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THE BOOK OF MIE DAIRY

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THE BOOK OF THE DAIRY

A MANUAL OF THE
SCIENCE AND PRACTICE OF DAIRY WORK

TRANSLATED FROM THE GERMAN OF

W. FLEISCHMANN, Ph.D.

PROFESSOR OF AGRICULTrRE AND DIRECTOR OF THE AGRICULTURAL INSTITUTE,

KONIGSBERG UNIVERSITr, PRUSSIA

HONORARY MEMBER OF THE ROYAL AGRICULTURAL SOCIETY OF ENGLAND

BY
C. M. AIRMAN, M.A., Sc.D., F.E.S.E., F.I.C.

FORMERLY LECTURER ON AGRICULTURAL CHEMISTRY, GLAStiOW TECHNICAL COLLEGE, AND
EXAMINER IN CHEMISTRY, GLASGOW UNUVERSITV

R. PATRICK WRIGHT, F.H.A.S, F.RS.E.

PROFESSOR OF AGRICULTURE
GLASGOW AND WEST OF SCOTLAND TECHNICAL COLLEGE

LONDON

BLACKIE & SON, Limited, 50 OLD BAILEY, E.C.
GLASGOW AND DUBLIN

Digitized by the Internet Archive

in 2010 with funding from

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PREFACE.

The English editors have prepared this edition of Professor
Fleischmann's comprehensive treatise on Dairying in the
belief that in doing so they are placing in the hands of
British dairy-farmers a work on the science and practice of
their difficult art which will be found invaluable alike for
study and for reference. They also believe that it forms
a text-book specially well fitted to supplement and explain
to students at our numerous Dairy Schools and Agricultural
Colleges the practices of dairy management there shown in
operation.

Professor Fleischmann has long enjoyed the reputation of
being one of the greatest living authorities on the science
and practice of dairying, and his treatise in German is
familiar to all specialists as the best work on the subject.
The great advances made in agricultural education in this
country in recent years have been the means of calling into
existence a number of excellent works in the different depart-
ments of agricultural science; but the editors believe that
Professor Fleischmann's work, in an English form, supplies,
in the conventional phrase, " a felt want". They trust that
the addition of a considerable number of illustrations (not
included in the German edition) will still further enhance its
value.

The great importance of milk and other dairy products
as articles of diet renders any work dealing with the subject
of great interest to many others besides the dairy-farmer and

VI PREFACE.

the agricultural student. It is anticipated by the translators
that the work will be found of value by medical men gener-
ally, and more especially by officers of public health. They
also hope that it may afford some assistance to agricultural
and analytical chemists, as well as to other sanitary authorities
charged with the administration of the Adulteration of Foods
and Drugs Act.

The monetary value of the interest involved in dairy
produce is pointed out at greater length in the Introduction.
It may suffice here merely to refer to the fact, that an annual
income of over £32,000,000 is estimated to be derived in
this country from the sale of dairy produce, or one-sixth of
the whole income of British agriculture. But enormous as
this sum is, it is not all that is paid by the consumer for
dairy produce, since we import it from other countries to the
extent of over £20,000,000 per annum. Much of the produce
represented by the £20,000,000 finds a ready market in
Britain chiefly because of its high and uniform quality.
There is no reason, however, why dairy produce of an equally
uniform and of even a higher quality should not be manu-
factured at home, and thus the best position be retained in
our own markets. In achieving this object everything which
tends to bring about a better and more scientific knowledge
of dairying may be said to help, and it is the confident
expectation of the translators that the present volume will
not be found altogether inefiective in promoting this purpose.

CONTENTS.

CHAPTER I.

THE SECRETION, PROPERTIES, AND COMPOSITION OF MILK.

1-24. — Definition of milk. Structure and nature of cow's udder. Teats. Forma-
tion of milk. Researches on process of milk secretion. Properties of milk
— chief constituents of, effect of heat on, physical nature of, nitrogenous
matter of. Caseous matter. Albuminoids — researches on nature of. Milk-
fat or butter-fat — specific gravity of, state of division of, its chemical com-
position. Milk-sugar — action of heat on, properties of. Inorganic or mineral
constituents — composition of. Other constituents of milk. Percentage com-
position of cows' milk. Specific gravity of milk. Relation between specific
gravity and fat and total solids of milk. Formulae showing relation. Colostrum
or beastings. Its composition. Corps granuleux. Secretion of milk in udder.
Intervals of milking. Lactation periods. Age of cows. Effect of bulling.
Working of milk cows. Feeding. Result of increasing digestible constituents
of food. Relation between feeding and richness in fat of milk. Feeding stan-
dards. Utility of foods. Composition of foods. Suitable foods. Effect of food
on properties of milk. Milk yields. Conditions influencing yield of milk.
Milk-yielding capacity of cows. External appearances indicating high milk-
yielding capacity. IMilk faults — bitter, coloured, ropy, lazy, and sandy milk.
Milk diflScult to churn — goats' milk, sheep's milk, mares' and buffalo milk, pp. 1 -57

CHAPTER II.

THE EXTRACTION, IMMEDIATE SALE, AND TESTING OF MILK.

25-35. — Milking — position of hands in, importance of cleanliness in. Treatment
of milk after milking — cooling of, addition of preservatives to. Pasteurizdng
of milk. LawTence refrigerator. Distribution of milk. Railway milk-cans.
Cart milk-can. Value of milk for fattening purposes. Value of milk as an
article of sale. Profitable methods of disposal. Precautions in sale of. Milk
adulteration. Adulterants. Milk testing — value of chemical analysis in.
Formulse for calculating composition of milk. Soxhlet's aerometric fat method.
Lactocrit-Marchand method. Byre test. Variations in composition of milk.
Supervision of milk trade in towns — tests necessary for. Conditions regulating
sale of milk. Cream. Supervision of milk in large collecting and co-operative
dairies. Selling milk according to its percentage of fat. Milk-ferment and
rennet test. Supervision of the production and manufacture of milk. List of
dairy instructions. Analysis of milk. Determination of water, total soUds, fat,
nitrogenous matter, milk-sugar, and ash. Detection of adulteration, . pp. 58-89

VIU CONTENTS.

CHAPTER III.

MILK IN ITS RELATION TO MICRO-ORGANISMS, DAIRYING,
AND BACTERIOLOGY,

§ 36-46. — Bearing of bacteriological research on dairying. Importance of cleanliness
in dairying. Lower fungi. Different forms of bacteria. Action of bacteria.
Distribution of lower fungi. Forms and life conditions of bacteria. Effect of
temperature on bacteria. Sterilization of milk. Intermittent sterilization.
Contaminated milk. Methods of sterilization. Spontaneous coagulation of
milk and souring of cream. Lactic fermentation. Different kinds of milk
diseases. Premature coagulation of mUk. Slimy or ropy milk. Development
of colours in milk. Bacteria causing colours. Micro-organisms in cheese.
Fission fungi. Organisms necessary for ripening of different cheeses. Organisms
deleterious to cheese. Characteristics of milk owing their origin to micro-
organisms. Kephir. Destruction of micro-organisms. Practical application of
bacteriology, ...» jjp. 89-105

CHAPTER IV.

THE MANUFACTURE OF BUTTER.

§ 47-106.^Different methods in which butter is made. Methods of obtaining cream.
Old method of cream-separation. Cream-raising. Rising of fat globules to
surface of mUk. Conditions necessary for creaming. Different methods of
cream-raising. Temperature for cream -raising. Older methods of cream -raising.
Swartz method. Cold water method. Collection and storage of ice. Unit
of heat. Methods of cream -raising. Cream-yielding coefficient. Centrifugal
force. Value of centrifugal force for cream-raising of milk. Alexandra cream
separator. MUk in the separator drum. Inflow of milk into separator. Outflow
of cream and skim-milk from separator. Regulation of proportional weights of
cream and skim-milk in separation of milk. Size and reliability of separator
drums. Milk-separators at present in use. Lefeldt separator. Separators made
by Separator Co., Stockholm. Laval separators. Laval hand separators. Alpha
separators. Burmeister & Wain's separators. Peterson patent separator. Vic-
toria separators. Balance separators. Separators at present in use in Germany.
Best separators. Cream-raising coefficient in connection with use of separators.
Conditions influencing cream-raising coefficient in separators. Supervision of
revolving rate of drum of separators. Supervision of quantity of milk creamed
per hour. Regidation of temperature in separation of milk. Regulation of
relative quantity of cream and skim -milk in use of separators. Condition of
cream and skim-milk from separators. Lawrence refrigerator. Laval cream-
cooler. Proper working of centrifugal machines in dairies. Forces brought into
action in operation of separators. Hand separators. Separator residue. Cream.
Composition of cream. Skim-milk. Composition of skim-milk. General
remarks on butter-making. Butter chums. Churns. Swinging, cradle, and
rocking chums. Chums vrith horizontal barrels. Churns with vertical barrels.
Chums of uncommon and special construction. Practical value of different
chums. Preparation of milk for churning. Churning. Temperature for
churning. Churning of sour cream. Churning of milk. Experiments made
to obtain butter by uncommon methods. Centrifugal butter separator. Colour-
ing of butter for use. Salting of butter. Working and kneading of butter.
Butter worker. Curd knife. Holstein butter worker. Butter trough. Yield

CONTENTS. IX

of butter. Different kinds of butter. Fresh butter. Preserved butter. Whey
butter. Melted butter. Butter-milk. Composition of butter-milk. Properties
of good butter. Common faults of butter. Chemical composition of butter,
Analysis of butter. Determination of water, fat, ash, proteids, non-nitrogenous
bodies, preservatives, and colouring matters in butter, pp. 106-199

CHAPTER Y.

CHEESE AND CHEESE-MAKING.

§ 107-128. — Coagulation of milk and properties of coagulum. Curd. Coagulum or
raw cheese. Coagulation of milk by acids. Chemical composition of casein,
paracasein, and whey-protein. Rennet and its properties. Strength of action
of rennet. Directions for using rennet. Rennet powder. Rennet substitutes.
Preparation of rennet. Application of rennet in practice. Time for coagulation.
Testing of rennet solution. Colouring of cheese. Utensils necessary in prepara-
tion of cheese. Cheese vat for steam. Cheese vat for hot water. Steam cheese
kettle. Oneida cheese vat. Cheese tub. Treatment of curd before moulding.
Cheese breaker and ladle. Curd stirrer and knife. Shaping of rennet cheeses.
Cheese rooms. Pressing of rennet cheeses. Wooden cheese vat. "Two in one"
double cheese press. "Gleed" press. Swiss lever press. Lever press. Salting
of cheeses. Ripening room for cheeses. Art of cheese-making. Function of
bacteria in ripening. Ripening of cheese — chemical changes effected by, function
of fungoids in. Defects of cheese. Preparing of cheeses for market. Different
kinds of cheese and their classification. Cheeses of a soft and oily character
made from cows' milk. Soft cheeses. Preparation of Neufchatel cheese. Rennet
cheese of a firm character, made from cows' milk. Hai-d cheeses. Preparation
of cheddar cheese in America. Preparation of cheddar cheese in England.
Preparation of Edam cheese in Holland. Preparation of Emmenthal cheese
in Switzerland. Bacillus diatrypeticus casei. Cheese from sheep's milk. Pre-
paration of Roquefort cheese in France. Cheese from goats', buffalo, reindeer,
and mLxed milk. Sour milk cheeses. Curd mill. Cheshire curd mill. Cheese-
like products from refuse of cheese manufactories. Mysost. Schottensicht.
Ziger cheese. Liquid residue of cheese. Its composition. Yield of cheese.
Chemical composition of cheese. Analysis of cheese. Determination of
water, fat, ash, nitrogenous matter, and milk-sugar. Composition of different
cheeses, pp. 200-275

CHAPTER Yl.

PREPARATION OF KEEPING MILK, FERMENTED MILK, AND
THE BYE-PRODUCTS OF MILK.

§ 129 138. — Keeping milk. Pasteurized milk. Laval milk-scalder. Different forms
of Pasteurizing apparatus. Temperature necessarj' for Pasteurization. Steri-
lized unthickened milk. Sterilizing apparatus. Properties of sterilized milk.
Condensed milk. Yacuum pan for condensing milk. Composition of condensed
sweetened milk. American unsweetened condensed milk. Fermented milk.
Ropy milk. Kephir — its properties, its preparation, its composition. Koumiss
— its preparation, its composition. Ropy milk. Milk-sugar — its preparation,
its composition. Bye-products of milk of minor importance. Keschk. Lactarine.
Lactite, pp. 276-295

■X CONTENTS.

CHAPTEE VII.

THE ECONOMIC ASPECTS OF DAIRYING. •

§ 139-146. — Sale of milk for direct consumpt. Utilization of milk by making it into
butter. Utilization of milk by making it into fat cheese. Countries adapted
for making milk into cheese. DiflBculty of marketing cheese. Utilization of
milk in different countries. Calculations for different methods of milk utiliza-
tion. Amounts realized by different milk products. Profit from sale of milk for
direct consumption. Profit from manufacture of fatty soft cheese. Profit from
hard cheese. Profit in ice treatment and manufacture of butter and half -fat
cheese. Keeping of books. Machine for weighing milk. Milk registers. Yields
of various milk products. Payment of milk according to weight and composi-
tion. Payment of milk in dairy companies in which fatty hard cheeses are
made. Payment of milk in dairies having a limited trade. Structure and
arrangement of a large dairy, pp. 296-315

CHAPTEE VIII.

MARGARINE AND MARGARINE CHEESE.

§ 147-8.— Margarine — history of its discovery, extent of trade in, fats used in manu-
facture of. Butterine — fraudulent manufacture of. Development of trade in
different countries. Composition of Margarine. Margarine cheese— limited
demand for, preparation of, .... pp. 316-326

CHAPTEE IX.

§ 149.— EXPLANATION OF TABLES IN APPENDIX, pp. 327-330

LIST OF ILLUSTRATIONS.

PLATES.

PAGE

Ayrshire Cow "Polly II. of Knockdon", - - Frontispiece.

The Cow's Udder — Double Coloured Plate (figs. 1 and 2), - - - xx

Jersey Cow "Chestnut II.", 48

Dexter Cow "Rosejiary", 58

Shorthorn Cow "Molly Millicent", 88

ENGRAVINGS IN THE TEXT.

FIG.

3. Bundle of Elastic Fibres and Connective Tissue Fibres of Cow's Udder, - 1

4. Gland-lobules, .... 2

5. Alveoli, . - - - 2

6. Cylindrical Epithelial Cells, 2

7. Capillaries of Mammary Glands, ........ 2

8. Milk-cistern and Outlet Tube of Milk-gland laid open. (Two-thirds of natu-

ral size). -------------3

9. Plaster of Paris Cast of the Posterior Milk-cistern, with the Canal of the

Teat, of an Ayrshire Cow, ----...-. 4

10. Plaster of Paris Cast of the Posterior Milk-cistern, with the Canal of the

left side of the Udder of a Dutch Cow, --.--.. 4

11. Plaster of Paris Cast of the Milk-cistern and Milk-ducts of the ISIilk-gland

of a Dutch Cow. (Natural size), ........ 5

12. Plaster of Paris Cast of the Canal traversing the Teat and Nipple, - - 6

13. Section of Membrane of Lower and Narrow Portion of the Canal of the Teat, 6

14. Section of Sebaceous Gland, .........7

15. Tallow Follicle of the Nipple, 7

16. Tallow Follicle of Nipple, 7

17. Milk-globules, 19

18. Colostrum Corpuscles, ----------- 36

19. Pyrenean Milking Goat, 54

20. Friesian MUking Sheep, 55

21. Position of Hands in Milking, 59

22. Lawrence Refrigerator, .......... 61

23. Railway Milk-can, 62

24. Top of Milk-can, with Seal and Pincers, showing Mode of Fastening, - - 63

25. Cart Milk-can, 63

26. The Lactocrit, 70

27. Different Forms of Bacteria, 91

28. Sectional Illustration of the Alexandra Cream-separator, .... 121

29. Lefeldt's Separator. (Section), ......... 127

xii LIST OF ILLUSTRATIONS.

FIG. PAGE

30. Amoldt's Hand Separator. (Perpendicular Section through the Drum), - 128

31. Steam-turbine Separator, 129

32. Perpendicular Section of Steam-turbine Separator, 130

33. Two Laval Separators with Milk Warmer, 131

34. Perpendicular Section through the Drum of the Laval Hand Separator, - 131

35. Alpha Separator, Xo. 1, --------- - 132

36. Alpha Hand Separator (K), 134

37. Alpha Baby Hand Separator, 134

38. Alpha Hand Separator (B), 134

39. Danish Centrifugal Cream-separator (Burmeister and Wain). (Perpendicu-

lar Section), 135

40. Hand Separator (Burmeister and Wain), - - - - - • - 136

41. Burmeister and Wain's Hand-power Separator. (Perpendicular Section), - 137

42. Victoria Hand-power Cream-separator, -.-.--- 138

43. Sectional View of Victoria Hand-power Cream-separator. - - - - 139

44. Section of the Balance Separator, 140

45. Lawrence's Refrigerator, ---------- 148

46. Laval Cream-cooler, - - - - - - - - - - -149

47. Cotswing Churn, ----------- 162

48. Box Chum, 162

49. Diaphragm Chum, - - - - -163

50. Victoria Chum, 1G4

51. Centrifugal Butter-separator, ..- 175

52. Butter- worker, - - - - - - 180

53. Butter-knife, 180

54. Butter- worker, - - - - -181

55. Holstein Butter-worker, 181

56. Butter-trough, - - - 182

57. Cheese Vat for Steam, 214

58. Cheese Vat for Hot Water, 214

59. Fixed Cheese Kettle with Movable Firing. (Perpendicular Section), - - 215

60. Fixed Cheese Kettle with Movable Firing, 215

61. Steam Cheese Kettle. (Perpendicular Section), 216

62. Oneida Cheese Vat. (Perpendicular Section), 217

63. Cheese Tub, 218

64. Cheese Ladles, 219

65. Curd Stirrer, 219

66. Curd Breaker, 219

67. Curd Knife, 219

68. Curd Knife with Horizontal Plates, 219

69. Curd Stirrer, 219

70. Wooden Cheese Vat to open -ndth Key, ------- 224

71. "Two in One" Double Cheese Press, 224

72. Gleed Press for Soft Cheeses, - - 225

73. Swiss Lever Cheese Press. 225

74. Lever Press, ...---..---- 226

75. Bacillus Diatrypeticus casei, - - - 260

76. Curd Mill, 266

77. Cheshire Curd Mill, 267

78. Laval Milk Scalder, 277

LIST OF ILLUSTRATIONS. XII

FIG. P^^'^

79. Pa.steurizing Apparatus (Burmeister and Wain), 278

80. Pasteurizing Apparatus (Lefeldt), 2/9

81. Sterilizing Apparatus, 281

82. Vacuum Pan for Condensing Milk, -------- 283

83. Machine for Weighing Milk, - . . - .... 306

84. Machine for Weighing Milk, ...-----• 307

85. Model of Large Dairy, 315

INTRODUCTION

BY THE ENGLISH EDITORS.

It is generally allowed by those who have given attention to the
progress of agriculture during the past thirty years, that perhaps the
most prominent feature in its history has been the gi-eat change
that has taken place in that time, in the methods and processes of
dairying, and in the relative importance assigned among English-
speaking peoples to dairying as a branch of agricultural science and
practice. This is very clearly evidenced in all works on agricultural
science and practice written prior to the present decade, in which
it will generally be found that, while some pages are devoted to
a description of dairy breeds of cattle, very little space is accorded
to the consideration of questions relating to the management and
treatment of milk, and the manufacture of butter and cheese.

The comparative neglect of dairying science, up to the present
time, is probably attributable to two causes. In the first place,
other branches of agriculture contributed in a much larger degree
then than now to the revenue of agriculture; and in the second,
dairying as an art was imperfect and empirical, and as a science had
little or no existence. Up to the time when the import of foreign
wheat to Britain began to assume large dimensions, the income and
profits of our farmers depended in very great measure on the returns
from wheat and other cereal grains. In the year 1869, for example,
the total area under wheat in the United Kingdom was 3,862,202
acres, which was estimated^ to yield 113,331,777 bushels of an
average value of 6.s. Old. per bushel. The total value of wheat
(grain only) to the agriculture of the United Kingdom in 1869 was,
therefore, more than £34,000,000 sterling. As the value of wheat,
however, from that year underwent a steady decline owing to a con-
stant increase in the foreign supply, the cultivation of this cereal
was gradually abandoned by farmers as the returns became unpro-

^ R. F. Crawford, in Journal of the Royal Agricultural Society, 1895.

xvi INTRODUCTION.

fitable, and by the year 1893, the value of wheat in British agricul-
ture had suffered a remarkable diminution. In that year the area
under wheat in the United Kingdom had fallen to 2,215,355 acres.
The yield was estimated at 67,717,160 bushels, and the price was
3s. Shd. per bushel. The total value of the home-grown crop
(grain only) in 1893 was, therefore, a little over £11,000,000 ster-
ling, or less than a third of its value fifteen years previously. A
similar, though less extreme, change had in the meantime taken
place in the prices of barley, oats, and other less extensively grown
grains; and other of the more important sources of farm income had
undergone a similar depreciation in value. Beef, which along with
grain constituted a chief source of income on the greater part of
arable area in Britain, also suffered a serious fall in value in the
same period. This heavy depreciation in values told not less
seriously on the agriculture of Canada and of America than on that
of Britain. Over a very large area, in both of these countries, the
income of the farmer depended primarily on the price of wheat; and
as the price has suffered year by year a steady decline, the position
of the farmer has been constantly changing for the worse. Mean-
time, while all departments of agriculture have suffered more or less
severely from the heavy fall in the value of beef, mutton, and
grain, farmers whose income depended more largely on returns
from dairy produce, remained, up till 1894, in a relatively prosperous
condition. Not only have cheese and butter continued at high prices,
but, with the steady increase of the population of the United King-
dom, as well as of America and of the Colonies, a much-increased
demand has developed for articles of dairy produce, such as milk
and cream, in which there has been no foreign competition of such
a character as to affect prices seriously. Moreover, apart from
increase of population, the practice of using milk as a regular article
of diet has undergone a remarkable development during these years.
This has probably originated in a more extensive knowledge of the
value of milk as a food, and its intrinsic cheapness as compared with
other foods; but it has also been encouraged in great measure by
improvements in the supply, brought about by the development
of railway enterprise, and by the guarantees of good quality which
have been secured in all our large towns by the strict and careful
enforcement of the measures and stringent regulations prescribed
by local authorities for the construction of byres, the arrange-
ment of dairies, and for the control of the milk supply and the

(M175)

INTRODUCTION. XVU

prevention of adulteration. Not a little of the increase in the
consumption of milk has been due to the enterprise of dairymen
and milk-sellers, and to the larger dairy companies in our cities,
who, by attention to cleanliness, by prompt and convenient supply,
and by the employment of the best-known means for the detection
of adulteration, have succeeded in inspiring the public with confi-
dence in the soundness and quality of the dairy produce supplied
by them. Consequently, while other articles of farm produce have
been steadily falling in value, milk has remained in good demand
at a comparatively high level of prices, at prices that were, indeed,
rising during a number of the years when the depression in
arable agriculture, outside of the dairying districts, had reached
its most acute and disastrous stage. The effect of these various
influences, the fall in the value of other articles of agricultural
produce, together with the increased consumption of dairy produce
and the maintenance of high relative values alike for milk and its
manufactured products, has been to raise dairying gradually into
a much more important position as a branch of agriculture in
Britain than it has ever before occupied.

If consideration be given merely to the value of dairy produce
sold off the farms, the following estimates recently made by Mr. R.
Henry Rew^ may be quoted to show the present importance of
dairying relatively to other branches of agriculture. According to
these estimates, the value of the whole amount of agricultural
produce of the United Kingdom sold off the farms is £197,749,477,
while the value of the whole dairy produce of the United Kingdom
sold ofF the farms is £32,498,000.

The particular forms of dairj' produce from which the income is
derived are estimated by Mr. Rew to be as follows:—

Description of Produce. Quantity Sold off Farms in U.K. - Average Price. Total Value.

Milk, 576,000,000 galls. 6ld. per gall. £1.5,600,000

Butter, 2,000,000 cwts. 1125. per cwt. £11,760,000

Cheese, 2,000,000 „ 51s. id. „ £5,133,000

Total, £32,49.3,000

From these estimates it appears that one-sixth of the whole
income of British agriculture is derived from the sale of dairy
produce. There remains, in addition, a large proportion that is
consumed on the farm in the form of the milk supplied to calves,

^See Journal of Royal Agricultural Society, 1895.
(M175) J,

XVIU INTKODUCTION.

and the milk, butter, and cheese consumed by the farmer, his house-
hold, and the labourers on the farm.

The data of total produce, however, that have been quoted com-
prise the returns from extensive areas of mountain land the income
from which is realized, to by far the greatest extent, in the forms
of mutton and wool. Hence statistics that include the returns of
a large acreage of uncultivated land place dairying in a relatively
less important position than would be assigned to it if the income
derived from arable land only were taken into consideration. Its
exact position may perhaps, therefore, be more exactly appreciated
from the statistics bearing on the number and kinds of cattle
in Britain. The total number of cows and heifers, in milk or in
calf, in the United Kingdom in 1894, was 3,925,486, or considerably
more than one-third of the total number of cattle, at that time, in
the kingdom. The amount of milk yielded by this number may
be estimated at 1,766,468,700 gallons. If it be assumed that one-
eighth part of this yield of milk is used in rearing calves, there
would remain 1,545,660,112 gallons of milk for home consumption;
either in a raw condition as fresh milk, or in the manufactured
forms of butter and cheese. The science of dairying in the United
Kingdom, therefore, has for its subject-matter the management,
rearing, and feeding of about four millions of cows, and the pro-
duction, treatment, and sale of nearly eighteen hundred million
gallons of milk, and the whole jjrocesses of the manufacture of the
greater part of this enormous quantity into butter and cheese.

But great as the dairy industry is in Britain, its extent is, how-
ever, already rivalled by that of some of her colonies, and is far
exceeded by that of the United States of America. The total dairy
produce of the United Kingdom falls far short of the requirements
of her population; while that of the United States not only supplies
all that is required by her own greater population, but enables her
to export large quantities both of butter and of cheese. It was about
the end of the first quarter of the present century that the manu-
facture of dairy produce in the United States first attained to such
dimensions as to exceed the needs of the home population, and to
render new markets necessary. In 1826 the export of cheese to
England, then recently begun, amounted only to 735,399 lbs. In
1847 it had increased to 15,000,000 lbs.; and from that date till
about 1860, the total amount of cheese made in the United States
was estimated to be annually about 100,000,000 lbs. By that time.

INTRODUCTION. XIX

however, the system of making cheese in special factories, started in
1851, had begun to be widely adopted. In 1860 there were 23 such
factories. In 1866 these had increased to 500. In 1862-63 the
system that had been hitherto applied only to cheese-making was
also applied to butter-making, and the first butter factory was
opened. In 1866 there were 500 cheese factories, in addition to
butter factories. In 1884 the number of cheese and butter factories
had increased to over 4000. This raf)id extension of the factory
system was accompanied by a corresponding extension of dairy
farming. In the twenty-two years — from 1862 to 1884 — the butter
production of the United States is estimated to have increased from
500,000,000 lbs. to 1,500,000,000 lbs.

About 1861 a new branch of dairy manufacture began to attract
attention in the United States, viz., the manufacture of condensed
milk. This branch of the dairy industry proved so prosperous that
twenty years afterwards the quantity of milk treated in this fashion
amounted to about 60,000,000 lbs., and the industry is still extending.

A comparison of the available statistics for the period of thirty
years — from 1850 to 1880 — shows, perhaps, more clearly how much
more rapid was the gi'owth of dairy farming in the United States
than of even the rapidly increasing population. In 1850 the num-
ber of cows in the States was 6,392,044. In 1880 the number was
12,443,120. The butter made in 1850 amounted to 313,345,306 lbs.,
as compared with 806,672,071 lbs. in 1880. In 1850 the amount
of cheese made was 105,535,893 lbs. In 1880 it had increased to
243,157,850 lbs. The total value of the dairy produce of the
country, including milk, was estimated in 1880 to be about from
2 to 2| times as great as it w^as in 1850. In 1847 the export of
cheese to Britain amounted to 15,000,000 lbs. In 1894 it amounted
to 75,302,864 lbs., or five times as much, in addition to about 3i
million lbs. of butter.

In Canada the progress of the dairy industiy, though more
recent, has been even more rapid. In 1864 the dairy produce of
Canada was insufficient for the consumption of her population, and
imports were made from the United States. The population in the
thirty succeeding years has increased with great rapidity; j-et, not
only is the consumption of dairy produce fully met by home manu-
facture, but the exports to England in 1894 amounted to over 1000
tons of butter; while the exports of cheese amounted to over 67,000
tons, and constitute Canada by far the largest single source of

INTRODUCTION.

supply of the latter product to Britain. New cheese factories are
now being built, and there is every prospect, therefore, that the
future export will be still greater than it is at present.

In still more recent years a steady development of dairying has
occurred in Australia and New Zealand, owing to the fact that the
shipping of butter and cheese in good condition to this country has
been proved to be practicable. The exports from Australia have
proved so profitable to the producers that every year witnesses a
great increase in the quantity sent over; while the home demand of
these colonies for dairy produce is naturally becoming greater in
proportion to the rapid increase of population. Thus, in the first
six months of 1894, Australia exported to Britain 198,004 cwts. of
butter, while in the first .six months of 1895 the export had increased
to 241,665 cwts., or a growth in one year of over 20 per cent. The
total import of butter into England in 1894 was 32,000 tons more
than in 1889, and nearly half of that additional quantity came
from Australia. There is every probability in the near future that
the Australian export of dairy produce will assume much greater
dimensions; for the dairy industry in Australasia, now that an
export trade to Britain has become fairly established, is advancing
by leaps and bounds. A further illustration of this is found in the
fact that the export of butter, which was about 8f millions of lbs.
in 1891, had risen in 1892 to 6h millions of lbs. In 1891-92 the
number of cheese and butter factories existing was 74, while in the
following year there were 109. In the Province of Victoria alone,
there were in 1892-93 upwards of 400,000 milk cows, which yielded
over 120 millions of gallons of milk. Of this it has been estimated
that about one-third was consumed in its natural state, that about
75 millions of gallons were made into butter, and the remaining
five millions of gallons into cheese. In New Zealand the energetic
efforts of the Department of Agriculture have been very successfully
directed to the encouragement of dairying. Only a few years ago
there were no co-operative factories in existence, and, practically,
there was no export trade. Cheese and butter were made only on
a small scale, and almost entirely for local consumption. But in
1893 about 180 factories and creameries had become established,
and in 1894 these were increased by about thirty more. The pro-
duction was estimated in 1892-93 at 8,167,500 lbs. of cheese, and
6,722,303 lbs. of butter; while the exports alone in 1893 amounted
to 58,147 cwts. of butter, and 46,198 cwts. of cheese. There is every

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INTRODUCTION.

XXI

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xxii INTRODUCTION.

The total amount of the imports of dairy produce into Britain,
with the sources from which they come, is fully shown in the
table on p. 21.

It will be seen from the foregoing table that while the imports
of dairy produce into Britain from the United States are still large,
and while those from Canada and Australia are rapidly increasing,
there are also large, and, in some cases, still increasing, supplies
sent in from the several European countries which, for many years
before the development of the trans-oceanic trade, formed our chief
source of foreign supply.

So far as cheese and cured butter are concerned, the home manu-
facturer of these products has little advantage in the markets over
the foreign producer, except what is afforded by any injury that
may be done to the quality and flavour in the course of transit,
and the costs involved in the transport of the foreign product. This,
however, owing to the low rates of shipping freights that have ruled
for a number of j'ears, confers only a limited protection, and it is
now generally admitted that the only hope the British dairyman has
to compete successfully with the large foreign competition is by the
manufacture of produce of distinctly superior quality. This can
only be effected by giving the butter and cheese makers of this
country such a training as will enable them to attain to the highest
perfection in the practice of their delicate and difiicult art. Unfor-
tunately, up till quite recent years technical instruction in dairying
received almost no attention in Britain. An empirical art, differing
in various details of practice not only in every parish and county
but even on adjacent farms, was handed down from father to son,
or communicated from neighbour to neighbour in an unsystematic
and incomplete form that wholly prevented any general improve-
ment in the art of dairy manufacture. Consequently the manufac-
tured products were very variable, and often of an inferior character
and value.

While the art of dairying was thus imperfectly communicated,
the science of dairying, as it is now known, had till very recently
no existence. Thirty years ago there was practically no English
dairy literature. Appliances for the manufacture of butter and
cheese were few, and were imperfect. The principles that regulated
their manufacture were not understood, and the practice was accord-
ingly irregular and unsatisfactory. There were no dairy schools,
and no recognized means of obtaining intelligent instruction in

INTRODUCTION. XXIU

dairying. Neither can it be said, though great improvements have
taken place in recent years, that the old condition of things has yet
come to an end. A number of dairy schools have now indeed been
established, and have done excellent work. Systematic training
in the art of butter and cheese making can be obtained without
much difficulty in most parts of the country, and something is also
beginning to be generally understood of the principles on which
ttiese arts should be based. A dairy literature, largely drawn from
American, and indirectly from German, sources, but still to a great
extent empirical, has begun to be founded; and in the practice of
dairying, apart from increased knowledge or skill on the part of the
operator, much advantage has been derived from the possession of
modern and more suitable utensils.

But with all the progress that has been made in the past
twenty years, it is undeniable that our knowledge alike of dairy
practice and of dairy science is still far behind that of many of our
continental competitors. This is due in great part to the position
of greater importance the dairy industry holds in agricultural coun-
tries, such as Denmark and Holland, than in a country like Britain,
whose wealth is derived in large measure from minerals and manu-
factures. In all the countries, without exception, that contribute
materially to swell the imports of dairy produce into Britain, great
efforts have been put forth by the respective Governments to
develop and to carry to perfection manufactures on which the
wealth of these countries is so largely dependent. In Britain, up
till a few years ago, it was left wholly to private enterprise to
provide technical instruction in dairying, and even now the amount
contributed by Government to the assistance of dairy schools and
colleges imparting dairying instruction amounts to not more than a
few hundreds of pounds for the whole kingdom. In consequence
of this, little attention has been paid in Britain to a study of the
many important questions on which dairying demands the assistance
of the botanist, the chemist, and above all the bacteriologist. In
Denmark and Germany there are numerous and important dairy
schools and agricultural colleges, largely endowed and supported
by Government, in which the whole time of many able men is
devoted to dairy teaching, and to the investigation of the many
difficult problems that confront alike the practitioner of the dairy
art and the student of dairy science.

Hence it is that till recent years English agricultural literature

XXIV INTRODUCTION.

has been deficient in an adequate exposition of the science and
practice of dairying as now understood. Undoubtedly the most
valuable iiiformation available to the English reader on this subject
is to be found in the admirable Bulletins issued, from time to time,
by the United States Department of Agriculture, in which the
results of the more important researches in the domain of dairying
science are epitomized. We are also indebted to America for some
of the most recent improvements in methods and appliances, which
have greatly facilitated and improved the operations of the practical
art of dairying. It is to German and Scandinavian authorities,
however, that we have to turn for a complete exposition of the
science of dairying; and among continental authorities a first place
has for many years been assigned to Professor Fleischmann.

