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weight, failure of appetite, and general nutritive decline. That the
bones, too, are likely to be thin, fragile, pliable, and deformed. One
consi^icuous fact brought out by his experiments was that there was
quite an amount of the alkalies, sodium and potassium, in the bones poor
in lime. Magnesium, which was heretofore believed to replace the lime,
was not very plentiful. The deviations in the bones from the normal
showed least in the skull and were most marked in the ribs and spinal
vertebrae.

It might be expected from the foregoing that calcium salts would
benefit rickety children. Apparently such is not the case. There is
plenty of lime in the blood of children with rickets, but for some cause
the power of taking it from the blood and depositing it in the bones is
diminished. It looks as if lime starvation is merely an imitation of
rickets; for the bone cells, though still ready to deposit calcium, cannot
obtain it.

Very little is still known of the combination of lime Avith the ordinary
foods. An explanation of the way lime is present in milk or combined
in milk will shed some light on this question. It appears that lime
is in some way loosely combined with the proteins of milk or dissolved
in it in the form of an inorganic salt.^ Bunge has shown that it is not
present in any stable combination, though it is not definitely known
whether some other organic substance in the milk may not serve to keep
the calcium in solution in the presence of phosphoric acid.

In this connection Boswerth^*^ finds as the probable arrangement of
the constituents of human milk of average composition the following:
Fat, 3.30% ; milk sugar, 6.50% ; protein combined with calcium, 1.50% ;
calcium chloride, 0.059%; monopotassium phosphate (KH.-,PO^),
0.0697o; sodium citrate (IsTagCgH^O^), 0.055%; potassium citrate
(KgCgHgO^), 0.103%, and monomagnesium phosphate (MgH^P^Og),
0.027%. It has been observed by L. Vaudin^ ^ that citric acid in milk is
proportional to the lime contents.



PHYSIOLOGY AND CHEMISTRY. 37

This view of calcium being in combination Avith protein of milk lias
clinical support, i- The pediatrist in the treatment of infants suffering
from rickets urges as a prime consideration the administration of a
sufficient amount of proteins in the dietary.

It is probable that too much importance has been attached to the fat,
protein, and carbohydrate content of foods used as a substitute for
mother's milk. Xor can such a food be judged alone by its caloric value.
From our present knowledge of metabolism and food values, it should
be pointed out that a mistake is being made unless equal attention is
being given to the amount, as well as the chemic combination of the in-
organic salts in such substitute feeding.

We must constantly bear in mind that human beings and animals as
well, under certain conditions, as in growth, starvation, pregnancy, and
lactation, each have their peculiar drain upon the inorganic nutrients.
More publicity and investigation should be given to this subject, espe-
cially the influence of lactation upon calcium requirements.

Steinback and Hart,^^ in an investigation of this subject on animals,
point out that during lactation there is a drain on the skeletal lime
supply when there is an insufficient calcium assimilation. So during
the entire period of lactation the dietary should contain a liberal supj)ly
of lime. When we recall that most of our popular human food, such as
bread and meat, are w^anting in this important constituent, no astonish-
ment will be shown at an unusual drain on the maternal lime suj)ply
during lactation. It is yet to be announced just where the limit of
safety is in our ordinary dietary. Biologic investigation must make it
clear how foods should be adjusted to meet the needs of the human
organisms.

The acid and alkaline phosphates give to milk its characteristic re-
action. That is, milk is said to be amphoteric ; in carnivora, however,
fresh milk gives an acid reaction, but in most mammals the reaction is
alkaline, or more frequently amphoteric. These salts vary considerably
in different animals as well as at different stages of lactation.^"*

It is of interest here to note some recent studies by Clark^^ on the
reaction of cow's milk. Ordinarily, to determine the reaction of milk, the
alkaline constituent is estimated by titration with decinormal sulphuric
acid, w^ith blue lacmoid as an indicator and the acid constituent with
decinormal soda, with phenolphthalein as an indicator. 1*5 Clark points
out that such an index is of no value except to show the capacity of
milk to "neutralize" the added acid or alkali. He emphasizes the fact
that a true reaction can only be determined in terms of hydrogen (or
hydoxyl) ion concentration by electrometric methods. By this method



38 NORTH CAROLINA MEDICAL SOCIETY.

an exact departure from the reaction of normal breast milk can be ob-
tained where the ordinary practice of adding certain alkalies in the
process of modifying cow's milk is adopted. Such alkalies are chiefly
lime water. Bicarbonate of soda and milk of magnesia are added "to
correct the high acidity of cow's milk" and to prevent the formation of
a tough curd in the stomach.

