Goat's flesh, venison, mutton, pork, game of all sorts — in fact,
all animal food except beef, which is forbidden. Eggs and fish
are also eaten when procurable.

The following diet gives a fair average for the daily consumption
of food by the Jat Sikh. The information was obtained from
native officers of a Sikh regiment.

Protein Value.

Wheat . . . . 24 to 26 ozs.)

Dais . . . . 2 ,, 130 to 151 grms., of which over

Vegetables .. 4 ,, [r 40 per cent, is derived from an

Milk . . . . 16 ,, animal source.

Meat . . . . 6 to 8 „ /

When rice or millets, maize or barley, are made use of, they
replace about an equal quantity of wheat ; but when this is the
case, usually considerably more milk is consumed. The Jats
use curdled milk very largely, and buttermilk is a staple article
of diet in every family.

The average dietary as outlined above is of a superior
type, and would mean a high level of protein interchange.
Accepting the average protein absorption to be 80 per cent., it
would mean a metabolism of from 18 to 20 grammes of nitrogen
daily.

Physical Development. — Jat Sikhs as a class are late of develop-
ment ; recruits of eighteen or nineteen years of age are often
lanky, undeveloped-looking lads. As a rule they have well-
shaped chests, with good expansion, and have plenty of " bone."
They rapidly develop into men of powerful physique under a
course of drill, gymnastics, etc., with a liberal diet.

Average height . . . . . . .. 68 to 69 inches.

• ,, chest girth 33 to 35 „

weight 140 to 150 Ibs.

It is evident from the information collected on the influence of
food on these different classes of Jats that the evidence bears
out in every detail the conclusions arrived at from a similar
analysis of the conditions prevailing in the several classes of
Rajputs and Dogras. Contrasting tribes or sects derived frcm
the same stock, living under identical conditions and customs,
but under different dietetic standards, we are able to obtain
corroboration of the views generally held by physiologists with
regard to the important role played by protein in the nutrition
of mankind, and the determining influence of a high level of

202 THE PROTEIN ELEMENT IN NUTRITION

nitrogenous interchange on the physique, stamina, and manly
characteristics of the individuals of the races.

The facts collected and published for the guidance of recruit-
ing officers show undoubtedly that those classes that are in a
position to obtain a liberal supply of good food form the chief
sources of the best fighting material, while the less well-fed
classes, even though in some cases everything except diet is in
their favour, are acknowledged to be inferior from a military
standpoint in the necessary qualities of the soldier. We have
brought forward abundant evidence on these points in con-
sidering the eastern and western Rajputs ; the different classes of
Dogras, particularly when discussing the effects of food on the
Mians and on the lower agricultural classes, who, despite their
mixed Aryan and Dravidian blood, have gradually developed into
material superior in physique and stamina to the pure-blooded
descendant of the old warrior stock of Rajputs ; and, lastly, the
effects as exhibited by the several sects of Jats, Punjabi Moham-
medans, and Jat Sikhs, in each and all of whom the merits and
demerits of dietaries high and low in protein respectively are very
apparent and easily estimated. The evidence afforded by a study
of the influence of diet on these races is entirely at variance with
the views expressed by Chittenden, and can only lead to one
conclusion — viz., that a sufficiently liberal degree of nitrogenous
interchange is essential for the formation and development of
those attributes and qualities of mind and body that are
alike the pride of the soldier and the envy of inferior races.

The Sikh.

" Hardy, brave, intelligent ; too slow to understand when he
is beaten ; obedient to discipline ; attached to his officers ;
careless of caste prohibitions — he is unsurpassed as a soldier
of the East, and takes first place as a thoroughly reliable useful
soldier. The Sikh is always the same, ever genial, good-
tempered, and uncomplaining ; as steady under fire as he is
eager for a charge. When well and sufficiently led, he is the
equal of any troops in the world, and superior to any with
whom he is likely to come into contact " (Falcon).

" As a soldier the Sikh displays a cool, quiet, and resolute
courage, and is much less likely to lose his head in the excite-
ment of battle than the Pa than. His passions are well under

TROPICAL TRIBES AND RACES 203

control ; he knows how to keep cool and unexcited in moments of
difficulty and danger. He is therefore much less liable to sudden
panic than the Pa than, though he may not have the same dash and
elan as the Pa than in his most warlike mood. Taken as a whole,
the Sikh is one of the finest types of men to be found in Asia.
Is independent without being insolent, resolute and firm in
character, remarkably free from petty bias and prejudices which
run rampant in a land of prejudices like India. Respects himself,
and as a result commands the respect of others ; is a soldier by
instinct and tradition ; regards cowardice as worse than a crime ;
and with his splendid physique and well-bred ways is one of the
finest of Oriental races " (Bonarjee).

Unlike the Rajputs, Dogras, or Jats, Sikhs are not the high
caste descendants of the conquering Aryans. Sikhism includes
within its folds all of these, but in addition many of the lower and
despised classes. Thus the despised scavenging Chuhra of the
Punjab, Sikhipm has transformed into the soldierly Mazhabi.

The earlier Gurus of the Sikhs preached a peaceful religious
life, and it was only the pressure of Mogul dominance that first
turned Sikhism to thoughts of war. Har Govind, a practical and
adventurous Guru, urged the necessity for a knowledge of the
use of arms.

He not only permitted, but encouraged the use of flesh — except
that of cows and unclean animals — as articles of diet, believing
its consumption would tend to improve the strength and physique
of the race. He did his utmost to instil manliness, self-reliance,
and courage amongst his followers. The absence of caste drew
large numbers to the Sikh fold, and many of the lower castes, but
also of the higher, as Jats, Khattris, and Rajputs, embraced the
Sikh faith.

After centuries of warfare and gradual consolidation, the Sikh,
became united under Ranjit Singh, and overran the whole of the
Punjab.

In Chapter IV. we have given the food materials and dietary
of the Sikh in detail, and shown that, as in the case of the Jat
Sikh, his splendid reputation and martial qualities have not been
acquired on dietaries affording a low level of protein metabolism ;
but, on the contrary, that the nitrogenous interchange possible
from his diet scales is quite on a par with that of European
soldiers.

