NationalLibraryOfScotland/medical-history-of-british-india huggingface dataset:
15
evident, assuming as before that 85 per cent. of the protein of rice is absorbed so
long as the quantity of rice does not exceed a certain amount, that if we increase
the quantity of rice beyond this amount, even if a smaller percentage of the
protein is absorbed, the now greater quantity of protein from the increased amount
of rice multiplied by a slightly diminished co-efficient of absorption will give an
actually greater quantity of protein undergoing metabolism in the body. This
will hold true up to a certain limit and when this is passed, the actual amount of
protein undergoing metabolism will diminish instead of increasing as more and
more rice is added to the diet. An illustration will make this line of reasoning
clear:—
Supposing 5 grammes of nitrogen in the form of rice to be the maximum
amount from which full absorption takes place, then 5 X 0.85 =
4.25 grammes is the amount of nitrogen undergoing metabolism.
Now assume that for every increase of 1 gramme of nitrogen in the form of
rice there is a fall of 10 per cent. in the co-efficient of absorption then :—
6 grms. nitrogen x . 75 gives 4. 50 grms. undergoing metabolism
7
8
"
"
"
"
X
x
. 65 "
.55 "
4.55
4.40 "
"
"
so that we obtain the maximum absorption in our illustration with 7 grammes,
and the amount of rice present in the diet from which this maximum absorption
takes place we may call the optimum amount ; of course, it is understood that all
other constituents of the diets remain constant.
Basing our investigations on this principle we have worked out the optima
amounts of the different food-stuffs made use of in the dietaries of Lower Bengal
and Behar, and plotted our results out in. the form of curves of absorption under
varying quantities of each different food material whilst all other constituents are
kept constant. It will be readily admitted that, having found the particular
quantities of the different food-stuffs from which the greatest amount of protein
is absorbed, we have got the particular quantity of each food-stuff that is the most
useful to the body, and, therefore, the most economical so far as that type of diet
is concerned; and, by combining those quantities of the food-stuffs available in
Bengal and Behar, we get diet scales based on the real nutritive value of the foods
of the country. It will be evident that investigations carried out on this plan
entailed an immense amount of work as compared with the simpler methods in use
in Europe and America. Instead of our being able in a few experiments to obtain
the nutritive value of a "basal diet" and then add rice, wheat ata, different dais
or makkai ata to it, and calculate from the percentage of the extra amount
absorbed the co-efficient of protein absorption for each food-stuff, for every
food-stuff a whole series of experiments had to be carried out to obtain its curve
of absorption under varying conditions.
16
Thus for wheat ata in the Behar diet we had to arrange for a series of diets
on the following plan :—
x Rice
y Dal
zVegetables
I
a Wheat ata Diet I.
b "
"
" II.
Constant + .
. c "
"
" III.
d "
"
" IV.
e "
"
" V.
[ Each of these diets entailed one week's work ].
a, b, c, d, and e are gradually diminishing quantities. And the same had to.
be done to get the curve of absorption for the protein of rice and to a smaller ex-
tent also for dal. To have done this for all the different kinds of dais in use would
have taken months of work, and more time than we could spare ; it was, therefore,
carried out for two of the principal dais, and by other methods of investigation the-
relative nutritive value of the other kinds of dal was estimated. Besides investi-
gations of this nature to discover the quantities of the food-stuffs and the combina
tions of those quantities from which the maximum absorption is obtainable, many
other observations on the effects of meat, fish, wheat ata on Bengalis, etc., were
carried out. Some most interesting results were obtained, amongst the more
important of which were the influence that an animal protein exerts in causing an
increase in the protein absorption seemingly out of proportion to the a mount of
protein it contains, and the favourable influence that wheat ata has on protein
absorption when it is added in small quantities to the ordinary Bengali diet.
We have discussed the nutritive value of Indian jail dietaries nearly always
from the point of view of the absorption of protein, leaving the carbo-
hydrates and fats out of consideration. This is due to the fact that protein is of
pre-eminent importance in a diet. Major Macnamara sums up the reasons
for attaching much greater importance to protein than to the other proximate
principles as follows :
—
1. A certain amount of nitrogenous substance must be present in all
dietaries, and cannot be replaced by any other aliment.
2. All nitrogenous articles of diet also contain carbon, whilst all carbon-
aceous substances do not contain nitrogen.
3. All diets composed largely or entirely of vegetable substances, such
as are those of the natives of this country, are not likely to be deficient
in carbon if the nitrogenous principles are present in sufficient
amount.
We shall have more to say regarding the excess of carbohydrate in the Bengal
jail dietaries when we come to the work dealing with the composition of those
dietaries.