The English editors and translators cherish the hope that in
rendering Professor Fleischmann's comprehensive text-book on The
Science and Practice of Dairying available to the English reader
they may contribute something to the development of the most
enlightened dairy practice. A large number of new illustrations-
have been introduced into the English edition; while here and
there short passages have been omitted which possessed interest
for German readers only.^

^ The English editors desire to acknowledge their indebtedness to Dr. Paul Vieth, Director

of the Hameln Milchverschaftliche Institut, and to Mr. John R. Campbell, B.Sc, lecturer on

Dairying in the West of Scotland Technical College, Glasgow, for assistance in reading a.

portion of the work while in proof.

C. M. AIKMAN.

Tamiarij, 1896. R. PATRICK WRIGHT.

THE BOOK OF THE DAIEY.

CHAPTER I.

THE SECRETION, PROPERTIES, AND COMPOSITION OF MILK.

1. Definition.^ — -By milk,^ in the widest sense of the term, is
understood the secretion of the special glands of the female mammal.
It is a white, opaque liquid, of the character of an emulsion, with
a faint odour and

a slight flavour;
and it is produced
during a longer
or shorter period
after parturition.
It consists chiefly
of water, fat, case-
in, albumin, milk-
sugar, and mineral
salts, and is spe-
cially adapted for
the sustenance of
the young.

2. The Cow's
Udder. — -The par-
ticular glands in
which the milk ori-
ginates— the milk
glands — form the
most important

portion of the milk-secreting udder (see plates of cow's udder, figs.
1 and 2). The cow's udder is divided into two by a strong fibrous

Fig 3 —Structure of
Cow s Udder.

Bundle of Elastic Fibres (a), and Connective Tissue Fibres (6),
(x200.) (Furstenberg.)

^ By the term milk is always to be understood whole milk, and not skimmed milk.
(M175) 1 A

SCIENCE AND PRACTICE OF DAIRYING,

partition, running longitudinally. Each of the halves contains a
large milk-gland of a reddish-gray colour, oi- more correctly speak-
ino-, an accumulation of glandu-
lar structures, called the gland-
basket. In the case of adult
milk-cows, each milk-gland is
from 24 to 52 centimetres (9i
to 20| inches) in length, 16 to
31 centimetres (6|- to 12 J inches)
in depth, and 10 to 21 centimetres

Fig. 4.— Gland-lobules, e, Outlet tube,
(x 60.) (Furstenberg.)

Fig. 5.— Alveoli, d, Common duct, (x 200.)
(Furstenberg.)

(4 to 8 inches) in breadth. They contain, embedded in a white con-
nective tissue (fig. 3), the delicate gland-lobules (fig. 4), in which occur

Fig. 6.— Cylindrical Epithelial Cells, a, Cells grouped together; b, process of basement
membrane ;/, free cylindrical cells, (x 600.) (Fiirstenberg.)

numerous round cavities, the microscopic gland-lobules or alveoli
(fig. 5), which are terminal or lateral dilations of numerous and
extremely fine canals. When the cow is in milk the alveoli have a

THE UDDER.

length of about 12 to -20 millimetre ("0047 to '0078 inch) and a breadth
of "09 to'll millimetre ('OOSo to '0043 inch). According to Heidenhain,
the delicate tissue which sur-
rounds the alveoli consists of a
structureless membrane, the so-
called tunica jpropria, to the
inside of which is attached cel-
lular tissue. The internal surface
of this net- work of cells is further
lined with a continuous single
layer of epithelial cells (fig. 6).
The diameter of these cells, on an

average, is about '04 millimetre, and their form shows extraordinary
variations, according as the cow is in milk or not. In the latter case

Fig. 7. — Capillaries of Mammary Glands,
(x ISO.) (Fiirstenberg.)

Fig. 8. — Milk -cis-
tern and Outlet Tube
of Milk -gland, laid
open. Two tliirds of
natural size.

o, Basis of teat; h,
upper end of milk-
cistern; d, lower
end of same and
upper end of teat;
e', dilatation of
canal of the teat;
/, losette on end
of lower portion
of canal of teat;
h, small, and o,
large gland-ducts.
(Fiirstenberg.)

the epithelial cells are low and flat, while in the former they are swollen
and protrude comparatively far into the alveolian cavity. On the
outside, the membrane of the gland-lobules is surrounded by a highly

SCIENCE AND PRACTICE OF DAIRYING.

developed net-work of capillary vessels (fig. 7), in vi^hich the
material for the formation of milk circulates through numerous
lymph tracts, and also by means of very fine nerve fibres, which
promote special physiological functions of the glands. The duct-
lets, of which the alveoli are the dilations,
unite together among themselves in gradu-
ally ever-widening ducts — the milk-ducts,
— and end eventually in lare^e hollow cavi-
/-^/..t* />y r^^'^"^^ ties, the so-called 'niilk-cisterns or Tnilk-
^■^ii, f Ajm'.'^z-.m reservoirs (figs. 8-11). Four of these, which
lie above the teats, are present in each
udder, two on each side. The connective
tissue, wfiicli encloses the lobules of the
gland, and which unites them to the large
closed milk -glands, is
enveloped in adipose
tissue, and this in turn
is covered by the skin,
which is interspersed
with many blood-vessels.
On the udder there are,
as a rule, four teats
(fig. 12), corresponding
to the four milk-cisterns,
from which milk can
be drawn; while behind them frequently occur
some undeveloped teats, very rarely provided
with outlet tubes. The duct of the teat
(figs. 13-16) is about 4 millimetres in length,
and is shut at its end by means of a smooth
sphincter muscle. The capacity of both milk-
glands, together with that of the four milk-
reservoirs, in the udder of an average cow, after
milking, may be stated at about 6 to 7 cubic
decimetres.^ The internal space of the udder
available for retaining milk, however, does not
admit of accurate estimation, owing to the great elasticity of the
surrounding tissue. The udder of a cow of ordinary milking capa-
city, carefully examined by us after slaughter, was found to have a

1 About lOi to 11| pints.

Fig. 9.— Plaster of Paris Cast of
the Posterior Milli-cistern, witli
the Canal of the Teat of the left
side, from the Udder of an Ayr-
shire Cow, yielding 1200 to 1300
quarts of milk yearly. Half
natural size. (Fiirstenberg.)

Fig. 10 —Plaster of Paris
Cast of the Posterior Milk-
cistern, with the Canal of
the left side of the Udder
of a Dutch Cow, yielding
3000 quarts of milk yearly
Half natural size. (Fiii'sten-
berg.)

THE UDDER.

total storage capacity of about 3 cubic decimetres; and for one milk-
cistern, on an average, '25 cubic decimetre.

It is unnecessary, for the purposes of this book, to enter into a detailed
description of the distribution of the muscles, ligaments, adipose tissue,
nerves, blood and lymph vessels, and of the skin and hair of the udder.

Fia

11.— Plaster of Pan's Cast of the Milk-cistern and Milk-ducts of the posterior half of
the Milk-gland of a Dutch Cow. Natural size. (Fiirstenberg.)

Four milk-glands are often spoken of, as if there Avere two on each side
of the udder, an assumption warranted neither by the course of the milk-
ducts leading to the two milk-cisterns, situated on the same side, nor by
any other anatomical structure.

The physiological action which gives rise to the secretion of milk in
the udder has, as its chief centre, the above described gland-lobules, which
are covered inside with an epithelial cell-layer, and outside with a net-work

SCIENCE AND PRACTICE OF DAIRYING.

of capillary vessels. The practical importance of this is that the amount
and quality of the milk secretion principally dej)ends on the number of
gland-lobules present in the udder, and the number
and course of the vesicles distributing the blood-
stream through the milk-organ. The difference in
the milking qualities of different cows is primarily due,
therefore, to the inherited individual characteristics.

3. Formation of Milk. — • We conclude that,
since none of the organic constituents, present

Fig. 12. — Plaster of Paris
Cast of the Canal traversing
the Teat and Nipple. Na-
tural size.

a. Basis of teat; d, lower
end of milk-cistern, and
upper end of nipple; e,
small gland-ducts ; e', di-
latations of the canal of
the teat; /, rosette on
the lower end of canal of
the teat; g, lower end of
outlet tube of milk-gland.
(Fiirstenberg.)

in milk, is present in the
blood, they are all formed
in the gland-lobules from
the circulating fluids,
the blood and the lymph,
found in the udder. But
the changes which take
place in this operation
are little understood.
Before entering into a
description of them, so far as they are at present known, it should
be pointed out that the milk-glands are not equally active during

Fig. 13.— Section of Membrane of Lower and Narrow portion
of the Canal of the Teat, (x 85.) (Fiirstenberg.)

I, Epidermis; e, superficial layers of epidermis; d, sebaceous
gland; /, /, section of bundle of muscle-fibres.

FORMATION OF MILK.

the whole hfetime of the animal. Their action is broken by alter-
nate periods of rest. Even during the same lactation period the
work of the glands does not continue at the same rate, but varies,

.^#5^.

Fig. 14.— Section of Sebaceous Gland, a, Sebaceous gland; 6, superficial layer of epidermis;
c, epidermis ; rf, horny layer, (x 100.) (Fiirstenberg.)

on the one hand, with the period of lactation, and, on the other
hand, according- to the surrounding physical conditions.

According to the theory regarding the origin of milk which obtained
prior to the year 1840, it was believed that the milk-glands acted as a
sort of filter with a wide surface, for certain constituents of the blood, and
that in milk we were dealing with a filtrant from the blood, the amount

^^^ ./

■""^^i ^-^"r '■.'^m ^

Fig. 15.— Tallow- Follicle of the Nipple, (x 100.)
a, Outlet ducts. (Fiirstenberg.)

./^^TpS^

Fig. 16. —Tallow Follicle of
Nipple, (x 180.) (Fiirstenberg.)

and quality of which was determined solely by the amount and quality of
the food. When, however, it had been proved, by chemical investigation,
that not one of the organic constituents of milk occurred ready formed in
the blood, but that they were all formed in the milk-gland, this theory
had to be abandoned.

The labours, during the last forty years, of different physiologists, such

8 SCIENCE AND PRACTICE OF DAIRYING.

as Nasse, Henle, Van Bueren, Rheinhardt, H, Meyer, &c., who have
carried out researches on the origin of the fat globules in milk, have
demonstrated the fact, that, of all the milk constituents, fat alone, in the
form of the fatty cell, is recognizable by the aid of the microscope. One
of the first who submitted the gland substance to careful microscopic
investigation with a view of elaborating a theory of milk production was
Will of Erlangen. By means of his investigations, the theory first dis-
tinctly expressed by Virchow, regarding the origin of milk, Avas formulated.
According to this theory, the milk-gland must be regarded, morphologically,
as a kind of sebaceous gland. The separation of milk in it takes place
just in the same way as that of tallow in the many-layered epithelium of
the alveoli; it represents, in reality, the pathological occurrence of a
fatty degeneration of the epithelium of the glands. Voit, in his work
on the formation of fat in the animal body, supported this theory, which
rapidly became popular. He regarded milk as a liquid cell substance — as
the liquefied cell substance of the milk -glands. By the microscopical
investigations of Heidenhain, Voit's conclusions were seriously called in
question. According to these researches, the epithelial cells of the alveoli
of the glands are only present in one layer; the colostrum bodies possess
no significance for the morphology of the formation of milk ; and the
epithelial cells of the secreting gland are not subject to fatty degenera-
tion. What takes place is rather that their free ends suffer degeneration,
and that a renewal of the cell material takes place at the opposite end.
C. Partsch also comes to the conclusion, from microscopical observations,
that the formation of fat in the epithelium of the gland does not exhibit
the slightest resemblance to the formation of fat in the sebaceous cell.
As Partsch nowhere met with cells exhibiting fatty degeneration in the
epithelial layer of the active milk-glands, and always found the fat on
the points of the epithelial cells in single large drops, and the increase in
the percentage of albumin in the cells accompanied by an increase in the
separation of fat, he regarded it as not proven that the fat of milk is an
example of retrogressive metamorphosis of the epithelial cell, but rather
that it is separated through the special activity of the cell in the true sense
of the word.

Subsequently Heidenhain, as well as Nissen, advanced the opinion that
during the period of lactation the nuclei of the gland -cells constantly
increase and successively degenerate. They are then extruded from the
cells in which they have been formed, and are finally broken up in the
cavities of the glandular vesicles.

This explains at the same time the method in which the nucleo-
albumin, discovered by Lubavin and Hammarsten to be a constituent of
milk, enters it.

FORMATION OF MILK. 9

Bizzozero and Vassate, by their elaborate investigations on the increase
of the constituents of the growing glands of the mammals, and on their
capacity for undergoing regeneration when fully developed, came to the
conclusion that in milk we have not to deal Avith a secretion of the gland-
cells. At the same time they established the fact that no evidence exists
of a direct or indirect division of the epithelium of the glands during
lactation, and hence that the process of milk formation is independent
of the destruction of cells or of cell nuclei, as Heidenhain and Nissen had
affirmed.

Rauber regards milk-fat as a decomposition product of the lymph
bodies of the blood, which, as he believes, can be proved to float in the
gland alveoli, and expresses the opinion that the source of the caseous
matter is also to be sought for in the lymph bodies. According to him,
a single principle runs through the whole scheme of nourishment of the
young mammal, in so far as the lymph bodies already play an important
part in the nourishment of the egg and of the embryo. With the birth
of the young mammal, exit for the lymph bodies on the uterus is closed
and a new exit is opened in the milk-glands, so that one and the same
material is used for the nourishment of the egg and the embryo as for
the nourishment of the young mammal. Through the above-mentioned
researches of Heidenhain, Parstch, Bizzozero, and Vassate, the basis of
Rauber's conclusions has been for the most part destroyed.

According to another series of investigations on milk formation, the
origin of the different organic constituents of milk in the milk-gland is to
be traced to certain maternal substances, and is carried out by certain
ferments. Hoppe-Seyler, at the end of 1850, made the observation that
if milk be allowed to stand exposed to the air, small quantities of fat,
probably from protein matter, were formed. This formation of fat is
accompanied by the absorption of oxygen and the evolution of carbonic acid
gas. This observation has been confirmed by Kemmerich and Soubotin.
It is a matter of dispute, however, whether this process, if it does take
place, is to be regarded as a physiological one, or whether it is to be
accounted for by the action of bacteria. To decide this point, Kemmerich
in 1867 first introduced a method of research which consists in observing
the behaviour of the secretion from the milk-gland at the temperature of
the body. Supported by the results of a number of experiments, Kemme-
rich believed he had established the fact that during the secretion of
the milk at animal heat a physiological process goes on, in which caseous
matter is formed at the expense of a fermentative decomposition of
albumin. This theory of Kemmerich, which in the main Avas also
adopted by Zahn, was totally disproved in the year 1882. Schmidt-
Miihlheim, by means of careful researches, proved that during the decom-

10 SCIENCE AND PRACTICE OF DAIRYING,

position of milk at animal heat the percentage of its albumin remains^
unaltered, and that its percentage of caseous matter, instead of becoming
increased, is rather diminished, while the percentage of peptones present
in it increases. Following the researches of Kemmerich, Danhardt
endeavoured in 1870 to separate a ferment from the milk-gland of a
guinea-pig. In this he succeeded, and with it he was able, by digesting
in it a dilute and slightly alkaline solution of egg albumin, to obtain a
body having the properties of casein. In 1833, H. Thierf elder published
a work which likewise aimed at tracing the formation of the constituents
of milk to maternal substances and ferments in the milk-gland and in
the milk. Thierfelder believed that his researches pointed to the fact
that during the digestion of the milk-gland at animal heat, a body (perhaps
milk-sugar) was formed by fermentation processes, which not only pos-
sessed the reducing poAver, but also the properties of casein (perhaps casein
itself). The researches of Hoppe-Seyler, Kemmerich, Soubotin, Zahn,
Danhardt, and Thierfelder, however, which have been mentioned above,
have collectively raised the important objection, that these experiments'
Avere not carried out with sufficient care, to exclude the possibility or
probability of contamination Avith micro-organisms, through want of
cleanliness in the materials experimented with.

What takes place in the formation of milk in the udder is^.
therefore, not as yet well understood. We do not know to what
extent the constituents of the blood, the fat, the albuminoids, the
carbohydrates, as well as the lymph bodies and the substance form-
ing the epithelial cells of the alveoli of the glands, are utilized in
the formation of the organic constituents of milk; and still less do'
we know the changes that take place in the materials which are
converted into the constituents of the milk. It may be regarded as-
probable that milk-fat is a secretion of the epithelial cells of the
gland vesicles of the udder, and that it is derived from difi'erent
sources, viz., partly from the fat present in the blood, and partly
from the products of the changes that take place in the animal
tissue. With regard to the albuminoids, the milk-sugar, and the
other constituents of milk, despite many researches, little is known.
All the most recent scientific investigations, combined with num-
berless practical observations of cow-feeders, so far agree that the
secretion of milk depends primarily on the direct influence of the
greater or less activity, as well as the eflicienc}'-, of the milk-gland,
and on the particular conditions under which the animal lives; and
secondly, on the kind of food and condition of the blood. This

PROPERTIES OF MILK. 11

conclusion, although of a very general nature, is nevertheless of
great practical importance.

4. Properties of Milk. — -Milk, obtained under the usual condi-
tions, is a pure white fluid, which appears completely opaque when in
large quantities. In thin layers, however, it is slightly transparent.
It possesses a slight smell, similar to the exhalation from the skin
of the cow, and is of a mild, rich, slightly sweetish taste. It
exhibits a slight amphoteric (alkaline and acid) reaction, and can
be boiled without coagulating. If left standing undisturbed at the
usual temperature, a collection of microscopically minute globules
of fat rises to its surface, and forms a layer of cream. When kept
standing some time longer, the milk spontaneously coagulates.
Previous to coagulation the milk is in such a condition that,
although at ordinary temperatures it undergoes no change, yet on
boiling, or even on slightly heating it, the milk immediately
changes. Even at the ordinary temperature it is coagulated on
the addition of a minute quantity of a strong acid, or on the addi-
tion of carbonic acid.

On milk standing at a temperature of over 50° C, a skin is
formed, consisting of coagulated albuminous matter, enclosing small
quantities of the other milk constituents. As often as this skin is
removed it renews itself. It is the formation of this skin on the
surface of the milk that causes it when it is boiled to froth over so
easily. Boiling imparts to the milk a peculiar taste and smell
(cooked taste).

The chief constituents which milk contains are water, albuminous
bodies (proteids), butter-fat, milk-sugar, and mineral salts. Milk
has always a greater specific gravity than water. In the case of
the milk of single cows, or the milk from single milkings, its specific
gravity at 15° C rarely exceeds the limits of 1"028 and 1034, and
a mixture of the milk of five or more cows, or of two or three
milkings, rarely exceeds a specific gravity of 1029 and 1033. On
an average its specific gravity may be stated at 1"0312. The
specific gravity of the total solids of milk varies between 1"30 and
1*40, and that of the non-fatty solids is almost always constant,
and may be stated with approximate accuracy at 16 at 15° C.

The opacity and colour of milk is due to the numberless fatty globules
suspended in it, as well as to a portion of its albuminoids and mineral
matter, which are also in a state of suspension. According to Soxhlet,

12 SCIENCE AND PRACTICE OF DAIRYING.

the amphoteric reaction of milk is caused by the presence in it of neutral
and acid phosphates and carbonates of the alkalies. By warming the milk
the alkaline reaction becomes more pronounced. Warming, however, has
no influence on the acid reaction. To phenol-phthalein milk only shows an
alkaline reaction after it has been neutralized with a certain amount of
alkali. As a rule 100 c.c. of fresh milk require about 7 c.c. of a ^ normal
soda solution for the alkaline reaction. In order to determine the acidity
in fresh milk caused by the acid phosphate, Soxhlet and Henkel treat
50 c.c. of milk with 2 c.c. of an alcoholic 2 per cent phenol-phthalein
solution, and titrate with a ^ normal soda solution. The number of c.c.
required serve as an indication of the acidity. By the addition of diluted
acids milk can be immediately coagulated, and, in a somewhat longer time,
by means of a strong rennet solution. Dilute lactic acid and rennet
change the milk into a coagulated adhesive mass. Acetic and diluted
mineral acids, under similar conditions, produce flocculent coagulation.
By Avarming milk at 50° C, or at higher temperatures, it undergoes
changes which specially affect its proteids, as well as its taste and colour.
Under such conditions the addition of diluted acids does not produce a
lumpy coagulation, but a finely flocculent and pulpy one. The milk is
also rendered much more sensitive to the action of rennet, which, under
certain conditions, exerts its full coagulating influence. Milk coagulated at
a temperature of 130° to 140° C. assumes the peculiar flavour of cooked milk,
and becomes slightly yellowish or yellowish brown in colour. The higher
milk is heated betAveen the limits of 50° C. and 140° C, the more quickly do
the above described changes take place, and the shorter is the time within
which increased temperature produces the various changes. It is obvious
that heating milk to 100° C. can only be accomplished in a closed vessel.

The properties of the proteids of milk are dependent, in the first place,
on the nature of the chemical combinations of the mineral constituents of
milk, and especially of the lime salts. If, as is actually the case, the
constitution of the mineral salts of milk is changed under the influence of
high temperatures, and if a portion of the soluble lime salts is converted
and precipitated into an insoluble condition, it naturally follows that the
condition of the proteids also undergoes change.

The peculiar smell and flavour of milk strongly heated is very pro-
bably connected with the small quantities of sulphuretted hydrogen which
have been proved to be present in boiled milk. (Fresh milk, treated with
tincture of guaiacum, assumes a blue colour, while boiled milk does not
show this reaction.)

The change of colour which takes place on heating milk for some time
at temperatures over 80° C, and which increases the higher the tempera-
ture and the longer the duration of the exposure to such temperatures,

PROPERTIES OF MILK, 13

is explained by the fact that milk-sugar undergoes incipient decomposi-
tion, producing small quantities of yellow and brown substances (lacto-
caramel 1). Continuous heating affects the fineness of the state of division
of the fat of the milk. The microscopically small fatty globules become
partly dissolved and run together, forming large drops of fat easily visible
to the naked eye. The boiling point of milk is a fraction of a degree
higher, and the freezing point a fraction of a degree lower, than the
boiling and freezing points of water. The maximum density point of
milk is not 4 'OS" C, as is the case with water, but - '3° C. Possibly these
conditions vary with the percentage of solids in the milk, especially of fat,
but no experiments have been made on this point. The behaviour of
milk under the influence of the electric current also requires investigation.
The question of how far electricity might be beneficially applied in dairy-
ing still awaits investigation.

The coefficient of expansion of milk increases with the temperature,
as well as with the percentage of total solids, and, between the tempera-
tures of 5° and 15° C, is undoubtedly greater than that of water. It
follows from this that milk loses more and more of its limpidity as the
temperature is reduced, and at temperatures below 10° C. it assumes a
slightly viscous condition, and maintains this viscosity on its surface.
According to experiments by the author, the variation in the volume of
ordinary cows' milk (of a specific gravity 1"0315 at 15° C.) at different
temperatures is as follows : — ■

1,000,000 volumes at 0° C.

1,000,030

1° C.

1,000,391

4° C.

1,001,273

10° c.

1,002,134

15° C.

1,003,800

20^ C.

1,006,414

30° C.

1,014,277

50° C.

1,019,243

-60° C.

The absorptive capacity of milk for heat (latent heat) is not a constant
quantity, but depends, according to experiments carried out by the author
in 1874, on the quantity of total solids. For milk of ordinary chemical
composition it may be stated at "847, water being taken as I'OOO.

When exposed to the action of frost the larger portion of the milk
is frozen, a small portion only remaining liquid. The portion remaining
liquid is richer in solid matter than the portion frozen.

When milk is subjected to dialysis only a portion of the mineral matter
and the milk-sugar diffuse through, and possibly also a trace of nitrogenous
matter.

14 SCIENCE AND PRACTICE OF DAIRYING,

If a candle light be looked at through a thin layer of milk, the flame
usually appears yellow, but occasionally it appears of a reddish colour.
The thickness of the milk layer with which this takes place is dependent
upon the percentage of fat the milk contains, but is not directly propor-
tional to its amount, as it is also dependent upon the size of the fatty
globules present. The same quantity of fat retards more light Avhen it is
in the form of very small globules, than when it is in the form of larger
globules. It is for this reason that the determination of fat by the so-called
optical method is so very unreliable.

According to Jorgensen, the refractive index of milk serum lies between
1'3470 and r3515, and that of curd, coagulated by rennet, between 1'3433
and 1-3465.

It may be taken for granted, that the suspended matters of milk —
the fat, the nitrogenous substances, and the phosphate of lime — have the
same effect upon the chemical balance and on the hydrometer as if they
were in solution, although this does not necessarily follow as a self-evident
fact. Mach has shown that very finely divided bodies suspended in liquids
only exert their weight on the balance and areometer when they are either
at rest, or are moving Avith a regular speed. That these conditions are
fulfilled by the substances in suspension in milk is proved by the fact that
tests of the specific gravity of milk conducted in a most careful way, both
Avith the balance and Avith the hydrometer, give constant and perfectly
concurrent results.

It is noteAvorthy that milk, rich in fat, despite this richness in a
constituent of low specific gravity, does not generally exhibit a Ioav specific
gravity, nor milk poor in fat, a high specific graA'ity. This is OAving to the
fact that milk rich in fat is also rich in the other solid constituents, and
milk poor in fat is also poor in the other constituents. The specific gravity
of milk is always exactly proportional to the percentage of the non-fatty
solids. W. Thorner has investigated the resistance Avhich milk off'ers to
the electric current, and has found that the resistance of pure milk is not
an absolutely constant quantity. It is more or less increased by the
addition of Avater, diminishes Avith increasing acidity of the milk, and is
independent of the amount of fat it contains.

5. The Nitrogenous Matter in Milk. — This forms from 2-5 per
cent to 4'2 per cent — on an average 3'5 per cent — of the contents of
milk, and consists of substances of the nature of protein — the
so-called albuminoids. Duclaux's theory, that there is only one
-albuminoid in milk, is not consistent Avith the properties exhibited
by it. It is highly probable that milk contains three albuminoids —
casein, lactalbumin, and globulin — the casein being very much in

THE NITROGENOUS MATTER IN MILK. 15

excess of the others, and forming about 80 per cent of the total nitro-
genous compounds. Casein contains nuclein, a substance which is
not found in albumin, and which is characteristic of the cell nucleus.
It is rich in phosphorus, and strongly resists the action of pepsin
solutions. While it has the properties of an acid it is also able to
form saline compounds with bases, and is insoluble in water. On
the other hand, its compound with lime (calcium oxide) — in which
form it is present in milk — is soluble in water, or, more correctly
speaking, forms with water a bulky colloidal substance, which, when
milk is filtered through porous clay cells, does not pass into the
filtrate, and is not absorbed when milk is passed through porous
clay plates (Lehmann plates). The other albuminoids present in
milk are in true solution, i.e. when milk is filtered through porous clay
■cells they pass into the filtrate. In order to distinguish the casein
present in milk, which is in combination with lime, from pure casein,
it is called the caseous matter of milk. A very small portion of this
caseous matter, at most from "5 to 1 per cent, is removed from the
milk in the separators by centrifugal force, and forms the chief
constituent of the separator residue. When milk spontaneously
becomes sour, or is coagulated by the addition of acids, the lime
which it contains is separated from the caseous matter, and the
insoluble casein coagulates in the form of a clot. Under the action
of rennet, casein is converted into paracasein and curd protein. The
former, provided there is a sufficiency of lime salts present to effect
precipitation, is precipitated, and the latter remains in solution. In
both cases the clots thus formed enclose mechanically the particles
of fat present in the milk. When milk is coagulated by rennet, or
by the addition of substances which act as dehydrating agents, as,
for example, neutral salts or alcohol, the precipitate thrown down
contains not merely the fat, but also the. calcium phosphate in sus-
pension in the milk. If, on the other hand, milk is coagulated by
acids, or is allowed to become spontaneously sour, the greater portion
of the suspended mineral salts is left in solution, and the coagulated
casein contains only minute quantities of calcium phosphate.

The extent to which the caseous matter is precipitated varies in
the case of milk derived from different sources. Even in the same
sample of milk the caseous matter is not coagulated to the same
extent, even although the conditions under which coagulation takes
place are similar. As a rule, the coagulation obtained is greatest
immediately after milking, and diminishes with the lapse of time.

16 SCIENCE AND PRACTICE OF DAIRYING.

It is found that in milk standing for a time after milking, a coagu-
lation of the caseous matter takes place. The result of this is, that
the specific gravity of perfectly fresh milk, determined by means of
the hydrometer at 15° C, will always be found to be higher, to
the extent of from '5 to one thousandth than in the same milk
when rapidly cooled or allowed to stand for some hours. For this
reason special precautions ought to be taken in testing the specific
gravity of milk with the hydrometer. The extent to which the
precipitation of the caseous matter takes place depends on the tem-
perature— with a rising temperature it is increased, while with a
falling temperature it is diminished. For this reason, in the raising
of cream, equable low temperatures in the milk are not favourable,
because with low temperatures the fatty globules meet with increased
resistance in rising to the top.

Among the more important early researches on the nature of the
albuminoids and caseous matter of milk may be mentioned those of
Scherer, Nasse, Schiitzenherger, Knop, and others. The theory first
advanced by Scherer in 1841, which was held for thirty years, that the
caseous matter is in the form of potassium albuminate, has now been com-
pletely controverted. The view which has been held on the subject of the
nitrogenous matter in milk, since 1875, is based on the reactions exhibited
by milk with certain reagents.

If milk be precipitated, at the ordinary temperature, by dilute vinegar,
the larger portion of the nitrogenous matter is thrown down as a precipi-
tate. If the filtrate from this precipitate be heated, a second precipitate is
formed. The filtrate from this precipitate again gives a third precipitate
with alcohol; and by treating the filtrate from this last precipitate with
Millon's reagent, a fourth precipitate is obtained. It was consequently
believed that each one of these precipitates represented a separate
albuminoid, and these were distinguished as casein, albumin, albuminose
(Bouchardat and Quevenne), and lactoprotein (Millon and Commaille).

But it may be pointed out, that the behaviour of the milk, as above
described, admits equally of the view which regards the nitrogenous
substance of the milk as consisting of one substance only. It merely
practically proves that the nitrogenous substance of the milk, at ordinary
temperatures, is only partially precipitated by vinegar, more completely
by vinegar at boiling temperature, and still more perfectly by alcohol, and
that it is completely precipitated by certain salts of the heavy metals. No
necessity exists, for inferring, on these grounds, the existence of four
separate albuminoid bodies, any more than for supposing, for example,
Avithout further evidence, that there are four diff'erent kinds of lime,

52-95

7-05

15-65

22-78

0-72

0-85

THE NITROGENOUS MATTER IN MILK. 17

because lime is more or less perfectly precipitated from its solutions, by
different reagents, under different circumstances.

An important advance in our knowledge of the nature of the nitro-
genous matter of milk was made by the comprehensive and thorough
researches of 0. Hammarsten of Upsala. These researches render it highly
probable, that the large amount of albuminous matter which is precipi-
tated, at ordinary temperatures, by acetic acid, and which has long been
known as casein, is a characteristic albuminoid, with distinctive properties,
and that in addition to this body there are two other albuminoids present
in milk, viz., ladalbuviin, and, in very small quantities, globulin.
Hammarsten considers casein a nucleo-albumin— a body in which nuclein
is in complex chemical combination with albumin. According to him, the
chemical composition of pure casein is as follows : —

Carbon,

Hydrogen,

Nitrogen,

Oxygen,

Sulphur,

Phosphorus,

100-00

His lactalbumin contains neither nuclein nor phosphorus, and has 1*7
per cent of sulphur — that is, about as much as pure egg-albumin, which
contains 1-6 per cent. The lactoprotein of Millon and Commaille,
Hammarsten considers to be made up of a mixture of imperfectly preci-
pitated casein, and small quantities of albumin, partially converted into
syntonin and peptones. He further holds that the acid character of casein
is due to the fact that the condition of the casein in milk depends on
the calcium phosphate, and that the coagulation of milk cannot take place
without calcium phosphate. What the nature of the relationship existing
between the casein and the calcium phosphate is, he does not state.
Eugling's assertion, that the casein is always present in milk in chemical
combination with normal calcium phosphate, rests on observations which,
on examination, do not appear to be reliable.

According to Danilewski and Kadenhausen, milk contains no fewer
than seven different nitrogenous bodies, Avhich belong to the albuminoid
group, or are nearly related to it. Their highly artificial theory that casein
is a mixture of caseo-albumin and caseo-protoalbumin bodies lacks sufficient
proof.

More recently Duclaux has again revived the original theory, that
the albumin and the remaining nitrogenous substances are not really

( M 175 ) B

18 SCIENCE AND PRACTICE OF DAIRYING.

different, and that in milk there is only one albuminoid, viz., casein.
According to him, the changes which the milk undergoes, as above
described, are to be accounted for by the fact that casein in solution,
and when precipitated, acts differently. Lactoprotein and albumin are,
as Duclaux assumes, nothing else than casein in conditions more or less
soluble in water.

Among the most recent investigations on the nature of the nitrogenous
substance of milk, undoubtedly the most valuable work is that by Soldner,
entitled, The Salts of Milk and their Relations to the Conditions of Casein.

Soldner opposes to Hammarsten's vaguely expressed theory that casein
and calcium phosphate are present in the milk in solution, the exact and
well authenticated theory that the caseous substance of the milk must be
regarded as consisting of a neutral calcium compound of casein, and that
the action of the rennet does not depend on the presence of calcium phos-
phate, but chiefly on the presence of a soluble lime salt. Further on, in
the Chapter on the Preparation of Casein, we will have an opportunity of
again referring to Soldner's work.

Within the limits of 0° to 100° C, the amount of acid or neutral salts
which is necessary to effect the precipitation of casein, decreases with an
increase of temperature ; Avhile within the limits of 0° and 42° C, the
length of time which elapses before the spontaneous coagulation of the
milk takes place also decreases with the increase of temperature. Normal
sodium carbonate, caustic alkalies, normal sodium phosphate, and other salts,
Avhich effect the precipitation of solutions of calcium phosphate, although
they are themselves solvents of casein, yet in the process of coagulation
cause its precipitation. This is effected by the fat and casein becoming
mechanically entangled with the precipitated tricalcium phosphate, and
carried down with it. The addition to milk of a small quantity of a
caustic alkali, or of a carbonate of the alkalies, diminishes its opacity.

Solutions of caseous matter, on standing at temperatures of over 50° C,
become covered with a skin, and Avhen heated in close air-tight vessels to
130° to 140° C. become coagulated, and exhibit greater laevo-rotatory pro-
perties than solutions of albumin; and are precipitated by dilute acids, by
most of the salts of the heavy metals, by alcohol, and by rennet, provided
the dissolved calcium salts necessary for this purpose are present. The
heat equivalent of casein, according to Stohmann's investigations, amounts
to 5715 calories per gram of substance. Schiibler gives the specific gravity
of fresh casein as I'lOO, and of boiled casein as 1*259. According to the
investigations of the author, the pure nitrogenous matter of milk at 15° C.
has a specific gravity of r486.