The Sikh is a high protein-feeder ; he will eat the flesh of all

204 THE PROTEIN ELEMENT IN NUTRITION

the ordinary animals used as food, except the cow and buffalo.
Milk in all its different preparations is very largely consumed —
even the soldiers, who have to buy it out of their pay, drink up
to 2 or 3 pints daily.

In connection with this the following extract from a letter
written by the Adjutant of a Punjab regiment may be quoted :
" As to the effects of good food, I may mention that since the
regiment left Calcutta, where milk was expensive and of poor
quality, and arrived in Dera Ismail Khan, where milk is cheap
and good, the men have improved in health and general fitness
to a great extent. As milk is the staple article of diet of the
Sikh, you can easily understand that when he comes into such
favourable circumstances his improvement is noticeable.'"

It is of interest to note that the Sikhs, like most Hindu tribes,
marry their female children before the first menstrual period.
It would not, therefore, appear that this custom has so dele-
terious an influence on physique as is generally thought. Infant
marriage is dying out to some extent amongst the Sikhs and
some other Hindu tribes.

A general idea of the physical development of the young Sikh
recruit will be obtained from the following data :

Average age . . . . . . 18 years.

height . . . . . . . . 67^ inches.

chest girth . . . . . . 33£ to 35 £ inches.

weight 135 to 140 Ibs.

Taking the dietaries as recorded in Chapter IV., Study No. 7,
and the facts given under Jat Sikhs, it may be accepted that the
nitrogen metabolism of the Sikh averages from 18 to 20 grammes
daily. This, for an average weight of 70 kilos, would mean
the metabolism of 0-25 to 0-28 gramme of nitrogen per kilo of
body weight, or more than twice the amount Chittenden and
the advocates of a low protein dietary consider necessary. The
Sikh is perhaps the best known of the martial tribes of the plains
of India ; it is therefore of interest to learn something of the
dietary on which he lives. The evidence shows that, although
Sikhism is composed of representatives of many different castes,
some of high standing such as Rajputs, Jats, etc., and some of
the despised lower classes of impure descent, such as the Chuhra
and Sudra, the effect of the religious and military precepts,
combined with a liberal dietary, has been to increase the physique,
stamina, and soldierly qualities of those derived from the higher

PLATE I

TROPICAL TRIBES AND RACES 205

castes, and inculcate the martial spirit into those of obscure
origin. The protein metabolism of the Sikh is superior to that
of the other fighting tribes so far considered, and, failing any
other explanation of his superior qualities, we must admit
the undoubted influence of his highly nitrogenous dietary during
the important early years of life — the period during which the
body framework and protoplasmic tissues are being built up.

We may conclude this study of the Indo-Aryan physical type by
saying that where it is possible to eliminate climatic, social, and
caste influences, as in a comparison of tribes living under the
same conditions, except as regards diet, there can be no doubt
of the superiority, physically, morally, and socially, of those
whose diet is the most liberal, and whose daily average of
metabolized nitrogen reaches a high level. Having studied the
effects of dietaries offering varying quantities of assimilable
protein on different tribes, otherwise under similar conditions,
we are more firmly than ever of the opinion that the level of protein
exchange advocated by Chittenden is too low, and that a supply
at least equal to that of the usually accepted standards is to
the advantage of the individual and to the welfare of the race.

The Pathan.

The Pathans are given by Kisley under the Turko-Iranian
physical type. The Pathan himself claims to be of Jewish origin.

The different tribes are pastoral and agricultural ; they possess
large flocks of sheep, goats, cows, etc. Milk is highly esteemed,
and the better classes live exceedingly well on a highly protein
dietary of wheat, maize, milk in various forms, and large quan-
tities of animal food. In their homes animal food is eaten daily.

They have never been accustomed to law nor settled govern-
ment, and are a wild, lawless, turbulent people, to whom law and
order are things to be scoffed at. Pathans are pre-eminently
resolute and self-reliant. As a soldier he displays great dash and
elan, but is apt to be carried away in the heat of battle. He
takes a just and manly pride in himself, and considers himself
superior to other races. His resolute look, upright gait, tall and
muscular frame, and firm step betoken many of the qualities of
the genuine man.

The Pathan is superior in physique to any of the races men-
t'oned. As, in addition to their superior type of dietary, the

206 THE PROTEIN ELEMENT IN NUTRITION

Pathan tribes come from a different stock and live mainly in
the hills, we cannot make use of them in a comparison with the
Rajputs, Jats, or Sikhs.

It is sufficient to point out that their splendid physique and
fighting qualities have not been attained on diets permitting a
low level of nitrogenous metabolism.

We may conclude this study of the effects of the level of
protein metabolism on the physique and general efficiency of
different tropical tribes and races by stating that the facts,
as set forth in the preceding pages, afford ample proof of the
all-important influence exerted by food, and particularly protein,
in determining the degree of muscular development, the general
physical endowment, the powers of endurance, resistance to
disease, and, most important of all, the place a tribe or race
has won for itself in manliness, courage, and soldierly instincts.
We have no hesitation in saying that, amongst the tribes and
races contrasted, the higher the level of protein interchange,
the more robust and energetic, and the more manly the race.

From a practical standpoint under natural conditions, in
contrast to laboratory results obtained under artificial con-
ditions, it appears somewhat superfluous to have to insist on
this point, and support what should be a foregone conclusion
with a mass of evidence. But with such an eloquent appeal
as that made by Chittenden for a decrease of at least 50 per
cent, in the ordinary protein standard, backed up as it is by
an array of such seemingly convincing arguments, it is only
meet that the real facts should be brought to light before
harmful measures in the feeding of large bodies of men have
been adopted.

We might illustrate further the determining influences of a
liberal supply of protein by a study of other races and tribes
in India. Thus there are the Afridis, physically a fine type, tall,
muscular, hardy, brave, proud, and self-reliant. They make ideal
soldiers. The Waziris, a tribe probably of Rajput origin, who have
acquired a great reputation for courage and warlike qualities.
The Bajouris, physically a grand race of men, are hardy, muscular,
and brave, and make good soldiers. The Baluchis are manly,
frank, and strong, inured to hardships and exposure. They are
a fine type of men, and have acquired a reputation for truth and
fidelity. Many other sects and tribes of the Indian frontier

TROPICAL TRIBES AND RACES 207

might be made use of to show that wherever the characteristics
and instincts of the soldier are to be found, there will also
be present a high level of protein interchange. The different
classes just mentioned are all large meat-consuming people.
They are mostly pastoral, and all possess large flocks and
herds. They live mainly on wheat, maize, barley, rice, milk,
and animal flesh. Their country is, however, very sterile, so
that the products of agriculture form a comparatively small
part of the daily food.