17
At present it will be sufficient to point out that abundant experimental evi-
dence has accumulated to show that the nutritive values of the fats and carbo-
hydrates of food are almost proportional to the amount of energy that they can fur-
nish ; 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 the diet, shall
supply the amount required by the body. The maximum amount of energy that
can be obtained by the body is not the total potential energy of the food con-
sumed, since the potential energy of the corresponding fæces must be deducted.
Furthermore, the body is not capable of completely oxidising the absorbed protein,
the incompletely oxidised products being excreted in. the urine, and the energy
eliminated in this way must also be deducted. The net or actual energy-value to
the body is the total potential energy of the food minus that of the corresponding
fæces and urine.* In dealing, however, with the vegetarian dietaries in force in
Indian jails another factor has to be considered with regard to the energy or fuel
value of a diet ; this factor is the excessive fermentative processes in the digestive
tract. Anyone who has experience of the effects of excessive carbohydrates in the
diet will readily recognise the clinical features of excessive intestinal fermentation
in the noisy eructations, flatulency, tendency to diarrhcea and colic and, above
all, the changes in the appearance and character of the fæces—soft from admixture
with gas, and light brown to yellow in colour for the same reason—exhibited,
sometimes in a marked degree, by the prisoners examined by us.
This excessive fermentation of carbohydrates constitutes an important
source of loss of potential energy of the diet, through the conversion of sugar or
starch into carbon dioxide and fermentative products of low caloric value, such
as acetic acid, lactic acid, etc.
This loss, which may be large in amount depending on the degree of fermenta-
tion present, will reduce the fuel value of the diet very considerably, and may
afford a likely explanation of the remarkable want of body fat in many of
the ordinary working population of Bengal. The loss of fuel from fermenta-
tion being so considerable that, although the diet is exceedingly rich in carbo-
hydrate material, none or only a minimum can be stored and even in some cases
where under-nutrition is well-marked, the body tissues are drawn on to meet the
caloric requirements. This method of waste due to excessive carbohydrates in
the jail dietaries of Bengal is, we believe, a most important factor and one that
must be taken into consideration not only in calculating the fuel value of the diets
but also in connection with the intestinal troubles that are so prevalent in Bengal
jails and indeed amongst the people generally.
So far as we know there is no method by which this loss can be even approxi-
mately computed ; but that it is an important factor in reducing the fuel value of
* The narrative requirements of the body. Benedict, American Journal of Physiology, Vol. XVI, No. IV.
18
the food will be readily admitted ; and it, therefore, introduces a fallacy into any
determinations of the energy requirements by the respiration calorimeter under
conditions of excessive fermentation.
No work has been done in India on the determination of the energy require-
ments of Indians of different size, age, sex and degrees of bodily activity. Accept-
ing that the law of the conservation of energy obtains in the human organism,
such work will require the determination of the energy-output per day in terms of
the total heat-output by means of the respiration calorimeter. Any calculation of
the heat-value obtained from the food that is based on the number of heat units
furnished by that food must, therefore, take into account the loss in the urine and
fæces, and the loss incidental to fermentation in the gastro-intestinal tract. We
have no observations on the total loss of heat in the urine and fæces of prisoners on
any of the diets investigated and, as stated above, there is no means of deter-
mining the loss due to fermentation.
We are, however, able to present the energy values of the different food-stuffs
in use in the jails of Bengal determined by means of the calorimetric bomb. For
these results we are indebted to the kindness of Professor Benedict of the Carne-
gie Institute of Washington, Boston, who, on hearing of these investigations, at
once offered assistance in the determination of the energy values of the food
- stuffs. To Professor Benedict we desire to express our thanks for the kindly
interest he has taken in the enquiry and. for the help he has rendered us.
We shall conclude what we have to say regarding the scope of the present
enquiry by giving a short, concise
Account of the work done.
1. All the different food-stuffs in use in the dietaries of Bengal and Behar
jails have been analysed. As will be seen from the tables of analyses this
involved a good deal of labour ; but in addition to these, which were all carried
out at the beginning of the investigation before work on nutritive value was
commenced, we almost invariably analysed the different food materials entering
into the composition of the dietaries whose nutritive value was being examined.
This was found necessary in order to obtain an accurate estimate of the total
protein intake ; the nutritive investigations being carried out during both the wet
and the dry seasons of the year differences in the percentage of moisture caused
considerable variations in the percentages of the different proximate principles.
This part of the work entailed about
—
300 Kjeldahl's estimations of total nitrogen.
180 determinations of carbohydrate.
130
"
" fat.
50
"
" moisture.
5 0
"
" ash.
19
In all 60 different samples of food-stuffs, obtained from seven different
jails in Bengal, were analysed.