Of equal interest, both from a theoretical and practical point of view,
is the relationship which exists between the nitrogenous constituents of

MILK-FAT. 19

milk on the one hand, and the mineral salts on the other. All influences
that are able to change the constitution of the salts of milk, such as the
prolonged action of high temperature, the evolution of carbonic acid from
milk fresh from the cow, the formation of lactic acid through fermentation,
the diseases of cows, their feeding, the time since calving, the age of the
cow, the boiling of milk, &c., also exercise an influence on the nature and
properties of the nitrogenous substances, especially on the caseous matter.
They alter to a slight extent the specific gravity of the milk, cause the
rising of the cream to take place either more rapidly or more slowly, and
make the milk more susceptible, less susceptible, or entirely unsusceptible,
to the action of rennet. They favour or retard its coagulation by acids,
and influence the nature of the curd jJi'oduced by the action of rennet or
acids.

6. Milk-fat (Butter-fat). — Milk-fat is present in milk in a very
fine state of division, viz., in the form of innumerable little drops or
globules of varying size, which are all oooo

of them invisible to the naked eye. o°o^ooo^°"

In the milk of cows the diameter of
the smallest and the largest of these
globules is respectively '0016 mm. and
•01 mm., so that the former is almost

625 times as small as the latter (fig. 17). "^*^0°°

The globules vary in size between ^^

,, T -J. 1 i. • Fig. 17.— Milk Globules. (X 300.) (Fursten-

these limits, and are present m vary- y^erg.) «, smaii ones found in miik
ing proportions. It appears probable ffcre^T'''"""' *' ^*'^' °"'' ^""""^
that tlie number of the different-sized

globules is in inverse ratio to their size, or, what is the same thing,
the weight of the sum of all the globules of the same size is
equal for the entire number of different sizes. At anyrate, the
microscopical examination of milk shows that the smaller the
globules the more numerous they are.

Under the ordinary conditions which prevail in Germany, the
percentage of fat in cows' milk, with very few exceptions, varies
between 2*5 and 4*5, and may be stated, on an average, at 3*4. For
the north and north-east of Germany, the average may be stated at
3-25.1

1 The average of aU complete American analyses of milk made up, 1891, is 4% of fat, the
limits being from 2 to 8%; while the average of over one hundred and twenty thousand
samples of English milk, as analysed by Dr. Vieth, i.s i'l^ of fat. (See Aikman's Milk: lis
Nature and Compositioa (A. k, C. Black), p. 11.) — Enylish Editors.

20 SCIENCE AND PRACTICE OF DAIRYING.

The fat globules are not surrounded with a membranous en-
velope. Owing to the action of molecular force, the little globules
are surrounded by a thin watery covering of serum, and act very
much as if they were actually surrounded by a membrane. The
influence of the molecular force, manifested in all emulsions,
explains why the fat globules in a layer of cream, at ordinary
temperatures, do not cohere, and explains why the application of
a not inconsiderable force in churning is required to bring them
together, and why they offer some resistance to the solvent action
of ether.

As the specific gravity of fat is less than that of milk serum,
all the fat globules are under the influence of a force which compels
them to ascend to the surface. It has been calculated that this
influence acts very rapidly. Thus by keeping a layer of milk 10 to
20 cc. in depth for a day and a night, at rest and at ordinary tem-
perature, about four-fifths of its total fat comes to the surface. The
smallest globules containing the rest of the fat do not experience a
motion of their own, because their tendency to rise is no longer
sufficient to overcome the opposition offered by the friction of the
coagulated casein in which they are enveloped.

The use of separators has done much to increase the yield of
fat. By their aid all the fat may be extracted to within 5 per cent
from the milk or cream treated. It is in the highest degree probable
that the fat globules, both in milk and cream, are present in a liquid
form at ordinary temperatures, and that they are only converted
into a solid form by the action of churning.

The superior digestibility of milk-fat, when partaken of in the
form of milk, cream or butter, may be traced to the extreme
minuteness of its state of division.

The composition of the fat of milk does not resemble that of fat
obtained from other sources. It is of a much less simple chemical
nature than that of other fats. Butter is distinguished from them
by its more agreeable taste. The soft condition of butter fat at
ordinary temperatures renders it in a special degree suitable for
spreading on bread. As is the case with other organic substances
of complex composition, it is readily liable to change, is less easily
preserved than the other edible fats, and quickly loses its fine flavour
under unfavourable circumstances. These special properties of
milk-fat render butter the most valued and the most highly prized
of all fats.

MILK-FAT. 2 1

The fat globules were first discovered and described in 1697 by A. Von
Lesuwenhoeck. The number of these fat globules in a drop of milk varies ;
but it is almost impossible to count them. A conception of the fineness of
the state of division of the fat in milk is best obtained, so far as it is pos-
sible to measure it, by means of a simple calcujation, from Avhich we obtain
the following results, in the case of a sample of milk containing 4 per cent
of fat (taking the specific gravity of pure milk-fat as '924 at 17 "5° C): —

Diameter, in '01 mm. Diameter in '0016 mm.

The weight of a globule, - -000,000,483,8 rag. •000,000,002,0 nig.

The number of globules in 1

kilo, (approximately), - 80,000 millions, 20 billions.

The surface area of the glo-
bules in 1 kilo, of milk is
apjn-oximately, - - 25 square metres, 157 square metres.

If the diameter of the largest globule be 6 •25 times that of the smallest,
then its Aveight will be 244 times that of the smallest.

The impetus y and ^ which a globule receives through its weight and
centrifugal force may be stated as follows : —

y = a.g (J,- l) and ct> = a' (g,- l)- (^qJ')"'

in which a, and a', indicate the respective coefficients of resistance, S, and
^', the viscosity of the milk serum and milk fat, g the acceleration due to
specific gravity, and -n- the Ludolph number, r the radius vector, and u the
number indicating the circumference of the globule. The movement of
the fat globules in milk towards the cream layer in the ordinary rising of
cream, as also in the separation of cream by centrifugal force, is obvioiisly
not an accelerated one, but is uniform throughout. The other animal fats,
which, in addition to milk-fat, act as foods, are chiefly made up of stearin,
palmitin, and olein; Avhile milk-fat only contains, on an average, about 91
to 92 per cent of these neutral fats. The remaining 8 to 9 per cent prob-
ably consists of seven other neutral fats, among which butyrin and capronin
predominate Other five, viz. caprylin, caprinin, laurin, myristin, and butin,
a,re present in very minute quantities, some of them in the most minute
traces.

If pure butter-fat be saponified, and the butter so obtained be carefully
decomposed with sulphuric acid, as in the Hehner and Angell process, the
separation of the characteristic group of non-volatile and insoluble fatty
acids (stearic, palmitic, oleic, myristic, and butic acids), from the remaining
volatile and soluble fatty acids, can be easily effected, and their exact per-
centage determined. It is, however, impossible to estimate, even approxi-
mately, the percentage of the individual fats of either the non-volatile or

22 SCIENCE AND PRACTICE OF DAIRYING.

volatile groups. The individual members of both groups exhibit such
slight differences in their chemical behaviour and distinctive properties,
that as yet it has been found impossible to separate them from one another,
or to determine their composition. On this account the proportion of
stearin, palmitin, and olein in milk-fat, generally stated in the literature
of the subject, is practically unreliable. At the most, by determining the
so-called iodine coefficient of milk-fat, Avhich is proportional to the amount
of olein it contains, it can be ascertained which of two given samples of
milk-fat contains most olein. For the approximate determination of the
amount of the individual volatile fatty acids in milk -fat, Duclaux has
devised an ingenious method of determination. By this method the fatty
acids are reckoned as triglycerides, and the probable average composition
of milk-fat is calculated approximately as follows : — •

Palmitin, stearin, olein, and traces of myristin and butiii, 91 "50

Biityrin, 4-20

Capronin, ... ... ... ... ... ... ... 2*50

Caprylin, caprinin, and traces of laurin, ... ... ... TSO

lOO-OO

The percentage of insoluble and soluble fatty acids varies according to
the length of time after lactation, the amount of the soluble fatty acids
gradually diminishing, and that of the insoluble acids increasing, with the
increase of the duration of this period. To a certain extent the amount is
influenced by the individuality of the animal, and by the breed, probably
also by the age of the cow; but the influence of feeding has not yet been
proved with certainty. According to Adolf jNIayer the percentage of the
volatile fatty acids in milk-fat is distinctly increased by feeding with fresh
meadow hay, and is diminished by feeding Avith straw and poppy-cake.
The percentage of olein in milk-fat appears to increase with the lapse of
time after lactation. Butter-fat, containing a small percentage of volatile
fatty acids, contains, as a rule, a correspondingly larger percentage of non-
volatile fatty acids.

Lecithin, a suljstaiice containing nitrogen and phosphorus, may be
mentioned as a characteristic constituent of milk-fat. It is further to be
noticed with regard to the chemical composition of milk-fat, that it contains
less carbon than other kinds of fat. Milk-fat, freshly sepai'ated from cows'
milk, is, at ordinary temperatures, a soft yellowish mass, which soon
assumes a granular structure, and possesses a mild taste and very slight
odour. If melted butter-fat be allowed to cool gradually, it occasionally
occurs that a separation of the mass into two parts takes place, viz. a solid
portion, and a jjortion called butter-oil, which remains liquid at ordinary
temperatures. Milk-fat melts usually between 31° C. and 36° C. ; occasion-

MILK-FAT. 23

ally at not less than 41° C. to 42° C. In the case of most other fats the
melting-point is higher. The majority of the insoluble fatty acids which
make up milk-fat (palmitic, stearic, and oleic acids) melt at temperatures
between 38' C. and 39' C, or, according to Adolf Mayer's researches,
between 41° C. and 44° C, and become solid between 35° C. and 38° C.
The solidifying point of milk-fat lies, as a rule, between 19° C. and 24° C.
It may, however, vary between 27° C. and 12° C. At the moment of
solidification only a slight rise in temperature takes place, which proves
that the latent heat of milk-fat is very slight. The consistence and colour
of milk-fat depend on the influence of feeding, and vary according to the
lapse of time after the lactation period. They appear also to be dependent
on the age and individuality of the animal. The melting point of milk-fat
is said to be lowered by feeding with easily digestible carbohydrates, and
raised by feeding with fodders poor in sugar, such as sti-aw and oil-
cakes.

The specific gravity of milk-fat in air at 15° C. (distilled water taken at
the same temperature = 1) is, on an average, "930717; and in vacuum
(water taken at 4° C. as 1) it is, on an average, "93002. At the boiling
point of water, and at a barometric pressure of 760 mm., reduced to 0° C,
it varies between -8650 and -8685. Most of the other fats, at the boiling
point of water, possess a specific gravity of less than -8610. According to
M. Schrodt, the refraction exponent of milk-fat is only subject to small
variations, and is neither affected by the feeding of the cow, nor by the
lactation period, and is, at 22° C, on an average, 1'4590. With the
diminution of the percentage of the fatty acids it appears to increase. If
pure milk-fat be preserved from the action of air for some time, it becomes
rancid, that is, decomposition sets in, and small quantities of volatile fatty
acids, and particularly butyric acid, are set free. Free exposvire to air and
sunshine hastens the decomposition. Under such conditions volatile fatty
acids, directly derived from the glycerides of butter-fat, are also set free,
and other fatty acids, of which formic acid is probably one, are formed,
oxygen being absorbed from the air. Milk-fat, in this process of decom-
position, possesses not merely a rancid and strongly tallo'svish smell and
taste, but also assumes a white colour. Certain moulds, when the milk
becomes infected with them, produce decomposition, which is accompanied
by a gradual diminution of the volatile fatty acids of the milk-fat. In
this process butyrin shows itself to be less easily decomposed than capronin,
and the latter less easily decomposed than the neutral fats of the essential
fatty acids.

Although the hypothesis that the larger and the smaller of the fatty
globules of milk contain different kinds of fat, has not, so far, been con-
clusively proved, it has become more and more probable. The fat of the

24 SCIENCE AND PRACTICE OF DAIRYING.

larger globules appears to be finer in flavour, and to possess a more oily
appearance.

Bouchardat and Quevenne drew attention, as early as 1857, to the fact
that the average size of the fatty globules in human milk was different
from that found in the milk of cows or of sheep. It is probable that the
average size of the fatty globules of cows' milk, in the same cow, is not at
all times, and under all conditions, the same; and that in the case of
different cows, perhaps also in the case of different breeds of cows, even
under similar circumstances, the size varies. On this subject we know as
yet very little. The methods, according to which the numbers and the
determination of the average size of the fatty globules have been made,
are the same as have been applied for the purpose of counting the number
of yeast cells, blood corpuscles, &c., and consist of utilizing very fine capil-
lary tubes of glass.

Milk-fat is soluble in ethyl -ether, chloroform, carbon bisulphide,
benzine, &c. The common solvent is ethyl-ether.

7. Milk-sugar. — Milk-sugar occurs in solution in the milk of all
mammals, but does not elsewhere occur in nature. It is a carbo-
hydrate, and is one of the sugars capable of being converted directly
into alcohol by means of fermentation. In German milk the per-
centage of milk-sugar ranges between 3 and 6 per cent, and is on
an average 46 per cent.-'

In a state of solution, as it is in milk, the milk-sugar quickly
and easily undergoes decomposition, and is converted into lactic
acid. This is effected by a large number of different kinds of
bacteria, the so-called lactic bacteria. The transformation of milk-
sugar into lactic acid may, or may not, be accompanied by the
formation of small quantities of carbonic acid, with or without
alcohol. As the bacteria which give rise to the formation of lactic
acid are to be invariably found more or less abundantly on the
cow's udder or in the byre, in the dairies or in the vessels contain-
ing the milk, and have therefore easy access to the milk, it follows
that milk, on keeping, becomes sooner or later subject to lactic
fermentation. As soon as a sufficient quantity of lactic acid is
produced, milk sours and becomes unsuitable for its chief uses, both
in the house and the dairy. In milk which has become spontane-
ously sour, se\eral kinds of lactic bacteria may be identified. With
regard to one kind of bacteria, viz. the bacillus acidi lactici, I.

^ The same holds good for English milk. American milk ranges from 4 to 5 "5, with an
average of 4'95. (See Aikman's Milk: its Nature and Composition, p. 11.) — Engllsk Editors.

MILK-SUGAR. 25

Hueppe, Hueppe has shown that its development ceases below
temperatures of 10° C, is very feeble at 12° C, increases very
much above 15° C, and goes on briskly at temperatures between
35° C. and 42° C. When the temperature is raised above 42° C.
its development diminishes, until, at between 45'3° C. to 45"5° C, it
entirely ceases. Practical experience has shown that with regard
to other bacteria effecting lactic fermentation, rapid development
only begins at a temperature above 15° C. 15° C, therefore, may be
regarded as the temperature below which warm milk should be
cooled as quickly as possible if it is to be kept, and above which
cold milk should not be warmed if its keeping quality is not to be
impaired. The reason, therefore, why milk at 16° C. to 20° C. will
keep, even under the most favourable conditions, for only some 50
hours, and why it becomes necessary to have recourse to costly and
inconvenient preservative measures, is due almost entirely to the
milk-sugar present in the milk. In practice the only admissible
physical means for the prevention of premature souring in milk is
the cooling of the milk below 10° C, or heating it above 50° C. The
treatment of milk with chemicals (sodium carbonate, boracic acid,
salicylic acid, hydrogen peroxide, &c.) for effecting this purpose is
to be absolutely condemned.

Milk-sugar (laciine, lactose, C-^^H^i^u • HoO) was first discovered
as a constituent of milk in 1619 by Bartoletti. It crystallizes in deep
rhombic prisms, of a white transparent colour, and contains 5 per cent of
water of crystallization. It is comparatively hard, and is insoluble in
absolute alcohol and ether. It is soluble in 2|- parts of boiling water, and
6 parts of cold Avater. In concentrated solutions it presents a viscous
appearance, and exhibits a tendency to form supersaturated solutions. It
is only slightly sweet to the taste. Its specific gravity, compared with
water at 4° C, is l"5-45, and its elementary composition is as follows: —

Carbon, 40-00

Hydrogen, ... ... ... ... ... 641

Oxygen, 48-89

Water of crystallization. ... ... ... 5*00

100-00

Crystallized milk-sugar does not part with its water of crystallization
when heated to 100° C. On being heated for some time to a temperature
of from 100° to 130° C, it becomes slightly brown in parts, and begins to
decompose: a slight quantity of oxygen is absorbed, and a corresponding

26 SCIENCE AND PRACTICE OF DAIRYING.

amount of carbonic acid is given off. At 130° C. further decomposition
takes place, its water of crystallization is given off and galactose is formed.
This brown coloration becomes more pronounced as the temperature
rises. Lactocaramel, which is dark brown in colour, begins to be formed
at 175° C, and is accompanied by the development of a characteristic
smell. Grape-sugar is perhaps also formed. In milk this decomposition
begins when the temperature rises above 70° C, and is rendered apparent
by the slightly brown coloration (more or less pronounced according to
the length of time the milk is heated) which the milk assumes. Three
different forms of anhydrous milk-sugar are known. The optical behaviour
of solutions of milk-sugar under the polariscope is complicated, since they
exhibit bi-rotation and half rotation.

It is not as yet certain whether milk-sugar is I'endered anhydrous,
or retains part or the whole of its water of crystallization, when it is
heated in the process for the determination of its total solids; or whether,
indeed, under the varying circumstances under which such desiccation
may take place, it behaves always in the same manner. It would seem
probable that this is not the case, since, as is well known, the total solids
in milk do not admit of such accurate determination as is the case with
the milk-fat.

Solutions of milk-sugar, at ordinary temperatures, reduce alkaline
copper solutions. Treated with yeast or dilute sulphuric acid, galactose
and grape-sugar are formed. Galactose, an isomere of grape-sugar, and a
direct product of the fermentation of the sugars, can be obtained in small
Avhite plate-shaped crystals. If milk-sugar be warmed with nitric acid,
mucic and oxalic acids are formed, and also saccharic and tartaric acids.
With bases milk-sugar forms saccharates. Galactose yields, when boiled
with nitric acid, double the amount of mucous acid yielded by milk-
sugar when treated in the same way. When heated Avith hydrochloric
acid it yields Isevulin acid. When heated Avith chalk, milk-sugar
yields isosaccharine and metasaccharine. Although a molecule of milk-
sugar and a molecule of water contain the elements of four molecules of
lactic acid (Co Hg O3), in the case of ordinary lactic fermentation, decom-
position never takes place so completely and exactly that the milk-sugar
is entirely converted into lactic acid. Small quantities of a number of
other products in addition to lactic acid are formed, possibly from the
milk-sugar and possibly also from the nitrogenous matter of the milk.
The most extensive and thorough of recent researches on lactic fermenta-
tion have been carried out by Hueppe. His pupil Scholl has isolated and
given an exact description of ten different kinds of bacteria. The facul-
tative lactic bacteria are not of immediate importance since they are
rarely found in milk. The same applies to the few moulds (yeast) Avhich

THE INORGANIC CONSTITUENTS OF MILK, 27

have the power of converting milk-sugar into lactic acid and alcohol. By
the gradual formation of free lactic acid in the process of lactic fermenta-
tion, the lime and alkaline salts, present in milk possessing a faint alkaline
reaction, are gradually changed, and the amphoteric reaction of milk
disappears, and the acid reaction alone remains, and gradually increases in
strength. With the lapse of time this takes place to such an extent that,
although the milk remains liquid at ordinary temperatures, a slight
increase in temperature, or the introduction of carbonic acid, causes
coagulation of the milk. Finally, the casein, even at ordinary tempera-
tures, is decomposed from its combination with chalk, and is precipitated
in the form of a Avhite, cohesive gelatinous mass, which encloses all the
remaining constituents of the milk.

8. The Inorganic Constituents of Milk (Mineral, Incombustible, or
Ash Constituents). — The mineral salts of milk, as has already been
indicated, form a very important part of the milk, inasmuch as they
influence its properties considerably. When one carefully ignites a
portion of milk, a mineral residue is obtained possessing a weak
alkaline reaction, which, on treatment with strong acids effervesces,
and which, therefore, contains carbonic acid, but at the verj^ most
not more than 2 per cent. This residue varies in most cases
between "4 and "86 per cent, and constitutes on an average '75 per
cent of the milk. Closer examination will reveal, in addition to
small quantities of carbon, compounds of the metals potassium,
sodium, calcium, magnesium, and iron, in combination with chlorine,
phosphoric acid, sulphuric acid, and carbonic acid. If it be desired
to make a quantitative determination of the ash, and to ascertain in
what combinations the above metals are present in the milk, the
following considerations must be taken into account: —

(1) The carbonic acid present in the ash of the milk is formed, if
not entirely, yet largely, during the incineration of the organic
nitrogenous constituents. Carbonic acid is probably not present in
chemical combination in fresh milk, or if it be, it is certainly only
in such very small quantities that its efiect on the solubility of the
salts of milk is only of trifling importance. On this account it
requires no further consideration.

(2) For the same reasons the sulphuric acid may be excluded, as
it occurs, at most, only in traces, and is probably not found in milk
at all, and is a product of the combustion of the sulphurous nitro-
genous matter. As casein contains '85 per cent of phosphorus,
every 1 per cent of casein will yield, when burned, 0194 per cent

28 SCIENCE AND PRACTICE OF DAIRYING.

of phosphoric acid (Pg O^). Milk containing the average percentage
of ash, viz. "75 per cent, and the average percentage of casein, viz.
3-2 per cent, contains, therefore, in its ash, '062 per cent of phos-
phoric acid. Of this '062 per cent, about 8 per cent is derived from
the phosphorus in the casein. In order, therefore, to find the
quantity of phosphoric acid which is present as such in milk, 8 per
cent has to be deducted from that found in the ash, w^hich is, on an
average, 27*5 per cent of the total ash.

If this be done, and carbonic acid be deducted as well as the
sulphuric acid, and the small quantity of carbon present, the follow-
ing results, when the remaining portion is calculated to percentage
and the metals reckoned as oxides, are obtained, from which the
average percentage of the different mineral constituents of milk
may be seen: —

Potassium oxide.
Sodium oxide,
Calcium oxide,
Magnesium oxide,
Ferric oxide, ...
Phosphoric acid,
Chlorine,

25-64
12-45
24-58
3-09
34
21-24
16-34

103-68
Deduct oxygen for chlorine, ... ... 3-68

100-00

If we examine these figures more particularly, it will be found
that the chlorine (which without doubt is entirely combined Avith
the alkali metals) and the phosphoric acid, do not suffice to convert
the bases present into soluble salts possessing neutral or amphoteric
reaction, and that a large quantity of free calcium oxide remains
over. Even when we reckon that the casein, which plays the part
of an acid, forms a soluble compound with the lime, and that accord-
ing to Soldner this compound consists of 100 parts of casein and
1-55 parts of calcium oxide, there is yet an excess of the latter. Since
the carbonic acid which may be present in fresh milk in a state of
chemical combination is far short of being sufficient for effecting
neutralization, and since lactic acid is not present in fresh milk, it
necessarily follows that other acids — organic acids — are present in
the milk and conduce to bring about this amphoteric reaction.

THE OTHER CONSTITUENTS OF MILK. 29

Indeed, Henkel has proved that citric acid is a normal con-
stituent of milk. Whether, in addition to it, other organic acids not
yet discovered, may be present in milk, it is impossible to say. If
citric acid only is j^resent, milk must contain on an average some-
where about '25 per cent of it. Till now, perhaps in consequence
of the difficulty attending the exact quantitative determination,
only -1 to "15 per cent has been found. The following, according to
Soldner, are the probable combinations in which the mineral con-
stituents of milk are present (neglecting the small traces of iron): —

Sodium chloride, ... ... ... ... 10"62

Potassium chloride, ... ... ... ... 9"16

Monopotassium phosphate, ... ... ... 12"77

Dipotassium phosphate, ... ... ... 9 '22

Potassium citrate, ... ... ... ... 5*47

Dimagnesium phosphate, ... ... ... 3-71

Magnesium citrate, ... ... ... ... 4-05

Dicalcium phosphate, ... ... ... 7 '42

Tricalcium phosphate, ... ... ... 8 '90

Calcium citrate, ... ... ... ... 23'55

Calcium oxide in combination with casein, 5"13

100-00

In the above combinations of the mineral salts, if they could be
obtained unchanged, they would form 90 per cent of milk. Accord-
ing to Soldner's experiments, 36 to 56 per cent of the phosphoric
acid present in milk, and 53 to 72 per cent of the calcium oxide, are
not in solution, but are in a state of suspension in the form of
dicalcium and tricalcium phosphates.

To the above-mentioned constituents the following substances must
be added, as present in the ash of milk: silica, iodine (in districts near
the sea), calcium fluoride, and calcium carbonate. The chemical combina-
tions of the mineral salts of milk are not constant, but vary within certain
limits according to the state of health, the feeding, the period of lactation,
and perhaps also the age of the animal.

9. The Other Constituents of Milk. — In addition to the chief con-
stituents of milk enumerated and described above, several other
substances must be briefly referred to which, although occurring as
normal constituents, are always present only in very small quan-
tities, and partly in the gaseous form. These substances, therefore,

30 SCIENCE AND PRACTICE OF DAIRYING.

as a rule, are not taken into account in the quantitative analysis
of milk. Among these are nuclein and lecithin — substances which
have been already mentioned as constituents of the caseous matter
and of the fat of milk — urea, hypoxanthin, ammonia, citric acid,
cholesterin, sulphates, sulphocyanates, carbonic acid, oxygen and
nitrogen gas. Small quantities of substances derived from the food
of the cow, but which possess no nutritive properties, such as
colouring substances and odorous substances, are also found as
occasional constituents. Peptone does not belong to the normal
constituents of milk, and it is doubtful whether milk, in addition
to milk-sugar, contains any other carbohydrate of the dextrine class
in small quantity as has been asserted. F. J. Harz has recently
found in milk and in milk products such a body, and has named it
amyloid.

A peculiar interest attaches to the discovery of citric acid in cows'
milk, made by Henkel and confirmed by Anton Scheibe. It is found
also in goats' and in human milk. The percentage of citric acid in
cows' milk varies considerably. This variation, however, does not depend
on the feeding of the cow. On an average, it amounts to "1 to "15 per
cent of the milk. From the researches of Scheibe it appears that citric
acid is a specific constituent of milk, since, like the organic constituents of
milk, it is not originally present in the milk-glands in this form.

In condensed milk, viz. that condensed without the addition of sugar,
and in sterilized or preserved milk, concretions or bulky precipitates com-
monly occur, as Henkel has pointed out, which consist almost entirely of
pure calcium citrate.

Cows' milk contains only about -007 per cent of urea. Milk fresh
from the udder always contains a certain quantity of gases, oxygen,
nitrogen, and carbonic acid — the carbonic acid predominating. They may
amount to 6 per cent or more of the volume of the milk. S. M. Babcock
claims to have shown that milk contains yo^^oo of a per cent of fibrin;
but this requires further confirmation.

10. The Percentage Composition of Cows' Milk. — Very consider-
able variations are to be found both in the specific gravity and in the
composition of milk drawn even from the same cow at different times
(morning, mid-day, and evening). In the whole day's milk, yielded
by a single cow on the same day, the variations are within narrow
limits. This is still more the case where the samples are representa-
tive of a quantity of milk, drawn at the same time; and still more
to a quantity of day's-milk from a number of cows (more than five).

THE PERCENTAGE COMPOSITION OF COW S MILK.

The following figures are based on extensive experiments which
the author has carried out during a long period of years in different
places in Germany, as well as on other available German observa-
tions, and represent the average chemical composition of the day's
milk of large herds of cows (75 to 150), and the limits within which
the percentages of the separate constituents of such milk vary.

Average.

Limits of Variation.

Water,

87-75

87-5 to 89-5

Fat,

3-40

2-7 „ 4-3

Nitrogenous matter,

3-50

3-0 „ 4-0

Milk-sugar,

4-60

3-6 „ 5-5

Mineral matter ...

•75

•6 „ -9

100-00

The specific gravity of milk of this composition is 1"03165 at
15° C. The ratio of fat to nitrogenous substance is 100:103;
and the nutritive ratio 1 : 3-74. The composition of the total
solids is as follows: —

Fat,

Nitrogenous matter,
Milk-sugar, ...
Mineral matter,

27-75

28-57

37-56

6-12

100-00

Under ordinary conditions, the milk-sugar is the largest con-
stituent of the milk solids. The nitrogenous matter is slightly
in excess of the fat.

The average composition, according to the author's observations, of
the whole day's milk of comparatively large herds of cows in North
Germany, and of the countries bordering on the German Ocean, which
contain large-sized lowland cattle, is as folloAvs : —

Specific gravity, 1-0314 —

Water, 88-00

Fat,

Nitrogenous matter,
]\Iilk-sugar, ...
Mineral matter,

100-00

3-25

3-40

4-60

0-75

By the term " total solids " is understood all the constituents of

32 SCIENCE AND PRACTICE OF DAIRYING.

milk, except water. These amount, on an average, for Germany, in
the case of the day's milk of large herds, to 12-2.5 per cent.^ The per-
centage of fat may be stated at 27'75 of the total solids, and 3'4 per
cent of the whole milk, and the specific gravity at 15° C, at 1'334.
By deducting the percentage of fat from the total solids, the non-fatty
solids are obtained. These amount to 885 per cent of the whole milk,
and have a specific gravity, v/hich remains very constant, of 16.

The annual returns show that the specific gravity, for comparatively
large herds, if expressed in the form of degrees, ^ rarely rises or falls
more than 10 per cent, for milk of the different milking-times, taken for a
whole year. Similarly, the rise or fall of the percentage of fat rarely exceeds
30 per cent, of total solids 14 per cent, and of "solids not fat " 10 per cent.

The percentage of the several constituents in milk, obtained at different
milking-times, from compai'atively large herds, in the course of a year,
seldom falls below 2-4: per cent of fat, 10-5 per cent of total solids, 7-8 of
"solids not fat", and 1-028 specific gravity. The specific gravity of the
total solids rarely exceeds 1-37.

In the case of the milk of single milkings of single cows the limits
above stated are, of course, largely exceeded. It is almost unnecessary to
cite examples for the purpose of showing to Avhat extent this may take
place in certain cases. The milk of single cows, for example, as has been
observed by the author, may contain, when the cow is in heat, less than
1 per cent of fat, and shortly before becoming dry as much as 8 per cent.
The greatest variation among all the constituents is found in the milk-fat,
and the least in the " solids not fat ", and the specific gravity. For this
reason, in testing milk, for the purpose of foi-ming an opinion of its
quality, the determination of the specific gravity and of the "solids not
fat " are of especial value.

Few observations have been made with regard to the A^ariation in the
percentage of the nitrogenous matter and the milk-sugar.

11. The Relation between the Specific Gravity of Milk and its
Percentage of Fat and Total Solids. — That there is a relation between
the specific gravity of milk and its percentage of fat and solids is
clear; and it is obvious that these three factors are dependent on
one another. It is open to question whether the ratio betw^een these

^ The average percentage of total solids in English milk, according to Vieth, may be
taken at 12-90 per cent, and that of the fat at 4-1 per cent; while the total solids in American
milk may be taken at 13 per cent, and that of the fat at 4 per cent (Aikman's Milk: Its
Nature and Comiwdtion, Chapter II. A. & C. Black).

2 The thousandth part of the specific weight is called a degree. The specific weight
1"0332 expressed in degrees would therefore be 33 '2.

SPECIFIC GRAVITY AND PERCENTAGE OF SOLIDS. 33

three factors is the same for all kinds of milk, and whether it holds
universally true and is practically useful, and can be stated in a
definite form. If these three factors be respectively denoted by
the letters s, f, and t, the ascertained specific gravity of the milk-fat
by the letter cr, and the unknown specific gravity of the " solids not
fat" by the letter n, the value of s will be easily found by the
followinof formula: —

100 xnx (T

(1) s =

n X ff(100 -t)+nxf+ a{t -/) *

If n were like a- a constant quantity, equation (1) would give the
desired universally applicable ratio. Whether n is constant or not
can be easily discovered. It is only necessary to ascertain the values
of s, t, and / accuratelj^, for a large number of difierent milk samples,
in order to calculate the corresponding value of the letters in
equation (1).

(2)71 = 'Jll^rJA

100xff-sxo-(100-«)-sx/

If the above formula be worked out, the surprising result is
obtained that n is found to have always approximately the same
value. The author has obtained for a large number of determinations
in the North of Germany an average value for n of 1'60073-i.

From this it may be proved that the specific gi-avity of the
" solids not fat " is approximately a constant number, and that it is
possible, therefore, to write down equations for each of the above-
mentioned three factors, provided the other two are known.

If in equation (1) we take the value of 1"6 for n, and the known
value "93 for a , the following formulee are obtained: —

(3) <=l-2x/+2-665MxAzi00^
.s

(1)/= •S:33xi-2-22x^'^^^"-^Q'^,
a

and

ir. . 1000

, (O) .5 =

1000 -3-75(«- 1-2 x/)

The value of n is not, strictly speaking, constant, but is only approxi-
mately so. It varies within very narrow limits. In countries in which
the average composition of cows' milk materially difters from that found
in Germany, or in parts of Germany where the conditions are exceptional,
the average value for n may possibly vary to a small extent, but only so

far as to permit of the above equations (3) (4) and (5) always yielding
( M 175 ) "c

34 KCIENCE AND PRACTICE OF DAIRYING.

correct results, provided, of course, that the constant numbers which occur
in them are correspondingly changed. The author's practical experience
confirms in a very satisfactory manner the accuracy of the results deduced
from the formulae given above, especially (3) and (4), and it has been thus
shown that the constants of the formulae correspond very closely to the
conditions prevailing in Germany and England.

Should the numbers obtained in various places, however, despite
accurate calculation, not exactly correspond to those directly found, the
average value for n must be calculated from equation (2) and used in the
following equation : —

,^, , nxl-07527-1 ., n lOOxs-100

(6) t- ^ X/ + X .

71-1 n- 1 s

Taking n as equal to 1'6, and Avorking out the equation, formula (6) is
converted into formula (3).

By denoting the percentage of nitrogenous matter, milk-sugar, and
mineral matter in milk by x, y, and z respectively, and the respective
specific gravities by <r^, a.„ and a^, we obtain the following formula : —

„ 0-1 X 0-2 X (Tsix + y + z)

a; X (Ti X 0-3 + 2/ X (Ti X (73 + 3 X ffi X ff .,

As is easily shown, n is constant, either if ai^a-o-cro, or if the respective
ratio of :c, y, and ,~ be the same for all kinds of milk. Neither the former nor
the latter is exactly the case. Nevertheless the values of o-p o-.^, and 0-3
differ very little, as a close examination will show. The respective ratio
of .'?', y, and z is also not unknown. There is always more milk-sugar
than nitrogenous matter in ordinary milk; but the value of z in milk of
different origin only varies between "6 and '8 per cent. That the one
condition as well as the other is fulfilled, to a certain extent at any rate, is
obAdous, since through the combination of both of these favourable circum-
stances a very approximate constancy of value for n can be obtained.

The specific gravity m, of the total solids, is obtained from the equa-
tion—

sxt

[1] m--

sx«-(100xs-100)

For obtaining the value of t (equation 3), and m (equation 7), the
author has devised tables, by means of which the value of t can be obtained,
by a simple addition, and that of m through subtraction and division.