Clark shows by his method that the addition of alkalies for the purpose
of neutralizing "the high acidity of cow's milk" is based upon the wrong
principle. He finds a normal average hydrogen-ion concentration of
human breast milk lies between 1.07 and .60 x lO''^, about the same as of
pure water at 30 degrees C. The introduction of 5% lime water has
a marked effect in distinctly lowering the reaction below that of normal
human milk. The average value obtained with 5% lime water used as a
dilution was 4.3 x lO'^. As Clark intimates, in modifying cow's milk
for infant feeding it would not be wise to allow the reaction to depart
from the normal hydrogen-ion concentration, 1.07 and .60 x 10"".

JSTot only is this fact brought out in this accurate determination of
the reaction of milk, but two other vital and important factors, which,
if true, would condemn the use of such alkalies as lime water, bicarbonate
of soda, and especially milk of magnesia. Wot only is this procedure un-
necessary, but it is one which involves, by reason of the presence of these
alkalies, an inhibitory action of both the proteolytic and lypolytic action
of the gastric juice upon milk.

If the use of alkalies is followed by the above mentioned facts, digest-
ive disorders may be initiated, resulting in slight or even serious intes-
tinal disturbances. Though such a disturbance may be at first slight,
we cannot underestimate the damage that may occur. For even a slight
disorder of gastric digestion is often marked by a rapid and fatal change
in the bacterial flora of the intestines.

We must recall, in this connection, that there are two antagonistic
bacterial processes occurring in the human intestines — fermentation and
putrefaction. In mother's milk the fermentative processes predominate,
while in cow's milk putrefactive changes have the ascendency. So, in
the breast-fed infant the former process holds true. Now, if the addition
of alkalies to cow's milk further favors a tendency to putrefactive
changes, we should certainly heed a timely admonition of Clark. He
says that the addition of alkalies to modified milk is criticised because
of its probable influence in displacing from the intestines a normal
bacterial fermentation and replacing it with those proteolytic or "putre-
factive processes which are responsible for many of the digestive dis-
orders of infancy."



PHYSIOLOGY AND CHEMISTRY. 39

The effect of boiling milk is a much discussed question. Clinical evi-
dence does not always agree with laboratory and animal experiments.
The effect of heating milk to or near the boiling point is said to lose
its antiscorbutic properties, a change in its natural flavor and the for-
mation of a scum on the surface. If this scum is removed it is rapidly
renewed. Its formation is due probably to coagulation of the lact-
albumen, which carries to the surface some caseinogen and fat.'" While
there are evident disadvantages in boiling milk, yet there are two well
recognized advantages: (1) All micro-organisms are destroyed; (2)
the gastric juice, by virtue of its pepsin or rennin, causes a flocculent and
not a bulky precipitate. The explanation of this is that by boiling a part
of the dissolved calcium salt is precipitated as a tricalcium phosphate.'^

A criticism of the first advantage accruing from the boiling of milk is
that there are ordinarily three general groups of bacteria found in
milk :i9

(1) The serobic nonsporulating organisms, the most abundant of
which are the lactic acid bacteria.

(2) The aerobic spore-bearing.

(3) The anaerobes.

In raAv milk the first group predominates, and as the milk ages this
group causes it to sour and clot. This may be looked upon as a desirable
change in milk, as the bacteria involved are nonpathogenic and may be
beneficial when taken into the alimentary tract. One of the reasons for
this is that this change which has occurred in the milk resembles very
closely that change which takes place in the human intestine.

Another benefit derived from the first group is that in multiplying
they may almost completely inhibit the aerobic and anrerobic spore-
bearing organisms present.

Boiling or heating milk affects the various groups in different ways.
At 60 degrees C. the lactic acid bacteria are destroyed, affording an
opportunity now for the development of the other group, and as these
groups develop gaseous putrefactive changes occur in the milk. At 85
degrees C. the first group — the lactic acid group — are entirely destroyed.
The aerobic spore-bearing organisms now appear in great profusion, con-
verting the curd produced by other organisms into a slimy liquid which
gives the disagreeable odor of putrefaction. This change is undesirable,
as the spores which cause it will survive even on ice for a long time. It
appears that to completely destroy these spores milk will have to be sub-
jected to the action of steam under pressure.

