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CHEMICAL AND PHYSICAL ANALYSIS

Mick, ConpENSED MILK.

INFANTS’ MILK-FOODS,

WITH SPECIAL REGARD TO

HYGIENE AND SANITARY MILK INSPECTION.

A Laboratory Guide, developed from Practical Experience,
INTENDED FOR

age

CHEMISTS, PHYSICIANS, SANITARIANS, STUDENTS, ETC.”

By Dr. NICHOLAS GERBER,

Manager of the American-Swiss Milk Product Company (Limited) in New York; Member of the

Chemical Societies of Berlin, New York, Paris, etc.

Translated from the Revised German Edition, and Edited by

Dr. HERMANN ENDEMANN,

Editor of the Journal of the American Chemical Society ; Member of the Chemical Societies of

Berlin, New York, etc., etc.

ILLUSTRATED BY 19 PLATES,

New York, 1882.

Entered according to Act of Congress, in the year 1882, by the proprietors,
Dr. NICHOLAS GERBER, of Little Falls, N. Y.,
Dr. HERMANN ENDEMANN, of 33 Nassau St., New York City,
OF.cof > 7 strict +1 of the Uni. s-forthe Southe

aaa Dis'1ict of New York.

LEHMAIER & BRO, PRINT,
95, 97, FULTON STREET, N. Y.

me

EDITOR’S PREFACE.

In preparing this book for the English-speaking public, the
undersigned desires to state that he has undertaken this task for
the purpose of supplying a long-felt want. Most books published
of late contain merely a collection of all the methods of analysis,
or the selection of a number, put side by side without criticism.

The book in its present shape is a laboratory guide, which
enables even beginners, and all such who cannot make the subject
of milk analysis a speciality, to cope with this otherwise compli-
cated task.

The selection of the proper method of analysis is taken off
their hands and has been supplied by a man of practical experi-
ence, who has for many years made this subject a specialty.

Even chemists will find this book valuable, the more so as they
are the best able to judge the advantages derived from the proper
selection of the method adapted for the execution of an analysis.

The original has been carefully revised and many of ,the
plates which illustrate the work have been substituted by better
ones taken from the best publications on this subject, while others

not contained in the original have been added.

H. ENDEMANN, Ph.D.

New York City, January, 1882.

PREFACE.

The undersigned has been engaged, scientifically and practically,
in the dairy industry in all its branches for a number of years, and
thus has had, frequently, occasion to seriously feel the want of a
uniform method of analysis for milk and its products, which would
not only satisfy practical wants, but would also possess scientific
accuracy.

The author has made it his task to present in this small volume
a short and exact method of analysis for the examination of the
various milks and infants’ milk foods, and hopes to soon complete
his undertaking by the issue of a similar volume which shall com-
prise the examination of the other milk products and such other
substances as are employed in the dairy industry.

As inay be seen by the contents, undersigned has not endeav-
ored to criticise the various older methods, as yet generally in use,
as this wonld have been beyond the range of his self-imposed task.

Moreover, there is no want of such books. Undersigned
therefore refers to those previously published by Vieth, Raden-
hausen and himself.

It is a peculiar fact, that even in the latest chemical, medical
and pharmaceutical works, old and abandoned methods are con-
tinually republished, the authors considering it apparently unnec-
essary to test them for their reliability.

Likewise, in the adducing of average figures regarding the
composition of milk, these authors seem to be prepossessed in
favor of the oldest and least exact investigations, while they
neglect the more exact and, therefore, more valuable examinations
of the present period.

vi

This copying without examination (book manufacturing) is
especially dangerous in analytical chemistry, and more so if the
results must stand test before a court of justice, which in examina-
tions of this kind is frequently required.

The position of an expert who has employed acknowledged
inaccurate methods for his examination, is certainly not an envia-
ble one.

The author of this small volume has therefore collected therein,
for the first time, those methods which are acknowledged as being
the best for scientific and practical purposes.

They excel the methods known before 1877.

Ist. For their greater accuracy.

2d. For greater simplicity.

3d. For cheapness and economy of time.

The views expressed in this book no doubt may be modified in
time, and undersigned will, therefore, at all times, be pleased to
receive suggestions from others.

Dr. NICHOLAS GERBER,
Manager of the American Swiss Milk Product Co, (Limited),
New York City.

\

Lirtte Fauzs, N. Y., January, 1882.

CONTENTS.

Introduction............cce cece 1
NORMAL COWS’ MILK.
General Definition................ 3
Colostr ames: ors ses cesarean need 3
Market Milk... ...........0..00005 3

Physiological and Other Causes
Influencing the Secretion.

Period of Lactation............... 3
Ageiol COW vi ssiseciemsreswiawoae aes 4
Cows in Heats ic ssccsivccases seas 4
Race and Individuality............ 4
Food and Treatment.............. 5
MCAS OWS) 5-4-5). c.ardsarkuivarerciaualla ouaeve glare 2.0% 5
Influence of Temperature.......... 5
Influence of Weather.............. 5
TUX CL CISE sieisjseiavais ees 45 ¥'ale 4 gis nity ere ee 5
General Physical Properties. ......+. 6
Chemical Constituents... ...0cec0ers 6
Composition of other Milk Compared
with Cows Milk. ccocercceveveee 8
PHYSICAL ANALYSIS OF
MILK.
Color—Normal..........eee ee eeeee 9
FRE Goi. 532 564 aas sitet tocatesaesascsvanus ¢ 9
WellOwig.icen age atadaaniis , 10
BGs aciets atten: Glavine 10
Consistency—Normal..........2055 11
Waateryics cons cvesaces 11
Colostrum...... ..... 11
Phlegmy and Stringy.. 12
DANDY ceisidiesaiscod tony esa 12
Odor—Normal....... cceeceeeeeee 13
ATOMALNGS « sie siden aes sees 13
Putrid nscssawse ia! ss mecrrnnce 13
Medicinal............-..... 13
Taste—Normal... 1... .sssecceees 13
Bitten coer ave-nensaccete «ways ereee 14
Medicinal.............2+6. 14
Putrid... 06 vossanniews sys ee 14

Microscopical Examination.

1 PAGE.
Normal Milk (with plate).......-.. 14
Butter Globules....... .......-085 14
Colostrum (with plate)............ 15

Pus and Epithelial Cells (with plate). ae
Lower Organisms...............5.
Specific Cravity.
DGRNUIOW si pesca weaee ales ts ease
Apparatus for Its Determination...
Weighing in a Flask (Pycnometer)

(with table.). «sos cncn0s carveses 18
CHEMICAL ANALYSIS OF
MILK.

General Rules...............00--- 21
Reaction of Milk.... ...........4- 22
Determination of Water and Solids. 22
Determination of Ashes........... 23

Determination of Phosphoric Acid. 23

Determination of Albuminates and
Fat (with plate).............08. 24
Determination of Milk Sugar...... 27

ABNORMAL COWS’ MILK.
COLDS UTI Titec aces aos br as eh a eo i eis 30
Poisoned Miles os. gas iviccascanicogsens 31
Milk Containing Medicines......... 33
Milk as the Cause of Disase (2 plates) 33
Ty Phuss <0 95 <é ap4 8300 view views 34
Scarlatinial. siidscceeaiisen iscisee cen’ 34
Tuberculosis.........00cee0e0e 34
ATHDTAR oie ges gate ose ting vig 35
Aphtha epizootica (with plate) 35
Influence of Food, tte. .cceeveverene 37
Potato Distillery Swill......... 37
Brewers’ Grains ...........00 38
Milk in Fermentation ......... 38
US seat cance, 8s sages <eiaeees 38
MUCUS wire vind ssc dia eanrren 38
Adulteration of Cows’ Milk....6..5. 38
Watery Milk ................. 39
Normal Market Milk.......... 40
Sour Miles vaeeaisiee omnes 41
Foreign Substances............ 41
Preservatives........ -Sahd ares 42

vili

MILK OF OTHER ANIMALS.

PAGE.

Goats’ Milk ......... 0... eee 44

Sheep’s Milk ..............0.. 44

Asses’ Milk........ aeianavost aint sd 45

Mares’ Milk sccsse sowes oer ees 45

CONDENSEDAND PRESERVED
MILKS.

Condensed Milk, with Sugar........ 47
Physical Analysis ............. 48
Chemical Analysis............ 49

Other Milk, Preserves.cccccccevseeee 50
Hygienic Demands............ 51

WOMAN'S MILK.

Various Influences upon the Se-
CTEMONssiee Seca y eee een as
Taking the Sample............ 55
Physical Examination (2 plates) 55
Chemical Analysis............ 57
Milk from the Breasts of Newly-born

TRPONES 2 Rae RE LNs see SRO HE SA 60
INFANTS’ MILK FOODS IN
POWDER.

History, Definition............ 61
Physical Properties............ 61

Microscopical Examination (5 plates). 62

Chemical Analysts...ccicccecccsvees 65
Determination of Water....... 65

ie of Ash and Phos-
phoric Reid iiartesineiere Ne nae 66
Determination of Fat ......... 66

" of Soluble Car-
bohydrates ........ cee eeeee 67

Determination of Insoluble Car-
bohydrates........sc.s eee 68

Determination of Albuminates. 69
Reports on Milk Foods........ 69

Inrants’ Mik Foops 1n Powper--Continued.
PAGE.

Hygienic Demands of the Manufac-
turers

GOVERNMENT CONTROL OF
THE MILK SUPPLY........ 73
Determination of Specific Gravity.... 76
Quevenne’s Lactodensimeter and
the Lactometer (2 plates)..... 78
And 2 tables............ 81 and 82
Examination of Skimmed Milk 838
Stable Test.... ...c.csse cee 84
Estimation of the Quality of
Milk by the specific gravity... 85
Determination of the Fat
(with plate and table)............
Properties of Normal Cows’
Milk and Market Miltk.....
The Aim of Governmental
Control of the Quality of
the Milk Supply............
General Rules for a Rational

Milk Inspection............. 94
In, Cities: ....c.caw ovaes ae 3 we aro 94
In the Stable...............0.. 96

Proposition stating the Main
Points for an Ordinance
Regulating the Sale of
Milk in Large Cities.......

Propositions for Regulations
Governing Producers of
Milk and Milk Dealers...... 98

LIST OF APPARATUS AND
CHEMICALS REQUIRED
FOR THE ANALYSIS OF
MILK and INFANTS’ MILK

INTRODUCTION.

Or all articles of food, none requires so much of our attention as
milk. While it engages the scientist on account of its relation to
physiology and pathology, the public are interested in milk by
the place it occupies as a food of so general application, and by
the fact that it forms an important article of commerce and a base
for manifold industries. Cows’ milk, and of late, infants’ milk-foods
and condensed milk, are of more special interest by the fact, that in
the case of an insufficient or wholly wanting supply of breast milk,
they are destined to form, for a considerable period of time, the
sole food for infants. We should, therefore, be well acquainted
with the quality of these articles as they reach the consumer.

To insure a supply of healthy and unadulterated food, the gov-
ernments of many countries have passed laws for the punishment
of adulterations, and in order to detect them, have taken the ex-
amination of the various food substances in hand. Milk, being
more exposed to adulteration than many other foods, has of late re-
ceived a considerable share of this attention.

The control which a government exerts, protects the public
against fraud by preventing the sale of goods of inferior value at
high prices; but more important is the protection which, by gov-
ernment interference, is gained for the health of the consumer by
the absolute prevention of the sale of specifically altered, spoiled
and adulterated milk. The poorer and working classes, and espec-
ially the children, suffer most, if the milk is not of the best
quality.

Chemical analysis, even if carried out according to the best ap- _
proved methods, would not bring us nearer to a satisfactory solu-
tion of this question, unless exact science has thoroughly investi-

2

gated this field, and has, based upon such investigation, determined
the limits of the composition of a normal food. Without this, the
position of an expert before a court of justice would be untenable.

The examination of the milk differs according to the question
which is to be decided. It may be made to ascertain the relative
quantities of the normal constituents of milk, or to determine the
admixture and nature of foreign substances which may, or may not,
be dangerous to the health of the consumers.

Each chemical examination is preceded by an examination with
the senses—eye, smell and taste. Hereby many admixtures and
qualities of milk may be directly ascertained, which, for the fol-
lowing chemical examination, may not only furnish hints, but
which may serve to corroborate the results obtained by it.

The physiological part of the milk question has been included
for the reason that in cases before the courts such questions fre-
quently arise, and because the knowledge of them will aid in the
formation of a more correct opinion.

To facilitate the examination of milk and milk products, a num-
ber of plates from microscopic objects have been introduced into
the text.

The chemical and physical analysis of infants’ milk-foods and
their hygienic value, has in no previous work been treated as
thoroughly. The method of analysis given is based upon the exact
investigations made by Dr. P. Radenhausen and the author, and is
given in this work in an improved shape. The author desires to
recommend to the consideration of the medical profession the
chapter entitled, “ Hygienic demands upon the manufacturers of
infants’ milk-foods.” Humanity demands that we know and ex-
amine which foods should be recommended and can be relied upon.
Much hardship and sickness of mankind can be prevented, if by
rational food the organism, especially of infants, be strengthened.
The author sincerely desires that the contents of this book will not
fail to improve our knowledge of food hygiene, and thus fulfil the
expectations, with which it has been written.

NORMAL COWS’ MILK.
GENERAL DEFINITION.

Mix is the secretion of the mammary glands, in which it is
produced by certain processes of diffusion from the blood, accom-
panied by a dissolution of the gland cells. Lactation commences a
few days after birth, and lasts for a period of time, the length of
which depends on various circumstances. C. Von Voit says:
“Milk consists of liquified cells. All mammals are, therefore,
carnivore, for they sustain themselves by consuming a portion of
the body of their mother.”

Colostrum: The first milk yielded by a cow, either before, or
from the fourth to seventh day after calving, is called ‘beastings,’
or ‘colostrum.’

Market milk is generally the milk of several cows mixed. For
the examination of the milk, as it reaches our markets, this is
a point of great importance—many irregularities, frequently met
with in the milk of single cows, being thereby compensated.

The substances composing milk are for all mammals essentially
the same. So is the general character of the milks. The differ-
ence of the various milks consists, therefore, only in the respective
quantities in which the constituents are present, as also in taste,
flavor and color.

Physiological and other Causes Influencing
the Secretion.

The period of lactation generally lasts three hundred days,
one cow giving during this time from six to ten quarts of milk
per day. When the animal ceases to give milk, we say that it
stands dry.

4

The following circumstances are of influence on lactation :

Age of cow: When a cow has its first calf, it does not pro-
duce the maximum quantity of milk, but the quantity increases
from year to year until a certain limit is reached, when, with fur-
ther increasing age, the quantity is reduced, at first slowly and
more quickly later on.

The age to which it pays to keep cows for milking differs
according to individuality, race and treatment. It is generally
accepted that cows are the most profitable from their third to their
tenth year.

Cows in heat: We know but little of the changes which oc-
cur in milk at the return of the periods when cows get in heat.

From the feeding experiments made by G. Kuehn and Fleischer,
a characteristic change of the milk, during these periods, cannot be
deduced. Such milk, it has been stated, will sometimes curdle on
boiling. A normal course of this process, which lasts but a few
days, should not influence normal lactation for any length of time.

It may be remarked that also cows which have undergone the
process of castration, may produce milk. It is, however, not con-
sidered profitable to keep such cows longer than two years. They
fatten up rapidly, and their milk-producing qualities suffer in con-
sequence.

Race and individuality: Good milk-producing qualities de-
pend principally on a strong and healthy development of the udder.
A defect in this can never be remedied by the best and most
nutritious food. The yield and quality of the milk depends directly
on individual properties of the animal and, therefore, also on its
race.

Comparative investigations regarding the yield and quality of
the milk of different races have frequently been made, but they are
incomplete and little trustworthy. They have either been under-
taken with but few animals for a longer period, or if really on a
large scale, but for a short period. In some cases select stock has
been observed for longer periods. Average figures deduced from
such incomplete and heterogeneous observations are, therefore, of
little value. The yield and quality of the milk of various races and
breeds of cattle, cannot be determined without the collection of
copious and well selected statistics in the countries of which these
cattle are indigenous. Few investigations have been made to
which chemistry has contributed as largely as it should have done.

5

Food and treatment: To keep the production of milk dur-
ing the whole period of lactation in a satisfactory state, good
housing and treatment, and food answering the circumstances, as
regards quantity, volume, preparation and chemical composition,
are requisite.

It may be regarded as a fact, that the quantities of milk and
butter are increased with the amount of nitrogenous material in
the food. Uniformity of treatment and food are to be recom-
mended, and sudden changes in this regard be avoided, since ex-
perience has proved that they are invariably followed by disadvan-
tageous influences upon the secretion of milk. The production of
milk is greatly fostered by healthy water of an even temperature,
neither too high nor too low, charitable treatment of the cattle, and
punctuality in attending to their wants.

Seasons: The yield of milk differs with the changes of weather
and food in the several seasons. Most, but often also thinnest,
milk is produced during the spring, on account of the food which
then consists mainly of young luxurious herbs. The more nourish-
ing after-growths on the meadows and fields during summer and
fall, as also the dry food during winter, are the cause of a smaller
yield of milk which, however, is richer.

Influence of temperature: The yield of milk of the cows
differs with the geographical latitude. From this alone we may
assume that the temperature exerts a decided influence. An aver-
age annual temperature of 15° C. is considered to be the most ad-
vantageous. Too high temperatures (in the stable) debilitate and
predispose the cows to colds, influence disadvantageously the yield
of milk, and sometimes even its quality.

Influence of weather: Rain, humidity of air and winds doubt-
less exert an influence on the general well-being and the various
physiological processes. Exact investigations as regards the in-
fluence of these meteorological phenomena on yield and quality of
milk, have not yet been made.

Exercise: Moderate exercise in the open air and on the pas-
ture is advisable. Hard work and long journeys diminish yield
and quality of milk. Milk of such cows is apt to curdle on
boiling.

The constitution of the animal is reproduced in the milk it
yields. The milk of stronger animals is, therefore, on the average,

6

richer than the milk from the weaker. The use of inferior food
and unhealthy water, and certain diseases, cause dlso the produc-
tion of an inferior milk. Particulars regarding this will be given
in the chapter on “ Abnormal cows’ milk.”

General Physical Properties.

Milk is an opaque, white or more or less yellowish fluid. Be-
tween the fingers it feels greasy. It has a weak, mild, sweetish
taste, and flavor to correspond. The microscope reveals the
presence of innumerable small ylobules suspended in a pelucid fluid.
Sometimes epithelial cells, gland cells and lower organisms may
be recognized. The specific gravity varies from 1.025 to 1.038.

Chemical Constituents.

I. The main constituent of milk is water, of which, on the
average, 87.5 per cent. is present.

II. The albuminutes of milk are, according to the latest inves-
tigations of Danilewsky and Radenhausen, as follows:

1. Atsumen, probably identical with blood albumen.

2. ProraLzumens, which Danilewsky obtained some time since
by peptonizing various albuminates with alkali and pan-
creatine. These give to casein its acid character. Albu-
men and the protalbumens together form the so-called
casein, which is, therefore, not a single body but a mix-
ture.

38. Orroproretn, which is an albumen with albuminoid char-
acteristics.

4, Synro-PROTALBUMENS, which, according to Danilewsky, are
obtained from albuminates by the action of acids and
pepsin.

5. Prrrones, or digested albuminates, were found by D. and
R. in the serum of coagulated milk, together with the ex-
tractive substances.

Milk contains, therefore, according to Danilewsky and
Radenhausen, large quantities of incompletely digested
albuminates which, according to their characteristics,
were called protalbumens and synto-protalbumens.

7

The protalbumens are acid bodies, soluble in 50 per
cent. alcohol, insoluble or little soluble in water. At
ordinary temperature they saturate alkalies but not acids.

The synto-protalbumens have a neutral reaction. At
ordinary temperature they do not unite with alkalies,
but mineral acids. They act, therefore, as bases. They
are insoluble in water, soluble in hot 50 per cent. al-
cohol, from which solution they may be obtained on
cooling. The main constituent of the albwmen of former
investigation, is identical with the stroma albumen which
envelopes the butter globules.

These investigations give us an entirely new picture
of the constitution of milk. The hitherto known casein,
albumen and lacto-protein, do not exist, and these names
should, therefore, not be used in reporting the results of
the analysis ; instead, it is better to class them under the
general denomination of “ albuminates.”

IIL, The mitk-fats appear as minute globules which can be re-
cognized merely with the aid of the microscope. Each of these
globules is surrounded by a thin film of stroma albumen (not ca-
sein). Their diameter varies considerably. Specific gravity and
melting point vary likewise with race and quality.

The fats are triglycerides, derived mainly from stearic, pal-
mitinic and oleic acids ; aside from these the following are to be
mentioned: myristine, butine, butyrine, capronine and capryline.
The chemical composition varies considerably with the food on
which the animal is kept, likewise the color, which, during the sum-
mer is yellow, while during the winter it appears more white.
Fresh milk-fat is a semi-fluid mass of faint taste and odor.

IV. Milk sugar (C,,H.,0, + H,O) crystallizes when pure in
rhombic prisms, which are not changed when keptin dry air. It
feels hard and gritty between the teeth. It is insoluble in absolute
alcohol and ether, soluble in 6 pts. of cold, and 2.5 pts. of boiling
water. Its taste is only slightly sweet. Its specific gravity varies
from 1.543 to 1.548. In the polariscope it shows birotation.

8

V. The Milk ashes consist, according to Fleischmann, in the
average, of

Phosphorie anhydride, ee OF catdasptwenncee 28.31
Chlorine, (Chee ova ewadisas sect 16.34
Lime, WOO ce seaeines 97.00
Potassa, (TOV irsvccaca scccuinin ge 17.34
Soda, En ©) Seen eee 10.00
Magnesia, (MBO) anamnde wean 4.07
Iron sesquioxide, (BeOS) niece stern ieee 0.62 -
108.68

Deduct for O corresponding Cl, 3.68
100.00

The quantity of salts in the milk ranges from 0.4 to 0.8 per
cent. They contain generally all those nutritive salts which have
been taken with the food.

VI. The gases of milk are carbon-dioxide, nitrogen and
oxygen, the first predominating. They are of little importance.

VII. The extractive substances: They have been found in
small quantities in the milk, and include the following substances :
urea, kreatinine, leucine, tyrosine and lecithine.

VIII. Insmall quantities, coloring substances, and such which
give to milk its characteristic flavor. They vary with the season
and food, and are met with in larger quantities during the summer
season.

Composition of Other Milks compared

with Cows’ Milk.

Milks from other animals differ from cows’ milk in composition
according to the position occupied by the animals in the zoological
system, and according to their food (her bivora or carnivora).

The following tabulated statement gives average values derived
from a series of exact analyses of normal milks:

Species. Sp. gr. Water. Salts. Albumen. Fat. Sugar

of Milk.