12. Colostrum (first milking, beastings, heistyn). — Colostrum,
which is the liquid secreted by the milk-glands both before and
immediately after calving, possesses peculiar chemical and physical

COLOSTRUM. 35

properties, and assumes gradually ^generally after the lapse of three
days from calving — the properties of ordinary milk. During the
first hours after calving it is always very rich in solids, and contains
large quantities of nitrogenous bodies, of which only about a half
are in a state of suspension. It contains only minute traces of milk-
sugar, sometimes none at all, but in its place small quantities of
other kinds of sugar. It has about the same quantity of, or even
less fat, than ordinary milk, and rather more mineral matter. It
possesses a yellowish or brownish colour, a peculiar smell, and a
slightly salt taste. Its reaction is generally slightly acid, and it
possesses a slimy, viscous appearance. It exhibits a variable re-
action towards rennet, and on being heated it coagulates. If kept
undisturbed, it often separates into two more or less distinct layers.
Its specific gravity at 15° C. varies between 1046 and 1079.
It is the most convenient and only natural kind of nourishment for
the young, and newly-born calves should on no account be deprived
of it, as it exercises an especial action on the intestinal canals, and
possesses also a high nutritive value. It is not suited for use in the
dairy. On this account the milk of cows, when they first begin to
give milk, is kept separate for four days if the milk be intended
for use in churning, or for ten or twelve days if it be intended to
use it for cream cheese.

The composition of colostrum changes quickly, hour after hour, from
the period of birth, until it assumes the properties and composition of
ordinary milk. Of an average composition, therefore, it is not possible to
speak. The following figures, however, may serve to give an indication
of its nature: —

Water,

787

per cent.

Fat,

4-0^

Nitrogenous (caseous) matter.

iu suspension,...

7-3

^ Total solid matter

Nitrogenous matter in solution, ...

7'5

2r3 per cent.

Sugar,

1-5

Mineral matter,

1-0 J

100-00

Especially characteristic of colostrum are certain grape-shaped bodies,
the corps gramdeuz, discovered in 1836 by Donne, the diameter of Avliich
lies between "005 and "025 mm. Henle has named these microscopic bodies,
which do not entirely disappear from cows' milk till three weeks after

SCIENCE AND PRACTICE OF DAIRYING.

calving, colostrum corpuscles (fig. 18). They are, despite a Avidely-spread
belief to the contrary, of no importance in the morphology of milk secre-
tion, and it is a mistake to look upon them as the type of the fatty
degeneration of the epithelial cells of the milk-gland basket.

According to Eugling, the colostrum of 22 Montavun cows, two to
thirteen years old, which had given birth to from 1 to 1 1 calves, possessed

Fig. 18.— Colostrum Cor-
puscles, (x 300.)

a, Cells showing fatty de-
generation; a', cells with
nucleus; b, cells contain-
ing large fatty globules;
c, cells with partially de-
stroyed membrane ; d, e,
cells which have com-
pletely lost their mem-
brane; /, Donn(5 corpus-
cles; g, h, group of cells.
(Furstenberg.)

a specific gravity of from 1"058 to 1"079
the following chemical composition : —

Average Composition

Water, 71-69

Fat, 3-37

Casern, 4-83

Albumin, 15-85

Sugar, 2-48

Mineral mattei-, ... r78

an average of 1-068, — and had

Limits of Variation

76-60

67-43

1-88

4-68

2-64

7-14

11-18

20-21

1-34

3-83

1-18

2-31

Total solids,

KKVdO
28-31%

23-40% 32-57%.

The ash of the colostrum, inclusive of phosphoric and sulphuric acid
formed by the burning of the j^rotein matter, had, on an average, the
folloAnng composition : —

Potassium oxide.

7-23

Sodium oxide,

5-72

Calcium oxide,

34-85

Magnesium oxide, ...

2-06

Iron sesquioxide,

0-52

Phosphoric anhydride,

41-43

Chlorine,

11-25

Sulphuric acid.

0-16

103-22

Dechict oxygen replaced by chlorine,

3-22

10000

THE SECRETION OF MILK IN THE UDDER. 37

Nuclein, lecithin, and cholesterin were found to be abundantly present
in the colostrum. The sugar found Avas not milk-sugar, but a sugar capable
of direct alcoholic fermentation; and the fat possessed a melting point of
between 40° and 44°, which is a very high melting point.

An analysis of ten samples of colostrum, made in the author's labora-
tory, showed in all cases comparatively large quantities of cholesterin and
lecithin. Leucin, tyrosin, urea, animal gum, and in some cases peptones
were also found. In the ether extract were found fat and small quan-
tities of free fatty acids and a yellow colouring matter. In addition to
milk-sugar, grape-sugar was found, and perhaps also some other kind of
sugar. Finally, the ash was found to be richer in the alkaline earths and
in phosphoric acid, and poorer in alkalies, than the ash of milk.

13. The Secretion of Milk in the Udder. — The physiological
forces at work in the milk-glands, during the period of lactation, are
dependent on the special surroundings of the individual animal and
on its condition. They give rise not merely to an active up-building
of tissue, but they also drive the secreted fluid into the cavities of
the glands and udder, and work without any external opposition
so long as the udder is not full. As soon as the cavity of the udder
is full, however, and when, owing to the continuous accumulation
of the quantity of the secretion, it begins to distend, there arises an
ever-increasing pressure against the sides of the secreting glands,
which most probably does not continue without a weakening reflex
action on the physiological forces above referred to. Perhaps this
explains the fact, found by experience, that the more frequently an
animal is milked in a day, it yields so much the more milk, contain-
ing a larger percentage of solids. It has also been found that the
quantity of milk obtained is in direct proportion to the percentage
of dry matter in the milk, but in inverse proportion to the length
of time between the successive milkings. The fact often observed
in practice, that milk, when yielded in large quantity, contains less,
and in small quantity more, dry substance, may be partly attributed
to the action and reaction of pressure. Generally, however, these
phenomena are due to other causes. The question as to whether
the milk lies in a ready-formed condition in the udder, or whether a
part is formed through the excitation of the nerves connected with
the milk-secreting organs during milking, in consequence of the
withdrawal of pressure in the udder, must be regarded as an open
one. The experiments made on this subject have given no decisive
results.

38 SCIENCE AND PRACTICE OF DAIRYING.

The space in the udder, which is occupied by the milk before
milking, consists of four milk cisterns, and of a richly-branched net-
work of canals and vessels leading up from them, the finest ends and
dilations of which form the gland-basket. When, after milking,
the udder begins to fill ao'ain, the milk formed must distend the
canals and vessels, where it is held by capillary attraction, and where
the forward movement of the fatty globules is retarded through
congestion and friction, before it reaches the milk receptacle. This
explains why it is that, under ordinary circumstances, the percent-
age composition of fat and of solids in milk steadily increases from
the beginning to the end of the process of milking, and its specific
gravity decreases; and why the milk which comes last is always
richer in fat. The increase of solids is sometimes as great, some-
times less, and sometimes somewhat greater than that of the fat: so
that we may well say it is practically influenced by the increase in
fat only. This phenomenon becomes more noticeable the longer the
time which intervenes between two consecutive milkings is. As a
rule, it may be said to take place no longer when the interval
between the milkings is less than four hours.

If a similar period intervene between the two milkings in the case of
cows milked twice a day, and the conditions influencing the health of the
cows are approximately similar, it may be said that between the morning
and evening milk, so far as quality and quantity are concerned, there is no
difference. If, on the other hand, the intervening periods between the
times of milking are unecjual, it may be almost always noted that the milk
obtained after the longer interval is greater in quantity, hut contains less
solids; and after the shorter interval is less in amount, but contains a
larger amount of solids.

After it had been discovered, as the result of experiments with a few
cows, and with shorter intervening periods, that milking three or four
times a day gave more milk, and milk richer in fat — occasionally with as
much as 20 per cent of an increase in amount, and as much as 25 per cent
increase of fat, — than is obtained Avith tAvo milkings, it was recommended
that cows should be milked regularly three times a day. The author will not
contend that, as a rule, milking three times a day, under otherwise similar
conditions, does not give a larger yield than milking twice a day; but he
is convinced, from numerous observations, that the amount of such increase
is largely exaggerated. In no case can it be expected in introducing the
two-times-a-day milking, instead of the three-times-a-day milking, or vice
versa, into large herds, that an increase or decrease in yield, similar to

LACTATION PERIODS. 39

that obtained in experiments carried out on a small scale, will take place.
Undoubtedly, in the case of single cows, the expansion of the milk cavity
in the udder, and the multitude of gland-baskets and their physiological
activity, accommodate themselves to the times of milking. According to
the degree in which this takes place, the differences, at first noticeable in
the yield, necessarily diminish, and it is highly probable that in most cases
they eventually entirely disappear. In large dairies, in the case of pastur-
ing animals, or where the milk is utilized in large factories, the three-
times-a-day milking system is practically inadmissible. If the system of
milking three times a day really gives an increase, which has not been
definitely proved, its adoption in small dairies may not always be found
to pay, when the increased expense, as well as the waste of time and the
inconvenience incidental to such a system, are taken into account. Of
course, in the case of heavy milking and newly-calved cows, the milking
must be done three times a day, or even oftener.

14. Lactation Periods. — The time during -which a cow gives a
continuous supply of milk, that is, the time intervening between
calving and becoming dry, is called the lactation period. This may
be taken, on an average, under ordinary circumstances, to be 300 days;
and the cows remain dry for the following six or eight weeks. In
most cases the milking capacity of the cow reaches its highest point
in the course of the first two months after calving, and diminishes
from then till the time when it becomes dry. The yield of the cow
may become reduced pretty gradually, or perhaps intermittently,
and in the latter case frequently occurs in three unequally long-
intervals, more or less distinctly marked. This natural process is
influenced by suitable treatment and management, and especially by
an intelligent regulation of the calving-time suitable to the local
conditions of feeding.

In the case of richly-fed and well-tended milk cows of average age,
the percentage of total solids in the milk almost always increases with the
advancement of the period of lactation. At the same time, not only is the
percentage of fat in the milk increased, but also the percentage of fat in
the dry total solids, so that the milk becomes absolutely, as Avell as rela-
tively, richer in fat. With regard to the behaviour of the other constituents
during lactation, Ave have up till now few reliable observations. G. Kiihn
found in the case of cows with which he experimented that generally the
percentage of protein, especially the caseous matter, increased Avith the
period of lactation, Avhile the albumin and the milk-sugar shoAved a
decrease.

40 SCIENCE AND PRACTICE OF DAIRYING.

15. The Age of Cows. — The milk-yielding capacity of good cows
increases, year by year, within certain limits, from the first lacta-
tion period, and from then decreases with increasing age. It may
be assumed that, generally speaking, the milk-yielding capacity of a
cow increases up to her eighth year. The age up to which it pays
to retain a cow differs in the case of individual animals and different
breeds, and depends also on the food and treatment of the animal.

In what way the chemical composition of the milk of single cows
varies from year to year with the increase of age has not so far been
closely investigated. According to experiments made in Kleinhof-Tapiau,
it would appear that in the case of cows which exhibited with increase of
age a decrease in their yearly yield of milk, it was found that the per-
centage of total solids decreased, and to a still greater degree that of the
fat. In these experiments the youngest cow yielded a milk containing
soHds richest in fat.

16. The Effect of Bulling. — The influence which bulling exerts
on the secretion of milk, during the period of lactation, varies very
much according to the individuality of the cow and her general
state. In many cows the bulling passes without a trace of effect,
and in others it has been noticed that the quantity of milk decreases
considerably, the specific gravity decreases, the percentage of fat is
largely reduced, often to 1 per cent, the milk becomes coagulated
on heating, and is not acted upon by rennet. These changes, how-
ever, even when they have been most marked, always disappear
quickly, usually entirely after two days.

It has been noticed that cows, Avhich during bulling yield a milk poor in
fat, directly afterwards yield a milk unusually rich in fat, so that, in this
way, the early decrease in fat is compensated for by the subsequent increase.
The earlier widespread opinion, that the spaying of cows always exercised
a favourable influence on the secretion of milk and on the capacity for
taking on fat, has proved itself unreliable. Careful investigations carried
out on this subject have shown that spaying, even in the case of selected
cows, is not to be recommended, if care be taken to render them valuable
by good feeding Avithout any operation. Spaying is only to be recom-
mended in the case of cows suffering from nymphemania (constantly in
heat).

17. The Working of Milk Cows. — In very many districts in some
countries milk cows are used for working purposes, and the result
is naturally enough a distinct decrease in their milk yield. The

FEEDING. 4 1

diminution in milk, however, is generally amply compensated for
by the work they effect, and there need be no fear, if working cows
are treated with care and intelligence, of their milk losing the
ordinary properties of milk. If, however, the cows be subjected to
too great a strain, the milk will assume abnormal properties, which
will seriously affect its value.

It may be well here to refer to the assertion recently made in America,
that the dishorning of cattle has a favourable influence on the yield of
milk. As, however, we have enough natural and approved methods of
raising the yield of milk in cows, Ave have no hesitation in condemn-
ing this barbarous and unfeeling custom, even supposing it actually does
exercise a favourable influence, which is very doubtful.^

18. Feeding. — It is almost impossible to make any generally
applicable remarks on the influence of food on the yield and
chemical composition of milk, since this varies, and is dependent on
the particular circumstances of the cows. There are cows whose
milk-glands possess such great activity that even with scant feeding
they give a large yield, which naturally is partly produced at the
expense of their tissue. Others, again, yield with rich feeding only
small quantities of milk, but become quickly fat; while, lastly, there
is another class, and these are the cows which ought to be reared
and kept as being best suited for dairying purposes, which yield,
with a continuous improvement in food, a steady, unfailing increase
in the yield of milk, until they reach, sooner or later, their natural
limits, or a limit which is determined by a consideration of the
net profits.

The best milk cows are those that are most affected by an
increase in the digestible constituents of food, and which respond to
that increase, in the most profitable manner, from the dairy point of
view. How far the treatment with food, in order to increase the
yield and profit, can be developed, has up to the present been but
little investigated. Perhaps the limits are less narrow than we are
just now inclined to assume, and it might be advisable to prove, by
means of experiments, whether it would not pay, in the case of well-

^ The i-eason assigned by Professor Fleisohmann appears to us inadequate. The extent to
which cows of some dairy breeds wound and gore each other with their horns is so great that
the practice of dishorning is really humane to the cattle, while it also removes a source of
danger to their attendants. The improvement in the milk production asserted to be noticed
in America as a result of the practice is no doubt due to the more peaceful life led by the
dishorned animals, and to their freedom from the wounds and injuries so frequently inflicted
by horns. — Editors of English Edition.

42 SCIENCE AND PRACTICE OF DAIRYING.

tended cows, to introduce feeding rations containing distinctly more
digestible nutrients than are at present usually regarded as most
favourable. Good milk cows, whose full capacity for giving milk
it is desired to develop, require, above all things, food which is not
only absolutely but also relatively rich in digestible protein, by
means of which the quantity of circulatory protein in the blood
may be increased. There can be no doubt that in the case of cows
yielding a large amount of milk, the fat derived from the food is
utilized for the formation of milk-fat. It seems advisable to the
author, therefore, that in the fodder of good milk cows, the per-
centage of digestible fat might likewise be somewhat increased over
what has, so far, been regarded as desirable. The old doctrine that
the composition of the solids of milk is little influenced by the
nature of the feeding; and that it is impossible to increase the per-
centage in milk, of any one constituent, by special feeding, has, up
to the present time, invariably proved itself correct. It has been
asserted, indeed, that an increase in the relative percentage of fat in
milk may be obtained by feeding with palm-nut meal and malt
combs, but this statement is based on isolated observations, and has
not been confirmed in dairy practice.

It cannot be regarded as correct that with increased percentage
of the dry substance of milk all the separate constituents are raised
in the same j)roportion. Nor is it true that the percentage composi-
tion of solids for one animal and one lactation period is approxi-
mately constant. It is similarly incorrect to suppose that with an
improvement in feeding an increase in the yield of milk is obtained,
which never aflects one or other of the separate constituents. This,
at any rate, does not hold good for the fat, since the percentage
quantity of fat is subject from day to day, and in the course of
a lactation period, to far greater variation than the other less vari-
able milk constituents. The percentage of fat in milk is without
doubt most sensitive to all the external influences that aflect the
yield of milk. Very often it is observed that the cow, when the
activity of the milk-glands is temporarily increased in course of
lactation, yields not only more milk, but a milk richer in fat, the
fat being increased more than the non-fatty solids. For example,
this is often seen at the beginning of pasturing in summer. Fur-
ther, accui-ate observations on the yield of milk from well-tended
and well-fed cows have sliown that the average composition of the
solids of the milk of single cows is generally proportional to the

Fat.

Total Solids.

Fat in
Total Solids.

3-226

11-913

27-08

3-242

11-953

27-13

4-518

13-948

32-39

4-908

14-596

33-62

FEEDING. 43

average percentage of fat, and that the animals yielding large
quantities of milk yield, in the ease of liberal feeding, a milk richer
in quality. It has also been found that animals "udiose milk is
absolutely richer in fat, at the same time yield milk relatively
richer in fat. As proof of this a few figures may be quoted, -which
the author selects from a number of available data:

(143j Dutch cows (Kleinhof-Tapiau)

(100) German cows (Raden)

(24) Short-horn cows (by Dr. Yieth)

(24) Jersey cows (by Dr. Yieth)

It may be observed, from the above figures, that the milk containing
an increased percentage of fat and solids is also always relatively
richer in fat.

From all this it would seem that the secretion of milk is to be
regarded as an organic process, which is more or less under the
influence and control of the formation of milk-fat. This has been
clearly demonstrated in the case of the secretion of milk by well-
treated and liberally-fed cows.

Hitherto it has been held that cows yielding a large quantity of
milk yielded a milk containing a small amount of solids. Assuming
that such cows do not receive food sufficient for develoj^ing to the
fullest extent their milk-forming capacity, this statement may be
regarded as generally correct. There are cows, however, which, if
richly and liberally fed, not only give a large jdeld of milk, but
also a milk with a high amount of total solids. That this is possible
is clear from the predominant action exerted on the percentage of
fat by all conditions that influence favourably the yield of milk, and
from the observation that the increase in the percentage of fat, if
not taking place at a similar ratio, j'et increases with the percentage
of non-fatty solids.

The most important quality in a milk cow is the capacity of
the milk-glands to yield, with certain feeding, the largest possible
quantity of milk of the best possible composition. The rearing of
breeds of milk cows possessing such properties has so far received
little consideration in Germany, yet the prospect of a great advance
in dairying is opened up by efforts in this direction, for all the
measures taken to increase the supply of milk, such as good feeding,
careful breeding, and other treatment, are almost certain to result in

44 SCIENCE AND PRACTICE OF DAIRYING.

a double reward, due to an increased yield of inilk, along with an
increased percentage of fat.

Tlie supplying of nourishment of a suitable kind and quality should
not be left to the promptings of nature or the caprice of the animal, but
should be regulated by regular laws, and varied according to the live
Aveight. For this reason, it has been agreed to regard as the standard of
comparison for the measurement of the food requirements of domestic
animals the weight of 1000 lbs. (in England and America), or 500 kilos
(in Germany). 1 Cows' milk, which is the natural food of young calves,
contains, as its nutrient ingredients, water, nitrogenous matter (protein),
fat, a carbohydrate, and mineral substances. These nutrients are the same
.as those on which the cow must be fed throughout her whole life, and
■which must be daily supplied in digestible forms and in definite quantities.
An average cow requires, according to the commonly accepted standards,
the following amounts per 1000 lbs. of live weight: — ■

Dry substance in food, 15 to 35 lbs.; average, 25 lbs.

Containing digestible protein, 2-25 to 2*75; average, 2*50 lbs.
,, „ fat, '4 to '6; average, "5 lbs.

„ „ carbohydrates, 10 to 15; average, 12-5 lbs.

,, dry substance in the form of coarse fodder 12 to 20;

average, 16 lbs.
,, salt (in addition), 10 to 70; average, 40 grams.

Cattle require daily, on an average, about three times more Avater than
■dry substance. AVith regard to mineral matters, it may be assumed that
these will be found in sufficient quantity in the daily food, if this be supplied
in sufficiency and of a suitable character.

The utility of a food depends on the ratio of the amount of nitrogenous
nutrients to the amount of fat and the other non-nitrogenous nutrients.
None of the different nutrients eifects a definite physiological action, but
each one has a particular function to perform in the animal system. The
nitrogenous matter of food has been named "flesh-forming", since its chief
function is to build up and renew the tissue of the animal body; while the
non- nitrogenous nutrients have been called "heat-giving", since they
chiefly effect the maintenance of heat in the system. As the nitrogenous
substance is indispensable for the formation and repair of the animal
tissue, and as this can be effected by no other group of nutrients, it
follows that the value of a feeding ration is, above all, dependent on its
percentage of protein matter. The ratio between the quantity of digestible
nitrogenous matter, and the quantity of digestible non-nitrogenous consti-
.tuents, in a ration, is expressed by a fraction Avhose numerator is 1. This

1 500 kilos := 1100 lbs.

FEEDING. 15-

is called the albuminoid ratio. The ratio of 1 : 5, which has been found
by experience to be suitable for the feeding of adult cows, may be con-
sidered as a standard ratio for purposes of comparison. According as-
the ratio is less or greater than 5, it is named a narrow or wide ratio. If
the ratio of nutrients is to be calculated, it is necessary, in the first place,
to reduce both the groups of non-nitrogenous nutrients, i.e. the fat and
the carbohydrates (digestible non-nitrogenous extract and digestible fibre)
to a common value. This is necessary in order that the quantity of fat
may be stated in its equivalent amount of carbohydrates. For this pur-
pose, the quantity of fat is multiplied by 2*5, which is called the starch
equivalent of fat, since it has been ascertained by experiments that by the
digestion of one part of fat (by weight) as much heat is jjroduced approxi-
mately as from the digestion of 2 '5 parts of cai'bohydrates. In order,
therefore, to find the nutritive ratio of a ration, it is necessary to multiply
the amount of digestible fat by its starch equivalent. This is added ta
the amount of digestible carbohydrates, and the total divided by the
amount of digestible nitrogenous substance. An example may serve to
make this clear.

A ration consisting of 8 lbs. of average clover, 10 lbs. of oat straw,
20 lbs. of roots, 6 lbs. of oats, 1 lb. of rape-cake, and 2 lbs. of earth-nut
cake from shelled nuts, has to be examined. From tables which will be
found in any text-book of agricultural chemistry,^ the following figures
may be found, which represent the average conmosition of the dry sub-
stance of the individual foods and their digestible nutrients.

8 lbs. clover hay, ...
10 lbs. oat straw,
20 lbs. roots,

6 lbs. oats, ...

1 lb. rajie cake,

2 lbs. eartli-nut cake,

Totals,

From the above we find that the ration contains 25 "65 lbs. of dry
matter, of Avhich 15"29 lbs. are in the form of coarse fodder. The follow-
ing quantities are the amounts of digestible constituents: — 2-51 lbs. of
nitrogenous matter, 8-77 4- 3"62 = 12"39 lbs. carbohydi'ates, and '67 lb. of
fat. The nutritive ratio is 1 : 5*6 for

67x2.5-H2-39

- = 5'6

Dry

Non-nitrogenous

substance.

Protein.

extract.

Fibre.

Fat.

lbs.

6-72

•56

2-02

•94

•10

8-57

•14

r67

2-34

•07

2-40

•22

1-82

•18

•02

5-26

•48

2-55

•13

•26

•90

•25

•23

•01

•08

1-80

•86

•48

•02

•14

25-65

2^51

8^77

3-62

•67

2-51

^See Johniston's Elements of Agricultural ChemUtnj, 17tli edition, revised by Dr. Aikman,
pp. 382-85 and p. 465 (Blackwood k Sons).

46 SCIENCE AND PRACTICE OF DAIRYING.

It should be noticed, however, that the digestibility of the nutrients
is by no means inconsiderably lessened by the addition of bulky fodder,
containing much non-nitrogenous substance, to a ration. It must not be
forgotten that such a lowering of digestibility would be exercised in the
case of the above ration by the 20 lbs. of turnips which it contains.

It is hardly necessary to say that putrefying food of any kind should
on no account be given to milk cows. Milk cows must also not be
fed with beans, peas, lupines, pea-straAv, or with large quantities of
barley-straw.^ The most suitable foods, and those which have the most
favourable action, besides good grass and hay, are the grain of cereals,
especially oats, and the different kinds of bran, especially coarse wheat
bran. All kinds of roots, including mangel and chopped turnips, may be
mixed with the eighth part of their weight of good cut straw, and potatoes
with about half their Aveight of straw. Approximately about eight
kilograms potatoes per day per 500 kilograms of live weight (17| lbs. to
1100 lbs.) may be recommended. If large quantities of potatoes ai^e used
in feeding it is best to steam them. Where the conditions of the farming
are such that very watery foods, such as distillery refuse and sliced roots,
have to be given, which are better adapted for fattening cattle than for
milk cows, care should be taken that the cows receive, if possible, at least
5 kilos, of coarse fodder daily per 500 kilos, of live weight (11 lbs.
per 1100 lbs.), and also ample quantities of digestible protein in their
total ration. Where roots are used, care should be taken to measure
exactly the quantities which are daily given. It is impossible, however, to
fix a precise limit to the quantity which it is advisable under all circum-
stances to allow. As soon as the rations are no longer eaten by the cows
Avith appetite, and the roots are no longer perfectly digested, both the
flavour of the milk and the milk-fat are in danger of being affected by the
root feeding. In the case of feeding Avith distillery refuse, the mangers,
which are apt to become contaminated with acid and fungoid ferments,
should be carefully kept clean, and, along with all places which come in
contact with the food, should be washed with freshly-prepared milk of
lime at least once a week.

The following conclusions drawn from practice are well worthy of
attention, even if they are not to be invariably relied on: —

Milk-fat becomes hard in its texture, in the case of feeding with peas,

1 In reply to an inquiry by the translators, Prof. Fleischmann writes that all the foods mentioned
can be successfully and properly used in feeding milk cows, provided they form a moderate proportion
only of a ration, otherwise suitable ; but that if used in excess they produce an unfavourable influence
on the milk products. Thus barley-straw has been found to influence quite perceptibly and unfavour-
ably the flavour of butter, and linseed-cake tends to produce a hard butter that has not the desired
texture. Experience in Germany has also gone to show that such foods as beans, peas, and lupines
can be moie freely and advantageously given to feeding cattle than to milk cows ; and that when
given to the latter, it should only be in moderate and suitable quai^tity.— Editors of Englinh Edition.

FEEDING. 47

vetches, rye, linseed -cake, cotton -seed cake, palm-cake, and palm -nut
meal.

The milk-fat becomes soft when rape-cake, oats, and Avheat bran are
used. Wheat, barley, and rye, earth-nut and cocoa cake, and malt combs
have no distinct influence on the texture of milk-fat.

When oil-cakes are used, it should be a rule that not more than
2^ lbs. at the very most of each kind of cake should be given per head of
cattle. The value of oil-cakes for rnilk-production may be placed in the
following decreasing order. The most useful is undoubtedly rape-cake,
then follow in the second place palm-cake and palm-nut cake, while cocoa,
earth-nut, and cotton-seed cakes, sunflower and hemp cakes, follow in the
third place. It is quite an erroneous belief to suppose that the cakes
mentioned in the third division exercise a generally detrimental effect on
the production of milk. This is by no means the case. These cakes
have a distinctly marked efficacy, as is also more especially the case with
rape-cake and palm-cake. If the milk-fat be hard and brittle, it can with
certainty be made soft and oily by using rape-cake, and by using palm-
cake, milk-fat which is soft and oily can be made to assume a firm con-
sistency. In winter rations, which consist largely of straw and potatoes,
a pound of rape-cake should never be omitted. According to the experi-
ments of Adolf Mayer, the melting point and also the firmness of butter
are dependent on the food, in so far that easily digestible carbohydrates
lower the melting point, while feeding with fodders poor in sugar raises it.

It is not advisable to feed milk cows with linseed-cake. Malt combs
must also be used with gi'cat caution, as under certain circumstances they
exercise a peculiar irritating eff'ect on the sexual organs.

In the production of excellent and good keeping butter, the best results may he
most certainly obtained by using, for the winter feeding of cows, good hay and oat
straw, with moderate quantities of beets or carrots, and ivith oats, tvheat bran,
and rape-cake.

Care should always be taken that the food supplied to cows is not only
nutritious and concentrated, but also palatable. In the rations pro-
vided, suitable quantities of salt should not be omitted, as well as pure
water of a proper temperature. The addition to the food of small
quantities of aromatic herbs may sometimes prove very useful. Alterations
in the mixture of the food rations are scarcely felt, if the composition of
the food, in digestible nutrients, is maintained at the same point, and if
the alterations be slowly and carefully effected. On the other hand, sudden
changes always produce distinct disturbances on the ^'ield of milk, a point
which may be specially shown by analysis of the milk. Changes in food
do not, however, produce a distinct effect in changing the milk from day
to day. The eff'ects are only clearly shown after the lapse of several days.

48 SGIENUE AND PRACTICE OF DAIRYING,

It is well known that milk may be watered through the animal body,
either intentionally or unintentionally. The more the custom of buying
milk according to composition prevails, the more rarely will this kind of
adulteration take place.

19. Milk Yields. — The amount of the average jaeld which the
different breeds of cows give in their own districts is of minor
interest. It is more instructive to inquire what is the average yearly
yield of a cow at present for the whole of Germany; and whether
this may be regarded as satisfactory. There are in Germany (and
in this matter we need not deceive ourselves) still large districts, in
which herds of cows, 20 and 30 in number, do not yield on an average
more than 2000 kilos. (4400 lbs.) of milk per amium. On the other
hand, there are isolated agricultural districts, in which herds of 80
and 100 yield, on an average, 4000 kilos. (8800 lbs.) of milk per
annum. There is no doubt that in Germany, on the whole, except-
ing in narrowly limited and advantageously situated districts, the
feeding of milk cows, both in quantity and composition of the
food, is not yet in proportion to their natural milk-yielding capa-
city. We are yet far from having reached the limit of the possible
economic development of the milk-yielding capacity of the cow.
Whether, under the present conditions of German dairying, we
have reached a yearly milk yield of 2500 kilos, per 500 kilos. (5500
lbs. per 1100 lbs.) of live weight, that is, five times the amount of
live weight, the author does not venture to decide; it is certain,
so far as his experience goes, that this yield has not been exceeded.
With regard to the endeavours which have been made to increase
the milk yield of our cows by intelligent breeding, much success,
on the whole, has not been attained. The solution of the much-
discussed question as to how to improve the quality of the milk,
up to the present time has hardly even been considered.

In the case of single cows, unusually large yields of milk have
been observed, amounting to 8000 kilos. (17,600 lbs.) per annum, or
36 kilos. (79 lbs.), and even more, per day. Cows giving the largest
quantity of milk, however, do not always give the most profitable
yield.

The relative moistness of the air, and the percentage of water in the food,
especially in the case of grass and the ordinary roots, which vary in the
different districts according to their geographical position, appear to
exercise, through their continued operation, a powerful influence on the

MILK-YIELDING CAPACITY OF COWS. 49

development of the milking capacity of cows, and mainly to fix the average
yearly yield of milk of the different groups of cattle in their native districts.
Those kinds of cattle which are recognized as the richest milkers, the black
and the gi'ay coloured Dutch breeds of the North German lowland cattle, as
■well as those breeds, the milk of which is characterized by its extraordinary
richness in fat, such as the Channel Islands breeds, the Jersey, the Guernsey,
and Alderney, have their homes in districts with a maritime climate of
the above-described nature.

Despite the commonly and emphatically expressed statement that
animals yielding a large supply of milk, always yield a milk with little fat
and solids, the question may be asked whether the animals and herds in
Avhich this fact has been noticed are always fed with a sufficiently rich and
nourishing diet — sufficient to enable them to attain to the limit of their
milking capacity. If this — and the author believes that those who have
large exi:)erience of practical dairying have not a doubt on the subject — is
not generally the case, we must freely admit that we know very little with
I'egard to the capacity of cows, yielding large quantities of milk, when they
are fed in such a way as to enable them to yield up to their full capacity.
There is no necessity, from a physiological point of view, for inferring that
a large milk capacity is necessarily always united with a low percentage of
fat and solids.

20, Milk-yielding Capacity of Cows. — A high milk-yielding capa-
city, i.e. the capacity to yield, within a certain time, a large quantity
of milk in proportion to live weight, and the secretion of a quantity
of milk greatly in excess of what is required for the sustenance of
the young, are independent of the form of the skeleton and the form
of the body of the mammal. Among the difierent kinds of ruminant
domestic animals, this capacity is most strongly developed in the
case of the goat, and least so in the case of the sheep. The power
of yielding large quantities of milk is not a natural characteristic of
the animals, but has been gradually developed in them, in the course
of time, through the influence of treatment by man. This property is
connected with hereditary qualities, but it is also, in a very variable
degree, an individual quality. Therefore, when special groups or
breeds of cattle are spoken of as being rich milkers, this denotes
nothing more than that it has been found by experience that rich
milking cows are more common in these breeds than in others. The
capacity, which has been artificially developed in a herd or breed, for
yielding a large quantity of milk, may be very quickly and very
largely lost again, if care be not continually taken to maintain the

( M 175 ) D

50 SCIENCE AND PRACTICE OF DAIRYING.

inherited property to its full extent. For this purpose a proper
selection of breeding animals must first be intelligently made, and a
careful superintendence of subsequent breeding, rearing, and suitable
feeding must be exercised, while attention, careful treatment, and
every other precaution must be exercised in regard to such circum-
stances as may exercise an influence on the milk yield.

A thoroughly reliable judgment on the value of a cow can only he
obtained from an exact record of her actual performances. Since, in the
case of calves and stirks, there can he no such record, and in the case of
cows which are for sale, till now, unfortunately, such records have only
been available in very iew cases, in order to obtain a standard for judging
this question, it is very common to have recourse to certain external
properties, such as the shape of body, &c., which stand in direct relation
to the usefulness of the cow, and give very probable indications with
regard to her value. Among external appearances which testify to high
milk-yielding capacity the following should be noted:—

(1) A very powerfully developed udder, which ought in no case to be
fleshy. A good milk udder is broad, and stretches back to the neighbour-
hood of the sexual organs, and in front to the neighbourhood of the navel ;
while on its lower surface it is well rounded and not pointed. The teats
should be set wide apart, and in the full udder should point outwards.
The so-called secondary teats should not be Avanting.

(2) A rich net-work of fine knotty veins, strongly developed milk veins,
and broad milk cavities, covering the entire udder, and showing distinctly
through its soft skin. The development of the whole system of milk
veins gives no reliable information as to the amount of blood circulating
in the udder, since a portion of the blood flows through the pubic vein
of the sexual organ, and there may also be found in fleshy udders highly
developed veins.

(3) In the perineum the occurrence of numerous narrow folds lying in
regular order beside each other, Avhich are especially well seen in an empty
udder, are soft to the touch, and are very loosely connected with Avhat lies
under them.

(4) A dusty secretion of fine, hairy scales, on rubbing the greasy skin
of the udder and of the perineum.