2. Investigations were carried out in the following Bengal Jails :—
Presidency Jail, Calcutta; Central Jail, Midnapore; Puri Jail; Cen
tral Jail, Buxar ; Central Jail, Bhagalpur; RanchiJail;
Motihari Jail and Darjeeling Jail. Thus the different peoples.
of the Province were all included.
3. The number of prisoners in the different jails who were under observa
tion in the investigations were :—
Presidency Jail, Calcutta.
5 prisoners under observation for 19 days.
20
"
"
"
"
"
10
"
"
"
"
3 6 "
"
10
"
"
" 14
"
10
"
"
"
"
7
"
Total 55 prisoners investigated over a period of 112 days.
Midnapore Jail.
20 prisoners under observation for 19 days.
Puri Jail.
16 prisoners under observation for 18 days.
8
"
"
" 14
10
"
"
"
" 7
2 5
"
" 20
The whole jail—about 200 prisoners—has been under observation since 1st
January 1909, about six months.
The prisoners have been divided into two batches, and each batch has been
kept on a diet based on the information gained from these investigations.
A report of the results obtained will be found further on.
Motihari Jail.
25 prisoners under observation for 16 days.
Buxar Jail.
20 prisoners under observation for 52 days.
"
"
"
"
1 4 "
"
Bhagalpur Jail.
20 prisoners under observation for 7 days.
20
"
"
" 30
"
"
" 14
"
D 2
20
Ranchi Jail.
16 prisoners under observation for 14 days.
Darjeeling Jail.
13 prisoners under observation for 12 days.
12 "
"
"
" 1 2 "
12 "
"
" 10 "
In the work of investigating the nutritive value of Bengal Jail, dietaries
we have had over 250 prisoners under observation for 350 days. During this
time these prisoners were actually fed by us on a known diet, and their excreta
collected for analysis.
4. Chemical analyses—
(a) Determinations of total nitrogen—1,950—-which in addition to 300 in
food analyses brings the total Kjeldahl's determinations to 2,250.
[Every determination was done in duplicate in the analyses
of the excreta.]
This does not take into account a very large number of
controls, nor the determinations of urea as nitrogen.
(b) The total chlorides were estimated in every specimen of urine and
f æ c e s t h a t c a m e u n d e r e x a m i n a t i o n — t h e t o t a l e s t i m a t i o n s w o u l d
therefore be half the number of Kjeldahl's determination, but to
this must be added about 350 special salt-metabolism experiments,
bringing the total up to about 1,500.
(c) The free ammonia of the urine has been estimated on about 200
different occasions.
(d) A large number of observations have been made on the amount of
urea and its relationship to the total nitrogen. These determin-
ations were carried out by the Mörner-Sjöqvist process as
modified by Bodlker.
(e) The uric acid, purin bodies and phosphates have all come under
observation during the investigation.
5. Blood examinations
A large number of blood counts and hæmoglobin estimations have been
done in connection with the effects of salt on the system. We
have also made extensive enquiries as to the effects of large
amounts of salt on body-weight, on the percentage of corpuscles in
the blood, and on the percentage of chlorides in the serum ; but,
as the methods of accurately investigating the percentage of cor-
puscles requires much time and the use of an electric centrifugal
21
machine (which was not available in the different jails), no great
amount of attention was given to this part of the work on
prisoners ; a certain number of observations were, however, carried
out in the Physiological Laboratory on the menial staff and on
animals.
Methods of work.
6. A short account of our methods is necessary in order to give some
indication of the extent of the investigations; and at the same time it will
obviate any repetitions in the account furnished of our results.
I. Analyses of Food-stuffs and Excreta.—The food materials in use
in seven different jails in Bengal were analysed as regards their
protein, carbohydrate, fat, moisture and ash. As will be seen from
the tables of analyses, we were not content with a single analysis,
but made repeated analyses of the same sample to obtain an
average that would be, as far as possible, absolutely accurate. To
ensure this we estimated the protein in at least six samples—often
more—of the food-stuffs from the different jails, and never
accepted any result that departed more than 0.5 per cent. from
the average of the analyses closest to each other in amount. This
we considered necessary as the food-materials are often con-
taminated and it is difficult to obtain samples absolutely pure—
this remark applies particularly to the dals which are often mixed
with one another. As will be seen, we were able to obtain results
that are exceedingly close to each other, and may justly claim that
the average percentages presented are, for the samples analysed,
absolutely accurate.