The photographs of typical representatives of the several
sects and tribes discussed will give a fair idea of the differences
in physique met with amongst the inhabitants of India.

The evidence of the importance of a high level of protein
metabolism is overwhelming, whatever the standpoint from
which its effects be examined. Considerations of space do not
permit us to do more than call attention to two important
investigations carried out on this interesting subject. The first
was the series of experiments with batches of soldiers to
determine the food requirements for sustenance and work.
The results furnished by the Committee on the " Physiological
Effects of Food, Training, and Clothing on the Soldier " show
that when hard marching is performed a high protein dietary
is an absolute necessity.

Over periods of a fortnight of hard training the protein element
was increased up to well over 200 grammes per man daily. The
Committee state that these figures were undoubtedly high, but
there was no evidence that they were too high.

The conclusion of the medical officers who took part in both
experimental periods — with a low and high protein content of
the diets — was that the best ration for service is one containing
about 200 grammes of protein.

Lieutenant-Colonel Melville,* R.A.M.C., speaking of the results
obtained during the first experimental period, states that 190
grammes of protein appeared to be ample, whilst 145 grammes
was too low.

The second important series of experiments to which we wish
to call attention will be found in the Philippine Journal of Science
of February, 1911.

After a most exhaustive and brilliantly successful series of

* Melville, " Food Requirements for Sustenance and Work," British Medical
Journal, October, 1910.

208 THE PROTEIN ELEMENT IN NUTRITION

investigations to determine the influence of a restricted diet on
growing dogs, Aron arrives at the following conclusions :

A growing animal which receives only sufficient food to keep
its body weight constant, or to allow a slight increase, is in a
condition of severe starvation.

If by a restriction of food the increase in weight is inhibited,
the skeleton grows at the expense of other parts of the body,
especially of the flesh.

Most of the organs retain their weight and size, while the brain
grows to reach its normal weight.

The composition of the body, when at a constant weight,
undergoes remarkable changes : fat is consumed more or less
entirely, the quantity of protein, especially of the muscles, but
not of the organs, is diminished, and a great proportion of the
body tissues is replaced by water ; thus this water and the
increase of the skeleton together replace the body material lost.

The caloric value of 1 gramme body weight of an animal
which has undergone such a process to its extreme limit may
amount to only one-third of the normal value.

It is possible by supplying suitable amounts of food to maintain
a dog in an emaciated condition, apparently in good health, and
at the weight of a puppy, for nearly one year, while its weight
at the end of the year should be three times as great. If such
an animal is thereupon fed amply, it fattens and rounds out,
but does not reach the size of a control animal which from the
beginning has been normally fed. It is unable to make good
the growth suspended by the long restriction of food.

It will be readily recognized how very closely Aron's results
correspond to those obtained with dietaries poor in protein, as
exemplified by the rice-eating Bengali and Ooriya. Aron
experimented with dietaries deficient in energy and in all the
different elements. The Bengali and Ooriya show that very
similar effects are produced when — the potential energy and
carbonaceous material of the diet being abundant — the protein
element alone is deficient.

THE INFLUENCE OF CERTAIN SUBSTANCES PRESENT IN THE FOOD
IN MINUTE QUANTITIES ON THE MAINTENANCE OF NUTRITION.

Keference has already been made to the fact that recent lines
of research point to the presence of certain substances in the
food, present only in minute quantities, as being essential for

TROPICAL TRIBES AND RACES 209

the nutrition of the organism. Hill and Flack, in their work on
the nutritive value of flours, have shown that foodstuffs must
be regarded, not only from the standpoint of their protein con-
tent and caloric value, but also from another aspect — viz., the
presence or absence of certain organic constituents which have
been found to be of the very greatest importance in the growth
and nutrition of the body. The researches of Funk* and others
on the isolation of the substance contained in the polishings of
rice, absence of which from the food is now generally recognized
as the specific cause of beri-beri in man and polyneuritis in
animals, is another example of certain materials present in the
food whose importance is out of all proportion to their nitrogen
content or caloric value.

It is now generally admitted that the body requires for the
growth and repair of its protoplasmic tissues certain complexes
or grouping of nitrogenous combinations, and that, failing a
sufficient supply of these, neither growth nor nitrogenous equi-
librium can be maintained, no matter how much protein may be
offered in the diet. We have referred to the work done from
this point of view in the first chapter of this volume. It would
appear very probable that certain of these groups or combinations
are provided in the organic base that Funk has isolated from
rice polishings, and that Mooref and his co-workers have shown
to be present in yeast. Such important substances would appear
to be present in many other food materials in their natural
state, but may be lost by certain methods of preparations — as,
for instance, overmilling of cereals.

Recognizing the important bearing of these discoveries on
the problems' of nutrition and on the maintenance of the body
in nitrogenous equilibrium, it appeared to us to be a matter of
some moment to make certain that the poor physique of the
Bengali was not to be attributed to the absence or insufficient
supply of these essential materials in his food.

A priori the weight of evidence is strongly against such a
contention or such an explanation of the poor muscular develop-
ment of the Bengali. Thus, there is practically no beri-beri in
Bengal, as country rice, and not the highly polished Rangoon
variety, is the form in general use. Further, the fact that large
quantities of dal — a substance very rich in the element lacking

* Funk, The Journal of State Medicine, June, 1912.

t Moore and others, The Bio-Chemical Journal, July, 1912.

14

210 THE PROTEIN ELEMENT IN NUTRITION

in polished rice — are eaten with rice insures that an abundance
of the antineurotic vitamine is provided in the food.

However, to make certain that these deductions were sound,
a series of investigations were undertaken to determine what,
if any, of the Bengal foodstuffs caused polyneuritis in animals,
and what, if any, cured the condition.