White woman....... 1.025-1.035 88-90 0.20-0.50 2.0-4.0 2.0-4.0 4.0-6.0
Negro ‘“‘_ ....... 1.025-1.037 86-90 0.30-0.75 3.0-4.0 4.0-5.0 5.0-6.0
Milk of single cows.. 1.025-1.0388 86-89 0.50-0.75 38.5-5.0 3.0-4.5 3.5-5.0
Mare sx savsarnsisie.s isis 1.031-1.036 90-92.5 0.25-0.50 1.5-8.0 0.5-1.5 4.5-6.5
ASB ies diss oa sore tiline 1.030-1.036 89-92 0.25-0.50 1.5-8.0 1.0-2.5 4.5-6.0
Goats «is cssesd vers 1.028-1.086 85-87 0.50-0.75 4.0-6.0 3.5-5.0 3.5-5.5
Sheep icccasasorsewns 1.084-1.042 80-85 . 0.50-1.25 4.0-6.5 4.0-7.0 4.0-6.0
OB aeitse aon nuanaies 82-85 0.75-1.25 5.0-7.0 5.5-7.0 2.0-5.0
CMe)... vsicnieie sents aie 1.085-1.042 85-87 0.50-0.75 38.0-4.0 2.5-8.5 5.0-6.5

Of the milk of other animals only a few, and then often incom-
plete analyses of doubtful value could be found; their mention
has therefore been omitted.

9

Physical Analysis of Milk.
COLOR.

Normat: Milk in its normal state is opaque white to yellow.
During winter it is more white, while in summer the color is more
or less yellow, produced by the richness of the food in chloro-
phyll. Plants containing certain coloring substances, may impart
certain hues to the color of milk. Peculiarities of color may, how-
ever, be produced by other causes.

Red: Red milk is mainly caused by a general diseasea condition
of the cow, and has been found in cases of anthrax, as an accom-
panying symptom of red murrain, and after the use of acrid and
resinous remedies.

Such milk contains many blood corpuscles and gives on standing,
a sediment. .

Milk appears sometimes irregularly colored, the color appearing
in streaks or attached to coagulated masses, which collect rapidly
at the bottom of the vessels. The occurrence of such milk is fre-
quently confined to certain parts of the udder, and is then caused
by congestion, inflammation, and mechanical injuries inflicted upon
the udder.

Detection: Blood corpuscles are easily detected by the micro-
scope. They are recognized by their yellowish color and their
shape. They present themselves as small disks, slightly indented
in the centre. This can best be seen on single corpuscles. They
are frequently united, forming bodies similar to rolls of specie.
The accompanying cut represents milk containing blood corpuscles.

10

Milk containing blood will, on boiling, change its color from red
to brown, since hemoglobine is decomposed on the application of
heat. Rennet and madder will color milk uniformly, and the color
thus produced does not undergo change on boiling.

Yellow: The yellow color may be produced by certain vegetable
pigments. It is said to also accompany certain changes which are
characterized by the formation of stringy, skinny and lumpy
coagula, which sink to the bottom on standing. The supernatant
milk appears opalescent and stringy. This color is also observed
in jaundice. Cause: congestion and inflammation of the udder.

Blue: A blue color in milk has rarely been observed at the
time of milking, unless it be produced by blue vegetable pigments.
The milk is in this case uniformly colored. Milk may, however,
after some time turn blue under the influence of certain ferments.
On the surface of the milk or the cream, beautiful indigo-blue
spots appear which gradually enlarge. After some time the color
ceases to increase, and then, even with the naked eye, the growth
of fungi can be observed. Already long before this the micro-
scope shows the presence of mycelium, vibrios and bacteria in such
milk. The original cause of this milk infection has been traced to
the growth of a certain fungus described by Fuerstenberg (see cut),
whereby the constituents of the milk are decomposed, giving rise,
as some believe, to the formation of aniline blue (triphenyl-
Tosaniline).

11

This has as yet not been established as a certainty. Spectro-
scopic investigations, however, point to a dye-stuff standing in near
relation to the aniline dyes. When and why this fungus makes its
appearance is not known. This milk disease.can be banished by
extreme cleanliness and the use of disinfectants.

As to the duration, appearance and propagation of this ab-
normity in one place, or in comparison with other places, no rules
could be established. It has likewise been found that the use of
preventatives was not always followed by the same results.

It is therefore easily understood why so many theories as to its
cause should be given. While one looks for the cause to the cow,
others find it in the food, until we know now that this abnormity
is produced by a ferment. (Peterson, Horschungen, 1881, p. 78.)

CONSISTENCY.

Normal milk: Normal whole milk is a fatty, homogeneous,
opaque liquid, which is always heavier than water. Its consistency
is influenced by the milking, the first milk being always more
watery than the last. This circumstance is of considerable im-
portance when an examination is to be made of the milk furnished
by a certain animal, or all such as are housed together or supply a
dairy. The following abnormal conditions have been observed :

Watery mitk: Watery milk is strikingly fluid and of a bluish-
white color. It is poor in solids, especially fat, and its specific
gravity is below the normal.

Causes: Indigestion, unsuitable food and housing. Indigestion
may be cansed by the animal getting in heat. This normal exist-
ence of watery milk must be well considered in milk inspection.
It will rarely affect more than a few cows in the same stable at one
time, and if such milk is mixed with the normal milk of the other
cows, its characteristics, notably its low specific gravity, will be
compensated. It can therefore but rarely be the cause of serious
complaints.

Colostrum ; Colostrum, by milkmen and farmers called beast-
ings, is decidedly phlegmy and glutinous. It possesses a peculiar
stale taste. On boiling, it curdles. Its specitic gravity is very
high=1.08, it being very rich in solids. This milk is not an
article of trade.

12 f

Phlegmy and stringy mitk shows its characteristics only some
time after milking. It is thick and of flat taste, and shows its
stringy consistency if it is observed while it runs from the finger
after immersion. It creams slowly, and it is difficult to obtain
butter from it, which, when obtained, has a disagreeable taste.
Investigations regarding this process are incomplete, but it seems
that it is produced by some process of fermentation. Phlegmy
milk is said to curdle sooner than normal milk, the curd presenting
likewise an abnormal appearance and phlegmy consistency.

Such milk is said to infect normal milk. Its occurrence is caused
by indigestion, the use of poor and spoiled food, colds, and, accord-
ing to the latest investigations, also inefficient ventilation of the
dairies.

In Norway, Sweden and Finland, an herb, Penguicula vulgaris,
is added to the milk as a preservative. It is known to make milk
likewise stringy.

Sandy milk: Sandy milk contains solid mineral granules,
which are often so large and occur in such quantities, that the teats
become clogged.

Fuerstenberg, who examined such milks very thoroughly, distin-
guishes three kinds of milk stones or galactites.

1. Reat earactires consist of small granules, around which
amorphous salts of the alkaline earths have formed in concentric
layers. They are in shape globular, elongated, and occasionally
angular. Their surface is either smooth or rough, and their color
whitish to gray. In size they range from the size of a millet grain
to the size of a bean.

2. Psrupo GALACTITEs are in appearance similar to the former ;
they consist, however, of a hollow and compact curd of casein,
which is covered with crusts of salt.

3. ConcREMENTS are amorphous, comparatively large, irregularly
shaped masses of organic matter, without concentric structure.
Their surfaces are rough white and lustreless like chalk. When
brought in water they swell and become soft.

Cause: Food and water, rich in salts of the alkaline earths, es-
pecially lime.

13

Chemical composition, according to Fuerstenberg :

GALACTITES.
Real. Pseudo. Concre-
ments,
Calcium carbonate.............. 91.038 92.80 17.45

Phosphates of alkaline earths.... 1.13 2.78 55.98

Rice sg aap le — oped eh 1.30 0.93 2.60
Other organic substances...... 5.40 3.14 18.55
WaletG ina) sores eusermemin wveds’ L114 0,85 * 5.88
Specie gravity... .cccsveess es 2.192 2.281 2.114

ODOR.

Normal; Milk possesses a peculiar odor, especially at the
time when it comes from the udder.

This is similar to the exhalation of the skin, and must not be
confounded with the milk flavor or aroma. It seems to be a pe-
culiar substance, and not to belong to one of the recognized con-
stituents of milk.

Milk filtered over animal charcoal ‘is said to lose this smell.
It is therefore considered a substance for itself.

This animal odor is stronger during the heat of summer than
in winter time, and is apt, if present in quantity, to adhere even to
the preparations manufactured from milk. Milk should, there-
fore, be frequently aired to free it from this odor.:

Aromatic: The essential oils of certain herbs contained in the
food are also easily recognized by the peculiar flavor which they
impart to milk.

Putrid: Putrid decomposition of milk has been observed as
consequence of untidy handling, keeping, and feeding with tainted
food and crude rancid bone dust, which at one time had been re-
commended as tending to increase the yield of milk. The cream
of such milk is off-color, and breaks, in consequence of ascending
gas, which contains sulphuretted hydrogen.

Medicinal odor:. An abnormal odor in milk may also be
caused by the odor of substances contained in food or medicines.

TASTE.

Normat: Normal milk has a mild, sweetish taste. That cows’
milk does not taste like goats’ milk, is owing to the peculiar odor
which is observed when it is tasted.

14

Bitter: Bitter milk developes its taste only some time after it
was milked, and is accompanied by souring. The chemical changes
which take place in such milk are not known, but the development
of gas seems to indicate a fermentation, the whole being, perhaps,
merely an incipient state of putrid decomposition.

Milk is said to become bitter also after the feeding with bitter
herbs, like absynthum.

Medicinal: Medicines may likewise impart to milk a pe-
culiar taste.

Putrid: The taste of milk in putrid fermentation.

Sour: Milk sours most frequently in sultry weather during
the summer. It may also be caused by diseases of the udder, or
when the cows have not been completely milked. Such milk cur-
dles when heated.

The Microscopical Examination.

This examination is to determine qualitatively whether a milk
is normal, diseased, or partially adulterated. For the construction
and use of the microscope we must refer to such works as treat
this branch of science as a specialty.

Normal milk: Milk, like blood, is an emulsion containing
some substances in solution, while others, the so-called milk globules,
are held in suspension, thus producing the color and opacity pe-
culiar to milk.

Butter globules: The butter or milk globules are highly re-
fracting globules, with an average diameter of 0.017 to 0.025 m.m.

15

They appear with well marked outlines, dark at the edges, and
bright in the centre. They are simply fat globules which are pre-
vented from uniting by being immersed in milk plasma, which con-
tains casein in a swelled state. We distinguish three sizes of glob-
ules.

1. The very large, and comparatively lightest, which, on ac-
count of their larger volume, rise first, and form the first cream
on the milk. They are said to contain the fats of lowest melting
points.

2. The mediwm size form the main constituent of a good milk.

3. The smallest, of which good milk contains but few, and
poor milk large quantities.

White milk contains more of these butter globules than blue
milk.

A normal milk should contain these globules moderately dense ;
they should be well-formed and separate, and should form the only
shaped portion of the milk. Milk of older cows is generally richer
in large globules.

If the majority of the globules is small and poorly shaped, it
indicates that the milk is poor in fat, and lacks in nutritive
qualities.

Watered and skimmed milk: The watered milk contains
the fat globules in the same proportion, as far as size is concerned,
as they are found in normal milk. The number of globules in the
field differs according to the quantity of water added.

Skimmed milk generally contains none of the larger butter
globules, these having been removed with the cream.

Value of microscopical examination: The value of milk
can never be determined by means of the microscope. Author
concurs here with Vieth, who says: “The microscopical exam-
ination of milk may, under circumstances, furnish valuable indica-
tions, if used for the detection of abnormal qualities in appearance
or behavior, or the determination of foreign substances added to
the milk. Asa control for the determination of the fat, it has no
more value than other, even the best optical methods.”

Colostrum corpuscles: QOolostrum corpuscles are globules of
from four to five times the diameter of the fat globules. They
consist of proto-plasma which encloses fat globules. Occasionally
an eccentric nucleus may be observed (see cut, page 16).

Pus; Pus corpuscles in milk appear as pale globular bodies of
varying size. They possess a slightly granulated surface, which
disappears on addition of acetic acid, while the corpuscles get con-
siderably enlarged.

Pus corpuscles and epithelial cells.

Epithelial cells are found in milk but rarely, and then, per-
haps, accidentally.

Lower organisms: The presence of fung? in milk can be de-
tected with the naked eye only when they are grouped together in
one place in dense masses. They have received considerable atten-
tion of late. It is, therefore, indicated to determine whether, in
the dairy industry, they are of equal importance as we know them
to be in other industries. The development of fungi is generally
a very complicated process, embracing a cyclus of the most hetero-
geneous shapes. Moreover, these various forms depend for their

*

17

development on the nature of the s@bstance upon which they
grow. The air contains, normally, fungi; but it contains far more
in damp and badly-ventilated stables. It is, therefore, but natural
that milk should contain them also, since the air cannot be ex-
cluded. When milk, on standing, sours or decomposes, we find,
therefore, always fungi, whether the process is a normal or an ab-
normal one. It is not absolutely, but at least reasonably certain,
that these’ changes are produced by fermentation, from the fact
that Appert’s milk-preserving process is successfully applied in
dairies,

The following species of fungi have been found in milk which
is undergoing decomposition :

1. Oidium lactis, now known as mycoderma lactis, milk yeast.
2. Mucor racemosus Fres.

3. Penicillium glaueum Link.

4. Dictyostelium mucoroides Bref.

With these we always find bacteria and various species of
vibrio, zooglcea and monades.

Specfic Gravity.

Definition: Specific gravity is the figure which indicates the
relation of the weight of a body, as compared with the weight of
an equal volume of distilled water at the same temperature. The
specitic gravity of milk, determined at 15° C., depends upon its
composition, and varies between certain limits. Albuminates,
milk sugar, and salts increase its specific gravity, fat diminishes it.

The difference in the specific gravity of milk, just after milk-
ing, or after standing for some time, or boiling, is, perhaps, due to
the air which dissolves in the milk during the milking, when it is
thus in thin layers exposed and thoroughly mixed into it.

The butter globules may be liquid or solid, according to their
temperature and composition, and the specific gravity of milk may
by this be influenced ; but how and to what extent this is done,
has not yet been investigated.

Apparatus for the determination of the specific gravity:
The specific gravity of milk is determined—

1. For scientific purposes, by weighing the milk in a flask of
known contents (pycnometer).

18

2. For practical purposes, by the use of an areometer (lacto-
densimeter).

Weighing in a flask: The flask used for the determination
of the specitic gravity is of thin glass, and is closed with a care-
fully ground, solid glass stopper, or one consisting of a thermometer.
The latter are, for convenience sake, to be preferred. This flask
should hold from 30 e.c. to 50 ¢.¢., and the edge of its neck should
not be laid outward and rounded, but cut off straight. To clean
these flasks after use, they should be rinsed with caustic soda solu-
tion, then with water and absolute alcohol, and finally with ether.
Cloth should be used, instead of paper, to dry and clean them ex-
ternally.

It must be avoided to touch the flask with the hands while it is
used, to prevent changes to temperature, which, by the consequent
expansion of the fluid, would lead to inaccurate results. The tem-
perature of fluids, the specific gravity of which is thus to be de-
termined, should not vary more than 2° from the temperature of
the air in the balance-room. Should it be warmer, it would hap-
pen, especially in the case of milk, that the fluid at the sides be-
comes colder and commences to contract, while in the interior,
around the mercury bulb of the thermometer, the fluid retains its
original temperature. It is necessary, therefore, to determine the
temperature of the room by another thermometer. The tempera-
ture exerts a considerable influence upon the results. Therefore,
to obtain exact readings, the bulb of the thermometer should remain
in the fluid for at least one or two minutes, and then be read to
0.1 degree. The specific gravity found is corrected by the use
of Kopp’s tables.

VotumiInA AND SpeEciric Gravity oF WATER, ACCORDING TO

H. Kopvr.
TEMPERATURE, Volume of the Water Spec. Gr. of the Water
Centigrade, Fahrenheit. ato’ C, =1. ato°C, =1.
0. 32.0 1.00000 1.000000
1. 83.8 0.99995 1.000053
2. 35.6 0.99991 1.000092
3. 37.4 0.99989 1.000115
4, 39.2 0.99988 1.000123
5. 41.0 0.99988 1.000117
6. 42.8 0.99990 1.000097

19

TABLE CONTINUED.

TEMPERATURE. ' Volume of the Water Spec. Gr. of the Water
Centiyrade, Fahrenheit. ato°C, =1, at o° C, == 1.
7. 44.6 0.99994 1.000062
8: 46.4 0.99999 1.000014
9: 48.2 1.00005 0.999952
10. 50.0 1.00012 0.999876
11. 51.8 1.00021 0.999785
12. 53.6 1.00031 0.999686
18. 55.4 1.00045 0.999572
14. 57.2 1.00056 0.999445
15. 59.0 1.00070 0.999806
16. 60.8 1.00085 0.999155
17. 62.6 1.00101 0.998989
18. 64.4 1.00118. 0.998817
19. 66.2 1.00137 0.998631
20. 68.0 1.00157 0.998435
21. 69.8 1.00178 0.998228
22. 71.6 1.00200 0.998010
23. 73.4 1.00228 0.997780
24. 75.2 1.00247 0.997541
25. 77.0 1.00271 9.997293
26. 78.8 1.00295 0.997035
27. 80.6 1.00819 0.996767
28. 82.4 1.00347 0.996489
29. 84.2 1.00376 0.996202
30. 86.0 1.00406 0.995908

Determination: The flask, after having been thoroughly
cleaned, is dried’at 100° C., and left to cool in the desiccator. It
is then weighed, and after that filled with water which has previ-
ously been freed from air by boiling, and been left to cool ina
covered flask. Care must be taken that no air bubbles adhere to
the glass. The stopper is then adjusted, and the outside carefully
dried. It is then re-weighed, and the temperature observed. The
contents of the flask, at a certain temperature, are thus deter-
mined.

After removing the water and drying, the bottle is filled with
the milk, which has first been well mixed, using throughout the
same precautions. If the temperature of water and milk are not

20

the same, the observed weights must be corrected by the above
table in the following manner :

Found, weight of empty bottle................ 15.235
“ — bottle + water at 18° C...... 46.327

Weight of water at 18° O.............06% 31.092
Weight of bottle + milk at 16° O......... 47.226

© 6% 6 empty... cece cece ees 15.235

Weight of milk at 16° Cy. c0-cssecveveers 31.991

The water having been weighed at 18° C., we have to deter-
mine the quantity of water required to fill the flask at 16°C. The
respective specific gravities of water are:

At 18° C., 0.998817; at 16° C., 0.999155.

The weight of the water required to fill the flask at 16° C. is,
therefore,
0.998817: 31.092 = 0.999155: X
X = 81.102 grs.
31.991
= 1.028.

The specific gravity of the milk is, therefore,
31.102

This is the specific gravity of the milk at 16° C., compared with
water at 16° C.

Since the coefficients of expansion of milk and water differ cer-
tainly not considerably, we can also consider the specitic gravity of
this milk to be = 1.028 at 15° C., if compared with water of this
temperature.

If once the contents of the flask are known, it is unnecessary
to repeat the weighing with water for each determination. It is
only necessary, from time to time, to examine the weight of the
flask, to ascertain whether it has not lost in weight by the removal
of small splinters of glass or by scratches.

Lactodensimeter: For ordinary determinations an areometer
or lactodensimeter may be employed to ascertain the specific
gravity. Quevenne’s lactodensimeter is the most exact, and the
one most generally used. For description and use of this instru-
ment, we refer to the chapter treating on “ Milk inspection.”

21

Chemical Analysis of Milk.
GENERAL RULES.

For the examination of milk one must be enabled to commence
the examination at once, and to carry it through without loss of
time. It is, therefore, absolutely necessary that the laboratory be
well supplied with all the apparatus mentioned at the end of this:
book, in such quantity that no time is lost by preparations of any
kind.

The first process taken in hand consists in the coagulation of
the milk. When this is in progress the determination of the
solids and salts is commenced. After the filtration from the co-
agulated albuminates is finished, and while the milk is drying on
the water bath, the physical properties and the reaction of the milk
are determined.

Milk should be thoroughly mixed before samples for the various
determinations are removed. For exact analyses it is also necessary
not only to measure the milk, but to verify and correct the figures
obtained by measurement by actual weighing in a covered vessel.

A careful and exact record of all data concerning the analysis
is indispensable. Measures should be given in cubic centimeters
and weights in grammes ; and for the measurement of the temper-
ature, the Celsius or Centigrade thermometer should be employed.

In case that the temperature has been observed on.a Fahren-
heit thermometer, the corresponding degrees of the Celsius ther-
mometer may be found by the table given on page 18. For higher
temperatures than those given in this table, the corresponding
temperature on the Centigrade thermometer may be found by
deducting 32 from the degrees read, dividing the rest by 9, and
multiplying by 5. For instance:

(185—82) x 5
185° F= ——— = 85°C.

9
and, vice versa, we may convert Celsius degrees into degrees
Fahrenheit by the following equation :

85 x 9
85° C. = —— + 32 = 185° F.
5

22

Reaction of Milk.

While former investigators assign to milk always either an acid,
alkaline or neutral reaction, later investigations have proved its re-
action to be amphotere. Soxhlet states that a milk of only acid or
alkaline reaction is an impossibility, since basic, neutral or acid
phosphates never show a neutral reaction. To add to milk alkali
until no acid reaction can be observed, would produce a milk of
strongly alkaline reaction. The opposite takes place when, with
the aid of acids, we desire to extinguish the alkaline reaction.

This amphotere reaction can, however, only be proved by the
use of specially prepared litmus paper (see Fresenius, Qual. Analy-
sis), or better yet, with Liebreich’s litmus plaster plates (Bert. Ber.,
1, 48).

To test for the reaction, one drop of milk is brought by means
of a glass rod upon the test paper (blue or red). If the red is
turned blue, we have an alkaline reaction, or if the blue be turned
red, an acid reaction. No change on either would prove a neutral
reaction.

The reaction most generally observed and reported is the neutral
reaction.

Determination of Water and Solids.

The solids are determined as follows :

10 ec. milk are carefully weighed in a dry, counterpoised
and covered platinum dish. To this absolute alcohol sufficient for
coagulation is added. The coagulated mass is then dried on a
.water bath ; and, before it has lost all its moisture, it is, by means
of a spatule, carefully spread over the sides of the dish to increase
its surface, whereby drying is greatly facilitated. It is then
brought into an air bath, and dried to constant weight at from 100
to 110° C. To this end the weighings are repeated every hour,
the dish, with cover, being allowed to cool in a desiccator before
each weighing. We thus have:

Platinum dish + cover + dry solids,
Minus platinum dish ' cover,

Leaves dry solids.

23

Difference between milk taken and dry solids = water + vola-
tile substances.

Good milk should have 12.5 per cent. of solids.

Determination of ashes and phosphoric acid: The residue
from the determination of solids is then heated first over a small
flame, and finally at a dull-red heat, until complete incineration is
effected. It is advisable to incinerate, if possible, in a muffle.
The dish is then covered, and allowed to cool in the desiccator, and
finally weighed.

Platinum dish + cover 4- ashes,
Less platinum dish + cover,

Leaves ashes.

The ashes of milk vary from 0.5 to 0.75 per cent. More than
0.75 per cent. found in an analysis would indicate the addition of
alkalies, which are frequently used during the hot season in the larger
cities to retard souring. The reaction of such ashes is then alkaline,
and will show effervescence on the addition of acid. The ashes of
normal milk show a neutral reaction, and do not effervesce with
acids.