From these facts we are warned that there is a danger zone in heating
milk, ranging from 65 degrees to 85 degrees C. Between these figures it



40 NORTH CAROLINA MEDICAL SOCIETY.

will not clot normally, and undesirable changes take place as described
above. Hence it appears from investigations of Ford and Pryor,20 if
such antagonism exists in milk between the lactic acid group and the
spore-bearing aerobes and anaerobes, that a similar antagonism may be
found in the intestinal tract of man. If such is the case, the use of lactic
acid bacteria in intestinal derangements, due to the growth of spore-
bearing bacteria, is advisable, and the use of milk, in which the lactic
acid bacteria have been destroyed, without, at the same time, destroying
the si^ore-bearing bacteria, would seem to be contra-indicated.

The safest milk, when not sure of uncontamination with pathogenic
organisms, is milk that has been boiled from ten minutes to one-half hour
and then preserved on ice. Also, all heated or boiled milk should invari-
ably be kept on ice, since heated milk is more apt to be decomposed than
raw milk.

In any sort of a discussion of milk we must keep constantly before us
the importance of the metallic salts, in their phj^siologic functions as well
as in certain pathologic conditions. The production of thrombosis has
already been mentioned, and other phenomena, such as the retention of
sodium chloride, with the production of csdema, the part iron plays in
chlorosis, and many other abnormal conditions are now thought to be due
to. a deficiency of one or more of these salts. Recently the etiology of
chilblain, angio-neurotic oedema, urticaria, physiological albuminuria,
and certain forms of headache have been explained upon this basis.

Dogs fed on an ash-free diet of fats, carbohydrates, and meats die in
twenty-six to thirty-six days. Mice die in twenty to thirty days if fed
on the organic but ash-free constituents together with the extracted salts
of cow's milk. Hence Lunin in conducting his experiments on mice con-
cluded that the inorganic salts must be provided in organic combinations
as found in vegetable and animal food.

Following these experiments, it has further been determined that there
are certain organic substances present in milk and other foodstuffs in
minute quantities that have no doubt heretofore been overlooked. It
appears that they play a most important part both in growth and in dis-
ease. These organic substances would have been removed in the experi-
ments mentioned above on dogs and mice. To these important organic
substances the name vitamines has been given. One has been isolated in
the outer layer of rice and given the formula CLHoON^^i ^y Funk.-^
He has also found these bodies in milk, yeast, ox-brain, and lime juice.
A sterilization or boiling of milk appears to destroy the vitamine, so that
it probably explains the production of scurvy in infants fed entirely on
such milk. While some of the vitamines are destroyed by heat, as in



PHYSIOLOGY AND CHEMISTRY'. -41

milk and in dried fruit and vegetables, lime juice appears to be an excep-
tion. It does not lose its activity as an anti-scorbutic, after having been
boiled an hour. There are probably similar substances in meat extracts.
A knowledge of this may cause us to revise our estimate of the value of
bouillon and beef tea. Not because of their nutritional value, for it is
negligible, but for its well known action as a stimulant to gastric secre-
tion and the jirobable fact of its containing vitamines.

It appears, then, that the inorganic salts are necessary to maintain
life; that in all probability they are best absorbed and utilized when in
organic combination Avith foods; that there is a striking difference be-
tween the ash content of human and cow's milk, which should have
weight in the artificial feeding of infants; that certain pathologic con-
ditions arise when the organism is deprived of certain inorganic salts,
that is, they are not absorbed even though found in abundance in the
food; that in certain other pathologic conditions salts are actually with-
drawn from the body to such an extent as to impoverish the organisms
and produce grave disturbances of nutrition. - Also, that these salts are
present in human milk in sufficient quantity and in correct proportion
for the needs of the nursing infant. This fact holds true with the excep-
tion of iron.

In the case of iron we are struck with the relatively low iron content
of milk as compared with the content of the other salts. This same com-
parison holds true with many of our foodstuffs. Bunge in his analysis
of iron makes this clear. The values refer to 100 grams of substance
with iron in milligTams :

Sugar Rye .3.7 to 4.9

Egg albumen Cabbage 4.5

Honey 1.2 Potatoes 6.4

Rice lto2.5 Beans 8.3

Oranges 1.5 Beef 16.9

White bread 1.5 Asparagus 20.0

Apples 1.9 Egg yolk 10 to 24

Cow's milk 2..3 to 3.1 Spinach .33 to 39

Human milk 2.3 Hemoglobin .340 ■

Though human as well as other milk is poor in iron, yet it appears
that the mother supplies its young with a sufficient amount of iron. This
supply, however, is not furnished in the milk, but by way of the placenta.
This is corroborated by many analyses of animals and human embryos.
It is found in both that the iron content is greatest at birth and decreases
steadily until it reaches its minimum at the end of the period of lacta-
tion. Why such a mechanism is preferred, rather than have a sufficient



42 NORTH CAROLINA MEDICAL SOCIETY.

amount of iron secreted in the milk, is not clear. Yet an attempt to
explain sucli an occurrence would in all probability throw some light on
the absorption of iron in general.