Batches of pigeons have been fed on the different Bengal food
materials for over eight months. We have nothing new to
report. Shortly, the results so far in the investigations have
been :

1. No Bengal foodstuff causes polyneuritis in pigeons.

2. Polished rice invariably causes the condition.

3. None of the dais in use in Bengal produce the disease.

4. Indian or country rice has no deleterious effect.

5. Polyneuritis produced by feeding on Rangoon rice is cured
— (a) by feeding with Indian or country rice ; (6) by feeding
with alcoholic extract of rice polishings or of Indian rice ; (c) by
feeding with dais or the alcoholic extracts of dais.

It is evident, therefore, that the absence of the beri-beri
vitamine in their dietary is not the explanation of the poor
physique of the Bengalis.

Further, while there can be no doubt of the importance of these
substances in growth and nutrition, the fact of the necessity of
such bodies in the food is a strong argument in favour of a liberal
supply of food, in order that the system may be afforded the
opportunity of picking out those particular combinations which
are so essential to its nutrition, and is no argument for the re-
duction of either the protein content or total potential value of
dietaries below the generally accepted standards.

These bodies are probably of a specific nature, fulfilling
certain specific functions that cannot be performed by the ordi-
nary cleavage products of protein digestion ; but to believe, as
some are inclined to do, that, because these substances have
been found to be absolutely essential, therefore the protein
element of the diet can be cut down to one-half or one-third
of Voit's standard is to go beyond the indications warranted by
the facts.

It is far more rational to believe that these vitamines are
necessary in addition to the ordinary amino-acids, and that, in
all probability, they can neither take the place of, nor be replaced
by, the products of the tryptic digestion of proteins.

INDEX

ABDERHALDEN, experiments on horse,
8

Aboriginal tribes, 24, 28, 89

Absorbability of foods, 33; Hutch-
ison's table of, 34 ; Langworthy's
groups, 35

Absorbability : of fruits, Jaffa, 35 ; of
protein of rice, 38 ; of tropical food-
stuffs, 36

Absorption of constituents of differ-
ent breads, 50

Absorption of protein: arhardal, 66; of
bajra, 55 ; of barley, 55 ; of Chitten-
den's subjects, 124; of juar, 55 ; of
pulses, 59 ; of pulses, effects of bulk
on, 64 ; of tropical foods, 65 ; uni-
form from identical diets, 126

Acid intoxication and acidosis, 12

Acids, monamido and diamido, 5

Afridis, characteristics of, 206

Ainus, 28

Albuminuria in Bengalis, 172

Amino-acids, 2

Ammonia : in portal vein, 6 ; impor-
tance of, in acidosis, 12 ; Schryver's j
views on, 13

Analysis of Indian foods, 32

Andamancse, 28

Aneurism rare in Hindus, 176

Anglo-Indian and Eurasian students :
as athletes, 138 ; diets of, 161, 171 ;
effects of diet, 162, 171

Army rations : caloric value of, 71 ;
protein content and heat value of, j
74

Aron : influence of a restricted diet on |
dogs, 208 ; protein absorption of j
rice, 38

Aryo-Dravidian physical type, 190

Atwater and Bryant, composition of ,
foods, 31

Atwater, standards of dietaries, 71

Bajouris, characteristics of, 206
Bajra : chemical composition of, 55 ; !

protein absorption of, 55
Baluchis, characteristics of, 206

Barley : chemical composition of, 54 ;
protein absorption of, 55

Bedouins in Arabia, meat diet, 88

Benedict : caloric value of Indian
foods, 33 ; diets of low caloric value,
116 ; criticism of protein absorption
of Chittenden's subjects, 124 ; ex-
planation of non-uniformity of
protein absorption, 125 ; effects of
diets deficient in protein, 139 ; ex-
periments on energy requirements,
146 ; needs of the body for food, 69 ;
requirements of different classes, 70

Bengal infant, average weight of, 94

Bengal mother's milk : composition
of, 92 ; amount secreted, 92

Bengal students and servants, 76 ;
contrasted with Japanese, 77 ; and
Chittenden's standard, 77

Bengal students : diet at college, 161 ;
physical development of, 160, 162 ;
as athletes, 139

Bengali : capacity for work, 166 ;
characteristics in underfeeding, 175 ;
classes contrasted, 181 ; diet of,
Chittenden's misconception, 81 ;
diet of, not ill-balanced, 82 ; de-
ficiency in body fat, 98 ; deficiency
in haemoglobin, 158 ; chemical com-
position of blood, 157 ; chemical
composition of urine, 156 ; blood-
pressure of, 157 ; effects of under-
feeding on, 159 ; physical develop-
ment of, 164 ; physical endurance
of, 165 ; life expectation in, 167 ;
life insurance amongst, 168 ; protein
metabolism of, 157 ; renal disease
in, 172, 174 ; resisting powers to
disease, 171 ; resistance ol acute
infections, 172, 174 ; not a soldier,
183

Bhutia : classes of, 184 ; development
of, 185 ; protein metabolism of, 187 ;
Sikhim, diet of, 86, 187 ; Tibetan,
diet of, 86, 187

Bleaching of flour, 47

Brahmin proverb, 154

211

212

THE PROTEIN ELEMENT IN NUTRITION

Bread, "standard," advantages

claimed, 46
Browne, Crichtcn : criticisms of Chit-

tenden's views, 102 ; diets, mixed

and vegetable, 26
Brunton, Sir Lauder, experiments on

food, 67
Buchanan, Lt.-CoL, observations on

physique of the Bengali, 164
Buckle, effects of an increasing supply

of food, 25

Buddhism, diet allowed, 25
Bulkiness of diets, effects of, 40
Bunge, the pessimist's view of physio-
logical research, 21
Bushmen of South Africa, diet of,

88

Caddy, Dr. A., life insurance in India,
168

Caloric value : army rations, 71 ;
Indian foodstuffs, 32 ; tropical
dietaries, 97

Cambridge, on the food of " Indians,"
151

Campbell, Dr. Harry : conclusions
regarding diet, 30 ; on the evolution
of man's diet, 26

Carbohydrate group of cleavage of
proteins, 5

Carbonaceous metabolism, an aspect
discussed, 97

Caspari and Glassner, observations on
vegetarians, 118

Cathcart, on crcatinine and diet, 17

Causes of rejection for life insurance
in India, 170

Chemical composition : of different
parts of wheat, 45 ; of different
types of flour, 46