The phosphoric acid is easily and accurately determined by
the following method: In the manner stated above, 50 c.c. milk are
dried and incinerated. The salts are then dissolved with some
hydrochloric acid, and the solution is brought to 20¢c. To 10
c.c. of the cold solution, ammonia or caustic soda is added until
the reaction of the fluid has become alkaline. This is then acidi-
fied with acetic acid. The solution thus treated contains but
little acetates, which would interfere with the deltcacy of the end
reaction of ferrocyanide of potassium and uranium. To this. solu-
tion a standardized solution of uranium is added. When the pre-
cipitate ceases to increase, the whole is boiled for a few minutes,
and one drop of the clear supernatant liquid is brought on a porce-
lain plate, and tested with a solution of ferrocyanide of potas-
sium. A brown coloration indicates the presence of an excess of
uranium solution, which, however, may disappear again on con-
tinued boiling. The addition of uranium solution is continued
until the reaction remains. It is of advantage to make two titra-
tions at a time, using in one 0.5 ¢.c., between the tests, and in the
other, 0.1 c.c.

24

The uranium solution is made of such strength that 1 cc. =
0.005 gr. phosphoric anhydride. As regards the composition of
milk ashes, we refer to page 8.

For a complete analysis of the ashes, not less than 500 ¢.c. of
milk should be taken. For the method of analysis to be pursued,
we refer to Fresenius, Quantitative Analysis.

Coagulation and Determination of Albu-

minates and Fats.

In the method until now commonly used, the coagulation was
effected by acetic acid or carbonic anhydride. This method orig-
inates with Hoppe-Seyler, but gives inaccurate results, as has been
proved by the investigations of Liebermann, Manetti, Musso,
vy. Nencki, and the author (see Kritik der Verschiedenen Methoden
zur Bestimmung der Albuminate und Fette, Presenius’ Zeitschrift,
1880, and Petersen’s Lorschungen, 1879, 7, 301.

A very reliable and quick method is Ritthausen’s, who proposes
to effect the precipitation of the albuminates and fats by means of
sulphate of copper solution. From a neutral or slightly acid solu-
tion, the coagulation is easily effected in the cold. The accuracy
of the method has been verified by a long series of examinations
of milk in which it has been employed.

Ritthausen proposes to dissolve 63.5 grs. pure sulphate of cop-
per in crystals to 1 liter. 10 c.c, of this solution contain 0.2 gr.
CuO. A second solution contains 50 grs. caustic potash in 1 liter
of water. Its specific gravity is 1.048. Author uses the same
solutions, but has modified Ritthausen’s method by using a smaller
quantity of sulphate of copper.

The coagulation is carried out as follows: 10 ¢.c. milk are
weighed in a beaker covered with a watch-glass, and then diluted
with 100 ¢.c. water. After mixing well, the solution of sulphate
of copper is gradually added until the precipitate settles well,
while the liquid becomes perfectly clear. For this 2.5 to 3 ec. of
copper solution are required, while Ritthausen uses 5 c.c.

Then potash solution is added to decompose the excessive
quantity of cupric sulphate. For this, one-half the volume of the
copper solution is required. The coagulated albumen enclosing

25

the fat globules settles quickly, leaving the fluid perfectly clear.
The fluid is decanted through a filter which had previously been
dried at 110°C., and weighed between two watch-glasses. The
precipitate is then stirred up with 100 cc. of water. After al-
lowing to settle, the water is likewise decanted through the filter,
and finally the precipitate is brought upon it. The beaker is then
cleaned by means of a rubber washer, and washed with water until
everything is transferred to the filter. Thus, about 240 cc. of
filtrate are obtained, which are diluted to make it exactly 250 c.c.
This filtrate is used for the determination of milk sugar.

The beaker contains always some fat, which must be added to
the fat obtained from the albumen precipitate, and is, therefore,
set aside until this operation is in order. The copper casein pre-
cipitate, containing all the albuminates and the fat of the milk, ex-
cepting that portion which was left on the beaker, is then, by
means of a small spatule, well distributed over the whole surface
of the filter, which had been previously transferred to a large watch-
glass. This aids the evaporation of the water considerably, and
becomes necessary from the fact that the application of higher
temperatures must be avoided. To effect drying, the filter may
be exposed to the sun, or the watch-glass may be placed where it is
exposed to a moderate temperature. From time to time the pre-
cipitate is again worked with the spatule, care being taken that
the filter is not injured. After some time the residue becomes a
finely divided dry powder, which can easily be collected in the
point of the filter, and from which the fat can be extracted.

Determination of fat: The ordinary open extraction of the
fat, consisting in the washing of the precipitate with warm ether
on an open funnel, until the precipitate is exhausted, has disadvan-
tages, resulting not only in a loss of fat by effervescence, but also
in the waste of a considerable quantity of ether. Far more eco-
nomical is the use of a closed apparatus for the extraction of fat.

26

The apparatus constructed for this purpose by the author is ar-
ranged as follows:

&
x]
&

J

A is a flask of from 5 to 6 centimeters in width and 6 to 7 cen-
timeters in height. On this stands the funnel B, the neck of the
funnel being carefully adjusted into the neck of the flask by
grinding. The funnel is from 6 to 8 centimeters wide and from
8 to 10 centimeters high. The upper edges, d d, of the funnel
are bent outward to allow of an easy adjustment of the cork, and
the lower aperture must remain of full width, and should not
be narrowed down, as is often done.* The filter containing the
precipitate is then loosely inserted into the funnel, which then is
adjusted to the previously weighed flask. The filter is now washed
with some absolute alcohol to remove the last traces of moisture
from the precipitate. The beaker, which had been used for the
coagulation, and which had been set aside, is now freed from fat
by repeatedly washing it with small quantities of ether, which are
poured upon the filter. This is continued until the flask is filled
to about one-half with ether.

The apparatus is then, by means of a good cork, free from
pores,+ connected with an inverted Liebig’s cooler, and put upon a

* An ordinary wide-necked flask, to which the funnel is attached by means
of a good cork, may serve in the place of the complete apparatus, as described.

+ Corks may be prepared by covering the outer surface with silicate of
. soda,

27

sand bath, which is cautiously heated by means of a Bunsen
burner. The heat must be so regulated that the filter swims con-
tinually to one-half its height in condensed ether, and the cooling
must be sufficient to prevent the escape of ether. Thus the com-
plete extraction of the fat may be effected in about one hour. The
funnel is then removed, and the flask is connected with a cooler,
and the ether, which contains alcohol, recovered by distillation at
very low temperature. The flask is then put in an air bath, laying
it on its side, and dried for one or two hours at a temperature of
100 to 105° C. After cooling in a desiccator, it is weighed.

The increase of weight corresponds to the amount of fat con-
tained in the quantity of milk taken for analysis. The residue in
the filter is then dried:for two hours at from 110 to 120° C., and
weighed between two watch-glasses. After this it is transferred
to a porcelain or platinum crucible, and incinerated.

Weight of filter + dry coagulum,
Minus weight of filter + ashes,

Leaves albuminous substance.

The nitrogen determination in this substance, if required, must
be made by Dumas’ method, on account of the presence of cupric
oxide, which, in an attempt to use Will Varrentrape’s method,
would cause a loss by the partial destruction of the ammonia. The
determination of albuminates by simple incineration, is, however,
sufficiently exact.

For a description of Dumas’ method for the determination of
nitrogen, we refer to Fresenius, Quantitative Analysis.

A separation of so-called albumen and casein is wrong; a de.
termination of the sum of all albuminons substances is, generally,
all that is required, if the investigation is not to go into such de-
tails as those mentioned on pages 6 and 7.

Determination of Milk Sugar.

The sugar of milk is determined in the 250 c.c. fluid which
have been filtered from the coagulum obtained by the addition of
cupric sulphate to milk. The method adopted by the author con-
sists in the titration by means of Fehling’s solution.

M4 a

28

It is well here to mention that sugar of milk is the only sugar
which can accurately be determined by the use of this method,
provided the original plan of manipulation is adhered to.

The author proposes to prepare two separate solutions to avoid
the changes which Fehling’s solution always undergoes. To this
end he prepares a standard copper solution, containing in 1 liter at
15° C. 34.64 cupric sulphate, purified by repeated crystallizations,
grinding, and drying between filter papers. The second solution
is prepared by dissolving 173 grs. of rochelle salts in 850 cc. of
water, and boiling. After cooling, 600 ¢.c. of sodium hydrate solu-
tion (sodium hydrate purified by crystallization from alcohol) of 1.12
specific gravity, which had likewise been heated to boiling, are
added. The mixture is finally brought to 1 liter at 15° C.

These two solutions are kept separate in a number of small
well-corked bottles, and are only mixed when used.

For the titration of the sugar, the following plan has been
adopted : 5 ¢.c. of each of these solutions are brought into a por-
celain dish, with 20 ¢.c. of water, and heated to boiling. The sugar
solution is then gradually added from a burette, care being taken
that the solution is kept boiling constantly.

Evaporated water should, from time to time, be replaced by
the addition of distilled water. The formation of dry crusts on
any part of the dish must be prevented. They are likely to get
overheated, and thus may give rise to the formation of products
which also reduce copper solution. The titration should be re-
peated at least once, and must be completed within five to ten
minutes. The process is at an end when all the copper is thrown
down as red cuprous oxide, which is best determined by the com-
plete disappearance of the blue color in the liquid. To observe
this better, the dish is slightly inclined, so as to enable one to ex-
amine the color against a white background. In doubtful cases, a
trace of the fluid is filtered through a very simall filter, acidified
and tested with potassium ferrocyanide. A red color indicates the
presence of copper, and a few more drops of the sugar solution
are added, the boiling being continued until the precipitation of
the copper has been completed. Care should also be exercised that
no sugar remains in the fluid. If, therefore, no copper reaction
ensues, we must always test for sugar in a separate portion by the
addition of copper solution, and boiling.

29

It is to be observed yet, that the decolorized solution, on stand-
ing over the cuprous oxide, absorbs oxygen from the air, and be-
comes again blue. For this reason each tritratiun must be carried
to an end in the shortest time, and a subsequent coloration is not
to be taken into account. We, therefore, determine the exact
quantity by two to three titrations. The first titration is only used
to determine the reducing qualities roughly.

1c.c. Fehling’s solution = 0.00676 grs. milk sugar.

It is not advisable, as some propose, to take a drop of the fluid
out by means of a glass rod, and to test this on a porcelain plate
for copper, as described above. Finely divided cuprous oxide re-
mains frequently for a long time suspended in the fluid, and the
least trace of it in the fluid is apt to deceive.

The calculation is as foliows :

Provided we used 18.2 c.c. of the sugar solution to reduce 5 ¢.c.
copper solution, we have:

18.2 : 250 = 0.0338 : X
X= 0.464 milk sugar.

Occasionally the sugar of milk is determined by difference.

According to the method of Sowhlet, 25 c.c. milk are diluted
with 400 c.c. water, and coagulated by means of a solution of sul-
phate of copper; the precipitate is filtered off, and the fluid is
brought to 500 c.c.

100 c.c. of this solution are then transferred to a beaker, and,
after adding 50 c.c. of Fehling’s solution, are boiled over double
wire netting, while the glass is kept covered to prevent loss. After
six minutes’ boiling, the sub-oxide of copper is collected on an
asbestos filter, dried, and reduced by heating in a current of hydro.
gen gas. The method is said to give quick (#) and accurate re-
sults. According to Soxhlet’s investigations,

mers. of copper weighed correspond to mgrs. milk sugar:

393.7 300
363.6 275
383.0 250
800.8 225
269.6 200
237.5 175
204.0 150
171.4 125

138.3 100

30

ABNORMAL COWS’ MILK.

Abnormal cows’ milk is not merely an adulterated milk, but
all milk which is not fit to be used as food without detriment to
the interest of the consumer.

Colostrum Milk.

The colostrum is the first nourishment for the young animal,
and, as such, of considerable importance ; but it is not suited for
dairy use. All dairy societies, for this reason, prohibit its sale.
Condensed milk factories refuse the milk until the sixth day after
calving, while in cheeseries they accept it only on the eighth day,
since colostrum is said tu interfere with the curdling and the sub-
sequent process of ripening of the cheese.

Eugling has made very thorough investigations regarding this
milk. He says: “ The first three to four liters of the beastings milked
“after calving, are a yellowish-white mucilaginous fluid, which is
“ frequently colored by blood, exhibiting a reddish-brown tint. It
“ possesses a peculiar odor, and has, at 15° C., a specific gravity of
“from 1.06 to 1.08.

“ The cream rises very slowly ; but, after long standing, where-
“by a skin of dry albuminates forms on the surface, from 50 to 75
“ner cent., by volume, of cream is obtained. The boundary be-
“tween milk and cream is not well marked.

“ Colostrum is, on heating, converted into a solid cake. It pos-
“sesses originally an acid reaction, and keeps well, especially after
“a dry albumen skin has formed on its surface. It then appears un-
“changed, even after two weeks’ standing. The casein, on curd-
“ling, developes a gas, and between the heavy flocks remains a red-
“dish-colored, opalescent serum, which bears great similarity to
“blood serum. The products obtained after this first milking as-
“sume gradually the character of cows’ milk, until, after four days,
“the secretion of the glands shows all the properties of normal
“ milk.”

The change from colostrum to milk which may be used for in-
dustrial purposes, is, therefore, effected in a comparatively short

31

time. It is slower with younger animals and such which are of
inferior development, as far as production of milk is concerned.

Good milking cows will generally on the third or fourth day
after calving, produce milk which can be boiled without showing
any coagulation of albuminous matter; while young animals will
furnish, even on the sixth and seventh day, a milk which will
show partial coagulation on boiling, and in which colostrum cor-
puscles can be found with the aid of the microscope.

Beside blood, albumen, casein, fat, and ashes, we find the fol-
lowing substances as normal constituents of colostrum: sugar,
globuline, nucleine, urea, Jecithine, and cholesterine. The pres-
ence of milk sugar has, as yet, not with certainty been demon-
strated. Eugling found the colostrum of twenty-two cows, of the
ages from three to thirteen years, composed as follows:

Specht. PTAVIEY .e.0 sein weee nen 1.058 1.079
Aish@sexne asa witnesses 1.180 2.310
EOE sss coikk Been ava aceseeoses cin aaa 1.880 4.680
Albuminates.............0000 11.180 90.210
aSeIN sc agcai bees aoe ee me 2.650 7.140
DIU vacnarsocrasneuuoruwata 1.340 2.830

Colostrum milk is especially characterized by comparatively
large (0.005 to 0.025 m.m. diameter) granulated corpuscles. Aside
of these, fragments in various degrees of dissolution are found,
which frequently consist only of conglomerates of fat globules.
Bunches of cells from the lactiferous ducts, generally larger than
the colostrum corpuscles, are also occasionally met with (see fig.,
page 16).

Poisoned Milk.

Metallic poisons: Milk may occasionally contain poisonous
metallic substances. These are derived either from sour food
kept in metallic vessels and consumed by the cow, or may be im-
parted to souring milk which is kept in metallic vessels. (Taylor,
On Poisons, p. 412.) The acids which are formed during souring
dissolve the oxides of copper, lead and zinc easily. It is said that
zine vessels are used in some localities to delay the souring.

Examinations For Meraruic Porsons: If the presence of
large quantities of metallic substances is suspected, the examina-
tion may be carried on in the following manner:

32

From 50 to 100 ¢.c. of milk are precipitated with a few drops
of muriatic acid. After heating to boiling, the solution is filtered
from the precipitate, and the latter washed. The solution is then
evaporated to about 25 @c., and again filtered to remove some
albumen and fat, which have become insoluble during the concen-
tration of the liquid. The concentration of the fluid is then con-
tinued until about 10 cc. remain. These are distributed into
three test tubes, one being used for the determination of the
presence of zine, another for copper, and the last for lead.

The presence of zinc is determined by means of sulphuretted
hydrogen passed through the. almost neutralized solution, <A
white precipitate would indicate the presence of zinc. Frequently
sulphur is precipitated, which, however, on heating on platinum
foil, burns without leaving a residue. The precipitate is there-
fore to be more closely examined. The hydrochloric solution
is made alkaline with ammonia, and sulphide of ammonia added,
when a white fiocculent precipitate will be formed in the presence
of zine. In case that only small quantities of zine are present,
white turbidity ensues, and the precipitate becomes flocculent only
after long standing.

Lead is found in the hydrochloric solution by passing sulphu-
retted hydrogen through it, which produces a grayish-black pre-
cipitate. Chromate of potassium produces a yellow precipitate of
chromate of lead.

In the presence of copper, ammonia produces a dirty gray
color; potassium ferrocyanide a brownish-red color, or precipitate.
If some of the solution be brought on a clean piece of platinum
foil, and a clean knife be laid upon it, the latter becomes, in the
course of several hours, coated with a layer of red metallic copper

If these metals are present in only minute quantities, it is bet-
ter to destroy the albuminous matter by means of hydrochloric
acid and chlorate of potassium. The rest of the operation remains
the same.

Vegetable poisons: A case is on record wherein, in the City
of Rome, twenty-one persons were poisoned, in the year 1875, by
the milk of goats which had fed upon momordica, the fruits of
which are known to possess highly purgative properties. The pa-
tients recovered under medical treatment.

33

Milk Containing Medicines.

Lewald’s experiments have proved that medicinal substances
are rapidly conveyed by the milk; so, for instance, lead, arsenic,
oxide of zinc, sub-nitrate of bismuth, tincture of iodine and iron,
antimony, and mercury salts.

It has not been determined that milk suffers, under the influ-
ence of these substances, also a quantitative change; but the expe-
rience of physicians has demonstrated that medicines administered
to the mother act, through the medium of milk, upon the suck-
ling.

Milk as the Cause of Disease.

It is a well-known fact that the use of milk, especially during
the hot season, when it undergoes changes quite rapidly, is attended
with some risk. Only later investigations have proved that milk
may also cause specific diseases. Milk has, in many cases, proved
to be the bearer of disease germs, and thus has caused the trans-
mission of contagious and infectious diseases.

Without reference to special cases, we will, to avoid prolixity,
only describe the diseases and their causes.

The milk may be the cause of infection :

8 %
ses ©. wy
ig ote “a %
ee wes o DN
% otee a @

Bon:

FEES

Milk containing alge, obtained from Bacteria.
a cow which drank stagnant
water. According to Low.

1. By direct communication of the infection, derived mainly
from impure water, used either for watering cattle or as adulter-

34

ant of milk, or for cleansing the vessels used for keeping the
milk. John Oyle observed that cattle using stagnant water during
summer, became feverish. The microscopic examination of blood
and milk proved, in both, the presence of large numbers of micro-
scopical organisms, the same as were found in the water. The
milk was unfit for use, and normal milk mixed with a few drops
of the same water would undergo the same changes.

So may bacteria or spirilla, by reason of the use of impure water,
or other means, enter the milk, where they produce putrid fer-
mentation, which only in its latter stages is easily recognized by
odor and taste. These smallest organisms, variously magnified, are
represented in the cut given on page 33.

2. By absorption of the infectious material from the air of
the stable and dairy, or by contact with sick persons.

3. By abnormalities pre-existing in the milk, from the fact
that it is derived from sick animals.

Considering that a contagion finds in milk not only the condi-
tions for its preservation, but also for its propagation, we must
admit the possibility that, by the use of infected water for rinsing
milk vessels, the small quantity of water adhering to the sides of
the vessel may well suffice as a cause of disease. The same is true
for infection by air.

In England, many epidemics oceurred which have been traced
to the milk as cause; and, amongst these, impure water, employed
in the manner described, seems, in most cases, to have been the
originator.

Robinson mentions one case where milk, which was stored in
the sick-room of a typhus patient, caused an epidemic of typhus.

Bell relates an epidemic of scartatina, which was caused
amongst the customers of a certain dealer whose cows had been
milked by scarlet fever convalescents.

A similar case is mentioned by Taylor.

Gerlach was the first who called attention to the dangers to
which consumers of milk are exposed, which is derived from cows
sick with tuberculosis. This chronic disease attacks mainly stable-
fed animals, which transmit this disease to hogs, sheep, calves and
rabbits fed upon their milk.

Stang mentions the case of a child which died with all symp-
toms of tuberculosis, and which had been infected by the use of

35

the milk of a tuberculous cow. Experiments of Klebs have
proved that the contagion is not destroyed by the ordinary boiling
of the milk. Ballinger has lately corroborated these observations.

The milk of tuberculous animals is said to be thicker than
ordinary milk. The reaction is alkaline. The cream rises quickly.
Cream and milk are apt to putrefy in a short time. The milk is
not easily curdled by rennet or by heating.

Anthrax: Milk of cows sick with anthraw is said to become
stringy, and in this state it breaks easily. Infected milk should
not be used. It is said that cattle are predisposed to this disease
when fed on distillery swill or the refuse of starch and beet-sugar
factories. :

Aphtha epizootica: Anaker says: “In some cases of aphtha
“ enizootica (hoof and mouth disease), especially when the mucous
“ membranes of the lacteal ducts are affected, or when the contents
“ of the bladder find their way into the milk during the milking,
“the milk appears thicker, phlegmy, more yellow, lumpy, and
“ blood-streaked. It emits a putrid odor, and possesses a repug-
“nant taste. Such milk will part, on standing, into a yellow se-
“yum, and a sediment which contains pus corpuscles and finely
“ granulated masses in a state of dissolution. Such admixtures
“ increase the specific gravity of such milk, while the percentage
“ of fat, casein, and sugar are diminished.

“The amount of salts is increased. The reaction of the milk
“is acid when the disease is at its height. It, therefore, curdles
“ easy when heated to boiling. The cream yields often no butter .
“ but butter made from such milk shows an unnatural yellow color.
‘Whether such milk will prove injurious to the health of con-
“‘ sumers, depends upon the nature of the abnormal constituents.

“ Boiling does not always remedy the injurious properties of
“such milk. The use of such milk has been the cause of the fol-
“lowing symptoms: fever, blisters on the mouth and feet and the

36

“hands, of the milkers, headache, and rheumatic pains affecting
“ the whole body.”

Milk of cows sick with the mouth and hoof disease. Acccording to G. T. Brown.
Aside of the easily recognized butter globules, it contains large, dark,
and granulated cells, vibrios connected to strings, and small
elliptic bodies, of which always two are connected
and show motion (Jacteria).

The infection through milk is considered to be partially caused
by small blisters on the teats, the exudation of which becomes ad-
mixed to the milk.

C. Monin examined the milk of a cow sick with cattle plague,
and found its composition very variable :

Water and volatile............. 81.22 to 86.53
aL ES iccda: lanaczigiecacuvenacnacestwle ave Binatone 118 “ 1.54
Albuminates............-..00. 9.07 * 11.19
sab Aaraeate amen cucu arapene tiers ces longs Ese i Es (y Gs a 99
UMIOE MM. seca ben ads 0.46 “© 1.85
Specie SUVS cas saw wens seam 1.002 “ 1.057

The milk in this affection is very rich in albuminates and salts
but poor in fat and milk sugar.

?

37

Influence of Food, etc.