(5) Fine glossy hairs, fine thin horns, fine hoofs, a widely - spread
escutcheon, and a fine elastic skin. As these properties are dependent on
a strongly developed cutaneous gland system, one has a certain right to
infer from their presence a large development of the milk-glands, Avhich
are likewise included among the cutaneous glands. The milk-yielding
capacity of an animal is widely believed to be indicated by the condition

MILK-FAULTS. 51

of the hairs around the nose, the eyes, the ears, and the stomach, the
inside soft portions of the bone, the anus, the tail, and the hoofs.

(6) A general feminine appearance of the Avhole body. This is im-
portant, inasmuch as the activity of the milk-glands is intimately connected
Avith the discharge of the functions of the sexual organs of the female
animal.

(7) A fine head and tail, and fine limbs; in short, a fine bone system,
carrying a weighty body which has been built up by previous rich feeding.

(8) A barrel-shaped belly, deep, and the hind part of which should not
be tucked up, indicates the existence of good organs of digestion and the
capacity of making good use of food.

(9) A wide distance between the tuft of hair on the line of the back
and the edge of the frontal bone, wide interspaces between the spinous
process of the chest and the lumbar vertebrae, and a large space between
the ribs, as indications of a long chest and a lengthy body.

(10) A deep breast, as wide as possible, and a deep, broad pelvis.

The presence of the above characteristics may be taken as an indication
that the animal belongs to a carefully developed, good breed.

Although none of the above indications can be regarded as infallible,
all are worthy of careful attention. Bulls for breeding should be regarded
as specially valuable when they have had for their ancestors cows Avith
feminine qualities and good milk yields. Special care should be taken, in
the case of a bull, to have an animal Avith an equable temper and a body
free from defects. External signs of the latter are fine skin, glossy hair,
fine horns, Avidely-placed ribs, a broad posterior, and a Avell-formed escut-
cheon. Great stress is also laid on having the four rudimentary teats
of the scrotum Avell formed, and placed relatively in proper position.

21. Milk-faults. — Under the designation of milk-faults AA^ere for-
merly described the extraordinary beha\"iour shoAA'n by milk, Avhich
sometimes suddenly occurred from causes quite unknoAvn, and Avhich
seriously interfered with the dairy industry. When we read that,
in the period betAveen 1815 and 1830, in an agricultural district
of Mecklenburg, the disease of blueness in milk lasted for eight
years, and that in earlier times, in the best agricultural districts of
SchlesAvig-HoIstein, butter Avas unsaleable oAving to the fact that
the cream became cheesy in summer for months at a time, we realize
that the subject of milk-faults possesses the greatest practical interest.
It is of less practical importance at the present time, as such defects
seldom noAV occur. As the practice has extended of creaming milk
by centrifugal force, a practice which permits any quantity of milk
to be dealt Avith in a fcAV hours, and as the use of ice in the treatment

52 SCIENCE AND PKACTICE OF DAIRYING.

of milk has become common, and the necessity of taking suitable
precautions has become recognized, the more rarely have such milk
defects shown themselves. They still exist in various places in
small dairies, but in large dairies in which intelligent and clean
methods of working are followed, they no longer, and, indeed,
should no longer exist.

Although the changes which milk in certain cases undergoes
have not been fully elucidated, we know, nevertheless, that the causes
are for the most part not to be found, as was formerly surmised, in
the chemical condition of the food, the condition of the soil or
pasture-land, the illness of animals, &;c., but are to be sought for in
the activity of lowly organized forms of life. Only a few diseases
are traceable to other sources.

It was not uncommon in the past, for milk which had been standing
for about two days for the purpose of creaming, to become subject to putrid
fermentation, to curdle prematurely, to assume a bitter taste, to become
red or yellow in colour, sti'ingy, slimy, or soapy in texture; or for the
cream, after 24 hours' standing in the cream-vat, to become curdy, stringy,
and bitter in taste; or such difficulties might only show themselves in
the butter. Such undesirable phenomena rarely occur now in the larger
dairies, and if so, only in the case of the cream. Should they threaten to
manifest themselves, it is now easy to combat them if the desire and
requisite knowledge are possessed by the dairyman.

With regard to changes commonly occurring in milk or cream, which
are not caused by ferments, the following may be mentioned : — •

Milk in which Cream Bises Slowly {Lazy or Dead Milk). — This fault
is only found to any extent when milk is treated with ice. It manifests
itself in a striking diminution of the yield of butter under ordinary
treatment, even when there is an equal, perhaps even an increased,
percentage of fat in the milk. In order to prevent its development the
milk should be creamed by centrifugal force, or by the Holstein process,
or should be churned as whole milk. The milk of cows which have been
long milked is often subject to this unwelcome fault. It not merely occurs
in autumn, as has been asserted, when the cows are for the most part
becoming dry, but also in the spring, shortly before they receive green
food, or are turned out to pasture. Undoubtedly it arises from the fact
that the original condition of the nitrogenous matter of the milk becomes
changed in an abnormal manner, so that a large portion of the fatty
globules experiences an opposition which prevents them from rising freely.
It has been noticed that milk which exhibits a difficulty in creaming con-
tains less calcium phosphate than ordinary milk.

goats' milk. 53

Milk Difficult to Churn. — The cause of this fault, Avhich greatly
impedes the churning of milk or cream, and which, indeed, can even make
it impossible, may be traced for the most part to gross violation of the
rules of dairy management. Occasionally, perhaps, bacteria may also be
implicated. When it shows itself in milk from old milking cows, churn-
ing is often rendered possible by raising the temperature, under certain
circumstances, up to 25° C. Again, cream sometimes becomes excessively
soured, and hence is difficult to work. It may be made suitable for
butter-making by treating it with a soda solution (200 grams to 1 litre of
water), so as to make it very slightly alkaline, and then again very
cautiously making it slightly acid with hydrochloric acid (12 c.c. of the
commercial acid to 1 litre of water).

Saiuly Milk. — This fault, it Avould seem, is essentially caused by the
peculiar condition of the food, or by disease of the cow. It arises from
the fact that, inside the vessels and canals and milk-cisterns of the udder,
phosphate of lime is separated out in fine ciystals, and causes the stop-
page of the milk-tracts of the teats. Inflammation of the udder arises,
accompanied by the formation of milk stones and concretionary nodules
in the udder.

Further remarks on the subject of milk-faults will be found in
Chapter III., where the micro-organisms and their influence on
dairying and dairy products are treated.

As an appendix to Chapter I., some remarks on the properties
of goats', sheep's, and mares' milk may properly find space here.

22. Goats' Milk. — In Germany, the milk of goats, with the
exception of a very small proportion, which is used in the manufac-
ture of cheese, is directly consumed, and is used in the small dairying
districts as a substitute for cows' milk. As it is admirably suited
for this purpose, it appears desirable that as large an increase as
possible in the use of goats' milk should take place, and this all the
more because tuberculosis, a disease which is very widely spread
among so many breeds of cows, and which is comnumicable to man-
kind, is unknown in goats. Goats' milk has a white colour, very
often a slight yellowish tinge, a weak characteristic smell and
flavour, and a slightly slimy consistency. On an average, it is
richer in solids, especially in soluble nitrogenous substance (albu-
min), than cows' milk, and is less easily creamed. It would appear
that the fatty globules are, on an average, somewhat smaller than
those in cows' milk. The smell of the he-goat, which is common
in goats' milk, is not a characteristic of the milk itself, but is

SCIENCE AND PRACTICE OF DAIRYING.

peculiar to the skin of the goat (fig. 19), and is imparted to the
milk externally.

In the year 1883, 2,600,000 goats were kept in Germany, that is to
say, they numbered 5-8 for every 100 inhabitants. Between the years
1873 and 1883 the number of goats kept increased by 13-8 per cent. It
is a well-known fact that goats are characterized by a high milk yield.
If we take the live Aveight of a goat at 30 kilos. (66 lbs.), and the annual
yield of milk at only 300 kilos. (660 lbs.), it will appear that goats yield in

Fig. 1!>.— Pyienean Milking Goat.

milk ten times their live weight. Animals Avith large milk-yielding capa-
cities can, if well fed, yield annually 800 kilos. (1760 lbs.), or even more.
Goats carry their young, on an average, about 154 days, and the lactation
period is four to five months. The time of their milk-yielding period
in the year is generally about six months, less frequently four months,
and on occasion it may extend to ten months. So far as investigations

have shown, goats' milk on an av

Water,

Fat,

Caseous mattei-,
Albumin,
Milk-sugar, ...
Mineral matter,

Total solids,

erage has the following composition : —

8o-5

4-8

3-8

1-2

4-0

100-00

14-5%

SHEEP S MILK.

The specific gravity varies between 1"0267 and 1-0380, and may be taken
on an average as 1-033, at 15° C. In § 9 it has already been noted that
goats' milk, like cows' milk, always contains citric acid.

23. Sheep's Milk.— On many of the larger estates of North Ger-
many, every year in July, after the lambs have been weaned, the
ewes (fig. 20) are milked for a short time, but, as a rule, for not more
than fourteen daj^s. The milk obtained is made into cream. It

Fig. 20.— Friesian Milking Sheep.

possesses a white yellowish colour-, and a characteristic weak, and
not very pleasant, smell and taste. It is richer in solids than cows'
milk, sours more slowly, and requires for coagulation more rennet
than either cows' or goats' milk. It creams with difficultj^ and
yields a soft oily butter, not suitable for keeping, and possessing
an unpleasant flavour. The fatty globules are, as a rule, larger than
those either of cows' or o-oats' milk.

In the year 1883 there were over 19,000,000 sheep in Germany, which
gave, on an average, 42 to every 100 inhabitants. From 1873 to 1883
the number decreased, owing to causes which are well known, and need not
be referred to here, by 23-3 per cent. Although it has been affirmed that
milk sheep can give a large supply of milk, up to 700 kilos. (1540 lbs.)

SCIENCE AND PRACTICE OF DAIRYING.

yearly, the amount that is obtained, on an average, is only about 50 to
70 kilos. (110 to 154 lbs.). If the average weight of a sheep be taken at
40 kilos. (88 lbs.), and the yield of milk annually at 60 kilos. (132 lbs.),
the sheep may be said to give a half more milk than its live weight.
Sheep carry their young, on an average, 154 days. The lactation period
may last about four months, and the time during which the sheep yields
milk from four to six months in the year. Examination has shown that
sheep's milk is, on an average, of the following composition : —

Water,

Fat,

Caseous matter,
Albumin,
Milk-sugar, ...
Mineral matter.

Total solids,

83-0
5-3
4-6
17
4-6
•8

100-00
17-00%

The specific gravity of sheep's milk probably lies between 1*035 and
1-041 at 15° C. The tables, which are suitable for reducing the specific
gravity of cows' milk at any temperature to 15° C, are not available in the
case of sheep's milk. The results of seven years' consecutive examination
of sheep's milk of old milking (of the Boldebucker) breed, at Eaden. by
the author, gave an average specific gravity of r0369 at a temperature
between 12° and 18' C The average composition Avas as follows: —

Water,

Fat,

Caseous matter.

Albumin, ...

Milk-siigai',

Mineral matter,

Total solids.

75-400
11-773
6-475
1-639
3-651
1-062

100-000
24-600%

It is well known that the most celebrated of French cheeses — the Roque-
fort— is made from sheep's milk.

24. Mares' Milk and BuflFalo Milk. — Mares' milk has been made
the subject of searching investigations, because some nomadic
horse-rearing tribes inhabiting the steppes of the south of Russia
and the interior of Asia prepare Koumiss from it — a beverage
■which has been thought to have a good effect in certain diseases.
In Germany, mares' milk is never obtained or- used, l)ecause Koumiss,

mares' milk and buffalo milk. 57

whenever wanted, can be made out of the skimmed milk of cows.
Mares' milk is characterized by a comparatively small percentage of
total solids, and an exceptional richness in milk-sugar. It possesses
a watery appearance, a white or bluish colour, and a sweet taste.

Mares yiekl milk, on an average, for 340 days. The mares of Tartary
are said to remain occasionally in milk for two years, and to yield 200 to
225 kilos. (440 to 495 lbs.) of milk annually, exclusive of the milk con-
sumed by the foal. According to researches, the composition of mares'
milk is as f oIIoavs : —

Average. Variations.

Water, 907 92-53 to 89-05

Fat, 1-2 -12 „ 2-45

Nitrogenous matter, ... 2"0 1'33 „ 3-00

Milk-sugar, 5-7 4-20 „ 7-26

Mineral luatter, '4 '28 „ 1*20

100-00

Total solids, 9-3%

The specific gravity is practically the same as cows' milk.

Buffalo milk is not known in German dairying. In the districts
in which tame buffaloes are kept, their milk is highly prized, on
account of its richness in fat and its pleasant flavour. It has,
however, been very slightly investigated. In colour it is slightly
yellowish.

The milk-yielding period of the buffalo lasts probably for ten months,
in some cases even to eleven or twelve. During a year, buffalo coavs may
yield, on an average, someAvhere about 800 kilos. — indeed, if carefully
treated and well fed, the yield of milk may amount to 1500 kilos. (1760 to
3300 lbs.) and even more.

Two samples of buffalo milk investigated by the author, one of which
came from Transylvania and another from Koumania, had, on an average,
the following composition : —

Water,

. 82-93

Fat,

7-46

Nitrogenous matter,

4-59

Milk-sugar,

4-21

Mineral matter,

•81

100-00

Total solids, 17-07%

The Roumanian sample had a specific gravity of 1-0339 at 15° C.

CHAPTER 11.

THE EXTRACTION, IMMEDIATE SALE, AND THE TESTING OF MILK.

25. Milking. — It is of the greatest importance, for the purposes
of improving- the milking capacity of a cow, and obtaining the
largest possible quantity of fat, that the operation of milking should
always be carried out in a proj)er manner. The milk last yielded,
as has already been mentioned in § 13, is always the richest in
fat. In milking, the udder should be perfectly emptied at each
milking; and the cows should, above all things, be treated with
the indulgence, quietness, and gentle handling required by their
nature. Furthermore, the same person should not attempt to
milk more cows than he is able to accomplish properly; and the
individual cow, during the period of lactation, should, if possible,
be milked always by the same person. It is only when milking is
carried out by intelligent, careful people, and the cow is hand-milked,
that the usefulness of milk cows can with certainty be developed
and maintained, and it is only those who are entirely ignorant of
the nature of the milking operation who can abandon themselves
to the idea of using milking machines of any description — for
example, milk tubes.^ The use of milk tubes is only permissible in
the case of disease of the udder of the cow. Milking should be
done either with the whole hand, or, as is customary in the hilly
districts of South Germany, only with the first and middle finger,
with the assistance of the bent thumb. On no account must it be
omitted to press the udder gently and repeatedly between the
hands, not merely at the beginning of milking, but also during the
process of milking. The custom prevalent in these hilly districts
exercises a greater strain, but is far cleaner than milking with the
whole hand, since by the latter method it is almost impossible to
avoid bringing the milk into contact with the palm of the hand,
which is often very dirty. It is hardly necessary to say that the
hands of a milker should be washed before milking, and whenever
necessary, the udder and the teats should be carefully cleansed.

^ When this sentence was written by Prof. Fleischmann, the Thistle Milking Machine
had not been invented. — Editors of Enc/lish Edition.

rv' ^ rri.

MILKING.

Nevertheless, cleanliness in the byre is still believed to be neglected
in most of the larger agricultural districts of Germany, more espe-
cially in North Germany. Very much can be done, by means of the
greatest possible cleanliness in milking, to improve the keeping
quality of milk, and to give uniformity to the manufacture of the
dairy products. Milk which has been handled without the due
observance of cleanli-
ness, especially milk
which has been con-
taminated with cow-
dung, or with the dusty
particles of hay, is
very difficult to ster-
ilize. On the other
hand, the sterilization
of milk which has been
handled in a cleanly
manner is compara-
tively easy to effect.
The milk which first
comes from the teats
should be put aside,
and not mixed in the
milk -pails with the
rest of the milk; and
in milking (fig. 21) old
cows which have been
giving milk for some
time, a sample of the milk from each teat should be tasted, in order
if necessary to put aside the whole milk of the cow.

In every well-regulated dairy, samples should be taken regularly
in order to ascertain the record of each cow. It is advisable in this
operation to weigh the milk rather than to measure it, and to test
the milk in all circumstances at least once a week.

Fig. 21— Position of Hands in Milking. (From Grotenfelt's
Principles of Modern Dairy Practice.)

In the hilly districts of South Germany milking is done by men, but in
North Germany it is generally done by women. When the cows are rest-
less or hold back their milk, the cause always lies in a disordered condition
of the udder, whether due to accumulation of blood in the veins, as is
believed by Fiirstenberg, or to its accumulation in the arteries of the

60 SCIENCE AND PRACTICE OF DAIRYING.

udder, as is believed by Von Rueff. Force in such a case Avill never help
matters. Many cows have warts on the teats, Avhich increase the difficulty
of milking. It is asserted that when the warts are injured, the blood
flowing from them may cause formation of new warts where the blood falls
and dries.

26. Treatment of Milk after Milking. — After milking, everything
depends on treating the fresh milk in such a way that it may
undergo the least possible change before it is used or manufactured.
For this purpose care ought to be taken to provide the conditions
most favourable for its keeping. The milk should be removed as
quickly as possible from the byre, and from any buildings in im-
mediate communication with it, and should be placed in a room
with pure fresh air. If it is not to be immediately used, it should
be at once strained and cooled quickly to at least 12° C. The lower
the temperature to which it is cooled and kept at, the better will it
keep. If there be no ice to effect this, the keeping power of the
milk may be improved by Pasteurizing, a process well suited for
milk designed for consumption, which has to be kept for some time
before it is used. It cannot be doubted, however, that the spontan-
eous coagulation of milk is delayed by Pasteurizing, and at ordinary
temperatures, only takes place, on an average, twenty-four hours
later than in the same milk which has not been Pasteurized, but
which has been otherwise subjected to the same treatment. More-
over, the practical carrying out of this process may be regarded
as very unreliable. Especialh^ is this the case if the hot milk,
when removed from the Pasteurizing apparatus, to be cooled down
to the necessary temperature of at least 12° C, comes into contact
with air heavily laden Avith spores of ferments.

The addition of chemicals, so-called " preservatives " to milk,
such as bi-carbonate of soda, boracic acid, salicylic acid, peroxide of
hydrogen, &c., is, under all circumstances, to be emphatically con-
demned on principle. The tAvo first-named preservatives act only
temporarily, by neutralizing the free acid present in the milk, and
by dissolving some of the coagulated caseous matter, but instead of
arresting the lactic fermentation, they actually help it. The other
preservatives exert an antiseptic property.

In various places the creaming of milk by means of the centrifugal
separator, and also the cooling of Avarm milk fresh from the cow, is allowed
to take place in the byre itself, or in some room in immediate connection

THE DISTRIBUTION OF MILK.

with the byre. It is unnecessary to say that such a practice is totall}^
against all rules of proper dairying.

By the Pasteurizing of milk is understood a process of heating the milk,
for a short time, under the boiling point of water (between 56° and 80° C).
Milk is usually Pasteurized by placing it in the inside of a Pasteurizing
apparatus, and then heating up to 70° or 80" C, and subsequently cooling
to 12° C. It has been proved by experiment that the bacilli eft'ecting lactic
fermentation are, for the most part, destroyed by a momentaiy exposure
of the milk to a temperature
of about 80° C, and the vita-
lity of the remaining bacilli,
along with the rest of the
lower micro-organisms present
in the milk, is so impaired
that their action is temporarily
stopped, and their develop-
ment checked for a time. If
this process be carefully car-
ried out. Pasteurized milk
does not exhibit, or exhibits
only to a very slight extent,
that peculiar unpleasant taste
possessed by boiled milk,
Avhich is so disagreeable to
many people. We shall have
something to say in a sul>se-
quent chapter on the Pasteur-
izing of milk.

For the purpose of eft'ecting the rapid cooling of milk for general use,
the milk-cooler or refrigerator (fig. 22) constructed on the plan designed
by Lawrence is thoroughly to be recommended. It is able to treat per-
fectly from 200 to 1200 litres (44 to 263 gallons), of milk in an hour.

It is believed in America that milk should be aired by means of special
apparatus, in order to free it from the so-called animal smell. In Europe
this custom is not general, and in Germany it is regarded as useless and
unnecessary. ^

27. The Distribution of Milk. — In the moviug about of milk, it
is necessary to protect it from rapid fermentation, violent shaking,
contamination, or adulteration. Milk in its warm condition may
only be moved short distances, such as, for example, from the byre

1 This apparatus has been employed in some cases in Britain with advantage. — Editors of
English Edition.

Fig. 22. — Lawrence Refrii^erator.

SCIENCE AND PRACTICE OF DAIRYING.

to the dairy, and then it should only be in open or loosely-covered
vessels, in order that it may become cooled by the cooler air, and
that evaporation may take place from it without hindrance. When
carried further, milk must first be cooled to 12° C, and tightly closed
vessels must be used. Care must also be taken that the cooled milk
does not attain on the way a temperature at which rapid fermen-
tation may take place. If wooden vessels be used, this is not
difficult to effect, since wood is a bad conductor of heat. It is more
difficult to accomplish when metal vessels are used, which is neces-
sary when milk is sent longer distances by rail.

In order to avoid, as far as possible, the
formation of lumps of butter in the milk,
through violent shaking, a light waggon is used
for the conveyance of the milk, and the barrels
are filled full, or if not full, carefully cleaned
wooden floats are used. For the purpose of
distributing the milk from one place to another
in the country, large wooden vats are best,
Avith wide openings and suitable floats. Such
vats are not so quickly or so easily cleaned as
metal vessels, but in other respects are pre-
ferable, inasmuch as they preserve the milk
excellentl}'^ from the action of external warmth,
and they also last longer and are cheaper. For
all other purposes, especially for the distribu-
tion of milk by rail, metal cans are most suitable,
and they are easier to handle (figs. 23-25).
Very useful and suitable are the conical cans,
holding 36 to 77 litres (8 to 17 gallons), made
of steel plates, which are used in England, although, unfortunately, they
are still unknown in Germany. In Germany only cans made of Avhite
metal are used, which contain, for the most part, only 20 to 25 litres (4i to
5 gallons).

28. Value of Milk for Fattening Purposes. — The use of milk for the
fattening of swine is not economical, and ought only to be adopted in
rare cases. On the other hand, the fattening of calves with milk is
much practiced, and under favourable circumstances is attended by
verj' good results. The treatment of fattening calves in feeding
requires great attention and care, as well as skill of a special kind,
which everj'one does not possess. For obvious reasons, this practice

Fig. 23.-Kail\va.v ililk Can.

THE VALUE OF MILK AS AN ARTICLE OF SALE.

more generally prevails, and gives better results, on the smaller than
on the larger farms. If, as is commonly the case, the fattening process
last from eight to twelve weeks, it may be assumed that on an
average 10 kilos. (22 lbs.) of milk make 1 kilo. (2-2 lbs.) of live
weight. The value of the kilo, of milk must be considered with
reference to the price of veal. It is well known that the flesh of
calves which have been exclusively fed on fresh milk is of excellent
quality, and possesses the desired yellow colour of good meat.

The fattening of swine with milk was formerly very common in some
districts of the Archduchy of Oklenburg, but is now almost entirely

Fig. 25.— Cart Milk Can.

Fig. 24. —Top of Milk Can, with Seal and Pinters,
showing Mode of Fastening.

abandoned. In the case of fattening calves it is impossible to give any
definite figures of the daily amount of milk to be used. As much should
be given daily as the calves care to drink, but great care should be exer-
cised against over-feeding, and against allowing them to drink too quickly.
A drink three times a day at least, with milk of a suitable temperature,
is necessaiy. It is also necessary to keep the calves in separate boxes, in
narrow byres, shaded from light, in order that they may remain as quiet as
possible. The byres should always be kept clean.

29. The Value of Milk as an Article of Sale. — It is often the case
that milk is not treated on the spot where it is produced, but is sold.

Qi SCIENCE AND PRACTICE OF DAIRYING.

Before determining to sell milk, the question should be considered
whether this method of utilizing it is really the most remunerative.
A very simple calculation in each case will enable this question to
be easily answered. A few remarks will be made on this subject
in Chapter VII.

The most profitable way of disposing of milk is to the private
consumer, since the price of milk in all the larger towns is almost
alwaj^s at a figure which can very rarely be obtained, and that only
under the most favourable circumstances, when milk is churned or
otherwise disposed of. The practice least to be recommended, as a
rule, is that of selling the milk to small milkmen, because this
method is often very inconvenient and troublesome. In order to
avoid this difiiculty, farmers in recent times have founded many
associations for the purpose of calling into existence town dairies,
which may effect the sale of milk, and in which whatever milk
remains over unsold is daily worked up or churned. Such arrange-
ments have worked very well. Through the development which
has followed the extension of railways, agriculturists who live less
than twenty miles distant from a town, and not too far from a
railway-station, may become members of a town company, or
partners in a town dairy business. In all cases in which the sale
of milk is either exclusively or chieflj^ made for direct consumpt,
the seller may be regarded as silently assuming the moral obligation
to make every effort to su23ply all his milk unadulterated and as
rich as possible.

The proper arrangements for the supplying of towns with milk,
carried out in the shops of milk merchants in large milk businesses in
towns, and in shops for the sale of specially prepared milk for
children and invalids, can scarcely be regarded as coming within the
scope of purely agricultural industries, and therefore need not be
described here. The author contents himself with a few remarks
reoarding them.

If milk in the milk-market, which comes from small milk merchants in
the towns, or from milk producers direct to the consumers, suffers in the
matter of cleanliness or percentage of fat and total solids, the blame is
undoubtedly with the small dealers or Avith the milk producer. No doubt
they should not alone bear the blame of the matter, for the blame must
also be shared by the great public, Avhich patiently allows itself to be
imposed on.

It is in the interests of the public good to limit as much as possible

MILK ADULTERATION. 65

retail business, and in a suitable way to effect a concentration of the
business of milk selling.

Every large town milk business should be conducted in the same way
as every large town milk association. On the one hand, the milk suppliers
should be boimd to pay attention to the cleanly treatment of milk, to cool
the milk immediately after milking in a prescribed manner, to feed the
coAvs in a proper way, and to give notice at once in the event of disease
breaking out on the farm either in the case of persons or animals ; and, on
the other hand, to appoint inspectors charged with the carrying out of the
regulations and the superintending of the distribution of milk from the
central place. In institutions in towns where the milk treatment for invalids
is practised, or in institutions for the supply of children's milk, too great
care cannot be paid to cleanliness in the byre, to the animals, to the food,
to milking, to the whole subsequent treatment of the milk, and especially
to the health of the cows.

Up till now it has not been possible to devise precautions for prevent-
ing milk sold in the streets, from barrels in milk -carts and tapped by
means of a cock, from having the cream separated by rising to the surface,
and the customers from receiving milk of different values. If the milk be
not removed from the barrel by means of a cock, but be removed by
means of a measure, it is easy to provide e^'ery customer with milk of
equal quality. Milk-cans for milk-carts have recently been patented in
Germany, in which, by a special arrangement inside of the barrel, the
rising of the cream of the milk during distribution is prevented.
Experience has not yet demonstrated Avhether these cans fulfil the object
aimed at, and whether they are practically useful.

30. Milk Adulteration. — Cows' milk may be regarded as adulter-
ated whenever the average chemical composition differs in any
way, by the addition of foreign ingredients, from the average
composition of milk obtained by the continuous and perfect milking
of the udder of the cow. The milk adulteration that has to be dealt
with in practice consists in the watering of the milk, or in its
partial creaming, or in both creaming and watering. Occasionally,
but much more rarely than was at one time the case, milk is mixed
with skim-milk, which produces a similar effect to a partial removal
of the cream. Adulterations of any other sort are very seldom met
with in practice. On the other hand, the milk trade suffers from
many trickeries and intentional deceits, which are constantlj^ being
practised. For example, old milk, or milk collected from milk
remnants, is palmed off as fresh milk, or skim-milk is sold for
whole milk, or the seller gives false measure, and similar deceits.

( M 175 ) ^

66 SCIENCE AND I'llACTIUE OF DAIRYING.

According to the nature of the conditions under which, as has just
been described, milk is to be regarded as adulterated, every kind of
preservative used for milk must also be regarded as an adulterant.
Indeed, it may be concluded that there is something of a deceitful
intention in the secret use of such agents, since the buyer is under
the impression that the sweet condition of the milk is the result of
its fresh state, or of the careful and cleanly treatment to which
it has been subjected before sale, and is thus grossly deceived.

In former times, before much experience had been ol)tained in the
supervision of the milk trade, it was customary to draw up a formal list of
adulterants said to be found in milk, as well as methods for detecting all
possible and impossible adulterants, which Avere systematically arranged in
a tabular manner. Thus, in addition to the adulterants above referred
to, adulteration with albumin, white of egg, caramel, artificial emulsions,
meal, gum, dextrin, glue, bird-lime, soapy water, calcium and magnesium
carbonates, the pulverized brains of calves, sheep, and horses, and many
other things Avere spoken of. The large experience which has been gained
in the course of the last twenty years has shown that in Germany, at least,
hardly one of the above-mentioned and highly improbable adulterants
have been used. Further reference need not be made to them, since they
have no general interest, and if they ever Avere practised Avould, by means
of the iiresent methods of chemical analysis, be very easily detected.

31. Milk Testing. — In consequence of the adulterations of milk
described in § 30, it has to be determined, in testing milk, whether
the average chemical composition of the milk has been altered,
by external influences, after it has left the udder, so as to differ
from that of milk furnished by continuous and perfect milking,
and, in the case of any change having occurred, to discover the
nature of the influence that has produced the change. In the first
place, it is necessary to obtain as accurate a determination as possible
of the properties of the suspected milk ; in the second place, an exact
knoAvledge of the usual average chemical composition and the usual
nature of the milk obtained in that district; and thirdly, it is
necessary to have an ample knowledge, gained by experience, of the
limits of variation in the composition and specific gravity of milk.

Chemical analysis of all the constituents, and the determination
of the specific gravity, afford the most reliable evidence of the quality
of the milk. As, however, in earlier times it was only in very
exceptional cases possible to conduct such an investigation, it was

MILK TESTING. 67

necessary to form an opinion from single constituent properties of
the milk. For this object a number of so-called milk -testing
methods of a most varied kind were employed. In this matter
practice, more shrewd than theory, adopted the determination of the
specific gravity as affording the most valuable test. For a period of
ten years the importance of this test was quite undervalued on
account of the careless, unscientific method in which some early in-
vestigators carried it out, and it has only been re-established by later
investigations. Chemists on their side recommended the determin-
ation of one or other of the milk constituents, generally the milk-
fat, and, in addition to this, quite a number of other tests of milk.
Many of these tests were proved to be worthless on account of a
want of knowledge of their true sio-nificance, as well as because
they were often based on false assumptions, due to ignorance of the
true composition of milk. Owing to the advance in our knowledge
of the nature of milk, made since 1876, the improvement in methods
of chemical analysis, and the discovery of Soxhlet's areometric
method of determining fat — which gives results as reliable as
those obtained by gravimetric methods, and dispenses with the
use of the chemical balance, while it is simpler and more con-
venient to apply, — the older methods in use have been replaced,
and have now become antiquated; indeed they possess now only
historic interest.

For the purpose of judging milk, it is quite immaterial whether
the quantities of nitrogenous matter, milk-sugar, and mineral matter
are determined separately, or all together, as " solids not fat ". In
the first place, we know too little with regard to the variation which
these constituents — with perhaps the single exception of the mineral
matter — are subject to, to form a decisive opinion based on the
amount of any one of them. In the second place, the respective
ratio of the three constituents is not at all, or very slightly, altered
by such adulteration as is commonly met with in practice, so that it
may be said to give little assistance to our judgment; and thirdly,
in the case of watered milk, the diminution in the quantity of one
or other of these constituents furnishes us with no truer indication
than the diminution in the total quantity. At present, therefore, a
full analysis is seldom made unless we have to do with some
particular kind of adulteration. Instead of a full analysis, we
generally determine the specific gravity at 15° C. (s), the percentage
of fat (/), the percentage of total solids {t), the sum of the three

68 SCIENCE AND PRACTICE OF DAIIIYING.

above-mentioned constituents, i.e. the percentage of "solids not
fat " (r), and lastly the specific gravity of the total solids (m).

When it is desired to make an analysis of milk, it is of the
greatest importance to obtain a true average sample, this being
effected by thoroughly mixing the milk before taking the sample.
In this connection, it must not be forgotten how quickly milk
changes, owing to the tendency the fatty globules have to rise to the
surface. Thorough mixing of the milk, therefore, before taking the
sample, must never be neglected. When necessary, the milk should
be warmed to 40° C. before sampling.

Especial care should be taken in the determination of the sjDecific
gravity (.s), and to do so, if possible, up to the ten-thousandth
figure. For this purpose a glass hydrometer, of the Soxhlet pattern,
should be used, in which the divisions indicating thousandths should
occupy 7 5 mms. The temperature of the milk should also be
observed, and the results should be corrected, by means of correc-
tion tables, to the temperature of 15^ C. if the specific gravity has
not been taken at that temperature. Special attention ought to
be paid to the fact, that freshly-drawn milk yields figures from h
to TtroTjtb less than the figures yielded by the same milk, even
after the lapse of so short a period as three hours. On this account
one can only accept the specific gravity of milk as final when the
milk has stood for three hours from the time it was milked. The
fat (/) is determined, either by gravimetric methods or by Soxhlet's
areometric method, or with the lactocrit. If (s) and (/) have been
obtained, the total solids (t) may be calculated by means of formula
(3) given in § 11.

(1) < = ]-2x/+2-665^"Q^^-^QQ.
s

If, from the value found for (t), the value for (/) be deducted,
the value (r) (viz. the "solids not fat") is obtained:

{2)r = t-f.

From formula (7), given in § 11, the value of (m) (viz. the specific
gravity of the total solids) can be calculated:

(3) m:

■<-100xs-100

This value (m) is altered by creaming the milk, but not by water-
ing it. The knowledge of the five values, (/), (t), (s), (r), (m), is

MILK TESTING. 69

sufficient for most cases of adulteration occurring in practice, and
not only for an answer to the question as to whether milk is
adulterated or not, so far as this can be answered, but also for the
determination of the nature of any of the above-mentioned adul-
terations. Adulteration by watering is most easily seen in the
values (s) and (r), since both these values in unadulterated milk of
the most different origin vary between far narrower limits than the
values (/) and {t), as has been already mentioned in § 10. For this
reason the determination of the specific gravity of milk furnishes
the most important evidence for forming an opinion on it, not only
as a preliminary test, but also as a thorouglily reliable ground of
final judgment.

If, for example, (s) equals 1-0319, and (/) equals. .3-50 per cent, with
the aid of the table, the calculation is worked out as follows: —

For {t) the vahie in the tables is 1"2 x / for 3 -5 to 4-2, and the
value of

TOO X s — 100

2-665 for 1-0319 to 8-238 8 •24 therefore 13

8-240

■4-200
« = 12-440 percent, and 7- = 12-44 - 3-.';0 = 8-94 :

while for (m), by the tables, Ave find the vahie of
lOOxs-ino

- for 1-0319 to 3-091 ; tlierefore

12-440

3-091

'9-3l9 ) 12-440 ( 1-33

3-0910

2863

If milk with properties of this kind has been watered so that (s)
equals 1-0248, (/) will be found to equal 2-72 per cent, (/) to equal 9 71
per cent, (r) to equal 6-99 per cent, and (m) to equal 1-33.