Chittenden : criticism of his observa-
tions on students, 118 ; criticism of
his observations on his three groups
of subjects, 132 ; experiments on
six laboratory assistants, 83 ; ex-
periments on six dogs, 140 ; experi-
ments on six dogs criticized, 141 ;
importance of his work on nutrition,
68 ; on Folin's view of the signifi-
cance of creatinine, 20 ; on the
dietaries of Bengalis, 81, 178 ; on
the dietetic customs of mankind,
101 ; on his own metabolism, 114 ;
standard of nitrogenous metabo-
lism, 118 ; standard of students'
metabolism, 118 ; studies with three
groups of subjects, 116 ; standard
of nutrition exemplified in the
Bengali, 77

Church, on the digestibility of the
protein of pulses, 61

Cibicultural epoch in the evolution of
diet, 27

Coefficient : of absorption of Indian

foods, 65 ; of protein absorption,

low, in certain foods, 56
Conqusring races all high protein

feeders, 140
Conservation of energy, law of, applied

to Chittenden's experiments, 115
Convict prisons of England, diets of,

135
Cooking, effects of, on digestibility of

pulses, 61
Cows, effects of feeding on diets low

in protein, 142
Cramer and Krause, effects of thyroid

feeding on creatinine excretion, 19
Creatinine-nitrogen and diet dis-
cussed, 15, 103
Crichton - Browne, on the effects of

diets poor in protein, 133
Cultivators, Bengal, diet of, 78

Dais : chemical composition of, 57 ;
different forms in use, 57 ; how used
as food, 58 ; importance of, as a
source of nitrogen, 58
Deficient protein, effects of, 144
Demerits of diets poor in protein, 145
Denitrifying action of intracellular

enzymes, 6
Determining influence of diet on

Bengalis, 181
Diamido-acids, 5

Diet : of the Sikh, 90 ; of prisons of
England, effects of, 136 ; poor in
protein, effects of, 113
Dietary standards, 68
Dietary studies in Bengal : students
and servants, 76; professional class,
78 ; all classes, 78 ; students in resi-
dence, 80; hill-tribes, 86; aborigi-
nal tribes, 88; infants' diet, 92
Dietary studies : in Europe and
America, 70 ; in India, fighting
castes, 89

Dietetic customs : of mankind, Chit-
tenden on, 101 ; of fighting castes,
184

Digestibility of different foods, 33
Disease and underfeeding, 133
Dogras : as soldiers, 183, 198 ; char-
acteristics of, 194 ; effects of diet on,
195 ; physical development of, 193
Dogs, experimental feeding of, 140
Dorner, on creatinine and diet, 17
Dynamic effects of a high protein diet,
123

Economy of Chittonden's standard in

India, 153
Effects of diet on the fighting races

of the Punjab, 201, 204, 207
Effects of low protein metabolism : on

the Bengali, 178 ; on animals, 144

INDEX

213

Effeminacy of " Indians," 149
Efficiency and the amount of food

(Spriggs), 122
Endogenous metabolism, Folin's views

on, 15
Energy : a property of the nervous

system, 153 ; potential of tropical

dietaries, 97
Energy requirements : Benedict and

Carpenter, 147 ; of Chittenden's

froups of subjects, 146, 148 ; of
letcher, 146

Errors, possible, in Chittenden's obser-
vations, 145

Esquimaux, 23

Eurasian and Anglo-Indian students :
as athletes, 138 ; diets of, 161 ;
physique of, 160, 162

European and Bengali infants con-
trasted, 94

Examination, critical, of Chittenden's
results, 127

Excess excretion of waste products,
123

Exogenous metabolism, 15

Experiments, Chittenden : on three
groups, 116; on three groups, results,
117 ; on six laboratory assistants, 83

Experiments to determine the pre-
sence or absence of the beri-beri
vitamine in Bengal food-materials,
210

Feecal carbohydrates not a true
measure, 97

Faecal nitrogen : average amount of , in
Bengalis, 83 ; a true measure, 98 ;
of Chittenden's subjects, 125 ; of
Chittenden's assistants, 84 ; on
certain vegetable diets, 57

Famine and the incidence of disease,
134

Fasting, excretion of nitrogen during,
105

Favourable results ascribed to low
protein dietary, 130

Feeding on the cleavage products :
of intestinal digestion, 4 ; of acid
hydrolysis, 4

Fermentation, intestinal, as a cause
of loss of potential energy, 97

Fischer : researches into the compo-
sition of protein, 4 ; synthesis of
polypeptides, 6

Fisher, Irving, on effects of diets poor
in protein, 138

Flack and Hill , the nutritive value of
flours, 52

Fletcher, energy requirements of, 146

Flour : bleaching of, 47 ; false stand-
ard of millers, 49 ; wholemeal,
chemical composition of, 46 ; stand-
ard, 47

Folin : deductions from urinary creati-
nine discussed, 103 ; significance of
constancy of creatinine output, 15

Food : its functions, 23, 96 ; of Brah-
mins, 150

Food-materials of India, absorption
of, 65

Food requirements of different classes,

70

| Foods : American and European,
analyses of, 32 ; Indian, analyses of,
32

I France, prison diets of, 137
| Fuegians, diet of, 23

Funk, isolation of beri-beri vitamine,
52, 209

Gaols of Bengal : dietaries of, 81 ;
dietaries ill-balanced, 82

Gaols of India, absorption of protein
of pulses, 62

Gautier, Dr., on prison diets of France,
137

Glycosuria in Bengalis, 172

Goodfellow, on the nutritive value of
Hovis bread, 45

Graham flour, absorption of con-
stituents of, 50

Granular kidney in different races in
India, 177

Grinding-stones in India, 45

Haecker, on feeding cows on low

protein diets, 144

Hagemann, experiments on dogs, 140
Hale, on the effects of nitrites in flour,

48
Halliburton, on the effects of nitrites

in flour, 47
Hamill and Schry ver, observations on

scientists, 118
Hansen and Henriques, <.xperiments

on rats, 3
Harcourt, absorption of protein of

maize, 53
i Harden, effects of bleaching on flours,

48
Hill and Flack, the nutritive value of

flours, 52
Hill-tribes of Bengal, characteristics

of, 184
Hindus : acute infection in, 175 ;

atheroma and granular kidney in,

177 ; diet of, 24 ; mortality rates of,

167 ; renal disease in, 174
Hoesslin, effects of underfeeding on

the blood, 159

Hofman, protein absorption of vege-
table diets, 41
Hogs, effects of a low protein diet on,