The influence of food upon the milk of animals is a subject of
some importance, and should engage the attention of physicians,
since many waste products of important manufactures are at pres-
ent utilized for feeding purposes, either alone or in combination
with other food.

By means of such foods, substances may enter into the compo-
sition of milk, which make it totally unfit to serve as nourishment
for infants.

Much has been written and said to defend the use of such
waste products as food, yet nobody prefers such milk to milk from
cows which have been normally fed on good pasture.

Being constantly housed can, likewise, not be of advantage to
the well-being of an animal, especially if the stables are damp and
badly ventilated.

Potato distillery swill: Only a few fragmentary investiga-
tions have been made to determine the influence which is exerted
on the quality of the milk of cows which are fed on potato distil-
lery swill. That the milk of such cows cannot be good may be
presumed, if we consider that the swill is not always fresh, nor
free from alcohol.

Ried found that such milk did not contain alcohol, but that it
is very poor in fat (1 to 14 per cent.). The swill is poor in carbo-
hydrates, since the conversion of the starch into sugar, and finally
alcohol, is the object of the treatment.

Albuminates, acids and salts predominate; hence, such milk is
richer in casein and salts, and comparatively poor in sugar and fat.

Clark found that the fat globules of such milk are small and
few, and that they are disposed to adhere together, forming aggre-
gates of considerable size. In two specimens, uncommon numbers
of epithelial cells were observed, some of which showed a peculiar
granulation, while others were colored. Some of these were very
small and enclosed butter globules, thus showing that they had
formed the coating of the lacteal ducts, and that they had loosened
before their inner structure had been completed. The deleterious
influence on the health of consumers, especially that of children,
which is caused by such milk, has been traced to the circumstance

38

that such milk does not easily coagulate, and that the butter
globules are frequently united to large masses. Retarded coagula-
tion prevents easy digestion, and causes through an overloading of
the stomach, symptoms of irritation. (See Petersen, Ailchzeitung,
1877, No. 21, Ueber die schaedlichen Folgen der Branntwein-
schlempefuetterung fuer das Vieh.) -

Brewers’ grains: The investigations regarding the influence
upon the milk of cows fed with brewers’ grains are not conclusive ;
yet we know that such milk is inferior, unless the grains are fed
quite fresh.

Milk in fermentation: E. Reichardt mentions a case of rapid
Sermentation of milk in a village in the neighborhood of Jena,
Germany. He looked upon the high temperature of the store-room
as the main cause for this rapid fermentation. Everything that
may induce fermentation should be excluded from the dairies as
well as stables. Fermentation might also be caused by feeding
cows on fermenting brewers’ and distillers’ grains and wash. Pus
has occasionally been found in milk; it is derived from ulcers in the
interior of the udder. Other diseased conditions of the lacteal
glands may cause the presence of mucus in milk.

The facts related in the foregoing chapter are of great import-
ance, since they justify the so much needed sanitary inspection of
the milk as it reaches the markets, especially in larger cities; but
such supervision should be extended to include the animals them-
selves, their food, water and housing.

Observations as to sickness amongst cows, inferior drinking water
for the cows, and untidy handling of the milk, may frequently

@help to explain cases of sickness, especially amongst children.

Adulteration of Cows’ Milk.

The adulteration of milk—in our climate, cows’ milk—is in
larger cities an every day occurrence. The consequences of this
practice are the more to be deplored, as they mainly befall the in-
fants, who often depend upon milk as their sole nourishment. In
consequence of this, many children are committed to a sickly, and
languishing existence, while many perish. It is for this reason
that city governments experienced the necessity to prevent these
practices, by an inspection of the article as it reaches the market.

39

The adulterations are as follows:
1. Addition of water.

2. Partial removal of cream, skimming.
3. Skimming and watering.

4. Mixing of partially skimmed (evening or morning) milk
with whole milk.

5. Foreign substances to disguise the altered or unnatural ap-
pearance of milk.

Most cases of adulteration are to be classed under 1 to 4, those
under 5 being used to reestablish a normal appearance of adulter-
ated milk.

The following substances are known to be used for this purpose :
sugar, gum arabic, starch, dextrine, egg albumen, yolk of eggs,
earthy substances, alkalies and dyes, to blend the blue color of skim
milk.

Most of these adulterants exist more in books than that they
are actually met with, for substances which can easily be found
by simple chemical reactions, or even by mechanical means, or
which may easily be discovered by taste or smell, are not those
which fraudulent dealers would be apt to choose.

Those who adulterate know well that chemists possess all the
means to detect such coarse adulteration; they therefore confine
their operations mainly to watering, and the mixing of skim milk
with whole milk, in various proportions.

ry

Watery milk: Watery milk of a bluish-white color, poor in
fats and solids, is generally derived from cows under inferior treat-
ment, or when fed with extraordinarily poor and watery food. A
measure for the value of such milk is its specific gravity. This is,
however, governed by the quantities in which the various constit-
uents are present, for while salts, albuminates and milk sugar {nd
to increase the specific gravity, the fat tends to diminish it.

If whole milk be mixed with water, the specific gravity will be
reduced, and analysis will show an excess of water and, correspond-
ingly, a diminished quantity of solids.

If milk be more or less skimmed, the specific gravity is in-
creased. By means of the lactometer or lactodensimeter, dealers
are enabled to dilute it with water to such an extent, that the spe-
cific gravity reached is within the limits of the law. A determina-

40

tion of the fat will show whether this has been practised, as it will
also in the case of mixtures of skim milk and whole milk.

To determine whether an abnormally watery milk or a watered
milk is before us, we may use chemical or mechanical means. For
scientific investigations only the former are used, and must consist
in a complete quantitative analysis. For practical purposes, we can
confine ourselves to a determination of fat and total solids.

Physical examination: The physical examination of milk
consists mainly in the determination of the specific gravity. The
microscopical examination is not fit for quantitative results, but can
merely be used for the determination of abnormalities, as blood,
pus, and colostrum corpuscles, or solid adulterants. It cannot be
used to determine with certainty the adulteration with water,
though it is a fact, that watered milk contains the larger and smaller
fat globules in the same proportion as whole milk, though further
separated from one another. The want, or deficiency, of the larger
or medium size globules, would indicate skimming.

Conrad has shown how difficult it is to obtain a good sample on
a slide, representing really an average of the milk to be examined ;
the same milk well mixed furnishing, by all the care that can be
bestowed, samples which show differences as regards the number,
size and distribution of the fat globules.

The estimation of the number of fat globules in the field is also
quite arbitrary.

Later on, in the chapter entitled “ Milk inspection,” a method
for the determination of the fat will be described, which, if not
absolutely accurate, admits at least of safe deductions. The spe-
cific gravity of normal market milk (such which represents the milk
of several cows mixed), which possesses an average composition as
follows :

‘Water and volatile substances.................. 87.50
Pal bee eiscaedvon catevasarard innate Gc peareanand vas tapas eas ole cen at 0.50
SIS ait ceseer tat hs topes ants Settee crea ete cerca eo a 3.50
Albuminates.........0 0.00000. ccc cee cece ewes 4.00
Pa Ee hg ia gr re roca actrahe aces oon nanan ae 4.50

100.00

ranges, according to many thousand examinations, in different
countries, from 1.029 to 1.033, A milk, therefore, which contains

41

more than 87.5 per cent. of water, and which has a lower or higher
specific gravity than 1.029 to 1.033, must be considered as inferior
or adulterated ; also when it contains less than 3 per cent. of fat,
and when it otherwise shows considerable deviations from the
figures given above.

Yet such a milk cannot be directly considered as adulterated,
unless the sources of the milk have been examined, and until it
has been clearly demonstrated that the milk produced by the cow
does not show the same deviations from the average, as the milk
offered for sale.

Sour milk: The sale of sour milk, z. ¢., such which will curdle
on heating, should be prevented.

It happens frequently, especially during the summer, that milk
curdles before the examination could be commenced. Schroeder
and Dietzsch have stated that a simple determination of the specific
gravity of the whey is sufficient to establish an adulteration by
water. The specific gravity of pure whey is 1.026, and a lower
specific gravity would indicate addition of water. It would be
exceedingly desirable and would greatly aid in the inspection of
milk, if this statement could be verified by investigations in other
localities.

The following substances are used as adulterants:

Starch and flours: Such admixtures thicken the milk; the
taste and flavor of flour is easily distinguished. Such milks form,
on standing, a pasty sediment. After boiling or curdling, the milk
appears thready. The addition of starch is proved either by means
of the microscope, or by testing the whey after filtration and con-
centration to one-quarter its volume, with tincture of iodine, when
a blue color will ensue. .

Dextrine: Milk containing dextrine has a sweetish taste; the
concentrated whey with tincture of iodine, becomes light violet or
the color of red wine.

Gum arabic: The presence of gum arabic is determined in
milk by coagulation with acetic acid, filtering and concentrating
the serum to one-fifth its volume. Absolute alcohol precipitates
the gum as a white flocculent mass resembling casein (may con-
tain albuminates). Chevalier and Lassaigne state that this precip-
itate presents a streaky appearance.

42

Coloring matters: The use of colors for the coloring of butter
and cheese has become so common in dairies, that now we find
them occasionally used for the coloring of poor blue milk. They
may be detected in the following manner:

500 c.c. of milk are coagulated with acid, or better, by the addi-
tion of 70 per cent. alcohol.

The liquid is then filtered off and evaporated to 50¢c. Addi-
tion of soda or ammonia produces a dark brown color in the pres-
ence of turmeric.

‘1 Annato: A blue coloration on addition of concentrated sul-
phuric acid, would indicate the presence of annato.

Preservatives: To prevent the souring of milk during the hot
season, various substances have been recommended. The appli-
cation of these by producers and dealers should not be tolerated,
but should be left to the consumer’s choice.

Producer and dealer should attend solely to cleanliness of treat-
ment and the cooling of the milk, which even during the summer
is sufficient to allow the safe transportation of the milk for con-
siderable distances. To prevent souring, the use of carbonate or
bi-carbonate of soda or potash is tolerated in France and England.

To demonstrate their presence, 50 ¢.c. milk are coagulated with
70 per cent. alcohol. The fluid is filtered and evaporated to
dryness. The residue, on addition of hydrochlorie acid, will
effervesce when these salts had been used.

Neither normal whey nor milk ashes contain alkaline carbonates.

For a qualitative and quantitative determination of the alkalies
in milk, at least 500 ¢.c. are required. In some cases, milk of lime
has been used as a means of preserving milk. The reaction of
such milk is alkaline. After coagulation with acetic acid, the
whey is evaporated to one-sixth of its volume, filtered, and tested
with sulphuric acid, which, in the case of lime having been used,
will produce a precipitate of gypsum. (Chalk has also been em-
ployed. Of about 300 samples examined by Aditor for the Metro-
politan Board of Health, in New York, only one sample contained
chalk.)

Salicylic acid and salicylate of soda have, of late, been
recommended and used for the preservation of milk. To deter-
mine its presence, 100 ¢.c. of milk are coagulated by the addition
of 70 per cent. alcohol. The whey is filtered off, and evaporated to

43

one-eighth its volume. It is again filtered, and then shaken with
ether. Perchloride of iron added to the ether solution, will produce
a violet color if salycilic acid is present. Schulz states that a solu-
tion of salicylic acid in water, with some cupric sulphate solution,
becomes a beautiful emerald green. This reaction is even more
brilliant when the sodium salt is used, and can be easily recognized
when dissolved in the proportion of 1: 2000 parts of water. Al-
cohol hastens the appearance of the color. Acids and ammonia
prevent the reaction.

Boric acid and borax being more easily soluble, more active
and cheaper than salicylic acid, are used quite frequently as preser-
vatives. To determine their presence, 50c.c. of milk are coagulated
with some acetic acid, and the filtrate evaporated in a platinum
dish. The residue, after drying, is incinerated. The ashes are
then heated with some alcohol containing from 1 to 2 per cent. of
cone. sulphuric acid. When the alcohol is then lighted, it will
burn with a flame which appears green colored at the edges, if
boracie acid be present. H. Gilm proposes to use the following
method, which is said to have the advantage of not only pro-
ducing a greener flame, but one which appears uniformly colored.
The boric ether vapors produced by the boiling of boric acid,
concentrated sulphuric acid and alcohol, are passed through a
narrow tube into a wider tube standing in vertical position. The
mixture of air and vapors is then ignited at the upper end of the
wider tube.

Quack preservatives, at very high prices, are also in use, and
widely advertised. The most widely known are:

Aseptine, which is recommended for the preservation of milk and
cream, and which, according to Nettl and Fleck, consists merely of
finely pulverized boracic acid.

Glacialine is a mixture said to contain mainly boracie acid
and borax.

44

MILK OF OTHER ANIMALS.

Goats’ Milk.

Goats’ milk is for the mountaineers what cows’ milk is for the
inhabitants of the flat lands, for the reason that at places where
cows fail to obtain sufficient nourishment on pasture, or where this
could be obtained only under great danger, the goats will yet
thrive. The goat serves as the poor man’scow. The properties of
goats’ milk are as follows:

Appearance: Color, white to yellowish.

Consistency : Generally thicker than cows’ milk.

Odor : Specific and strong, especially developed in the milk of
goats which are kept in the stable.

Taste: Specific and sweetish.

Specific gravity: Varies considerably and averages from 1.028
to 1.036.

Chemical composition : It is richer than cows’ milk, but vari-
able in composition.

Specific gravity average, 1.032.

Water and volatile substances........... 85.0 — 87.00
PALER etetiey <asee Clty ba ape ansineeta pananegeuat ae Macca nees 0.5 - 0.75
AlbUmMIMatesss wc ng sircGacavanatcne swat awe 4.0 — 6.00
TOG ah hace hiin hua dictove Seienechceeeh eet aaa eos eres 3.5 — 5.00
Mlk SUPA :.woa ves ve vee saws tee 0d ae an 3.5 — 5.50

Sheeps’ Milk.

Similar to the goats, the sheep are indigenous to mountainous
countries. It is in such countries only that sheep are kept, mainly
on account of the milk which they furnish ; so for instance, in the
Loziére, the Appenine and the Karpathian mountains. The many
points which mountain dairies and the dairies of the marshy flat
lands have in common, is also illustrated by the fact that sheep are
kept for their milk in Holland (Martiny).

Appearance: Color, yellowish-white.

45

Consistency: It is richer than cows’ or goats’ milk; the cream
rises slowly, and the bntter made from it is soft, greasy, and does
not keep well.

Odor and taste are similar to cows’ milk.
Specific gravity: 1.084 to 1.042.

Chemical composition:

Water and volatile substances......... 80.0 — 85.00
Dats wacked weee bee cetouans maser 0.5 — 1.25
Albuminates. wa ccict aides secelnewdawa aes 4.0 — 6.50
abr seiG ek tetas) a Aas alk at ada dees 4.0 —- 7.00
Ae BURA Siena sidicucewes esas seeds 4.0 - 6.00

Asses’ Milk.

Apart from the milks previously mentioned, asses’ milk is often-
est used as a substitute for breast milk, especially in France. The
properties are:

Appearance: Color, white.

Consistency: More water than any of the milks previously
described.

Taste and odor are similar to cows’ milk, but sweeter.
Specific gravity: 1.030 to 1.086.
Chemical composition:

Water and volatile substances......... 89.00 — 92.0
Dalits oid ceca ees eae ueer 0.25 - 0.5
Albuminates........ cc. cee eee cece 1.50 — 3.0
TA Wie Gui k diiins: Paice Baten Son aU eed a Gia adeseny 1.00 ~ 2.5
Milk sgaric cx oximcsewsmiwns cesennns 4.50 - 6.0

Mares’ Milk.

The keeping of mares for the purpose of utilizing their milk, is
at present practised only by some half cultivated races, and in the
kumyss establishments, where it is used for the manufacture of an
intoxicating drink, called kumyss.

Mares’ milk possesses the following properties :

Appearance and consistency: Whitish and watery, like asses’
milk.

46

Odor and taste : Similar to asses’ milk, butsweeter on account

of a frequent preponderance of milk sugar.
Specific gravity: 1.031 to 1.036.
Chemical composition:
Water and volatile substances.........

The description of other kinds of milk, apart of those already
mentioned, are of little value. The examination of such milks is
based upon the same principles as have been prescribed in the case

of cows’ milk.

4

— 92.5

0.5
1.0
1.5
6.5

47

CONDENSED AND PRESERVED MILKS,
WITH AND WITHOUT SUGAR.

Condensed Milk with Sugar.

Condensed milk and milk preserves have until lately been
prepared from cows’ milk only.

Historical remarks: It is frequently, but erroneously, stated
that Gail Borden was the inventor of condensed milk. This is,
however, not so. The process of milk condensation is a European
and not an American invention, for long before Gail Borden were
condensed milks prepared by various processes known in France.
So that of Adolphe Anaclet Nalbec (1826), Braconnot (1830),
Grimaud (1835), J. M. de Lignac (1847). Simultaneously this
subject received attention in Germany and England. Gail Borden’s
patent dates from the year 1856. He can, therefore, not be called
the inventor of condensed milk; but to him belongs the merit of
having first prepared condensed milk by a rational process and in
a practicable form. In later years this process was first employed
in the United States, but its use extended rapidly to other countries.
Switzerland, England, Germany and many other countries, possess
now establishments manufacturing this modern commodity, which,
apart of cheese and butter, is at present not only the most popular
milk-food, but one which finds more consumers from day to day.

The condensed milk containing sugar finds its way into the
market, packed in tin boxes containing from 450 to 500 grms. of
the product.

Such condensed milk, evaporated, with the addition of more or
less sugar, in a vacuum pan, contains, if the process is properly
carried out, all the constituents of the milk unchanged as far as
their chemical and physical properties are concerned ; it differs
from cows’ milk merely by having lost some of the water, and the
whole of the natural milk flavor. It is simply a prejudice that
Swiss condensed milk should, as regards richness, possess superior
qualities. Considerable stress is laid on the superior quality,

48

especially as regards flavor, of the milk of cattle fed on Alp-
mountain pasture.

If we consider, however, that the establishments which manu-
facture condensed milk are not only situated in the valleys, but use
exclusively, as they do everywhere else, milk produced in the
valleys, the ridiculousness of the claims made for the purpose of
reclame are at once apparent. These claims are equalled only by
those proffered by the manufacturers of infants’ milk-foods, who
claim that their manufactures may fully compensate for the lack
of breast milk. Provided that only good cows’ milk is used, and
that with an unvarying addition of sugar it is condensed to a
proper and equal degree, no good reason exists why condensed
milk produced in any other country should not be equal to that
produced in Switzerland.

According to the season in which this milk is manufactured, the
product differs in color. It is obtained whiter during the winter,
more yellow during the summer. Condensed to a proper degree,
it has the consistency of honey, and must, even after the boxes
have been opened, remain in good condition, without change.
Under such circumstances it should form a skin, consisting merely
of dried milk constituents and sugar crystals, while the milk
underneath should remain unchanged.

Sometimes such milk shows the consistency of cheese. This is
produced by carrying the condensation too far. It shows then,
frequently, odor and taste of rancid butter. Such milk is not
completely disintegrated by water.

Physical Analysis:

The condensed milk boxes are generally opened on that end
which is closed by one single tin sheet. For the purpose of ex-
amination, the boxes should be opened at the end where, through
a hole in the center, the milk had been filled in, and which then
had been closed by a separate cover, soldered air-tight to the box.
We do this to ascertain whether the soldering has been perfect
and has been performed without scorching the contents. To this
end the cover is removed by cutting it on the circumference for
about three-quarters.

The appearance of the milk is examined by removing some of
the contents by means of a knife or spatule, and by observing it

49

against the light while it is allowed to run in a broad sheet back
into the box.

Any imperfections, as the existence of more or less granules, of
which good milk should contain but few, can thus be observed.

A good normal condensed milk should be of the consistency of
honey ; it should possess an agreeable flavor, and must be easily dis-
integrated, without the separation of a flocculent residue, by mixing
it with from four to five parts of water. Only products prepared
by deficient processes show abnormalities.

The microscope reveals the presence of butter globules, crystals
of sugar, and groups of normal milk salt crystals.

Crystals of a moss-like structure are found in milk only when
the process of condensation has been earelessly performed.

The microscopical observation is greatly facilitated if the con-
densed milk is brought upon the slide with a drop of oil, which
will not affect the sugar crystals and salts. Cane sugar appears in
large monoclinic prisms ; milk sugar in four-sided tri-metric prisms ;
calcium lactate forms tufts of fine needles.

The specific gravity is determined in a flask of known weight
and contents, in the manner described above.

Chemical Examination,

For the determination of the solids and ash, two to three
grms. of condensed milk are accurately weighed in a covered
platinum crucible, coagulated by means of absolute alcohol, and
treated as described on page 22.

Care must be taken that the sample is perfectly free from solder.
Its presence would not only produce inaccurate results, but would
destroy the platinum crucible when the solids are incinerated.

The albuminates and the fat are determined in two to three
grms. accurately weighed in a covered beaker; 100 to 150 grms.
of water are then added, the whole mixed thoroughly and precipi-
tated with copper solution, as usual. From 1.5 to 2 cc. of copper
solution, and 0.75 to 1 cc. alkali solution are required. The
remaining part of the process of manipulation is the same as
previously described (see page 24).

The determination of the canesugar and milk sugar is made in
such a manner that the latter is directly determined by means of

50

Fehling’s solution, while the former is calculated. This method
of determination by difference may well be accepted, considering
the fact, that the rest of the constituents is determined by very
accurate methods.

Well-preserved condensed milk of commerce varies in its com-
position according to the degree of concentration, the addition
of cane sugar, and the season in which it has been manufactured.

The composition of condensed milk from different establish-
ments varies as follows:

Water and volatile substances............. 20.0 — 30.
atl bi egen ae eae ce sraes nce u cs ease) vi ghey eer ada cdeiebces ana 1.5 - 3.
EEO Geese Sart Rea oe oh heads Seale donald rh ges 8.0 — 12
Albumitiatesss «126.3 eec nek wi exe kt eee ee 10.0 — 18.
MUG UTS asus die wd eee mon woke GA 10.0 - 15.
CANS SUG sie anniiacewewesnumamen mex 30.0 — 45.

Other Milk Preserves.

Condensed milk free from sugar, which is in general use in
many large cities of the United States, where it is sold by measure
from house to house, contains :

Water and volatile substances.............. 46.5 — 55
PAUSE Sed acemausicnle sank coms deaknetget en Moreeaalworere: tong Ayo aah 2.0 - 3
Heats esis avers cease rere See ee Oh oceans 13.0 — 20
ALbUMMnates 3c aiccaac ues was beta Ra 13.5 — 27
Mil ES GOT 0 wistoctsonie cate Careuieis vaRve ree 12.5 - 18

The following specialties are also to be found in the market :
cacao milk, coffee milk, medicated milk (N. G.), malt milk (N. G.)
and salt milk, in which part of the cane sugar is replaced by salt.
This latter is said to be employed in the manufacture of oleo-
margarine.

Lately, also, an article has been brought into the market, which
is known in France as condensed Goudron milk, which is milk con-
densed with the addition of tar.