The protein estimations were all carried out by the Kjeldahl
process as modified by Bernard Dyer. A modification which we
found of the greatest service was to add a few drops of a weak solu-
tion of phenolphthalein to the cross-tube leading from the distilla-
tion flask ; as soon as the ammonia begins to come over this indica-
tor becomes red and remains so until all the ammonia is distilled
over, when the colour disappears. By using this simple method a
great source of trouble in Kjeldahl's process is eliminated, viz., a
want of knowledge of the proper time to stop the distillation. It
will be evident that to lay down any definite time, such as half -an-
hour, as usually stated, is manifestly absurd : the time required will
depend largely on the source of heat used in the distillation, and
furthermore, we found that different samples of the same substance
22
often required different times for complete distillation of
t h e a m m o n i a . T o s t a t e t h a t t h e d i s t i l l a t i o n s h o u l d g o o n u n t i l
a certain quantity of fluid had passed over—one of the rules given
for guidance—is fallacious. We found that very varying quantities
of fluid passed over in different distillations before all the ammonia.
was collected. It is, therefore, most important to be able to say
definitely whether at the end of half-an-hour or at the end of an
hour, and whether we have distilled over 300 c.c. or 500 c.c. of
fluid—that we have obtained all the ammonia from the sample
and collected it ready for titration. This we are in a position
to do by using the simple method, here introduced and made use
of by us in over 2,000 Kjeldahls with the most gratifying results.
We have no hesitation in saying that 99 per cent. of the protein
estimations made in these investigations, in which two or more
samples of a urine or fæces were put up, the results obtained tallied
within a decimal place of each other, and in a very large pro-
portion absolutely identical results were obtained. We have found
that with proper care and by keeping the conditions the same the
most accurate results can be obtained. As a proof of this we were
able to point out to a firm of manufacturing chemists that their so-
called pure sulphuric acid contained a small percentage of
n i t r o g e n w h i c h t h e y s u b s e q u e n t l y a d m i t t e d t o b e t h e c a s e . T h i s w e
discovered from a comparison of the results of controls made with
this acid and that formerly in use. Estimations of the nitrogen,
in weighed samples of pure urea gave similarly accurate results,
when the distillation was stopped on the loss of the red colour
of our indicator.
Estimation of the ammonia of the urine :
—
I. The method followed in every instance was that described by Nencki
and Zaleski in which the urine, after liberation of all free ammonia
by the addition of ime water, is distilled in vacuo at a temperature
not exceeding 50°C. Here again we found the addition of a few
drops of our colour indicator of the greatest service in intimating
when the ammonia began to come over, and when all was over.
It simplified and shortened the whole process, besides affording
trustworthy evidence that we had obtained the full amount pos
sessed by the sample examined, and that our results were accurate.
The analyses and estimations of other constituents of the urine
and fæces were done by the ordinary methods described in text-
books and call for no comment from us.
23
The Carbohydrate of the food-stuffs analysed was estimated
by completely changing all the carbohydrate material into sugar
by the action of hydrochloric acid, and then estimating the per-
centage of sugar by Fehling's method, checking the results by
the Pavy-Fehling method or the Picro-Saccharometer.
The Fat was estimated in the usual way by means of
a slightly modified Soxhlet apparatus manufactured to our
drawings by Messrs. Baird and Tatlock, London.
The moisture and ash require no comment.
I I . T h e m e t h o d o f p r o c e d u r e w h e n w e c a m e t o i n v e s t i g a t i o n s o n p r i s o n e r s
was almost invariably to use as our unit a batch of five picked
prisoners—in a few cases we had four in the batch, in some
six and in some ten. The excreta from these five men—or from
the batch—were pooled, and in every case two samples of the urine
and two of the fæces—when examined—were put up fór nitrogen,
and a sample of each for chlorides ; one of the urine for ammonia
and sometimes the urea, phosphates, purin bodies, etc., of the
urine were also estimated. The specific gravity and reaction of
the urine was always taken. The weight of the prisoners making
up the batch was taken every day ; it was noticed that while
individual prisoners varied in weight from day to day, the average
weight of the batch after the first three or four days remained
practically constant.
The prisoners to form the subjects of the investigations having
been chosen, were isolated from the other prisoners. In the larger
jails we were able to make use of a block of cells with a common
yard where the work given to the prisoners could be carried out,
and where they were able to get air and exercise while at the
same time the facilities for feeding and collection of excreta were
much greater than was the case in the smaller jails. In the
smaller jails a large block of cells was not available for this
purpose ; we were always able however to obtain some godown
or store for the isolation of the batches.
The next step was to put the batches on the diet that we wished
to investigate. This was usually done for some days before any
col l ect i on of t he uri ne and fæces for anal yses was made, i n order t o
give time for the proper amount of protein to be absorbed and
nitrogenous equilibrium to be established, and to allow of the usual
increase in body-weight which we found to occur when the
prisoners were first put on a diet weighed and distributed by us.