143, 144

Hoogenhuyze and Verploegh, on crea-
tinine excretion, 17

214

THE PROTEIN ELEMENT IN NUTRITION

Hopkins : on the elaboration of supra-
renal secretion, 8 ; and Willcock, on
the protein of maize, 7

Hutchison : criticism of Chittenden's
views, 101 ; degrees of health, 153 ;
on the effects of diets poor in
protein, 133 ; on the merits of a high
protein standard, 123 ; table of co-
efficients of absorption of food con-
stituents, 34 ; vegetable protein ab-
sorption, 42

Ill-balanced dietaries of Bengal gaols,
82

Ill-effects of low protein dietaries, 146

Improvers, effects of, on weak wheats,
48

India, dietary studies in : students and
servants, 76 ; professional class, 78 ;
all classes of Bengalis, 78 ; different
classes of students, 85 ; hill-tribes
of Bengal, 86 ; aboriginal tribes of
Chota Nagpur, 88 ; fighting castes,
Sikh, 89 ; Bengali mother's milk
and infant's food, 92

Indian corn or maize as a food, 52

Indian corn, protein absorption of, 53

Indian dandywallahs v. Japanese jin-
ricksha men, 75

Indian food-materials : absorbability
of, 65 ; analyses of, 32

Indian v. Anglo-Indian students as
athletes, 139

Indo-Aryan physical type, 189 ; in-

' fluence of diet on, 205

Influence : of certain substances (vita-
mines) on nutrition, 208 ; of diet on
physique of hill-tribes, 187 ; of high
protein metabolism on the fighting
races of India, 206

Insufficient protein, effects of, 131

Insurance, life, and the Bengali, 168

Intestinal fermentation and loss of
potential energy, 98

Irregularity of Chittenden's figures
for protein absorption, 127

Jaffa, protein absorption of fruits, 35
Jagerroos, experiments with dogs, 140
Japan, dietary studies in, 72
Japanese Navy, effects of a change of

diet, 76

Jat Sikh, diet of, and physique of, 200
Jats, classes of, and diet of, 199
Jinricksha man, dietary study with, 74
Juar : chemical composition of, 55 ;

protein absorption of, 55

Kaufmann and Murlin, experiments

with gelatin, 7
Kellogg, effects of a low protein

dietary, 179
Kidney disease in Bengal, 172, 173

j Kossel, researches on protein, 4
Krause and Cramer, thyroid feeding

and creatinine excretion, 19
Kristeller and Levene, investigations

on creatinine, 18
Kuhne, the action of trypsin, 3

Landois, weight for height rule, 165
Langworthy, absorption of foods, 35
Leathes, explanation of acid and

tryptic hydrolysis, 4
Leguminosae, foods derived from, 57
Leowi, feeding with products of

tryptic digestion, 3
Levene and Kristeller, researches on

creatinine, 18
Liebig : distinction between animals

and plants, 2 ; view of nitrogenous

metabolism, 15
Livingstone, diets of tribes of Central

Africa, 137
Local Government Reports : on

bleaching of flour, 47 ; on use of

improvers, 48
Loeser : observations on Transvaal

miners, 148 ; statement regarding

diet of Chittenden's soldier group,

148

Lower limits of nitrogenous equi-
librium, 106
Lymphocytosis and a diet of raw

meat, 134

Macaulay, characteristics of the Ben-
gali, 154

Maize : as a food, Woods on, 54 ;
protein content and protein ab-
sorption, 53

Malnutrition of renal epithelium ac-
companying chronic underfeeding,
123

Margin of safety (Rubner), 113

Mellanby, researches on creatinine, 17

Melville, Lt.-Col., R.A.M.C., on pro-
tein requirements, 207

Michaud, effects of feeding dogs on
dog's flesh, 7

Middle classes of Bengal, diet of, 79

Milk, Bengali mother's : chemical
composition of, 92 ; quantity se-
creted daily, 93
| Minimum, physiological, of protein

metabolism, 106

• Minimum protein diet, howobtained, 12
j Mixed form of dietary amongst pre-
cibiculturists, 88

Mohammedans : acute infectious dis-
eases of, 175 ; atheroma and granu-
lar kidney of, 177 ; mortality rates
of, 167 ; renal disease of, 174

Monamido-acids, 5

Montesquieu, on the effeminacy of
" Indians," 149

INDEX

215

Mongolo-Dravidian physical type, 188
Mongoloid physical type, 189
Moore, isolation of vitamine from

yeast, 209
Mullick. on the effects of underfeeding

of students, 135
Mundas, diet of, 88
Munk, experiments on dogs, 140
Murlin and Kaufmann, experiments

with gelatin, 7

Nencki, on the amount of ammonia in
portal blood, 11

Nepalese : diets of, 86 ; classes of, 184 ;
contrasted with their neighbours,
186 ; development of, 186 ; nitro-
genous metabolism of, 188

Nietzsche, on the effects of a great
error in diet, 134

Nitrites as bleachers of flour, effects
of, 47

Nitrogen : excretion of, during muscle
work, 109 ; of urine not a true
measure of protein metabolism, 119

Nitrogenous metabolism : level of, in
different classes of Bengalis, 87,
118 ; lower limits of, 106 ; standard
fixed by Chittenden, 118 ; students
in America, 119 ; ideal level of, 164