Condensed goats’ milk, prepared by Gebr. Sigmond of Klaus-
enburg, Germany, has, according to an analysis-made by Godeftr roy,
the following composition :

51

Water and volatile substances.............00 0005 20.98
PAE Bl sci vais udvorsnvarsucucoas avahs Gascsscane asia ousl nieve kesep eerie tens 3.60
CA ie gata pemarnescsh acts erm nteere Ghar stedcereesser CGA oa ade easeadadeast atta 16.95
AV DW MIM AEOS ss cae scceereracahanavaiaaja, awianaeteaade guainieeds 17.00
IMT SCAT sca sa ausmraiaea aa nee ae lusarar avatar 15.72
ate: BU AP is jocaccccaiacensversemnatshawassabasouiarneecaeenasees 25.75

Preserved milk is generally prepared by Appert’s process,
which is known for the last forty years, and which consists mainly
in boiling the milk, to destroy ferments, and keeping it then in her-
metically sealed vessels.

Some methods of preservation by the use of chemicals are also
practically employed.

The report of an analyst on the analysis of preserved milk
should state :

1. Weight of can and milk, and weight of milk net, and
if possible, the price of the article.

2. Trade mark and remarks as concerns untruthful claims
made, ete.

3. Statement as regards the burning or scorching of the
milk, when packed.

4. Consistency, color and flavor.

5. Results of the physical examination, including that by
the microscope.

6. Results of the chemical analysis, arranged as given above.

Hygienic Demands.

The manufacturer should guarantee a certain chemical com-
position. Statements giving the average values in which the con-
stituents are present, should be given with each package.

As yet, condensed milk has never been found to have been
adulterated.

52

WOMAN’S MILK.

Woman’s milk differs from the milk of animals, especially
cows, not merely as regards the relative proportions in which the
various constituents are present. There exist in some of these
constituents marked differences regarding their chemical proper-
ties. The albuminates of woman’s milk, for instance, behave dif-
ferently towards precipitants. Woman’s milk contains, according
to the latest investigations of P. Radenhausen, no casein, but albu-
men, protalbumen and peptone, as they are found in the blood.
This is the cause of the alkaline reaction of woman’s milk. The
milk loses its alkalinity, and shows then an amphotere reaction
only, when larger quantities of protalbumen occur. The butter
globules are in greater part free. With regard to these two points,
woman’s milk differs considerably from cows’ milk, which is very
rich in protalbumen. To these differences must be added, that
woman’s milk sours but slowly on account of its great alkalinity,
and that the sugar predominates over the albumen.

The keeping qualities of woman’s milk are such, that author
has kept such milk during the summer, and during the winter near
a stove, for from six to eight days before it curdled.

The appearance and composition of woman’s milk differ con-
siderably. Figures stating the composition are necessarily aver-
ages from a large number of examinations.

The secretion of woman’s milk and its composition are con-
siderably influenced by many circumstances, and more so than in
the case of animals.

L. Fleischmann (Klinik der Paediatrik, vol. 1.) mentions the
following:

1. Individual differences exert a certain but not a great influ-
ence upon the secretion and composition of the milk. Large breasts
by no means indicate that the milk secreted by them is of good qual-
ity, as has been clearly demonstrated by the milk examinations un-
tertaken by the author at the Bureau Central des Nourrices in Paris.
Lean but well-nourished wet nurses produce frequently a richer

53

milk than fat nurses. Not much value should be attached to the
color of the hair. A good healthy appearance and a happy dispo-
sition are of far greater importance.

2. Theage: Women of the age of 20 to 30 years furnish
generally the best milk.

3. The question of food, as regards its influence upon the
milk, should be considered from various points. Unaccustomed
but good food, taken for the purpose of exerting an influence upon
the secretion of milk, has rarely accomplished what has been ex-
pected, ¢. ¢., the secretion of better and richer milk. Different it is
with animals, where a change in the food, from vegetable to an-
imal diet, for instance, is at once followed by decided changes in
the composition of milk.

If, however, the consumption of food is below the normal, and
insufficient for the wants of infant and mother, either the one or
the other must suffer.

4. Menstruation: The influence of menstruation upon the se-
cretion of milk has long been overestimated. Even physicians con-
sider it their duty to forbid the continuance of nursing on its
recurrence. The examinations of Vernois and Becquerel have
proved that such milk is richer in salts, albuminates and fat, and is,
therefore, better. Only the quantity of the secretion is diminished.

5. Pregnancy: The continuance of nursing after the mother
has again become pregnant is accompanied by grave consequences.
Not only the mother and the child which she bears suffer, in conse-
quence of the greater demands made upon the mother, but also the
infant, whose supply of milk may be greatly diminished, if it does
not fail altogether. An additional danger to the nursing child has also
been found in the fact that such milk is apt to pass again through
the stage where colostrum is the natural secretion (Bouchut).
According to Davis’ examinations, the solids which the milk con-
tains are, with progressing pregnancy, gradually diminished, es-
pecially so the albuminates, fat and sugar.

6. The milk in various periods after birth is not equal in its’
composition. The first milk obtained at any one time from the
breasts is generally thinner, while the last is the richest. A few
days after birth the breasts yield colostrum, containing as yet gran-
ulated corpuscles, mucus and groups of butter globules. The

54

colostrum acts as a purgative. After the eighth day the milk ap-
pears normal to the naked eye, though it may contain a few colos-
trum corpuscles.

7, Sickness increases, in all cases, the milk solids, especially so
in cases of chronic disease.

8. The influence of all kinds of psychic emotion upon the
secretion of milk is well recognized.

9. The quality of the milk depends also on the number of
children which the mother has borne, as also on fhe age of the
previously born child, and the surroundings and circumstances of
the mother. The milk from each of the two breasts differs, also.

All these circumstances must be considered and stated, if the
examinations make claim to scientific accuracy.

10. Medicines taken by the mother may pass into the milk as
they pass into cows’ milk.

Abnormalities in milk are either caused by the lack or pre-
ponderance of one or more constituents, or by the presence of
substances not found in normal milk.

Woman’s milk has the following properties :

Smell: Hardly perceptible when from white women, but pe-
culiar, and similar to the exhalations of the skin, in the case of
women of the African race (Mott).

Taste: Sweeter than cows’ milk, occasionally salty.
Color: Bluish-opaque.

Consistency: It is more watery than the milk of animals.
Author found the milk, a few days or weeks after birth, rather
rich in fat. The fat collects often in small globules on the sur-
face ; they possess an intensely yellow color, and are of such size
that they may be seen with the naked eye.

Reaction: The reaction is, according to the latest investiga-
_tions—which embraced the examination of one hundred and fifty
samples—alkaline, provided the milk was tested directly after it
had been obtained (Conrad, L. Fleischmann).

The specific gravity ranged in 130 observations from 1.025 to
1.039, at 15° C. (Conrad.)

55

Taking the Sample.

The time when a sample of milk is taken is by no means un-
important, and, in the case of woman’s milk, presents some diffi-
culties. Herbivora give their milk generally at stated periods; in
the case of woman, however, it is different, and the taking of the
sample is more difficult. With the report on an éxact analysis,
such data, giving the details with regard to the sampling, are in-
dispensable.

Conrad proposes that the sampling be done, if possible, by the
analyst himself, to prevent intentional or unintentional delusion.
The best time for this is from two to three hours after the last
nursing, when the breasts have filled again, and are ready for
another nursing. The whole of the milk is then drawn, either by
means of a breast pump, or by the use of forefinger and thumb,
when it is collected in a clean, dry beaker. This latter manipula-
tion can, with some practice, be conducted without causing the
least pain, and is preferable to the use of the breast pump, since it
brings the milk quicker, and because it furnishes better indications
regarding the quantity of milk, and also its quality and consis-
tency. By observing if the milk flows in thicker or thinner strains,
valuable hints regarding the explanation of certain irregularities
with reference to the nursing of the infant, and its digestion, may
be obtained.

Thus, from 30 to 50 or 100, and sometimes even 200 c.c., of
milk may be obtained. For really exact investigations, the milk
from both breasts should be drawn and intimately mixed before
the examination.

Physical Examination.

The specific gravity is determined for scientific purposes by
means of a bottle of known weight and contents. For ordinary
purposes, a lactodensimeter of Quevenne, of reduced size, may be
used (Conrad’s). They allow the determination of the specitic grav-
ity in from 30 to 40 cc. of milk. The manipulation and calcula-
tion are the same as will later be mentioned in the chapter treating
on “Milk inspection.” Fora better estimation of the quality of
woman’s milk, a determination of the fat by means of the lacto-
butyrometer should be made.

56

An apparatus for this and the determination of the specific grav-
ity, neatly packed in a case and ready for use in hospitals, has been
devised by Dr. F. Conrad, and its application been described by
him in a pamphlet entitled “Die Untersuchungen der Frauen-

milch fuer die Beduerfnisse der aerztlichen Praxis,” Bern, 1880, J.
Dalp.

Microscopical Examination.

It must not be attempted to determine the quantity of fat in
woman’s milk by means of the microscope. The difficulties which
present themselves here are even greater than in the case of cows’
milk.

The butter globules are scarce on the second day after delivery,
while the granulated colostrum corpuscles predominate. Gradually
the latter disappear while the former increase, until at about the
sixth to eighth day after birth, they fill the whole field of vision
quite densely. They appear of nearly uniform size, are round and
highly refracting. The nourishing qualities of a milk depend on
the quantity of fat globules, since milk sugar and albuminates in-
crease in proportion. The presence and preponderance of very large
butter globules indicates richness in fat. Such milk is more diffi-

cult to digest. Milk which contains badly-formed globules is lack-
ing ia nourishing qualities.

1. Woman's Milk,—The butter globules at the right upper part of
the drawing appear irregularly shaped, produced
by the action of acetic acid upon them.

57

Large globules are generally observed after a protracted period
of nursing, and if the mother is advanced in age, an increase of
the size of the globules has also been observed, and is then accom-
panied by the appearance of colostrum corpuscles at the period of
menstruation, as also in cases of sickness accompanied by fever.

Very small globules predominate in the milk of insufficiently
nourished or sick mothers. The children show then frequently
symptoms indicating an insufficiency of food, as rachitis, atrophia,
anaemia, leucaemia, etc. :

Colostrum corpuscles may often appear in the milk, and betray,
generally, sickness of the mother (feverish emotion, menstruation,
etc.) If present in large numbers, they cause dyspepsia. Their
occasional appearance is of no consequence.

Woman’s Colostrum.

Blood Corpuscles are found in eases of inflammation of the
breasts, excoriation, ulceration, ete.

Pus is found in cases of abscess of the parenchym of the
glands.

Chemical Analysis.
The reaction is determined in such manner as has been de-
scribed in cows’ milk.

The methods of coagulation of albuminates and fat, as de-
scribed by Hoppe-Seyler, Tolmatschoff, Brunner, Schukoffsky,

58

Christena and others, are well known and have been sufficiently
discussed, that we may consider that our readers are sufficiently
acquainted with their drawbacks, consisting partly in very tedious
operations, partly in unreliable results. (See Fresenius’ Zezd-
schrift, 1880; Petersen’s Forschungen, 1879; Gerber und Raden-
-hausen’s Vorschlaege zu einer einheitlichen Untersuchungsmethode
der Milch, Schweizer Wochenschrift f. Pharmacie, 1879.) The
method employed by the author is a modification of the one pro-
posed by Ritthausen for cows’ milk. The albuminates of woman’s
milk differ from those found in other milks, especially, also,
in their behavior to precipitants. A few c.c. of cupric sulphate
solution precipitate the albuminates in 10 ¢.c. of cows’ milk easily
and completely, while in woman’s milk but a part of the albumi-
nates can thus be coagulated. By a modification of the process,
however, complete coagulation can be obtained. To this end
it is necessary to neutralize the acid in the sulphate almost or
completely. Thus a fine flocculent precipitate is formed, which
contains the fat and all the albuminates.

After a great many experiments the following method was
adopted :

5 e.c. of woman’s milk are diluted with 100 e.c. of distilled
water, and after mixing well 3 ¢.c. (sometimes, perhaps more) of
cupric sulphate solution are added, and then at once 2.5 to 38 c.c.
of the alkali solution (strength of the respective solutions as
given in the article on cows’ milk). A precipitate is produced
which sinks easily to the bottom of the beaker. For its further
treatment we refer to the detailed description given in the chapter
on the “ Chemical analysis of cows’ milk,” p. 24.

The determination of the solids and ashes is made in 10 c.c.
of accurately weighed woman’s milk. The particulars for the ex-
amination of this milk do not differ from those described in the
chapter on the “ Analysis of cows’ milk,” to which we refer.

The difference in the composition of the milk of white women
compared with that of women of the African race, las been
given by H. A. Mott, jr. According to his statement, the secretion
of the milk commences on the seventh or eighth day. The color
of this milk is yellowish-white, resembling cows’ milk. It is richer
in solids than the milk of white women, and, on evaporation,

59

shows a distinct odor. The colostrum is similar to that observed

with white women.

Albumi- Milk

Milk of white women. Water. Salts. Fat. nates. Sugar
Average of 14 Analyses (Tidy)..... 87.806 0.285 4.021 3.523 4.265
se 89 ** (Vernois and Bec-
Quer) eas acacsAwotsuwww anaes 88.908 0.188 2.666 3.924 4.364
Average of 14 Analyses (Simon)..... 88.360 0.230 2.530 3.480 4.820
Milk of colored women,
Average of 18 Analyses (Mott)...... 86.340 0.600 4,030 3.320 5.710
AVERAGE.
WOMEN.
White. Colored.
Specific gravity....... 1.028 — 1.035 1.025 — 1.037
Water and volatile subst $8.0 — 90.0 86.0 — 90.0
DAMS iis Sectnealtnceenareneys 9.2— 0.5 0.8— 0.75
Albuminates.......... 2.0— 4.0 18— 4.0
HAG ihe Ger nthecndecn eae 2.5— 65.0 4.0— 5.0
Mille sugar ois.0504 wae 5 40— 6.0 5.0— 6.0
Average composition of colostrum :
Wratenincccs oucateicans 80.0 — 86.0
Daltsicecity Gaavegrainan 0.8— 0.5
Albuminates........ 8.0 — 10.0
Hattivad dh sgertestendeiedeisies 2.5— 5.0
MIE SUGaT 5 <2nnes oxi 4.0 — 5.0

The reports on the results of the examination of woman’s

milk must contain the items given, and also:

1. Specific gravity.
. Reaction.

2

3. Age of woman, race, and color of hair.

4. Period of lactation ; also, if the sample examined is
from the right or left breast, or an average from
both ; quantity of milk obtained, and at what time

after last nursing ;
. How often delivered.

. Constitution.
Mother’s support.
Health of infant.

SO MARH

time of day.

. Is menstruation present, or sickness?

Weight of infant, if it can possibly be obtained.

Milk from the Breasts of Newly-born

It frequently occurs that the breasts of newly-born infants con-
tain considerable quantities of a secretion of the characteristics of
milk (Hexenmilch). Slight pressure will furnish it in single drops.
The microscope reveals the presence of real fat or milk globules,
together with detached cells and colostrum corpuscles. It contains,

60

Infants.

according to an analysis made by Schlossberger :

It has likewise been observed that men and male animals, in
rare cases, yield a secretion from the breasts, resembling milk

(Bock’s milch).

OW ater ince veers 98.750
IS ALEBi fac Suancs a csaussaches ac aeewes ake at 0.050
Albuminates.............. 0.865
Halts. arecesaeacacabsley She trsiabncitess 0.082
Milkssugatys si cnatuvesens 0.065

99.312

61

INFANTS’ MILK-FOODS

IN POWDER.

History: For the last ten or twelve years a food for infants,
called milk-food, has been inthe market. This was first prepared
by a German, H. Nestle, in Vevey, Switzerland, and consists of
prepared wheat flour and condensed milk. At the present time
quite a number of milk-food factories are in existence, mainly in
Switzerland, Germany and England, each of which works by
a method of its own. The United States possesses but one estab-
lishment, and this only since 1881, under the management of the
author.

Definition: All milk-foods are combinations of milk with
specially prepared cereals and other flours. Other preparations, as
maizena, flours of arrowroot, leguminosae, barley, rye and oats,
should be sold as such to prevent the formation of the erroneous
impression that they contain milk, and are intended as food for in-
fants.

The following substances constitute the milk-foods of commerce :

1. Water and volatile (aromatic) substances.

2. Salts, especially alkalies and earths.

3. Milk fat and vegetable fat.

4, Milk albuminates and vegetable albuminates.

5. Soluble carbohydrates: milk and cane sugar, glucose, dex-
trine and soluble starch.

6. Insoluble carbohydrates and starch.
7. Cellulose in very small quantity.
The properties of milk-food are:

Odor normal: Agreeable, pastry-like.

Abnormal only when spoiled by age or exposure; it is then
sour or mouldy. It may be decidedly rancid (tallow-like) from ex-
posure or the use of moist flour in the manufacture. A slightly
rancid odor disappears easily on boiling, and does in no way
impair the use of the food. This odor is produced by the presence

62

of volatile acids of the fatty series, and forms readily in all milk
products, especially those which are prepared with the aid of flour.

Taste: More or less sweet, mainly derived from the admixed
condensed milk.

External normal appearance : Most foods appear as a more
or less fine powder of a whitish to yellow color; lately they have
also been brought into the shape of tablets, obtained by the appli-
cation of high pressure.

Abnormal appearances: Vegetable mould and animalcule
are met with only in very old and carelessly exposed articles,
especially when it had been packed in defective boxes, or when it
had been kept in damp places.

Microscopical Examination.

This aims to recognize:

1. The general structure of the powder.
2. The butter globules of the milk.
3. Probable abnormal qualities.

The bulk of these milk-foods consists of carbohydrates which
appear differently, according to their preparation previous to the
admixture of the milk. They are either used in the ernde state, or
after being diastasized or baked.

Without going into the details of the questions of physiology
and chemistry of starch, it will be well to give a few facts relating
to this substance.

Starch heated with much water loses, already at a temperature
of from 60 to 70° C., its peculiar characteristics by which it can,
otherwise, easily be recognized under the microscope. Some kinds
of starch show after careful roasting plainer and more easily recog-
nizable properties than they possess when they are in the raw state.
In examining a starch we can, therefore, use this process for the
determination of their origin. The starch granules in bread gener-
ally retain their characteristics.

Careful heating to 100° C. increases the size of the granules.
The structure and the navel become more distinct, and the shape
becomes more round. Under the influence of a temperature of
150° C., most granules burst, and then the characteristic structure

63

disappears; those which stand the temperature without bursting,
appear then smaller ; structure and navel become indistinct and often
unrecognizable.

The starch granules from the crust of English biscuits are gener-
ally somewhat smaller than those from the center, on account of the
more direct influence of the heat upon the outside during baking.
The same is the case with bread. The straight lines marking the
strata appear, after roasting, wavy, caused by the irregular expansion
of the layers. The presence of these wavy lines, when well defined,
is decisive in the question whether the starch had been roasted or
not. Frequently it is easier to decide whether a starch had been
roasted at between 100 to 150° C., than to come to a decision re-
garding the origin of the starch.

The magnifying power of the microscope should, for these ex-
aminations, be not too small, since often minute details must be ob-
served. It is also advisable to make all observations with the same
lenses. The size of the granules is thus easier remembered and rec-
ognized, and the diagnosis thereby greatly facilitated. *

A magnifying power of from 400 to 500 diameters is sufficient
for all purposes.

Microscopical Examination for
Carbohydrates.

To prepare a sample of milk-food for examination, the fat should
first be removed from 0.5 to 1 grm.in the apparatus devised for
fat determination, and described on page 26. Some of the sub-
stance is then brought on a slide, and mixed with one drop of a
mixture of equal parts of glycerine and water. This mixture is
preferred, since in pure water the granules swell too rapidly, while
with pure glycerine no distinct picture can be obtained. Milk-food
is very finely-ground, and it is, therefore, natural that not all the
particles in the field of vision will show the required character-
istics. These can safely be neglected, and it is, therefore, only
necessary to observe such as will present sufficient characteristics
for classification. :

A microscopical examination is to be considered only as a qual-
itative,.and never a quantitative, test in the case of milk-food.

The presence of starch can also be determined by the iodine
reaction. The result thus reached is, however, too general and,

64

therefore, of little value. The characteristic forms of kinds of
starch met with in the composition of milk-foods, are the following :

SAMPLES OF STARCH AS SEEN BY MEANS OF THE MICROSCOPE.
MAGNIFYING POWER, 300 DIAMETERS.

© d23O2)

000 QPFoo¥

Starch of Wheat.

8208

Starch of Beans.

This does not exclude that other kinds of starch and flours may
be used. In exceptional cases it would, therefore, be well to make
comparisons with the cuts as given in Hager, Die pharmaceutische
Praxis; Konig, Nahrungs and Genussmittel, II. ; Hassall, Adulter-
ation of Food.

Microscopical Examination for Butter
Globules.

The presence of condensed milk in milk-foods is easily recog-
nized by the presence of butter globules. They appear under the

65

microscope as strongly refractive fat globules of varying size,
which, on account of the protection afforded by the flour, do not
easily unite, even after dilution with water.

To better distinguish them, a small quantity of the flour is
brought on the slide, and then a solution of iodine in water (1:50)
is added. Starch and dextrine are both distinctly colored, while
the fat globules assume but a very slight yellowish tint on their
extreme edge, and are easily recognized by their strong refractive
powers. It occasionally happens that even starch granules are not
colored by iodine, and may then be taken for fat globules. Addi-
tion of potash will swell these and dissolve them gradually, while
the fat globules remain unaltered behind.

Eliza MeDonogh, in her dissertation on milk-food, considered
herself justified to conclude from the absence of sugar crystals in
these foods, that no condensed milk had been used in their prepar-
ation, since this always shows sugar crystals. Miss McDonogh and
Prof. Wyss would not have come to this conclusion if they had
considered the method of manufacturing these foods, which totally
differs from that of condensed milk. They even neglected to test
these foods qualitatively for fat, and failed, on their microscopical
examination, to recognize the butter globules. Their views are,
therefore, without value. Owing to the process of manufacture,
the butter globules are very finely divided and may, therefore, be
easily taken for starch.

Beside the amylum and fat globules, the microscope will also re-
veal other normal constituents, the vegetable albumen and cellulose
fragments.

Abnormal Constituents.
As abnormal constituents, fungi and the meal-mite may be
found, which have their origin in the use of inferior flour.

Chemical Analysis.

The reaction of milk-food, after boiling with water, is acid.
This is caused by the presence of large quantities of phosphates,
and also by the presence of acids of the fatty series.

Determination of Water.

3 to 4 grms. of milk-food are taken from the center of a box

66

and accurately weighed in a previously weighed and covered plati-
num dish. They are carefully spread out by means of a spatule,
which after use must always be cleaned by means of a small brush.
They are then dried in an air bathat from 100 to 110° C., under
frequent stirring. The dish and cover are placed in a dessicator
to cool, and then weighed. This must be repeated until the weight
remains constant.

Determination of the Ash and Phosphoric
Acid.