Hemoglobin contains .4% of iron, yet it is estimated that the entire
blood of an average man contains only 2.5 grains of iron. - ^ So from
this we must understand that while hemoglobin is comparatively rich in
iron, it is nevertheless an extremely precious metal in the body. Indeed,
so scarce is this metal that nature conserves it in the organisms; for
when hemoglobin is destroyed in the liver the iron contained in the
hemoglobin is not excreted, but retained by the liver cells, and in all
probability used over again, in the red bone marrow, to help form fresh
hemoglobin for new red blood corpuscles. The pigments of bile, urine,
and feces contain no iron. It is to be remembered in this connection that
the capacity for hemoglobin to hold and convey the respiratory oxygen
depends directly upon the percentage of iron present.

This scarcity of iron in the body as well as in most foods, and the
uncertainty of its absorption through the alimentary canal, may be one
of the reasons for the economical handling of this element directly
through the placenta.

We must not lose sight of the import of iron. Besides, it should be
noted that the iron stored in the infant at first in sufficient quantity
decreases gradually from birth, and that towards the end of lactation the
store of iron in the infant plus the iron in the milk is insufficient for the
formation of the required amount of hemoglobin. This has been shown
to be true by excluding all foods except milk at the end of lactation,
when the infants invariably develop anemia. When foods rich in iron
are now administered to the anemic infant, the hemoglobin values in-
crease rapidly.

So it appears very undesirable that the child should be restricted to a
milk diet much longer than the ordinary period of lactation (nine
months), as after this time milk will not furnish the iron necessary for
the child.

The problem of iron absorption and its distribution in the body, when
inorganic iron is administered, has not been solved. • It is not yet known
whether the inorganic salts of iron take part in the formation of hemo-
globin or of hematin. While iron, in its inorganic form, will combat
chlorosis, and may be explained as forming hemoglobin, yet, on the other
hand, its effect may be indirect ; that is, only exciting those organs which
have to do with the formation of hemoglobin. We do not know as yet
whether chlorosis is actually caused by a lack of iron.



PHYSIOLOGY AND CHEMISTRY. 43

One fact in this connection should at least impress us. When inorganic
iron is added to milk and administered to an animal or child suiifering
from low hemoglobin content, it has no effect upon the absolute amount
of hemoglobin contained in the animal ; but, on the other hand, does
appear to accelerate the growth of the animal.

The difficulty of inorganic iron taking part in the formation of hemo-
globin can be shown by noting the structural formula for hemin and the
complex synthesis w^hich must take place if the animal cell is to utilize it.

The structural formula for hemin is introduced here merely to show
what a task the animal cell has to perform in the manufacture of this
substance from inorganic iron.

cm'm!v"c -c'UJ*^'^

NHCH^I |CH^ NH

Tea

CH^I tCHa

C H_c/\ h t^^—0 H

c hI'jijich- (OH) c yu'cH

NHCH^ CHJHN

The introduction of iron in this molecule is probably not difficult. It
is to be noted that iron does not play the important role in this formation
of hemin, but that there must be other organic material available. So in
a practical Avay, Avhen we think of inorganic iron participating by syn-
thesis in the formation of hemoglobin, it must be recalled that other
building material plays the important role in such a synthesis. The
application is to give foods (such as meats, eggs, and green vegetables)
which are rich in iron, and yet combined with other material necessary
for the formation of hemoglobin.