Nutrition, its problem, 155

Organic bases present in foods (vita-
mines), 52, 209

Orme, characteristics of " Indians,"
149

Oshima, absorption of protein : of rice,
38 ; of pulses, 59

Oshima, dictaiy studies : in Japan,
72 ; with jinricksha man, 74

Oshima, rice not the only food of the
Japanese, 73

Pampas, Indians of, 23

" Patents," finest flour, chemical com-
position of, 46

Pathan, characteristics and dietary of,
205

Paton : on creatinine and diet, 17 ;
on the role of protein in muscle
work, 108

Pators, diet of, 88

Peptides, Fischer on their derivation, 4

Pfliiger's views on nitrogenous meta-
bolism, 15

Physique to be expected with Chit-
tenden's standard, 131, 178

Pig, experimental feeding of, 143

Potential energy, loss of, in urine and
faeces, 96

Prausnitz, on the absorption of protein
of pulses, 59

Precibicultural epoch in the evolution
of man's diet, 27

Precibiculturists and a mixed form of
alimentation, 88

Precookery, 27

Pre-mortal rise in nitrogen excretion,
106

Prison dietaries : in France, 137 ; in
Scotland, 136

Protein : a nerve food, 153 ; as a source
of energy for muscle work, 108 ; of
dietaries of Bengali and Eurasian
students, 162

Protein absorption of Chittenden's
subjects, 124

Protein material : its importance, 1 ;
from animal and vegetable king-
doms contrasted, 8

Protein metabolism : ideal level of,
164 ; of different tribes in Bengal, 87,
89; of jinrickshaman in Japan, 75;
of students in America, 119 ; of stu-
dents and servants in Bengal, 76;
Sikh, 91 ; standard recommended by
Chittenden, 118; lower limits of,
106

Protein requirements of mankind, 96

Protein-poor dietaries, observations
by different observers, 114

Pulses : importance of, as a food in
India, 58 ; protein absorption, in-
vestigations, 59

Pyrimidine group in the cleavage of
proteins, 5

Pyrrol group, 5

Races of the Gangetic Plain, 188
Rajputs : as soldiers, 183 ; classes of,
191 ; influence of diet on, 192 ;
physique of, 193

Rations, army, caloric value of, 71
Recruits, rejection of, and under-
feeding, 123

Renal disease in Bengal, 173, 174
Renal epithelium, malnutrition of, 172
Rice : absorption of the protein ele-
ment, 38 ; as the staple food of
parts of India, 37 ; classes of, 37
Rice diet : bulkiness of, 38 ; not the
principal food of India, 151 ; the
cause of effeminacy, 150
Richter, absorption of protein of

pulses, 59

Risley, the people of India, 181, 189
Roberts, food customs of mankind,

importance of, 102
Rogers : analysis of post-mortem
records, 173 ; effects of diet on
mortality, 176

Rosenheim, experiments on dogs, 140
Rowntree, effects of underfeeding, 123
Rubner, absorption of protein : of

maize, 53 ; of pulses, 59
Rubner, margin of safety, 113
Russell, strength and diet, 68

216

THE PROTEIN ELEMENT IN NUTRITION

Sawanis, diet of, 88

Schryver, role of ammonia in meta-
bolism, 13

Schutzenberg, composition of protein,
4

Scotch prisoners, diet of, 136

Scrafton on the food of " Indians,"
151

Sexual excess in India, 180

Shaffer, excretion of creatinine, 17

Shutt, experimental feeding of hogs,
143

Sikh : as a soldier, 184, 202 ; effects of
diet and Sikhism on, 204 ; dietaries
of, 90, 203 ; nitrogenous metabo-
lism of, 91 ; not a vegetarian, 91 ;
physique of, 204

Sikh, Jat : as a soldier, 200 ; physique
of, 201

Siven, exp rimenta with diets poor in
nitrogen, 113

Skinner, experimental feeding of hogs,
144

Snyder : experiments with prepara-
tions of wheat, 50 ; on the protein
absorption of pulses, 59

Soldier group of Chittenden, Loeser on
their diet, 148

Solitary cells for prisoners under ob-
servation, 132

Spriggs, quantity of food necessary
for efficiency, 122

" Standard " bread : advantages
claimed for, 46

Standard dietaries, table of, 69

Standard dietary, 68

Starvation and the nitrogen require-
ments, 105

Stewart, on the metabolism of proteins,
110

Strachey : on Indian foodstuffs, 151 ;
on the characteristics of the Ben-
gali, 154

Strength, increase of, in Chittenden's
subjects, 124

Strumpell, the effects of cooking on
protein absorption, 66

Students, Chittenden's observations
on, 119

Studies, dietary : in Europe and
America, 70 ; in Bengal, 76

Sudra, caste or class of, 194

Sulphur-carrying group in the cleav-
age of proteins, 5

Summary of criticisms of Chittenden's
conclusions, 132

Tibetan Bhutias : diet of, 86, 187 ;

physique of, 185

Tiegel, on the food of the Japanese, 75
Todas : diet of, 88 ; ignorance of salt,

88

Torulin of yeast (Moore), 209
Types, physical : of India, 187 ; effects
of diet on, 188

Underfeeding, effects : on Bengali,
159 ; on blood, 159 ; of, in disease,
133

Uraons, diet of, 88

Urinary nitrogen : as a measure of
protein metabolism, 119, 132 ; of
Chittenden's subjects, 129

Urine of Bengalis, chemical compo-
sition of, 156

Vaisiya, caste of, 194

Vedas, hymns in Sanskrit language,

193

Veddahs of Ceylon, 28
Vegetarian couple, observations on,

118

Vegetarianism in India and Japan, 72
Verploegh, creatinine metabolism, 17
Verworn, the metabolism of proteins, 1
Vitamine of beri-beri (Funk), 52, 209
Voit, standard of protein : in diet, 101 ;
contrasted with Chittenden's stu-
dents, 121

V. Noorden : high protein feeding and
health, 124 ; table giving experi-
ments with diets poor in protein,
114 ; table showing results of Chit-
tenden's experiments, 117 ; working
man's demand for protein, 100

Wait, absorption of protein of pulses,

59

Waller, the state of nutrition, 153
Waste products, excess in the urine,

123

Waziris, characteristics of, 206
Weber, creatinine and muscular ac-
tivity, 20
Weight of European and Bengali

infant, 94
Weir-Mitchell treatment and high

feeding, 134
Wheat : protein content and protein

absorption, 43 ; protein absorption

in India, 44

Wheat-meal, composition of, 46
Willcock and Hopkins, experiments

with zein, 7

Winter, life insurance in India, 168
Woodruff, Major, U.S.A. : actinic rays,

effects of, 180 ; on diets in the

tropics, 24

Woods, on maize as a food, 54
Work : demand for protein in severe,

100 ; source of energy in, 107

Zieman, on the influence of diet on the
tribes of tropical Africa, 138

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LESLIE BARNARD, M.S. F.R.C.S., Late Assistant Surgeon, London Hospital. xix+3Qi
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Movable Kidney : its Pathology, Symptoms, and

Treatment. By H. W. WILSON, M.B., B.S. Lond., F.R.C.S. Eng., Demonstrator of
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Fractures and Separated Epiphyses. By A. J.