The combustion for the determination of the ash must be carried
out at as low a temperature as possible, so that none of the more
volatile constituents of the ash are lost by volatilization. It is best
to operate as follows: The whole is heated to complete carboniza-
tion of the contents, which are then transferred to a porcelain dish
and extracted with water. The solution is then filtered off. The
filter and the residue upon it are then again transferred to the
platinum dish and, after drying, incinerated. The water solution,
unless it be preferred to determine it separately, is then, together
with the ashes, evaporated to dryness, then heated to a dull red
heat, and allowed to cool in a dessicator. It is then weighed.

The determination of the phosphoric acid is carried out after
the manner described on page 238.

Determination of Fat.

Some of the milk-food from the center of the box is placed
into a dry stoppered test tube, which is weighed. From 2 to
3 grms. are then brought upon a dry filter resting in a small fun.
nel. The tube is then re-weighed, the difference being equal to
the quantity placed upon the filter. The funnel, with contents, is
then dried in an air bath, at from 80 to 100° C., for a short time,
to remove the bulk of the moisture. Filter and substance are then
transferred from the funnel to the funnel belonging to the appa-
ratus described by the author for the determination of the fat.
This funnel is then adjusted to the weighed flask, and ether, free
from alcohol, is poured upon the filter, care being taken that none
of the food is carried over the edges of the filter. When the flask
is about half filled with ether, the apparatus is connected, and the

67

flask heated so that the filter is continually immersed to about one-
half its height in condensed ether. The complete extraction of
the fat requires from one to two hours’ treatment. The ether is
then carefully distilled off, the last traces being removed by heat-
ing in an air bath at from 100 to 110° C., while the flask is placed
into a horizontal position. After cooling in the dessicator, the
flask is weighed, the increase corresponding to the amount of
fat contained in the quantity of sample taken.

Determination of the Soluble Carbo-
hydrates.

In the determination of the soluble carbohydrates, it is of im-
portance that the directions for use, as established by the manu-
facturer, should be carefully considered. The manufacturer’s
claim in regard to this is fully justified by the fact that more sol-
uble carbohydrates are contained in the food after its preparation,
according to the directions, than are contained in the food previous
to such preparation. The value of an analysis which gives the
composition of the food as it is employed, is, likewise, the only
guide which a physician has for the determination of the value of
a milk-food.

In the case of milk-foods containing diastase, we take 1 part of
milk-food and 10 parts of distilled water, and treat this mixture
carefully according to directions. In other respects, the method
of analysis is the same as for other milk-foods.

In the case of ordinary milk-foods, we take for 1 part 10 parts of
water, or for from 2 to 3 grms., the ordinary quantity taken, from 20
to 80c.c. water. The mixture is then heated to boiling, and kept
boiling for five minutes with continual stirring. It is then allowed
to cool. This process should be accelerated by blowing and stirr-
ing, to prevent the formation of askin on the surface. This part
of the operation is best carried out in a porcelain or platinum dish,
which should be large enough to conveniently hold the double
quantity of the fluid used. After cooling, the contents are trans-
ferred to a beaker of 150 to 200 cc. contents, the material adher-
ing to the sides of the vessel being carefully washed with 100 c.c.
alechol, of 50° Tr., into the beaker, so that the sediment therein
is not disturbed. The whole is allowed to stand over night. The
clear fluid is then first drawn off by means of a siphon and filtered
through a dry filter. Finally the precipitate is washed on the filter

68

with 100 cc. aleohol of 50° Tr. The filtrate is thus brought to
about 220 ¢.c. It is then carefully evaporated on a water bath to
about 50 ¢.c., refiltered, when necessary, and finally evaporated to
dryness in a weighed platinum dish. The drying is finished in an
air bath at from 100 to 110° C., and is to be continued until no
further loss of weight is observed. To facilitate the drying, it is
well to add to the solution, which has been concentrated to about
10 c.c., some absolute alcohol from time to time, whereby the carbo-
hydrates are precipitated, and then to spread the mass over the sides
of the dish by means of a spatule. Evaporation is thus greatly accel-
erated. When constant weight has been reached, the contents of
the dish are incinerated, and, after deducting weight of dish and
ashes from the weight first determined, we obtain the weight of
the soluble carbohydrates.

Determination of Insoluble Carbohydrates.

The residue from the alcohol treatment is transferred into a
flask of 400 c.c. contents, and then 200 ¢.c. of water and 20 c.c.
pure hydrochloric acid are added. Loosely covered with a cork,
the flask is inserted into the water of a boiling water bath, and
kept there for from three to four hours. The inversion will be
completed by this time. The contents of the flask are then care-
fully neutralized, whereby any albumen which may have gone into
solution under the influence of heat and acid,is precipitated. The
neutralized solution is then filtered through a ribbed filter, flask
and filter being washed until the filtrate measures 500 ¢.c. The
amount of sugar in this solution is determined by Fehling’s solu-
tion as previously described. for the calculation of starch,
Sachsse’s figures, 108 glucose — 99 starch, have been accepted.

CALCULATION.

Supposing that 2.093 grms. substance had been used for the de-
termination of solnble and insoluble carbohydrates, and that, of the
sugar solution obtained by inversion, 28 ¢.c. had been required for
5 cc. Fehling’s solution, we would find the starch by the following

equations :
98 : 0.025 — 500 : X or KX = 0.44
108: 99 = 0.44 : KX or X = 0.408
2.098 : 0.408 — 100 : KX or K = 19,24

per cent. of insoluble carbohydrates (ainylum).

69

Cellulose: A method for the accurate determination of cellu-
lose is not known. For practical purposes, it is generally sutficient
to estimate it as being present to the extent of 0.5 per cent.

Determination of the Albuminates.

It has been customary to calculate the albumen and albumi-
noids in milk-foods by determining the nitrogen. The figure ob-
tained for nitrogen was then multiplied by 6.25, it having been
accepted that the nitrogenous part contained 16 per cent. of nitro-
gen. This presumption is false. The nitrogenous substances go-
ing into the composition of milk-food contain from 15.5 to 18.5
per cent. of nitrogen. From this it is evident that results reached
by the determination of the nitrogen cannot be accurate, and it is,
therefore, useless to speculate as to the method, which in this case
is to be preferred, Dunas’ or Will-Varrentrapp’s. For all the other
constituents sufficiently accurate methods exist. Albumen is,
therefore, here as in the case of condensed milk, determined by
difference.

Reports on Milk-foods.

must contain :

General description: Gross and net weight of packages, their
suitability, and, if possible, the price. ‘

Description of trade mark: Remarks on fancy claims upon
the labels, as would be, for instance, the claim of a complete sub-
stitute for breast milk, ete.

Physical description: Appearance, odor, taste, microscop-
ical examination.

The chemical analysis should state:

Water and volatile substances.

Salts (phosphoric acid).

Fat.

Albuminates.

Soluble carbohydrates.

Insoluble carbohydrates.

Cellulose.

Statement giving the analytical method by which these results
were obtained.

70

Hygienic Demands of the Manufacturers of
Milk-foods.

The German society, “ Fuer oeffentliche Gesundheitspflege,”
has rightfully demanded that each manufacturer of milk-food shall
attach to each package of his food an analysis stating the average
quantities in which its constituents are present. It would be very
desirable if the sanitary authorities of all countries would adopt
and carry out such measures for the benefit of the health of infants,
who depend upon this food. Why should the manufacturer of
milk-food not be held equally responsible as dealers in milk and
other food substances ?

The various milk-foods in the market vary in composition as
follows:

Average.
MGR ssi oss ena Bans 5.0 to 10. per cent. 7.50
Dal taicccc-vreunn eealeians 15to 3 “ 2.25
a beeches ws Mee ccareceemeednd 4.0to 7. 5.50
Albumen........... 95to18 13.25
Sol. carbohydrates.... 85.0 to 55. =“ 45.00
Insol. ee ... 15.0 to 35. “ 25.00
Cellulose............ 05to 1 “ 0.75

99.25

From this it is evident that the various brands of milk-food
vary considerably. The greatest variations among solids exists in
the albuminates and insoluble carbohydrates, which differ in the
first almost, and in the second over, 100 per cent. This is, no
doubt, a considerable difference, and must greatly influence the
prosperity of the infant depending on these foods for nourish-
ment, as it should the buyer, who, in most cases, will have to pay
the same price, be the food a good or an inferior article.

This desired interference of the sanitary authorities is, however,
not meant as consisting in the upholding of ideal desires, which
practically cannot be realized. What is wanted is a food which in
its composition, ze, the relations of the constituents, resembles
breast milk, and which is distinguished by its stability.

In considering what has practically been done in this field of
manufacture, we can safely say that the possibility of the solution

71

of this problem has practically been proved by some manufacturers
in Switzerland and Germany. It is also a fact that vow even bet-
ter preparations are in the market than correspond to the average
composition given above.

In the face of these facts, it is astonishing that the milk-food
of least rational composition, Nestle’s, is yet the one which phy-
sicians generally recommend. Analyses of five chemists: F. Hof-
mann, J. Konig, Miller, P. Radenhausen and N. Gerber, give for
the same, on the average, the following composition :

Average of
: Nestle’s. all Milk-foods.
‘Wistert? ssaaaden ese iuciedeties 6.74 7.50
Salt@acuitrracemcnda Gevees 1.77 2.25
ab iscdochn toch eecamcndratiadseisc dere 4,20 5.50
Albuminates............... 9.75 18.25
Carbohydrates ............. 76.92 70.00

The difference in the most important factor, the albumen, is
sufficient to show the great improvements made by others.

Author considers it of vital importance that a rationally com-
pounded infants’ milk-food should contain at least

2 per cent. salts,
5 per cent. fat, and
13 per cent. albuminates,

and that manufacturers should be compelled to adopt this standard.

Practice has taught that such milk-foods can be manufactured.
Careful investigations have proved that, for a rational food, it is
of greater importance to adhere to a certain proportion of albu-
men, fat, and salts, to the carbohydrates, than to consider the
shape in which these carbohydrates are presented. It is for this
reason that the author is in favor of the relations of the main con-
stituents as they have been given above.

Indigestion with children will increase, when a food is lacking
in albumen, but contains, in its place, soluble carbohydrates; the
first is, therefore, of greater importance than the latter.

If a sanitary governmental control of milk-foods should be in-
troduced, as it has been done already for milk, it is evident that
each manufacturer will be compelled to work better and on a more
rational plan, than is frequently done at the present time. It is

72

then to be hoped that the expressions of Albu, of Berlin, and
Jacobi, of New York, to the effect that these manufacturers work,
not for the welfare of mankind, but for their own purse, will
cease to be true.

It is evident that these two physicians do not value the com-
bined efforts of chemical science and capital very highly; yet those
who think differently should be on their guard, that they do not
allow themselves to be blinded by either reclame or fame of manu-
facturers who have failed to adapt their products to the progress of
our knowledge.

The packing of the article should be such that it reaches the
market in good condition in every respect.

If, on the statement of physicians or sanitarians, the article is
found to be not in a perfect condition, the manufacturer ought to
be notified before the results of such inspection are made public,
since it frequently happens that these preparations are not stored
with those precautions which are required to insure that they reach
the consumer in a good state.

73

GOVERNMENTAL CONTROL OF THE
MILK SUPPLY.

The question of how the milk supply of cities should be
brought under government control, has of late so frequently been
discussed, that we propuse to give here merely fundamental expla-
nations, but based upon extended experience of the matters con-
nected with the hygiene of milk. The milk reaches our markets
in a variety of conditions; sometimes it is the natural product ;
sometimes it has been skimmed or watered; sometimes botli pro-
cesses have been resorted to; sometimes the milk is fresh, good-
flavored, and shows good keeping qualities; but frequently it is
stale, of bad taste, and apt to get sour. The vessels used for
transporting it are not always the cleanest, and often no precau-
tions are taken to keep it cool while it is transported or stored.

For these reasons, it is not to be wondered that the inhabitants
of cities do not use this otherwise excellent food to such an extent
as they should and might, if they had the guarantee that only a
rich, cleanly-treated, well-flavored, and unchanged milk would be
offered them.

Milk is a product of rather complicated composition ; and it is,
by no means, an easy task to ascertain the quantities of the valu-
able constituents which it contains. It is, therefore, of the great-
est importance to the inhabitants of especially the larger cities to
know that the products which reach the market have to pass sani-
tary inspection.

In most of the larger cities, this control has been assumed by
the government ; but it is frequently carried out, not only in an
unrational, but also a very superficial manner. Science and justice
are certainly not furthered when, even now, milk is passed or con-
demned inerely upon the results obtained by the use of the lacto-
densimeter alone, or in combination with a cremometer. While
many dealers, by the use of such primitive methods, have escaped
the deserved punishment, others, who were entirely innocent, have
been punished. It is, therefore, at the time, and, in the interest

74

of sanitary welfare, that the composition of a normal milk be de-
fined, for the purpose of establighing a sure guide for rational
milk inspection.

It is our purpose to establish such points as may be deduced
from many years’ practical experience and a strictly scientific treat-
ment of the entire subject.

To pronounce a milk as good, bad, or adulterated, can, doubt-
less, be done only by regarding special laws, which must be ob-
tained by careful observation and thousands of examinations, in-
cluding the different races living under varying circumstances in
various countries, and under the influence of different climates.
But despite this well-acknowledged requirement, we meet every-
where with the passage and promulgation of ordinances which are
in direct opposition to this only rational plan. Such ordinances,
therefore, not only cause the drawing of false deductions, but, also,
the use of more serious adulterants.

This wrong is frequently committed by professors and others,
who, proud of their general learning, are frequently ignorant even
of the most exact methods of analysis, or of the latest investiga-
tions regarding milk, or the practice of dairy industry. The dairy
industry and governmental milk control require, at the present
time, as well specialists as there exist in other branches of applied
chemistry.

It is the practical specialist, and not the professor, who must de-
cide in cases before the courts. In the examination of milk, it must
always be considered that a difference exists between milk, in its
physiological bearing, and market milk; for while, in the first, the
constitnents may be present in greatly varying proportions, we
may demand, in the latter, a maximum and minimum quantity of
the whole, and all the single food substances which constitute milk.

The question how a market milk—which is generally the yield
of several cows mixed—may vary, has, for many localities, not yet
been determined. It is, therefore, of importance, when it is con-
templated to introduce government control, that the milk of many
cows and whole dairies be frequently examined, so that, for these
localities, average figures may be obtained, which may serve as a
guide. Average figures should, however, be only calculated from
such examinations as comprise the yield of whole dairies, and not
only examinations which are made of the milk of single cows.

75

While, as yet, the average figures obtained by the examination of
the mixed milk of cows supplying one dairy, has, in all countries,
been the same, we find frequently in the milk of single cows great
abnormalities, caused by the influence of race, age, constitution,
food, time of milking, heat, quantity, season, or whether the cows
are on pasture or housed.

Another desideratum of importance is the method by which
analytical results are obtained. They must naturally be exact, and
the examinations must be continued for a considerable time, care
being taken that physiological and pathological data are carefully
noted. This is, unfortunately, frequently omitted.

To facilitate a control of the market milk, on the part of the
authorities, it becomes, therefore, necessary that the limits of com-
position of a normal milk, and its physical properties, be defined,
in order to avoid reproach and tedious explanation. To fix such
limits is, however, not without danger. If we ask too much, we
risk that unjust sentences are administered, and, moreover, that
the judge will be tempted to be exceedingly lenient in such cases.
If we lower the standard too much, we risk that adulterations of
minor extent escape punishment.

Our own standard, which is based upon thousands of examina-
tions made by various investigators, and which has been practically
proved as good and just, will be given further on.

It has previously (see page 39) been stated that the adulteration
of milk may be practised by the following means :

1. Addition of water.

2. Skimming.

3. Skimming and addition of water.

4, Mixing of skimmed milk with whole milk.

5. Addition of foreign substances, to prevent detection of milk
adulterated by any of the processes in 1 to 4.

Watering and skimming, and the mixing together of such de-
teriorated products, or the mixing with whole milk, are the ordi-
narily practised means of adulteration. Other substances than
water are rarely employed, and then only when it is intended to
re-establish a normal appearance of milk which has either been
adulterated or which is naturally inferior. The substances used
for this purpose have been enumerated on pages 41-48, where
also the methods are given by which they may be detected.

76

The so frequently praised microscopical examination is of little
value unless it be for the determination of foreign substances, as
blood, pus, colostrum, detritus, ete., or solid adulterants. For the
determination of the percentage of fat, it is without value, though
it is correct, that a milk shows the butter globules in all the sizes
as they are recognized to occur in normal milk, but further apart,
when it had simply been watered. The want of the larger and
medium-sized globules may indicate skimming, since the larger
globules are known to rise sooner and easier. They are the first
to form the cream, and disappear, therefore, with the removal of
this first-formed cream.

The greatest difficulty exists in getting uniform samples for
microscopical examination, as was first shown by Conrad, who has
proved that, in examining woman’s milk, even the same sample,
carefully mixed and sampled by an arrangement to control the
quantity taken for one slide, will give results showing differences
in number, size and distribution of the fat globules. The methods
used for estimating the number of globules are, moreover, arbi-
trary and uncertain. We will later on give a more satisfactory
method for the determination of fat.

Determination of Specific Gravity.

The specific gravity of milk depends upon three points: The
substances, as milk sugar, salts and albuminates, dissolved or con-
tained in the water which forms part of the milk, in a diffused,
gelatinous condition, increase the specific gravity, while the sus-
pended fat globules diminish it. Increase of temperature dimin-
ishes the specific gravity likewise, while decrease of temperature
will increase it. The specific gravity is determined, for practical
purposes, with sufficient accuracy, by the use of a milk areometer,
the so-called lactodensimeter.

It should be remarked here that the name dactometer, which
has been given to these instruments, 7s wrong, and should cer-
tainly not be used by scientifically educated persons. It conveys
a wrong impression ; for, to this day, we have no instrument, and
least in the lactodensimeter, which furnishes us a direct measure
for the quality of the milk.

The best and most exact instruments are those of Quevenne,
the inventor of the lactodensimeter, which give, in abbreviated

17

figures, directly the specific gravity. All other instruments, with
scales differing from this, have been abolished on the European
continent. It is only in England, and through English influence
in America, that instruments with arbitrary scales are as yet in
use. The principle upon which these are constructed is a wrong
one, and they possess, moreover, useless appendages. It is never
required to use the lactodensimeter for degrees below a specific
gravity of 1.015, and all those degrees below this are, therefore,
useless. The scale appears long, but its actually useful part is ex-
ceedingly short.

Quevenne’s areometer has, for the specific gravities of from
1.015 to 1.040, on a scale of 5.5 em. length, 25 degrees, and
allows thus easily the reading of half degrees; while a so-called
lactometer has, on a scale of 7.8 ¢.m., 120 degrees, with a space of
0.065 e.m. for each degree. For milk, this subdivision lays below
the actual possibility of accurate reading.

The reason that such areometers, with arbitrary scales, have
remained in use for so long a time, is explained by the fact, that men
without intimate knowledge of the subject, and without desire to
obtain it, find it easier to go on with their investigation by making
a so-called authority responsible for their results, without consider-
ing that many of these so-called authorities frequently adhere to
and defend their wrong positions, even after they have been
proved to be untenable.

Another drawback for the practical application of those lacto-
meters is to be found in the fact that no tables exist for the correc-
tion of the error created by the reading of the instrument at a
temperature which is not the normal temperature. Every sample
must be cooled or warmed to 60° F. The usefulness of the in-
strument is thereby considerably lessened.

Description of Quevenne’s Lactodensimeter.

The lactodensimeter of Queverne is an ordinary areometer.
It is made of glass, and is 22 ¢.m. long. It consists of a hollow
body, kept in an upright position by a weighted globe at its under
end; above, it carries the 6c.m. long stem which bears the scale.

78

The dimensions of the instrument are chosen to insure sufficient
ease of motion and to prevent unnecessary length of stem.

sim aly Sle Bl* Sie

Ble Ble Bie Ble Sle

———$—$.-—

ee

SS
Centesimal Galactometer, or Lactometer. Quevenne’s Lactodensimeter.

It is weighted to such an extent, that it sinks in a salt solution
of 1.042 specific gravity, at 15° C., to a point which is marked 42.
Milk mixed with half its volume of water has a specific gravity
of 1.014 to 1.016. Therefore, a second point is determined by
putting the areometer in a salt solution of 1.014 specific gravity,
at 15° ©. This point is marked 14. The space between 14 and
42 is then divided by lines in 28 equal parts, or degrees. The dis-
tance between each two degrees is about 2 m.m. It is, therefore,

not difficult to read the specific gravity easily to 0.0005 with suf-
ficient accuracy.

79

The lactodensimeter of Quevenne-Miiller bears the scale in a
brass tube, and is, therefore, preferred by those who find the work-
ing with glass instruments unprofitable. It bears two scales—the
one to the right to be used for whole milk, and the one to the left
for skim milk.

The meaning of the fractions on the right — vs (29 — 26), vo
(26—23), ete.—is that the addition of water to whole milk is about
as corresponds to these fractions. On the left of the scale the
same is repeated, but the fractions appear in different places, 82.5 —
36.5, corresponding to normal unwatered skim milk. The fractions
on the left stand about 4 degrees lower on the scale, for the reason
that the specific gravity of milk gains 4 degrees by the process of
skimming.

This double scale allows of a far more extended application
of the lactodensimeter than those which only give the specific
gravity.

It would, perhaps, be even better to construct the densimeters
with a scale ranging from 1.020 to 1.040, and divide these 20 de-
grees over the space occupied by 28 degrees. The reading of
subdivisions of degrees would thereby be greatly facilitated. This,
from a practical point of view, is easily justified by the fact that,
in doubtful cases, at any rate, all milks showing specific gravities
outside of the limits 1.027 to 1.033, must be analyzed.

It is, likewise, to be recommended to have the thermometer
inclosed into the areometer, as is done with those which are manu-
factured in Germany.

Each lactodensimeter must be carefully examined for its accu-
racy, by comparing the results obtained with it with those obtained
by means of a specific gravity bottle, and only instruments giving
correct readings for at least three decimals should be employed.

Determination of the specific gravity: The apparatus neces-
sary for this are:

1. A well adjusted and examined lactodensimeter of Quevenne,
with or without inclosed thermometer.

2. An accurate Celsius thermometer.

3. Glass cylinders sufficiently high and wide to admit of the
introduction and use of the lactodensimeters.

80

A.— Examination of whole milk and market milk; 1. The
milk is well mixed and poured into a cylinder, care being taken
that the milk runs slowly down its sides, by holding it in a some-
what inclined position. Thus the formation of foam, which would
materially interfere with accurate readings, is prevented.

2. The thermometer remains in the milk for abont two minutes
before the temperature is quickly read and noted. If the milk be
fresh from the cow, it should be cooled by holding the cylinder
containing it in cold water. The thermometer is thereby used for
stirring the milk slowly, and for observing the gradual reduction
of temperature, which is brought as near as practicable to 15° C.
(59° F.) If, on the other hand, the temperature of the milk, as
during winter time, is very low, it must be gradually raised to
from 15 to 20° C.

8. The stem of the lactodensimeter, which bears the scale, is,
to prevent adhesion and to enable a more accurate reading, drawn
between the closed lips, and then inserted into the milk until its
surface reaches the degree marked 30. It is then liberated to find
its level. If it should swim without changing its position, it is
pushed from one to two degrees deeper, and again liberated to find
its level. If the same reading is obtained, the degree is noted.