If, in the case of creamed and watered milk, (i) equals 1-0270 and (/)
equals 1-695 per cent, (t) would be found to equal 9-041, (r) to equal
7-346, and (m) to equal 1-41.

By simply watering milk, the original values of (s), (/), (t), and (r)
are diminished throughout; while, on the other hand, the original A'alue
of {rn) remains unchanged, because the actual ratio of the individual con-
stituents of the dry substance does not suffer alteration.

By creaming, the original A-alues of (s) and (m) are increased, and to a
lesser extent that of (r); but the original value of (/) is very considerably
lowered, and that also of (f), but to a somewhat lesser extent.

SCIENCE AND PRACTICE OF DAIRYING.

If milk is both creamed and watered, and the Avatering has been
checked by the use of the hydrometer, or if the milk is only slightly
watered, the original values of (s) and (r) remain unchanged; indeed they
are even slightly increased. Generally, however, the values of (s) and (r)
are diminished. The original value of (m) is increased, while that of (/)
is very considei'ably diminished, and that of {t) to a less extent.

The areometric estimation of fat by Soxhlet's method has been so
universally adopted that it is not difficult for anyone to make himself

familiar with it. Its
principle is a very
happy one. The fat
in a measured quan-
tity of milk is dis-
solved in ether, and
the specific gravity
of the ether solution
at a certain tempera-
ture is determined
in an ingeniously
constructed appa-
ratus. From this the
amount of fat in the
milk is calculated —
the higher the spe-
cific gravity of the
solution, of course
the more fat does it
contain. As the
difference between
the specific gravity
of fat and ether is
considerable, far more than, for example, the difference in the specific
gra-sdty of milk and water, the specific gravity of the ether is correspond-
ingly changed by the addition of even a small quantity of fat. This
renders it possible to estimate the percentage of fat in milk with very
great delicacy. A greater advantage Avhich it possesses is that it esti-
mates, Avith almost an equal degi'ee of accuracy, the percentage of fat
in skim-milk as well as in Avhole milk.

In the case of the lactocrit (fig. 26), the coagulated portion of the
nitrogenous matter in a measured quantity of the milk, precipitated by
continuous boiling of the milk with a mixture of glacial acetic acid and
sulphuric acid, is first completely dissolved, and the fatty milk-globules,

Fig. 26.— The Lactocrit,

MILK TESTING. 71

which have been melted at the necessary temperature, thoroughly incor-
porated with each other, are enclosed in test-tubes, and subjected to centri-
fugal force in the lactocrit. The percentage of fat is estimated by the
observed vohune of melted fat. Originally this method was only utilized
in the investigation of whole milk. Subsequently, in 1890, the mixture of
acids was replaced by a quantity of ethylidene-lactic acid and solution of
hydrochloric acid, which perfectly dissolved the nitrogenous matter in the
milk, ^Wthout attacking the fat to any extent. The result Avas a great
improvement, both in accuracy and convenience, in determining the fat,
and a more extensive application of the method ensued. It enables a
determination of fat to be made in skim-milk and butter-milk, as well as
whole milk, if not directly, yet with great accuracy.

In the method devised l)y Marchand de Fecamp, which was investi-
gated and improved in 1878 by Schmidt and Tollens, the milk is treated
in a lacto-butyrometer with alcohol, ether, and a little potash. The fat is
dissolved and almost entirely separated in the surface layer of the ether.
From the volume of this layer the percentage of fat is calculated by means
of a table.

A fact which militates against the Marchand method is the retention,
in the lacto-butyrometer, in a dissolved condition, of a certain proportion
of fat. This amount, although generally the same, may vary under
certain conditions. In this method, therefore, conditions have to be
reckoned with which are not perfectly under control. All the improve-
ments made up to the present time in this jjrocess affect only the details,
such as greater convenience in Avorking it, more exact methods of reading
the degree, &c., and do not afiect the accuracy of the process. With
milk containing from 3 to 3j per cent of fat this method gives good
results, the variations from gravimetric methods being generally less than
•2 per cent. It is well suited for practical use in agriculture generally,
and is useful, for many purposes, in large dairies. For scientific work,
however, or for legal purposes, and for the determination of the commercial
value of milk, it is not sufficiently accurate to be relied vipon. It cannot
be used for solutions containing more than 1"339 per cent of fat. The
methods for fat determination already described, and more especially the
Soxhlet and lactocrit, are thoroughly accurate, delicate, and reliable
scientific processes.

Where it is impossible to estimate the percentage of fat, and the
above methods of milk -testing are consequently inapplicable, a
milk-test devised by Miiller may be found to serve the purpose.
The specific gravity at 15° C. is determined, and the milk is allowed
to stand for 24 hours in a Chevalier cremometer at a temperature

72 SCIENCE AND PRACTICE OF DAIRYING.

as near 15° C. as can be obtained. The depth of the cream layer
is noted for the purpose of calculating its percentage volume, after
which it is removed. The specific gravity of the skim-milk at
15° C. is then determined, so that it may be seen whether it remains
within the usual limits. This method has been found extremely
useful for testing milk suspected of having been creamed and
watered, especially in hilly districts, where the conditions of milk
production do not exhibit such wide variations as are often found
in some districts of flat lands.

The "byre -test" furnishes a complement to this formerly
largely-used method of milk-testing.

The byre-test is carried out in the following manner. If, on investiga-
tion, a sample of milk of known origin is found to yield unusual results, the
byre is visited as soon as possible and the milk investigated. The results
thus obtained are compared Avith the previous ones, so that it may be
ascertained whether the earlier results are confirmed. Where the results of
the byre-test are to be given as evidence in a court of justice, the test
must be carried out in the presence of witnesses, and care should be taken
that the cows are thoroughly milked. It is advisable, therefore, that a
skilled milker should be employed, or that the operation should be carried
out under his directions and to his satisfaction. The quicker the byrc-test
follows upon the seizure of the sample of milk, the more valuable are its
results for purposes of proof. Tlie same milking-time as that at Avhich
the suspected sample was obtained should be chosen, as Avell as the same
cows Avhich have been milked, and the test, if possible, should be applied
within 24 hours, and in no case should more than three days be allowed
to elapse. It is necessary generally to submit the milk coming from the
Avhole of the cows in question to investigation. In this Avay the milk of
each single coav can be tested. If no important change in the feeding
and treatment of the cows haA^e taken place in the interval betAveen the
time of the milking of the suspected sample and the milking of the sample
taken for the byre -test, then the duplicate results, in the absence of
adulteration, should show a variation of not more than a tAvo-thousandth
in specific gravity, equivalent to a difference in fat of not more than
•3 per cent, and a diff"erence in the total solids of not more than 1 per
cent. AVhere larger variations than the above are found, then the sus-
picion of adulteration is confirmed, and in some cases may be absolutely
proved. Caution must always be exercised, hoAvever, since it has been
noticed occasionally — in very feAv cases, it is true — that the specific gravity
of the milk of single coavs has shoAvn a diff"ercncc, from day to day, of
several thousandths, indeed, as many as six, and a diff'erence in the

MILK TESTING. 73

jiercentage of fat of from 2 "5 to 3 per cent. As a result of the author's
own experience, he has found that the byre-test is only valuable Avhere tAvo
milkiugs per day are generally practised, and where the conditions of
milking in all the byres from which the milk is collected are essentially
similar, as is the case, for example, in many districts of Switzerland,
Austria, and the hilly districts of South Germany. As far as Noi-th Ger-
many and the middle districts of Germany are concerned, where the con-
ditions vary greatly in the different byres, it is absolutely worthless.

For the detection of the less common adulterants of milk, such
as the presence of poisons, or the identification of bacteria, it is
obviously impossible in this work to give a more detailed descrip-
tion of the mode of investigation which must be adopted.

In the case of the milk of single cows, the question as to whether
it is adulterated or not is a most difficult one to decide. With
market milk, however, which almost invariably represents the milk
of a number of cows, it is not so difficult; while in cases where the
milk of the larger herds is concerned, the detection of adulteration is
rendered much easier. The fixing of standards by which the purity
of milk should be determined is almost impossible. We shall, at
any rate, not attempt to lay down any limits of composition to which
the unadulterated milk of single cows is subject. Such figures would
not be of any assistance in forming a judgment. The following
figures which the author quotes, and which aj^ply to market milk,
in which the variations found in the milk of single cows are
neutralized, are therefore to be used with very great caution. In
the majority of eases of German milk, produced under ordinary
conditions, the following figures may be taken as showing the
variations in its composition: —

Specific gravity at 15° C. a variation from 1029 to 1033.

Fat, ... ... ... ... 2-50 per cent to 4-50 per cent.

Total solids, 10-50 „ „ 11-20 „

Solids not fat, 8 „ „ 10

The specific gi\avity of the total solids should not exceed 1-400.

It must be strongly emphasized that the above figures, wliich
apply to market milk, must not, in any case, be held as applying
universally; but they may be found to hold fairly well in the
majority of cases. In different districts of Germany, however, they
must, in one or other of the particulars, be departed from. Also, it

74 SCIENCE AND PRACTICE OF DAIRYING.

must not be assumed that milk which differs in composition from
the above-stated figures is consequently adulterated, but merely
that milk, in which this is the case, possesses unusual properties,
which warrant suspicion, and justify further testing for its purity.
It can also hardly be contended that the occasional variation of
milk from any one of the above figures points to adulteration.
Adulteration on a small scale is, as a rule, impossible to detect in
milk.

The opinion of anj^one with regard to the genuineness of a
sam^ole of milk, who has not taken the precaution, during a year at
least, of making himself familiar with the conditions of treatment
and the j)i"operties of milk, in the districts where the milk-tests are
carried out, and who has not performed a very large number of
milk analyses, is not worthy of regard. The same may be said
also of anyone who neglects to take into consideration a proper
study of the action of all the influences which affect the secretion
of milk.

We have already considered the nature and properties of cows' milk,
and of the influence which interrupted milking of the cows, or incomplete
milking (not milking dry), or of milking at irregular intervals, exercises
on the composition of milk. The variations Avhich the composition of milk
from day to day and from milking-time to milking-time exhibits, in short,
all the influences which aff'ect the secretion of milk, and which have to be
taken into careful consideration in the testing of milk, have already been
treated in Chapter I.

32. The Supervision of the Milk- trade in Towns. — This has to
do, in the first place, wdth the discovery of the sellers of suspected
samples of milk, and, in the second place, with the discovery of how
and in what manner the milk has been adulterated. The police
supervision of the milk-trade in towns is consequently of a double
character, viz. the preliminary testing at the place of sale, and the
formation of a final judgment by an experienced and skilled analyst.
Careful observations should be constantly — if possible daily — insti-
tuted at the places of sale, and the appearance, smell, flavour, and
reaction of the milk should be tested. The specific gravity should
be taken with a correct hydrometer, and an observation of the tem-
perature of the milk also made. A determination of the percentage
of fat, by means of a lactoscope, should perhaps also be made. It
should also be noted whether the capacities of the milk-vessels are

THE SUPERVISION OF THE MILK-TRADE IN TOWNS. 7o

of the proper standards, and if the measures of the seller are correct
and jjroperly stamped. In the supervision of places for the sale of
milk, only practised and experienced men should be employed.
When it has been thoroughly mixed, an average sample of the milk
is taken and transferred to the specially-prepared bottle, which is
corked and sealed. This should be accompanied, if possible, by
exact details furnished by the seller as to the source of the milk.
The examination described in paragraph 31 should then be carried
out.

The rough practice of many under-oflicials, cliai'ged with the arbitrary
power of directing that all milk which does not come up to the standards
of purity should be poured into the sewers, is unworthy of the present
time. It is, in short, destroying a food which has only been partly robbed
of its nutritive properties.

Supervision of the milk-trade in towns, which limits itself to
the prevention of fraud and gross adulteration, can only be said to
be fulfilling half its functions. There are other duties which it
ought to perform in the protection of the connnunity, and in the
furtherance of general health — duties which may be described as
even higher and more important. It should see:

(1) That the milk exposed for sale is not only unadulterated,
but that it is of such a quality as is obtained by the perfect milking
and thorough admixture of the entire milking of a single cow, or of
the milk of several cows.

If, in the case of large quantities of milk, thorough mixing does not
take place before it is separated into the sale cans, it is quite impossible
that the percentage of fat in the contents of the single milk-cans should
be the same. Milk sold under such conditions favours one customer at
the expense of another.

(2) It is desirable that, for the purposes of cooking and churning,
the milk should possess the ordinary (normal) properties of good
milk, and should be devoid of abnormal properties.

Milk with any uncommon properties, such as, for example, colostrum
milk, milk showing any of the milk -faults, milk containing coagulated
masses or lumps of butter, milk Avhich exhibits lunisual behaviour Avhen
treated with rennet or when boiled, and milk which shows an unusual
bluish-white coloiu-, or a strange smell or taste, should never be allowed to
come to the market.

76 SCIENCE AND PRACTICE OF DAIRYING.

(3) Only sweet milk, which remains unchanged at ordinary
temperatures, for some time after sale, without becoming coagulated,
and which stands boiling, should be provided.

(4) The milk should be worth its price, that is to say, it should
have the average percentage of total solids and fat, found in the
milk which is obtained in the respective districts, from properly-fed
and Avell-tended cows.

(5) Only milk which comes from healthj^ cows, free from foreign
ingredients, and uncontaminated with pathogenic germs, should be
sold.

The milk of cows which have had fever, or have been treated internally
or externally with medicines, is unsuitable for sale. Care ought also to
he taken that the milk is kept clear of contact with people suffering from
infectious diseases, or people having charge of such persons.

The stringent demands which we are justified in making at
present on the milk-trade, and which in some places are beginning to
be timorously enforced, Avill become more easily and more perfectly
granted the more the milk-trade is concentrated. The supervision
of the sale of milk is uncommonly difficult in towns in which the
sale of half-milk, that is, a mixture of creamed evening milk with
whole morning milk, is practised.

In addition to milk, cream, skim-milk, butter-milk, and whey
are sold in commerce.

Cream, as it is usually sold, contains fi'om 11 to 25 per cent of fat;
hut the Avant of definite regulations concerning its sale has never been
felt. The same may be said with regard to butter-milk and whey, which
only come into the market in small quantities. With regard to the super-
vision of the trade in skim-milk, Avhere it is desired, the tests should be
limited to its appearance, smell, and flavour, and to ascertain whether il
stands boiling, and is free from unusual properties. The determination
of the specific gravity (which in the case of skim-milk obtained from
centrifugal machines generally containing not more than "5 per cent of fat,
varies between r0335 and 1-0360) will reveal the addition of any large
quantit}?^ of water. Since the high value Avhich skim-milk possesses as a
nutritive food depends entirely on its percentage of albuminous mattei-, it
is quite immaterial whether it contains a tenth of a per cent of fat more
or less; and for this reason it is quite Avrong to jirevent its sale unless it
has been proved to contain a certain j)ercentage of fat.

The analysis and testing of skim-milk is carried out very much

THE SUPERVISION OF MILK IN LARGE DAIRIES. t i

in the same way as that of sweet-milk. Further details will be
given in Chapter III.

33. The Supervision of Milk in large Collecting and Co-operative
Dairies. — In the interests of the milk trade, it is necessary that the
milk coming from each separate dairy should have its appearance,
taste, and smell tested. Its temperature should also be taken, in
order to see if it has sufficiently cooled down after milking. It is
further necessary to ascertain whether it has been contaminated
with dii't, to determine its specific gravity, and to see that the
vessels used for carrying it are suited for the purpose. The milk
should be tested by boiling it, and a preliminary estimation of its
fat should be made. If the milk from an}' dairy appears suspicious,
an average sample should be taken, with all due precautions, before
witnesses, and sent for accurate analysis to the nearest public
chemical laboratory. At the same time, in order to hinder as much
as possible any fermentation during transit, the milk should be
cooled in ice before being sent away, and every endeavour should
be made to hasten the transit. Since the conditions of clear profit
are greater the richer the milk is in fat, the managers of dairies
should make a point of discovering those suppliers who send in
unusually poor milk, and they should either cease dealing with
them, or should induce them to increase gradually the percentage
of fat in their milk. The best way of avoiding the imposition
which is daily practised, when milk of varying value is simply
sold according to weight, consists in buying it from producers at
so much per kilogram according to the percentage of fat it contains,
in short, in selling it according to the percentage of fat it contains
as well as according to its weight.

In order to carry out thi.s method of purchase, it is necessary that the
milk obtained from each supplier be regularly tested by some method
or other for its percentage of fat. If such tests are not made often
enough, it can hardly be expected that reliable data Avill be available
for ascertaining what the true average percentage of fat of single milk
consignments really is, for it is not impossible that, in the case of an
incorrect average being taken, the payment for milk may be as far, or exen
further, from being a just one than is the case in buying milk of vaiying
value simply by weight; and thus all the trouble and expense involved
be really of no use. To obtain reliable data the milk of each customer
should be examined at least once a week.

If in any district — and in Germany there arc many such districts—

78 SCIENCE AND PRACTICE OF DAIRYING.

the external conditions under which milk is obtained are similar, and the
single consignments of milk differ comparatively little in their relative
percentages of fat, it is not worth the trouble of introducing this costly
and inconvenient method of milk valuation.

If all parties are agreeable, the lacto-butyrometer may be used for
investigating the milk. The Soxhlet method, however, is by far the
better one. Where it is impossible to overtake the number of milk inves-
tigations that are required to be made hy this method, the lactocrit may
be used. This process, even where a large number of investigations have
to be made, is not likely to give unreliable results. According to the
author's experience, where the number of fat determinations amounts to
30 per week, or to 1 5 determinations twice a week, it is almost as cheap —
despite the high price of tiie apparatus — as the Soxhlet method; and
where the number of determinations exceeds this, the cheaper, propor-
tionately, does it become. One worker, provided he is supplied with
assistance in the cleaning of the apparatus, &c., can easily undertake the
determination of fat in more than 100 samples of milk daily, and in over
600 samples in a week. The indirect determination of the percentage
of fat in milk by means of the thickness of the cream layer, as, for
example, by the Fjord milk-control apparatus, is noAv quite antiquated,
especially for the purpose here referred to.

With regard to the method of fixing the price jDer kilogram of milk,
according to the percentage of fat it contains, reference Avill be made
in § 145

In dairies in which cream cheeses are made out of the milk
obtained from different dairies, where any difficulty may occur, the
so-called milk-ferment test and the rennet test are useful.

For the carrying out of the milk-ferment test special apparatus is
required. The improved milk-ferment apparatus of Walter, or that of
Denkelman, known as the lacto-fermentator, for example, may be used.
In the application of this test, the milk of each milk-supplier is set in small
quantities, in suitable vessels, for some time (12 hours) at a temperature
of 40° C. At this temperature the action of injurious low ferments which
may be present is developed more quickly than at the ordinary tempera-
ture. Pure milk, under the above conditions, coagulates into a cohesive
homogeneous mass, resembling the albumin of a boiled egg, and possessing
a pure acid smell. If the milk in any of the vessels has not become
coagulated, or presents a ragged, flocculent coagulation, floating in a
muddy serum, or occurs in non-homogeneous slimy clots, full of gas-bubbles,
and possesses, instead of the purely acid smell, a strange, unpleasant
odour, it is to be inferred that the milk which this sample represents is

SUPERVISION OF PRODUCTION AND MANUFACTURE OF MILK. 79

likely to impair the quality of the cheese. If, on repetition of the
experiment within the next few days, similar results are obtained, and if
the quality of the cheese is unimpaired so long as this questionable milk is
ex.;luded, it is quite justifiable to hold the supplier of the contaminated
milk responsible for any damage that may have arisen.

Just in the same way as the milk-ferment test renders it possible to
trace milk contaminated with deleterious fungoid growths, the rennet test
renders it possible to detect milk which possesses unusual properties, and
which would exert a deleterious action in cheese-making. The rennet
test is applied in the same way as is done in testing the strength of
rennet, and consists in treating with rennet the milk Avhich is being
investigated, and observing whether it coagulates quickly or slowly, or
whether it coagulates at all, and whether the coagulated mass obtained
possesses the ordinary properties.

34. The Supervision of the Production and Manufacture of Milk.
— In the supervision of milk production in country districts, all
that can be done is to take care that the cows are fed as suitably
and richly as circumstances permit, and that regular tests of the
milk are made as above described. This object will be attained if
similar quantities of butter are made from equal quantities of milk
obtained from a mixed herd of cows. As this is not always the
case, and as the average percentage of fat in the milk of cows
differs very much according to their surroundings, attention must be
paid not only to the yearly quantity yielded by each cow, but also
to the quality of the milk, in order to utilize the most valuable cows
for breeding purposes. Those that yield a less satisfactory return
ought to be removed, and in this way it will be possible gradually
to increase the yield of the entire herd. If sufficient attention has
not hitherto been paid to the quality of the milk, the neglect has
been chiefly due to the fact that a correct hiethod for the determin-
ation of the percentage of fat, which could be carried out at once
rapidly and easily, and \A'hich was at the same time accurate and
reliable, was awanting. The Foser Lactoscope, formerly recom-
mended for this purpose, no longer satisfies present demands. Since
the lactocrit has been devised, however, and has been proved to be
as handy as it is reliable, a regular testing of the milk of single
cows for its percentage of fat, especially in large herds, is no longer
so ver}^ diflBcult to carry out. It is to be hoped that a reliable
method of determining fat will soon be discovered, so convenient
and at the same time so cheap that it may be capable of being

so SCIENCE AND PRACTICE OF DAIRYING.

employed on small farms. A wide field of activity still remains in
Germany, which has hardly yet been entered upon, for efforts for
the purpose of increasing the milk yields and the capacities of cows,
in which amply repaying success and a rich return for the money,
time, and trouble spent, can be safely promised.

Perhaps it may be also necessary to pay attention to the adapta-
tion of the calving-time of cows, in the most advantageous manner,
to the different agricultural conditions, to the intermittent yield
of the cows, and to the recurrent variations in price that commonly
occur throughout the year. In general, these conditions have
hitherto received too little attention.

In the supervision of the utilization of milk, the first duty is to
strictly maintain the most absolute cleanliness in the byre, in the
milking of cows, and in the treatment of milk. Care should also
be taken that milk-cows are well treated, and are thoroughly
milked at each milking, and that the milk of diseased cows, or
milk exhibiting any unusual properties, should not be utilized, and
that the milk should not come into contact with sick persons. In
dairying, only careful, capable adult dairymen should be employed,
and the arrangements should be such that every operation should
go on smoothly, and that every precaution adopted should be efl'ec-
tively carried out. A simple tabular list of instructions of dairy
and technical details, which should include hints on branches of the
business of dairying, should, without fail, be put on the walls of
byres and dairies. Finally, it is to be recommended that samples of
milk, skim-milk, and butter-milk should from time to time, if no
other method offers, be sent to a research station to be tested for
the percentage of fat, in order that the dairyman should be in a
position to judge whether the yield of butter corresponds to the
percentage of fat, and if not, to what extent it is deficient.

35. The Analysis of Milk. — It is not difficult to make one's self
familiar with Soxhlet's widely used apparatus for the determina-
tion of the percentage of fat in milk, or with the working of the
lacto-butyrometer and the lactocrit. Opportunities for this purpose
are easily obtained. Opportunities for becoming acquainted with
the method of carrying out the full analysis of milk occur less
frequently. The detailed description of the nature and properties
of milk given in earlier paragraphs must have excited a desire to
obtain at least a description of the methods which render it possible
to determine the single constituents of milk, and to estimate their

THE ANALYSIS OF MILK. 81

percentage. Chiefly for the purpose of satisfying this desire, a short
description is given in what follows of how an analysis of milk is
made.

Before proceeding to the analysis, the milk is tested in respect of its
appearance, smell, taste, and reaction. Its specific gravity is taken at
15° C, and it is tested by boiling. The action of rennet on it is also
tested and its percentage of cream estimated by allowing it to stand for
24 hours at from 12° to 18° C. in a Chevalier cremometer. Further, it is
desirable, where possible, to obtain information as to whether the milk is
from one cow or from several, Avhether milking is carried on in the byre
from Avhich it has come, twice a day or oftener, and from Avhich milking
the milk comes. Particulars with regard to breed, treatment, feeding,
age, length of time after calving, general health of the cow, and the method
in which the sample has been taken, so as to decide whether the analysis
represents correctly the composition of a milk such as should have been
obtained under these conditions, should also be obtained.

When a sample of milk is drawn for analysis, the milk should not
only be thoroughly mixed, but should also be brought always to the same
temperature, for example, 15° C.

Deter inination of the Percentage of Trater, or of Total Solids. — Into a thin
porcelain basin is placed 15 grams of washed, ignited sea-sand which has
been treated with hydrochloric acid. The basin with the sand is dried at
100° C. till the weight is constant. It is then removed to a desiccator,
and, after being cooled, is weighed. About 30 c.c. of milk are then poured
into a clean small beaker of about 40 c.c. capacity, and a small glass stirrer
which does not reach above the lip of the beaker is added. The beaker is
covered with a watch-glass and weighed. After removing the watch-glass
and stirring the milkAvith the stirrer about 10 c.c. of the milk are poured
over the weighed sand in the porcelain vessel, the watch-glass is again
replaced and the beaker weighed. The difterence between the two weigh-
ings gives the weight of the milk used. This is added to the weight of
the vessel containing the sand. Drying is first carried on in the water-
l)ath ; the porcelain basin with its contents is then introduced into the
drying-bath and dried for 45 minutes at 100° C, and then for 15 minutes
at 105' C, cooled in the desiccator and weighed. It is then introduced
into the drying-oven for 30 minutes at 100° C, again cooled in the desic-
cator, and again weighed. This is repeated until two successive weighings
show no greater difference than 1"5 mg. The loss in weight, subtracted
from the original weight, represents the weight of the water driven off,
and by suljtracting this from the weight of the milk used, the weight of
the total solids is obtained.

{ M 175 ) *"

82 SCIENCE AND PRACTICE OF DAIRYING.

If in the same samjjle of milk two determinations of the total solids be
carried out, it is quite possible that, despite the greatest care, a difference
of plus or minus '15 per cent may be obtained. This difference may be
chiefly ascribed to the peculiar behaviour of the dissolved milk-sugar when
being dried, as has been already described in paragraph 7. The experi-
mental errors in the determinations of the total solids may therefore
amount to plus or minus "15 per cent.

If the exact percentage of fat and the specific gravity of milk be
obtained, the percentage of total solids can be calculated from the formula
given in § 11. The correctness of this determination is as great or greater
than the indirect determination, and can be used in corroboration.

Determination of the Percentage of Fat. — For this purpose the residue
obtained in the determination of the total solids can be utilized. It is
better, however, to weigh out 10 to 12 grams of milk in the way pre-
viously described, using a roomy porcelain dish, about 10 centimetres
in diameter, with as much sand as will perfectly absorb the milk, and
then to place this on the Avater-bath. In order to prevent the milk from
sticking firmly to the porcelain basin, it should be stirred with a small
sharp -edged glass stirrer. As soon as the mass shoAvs a tendency to
become cohesive, the whole should be stirred and all the little lumps
broken up before they become hard, so that eventually one obtains a
uniform coarse powder. If this does not become baked to the slightest
extent after remaining 15 minutes undisturbed in the water-bath, it is
rubbed with a small porcelain pestle, which is allowed to stand in the
middle of the basin. It is retained 15 minutes longer in the water-bath;
the powder is then carefully removed, every single particle being cleared
from the vessel on to a Swedish filter - paper which contains no fat,
shaped in the form of a cylinder, and resting on glazed pajier. It is then
introduced into the tube of a Soxhlet fat - extraction apparatus. The
paper cylinder is made by Avrapping a piece of filter -paper cut at right
angles twice round a Avooden cylinder, the diameter of Avhich is about
4 mm. less than the diameter of the extraction tube, and then placing
on the level surface of the Avooden cylinder a piece of paper of similar
diameter to the roll, bending this, and smoothing doAvn the surface as
one Avould close a packet. It is unnecessary to use a plug of cotton avooI
under the coil in the extraction apparatus. It is better to place some
cotton Avool, free from fat, above the coil, to prevent any Avashing out
of the poAvder by the falling drops of the ether. In order to prevent
the opening of the syphon at the base of the extraction cylinder from
being closed by the coil, a ring made out of a strip of pure tin 3 to 4 mm.
broad is used. The upper surface of the cylinder should be at least
3 mm. under the highest point of the syphon bend of the extraction

THE ANALYSIS OF MILK, 83

apparatus. Care must be taken that the coil should not be filled with
cotton wool to its highest surface, and that the ether which comes from
the condenser attached to the apparatus Avhen the extraction is going
on should always drop in the middle of the coil. After the coil is placed
in the extraction apparatus, a wide-necked weighed flask containing 25 c.c.
of pure ether is attached to the lower end of the extraction apparatus.
The porcelain dish which has been used, along with the glass stirrer and
pestle which have been used, are repeatedly i-insed out with ether, Avhich
is then poured on to the coil in the extraction apparatus. .Sufficient
ether is then added to the extraction apparatus till the syphon is almost
full, a condenser is then fixed on above, the wide-necked flask placed in
a sand-bath, the temperature of which is maintained at about 60° C,
and the extraction is started. As a rule, it is ended in about three hours.
AVhether this is long enough, or whether the extraction requires to be
continued for a longer period, can be proved by the watch-glass test.
After the extraction has been finished the flask is taken off", and after the
ether has been slowly distilled it is placed in the drying-bath, dried for
45 minutes at 100° C, and then for 15 minutes at a temperature of from
105° to 110° C, cooled in the desiccator, and weighed. The flask is again
introduced into the drying-bath, dried for 30 minutes at 100° C, allowed
to cool, and weighed again; and this is repeated until the two last
weighings are found to show no greater difference than 1 milligram.
Nearly always from 60 to 90 minutes is sufficient to efTect thorough
drying. If the fat has to be determined in skim-milk, sea sand is not
used, but gypsum. A larger quantity of this is vised than is necessary to
absorb the liquid, and the extraction lasts for at least four hours before
the watch-glass test is applied for the first time. The limits of experi-
mental error for milk may be stated at, for Avhole milk, plus or minus,
•05 per cent, for skim-milk, plus or minus, -03 per cent. The determi-
nation of the fat by the Soxhlet method gives equally exact results. The
extraction apparatus must be firmly connected with the fat flask, and
the condenser to the apparatus. The thi'ee pieces of apparatus should not
be attached to each other Avith cork.

A much simpler method, and perhaps even a more accurate one in its
results, for the estimation of fat, is Adams' process, in Avhich the milk is
dried on blotting-paper.

A coil of filter-paper, 56 cm. long, and 6'5 cm. broad, Avhich has been
previously treated Avith ether to remove any trace of fat it may contain,
is alloAved to absorb from 8 to 10 grams of milk, Aveighed out from a
beaker by difference as above described. After a feAv minutes, and Avhen
the milk has thoroughly soaked in, the coil is hung on to a peg in the
drying-bath and alloAved to dr}^ for an hour at 97° to 98° C. The coil is

84 SCIENCE AND PRACTICE OF DAIRYING.

then placed in the extraction ajiparatus and extracted for three hours, and
the weight of the fat extracted is estimated. If the roll after extraction
is once more dried for half an hour and is weighed, and the original weight
of the strip of paper is subtracted from the weight thus found, the weight
of the non-fatty solids is obtained. The sum of the non-fatty solids and
the fat gives further the total solids.

Determination of Percentage of Nitrogenous Matter. — This is carried
out according to the method recommended by Ritthausen, which is as
follows: — 2.5 c.c. of milk are measured off, weighed, and diluted with
400 c.c. of water. 10 c.c. of a copper sulphate solution (69 "28 grams of
pure salt per litre) are added, and then 6*5 to 7*5 c.c. of a potash solution
of such a strength that 1 volume of copper is precipitated for each
volume of the copper solution. The solution, after addition of the alkali,
must be neutralized Avith acid till it possesses a weak acid reaction,
and may contain a little copper in solution. The precipitate falls down
rapidly, so that the supernatant liquid can be quickly filtered through a
dried weighed filter, and the precipitate quickly washed by decantation and
brought on to the filter. The filtrate, along with the washing water, can
be used for the determination of milk-sugar; and the copper precipitate,
Avhich, in addition to the entire mass of nitrogenous or proteid matter com-
bined with the copper, contains also all the fat which is in the milk, may be
used for the quantitative determination of the fat. In any case the fat has
to be extracted from the precipitate. For this purpose it is washed Avith
a small quantity of absolute alcohol, any particles of the precij^itate
adhering to the filter being carefully removed Avith a platinum spatula,
and broken up as much as possible and extracted Avith ether, either on a
glass funnel or in the Soxhlet fat-extraction apparatus. If a quantitative
determination of the fat is desired, the alcohol and ether Avashings may bo
evaporated and the residue Aveighed. The precipitate from which the fat
has been extracted is still further treated Avith absolute alcohol, and is dried
immediately afterAvards until it becomes of a bright blue earthy colour, and
easily friable. It is then placed in the drying-bath at 125° C. until its
Aveight is constant. As soon as the weight is constant it is carefully
ignited, at first at a Ioav heat, so that the easily combustible proteid sub-
stances in combination are entirely burnt off. From the loss in Aveight the
amount of albuminoids contained in the milk is estimated. This estima-
tion is liable to a small error (about "08 per cent), and is by that amount
too low, since in the ignition residue the sulphuric acid formed by the
oxidation of the sulphur of the albuminoids is estimated Avith it. It is
necessary to examine the ignition residue for its percentage of carbon,
and if any is found, to Aveigh it in a weighed filter-paper, and to calculate
it to the loss on incineration, Avhich represents the jiroteid substances.

THE ANALYSIS OF MILK. 85

If it be desired to estimate the casein by itself, 25 grams of milk are
diluted Avith eleven times their volume of water, carefully precipitated
with acetic acid, and the precipitate collected on a dried and Aveighed filter,
'riic precipitate is Avashed, extracted from fat, and dried at 110^ C, till the
Aveight is constant. It is then burned, and the weight of the ash deducted
from the first obtained Aveight. According to the method of J. Lehmann,
the casein may be determined by the application of porous clay plates.
The albumin is estimated by heating filtrate and A\'ash-Avater got in the
tletermination of the casein to boiling temperature. The clot thus obtained
is collected on a dried and Aveighed filter, Av^ashed, extracted from fat, and
dried to a constant Aveight at 110° C, and the Aveight of the ash obtained
after burning is deducted from the Aveight thus obtained. The percentage
of so-called lacto-protein may be estimated in the filtrate and Avash-Avater
from the determination of the albumin by means of the method of
liitthausen, by using copper sulphate and potassium hydrate.