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The Chemical Investigation of Gastric and In-

testinal Diseases by the Aid of Test Meals. By VAUGHAN HARLEY, M.D. Edin.,
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FRANCIS GOODBODY, M.D. Dubl., M.R.C.P., Assistant Professor of Pathological Chemistry,
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The Influence of Alcohol and other Drugs on

Fatigue. By W. H. RIVERS, M.D., F.R.C.P., F.K.S., Lecturer on Physiological and
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Modern Theories of Diet, and their Bearing upon

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The Chemical Basis of Pharmacology, An Intro-

duction to Pharmaco-dynamics Based on the Study of the Carbon Compounds. By
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J. M. FORTESCUE-BRICKDALE, M.A., M.D. Oxon. 384 pages. 145. net.

A Manual of Pharmacology. By WALTER E.

DIXON, M.A., M.D., B.Sc. Lond., D.P.H. Camb., Professor of Materia Medica and
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Military Hygiene and Sanitation. By Col. C. H.

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The Sanitary Officer's Handbook of Practical

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BOOKS FOR NURSES.

Surgical Nursing and the Principles of Surgery for

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Midwifery for Nurses. By HENRY RUSSELL

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6 FROM MR. EDWARD ARNOLD'S LIST

INTERNATIONAL
MEDICAL MONOGRAPHS

GENERAL EDITORS :

LEONARD HILL, M.B., F.R.S.,

Lecturer on Physiology, London Hospital Medical School

WILLIAM BULLOGH, M.D.,

Bacteriologist and Lecturer on Bacteriology and General Pathology,
London Hospital.

TN this series, under the general editorial supervision of Dr. Leonard
Hill and Dr. William Bulloch, will be published at short intervals
Monographs dealing with subjects of exceptional interest and importance,
each by a leading authority, who has made a special study of the
particular subject.

Readers interested in any special branch of medical science, or who
are following the rapid progress of knowledge in some new phase of
research will, it is hoped, find in a concise form the results of the leading
investigators throughout the world. The practising physician also will
find the volumes of great value, special attention being given to the
practical application of the results of scientific research to the treatment
of disease.

On the following pages is given a list of the volumes just published
and those which it is hoped will be ready shortly ; new Monographs will
be added from time to time as occasion arises.

Each work can be obtained separately. Further particulars of any of
the volumes in the International Medical Monograph Series, together
with specimen pages, will be sent on request by the Publisher.

OF MEDICAL BOOKS

INTERNATIONAL MEDICAL MONOGRAPHS.

THE MECHANICAL FACTORS
OF DIGESTION.

By WALTER B. CANNON, A.M., M.D., George Higginson Pro-
fessor of Physiology, Harvard University, xii + 227 pages, cloth,
illustrated. IDS. 6d. net.

SYPHILIS :

A SYSTEMATIC ACCOUNT OF SYPHILIS FROM THE
MODERN STANDPOINT.

By JAMES MC!NTOSH, M.D. Aberd., Grocers' Research
Scholar; and PAUL FILDES, M.B., B.C. Camb., Assistant to the
Bacteriologist of the London Hospital, xvi + 228 pages, illus-
trated with 8 Full-page Plates and 5 Diagrams, cloth. IDS. 6d.
net.

BLOODVESSEL SURGERY AND
ITS APPLICATIONS.

By CHARLES CLAUDE GUTHRIE, M.D., Ph.D., Professor of
Physiology and Pharmacology, University of Pittsburgh, etc.
xii + 350 pages, 158 Illustrations, cloth. 143. net.

CAISSON DISEASE AND DIVER'S

PALSY.

THE ILLNESS OF WORKERS IN COMPRESSED AIR.

By LEONARD HILL, M.B., F.R.S., Lecturer on Physiology,
London Hospital. IDS. 6d. net.

8 MR. EDWARD ARNOLD'S MEDICAL BOOKS

INTERNATIONAL MEDICAL MONOGRAPHS

LEAD POISONING AND LEAD
ABSORPTION :

THE SYMPTOMS, PATHOLOGY AND PREVENTION, WITH
SPECIAL REFERENCE TO THEIR INDUSTRIAL ORIGIN AND
AN ACCOUNT OF THE PRINCIPAL PROCESSES INVOLVING

RISK.

By THOMAS M. LEGGE, M.D. Oxon., D.P.H. Cantab., H.M.
Medical Inspector of Factories ; Member of the Committee on
Compensation for Industrial Diseases ; Lecturer on Factory
Hygiene, University of Manchester; and KENNETH W. GOADBY,
D.P.H. Cantab., Pathologist and Lecturer on Bacteriology,
National Dental Hospital.

THE PROTEIN ELEMENT IN
NUTRITION.

By Major D. McCAY, M.B., B.Cn., B.A.O., M.R.C.P. Lond.,
I. M.S., Professor of Physiology, Medical College, Calcutta;
Examiner in Physiology, Calcutta and Punjab University.

SHOCK :

THE PATHOLOGICAL PHYSIOLOGY OF SOME MODES OF

DYING.

By YANDELL HENDERSON, PH.D., Professor of Physiology,
Yale University.

THE CARRIER PROBLEM IN
INFECTIOUS DISEASE.

WITH PARTICULAR REFERENCE TO

ENTERIC FEVER, DIPHTHERIA, CEREBRO-SPINAL MENIN-
GITIS, BACILLARY DYSENTERY AND CHOLERA.

By J. C. G. LEDINGHAM, D.Sc., M.B., M.A., Chief Bacterio-
logist, Lister Institute of Preventive Medicine, London ; and
G. F. PETRIE, M.D., Lister Institute of Preventive Medicine,
London.

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