4, All readings of the lactodensimeter give accurate density
only at a temperature of 15° C. Warmer milk is lighter; colder,
on the contrary, heavier. If the density has been observed at an-
other temperature, the actual density is found in the following
first table for whole milk, by using it in the following manner :

The first vertical column of figures gives the degrees of the
lactodensimeters read directly. The first horizontal line gives the
degrees of the Fahrenheit thermometer, the second the correspond-
ing degrees on the Celsius thermometer. In order to find the real
density, we pass froin the degree of the lactodensimeters read, to the
right, until we reach the column headed by the degree of tempera-
ture observed. The figure at the intersection of both lines gives
actual density at 15° ©. If, for instance, we found 28° on the
lactodensimeter, at 18° C., we would thus find actual density at
15° C. = 28.6° —to a specific gravity of 1.0286.

DEGREES OBSERVED ON THE LACTODENSIMETER.

TABLE FOR THE CORRECTION OF ERROR CAUSED BY THE READING OF THE LACTODENSIMETER AT OTHER TEMPERATURES THAN 15° C,
FoR WHOLE (NoT SkimmED) Mixx.

TEMPERATURES.

21
23

24
25

33

32.0 | 33.8

O|1

12. giz. 9
18.9118.9
14.914.9
15.9'15.9|
16. o16. 9

17. ny 8
sishic (cdl
19. 6

20. 6,20. 6
21 slise 5

23.3'28.8
24 324.3
95.2'25.8
26.1/26.2
27.027.1
27.9)28.0
28.8 28.9
29.7,29.8
30.6 80.7

31.5 31.6

32.4 32.5

37.4 | 39.2

35.6 41.0
21'3|)4)5

42.8
6

44.6

%

46.4

8

48.2

9

50.0

51.8

10/11

53.6

12

55.4

13

57.2 | 59.0

14/15

60.8

16

62.6

17%

12.9 913. 0113. 013.1
18. 9 14. 14. 014.1
14. 915.0 015. 015.1
15.9 16. 16. aie
16.9117.0 17.017.1
17.8 17.9]17.9/18.0
18.7118.8 18.8 18.9
19.7.19.7/19.7)19.8

20.7'20.720.7'20.8

21.621.7 |
22.5 22.6 22.7/22.8
23.4 23.5123 .6 23.7

24.4'24.5124.604.7

|
|
25.4 25.5 25.6
i}
oe 6
lay. 6

26.3 26.4
Q7.2.27.3127.427.5

28.1 28.2:28.8 les. 428.5
20.0.29.1 29.2 29.8.29.5)
29.930 0.30.1/30.330.4
30.8 30. oat. 031.231.381.4
81.7/81.8,81.9 22. 182.2 2:32.33

82 ..6/32. 732.8 8 33.0 33. 1's. 2

13.1
14.1
15.1
16.1
17.1
18.1
19.0
19.9
20.9
21.9
22.9
23.8
24.8
25.8
26.7

|
|

17.1
18.1
19.0
20.0
21.0
22.0
23.0
23.9
24.9
25.9
26 8
27.7
28.6
29.6
30.5

13.1'13.2
14.1142
15.115.2
16.1 16.2

17.2
18.2
19.1
20.1
21.1
22.1
23.1
24:0
25.0:
26.0
26.9
27.8
28.7

29.7
30.6
6

a

13.3
14.3
15.3
16.3
17.3
18.3
19 2
20.2
21.2
22.2
23.2
24.1
25.1
26.1
27.0
279
28.8
29.8
30.8
31.8
5182.7
33.6

|

13.4/13.5
14.414.
15.4115.5

16.4

17.4
18.4
19.3
20.3
21.3
22.3
23.3
24.2
25.
26.2
27.1
28.1
29.0
30.0
31.0
32.0
32.9
33 8

16.5
17.5
18.5
19.4
20.4
21.4,
22.4
23.4
24.3

225.3

26.3

27.2:

28.2,
29.2
30.2
31.2
82.2
33.1

34.0,

64.4

18

66.2

19

68.0 ; 69.8

20/21

71.6

22

73.4

23

135.2 117.0

78.8

26

80.6

27

82.4

28

84.2

29

14.2
15.2
16.3
17.8
18.3
19.8
20.8
21.4
22.4
23 .2/23.4
24.3/24.4
25.2.25.4

14.1
15.1
16.1
17.1
18.1
19.1
20.1
21.2
22.2

13.6
14.6
15.6
16.6
17.6
18.6
19.5
20.5
21.5
22.5
23.52
24.5
25.5
26.5
27.4
28.4
29.4
30.4
31.4
82.4
33.3
34.2

13.7
14.7
9
16.7
17.7
18.7
19.6

13.8|14.0
14.815.0
15.8 16.0
16.8)17.0
17.8.18.0
18.8119.0
19.820.0
20.821.0
‘21.8'22.0
22.8123.0
23.824.0
24.6 24.8 25.0

25 .6,25.8:26.0126.2°26.4

les
| |

be ieee |
-6 26.8,

27.0(27.2 27.4

|
27.6 27.8 28.0)28.228.4
iain bana ike 29.2.29.4
29.6 29-8, 80.0/380.2 80.4

30. 6130. 831. 0)31.231.4
31.631. 8.82 .0]82.2.32.4
32.6'52.8 38.033.2 38.4
33.5 /35.8'34.0184.2'34.4

34.4134. 7135,0185.2'95.4

14.4
15.4
16.5
17.5
18.5
19.5
20.5
21.6
22.6
23 .6|23.8
24..6/24.8
25 6.25.8
26.6/26.9
97.6279
28.6.28.9
29.6 29.9
30.6'30.9
81.7/82.0
32.7;38.0
33.7/34.0
34.7/35.0

14.6
15.6
16.7
17.7
18.7
19.7
20.7
21.8
22 8

35.7/86.0

14.815.0

15.816.0

16.917.1
17.918.1

18.919.1

|

19.9 20.1

20.9 21.1

22.0 22.2

238.0.23.2

24.0 24.2

25.0,

26.0
27.1
28.2
29.2
30.2
31.2
32.8
38.8
34.3
35.8

36.3

25.2
26.2
27.3
28.4
29.4
30.4
31.4
32.5
33.6
34.6
35.6

36.6

15.2
16.2
17.3

15.41
16.4
17.5
18.318.5
19. 319.5
sealing
1.321.5

|

|

22.4 22.6
23.4 23.6

24.4 246,24.
25.4.25.6

26.4:26.6
27.597.
28.6.28.8
29.6.29.9
30.6'30.9
31.6131.9
82.7188.0
38.8 34.1

35.9 36.2

34.9'85.2
|
I

36,937 .2

15. 615. 8

16. 6
ai. a
18.7

19.7|19.9
20. bias 9
21. ret. 9
22.8 23.0

23.8

25.826.
26.8 27.1
27.9,28.2
29 .0,29.8

30.1
81:2
32.2
33.8
34.4
85.5
36.5
37.5

16.8
17.9
18.9

24.1
8.25.1

80.4
31,5
32
33.6!
84.7
85.8
36.8

16.0
17.0
18.1
19.1
20.1
21.1
22
23.2
24.8
25.8
26.8
27.8
28.4
29.5
30.6
31.7

5/32.7/

33.8
34.9
36.0
87.1

37.8

38.1

16.2
17.2
18.3
19.3
20.3
21.3

122.3

23.4
24.5
25.5
26.5
27.5
28.6
29.7
30.8
31,9
33.0
34,1
35.2
36.3
87.4
38.4

16.4,
17.4
18.5
19.5
20
21.5
22.5
23.6
24.7
25.7
26.7,
27.7
28,9
30.0)

31.1]

32.2
33.8
34.4
85.5
36.6
37.7
38.7

16.6
17.6
18.7
19.7

-5/20.7

21.7
22.7
23.8
24.9
26.0
27.0
28.0
29.2

30.8)
31.4

32.5
33.6
34.7
35.8
36.9
38.0
39.1

; *
TABLE FOR THE CORRECTION OF ERROR CAUSED BY THE READING OF THE LACTODENSIMETER AT OTHER TEMPERATURES THAN 15° C
FoR SkimmMeD MILK.

TEMPERATURES.

.

33.8

1

35.6 | 87.4

2

89.2

41.0

5

42.8

6

44.6

%

46.4

8

48.2 | 50.0

9/10

51.8

11

53.6

12

55.4

13

57.2

14

59.0

15

17.2
18.2
19.2
20.2
21.1
22.0
22.9)
23.8
24.8
25.8
26.8
27.8
28.7
29.7
30.7
31.7
32.6
33.5
34.4
35.4
36.3
37.2

38.1

17.2
18.2
19.2
20.2
21.1/21.1
22.0,22.0
22,9192.9
28.823.8
24,8 24.8

|
25.825.8
|

17.2
18.2
19.2
20.2

26.8.26.8
27.9.27.8
28.7/28.7
29.7,29.7
20.7,80.7
31.7381.7
32.6'82.7
33.5'33.6
34.5/34 6
35.5'35.6
36.4|36.5
37.3)87.4

38 .2/38.3

17.2
18.2
19.2
20.2
21.2
22.1
23.0
23.9
24.9
25.9
26.9
27.9
28.8
29.8

30.8'30.9

31.8
32.8
33.7
34.7
35.7
36.6
87.5

38.4

|

1Z8
18.8
19.8
20.8
i. 3
22.2
23.1
24.0
25.0
26.0 26.1
o7.0.27.1
28.0128. 1
28.9'29.0
29.9180.0

31.0
21.9188,0

|

17.3
18.3
19.3
20.3
21.3
22.3
23.2
24.1
25.1

32.9/82.9
38.8/33.8
34.8|84.8
35.8|35.8
36.7/36.8
37.6/37.7
38.5'38.6

17.3
18.3
19.3
20.8
21.8
22.3
23.2
24.1
25.1
26.1
27.1
28.1
29.0
30.0
31 0

|
|
|

17.3
18.3
19.3
20.8
21.3
22.3
23.2
24.1
25.1
26.1

30.1
31.1

32.032.1

33.0:

33.1

33. ing 0
34.9 35.0

35.9
36.9

36.0
37.0

37.8 37.9

38.7

|

38.8

17.4/17.5

18.4|18.5

19.4|19.5
20.420.5
21.4'21.5
22.4'22.5
23 3'23.4
24.9'24.8
25 2125.8
26.2'26.8
27.2127.8
28.2,28.3
0.220.
30.2:30.3
31.2/81.8
32.2/32.8
33.2|33.8
34.1134.2
85.1135.2
36.1/36.2
87.1|87.2

38 .0/38.2

88.9/39.1

17.6
18.6
19.6
20.6
21.6
22.6
‘aaa
24.4
25.4
26.4
27.4
[pee
29.4
30.4
31.4
32.4
33.4
84.3
35.3
36.3
87.3
38.3
39.2

17.7
18.7
19.7
20.7
21.7
22.7
23.6
24.5
25.5
26.5
27.5
28.5
29.5
30.5
31.5
32.5
33.5
34.4
35.4
36.4
37.4
38.4
39.4

19.8

17.8
18.8

20.8
21.8
ao
23.7
24.6

22.9

28. sling 0
29. “629.8 830. 0
30. 6'30.8. 831.0
31. pt. 8'32.0
32. HG ses 833.0
33.6 33. 8'34.0
34.6134.8'35.0
35. 6'35.8'86.0
36.6 \36.8/87.0
37 .6)37. 8's8.0
38.6/38. also. 0

39 .6/39. ala. 0

60.8

16

18.1
19.1
20.1
21.1
22.1
23.1
24.1
25.1
26.1
27.1
28.1
29.1
30.1
31.2
82.2
33.2
34.2
35.2
36.2
87.2
38.2
39.2

40.2

62.6

17%

18.2
19.2
20.2
21.2
22.2
23.2
24.2
25.2
26.8
27.8
28.8
29.8
30.8
31.4
82.4
33.4
34.4
35.4
36.4
87.4

88.4

|
|

39.4
40.4

64.4

18

66.2 | 68.0 | 69.8

19/20\21

71.6

22

73.4

23

75.2

77.0

2425

78.8

26

80.6

27

84.2

18.4
19.4
20.4
21.4
22.4
28.4
24.4
25.4
26.5
27.5
28.5
29.5
30.5
31.6
32.6
33.6
34.6
35.6
36.6
37.6
38.6
39.6

40.6

18.6 18.8,18.9
19.6 19.8 19.9
20.6 20.8 20.9
21.621.8.21.9

22.6 22..8'22.9

28.6 .28.8.28.9
B4:0 @2-8 24.9
sits saeasl aeed
26.7 26.9/27.0
o7.7'97.9 28.1
28.7/28.9
29.7/29.9
30.7/80.9
31.832.0
82.8/83.0
33 .8/34.0
34.8/85.0
358/36 .0;
36.9/37.1
37.9/38 .2
88.9139 .2

89.9/40.2

30.1:
31.1

36,2
87.8

40.4

40.9/41.2

41.4!

laa
]
|
|
|

|
|

19.1
20.1
21.1
22.1
23.1
24.1
25.1
26.1

29.1 29.3

30.3
31.3

82.2 32.4
83.2 83.4
84.2 34.4
35.2.85.4

36.4
37.5

38.4 38.6
39.4 39.7

40.7
41.7

19.3
20.3
21.3
22.3
23.3
24.8
25.3
26.3
27.4
28.5
29.5
80.5
31.5
32.6
33.6
34.6
85.6
36.6
37.7
38.8
39.9
41.0

42.0

19.5.19.7

20.5 20.7

21.5 21.7

22.5 22.7

23.5.23.7

24.5 24.7

25.5 25.7

26.5

26.7

27.6 27.8

llc

29.7
30.7

31.7,

32.8
33.9
34.9
85.9
36.9
38.0
39.1
40.2
41.3

42.3

29.9
30.9
31.9
383.0
34.1
35.2
86.2
87.2
38.3
39.4
40.5
41.6

42.6

19.9
20.9
21.9
22.9
23.9
24.9
25.9
26.9
28.0
29.1
30.1
31.1
32.1
33.2
34.8
35.4
36.4
87.4
38.5
39.6
40.7
41.8

42.9

20.1
21.1
22.1
23.1
24.1
25.1
26.1
27.1
28.2
29.3
30.3
31.3
32.3
33.4
84.5
35.6
36.7
37.7
38.8
39.9
41.0
42.1

43.2

83

Good market milk should have a specific gravity ranging from
1,029 to 1.083 (29 to 33°). A specific gravity differing from this
may indicate either skimming or watering, and in such cases the
dairy milk supply should be investigated.

The simple determination of the specific gravity above is, how-
ever, not decisive. Milk consists of substances which are dissolved
in water, and which increase its specific weight, and suspended fat,
which decreases its specific weight. A skimmed milk will, there-
fore, be heavier, and when adulterated with water, may have the
same specific gravity as a milk which is rich incream. To decide
in such cases, it becomes, therefore, necessary to make an additional
determination of the quantity of fat present.

B.— Examination of skimmed milk: The milk under in-
vestigation is brought into a wide vessel (tea cup shape), and
allowed to remain in a cool place (to prevent souring) for 24
hours. The cream which has collected on the surface, is then care-
fully removed, and the specific gravity of the remainder deter-
mined. For temperature corrections the second table (for skimmed
milk) should be employed.

Unadulterated skimmed milk should have a specific gravity
ranging from 1.032 to 1.036 (82 to 36°); specific gravities under
1.082 indicate adulteration with water.

On the basis of this observation Quevenne has given the follow-
ing table:

A, Whole milk. B. Skimmed milk, Water added,

1.029 — 1.026 (29°-26°) 1.032 (82°) 10%
Lactodensimeter Lactodensimeter

1.026 — 1.028 1.029 20%

1.023 — 1.020 1.026 30%

1.020 -— 1.017 1.0236 40%

1.017 - 1.014 1.0195 50%

Schroeder and Dietzel found that the specific gravity of the
serum of coagulated milk may likewise be used as an indicator for
the adulteration with water. A specific gravity less than 1.026
indicates adulteration with water. Further investigations regard-
ing this point are greatly to be desired.

The fact that milk, after such investigations as have been
described, does not appear normal, may indicate adulteration, but

84

this may also be caused by physiological and pathological pro- —
cesses. If, therefore, an exact chemical and physical analysis
shows deviation from a normal composition, a milk-dealer ¢an,.
simply, on this fact, not be pronounsed guilty of adulteration,
unless his dairy supply has been shown to be of a normal compo-
sition.

The so-called “stable test” is applied only when sufficient
cause for suspicion is given. It consists in a comparison of the
properties of the milk produced by the cows, with those of the
one which has been sold. The cows, to this end, are milked in
the presence of the inspector and witnesses, if possible on the
on the same day, or latest, the day after the suspected milk has
been found in the market. As it is rarely required to get a
thorough knowledge of its composition, the examination is gen-
erally confined to the following parts:

1. Determinations of specific gravity of the whole milk by Que-
venne’s lactodensimeter, reduced to the normal temperature, 15° C.

2. The same, of milk which has been skimmed, after 24 hours’
standing.

3. Determination of the fat by means of the lactobutyrometer
(not creamometer).

The milking of the cows must be done at the usual hour,
and care must be taken that the udders are well emptied. The
milk of all the cows thus milked is then mixed. Yetaside of this,
and when the time allows, the milk of each cow may be examined
separately. It is well to use for the milking of the cows, a disin-
terested person, to he sure that the udder has been completely
emptied. Since, however, it frequently happens that cows milked
by strangers yield less milk, it is as well to let the stable attendants
milk first and to let the other merely ascertain whether they have
done their duty, and if not, to let him complete the milking.
The milk which is at first drawn is always more watery than the
one drawn last. There is even a difference in the quality of the
milk drawn from the different teats. For this reason, and also to
insure complete emptying of the udder, the milking is done cross-
ways, milking two teats in diagonal position at a time. Thus the
complete emptying of the udder can be best effected.

After all the milk thus obtained has been well mixed, the tests
described above are applied. About one pint is taken for subse-

85

quent chemical examination in the laboratory, which includes, in
the first place, an accurate determination of the fat, and determina-
tion of the specific gravity of the milk after skimming. Differ-
ences in the properties of the milk for sale and the milk thus obtain-
ed, indicate the use of adulterants, and the rest of the sample should
then be given to a chemist for further examination, to insure a
good case when it should be brought before the courts. Water,
solids and fat should be determined.

The taking of samples, and the examination in the stable, should
be done in the presence of witnesses.

, Estimation of the quality of the milk by the specific
gravity: The determination of the specific gravity of the whole
and skimmed milk, establishes the degree of adulteration by water.

The percentage of fat establishes the fact whether we have a
normal] or abnormal milk before us.

The percentage of water added may be inferred by the use of
the table previously given (p. 83). Whole milk should have a
specific gravity ranging from 1.029 to 1.033. If the specific grav-
ity be less than 1.029, the milk must be considered adulterated if
a sample taken from the stable should show a different (higher)
gravity. If the specific gravity should be found higher than 1.033,
it may indicate the partial removal of the cream.

If the milk, skimmed after 24 hours’ standing, shows a specific
gravity of less than 1.032, while unskimmed its specific gravity
appears normal, we cenalnile that the milk under examination had
been skimmed and watered.

The quantity of cream removed is inferred from a

Determination of the Fat.

It is to be regretted that as yet for the estimation of fat in
milk, Chevalier’s creamometer is frequently used. When using
this apparatus, the milk is allowed to stand for 24 hours, after
which the amount of cream which has risen to the surface, is de-
termined. The results obtained from this instrument are very
uncertain, and should never be used in proceedings before a court
of justice, for the following reasons:

1. The cream, even under the same conditions, does not rise
evenly.

86

2. Addition of water to milk makes milk appear richer, for the
greater consistency of pure milk prevents the easy formation of
cream.

3. The cream rises quicker or slower according to the tempera-
ture at which the milk is kept. Moreover, the layer of cream
appears larger at lower, and smaller at higher temperatures.

4. Milk frequently sours, and therefore coagulates before the
cream has all risen.

5. The manner of transporting the milk influences the process
of creaming considerably.

6. The cream constantly varies in percentage of fat. Often itis
very rich, then again thinner; sometimes it collects and rises
easily, and at other times less completely.

For comparative quantitative fat determinations, it is advisable
to use, in the place of the costly creamometer, the simpler and
cheaper apparatus of Schatzmann (to be obtained through the
“ Schweizer Molkerei Versuchsstation, at Lausanne’’).

The points mentioned above do not influence the results, which
may be obtained by means of the improved lactobutyrometric test,
whereby the percentage of fat can be determined in milk in from
one-half to one hour’s time, sufficiently exact, while with Chevalier’s
creamometer, we are obliged to wait 24 hours before the very
unexact results can be obtained.

The results obtainable by the lactobutyrometer are not so exact
as those which are obtained by a careful chemical analysis, but suf-
ficiently accurate for the purpose, differing from the truth in the
average not more than 0.2 to 0.3 per cent. Small errors do not,
however, influence the usefulness of the test, if we consider the
value arising from a quick determination of the fat.

The following apparatus are required for the application of
this test :

1. Glass rods for stirring the milk.

2. A water bath to prepare water of 40°C., consisting of a high
cylinder of metal, which rests on a dish upon which alcohol may be
poured and ignited, to heat the water to the required temperature.

3. A glass or metallic cylinder for the water of 20° C.

4. A Centigrade thermometer.

5. A drop glass for potash solution.

6. 3 bottles, one containing ordinary alcohol for burning, another
alcohol of 90 to 92° Tr., and the third ether.

87

7. An alcohometer (Tralles) for testing the alcohol.

8. A tested lactobutyrometer with stopper.

9. Pipettes for alcohol of 90 to 92° Tralles, and ether, discharg-
ing 10 cc. or 5 ¢.c. when blown out.

10. Pipettes for milk adjusted to give 10 ¢.c. or 5 c.c. between
two marks or divisions.

The whole lactobutyrometric apparatus is generally for sale
put up inacase. (See below “ Utensils.”)

The principle of the lactobutyrometer is based upon the obser-
vation, that alcohol separates from milk which has been mixed
with ether, an etheric fat solution, the volume of which stands in
an intimate relation to the quantity of fat dissolved in the ether.
The method and apparatus were invented by Marchand, and the
latter was called by him the lactobutyrometer.

The lactobutyrometer is a tube of equal width throughout
(10 to 12 m.m.), closed at one end. From this point on the lacto-
butyrometer is divided into three equal parts, each being 10 c.c.
or 5¢.c. A space equal to about 1 of these parts must remain to
allow the contents to be well mixed by shaking. The space be-
tween the two upper marks is subdivided into Yo ¢.c.

While the lactobutyrometer may be used by the inspectors, its
results should always be verified by actual analysis, when a case
as to be brought before the courts.

Lactobutyrometer.

88

Determination of Fat by the Lactobutyrometer.