Determination of Milk-sugar. — ^The determination of the milk-sugar, if
not effected by means of the polariscope, is best carried out according to
Soxhlet's method. 25 c.c. of milk ax-e Aveighed out, and diluted Avith
400 c.c. of AA'ater, then first treated Avith 10 c.c. of sulphate of copper solu-
tion (69'28 grams of copper sulphate per litre of Avater), then Avith 6*5 to
7 '5 c.c. of potash solution of such a strength that one A'olume of copper is
precipitated for every volume of the copper solution. After the addition of
the alkali, the solution must be neutralized and rendered slightly acid, and
may contain a little copper in solution. It is then made up to 500 c.c. and
filtered through a dry folded filter. 100 c.c. of the filtrate is treated Avith
50 c.c. of Fehling solution in a beaker, Avhich is then covered and brought to
the boil over a double Avire gauze. After it has been boiled for six minutes
it is filtered through asbestos, and the reduction of the copper takes place
spontaneously in the asbestos tube. A small straight calcium chloride tube
(about 1 2 centim. long and 1 -3 centim. Avide), Avhose bulb is half protected
by oblique and not too soft asbestos filaments, is Avashed, then dried OA'er
the naked flame Avhile air is draAvn through, Aveighed, and attached to
a filter pump. Filtration is then carried on by pouring through an
attached glass funnel in the presence of a Aveak diluted atmosphere, then
Avashing Avith water, and, after the filter pump has been detached, tAvice
with absolute alcohol and twice Avith ether. Thereafter the filter tube is
removed, stretched, and, after the ether has been for the most part
expelled by air, bent on a holder doAvuAvards, its upper Avide opening
connected with a Kipp hydrogen apparatus, then the copper suboxide
very carefully heated over a small flame, the top of Avhich is about 5
centimetres under the bulb. The reduction is complete in about tAvo or
three minutes. After the asbestos tube has been cooled in a stream of

SCIENCE AND PRACTICE OF DAIRYING,

hydrogen, air is drawn through and it is weighed. If, after Aveighing,
the metallic copper is dissolved in dilute nitric acid, the tube, after being
M^ashed out and dried, but reduced 10 to 15 rag. in weight, may be used
again. The estimation of the milk-sugar from the weight of the coppei',
after Soxhlet: —

392-7 mg. copper represent 300 mg. milk-sugar.

363-6 ,

275 „

3330 ,

250 „

300-8 ,

225 „

269-6 ,

200 „

237-5 ,

175 „

204-0 ,

150 „

171-4 ,

125 „

138-3 ,

100 „

For example, if the copper found weighs -291 grams, according to the

table this shows

225 X .291

300-8

= •2177

grams of milk-sugar in 5 c.c, that is, 4-354 grams in 100 c.c. of milk, or,
if 100 c.c. of milk weigh 103-1 grams, 4-223 per cent of milk-sugar.

The filtrate which is obtained in the Ritthausen process as above
described in the determination of the proteid substances may be used for
the determination of the milk-sugar.

Determination of the Ash. — 25 grams of milk, after the addition of a few
drops of acetic acid, are heated to hard dryness on the water-bath in a
platinum capsule, and then slowly incinerated over an open flame. The
residue, after being boiled several times with water, is burned to a white
ash. The platinum capsule is then placed in a water-bath, the watery
extract slowly added, evaporated, and then slowly ignited, allowed to
cool, and weighed. If milk samples which have been already Aveighed out
for investigation are not immediately analysed, care must be taken that
they are kept at a temperature under 12° C, and for only about 48 hours.
If the samples are kept longer or are placed in a higher temperature,
considerable loss in the total solids may be expected.

In addition to what has been above described, Ave may add one or tAvo
details Avith regard to points Avhich may crop up in the testing of milk.
In the year 1883, Uff'elmann suggested that since ordinary spring and river
Avater almost ahvays contained ammonia, nitric acid, or nitrates, bodies
which are never found in uncontaminated milk, these might be taken as
an indication of the addition of small quantities of river Avater to milk.
Unfortunately, hoAvever, the proof of the addition of Avater to milk
through the diphenylamine reaction of nitrates and nitric acid is not of

THE ANALYSIS OF MILK. 87

such a nature as to permit of its practical application in milk-testing.
Nor Avould this test be very valuable in view of the many adulterations
which it would fail to detect.

The proof of the addition of carbonates or alkali bicarbonates is most
easily obtained by incinei'ating 300 to 500 grams of milk, and determining
the percentage of carbonic acid in the ash. The ash of unadulterated milk
does not contain more than 2 per cent of carbonic acid ; while anhydroua
carbonate of soda contains 41-5 per cent. If the percentage of carbonic
acid in milk exceeds 2 per cent, this may be regarded as a certain indi-
cation that an alkaline carbonate has been added to the milk. Even an
addition of 1 -5 grams of anhydrous soda to a litre of milk imparts to it a
distinct soapy taste. In Hilger's process 50 c.c. of the milk are diluted
Avith five times the quantity of water, coagulated with a small quantity
of alcohol, and filtered. If the filtrate be evaporated to half its bulk, an
alkaline reaction indicates the presence of an alkaline carbonate.

The presence of salicylic acid in milk is best detected by Pellet's
method. 100 c.c. of the milk to be investigated, 100 c.c. of water at 60^ C,
five drops of acetic acid, and five drops of a solution of mercury oxide in
nitric acid are mixed together, shaken, and after the albumin has been
coagulated the mass is filtered. The clear filtrate is then shaken with
50 c.c. of ether. After the ether has separated out it is removed, placed
in a clean vessel, diluted, the residue dissolved in a few drops of water,
and tested to see if it will give, on the addition of two drops of a 1 -per-
cent solution of iron perchloride, a violet coloration. If it shows a
coloration, its amount can be determined by comparing the depth of
colour produced with a standard solution of salicylic acid and iron per-
chloride. The amount of salicylic acid can in this a\ ay be approximately
determined.

In order to test the quantity of boracic acid in milk, Meissl recommends
the follo-vving process: — 100 c.c. of milk are rendered alkaline with milk
of lime, evaporated, and incinerated. The ash is dissolved in the least
possible amount of concentrated hydrochloric acid, the carbon is filtered
off, and the filtrate is evaporated to dryness, the hydrochloric acid being
in this way completely driven off. A small quantity of a very dilute
solution of hydrochloric acid is then used to damp the ash. The crystal-
line mass is then treated Avith kirkuma (a tincture of turmeric, prepared
according to Fresenius, Qualitative Analysis, 14th Edition, p. 90) and dried
in the water-bath. In the presence of even very small quantities of boracic
acid the dry substance exhibits a colour from cinnabar to a cherry-red.
The reaction is so delicate that even -001 to '002 per cent of boracic acid
can be easily detected in milk. An exact quantitative determination of
boracic acid in milk is not possible. The amount present can, however, be

88 SCIENCE AND PRACTICE OF DAIRYING.

approximately estimated if the addition is so considerable that the per-
centage of ash in the milk is increased above its ordinary amount.

Small quantities of benzoic acid are most easily and most certainly
detected by the following test (Meissl): — 250 to 500 c.c. of milk are
rendered alkaline by the addition of a few drops of lime or baryta water,
evaporated down to about a fourth of its volume, stirred into a paste
vath gypsum powder, pumice-stone j^oAvder, or sand, and then dried on the
watei'-bath. If condensed milk is to be investigated, 100 to 150 grams of
the milk may be treated directly with gypsum and a few drops of baryta-
water. The dry mass is then powdered, moistened with dilute sulphuric
acid, treated four times in the cold with about twice its volume of a
50-i)er-cent alcohol solution, which easily dissolves benzoic acid, and which
has little or no action on fat. The alcohol Avashings, which show an acid
reaction, and which contain in addition to benzoic acid, milk-sugar and
inorganic salts, are then mixed, neutralized with baryta - water, and
evaporated down to a small volume. This residue is rendered acid with
dilute sulphuric acid, and finally is shaken up with small quantities of
ether. On diluting the ether, benzoic acid is left behind in an almost
pure condition. If not pvire, it only contains traces of fat or ash con-
stituents. For quantitative determination it is dried at 60° C. in the
desiccator, weighed, the benzoic acid is sublimed, and the residue is again
weighed. Sublimation is best effected on the water-bath, and is best
carried on in such a Avay that the small basin containing the substance
is covered with another basin of similar size, or Avith a Avatch-glass. The
sublimate on the little basin lying on the top may be used for qualitative
test, Avhile the loAver basin is heated uncovered for some time until all the
A'olatile substances are expelled. The qualitative reaction for benzoic
acid, AA'^hich is the most striking, is its reaction Avith neutral iron chloride;
the substance dissolved in Avater must, hoAvever, be treated Avith a feAV
drops of sodium acetate.

Boiled milk may be detected from unboiled milk, in addition to the
flavour test, by the ozone reaction, AA-hich unboiled milk gives but boiled
milk does not. Unboiled milk colours guaiacum tincture blue, boiled milk
does not. Potassium iodide starch-paper with oil of turpentine is quickly
coloured blue by unboiled milk. Boiled milk does not exhibit this reaction,
or at any rate no more quickly than the mixture itself becomes blue. The
detection of starch in milk offers no difficulty. If starch has been added
to cold milk, it settles on the milk being left standing, and can be easily
collected in the bottom of the vessel. In order to detect the presence of
boiled starch in milk, a large quantity of an iodine solution is necessary,
since a considerable quantity of iodine is required to saturate the albumin-
oids before the iodine reaction is exhibited.

CHAPTER III.

MILK IN ITS RELATION TO MICRO-ORGANISMS. — DAIRYING AND
BACTERIOLOGr.

36. The Bearing of Bacteriological Research on Dairying. — Lon^
before it was known that all fermentation and decomposition were
caused by micro-organisms, the practice of dairying prescribed the
greatest cleanliness in the treatment of milk and the great im-
portance of always providing good pure air in all dairies; it showed
the danger of exceeding a certain temperature, and recommended in
cheese-making a careful regulation of the percentage of moisture in
the cheese. The real reasons of these precautions were not known
at that time, but experience taught that their observance was the
best security against certain injuries to which dairy products were
liable. We now know that uncleanliness leads to a raj^id development
of all micro-organisms, that musty stagnant air is heavily laden
with spores of fungi and bacteria, that the activity of growth of
these small organisms is influenced by the temperature, and that in
general the damper and softer the fermenting mass is, the more
rapidly does the development of fermentation take place. It is a
fact that many bacteria which act as carriers of deadly infectious
diseases, or as the creators of poisonously acting substances, can live
in milk and render it poisonous. It has further been proved that
certain bacteria cause the so-called spontaneous coagulation of milk,
that others can exercise a disturbing influence on the creaming of
milk and on the preparation of butter, and that other micro-
organisms can cause the ripening of cheese in quite undesired wa^'s.
Just as, in dairy practice, it is desirable on the one hand to war
against dangerous or unfavourable processes caused by bacteria, so
on the other hand it is desirable to promote the action of certain
kinds of fission fungi. For example, some are not only absolutely
necessary for the process of cream souring, required in the pro-
duction of fine butter, but also for the inception and development
of the ripening processes to which the diflerent kinds of cheeses
owe their characteristic properties. The undisturbed and regular
development of dairy manufactures depends upon the successful

90 SCIENCE AND PRACTICE OF DAIRYING.

regulation of a large number of fermentation processes. Since the
technique of dairying is, as a matter of fact, dependent to a very-
large extent on ferments, which affect alike the distribution of milk
for direct consumption or its utilization for dairy products, the neces-
sity exists for everyone who takes an interest, either theoretically
or practically, in the domain of dairying, to make himself familiar
to a certain extent with bacteriology^ It is esi^ecially necessary for
the directors of agricultural experimental stations and laboratories to
make themselves familiar with the science of bacteriology generally,
and with the methods and details of the processes of investigation.
The gradual abolition of the uncertainty surrounding dairy manu-
factures is the present important duty which lies before us, and its
solution can only be effected by bacteriology. For this reason
bacteriological research is of the highest importance to dairying,
and it is this consideration which justifies our devoting a short
section to its discussion.

37. The Lower Fungi. — Although microscopical organisms, espe-
cially bacteria, were discovered in the year 1675 by the Dutchman
Leeuwenhoek, our knowledge of them was no further advanced.
No idea could then be formed of their enormous distribution in the
air, water, or soil, nor was it dreamt that they performed such an
important role with regard to human life. Indeed, they were long
regarded as harmless, and as f)erforming no functions in terres-
trial economy. Nevertheless it was observed that they occurred in
large numbers in all fermenting and decomposing bodies. This
phenomenon could be explained in two waj^s. The bacteria and
the other low forms of fungoid life could be the exciting cause of
fermentation and putrefaction, or, on the other hand, their presence
might have nothing directly to do with these processes, and they
might only be found in large numbers on such bodies because the
fermenting and putrefying bodies provided suitable conditions for
their development. In opposition to the vitalists, the supporters
of the first-mentioned view, it was sought to trace fermentation
and putrefaction to purely chemical and mechanical causes, espe-
cially to the oxygen in the atmosphere. At the end of the. sixth
decade of the present century a very interesting discussion took
place between Justus von Liebig, who supported the chemico-
mechauical theory of fermentation, and the vitalist, Pasteur. What
had already been asserted by Spallanzani, Cagnard-Latour, Schwann,
and others, with regard to tlie process of putrefaction, was soon

THE LOWER FUNGI.

proved by Pasteur by direct and unbiassed observations to V»e true
for the phenomena of fermentation, viz., that these processes were
effected by minute organisms of the class of bacteria, fungi, and
protozoa. When it was soon further proved that certain bactei*ia
must be regarded as the undoubted causes of different infectious

Fig. 27.— Different Forms of Bacteria.

a. Coccus; 6, diplococcus; c, streptococcus; d, staphylococcus; e, bacterium; /, bacillus;
^, spirillus; h, kladothrix; i, bacilli with ciliic; j, bacilli with spores; k, yeast-cells;
I, penicillium glaucum ; m, aspergillus (mycelium with conidium) ; n, mucor stolonifer
(I, mycelium bearing sporangia, sp; II, section through sporangium showing spores);
o, oidium lactis. All greatly enlarged. After Freundenreich (from the report for 1893 of
the Agricultural Experiment Station, University of Minnesota).

diseases, the full importance of the lower fungi in relation to health
and life became recognized, and the study of their nature became
of the highest interest. The micro-organisms, which are of the
greatest importance in dairying, as is the case with the majority of all

92 SCIENCE AND PRACTICE OF DAIRYING.

those smallest of li\iiig growths known under this name, belong to
the lower fungoid kind, which in their turn belong to the crypto-
gams. The lower fungi can be divided into fungi proper (moulds),
budding fungi (yeasts), and hssion fungi (bacteria). Their function
in nature is to set up in the lifeless higher organic bodies a con-
tinuous process of disintegi-ation and decomposition, and finally to
mineralize them — that is, to convert them into water, carbonic
acid, ammonia, nitric acid; in short, to change them into simple
inorganic compounds, from which the entire higher plant world
builds up its organic material.

According to the special phenomena w^hich occur in such de-
composition processes, according to the nature of the transition
products formed, and according to the nature of the organisms
which effect them, the process is called decomposition, putrefaction,
or fermentation. No decomposition can take place without the
presence of moulds or budding fungi. The characteristic putre-
factive processes are essentially caused by fission fungi, and in the
production of fermentation, budding fungi (beer and wine fermen-
tation), as also acetic, lactic, butyric, and urea ferments, also take
part. In the development of their special action the different kinds
of the lower fungi exhibit different striking phenomena. Some
yield colours, others cause phosphorescence, while others again
produce liquids in which grow thick and slimy chemical ferments
(enzymes), causing the production of odours and smells or the
production of substances, which exercise on human and animal life
an extremely poisonous action (ptomaines and toxalbumins). But
the action of the lower fungi is not limited to lifeless organic l)0 lies.
There are numberless kinds which are able to take possession of
living organisms, some of Avhich not merely exist in living plants
and animals or inside the human body, and as parasites feed upon
their hosts in exceptional cases, but there are others which threaten
them with degeneration and death.

The lower organisms possess interest for us in this connection
in a threefold manner. For example, they are quite indispensable
for the continuance of all living nature, inasmuch as they cause
putrefaction and decomposition of dead organic matter, and render
possible the development and the existence of the entire higher plant
and animal world. Of the greatest utility are those by whose action
the growth of certain kinds of our cultivated plants is assisted, and
those which act in the preparation of certain foods as bread and

DISTRIBUTION OF THE LOWER FUNGI. 93

cheese, as well as the universally appreciated beverages wine and
beer. Finally, they are not only deleterious, but also highly
dangerous when they act as destroyers of* the means of life, and as
the exciting causes of many fatal diseases.

38. Distribution of the Lower Fungi. — The number and distribu-
tion of the spores of the lower fungi of all kinds are quite enormous
in water, in the soil, and in the air. It is quite impossible, even
with the exercise of the greatest care and cleanliness, to prevent
cows'-milk, in the process of milking, — a process which takes
place in the presence of the air, — from coming into contact with the
hands of the milker and the milk vessels, and from thus absorbing
a very large number of the spores of the lower fungi. Now, as
milk, from the fact of its peculiar chemical composition, forms a
specially nutritive medium, and offers most favourable conditions
for the development of large numbers of budding and fission fungi,
the result is that the spores are not destroyed, but, on the contrary,
increased with very great rapiditj^ From a few spores in warnj
milk an incredible number of bacteria (from thousands to several
millions per cubic centimetre) may be developed in the course of a
few hours. It is obvious that milk which is strongly contaminated
with luxuriant and growing fission fungi must have its ordinary
dairying properties affected, and that its direct use may seriously
threaten the health of the consumer. Among; all the lower oro-anisms
which are of first importance in dairying are the bacteria, and for
this reason they deserve our special attention.

39. The Forms and Life Conditions of Bacteria. — By bacteria, in
the widest sense of the term, is understood all fission fungi. All
bacteria or fission fungi consist of simple cells which are divided
from one another, or are joined to one another in chains, bundles,
heaps, or occasionally in firm glutinous masses. According to their
form they are distinguished as follows: — The round, globular-shaped
ones are known as cocci, micrococci, macrococcl, and diplococc'i. The
straight staff-shaped are called bacilli, and the spiral-shaped ones
are known as sjnrilU and spii'ochdeti.

The conditions of development in which the cells exhibit active
growth is known as the vegetative, and the growing cells are the
vegetative cells. Growth always takes place in this way, that the
cells divide into two halves (by fission), from each of which anew
cell arises; hence the name, fission fungi. In addition, moreover,
many bacteria among the staff or spir.il formed kind possess the

94: SCIENCE AND PRACTICE OF DAIRYING.

power of growth in another way, viz., by shedding seed-like bodies,
the so-called spores, which, however, do not multiply as such. During
this process, as a rule, there can be seen in the inside of the vessels
themselves, brightly glittering bodies, chiefly pear-shaped, which sub-
sequently develop into spores. While the vegetative cells are easily
killed, the spores exhibit a high degree of resistance to unfavourable
external conditions. The sj^ores or the lasting cells, or lasting-
spores, as they are named, are cells which possess a thin but very
compact membrane. Under favourable conditions they germinate
and grow into a new and much larger vegetative form of fission
fungi.

The life of bacteria is to a great extent dependent on temperature.
With reference to this, every bacterium has a maximum and minimum,
even an optimum degree of temperature at which it flourishes, and
further, a point below or above which it dies. With reference to
the low death point, it may be remarked that the influence of cold,
especially repeated freezing and repeated thawing, according to
late researches, is able to destroy many kinds of bacteria. The
temperature above which death ensues lies, for the vegetative cells
of the majority of bacteria, between 50° and 60° C, while their
spores are able to withstand a much higher temperature. Most
spores remain capable of germination even after being heated for a
short time in liquids at lOO" C, and many resist for a comparatively
short time even a dry heat of 130° to 150° C.

These facts, which have been discovered by careful experiments
under reliable conditions, possess the greatest practical importance.
They teach that vegetative cells of almost all kinds of bacteria
present in liquids are certain to be destroyed by heating for a
comparatively long time (about two hours) at a temperature of 60°
to TO" C, and that a liquid may be rendered perfectly sterile, i.e.
free from resistant spores, if heated at 120° to 130° C, for a similar
period.

In addition to temperature, the life of the lower organisms is still
further influenced by the reaction and by the concentration, that is,
the percentage of water of the nourishing liquid or the nutrient
soil. Further, it is affected by the presence of bodies which exert
a deleterious action on the cells, by the free access or otherwise of
the oxygen of the atmosphere to the cells, and finally by electricity
and by light. The ferments proper prefer a slightly acid reaction
in their nutrient liquid or nutrient soil. The fission fungi, on the

STERILIZATION OF MILK. 95

other hand, prefer a slightly alkaline reaction. That dry oi'ganic
matter is less liable to decay than damp is well known, and also
that not only the products of the action of bacteria, but also many
other stuffs, such as alkalies, in a state of strong concentration,
carbolic acid, corrosive sublimate, chlorine, bromine, sulphurous acid,
&c., exert a poisonous action on the bacteria. Many bacteria, espe-
cially those of the aerobic sort, are only able to live in the presence
of a plentiful supply of free oxygen. Others, the anaerobic kind, on
the contrary, as Pasteur first pointed out, require, for their develop-
ment, the absence of free oxygen; while lastly there are others, the
facultative anaerobics, which can exist under both conditions.

40. Sterilization of Milk. — It has been known since the year
1884 that sterilized milk, to which no sugar had been added,
enclosed in hermetically-sealed tin vessels, has been known which
could be kept perfectly well, and without losing its value, for use
on board ship and for export to foreign countries. On the other
hand, the great advantages of sterilized milk as an article of food,
especially for the feeding of children, have not till recently been
recognized. Its preparation has been first rendered possible by the
work of Hueppe, and through the indefatigable, inventive, technical
genius of Soxhlet.

After what has been stated in § 39, the question presents
itself as the theoretically ver}^ simple one of destroying the low
organisms in milk. Were the question only the destruction of
vegetative cells, the continuous heating for 15 minutes at a tem-
perature of 75° C. would be sufficient. This treatment is known
as Pasteurizing. This is of exceptional importance for milk con-
taminated with pathogenic germs. The more important kinds of
this type of germ, viz., those causing tuberculosis, typhus, and
cholera, form, so far as present researches show, no lasting spores,
and succumb therefore to very low temperatures. In the case of
many spores of different kinds of saprophytic bacteria, however,
which often occur in milk, and which impair to a very large extent
its keeping properties, the only way to destroy these effectually
when they are present is by means of a comparatively high
temperature, either by simple or intermittent sterilization.

Milk is sterilized in the full sense of the term only when it has
been rendered entirely free from germ-life by sufficient heating, that
is to say, when all the lower forms of life which it contains, vegeta-
tive forms as well as lasting forms, are entirely killed, and any

96 SCIENCE AND PRACTICE OF DAIRYING.

enzymes formed by bacteria are destroyed. Perfect sterilization
can only be effected by submitting the milk to the action of
continuous heating for two hours at a temperature of 120^ C, or
for 30 minutes at a temperature of 130^ C, or when it is submitted
to intermittent heating at different high temperatures. The latter
method of treatment, the so-called intermittent sterilization, avoids
the heating of milk at temperatures over 100° C, and consists in
heating the milk for two hours at a time at a temperature of from
70° to 75° C, then keeping it for several days at a temperature
suitable for germ development, about 40° C, in order to permit
the spores which are left behind to germinate and to form vegetative
cells, then in order to destroy these to submit the milk for two
hours at a time to a temperature of 70° to 75° C, then again to
allow the milk to stand for several days at the same favourable
temperature, viz., 40° C. These consecutive changes of temperature
are repeated five times, one after the other, and at last the milk is
brought to a temperature of 100° C.

In the above-mentioned treatment of milk, however, its proper-
ties undergo considerable changes. Among these changes is the
conversion of its soluble lime salts into an insoluble condition. The
result is that the milk no longer forms, when treated with rennet, a
cohesive coagulation; while it coagulates under the action of acids in
a fine, flocculent form. As a further result of this treatment, the fine
condition of division of the milk-fat is somewhat altered. A large
number of the fatty globules of the milk come together, and after
a time there collects on the surface of the milk a cream which
resembles butter, and which can no longer be uniformly broken up.
Finally the milk assumes a dirty brown yellowish colour and a
strong taste of boiled milk. All these undesirable changes, which
affect the keeping properties of milk, take place in different cases
more or less markedl}^ according to the method of sterilization, most
markedly in the case where milk is heated for a longer period at
120° C, and least markedly in the case where it has been subjected
to intermittent sterilization. For this reason the latter method of
sterilization is to be preferred to all other methods of sterilization
Unfortunately, however, it is such an inconvenient method, and
requires so much time, that it is not well suited for general
application. No other course, therefore, is at present open than to
dispense with perfect sterilization, and to be content with milk
which has been temporarily sterilized.

STERILIZATION OF MILK. 97

Pathogenic — that is, disease-producing germs — as well as other
dairy microbes of most common occurrence in fermenting milk can
be destroyed by a steam heat of 68° to 75' C. for one hour's time, or
for three-fourths of that time when the temperature is 100° C.
This is so where the amount treated does not exceed one litre.
For this reason it is comparatively easy to effect the complete steril-
ization without any alteration of its chemical composition, its
colour, or the state of its fatty globules, provided the milk does not
contain spores of a resistant nature. Unfortunately such pure milk
rarely occurs in ordinary practice. Sterilization becomes very
difficult in the common case of milk which has been contaminated,
through dirty and careless handling, with very resistant spores,
such as some bacteria belonging to the species of butyric acid, and
hay and potato bacilli (for example, bacillus mesentericus, liodermus,
butyricus, and subtilis).

From what has been already said, it will be seen that milk is
sometimes easy and sometimes difficult to sterilize. Milk containing
lasting forms of the above-described nature may keep at ordinary
temperatures for about six months unchanged if previousl}' heated
for 45 minutes to the temperature of boiling water; yet at a
temperature favourable to the development of bacteria it may
coagulate, often with considerable development of gases, after only
three or four days. Where coagulation ensues, this is never effected
by the formation of acid, but always by enzymes formed by
bacteria, which are of the nature of rennet. It is in the highest
degree improbable, that lasting spores which have not been entirely
killed in milk treated according to Soxhlet's method and then
consumed should be able to germinate during the short, digestive
period and exercise a deleterious action, yet it is not absolutely
impossible. For this reason every effort should be made to effect
the perfect sterilization of milk. Temporary sterilization, which is
at present almost universally practised, would graduall}' become
improved and brought nearer to perfect sterilization if it were only
possible to obtain milk in ever-increasing quantities capable of
being easily sterilized. For this purpose nothing further is wanted
than cleanly handling of milk ; and thus avoiding its contamination
with such resistant spores of bacteria as above mentioned. How
simple this demand seems to be when stated, and yet how extraor-
dinarily difficult it is in practice to have proper attention paid to it!

Hueppe recommends that all milk destined for the use of

98 SCIENCE AND PRACTICE OF DAIRYING.

children should, before sterilization, be submitted to the action of
the centrifugal separator, and the cream and the skim-milk separated
in this way should be collected in the same vessel. He asserts that
the most of the low organisms, and among them the most dangerous
of the lasting kinds, remain behind in the mud residue, and that
such treatment of milk renders it much more easy to sterilize.
Whether treatment in the centrifugal machine does liave this effect
on milk is very doubtful.

8oxhlet suggests that cows should only be fed with scalded or
steamed hay, in order in this way to prevent the contamination of
the milk with the spores of the hay bacillus.

Although it may be admitted that perfect sterilization is not
effected by the widely-known Soxhlet method of the treatment of
milk, nevertheless it can be asserted that it, and the milk steriliza-
tion apparatus also designed for household purposes by Soxhlet,
have proved themselves extremely useful. In the wide-spread
application which the apparatus has met with it has proved itself
eminently successful, inasmuch as it has undoubtedly contributed
very materially to a diniinution of the rate of mortality in children.
Hueppe recognizes this, but regards the sterilization of milk in
single households as only a makeshift, and he would regard it as a
distinct improvement if the sterilization of milk could be accom-
plished in small bottles, either at the place where it is produced,
that is, in the larger farms in the neighbourhood of towns, or in
large municipal institutions. Only under such conditions would it
become easy, he thinks, to gradually effect the sterilization of milk
in large quantities.

In the first place it is in the interests of the management of the
farm to pay the most careful attention to the cleanly treatment of
milk, and in the second place, before sterilizing, the milk should be
cleansed or purified in the centrifugal machine. Milk, according to
Hueppe, is best sterilized on the spot where it is produced, by
pouring it immediately after milking into half-litre bottles and
exposing it in these for 45 minutes to a steam heat of 100° C.

In the Dresden dairy of Pfund the milk to be sterilized is first
heated to 60° C, thereafter it is poured into the patent bottles, and
these, after they have been closed, are heated in the steam apparatus
for some time at 100° C Milk intended for the nourishment of
children is first treated in a centrifugal apparatus.

Milk which is temporarily sterilized, or, in the most favourable

COAGULATION OF MILK AND SOURING OF CREAM. 99

cases, perfectly sterilized, has been recently called permanent milk.
In its preparation different kinds of steaming apparatus are in use,
among them that of Neuhaus, Gronwald, and (Ehlmann is very
popular. This apparatus renders it possible during heating to expel
the air from the milk and the bottle, and after the heating has
been finished to close the patent bottles by means of a lever in the
apparatus itself before its cover is removed.

41. The Spontaneous Coagulation of Milk and the Souring of
Cream. — The so-called spontaneous coagulation of milk takes place,
as has been already explained in § 7, as soon as a certain quantity
of lactic acid is formed by lactic fermentation. The amount of
lactic acid produced depends on the original condition of the milk,
and the quantity of ferments present. It is dependent also on
the temperature. It has been already noticed that there are a
compai'atively large number of forms of genuine lactic bacteria very
similar to one another both in their form and properties, which
together are able to effect the formation of lactic acid and the spon-
taneous coagulation of milk. Some, and this especially applies to
the bacillus acidi lactis of Hueppe, split up the molecule of milk-
sugar with comparative ease into four molecules of lactic acid, and
produce at the same time an extremely slight evolution of carbonic
acid. Others produce small quantities of secondary bj'e-products,
especially alcohol, and others, again, develop in addition very minute
quantities of odorous bodies, regarding which very little else is
known. Various indications, as has been pointed out, show that
in the spontaneous coagulation of milk the caseous matter does not
seem to remain unchanged, as is the case in the artificial precipita-
tion by addition of acids, but undergoes slight changes.

The most important practical application of lactic fermentation
is seen in the souring of cream for the manufacture of butter, an
operation which takes place every day in dairies. Bacteriology has
already annexed this operation as a suitable field for investigation.
Ever since it has been shown to be probable that all kinds of lactic
bacilli are not equally well adapted to act as ferments in effecting
this change, the attempt has been made to isolate and to cultivate in
pure cultures the particular varieties which are believed to produce
the best butter with the finest aroma. In order that this may be
accomplished, it is necessary to describe exactly how a fresh and
pure daily supply of the souring liquid, or, as it is called, the acid
generator, is obtained. It has been recommended to infect with a

100 SCIENCE AND PRACTICE OF DAIRYING.

pure culture of the bacilli in question a sufficient quantity of fresh
skim-milk which has been once, or oftener, heated to 70° C, and
then cooled to the temperature required for souring, viz., about
16° C, then to allow it to become sour, and when this has been
accomplished to use it as a souring agent. The cream to be soured
may be previously Pasteurized, and, it is hardly necessary to men-
tion, should be carefully protected from contamination. The daily
employment of pure cultures of lactic ferment for cream souring
can scarcely be expected to come soon into regular practice, and no
wide-spread demand appears to exist for them as yet. On the
other hand, in course of time such pure cultures will probably
come to be used more and more, and the more so as it becomes
better understood that undesirable properties in butter have pro-
bably their origin in the improper souring of the cream.

42. Different Kinds of so-called Milk Diseases (Milch -fehler). —
Occasionallj' it happens that milk or cream coagulates without any
previous lactic fermentation. For example, we need onlj' cite the
coagulation of boiled milk, in which the reaction is neutral, and
the cheesy appearance assumed by cream, in which the precipitation
of caseous matter is certainly not effected by lactic acid. The co-
agulation of milk of neutral reaction, spoken of b}' some as sweet-
milk coagulation, is effected by means of different kinds of bacteria,
which Duclaux has grouped under the name tyrothrix. These
fission fungi, which for the most part belong to the group of the
so-called potato bacilli, give rise to enzymes of the nature of rennet,
which precipitate the caseous matter in milk possessing a neutral or
even a slightly alkaline reaction, and which in time dissolve more
or less perfectly the coagulated mass. If milk which has been
repeatedly boiled does gradually coagulate, and this while showing
an almost entirely neutral reaction, such a condition points to the
presence of bacteria of this class, whose lasting spores have been
enabled to withstand the boiling temperature which has destroyed
the lactic bacilli.

Many disturbances of milk, which occur in creaming and in the
preparation of butter, and the causes of which were formerly sought
for in disease of the cows, in the influence of weather, and espe-
cially in the physiological action of certain foods, that is, in quite
erroneous causes, have now, through bacteriological investigation,
been certainly traced to fission fungi.

Where premature or unusuallj'' rapid coagulation occurs, there

DIFFERENT KINDS OF SO-CALLED MILK DISEASES. 101

can be no doubt that the milk contains an extraordinary quantit}''
of luxuriantly-growing lactic bacilli. If milk during creaming be-
comes fermented, or during the manufacture of cheese yields puffy
cheese, all these indications point assuredly to the presence of a
large quantity of a certain kind of fission fungi, and possibly also
of budding fungi.

The mystery which formerly surrounded certain changes in milk,
by which it was rendered slimy or ropy, has to a certain extent been
cleared up. It has now been proved that the viscous consistency of
such milk has been caused either through a slimj^ body produced by
the decomposition of the milk-sugar, or is due to the fact that the
milk contains masses of bacteria, chiefly cocci, in the form of zoogloa
bacteria, the cell membrane of which has experienced a peculiar
change, associated with a large amount of swelling. In the first
case, certain micrococci produce from the milk-sugar a slimy sub-
stance, about which ver\' little is known, and also small amounts of
carbonic acid, and occasionally also mannite. In the second case it
would appear that no decomposition of the organic constituents of
the milk seems to take place by the action of the luxuriantly-
growing slimy masses of bacteria. Different kinds of bacteria
impart to milk an unpleasant, bitter, slightly rancid, and disagree-
able flavour, by either causing the production of butyric acid, and
perhaps also formic acid, or by separating peculiar bitter extractive
substances.

Formerly it often occurred that on the surface of milk set for
cream, coloured patches, red, yellow, or especially blue, were after a
time developed; or that the entire mass of the milk assumed a similar
unusual colour. These phenomena are also caused by the action of
fission fungi, viz. colour-producing bacteria. At present only one
kind of bacteria is known which can colour milk blue and one
which can colour it yellow, viz. the bacillus cyanogenus and the
hacillus synxanthas, which are known in several varieties, and
which live in symbiosis, that is, live together with other kinds of
fission fungi. On the other hand, there are many kinds of bacteria,
chiefl}^ lielonging to the group of micrococci, which impart a red
colour to the surface of milk or cream. The most of these bacteria
do not exert a decomposing action on the organic constituents of
milk. The widely distributed micrococcus 'prodigiosus, which
under certain conditions produces blood-red patches on the surface
of milk, on the contrary eflfects, in the first instance, a decomposition

102 SCIEXCE AND PRACTICE OF DAIRYING.

of the caseous matter, and subsequently redissolves a portion of the
coagulated mass, leaving in addition in the milk the unpleasant
flavour of herring-pickle (trimethylamine). Bacteria lactis ery-
throgenes coagulates the milk and imparts to it, if light be excluded,
a uniform blood-red colour; and a kind of sarcina produces a
brown-red colour in the milk.