Other salts of milk which in one way or another influence the meta-
bolic process are magnesium, potassium, sodium, phosphorus, and sul-
phur. Potassium salts are essential to body growth. The potassium ion
acts in the reverse direction to the sodium ion, since it promotes muscular
relaxation. The sodium ion is essential in preserving the irritability of
tissue, especially muscle tissue. While both of these salts appear to be
essential, the former one (potassium) is usually supplied in sufficient
amounts with our food, and the latter (sodium) is generally added by
the cook. Magnesium salts appear to favor the inhibitory processes in
the body, acting as a probable antagonist to the calcium salts, which
appear to be activators. - ^



44 NORTH CAROLINA MEDICAL SOCIETY.

Phosphorus must be of much importance, especially during growth.
It is found in certain important compounds of the body, in nucleo-pro-
tein, nucleiu, nucleic acid, and the phosphatides — lecithin, kephalin, and
sphingomyelin, which occur for the most part in nerve tissue. It is an
important constituent of the human skeleton, and is present in milk,
partly in organic combination as in casein and partly as in inorganic
salt. There is a parallelism between phosphorus and the calcium con-
tent of milk and the rate of growth of the young of the species.

As Hutchinson points out that the brain of the new-born infant is
doubled in weight during lactation, and as we have already seen phos-
phorus is an important element in its building, to say nothing of the
skeleton, we can easily realize its import.

The amount of phosphoric acid in human milk is 0.05% per hundred
parts by weight of milk. In cow's milk there is 0.20% per hundred
parts; in rabbit's milk there is 0.99% per hundred parts. While the
human milk contains the least, yet it appears sufficient for a proper
development. This comparison of human, cow's, and rabbit's milk shows
how difficult it is to replace one kind of milk with that of another when
we take in consideration the wide difference in rate of groAvth as well as
in the composition of the milk itself.

While the law of the minimum should hold in regard to the inorganic
elements, yet we should not lose sight of the fact that though a milk sub-
stitute be rich in an element like phosphorus, it may be of little value ;
for in order that the cells may utilize phosphorus it is necessary for suf-
ficient amounts of certain other substances to be present, as pointed out
in the discussion of iron.

There is no doubt that in most of the dilutions of cow's milk there is
an excess of certain inorganic salts, a fact now neglected in the feeding
or normal infants. On the other hand, their presence may play an
equally important role in the feeding of children already suffering from
a disturbance of nutrition. This lack of the knowledge of the inorganic
salts and the role they play in metabolism is in all probability one of the
factors that account for a greater mortalitv in bottle-fed babies.



BIBLIOGRAPHY.

'Hawk, P. B., Phys. Chem., 4th Ed., 235, 1912.

=Jones, H. N., Jour. Infectious Diseases, 15-357, 1014.

^IMd., 1.

*Brown, Langdon, Physiological Principles in Treatment, 3d Ed., 374, 1914.

=Lyle, H. W., Manual of Phys., 412, 1911.

^Martin, ibid., 5.

"Abderhalden, Emil. Phys. Chem., 3G8. 1908.

»IMd., 7, 370.

"Bunge, G. von, Z. Biol., 45-532, 1901.



PHYSIOLOGY AND CHEMISTRY. 45

i»Boswerth, A. W., Jour. Biol. Chem.. 20-24-727, 1015.

"Vaudin, L., Am. Inst. Pasteur, 8-502, 1894.

'-Kerley, C. G., Treat. Dis. Child.. 2 Ed.. 465. 1909.

i3Jour. A. M. A., Ed., 200, 1913.

"Schafer, Text-book Phys., vol. 1, 126.

i-'Clark, W. M., Jour. Med. Research, vol. 31, No. 3, 431, 1914.

'"Courant. ihkl., 14.

^Uhid., 14.

^"■IbiiL, 14.

"Ford, W. W., and Pryor, J. C, Johns Hopkins Bulletin. 25. 270, 1914.

-oibUL, 19.

-'Brown, Phjs. Princ. Treat., 367, 1914.

"Hoobler, B. R., Amer. Jour. Dls. Child., 2-107, 1911.

"■^Lyle, H. W., Manual of Phys., 264.

=*Xecki, M. and Zaleskl, J., in Abderhalden Phys. Chem., 396. 1908.

Dr. L. B. Morse, Hendersonville : In regard to the reading of the
papers on our program, we have somewhere in the neighborhood of one
hundred papers. I have every reason to know and believe that the
paper we have just heard is probably a most scientific one ; but the time
consumed is very great, and it is a question of getting through the
program. If we devoted as much time to every paper as we have to
this one, we should be here for three weeks.

The most successful medical meeting I ever attended Avas in Charles-
ton, S. C, about four years ago, and I want to tell you how it came to
be so successful. When the gentleman who was president at that time
accepted that office, he did so with the provision that he might put in
operation certain rules. Those rules were something like this : That



Online LibraryMedical Society of the State of North Carolina. AnTransactions of the Medical Society of the State of North Carolina [serial] (Volume 62 (1915)) → online text (page 6 of 58)