1. The milk must be thoroughly mixed, by shaking the bottle,
or otherwise by agitation with a glass rod, immediately before it
is sampled. If it should be sour, it must be neutralized or made
slightly alkaline with potash solution. The pipette marked milk
is then filled with the milk above the mark, by suction; it is then
quickly removed from the mouth, and the upper opening closed by
the slightly moistened forefinger. By slightiy decreasing the
pressure, the milk may be made to flow out at the bottom. As
soon as the surface of the milk becomes even with the upper mark,
the pressure of the finger is again increased, and thereby the out-
flow stopped. The under end of the pipette is then brought into
the mouth of the lactobutyrometer, and the milk allowed to flow
out until its surface becomes even with the under mark.

If an ordinary pipette is used with only one mark, the last
drop is removed by blowing it out.

2. The pipette marked ether is then filled in a similar manner
as described above, with pure ether, and its contents are allowed
to flow on the milk in the lactobutyrometer, care being taken that
the last drop is brought into the apparatus by blowing it out.

The tube is then closed with a well-fitting cork, and the whole
shaken, lifting the cork from time to time, until milk and ether
form a uniform liquid. This takes several minutes.

During this time the water of 40° C. may be prepared. The
cylinder containing the water is placed upon a dish upon which
some alcohol is poured and ignited. The alcohol is allowed to
burn until the water has reached a temperature of from 40 to
42° C., which is observed by a thermometer suspended in the
water. The alcohol is then quickly extinguished.

3. While yet the water is heating, and after the uniform mix-
ture of ether and milk has been obtained, the third pipette is filled
with alcohol, and the alcohol added to this mixture. The shaking
of the tube is then continued, opening the cork from time to time,
until all lumps have disappeared, and the precipitate, which has
been formed, appears finely flocculent. The lactobutyrometer is
then put into the cylinder, filled with water of 40°C. After-10
minutes standing, the fat solution has well separated from the rest,

89

and appears in that part of the tube which is divided into tenths
of cubic ventimeters.

With the aid of cold water and the water 40° C. warm, water
of 20° C. is then prepared, and the lactobutyrometer is inserted
into this. There it remains for from one-quarter to one-half hour.
The layer of fat is thereby generally yet increased.

Over the solution containing the undissolved albuminates, an
etheric fat solution of high refractive power has accumulated, the
volume of which is read by means of the divisions on the tube.

To this end, the reading is taken from the lower meniscus at the
surface down to the even plane where the lower and upper liquid
meet.

The amount of fat corresponding to the tenths of cubic centi-
meters of solution read, is found in the following tables.

The upper portion of the lactobutyrometer contains 5 ¢.c. sub-
divided into tenths, therefore, 50 degrees. Provided the nade
at the upper end (lower meniscus) had given 45° = 4.5 ¢.¢., and
the lower end of the fat solution, 31° —3.1¢.¢., the height of the
solution would be equal to 14° —1.4 cc.

According to the tables we find the amount of fat = 3. 91
per cent.

Remark; The cleaning of the milk pipette and the lactobutyro-
meter is easiest effected in the following manner: Rinse first with
concentrated soda solution; then with water, strong alcohol, and
ether, successively.

Though this determination of the percentage of fat in milk
requires more manipulation and time than Feser’s lactoscopic
method, it must be considered that this latter instrument is ex-
pected to give only satisfactory results, when it is in the hands of
men well acquainted with analytical chemistry and the handling of
the apparatus. As an easy test to be used by milk inspectors, the
lactobutyrometer is, therefore, to be preferred.

It requires neither special knowledge nor expertness in its use,
and-is, therefore, always to be recommended when it is required to
make practically accurate determination in the shortest possible
time. The place of an accurate determination of the fat by chem-
ical analysis it can, however, not take; but it will always find its
place of usefulness when physicians, inspectors, or dairymen desire
to make a fat determination, in case that the lactodensimeter test is
insufficient to decide the question of adulteration with certainty.

90

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91

Prof. Soxhlet has lately changed the test, in so far as he re-
quires a determination of the specific gravity of the etheric fat
solution.

For practical purposes Soxhlet’s method is too complicated and
costly, on account of the price of the apparatus and the large quan-
tities of ether required. For laboratories it is much to be recom-
mended.

Marchand’s improved method gives also satisfactory results,
and would, for practical purposes, have to be preferred to Soxhlet’s,
since the apparatus is less complicated and costly.

Rules regarding the Execution of the Lactobutyrometric Test.

1. Milk, ether, and alcohol must be exactly measured in pipettes,
each of which is to be used for one of the fluids only. The fluids
must be brought into the lactobutyrometer directly from the pi-
pettes.

2. The lactobutyrometer should be well gauged, as in the case
of these instruments like inaccuracies are liable to occur as in the
lactodensimeters.

3, A large number of experiments have proved that the strength

«of the alcohol need not be absolutely of a certain standard. Some
propose alcohol of 90° Tr., others 91 and 92° Tr. It ‘is certain
that an alcohol of from 90 to 92° Tr. gives the best results, and,
while the use of an alcohol of less strength is indicated for richer
milks, one of greater strength would be required for the examina-
tion of a more watery article.

4, The ether should be very pure 65° — 0.725 specific gravity.

5. The alkali solution should be 36° B., and not more than one
drop of it should be used for each 10¢.c. milk. It should never be
added to the alcohol and ether mixture, but to the milk before any
of these reagents have been added.

Using these precautions in the examination of a whole milk, the
results will always be found to be almost accurate. In examining
a milk which has been skimmed, the difference is easily perceptible.
A milk, which by the use of the lactobutyrometric test, contains
less than 3 per cent. of fat in each of two determinations, should
be examined in the laboratory by exact analysis.

Skimming and addition of water become evident from the
decrease in fat and increase of water. It is referred here to the

92

table previously given on skimmed milk and its percentage of
fat. The inspector’s report is to be verified by an exact determi-
nation of fat and solids.

Mixing of whole and skimmed milk may be inferred by the
data given above.

Foreign substances in milk: The substances most generally
applied have been given on pages 41-43. Also the methods used
for their detection.

Properties of Normal Cows’ Milk and
Market Milk.

Normal cows’ milk and milk of commerce must possess an
agreeable normal odor and taste—z. ¢., it should not emit a dis-
agreeable odor or possess an alkaline or sour taste. The whole and
normal milk of commerce, obtained by mixing the milk of a num-
ber of cows, has an average composition as follows:

Water and volatile substances....... 87.5 per cent.
A Bis cnc eoutemnaneueny cama s ea mais 0.5 «
1) a ee ee eee ne ere 3.5 “
Albuminatey ox0.0.ces ase neravaes 4.0 «
MINK, SUPA. coon cas ware gaalatercnen 4.5 “

Its average spevific gravity, according to many thousands of ex-
periments, ranges from 1.029 (29°) to 1.033 (33°). It contains in
the minimum 38 per cent. of fat and 12.5 per cent. total solids.

For good and normal cows’ milk, these points constitute an in-
disputable truth. Each milk which does not come up to this
standard is a poor article. s

11 per cent. of solids, 2 to 14 per cent. of fat, and a specific
gravity of from 1.031 to 1.035, indicates that such milk has suffered
the loss of one-half its cream.

9$ to 9 per cent. solids, 1 to 4 per cent. fat, and a specific
gravity of from 1.0325 to 1.036, indicates that the milk is skimmed
entirely of its cream.

The Aim of Governmental Control of the
Quality of the Milk Supply.

The inspection of the milk brought upon the market aims not
only at the detection of the adulterations, but must be instituted
to guarantee to the public that the article which they receive is of

93

undoubtedly good quality. That the measures used for its dispen-
sation are correct, should likewise fall within the scope of the
examination. Aside of real adulterations, many other changes
oceur which are of importance, and which are caused either by
sickness, inadequate food and treatment of the animals, but also
by the careless handling of the milk.

For the detection of the first-mentioned causes, the health an-
thorities should confer with a veterinarian.

The question arises here whether producers of an inferior arti-
cle should not be prevented from selling their milk, and should in-
stead be held to find another application for such milk.

The interest of the public undoubtedly demands that we insist
upon such restriction, especially since our advanced knowledge
enables the farmer to remedy, by rational treatment, any abnormal-
ities thus discovered. If, therefore, any man has made it his business,
for the sake of its profitability, to supply milk, he should also be
held to bestow all necessary care upon the production of a good
article, in the same way as it is exacted from the producers of other
food.

One of the best safeguards would be, if the dealers were strict-
ly held to sell their milk for what it is, whole milk, half skimmed,
and wholly skimmed milk, with gradation of prices accordingly,
and that not, as is generally done, they exact the same price, irre-
spective of quality. The sale of a milk at a higher price than
would correspond to its grade, should be considered a fraud. Ordt-
nances to this effect would prevent much wrong-doing, many prose-
cutions, and also much unnecessary expense of time and money for
the entertainment of a large force of milk inspectors.

Prof. Dr. I. Feser, of Munich, an authority in this branch, says:
“The farmer is compelled to remedy existing evils if he is com-
“yelled to bring a normal article to market. But I desire to call
“attention to the fact, that it is equally desirable to prevent the
“sale of milk which is below a certain standard as good milk, even
“if it be simply the unadulterated product of single animals re-
“duced through insufficient and faulty feeding. The inspection
“is, therefure, not only instituted to prevent adulteration, but like-
“wise for the exclusion of an article of inferior value. Ordinances
“passed for the prevention of adulteration would be powerless, if
“it be lawful that milk may be adulterated before its production,
“in the body of the animal, by injudicious treatment and feeding.”

94

R. Schatzmann, in Lausanne, says: “It is not clear, why, at the
“present day, the sale of skimmed milk should in many places be
“interdicted. Everybody knows that cream and butter are sold
“by the same parties who profess that they send so-called good
“milk to market. Thus restrained, many producers are led to
“commit a fraud, as they may not be able to utilize the skimmed
“milk in their own household or for the manufacture of cheese.
“ And why should the public be prevented from buying a yet ex-
“cellent food, if it can be had at a lower price? The producers
“will then not be compelled to commit a fraud, nor will the con-
“sumer be defrauded, when he pays for skimmed milk as such.”

Mitk-dealers should, therefore, be held to sell their goods for
what they are, and at prices ranging uccording to their quality.

For larger cities, ordinances to this effect would be of consider-
able value, especially as it is, in such cases, frequently impossible
to examine the milk at its source. Each dealer in food must know
the quality of the article he sells, and if defrauded himself, he is
not less liable if he defrauds others.

General Rules for a Rational Milk Inspection.

A.--IN CITIES.

1. The inspection includes the milk as furnished by the
producers as well as the dealers.

2. At the inspection at the place of sale, the following points
should be observed :

a. Cleanliness in the handling of the milk and the vessels in
which it is carried. For transportation as well as storage the use of
only such vessels should be permitted, which allow an easy and
thorough cleaning. They should have, therefore, sufficiently wide
openings. They should neither be made of copper nor zine, and
should not be kept in places which are used as dwelling rooms, or
in such places where garbage or other bad smelling substances are
near.

b. The correctness of the measure for retail sales should be
verified.

c. Note should be taken of the quantity of the milk brought
to market, and the number of cows which have contributed to this

95

supply, since it frequently happens that the figures thus obtained
are quite out of proportion.

d, Examine appearance, odor, taste, and reaction. A strongly
alkaline or acid milk, or one with bad taste, should be confiscated.
The use of preservatives should be considered an adulteration.

é. Determination of temperature to ascertain whether heat has
been applied to preserve the milk. A temperature of over 35° C.
would indicate that such has been done.

J. Statements as to quantity and price of the milk.

g. Each sample taken is given a number, and on the record
book the following facts must be stated :

Name of seller.

Occupation of same (producer or dealer).

Age of same, and residence.

If the seller be merely dealer, he must state name of producer,
and number of cows kept by the same.

A. The sampling of suspicious milk is done after it has been
well mixed by a dry and clean rod. One-half liter is then bot-
tled, sealed, and labeled in the presence of witnesses. The label
on the bottle gives merely the number under which the sample
has been entered in the inspector’s book, to avoid that the chemist
may be charged with partiality. The samples should be paid for,
and, on demand, a similar sample, sealed and labeled, should be
prepared for the dealer, that he may have an analysis made at his
own expense.

3. At the laboratory the following tests are made:

If a sample is to be forwarded to an expert at some distance, it is
well to insert the bottle containing it into boiling water for one-
half or one hour. It is then sealed and labeled. Milk thus treated
will bear transportation easily without souring.

a. Determination of the reaction of the milk with litmus or
turmeric paper.

b. Boiling of the milk when strongly acid.

c. Determination of the specific gravity by means of an ac-
curate Quevenne’s lactodensimeter, on the fresh milk, and on the
milk skimmed after 24 hours standing.

d. Determination of the fat by means of an accurate improved
Marchand’s lactobutyrometer, or by some other sufficienily accurate
method (the creamometer cannot be counted amongst these).

96

e. Determination of solids by approved chemical method.

The accuracy of the apparatus is of the greatest importance,
and the utmost pains should be taken to insure it. It would be
well, if from the part of the government, steps be taken to insure
that only accurate instruments be brought into the market, by ap-
pointing a person, whose duty it shall be to test and mark all such
instruments which have stood the test. That the iustruments,
which are sold without this precaution, are almost without excep-
tion incorrect, is a notorious fact.

The work of verifying the correctness is by no means an easy
task, and should be given into proper hands.

B.--IN THE STABLE.

The stable test, which can be easily made in smaller cities and
villages, is frequently not applicable in larger cities, owing to the
distances from which the milk is brought. In such cases an ordi-
nance binding the dealer to sell the milk only nnder such names as
indicate its real character, should be substituted.

Wherever the stable test can be made, and is in use, the fol-
lowing rules should be observed.

a. The milking is to be done, if possible, at tne usual time and
with the assistance of a disinterested person.

b. The specific gravity is determined by means of the lactoden-
simeter, at a temperature as near as possible to 15° C.

e. The reaction of the milk is taken.

ad. Samples of about 1 pint are taken for the determination of
the fat and specific gravity of the milk skimmed after 24 hours
standing.

e. The number of cows, their age, period of lactation, health
and feed, ete., are to be noted.

jf. The book stating the sales during two weeks past, is to be
examined, and thus the quantity ascertained compared with the
quantity of milk obtained at the time of examination.

g. General information from attendants as.to the feeding of
the cows, handling of milk vessels and milk, and quantities of milk
used for obtaining cream, is also to be obtained.

The correctness of the notes taken is to be verified by the sig-
nature of a witness.

97

Proposition Stating the Main Points for an
Ordinance Regulating the Sale of
Milk in Large Cities.

For the protection of the public against fraud and injury to
health, the following points suggest themselves.

1, All dealers in milk should be licensed, and licenses be grant-
ed only to responsible parties. The sale of milk by unlicensed
parties is prohibited.

2. A record should be kept of the names, residences and places
of business of all licensed dealers.

3. Dealers should be acquainted with the use of the lactoden-
simeter, lactobutyrometer and litmus paper.

The government should aid this education by free lessons and
printed statements explaining the use of these instruments.

4, Only fresh milk should be brought to market, and it should
not be sold under the general denomination of “milk,” but from
vessels marked clearly and in large letters, at a part easily seen,
stating their contents as:

Whole milk.

Milk half creamed.

Skimmed milk.

5. Excluded from sale be all milk from cows sick with pulmo-
nary fever, anthrax, tuberculosis, and aphtha epizootica (hoof and
mouth disease), likewise, bitter, salty, mucous, abnormally col-
ored, spoiled or adulterated milk.

6. The greatest cleanliness shall’ be observed regarding the
vessels and measures for the milk, as well as the stores, which
must be airy, dry and cool, and which should in no wise be used
whereby the purity of the milk be endangered. It should never
be kept in places used for sleeping rooms.

7. Inspectors are entitled to take samples from all stores or
other places where milk is sold, against receipt or payment.

&. The inspection must always be done in the presence of at
least one witness, who must countersign the record.

98

Propositions for Regulations Governing
Producers of Milk and Milk-Dealers.

The farmer should know what he brings to market. M.
Fleischmann says with reference to this :

“The farmer, whose intention it is to better himself by bring-
“ing his husbandry upon a rational basis, must know the value of
“his cows. To this end he requires aids which allow him, without
“being a scientist himself, to ascertain whether the milk of cer-
“tain cows be watery or rich in solids, and what the yield of
“cream is in special cases. He is more interested in comparing
“one milk with another, than in knowing the actual difference by
“percentage.”

Considering this, it cannot be considered as asking too much if
it be required that farmers and dairymen should be held to regula-
tions as follows :

a. Strict supervision over the cattle, stables and feed.

6. Occasional examination of the milk of single cows, and the
yield of all mixed, with the aid of the lactodensimeter, Schatzmann’s
cream test or lactobutyrometer.

e. Abnormal or spoiled milk shall not be sold.
d. Regularity in the time of milking must be observed.

e. The milk is to be properly cooled by putting the vessels
containing it in cold water, and stirring it slowly until it has
reached the temperature of the water.

jf. The cooled milk must be kept in a cool place.

g. The farmer shall keep notes respecting number of cows and
daily yield of morning and evening milk.

h. No milk drawn before the eighth day after calving shall be
brought to market. Likewise none from sick animals, or such
under medical treatment, or of cows which have to be watered
with unhealthy stagnant water.

i. The greatest cleanliness must be practiced during milking,
storing, or transporting the milk.

99

Considering the consequences wrought by adulterated or other-
wise unhealthy milk, upon the health of consumers, it is certainly
not asking too much if, in the interests of humanity, exemplary
punishment for this crime is demanded, and that, especially, the
highest punishments which are possible under the law, be dealt
out to such persons, which have been held before for the same
offence. .

100

LIST OF APPARATUS AND CHEMICALS
REQUIRED FOR THE ANALYSIS OF
MILK AND INFANTS’ MILK-FOODS.

Blue and red litmus paper, turmeric paper, distilled water,
absolute alcohol and ether. _

Chemically pure hydrochloric, nitric, sulphuric and acetic
acids.

Sulphuric acid of commerce (66° B), and calcium fluoride in
powder, for cleaning platinum vessels.

Dilute sodium or potassium hydrate solution of known
strength, to neutralize the hydrochloric acid used for inversion.

Potassium hydrate solution of 1.048 specific gravity (50 potas-
sium hydrate and 1000 water), to neutralize Ritthansens’ cupric sul-
phate solution.

Cupric sulphate solution (63.5 grms. crystallized cupric sulphate
dissolved to 1 liter).

Fehling’s solution (see page 28).

Uranium solution according to Neubauer, see Fresenius’ Quan-
titative Analysis.

Iodine solution (1 iodine to 50 water).

Phenolphtalein as indicator in volumetric analysis. Dissolve
1 part in 30 parts of alcohol, and use from 1 to 2 drops at a time.

Potassium ferrocyanide solution as a test for copper, in Feh-
ling’s volumetric sugar determination.

Glazed paper.

Swedish filter paper, free from ashes, is obtained according
to P. T. Austen, by soaking for from 4 to 5 days the filters,
which had previously been washed with diluted hydrochloric acid,
ina mixture of 30 ¢.c. concentrated hydrochloric acid, 15 ¢.c. com-
mercial hydrofluoric acid, and 500 ¢.c. distilled water. The fluid
is then poured off, and the filters are washed with warm water
until no muriatic acid reaction is obtained. They are then dried.
The following manufacturers prepare paper free from ashes:
Schleicher & Schuell, Darren, Prussia; Linke and Rosala, Bruenn.

A fine chemical balance and weights.

Microscope, magnifying power to 400 or 500 linear dimension.

Thermometer (Celsius).

Specific gravity bottle with thermometer Geissler, in Bonn,
Prussia.

101

Platinum dishes and crucibles with covers and spatules.
Porcelain crucibles with cover; for the incineration of the

albuminate copper precipitate.

Glass cylinders with foot, of from 250 to 1000 c.c. contents.

Liter and 1-2 liter flasks.

Several nests of beaker glasses.

Several nests of porcelain dishes.

Glass flasks of from 50 to 500 cc. contents.

Pipettes of from 5 to 50 ce. contents divided into vr ¢.c.

Burettes, 50 ¢.c. contents, divided into 7s ¢.c., with pinch cocks
or glass cocks, together with supports of wood or iron.

Wash-bottles for distilled water, alcohol and ether.

Large watch glasses, well fitting, and clamps to hold them.
They serve to hold the filters which are to be weighed.

Larger and smaller dessicators, with chloride of calcium or sul-
phuric acid.

Forceps of wood and of brass, platinum pointed.

Glass rods of various sizes and thickness.

Glass covers.

Feather brushes (black and stiff).

Rubber covered rods for removing precipitates.

Platinum or clay pipe stem triangles.

Ring stands.

Muffie.

Water baths, with rings and covers.

Air bath, with thermometer and temperature regulator.

Water aspirator.

* Liebig’s coolers and stand.

Areometer, according to Tralles.

Lactodensimeter, with thermometers and glass cylinders. Manu-
factured by. Alt, Eberhard and Jaeger, Ilmenau, Germany, or
Greiner and Friedrichs, Stuetzerbach.

Lactobutyrometer, same manufacturers.

Schatzmann’s cream tester, R. Schatzmann, Milch Versuchs-
station, Lausanne.

Gerber’s apparatus for the determination of the fat, Greiner
and Friedrichs, Stuetzerbach, also Alt, Eberhardt and Jaeger, Il-
menau, Germany; Fréres Alvergniat, rue de la Sorbonne, Paris.

Gerber’s set of apparatus for home use and milk inspection, in
case, as well as all other instruments used for milk testing, may be
obtained from the author. Correctness guaranteed.

LEHN & FINK,
Wholesale Druggists,
IMPORTERS AND EXPORTERS,
No. 160 William Street,

NEW YORK.

We call the attention of the Profession to our
large and complete stock of strictly pure

CHEMICALS,
ACIDS,
METALS,
MINERALS,
ALCALOIDS, ete., etc.,

constantly imported direct from the most reliable
sources in Europe, in suitable original packages
to meet the wants of Laboratories, Manufacturers,
Colleges and Chemists in general.

RARE AND NEW ARTICLES A SPECIALTY.

Collections of Minerals, Alcaloids and Physio-
logical Preparations on hand and imported to
order.

Quantity Supplies for Institutions, Schools, etc.,
imported to order at special rates.

All orders will be executed with utmost care
and promptness at lowest market prices.

LEHN & FINK,

P.O. Box 3114, N.Y.

Established 1850.

J.& H. BERGE,

Importers, Manufacturers and Dealers in

CHEMICAL AND PHYSICAL APPARATUS

—FOR—

CHEMISTS, ASSAYERS, COLLEGES, LABORATORIES, Ete.

Best Bohemian Glassware,
BEST GERMAN PORCELAIN AND GLASSWARE,
Crucibles of every description.
Pure CuHemicaLts anD REAGENTS,

PLATINUM WIRE, FOIL, DISHES, CRUCIBLES, ETC

Improved Bunsen Burners, all styles,
Improved Bunsen Blast Lamps & Combustion Furnaces.

FurnaAcES, BLowripres of all kinds; Lamps, all kinds;
QUEVENNE’S LACTODENSIMETERS, LACTOBUTYRO-
METERS, and all other apparatus required
for the examination of Milk,

etc., etc., etc.

95 John Street, and 191 Greenwich Street,
P. O. Box 401. NEW YORK,

Apparatus of all kinds made to order and repaired in a superior
manner at moderate prices.

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