In feeding with milk which is infected with colour-producing
bacteria, no deleterious action has yet been observed to be produced.
Such bacteria seem, therefore, not to exert a deleterious action on
the animal bodj'. It is obvious that all the influences due to
fission fungi, which exert a disturbing effect on dairj- practice, can
be imparted by means of the organisms and the spores from one
mass of milk to another, that is to say, they are infectious. For this
reason, the only way of curing them where they exist is by the
destruction of the respective fission fungi.

It is often very difficult to remove effectively the disease germs
present in milk, since the conditions of breeding favourable to the
organisms in the milk are not known, and also because almost
nothing is known of the development of the individual fission fungi.

43, Micro-organisms in Cheese. — That the ripening of cheese is
connected with and influenced by micro-organisms, and is successful
or the reverse, according to the nature of the organisms that are pre-
sent in predominating amount, is beyond doubt. Since it has been
proved that the organisms which are present in the cheese from the
first are largely developed during the ripening period, and since the
rij)ening will not take place wlien certain substances which are fatal
to germ-life are introduced, although these may not have any in-
fluence on the albuminoids of milk, or when fresh cheese is protected
fi'om the action of air, it follows that it is the low micro-organisms
which effect the ripening in all cheese. Since all the different kinds
of micro-organisms produce definite effects, it further follows that
each individual cheese requires for its ripening a special kind of
micro-organism. As our knowledge of the use of different kinds of
micro-organisms — for producing the many different kinds of cheeses,
and without which the specially desix'ed effects of the ripening are
not obtainable — increases, the great uncertainty which at present
prevails in the manufacture of cheese will gradually vanish. But
the application of a knowledge of the specific action of the various
micro-organisms to the manufacture of cheeses is not easy, and we
can scarcely hope to see it soon successfully eflfected. The subject is

MICRO-ORGANISMS IN CHEESE. 103

a very complicated one, from the fact that the proper ripening of
cheese is the result of the co-operation of different kinds of uncro-
organisms: a symbiosis or metabiosis in which certain kinds of
bacteria partly favour and partly retard the simultaneous develop-
ment in the same medium of other kinds of bacteria, or in which
one kind first pi-epares the way for and renders possible, to a certain
extent, the action of another kind.

As has been already pointed out, there are fission fungi which
produce peculiar ferments, which exercise a solvent effect on the
coagulated caseous matter. Probably no kind of cheese can do with-
out the action of these fungi for its ripening, by means of which the
original white and friable or fragile cheese is converted into a yellow-
coloured, soft, pasty mass. For all cheeses which are soft, and which
have a tendency to become liquid, the fission fungi are without doubt
of first importance. In the ripening of some cheeses, for example
Roquefort, Gorgonzola, Brie, Stilton, &c., certain fungoid organisms
cannot be dispensed with, since they, as has been explained, check
the action of the lactic bacteria, and gi-adually diminish the acid
reaction of the mass to such an extent that the bacteria which pro-
duce the decomposition of the albumin are permitted to develop.

Long before bacteriological investigation had thrown light on
the subject, practice had instinctively sought the help of fungoid
organisms for producing certain peculiar characteristics of certain
cheeses. In the preparation of Roquefort cheese, for example, the
cheese-makers were in the habit of mixing the fresh cheese with
fungoid organisms, and in the preparation of other kinds of cheese
they had endeavoured so to arrange the treatment of the cheese that
the colonizing and development of fungoid growths should take place
as quickly as possible on its surface and in its inside. On the other
hand, in the ripening of other kinds of cheese, the action of the
albuminoid destroying bacteria has been held in check by the lactic
bacteria, since the cheese would otherwise be liable to premature
decay.

In Holland, in the preparation of the Edam cheese, practice has
likewise preceded theory. In that country, when milk which has to
be used for churning is treated with sour milk, there is added to it,
if not a pure cultivation, j-et one in which the growth of colonies
of such bacteria (cocci) predominates, as experience has shown these
cannot be dispensed with in the ripening period.

In all ripened cheeses the presence of butyric acid can be

104 SCIENCE AND PRACTICE OF DAIRYING.

detected, sometimes in larger and sometimes in smaller quantities.
It is without doubt formed directly from milk-sugar by butyric acid
fermentation. It is indirectly formed for the most part from otlier
substances, which vary according to the kind of cheese and the kind
of organism active in the ripening process. Such substances are
hydrated milk-sugar, salts of lactic acid, albuminous bodies of milk,
milk-fat, or glycerine, formed in the saponification of milk-fat.

The organisms which interfere with the processes of ripening,
and which influence the products of ripening, have also been inves-
tigated. A very objectionable, and, at the same time, very commonly
occurring disturbance is the inflation of cheese. Many kinds of
lower organisms are already known which, under certain conditions,
are able to excite a kind of fermentation in ripening cheeses which
is associated with a strong evolution of gaseous bodies. Such are
the various kinds of onicrococci, the saccharomyces lactis, the yeast
discovered by Duclaux, and other kinds of yeast, tyrothrix uro-
cephalum, the onasticis cocci, bacterium lactis aerogenes, bacterium
coli commune, ?iXi^ others. In cheeses, on the surface or inside of whicli
red patches are developed, the presence of moulds, which in the con-
dition of sporulating produce a brick-red colour, have been detected,
as well as several kinds of micrococci, and also very probably a kind
of torula. A peculiar kind of disease cheese is subject to, in which
it becomes blue, has been probably traced to a kind of bacteria
which only flourishes in the absence of air (de Vries); while the
production on parts of the surface of cheese of black patches which
easily become sticky have been traced also to several diflerent kinds
of fungoid growth.

44. Characteristics of Milk which Owe their Origin to Micro-
organisms.— That milk which has been standing for some time
owes its peculiar properties to bacteria, is known, although little
is known as yet regarding their nature. In a similar way the
organic ferments which yield the purest and best koumiss still
await investigation.

Kephir, a slightly effervescing spirituous beverage, prepared
from milk, contains the common chief constituents of milk in a
slightly altered condition, in addition to minute quantities of car-
bonic acid, lactic acid, alcohol, and peptones. It also contains
caseous matter in a firm but very finely divided condition, well
known as kephir grains. In tliis beverage, several different kinds
of yeasts and bacteria have been identified. The yeasts differ from

DESTRUCTION OF MICRO-ORGANISMS. 105

the common beer yeasts, and are not able alone to cause the fermen-
tation of milk-sugar. This can only take place after the milk-sugar
has been dehydrated by the bacteria present in the kephir grains.
These bacteria act in different ways, some being able to induce
lactic fermentation, others to dehydrate the milk-sugar in presence
of certain yeasts, and others to partly peptonize the caseous matter.

45. Destruction of Micro-organisms. — In conclusion we may say
a word or two on the methods of destroying the microscopic enemies
of dairying, and the methods of effecting complete cleansing of milk-
vessels and the disinfecting of dairy rooms. For cleansing of vessels
of all kinds, different materials may be used according to their
nature, such as steaming under pressure, treating with hot strong
alkali solutions, preferably boiling soda solutions, or solutions in
which burnt lime has been dissolved. The disinfection of rooms or
spaces can be effected by covering the walls and ceilings with freshly
prepared milk of lime, or with a solution consisting of calcium
sulphate, and sprinkling the floor with an alkaline solution. Bad
flooring should be thoroughly repaired or entirely renewed. In
order to clean the hands one should wash them over with black
soap or a solution of creasote. Poisonous disinfectants, such as
mercuric chloride (corrosive sublimate) ought not to be used in
dairying.

46. The Practical Application of Bacteriology. — From the above
statements it may be safely asserted that dairying has already much
for which to thank bacteriological investigation. Bacteriology has
drawn our attention to the existence of a large number of well
ascertained and valuable facts that have new and highly important
and practical bearings on dairy practice. It has shown that dairying
must reckon in practice with small, and, so far as the naked eye is
concerned, invisible friends and foes. It has further taught the
desirability of sterilizing and Pasteurizing milk and its liquid by-
products, and in this way has conferred great benefits — benefits
which are not half sufficiently recognized — by showing the import-
ance of such treatment, not merely from the physiological and
sanitary point of view, but also in the technical interests of dairy
manufactures. It has further discovered the true causes of many
troublesome disturbances or diseases of milk, and has already pointed
the way, in at least a large degree, to their cure. Finally, it has
opened a prospect of the possibility of successfully combating tuber-
culosis in cattle.

CHAPTER IV.

THE MANUFACTURE OF BUTTER.

47. The Different Methods in which Butter is Made. — Butter is
the most important product of milk. As usually manufactured,
fresh butter contains about 83 to 84 per cent of milk-fat, 14 to 15
per cent of water, and 1'2 to 2"2 per cent of the other constituents
of milk. The percentage of the single chief constituents of the non-
fatty total solids of butter, if not exactly, is approximately the same
as in milk. Hitherto it has not been possible to obtain, in the form
of butter, all the fat which any quantity of milk contains.

In the preparation of butter the object aimed at is to solidify
the largest possible number of fatty globules in the milk, and then
to incorporate them. This has been hitherto, and still is effected,
by churning, which consists in shaking violently the fatty glo-
bules, and by this violent motion bringing them into intimate con-
tact with one another. Although butter can be obtained by direct
churning of the milk, an easier and preferable way is to collect
the larger portion of the fatty globules by allowing the milk to
be divided into two layers, the top layer, which contains as much
fat as possible, constituting the cream, and the lower layer, the skim
milk, which may be live to six times deeper than the top layer,
and contains the least possible amount of fat. The skim milk is
separated and the cream is churned. This separation was effected
up to the year 1877 by setting the milk in suitable vessels so as to
permit it to collect. It was left for from 12 to 48 hours, and even
longer, until the greater part of the fatty globules, owing to their
light specific gravity, collected on the top, and formed a layer easily
recognizable by the eye. In this way the milk was divided by a
sharp line into two layers, the skim milk and the cream. Since the
year 1877 centrifugal force has been employed for the separation of
cream from milk, and the use of this method has extended every
year since. There are thus two methods of obtaining cream, the
old and the new.

It is perhaps not superfluous to notice that cream and butter are not

lOG

THE OLD METHOD OF CREAM-SEPAKATION. 107

the same as milk -fat or butter -fat. It is not correct to speak of the
percentage of cream or butter in milk, since cream and bvitter are not
milk constituents, but milk products.

48. The Old Method of Cream - separation — Cream - raising. —
According to the formula given in § 6, it is easy to calculate the
acceleration which drives the fatty globules of the milk to the
surface (not taking into account any opposing forces) to be about
120 centimetres, or the eighth part of the acceleration of free-falling
bodies. The fatty globules in milk would, therefore, in the tirst
second of their movement, were it not for the friction due to their
movement, traverse 60 centimetres. Consequently, in layers of
milk not deeper than 60 centimetres the fat globules should be
collected on the surface in about a second's time. That this does not
actually take place, in point of fact, in cream-raising, is due to the
friction, which is exceedingly great in the case of the extremely
minute fatty globules. The ease with which single fatty globules
overcome resistance of different kinds is dependent solely on their
size. The large globules, of which some weigh 244 times more
than the smallest, overcome this resistance very easily, for they
come to the top in a deep milk layer very quickly, some of them
certainly in less than a minute. This is the case in warm fresh
milk. The smallest, on the other hand, are unable to overcome
this resistance and no longer exhibit independent motion, but follow
the milk-serum wherever it carries them. The rate at which the
globules tend to come to the surface depends directly on their
size. Were all the remaining constituents of milk in a state of
solutioii, the rising of the cream would take place with compara-
tive ease, since the fatty globules would only have to overcome the
internal friction and resistance which their motion entailed, and
the resistance offered by the currents caused by .their movements
in the serum. But further opposition is experienced by them
through the fact that the caseous matter, and possibly also some
of the mineral salts of the milk, are not in a state of solution, but
are in a precipitated condition. We call the state of precipitation
perfect when it offers compai'atively little resistance to the motion
of the fatty globules, and imperfect when it offers, on the other
hand, a large amount. Generally speaking, it may be said that the
state of precipitation of the caseous matter is most perfect in fresh
milk, and becomes gradually less so in the course of about three

108 SCIENCE AND PRACTICE OF DAIRYING.

hours, even although the surrounding conditions are exactly the same.
It is fui'ther known that, with an increasing percentage of lactic
acid in milk up to the point of spontaneous coagulation, the precipi-
tation of the caseous matter becomes more and more imperfect.
It is also known that it is not the same in samples of milk of
different origin, and that it is sometimes more perfect and some-
times less perfect, according to the exact composition of the mineral
salts of the milk. The fatty globules, in their motion, have to push
aside or push through the coagulated masses of serum. It follows
from the nature of the molecular forces coming into play in this
connection, that the resistance offered by the different causes
mentioned diminishes with the rise of temperature and increases
with the lowering of temperature, and also that the condition of
the precipitation of the caseous matter is more perfect the higher
the temperature. The resistance above referred to is only to be
reckoned with in the case when the milk-serum is at perfect rest
during creaming, or when, at any rate, no vertical current move-
ments exist in the milk. It is difficult, however, to prevent currents
arising in creaming operations, due to cooling. The colder portion
of the milk, being of greater specific gravity, sinks to the bottom,
and the warmer portion, being lighter, rises to the top. In this way
the collection of fatty globules on the surface is disturbed and
impeded. The descending currents carry away more fat with them
from the cream layer than the ascending currents bring back to
the surface. It is only after the entire mass of the milk assumes
the same temperature as the surrounding air, and when no further
changes owing to temperature are induced, that the fatty globules
can follow without disturbance their tendency to collect on the
surface. For creaming the following conditions are necessary: —

(1) Milk should be set immediately after milking, since the con-
ditions of coagulation of the caseous matter are then most perfect.

(2) Cream-raising ought to be carried on at the highest possible
temperature, in order to avoid, as much as possible, the resistance
the fatty globules meet with in coming to the top.

(3) The milk of large and well-fed cows should preferably be
used, since it is very probable that such milk will possess the usual
properties of milk, and especially will undergo a proper coagulation
of the caseous matter,

(4) The progress of lactic fermentation, which unfavourably
influences the coagulation of the caseous matter, should be retarded

THE OLD METHOD OF CREAM-SEPARATION. 109

by all available means, such as cooling the milk to a low tempera-
ture, the observance of the greatest cleanliness in handling the milk,
as well as in the rooms where cream-raising is carried out, and by
taking care that only pure dr}^ air should be provided in these rooms,
and that they should be properly ventilated.

(5) The currents induced in milk by cooling, especially those
moving in a perf)endicular direction, should be prevented, or should
be reduced to the shortest possible duration.

The extent to which these requirements are carried out will
depend on the amount of fat obtained in a given time from the la3^er
of cream, and the success of the cream-raising. The requirements
which demand that the milk, on the one hand, should be kept as
warm as possible in order to minimize the amount of resistance,
and those, on the other hand, which demand that the milk should
be kept as cool as possible in order to lessen lactic fermentation,
are contradictory to one another. Since, however, the second
requirement is undoubtedly of greater importance than the first,
there is no option but to fix the temperature of cream -raising so
low that the milk will keep sweet — i.e. that on boiling it will not
coagulate — at least thirty-six hours. Practice has long demonstrated
that this is the case with a temperature of 12°, or at the most 15° C,
provided all precautions as to cleanliness have been observed. This
is, therefore, the temperature to be recommended.

Formerly there was a comparatively large number of difierent
methods of cream-raising in use, each one of which possessed special
advantages of its own. The most widely used and the most per-
fectly developed was that known as the Holstein method, which
originated in Schleswig-Holstein. Now, with hardly an exception,
all these methods have become antiquated, and are no longer used in
the larger new dairies. All the older methods of cream-raising are
at one in requiring that the greatest cleanliness should be observed,
and that the milk should be set immediately after milking. They
all, including the Swartz and Devonshire methods, prescribe also
a certain temperature to which the milk, as it comes from the cow,
has to be cooled, and require that milk should be maintained in the
further stages of the process at the cream-raising temperature. In
other respects they show considerable differences in respect of the
temperature to which the milk is raised, the greater or less speed
with which the warm milk is cooled to the cream-raising tempera-
ture, and the method in which the cooled milk is maintained kt the

110 SCIENCE AND PRACTICE OF DAIRYING.

equable creaming temperature. The time occupied in cream-raising,
the form and the material of the vessels used in the cream-raising,
the depth of the milk-layer in the vessel, the rules laid down with
regard to the condition of the room in which the cream-raising is
carried on, and the method in which the cream is removed, also vary
according to the method adopted. In all methods of cream-raising
the milk possesses an equable temperature during only a portion of
the entire cream-raising period. During the first hours, that is,
until it has been gradually cooled down to the prescribed tempera-
ture, milk creams at a comparatively higher temperature, since
the resistance offered to the fatty globules is comparatively less.
The creaming temperature is, therefore, the lowest temperature to
which milk is cooled down, and at which milk is sought to be kept.
It varies in the different methods of cream-raising here considered
between 9' and 24' C.

The more particular conditions under which the coagulation of
the caseous matter is unfavourable for creaming have been already
dealt with in § 21, when discussing milk which creams with
difficulty.

It is always a disadvantage if the highly favourable conditions
which exist during the first hours after milking are not utilized for
creaming. Experience has taught that milk which has been kept
for some time after milkinfj and has been cooled, or asfain disturbed,
or left temporarily quiet, and again disturbed, always yields a less
satisfactory quantity of cream than milk derived from the same
source which is at once set after milking.

That the slightest disturbance of milk during cream-raising
exercises an appreciable influence on the collection of fat in the
cream can be easily understood when we remember the compara-
tively small quantity of fat globules distributed throughout the
milk. For this reason, it is only natural that under like conditions,
the less milk is disturbed, the greater the quantity of fat obtained in
the cream. The collection of fat on the surface of milk at first
takes place very rapidly, and diminishes the longer it proceeds. Even
when the cream-layer which has been formed is no longer increased,
its percentage of fat nevertheless continues to increase steadily as
long as the creaming continues. For this reason, in every method
of cream-raising, there is a certain period of time, the so-called
cream-raising time, at the conclusion of which the cream is removed,
since the increase in the percentage of fat in the cream after this

THE OLD METHOD OF CREAM-SEPARATION. Ill

takes place so slowly that it is no longer worth while to let the
milk stand.

The sooner the vertical currents, due to the cooling of the milk,
cease, and the fatty globules are enabled to exercise their tendency
to rise to the surface without hindrance, the more successfully will
the process of cream-raising be carried on. If metal vessels are
used in cream-raising, and care is taken that the milk is cooled by
the application of cold to the sides and bottom of the vessel, vertical
currents may be altogether avoided, and creaming may be permitted
to take place under the most favourable possible circumstances.

There are no substances which, when added to milk, hasten the
process of creaming, and if chemicals are added to milk for the
purpose of retarding premature coagulation, such treatment is liable
to be regarded in the light of adulteration.

In the case of comparatively high equable temperatures — from
10" C. upwards — the collection of cream takes place by the formation
of a comparatively small layer of cream at first, which is gradually
increased. The fatty globules collect in the cream-layer according
to their size, the largest globules coming to the surface first, and the
smaller ones less quickly. In the case of lower equable tempera-
tures— 10° C. and downwards — the milk-serum is comparatively
viscous, and in consequence the fatty globules experience in their
movement greater internal friction. As long as the fatty globules
in cream-raising are not brought into close contact with one another,
they find their way to the surface undisturbed, more or less quickly,
without reference to their size. In a short time, however, it is
impossible for the larger globules to overtake unhindered the smaller
ones. Blocks occur in the ever-increasing swarm of upward-striving
globules, and there is seen, as a rule, after a longer time, a com-
paratively thick layer of cream, which, owing to the fact that the
fatty globules are slowly pressing up on one another, gradually
becomes more concentrated.

The lower the temperature at the end of the creaming period,
the greater is the expansion, weight, and amount of water in the
cream-layer, and the smaller is the percentage of its fat, after the
lapse of a certain time and in the case of a fixed degree of tempera-
ture. On the other hand, if milk of similar composition and under
similar conditions be set for creaming, the higher the creaming
temperature the less will be the cream, and that cream will contain
less water and correspondingly more fat, besides being more viscous.

112 SCIENCE AND PRACTICE OF DAIRYING.

The higher and narrower the vessels used for cream-raising are,
the deeper and less compact will be the layer of cream, and the less
will be the percentage, that is, the absolute percentage of the fat of
the cream under otherwise like conditions.

As will be seen, the thickness of the layer of cream depends on
certain particular conditions under which creaming takes place to a
greater extent than on the percentage of fat in the milk. It may
happen, as a general rule, that milk richer in fat yields under exactly
similar treatment a deeper layer of cream than milk poorer in fat;
but this is not always the case, and if milk richer in fat throws up
more cream, the depth of the cream-layer of milk from different
sources is seldom exactly proportional to the percentage of fat it
contains. Conclusions as to the percentage of fat in milk, derived
from the depth of the cream-layer, or the amount of fat which
creaming yields, are for this reason highly unreliable.

49. The Older Methods of Cream-raising. — Under the older
methods of cream-raising, the best known are the Holstein, Gus-
sander, Swartz, and Reimer methods. Other methods of cream-
raising, which have scarcely been attempted in Germany at all, but
which have been adopted in other countries, and to which references
are often met with in the literature of the subject, are the Dutch,
Devonshire, Orange County, Cooley, and the American clotted-cream
method. Among these different methods, the only one which is in use
at the present day in Germany in the larger dairies is the Swartz
method, and a slight variation of this method, viz. the cold water
method — where the conditions necessary for its utilization are present.
The remaining methods of cream-raising which have not altogether
died out, viz. the Holstein and the Satten (similar to the Holstein)
methods, are no longer suited for present requirements and may
well be described as antiquated. The Swartz method will be
described in the succeeding paragraph.

The methods of creaming Avhich are now obsolete may be enumerated
as follows: — ^Holstein (and the Destinon, which is a modification of the
Holstein method), the Gussander, the Reimer, the Dutch, the Orange
County, the American method of mass-creaming, the Cooley, the Devon-
shire, the Pommritz, the Xatron, the Tremser, the Becker, the Hacks, the
Kellog, the Electrical, the Speedwell, and the Kalma.

The separation of the cream from the skim-milk is effected either
by skimming the milk, or by allowing the skim-milk to flow carefully

THE OLDER METHODS OF CREAM-RAISING. 113

away from under the cream. For many reasons the former method
is to be preferred.

50. The Swartz Method of Cream-raising, — This method, devised
in 18G3 by Gustav Swartz, of Hofgaarden, near Wadstena, in Sweden,
requires an area of creaming space per cow of as much as half a
square metre, so that there is an excessive demand for creaming
space. It is directed in this method that the milk be poured into
special vessels, known as the Swartz milk-pans. These are long
four-cornered tin vessels, with rounded edges 50 centimetres high,
and of a capacity of 36 to 50 litres. The milk is poured in to a
depth of 40 centimetres. The milk-pans when thus filled are placed
in a long square receptacle, which is made of sufiicient size to hold
at least six or at most ten cans. They are then packed with ice
and left standing from 12 to at longest 24 hours. During this time
the milk is cooled down to within a few degrees of freezing point.
Swartz recommended that the sweet cream should be immediately
churned, and he thus gave an impetus in Sweden and Denmark
to the first attempt to introduce sweet-cream churning on a large
scale, and to place upon the world's market sweet-cream butter
(fresh butter) as a keeping butter.

A.S soon as the warm milk is placed in ice all vertical currents
cease, since cooling takes place chiefly on the bottom and sides of the
milk-cans, and not from above. Only currents flowing in almost a
horizontal direction, from the outside to the inside and vice versa,
take place, which, so long as the milk-can is not broader than say 16
to 20 centimetres, do not to any extent hinder the fatty globules in
their ascent to the surface. According to the author's observations,
warm milk when placed in ice in Swartz milk-pails requires from
three to four hours to cool down to about 10" C. It stands, therefore,
for several hours at temperatures at which the opposition oflfered to
the movement of the fatty globules is comparatively slight. This,
and the complete absence of vertical currents, are the causes why
more fa,ity globules rise into the cream-layer in the Swartz method,
during the first hours of cream-raising, than in any other older
methods of cream-raising. Even after 12 hours the yield of cream
in the Swartz method is almost always greater than in the Holstein
method under similar conditions. As soon as the temperature of
the milk falls below 10"' C, the opposition in the milk-serum rapidly
increases, and impedes the* motion of the fatty globules to the
surface more and more with the lapse of time. After 24 hours the

( M 175 ) H

114 SCIENCE AND PRACTICE OF DAIRYING,

yield of cream in the Swartz method is almost always less favour-
able than in the Holstein method, and still more so after 36 hours.
In general, it may be said that it is not possible with the Swartz
method to get in the course of the year so much fat as is possible
with other methods, as for example, with the Holstein or the Gus-
sander methods. The Swartz method is only suitable for dairying
in which the production of perfectly sweet cream and skim -milk is
the object aimed at, and in which the highest possible yield of butter
is not aimed at, but where it is desired rather to produce skim-
milk of not too poor a quality.

Such conditions occur in all dairies where the proprietors are
in a position to utilize the perfectly sweet and moderately skimmed
skim-milk for cheese-making, or for the rearing of calves, so that
a greater return may be obtained for the gallon of milk under
these circumstances than if the largest possible yield of butter
were obtained at the expense of the condition of the skim-milk.
The Swartz method is therefore of great value in manj^^ dairies, and
will continue to possess that value wherever skim-milk is made to
any extent into cheese. It has been introduced with peculiar
disadvantage into dairies in which the only object is a high yield
of butter, and in which no cheese is made.

In the Swartz or ice method, for the cooling of every kilo.
(2^ lbs.) of milk, on an average '85 kilo, (about 2 lbs.) of ice is used.
For North Germany, Sweden, and Denmark the price of a kilo, of
ice, taking into account the outlay, the depreciation, and the interest
on the ice-house, is about 32 pfennig. The cooling costs about
•27 pfennig. This is equal to 6 marks per cow (yielding 2000 kilos.
of milk in the year). The expense of an ice-house, built according
to the Danish method, and suitable for treating the milk of 200 cows,
amounts to about 6000 marks, and to about 4500 marks for an
ordinar^^ ice-cellar, capable of treating the milk of about 100 cows.

51. The Cold Water Method.- — A variation of the ice method is
the cold water method,^ which in its correct form only dilFers from the
former by the fact that an abundant supply of cold running water
is used instead of ice in cooling the milk, and that the milk is left
to cream for 36 hours or longer. In this method, the yield of fat from
milk is, on an average, greater than is the case in the ice method. It
is admirably suited for hilly districts in which the supply of cold

^ An application of this method, under the name of the Jersey Creamer, has attained con-
siderable popularity in England. — Editors English Edition.

THE COLLECTION AND STORAGE OF ICE. 115

flowing water is abundant, but the method is not suited for districts
in which this is not the case. An attempt was formerly made in
North Germany to introduce a method of cold water cooling, which
consisted of cooling with water that had been pumped through
ice, or with spring water that had been allowed to flow through a
suitable ice-house or ice-metre. This attempt, however, has met
with little success.

52. The Collection and Storage of Ice, — As the opinion is becom-
ing more prevalent every day that ice is indispensable for all the
best-equipped dairies, it may be not out of place to add to the
description of the ice method given in § 50 a few woi'ds on the
most suitable method for storing ice.

Very few dairies are in the position of being able to purchase at
economical prices the supply of ice they require from day to day.
Most of them are forced to lay in for themselves larger quantities
of ice, and to keep these for a long time in blocks or in ice-houses.
For this purpose, the great difficulty is to minimize, as far as possible,
the loss which is apt to take place through melting during warm
summer weather. The loss is partly due to the contact of the
vessels containing the ice with air, or some solid body which has a
temperature above the melting point of ice, but to a far greater
extent to the fact that during the warm weather a stream of warm
air is constantly passing night and day over the surface of the ice-
layers. All spaces in the ice-layer filled with air yield up their heat
to the ice, and melt a certain quantity of it. The confined air
finally assumes the temperature of melting ice, and becomes of
heavier specific gravity than the warm air outside, and tends to sink,
owing to its weight, through all the fine pores and crevices surround-
ing the lower portions of the ice-heap, outwards, and is replaced
by warm layers of air coming in from above and from the sides.

If ice be preserved in layers, as is commonly done, or in wooden
ice-cellars or in wooden ice-houses, it should be surrounded with sub-
stances which are bad conductors of heat, and which keep the air
from occupying the interstices and pores, besides offering a barrier
to the movement of the stream of air. In this way the loss through
melting may be largely diminished. If it were possible to j)revent
absolutely the movement of air over the blocks of ice, the loss would
be reduced to a very slight extent, provided the surface remained dry.

For this reason it is necessary to take precautions to provide a
good covering material for the roof. Sawdust, turf, and ashes are

116 SCIENCE AND PRACTICE OF DAIRYING.

well suited for this purpose. It is further important to keep the
covering material always dry, since it loses its properties as a bad
conductor of heat when it becomes wet. It may, indeed, generate a
certain quantity of heat through becoming fermented. It is further
necessary to provide every space which contains a heap of ice with
a chimney, so that evaporation of the water from any ice that has
melted may be allowed to take place, and the covering material thus
remain dry. Every ice-store should also be built in such a way that
the melted water may quickly run away.

Ice should preferably be kept in houses with solid walls which
effectually keep out the air, and which are sunk considerably under-
ground. They should only possess one entrance towards the top
of the building, and it should have double doors and a drain for
allowing the melted water to run off. A covering is not only
unnecessary, but in the case of its being of an organic nature, it is
positively a disadvantage. In such houses the passage of air
currents over the layers is very much impeded.

The less the intervening spaces between the layers of ice are, the
less will be the quantity of air coming into contact with the layers.
For this reason it is desirable that ice should be kept in regular
rectangular four-cornered pieces, which may rest close together, and
which should be cut, not by breaking, but by sawing. It is advis-
able to fill up the spaces between the separate pieces with sawdust.
Small pounded ice is not suitable for this purpose, nor is it effected
by pouring water in cold weather over the layers of ice. The
fewer the pores in the ice the better it keeps. On this account firm
good ice only should be used, not such as has been subjected for
some time to the action of a thaw. In order to obtain ice which is
hard and smooth on all sides, special blocks should have the snow
cleaned off them after every snowfall. Ice for use should never be
taken from the lower portion of the layer. If this be done, every
time the ice-stack is opened the cold heavy air which it contains is
expelled, and is replaced by warm air, which exerts a deleterious
action on the keeping of ice. If, on the other hand, the ice-stack is
opened from above, the cold heavy air remains in the stack, and the
warmer lighter air from outside cannot penetrate down into it. Ice
should be laid in during frost, and snow during a thaw. A snow-
stack collected during a thaw, and well compressed, lasts under
similar conditions even better than an ice-stack, because it contains
fewer air-spaces than the ice-stack.

METHODS OF CREAM-RAISING. 117

By a unit of heat is meant the amount of heat which is necessary to
raise 1 lb. of water one degree from the melting point of ice, that is, from
0^ to 1° C. The quantity of heat which Avill raise 1 lb. of water at any
temperature one degree, or, vice versci, the quantity which must be removed
from 1 kilogram of water in order to reduce its temperature one degree, is so
similar in amount to that amount of heat Avhich Ave have just described as
constituting a unit of heat, that it may be regarded as the same. According
to De la Provostaye and Desains, and Regnault and Petit, the latent heat
of water may be taken at 79-25, or, roughly speaking, 79 units of heat on
the Centigrade thermometer. In order, therefore, to convert 1 lb. of ice
at 0° C. into water at 0'' C, as much heat is required as Avill convert 1 lb.
of water at 0° C. to 79° C, or to raise 79 lbs. of water at any temperature
r C. 1 lb. of water at 79° C. Avill be reduced to 0" C. by 1 lb. of ice
after the ice has been melted, or Avill cool by one degree 79 lbs. of water
of any temperature. Vice versa, 1 lb. of ice at 0° C. in melting cools down
1 lb. of water at 79° C. to 0° C, or will reduce 79 lbs. of Avater at any
temperature by one degree. In these statements no account is taken of
the loss or gain of heat due to surroundings.

The specific heat of milk of average chemical composition — water being
taken as 1 — is, as Avas stated in § 4, about -85. In order to cool milk,
therefore, there is required only 85 per cent of the cpiantity of ice that
would be required to cool an equal quantity of Avater.

The question AA^hether it is economical and desirable to use ice-manu-
facturing machines in dairies has not been properly investigated. According
to M. Schrodt's experiments, it Avould seem profitable to use such machines
in very large dairies in tOAvns AA^here ice is unusually expensiA'e to procure,
but certainly not in small dairies, or in dairies Avhich can obtain their ice
cheaply.

53. Methods of Cream-raising. — Before the days of milk-centri-
fugal machines, and while the old methods of. cream-raising AYere being
perfected, the merits of different methods Avere often attempted to
be tried by comparative tests. In Denmark this Avas attempted to
be done by Avorking on milk of the same origin, churning the cream
separated, determining the yield of butter, and regarding as most
suitable the method Avhich yielded the largest quantity of butter.
This method, although someAvhat cumbersome and involving many
inaccuracies, had the advantage of not requiring chemical investiga-
tion. It is not suited, however, for reliable comparison. The
author preferred for this reason, in his comparative experiments,
which Avere likewise carried out on milk of similar quality, to
determine the percentage of fat in the milk and the skim-milk, as

118 SCIENCE AND PRACTICE OF DAIRYING.

well as the weight of the cream obtained, and to calculate what
percentage of the entire fat in the milk was obtained in the cream.
This percentage number he called the cream-yielding coefficient.
This method has been followed by others.

As the cream-yielding coefficient depends not only on the per-
centage of fat in the skim-milk, but also on that of the whole milk,
and on the relative weight of the cream and the skim-milk, it affords
an exact indication of the yield of cream in different cases, provided
the milk used in the experiments has a similar percentage of fat,
and that the relative weights of the cream and the skim -milk
remain constant.

The calculation of the cream-raising coefficient is very simple, as the
following example will indicate: —

100 lbs. of milk containing 3-4 per cent of fat yielded 20 lbs. of cream
and 80 lbs. of skim-milk, containing "5 per cent of fat.

The total quantity of milk contained, therefore, 3 '4 lbs. of fat.

In the skim-milk there remained = '4 lb. of fat.

100

In the cream, therefore, there was 3 lbs. of fat.

These 3 lbs. make =88'24 per cent of the total quantity of

the 3-4 lbs. of fat. ^'*

The cream-raising coefficient is therefore 88*24 per cent; that is, 88*24
per cent of all the fat contained by the milk was yielded in the cream.

In the case of a sample of milk containing the avei'age quantity of 3*4
per cent of fat, and yielding on an average 15 per cent of cream, in the
Holstein method, and allowing 36 hours for cream-raising, the cream-
raising coefficient throughout the year would average 84 per cent. The
skim-milk, therefore, would contain in this case "64 per cent of fat, and if
97 per cent of the fat in the cream were converted into butter containing
81 per cent of fat, then from 100 lbs. of milk 3*3 lbs. of butter would
be obtained, or for every lb. of butter obtained, 30*3 lbs. of milk by
weight are used. Under similar circumstances, it Avill be found in practice
in the ice method of creaming, when the cream-raising period lasts for 12
hours, that the cream-raising coefficient on the average of a year will
amount to 74 per cent. In such a case the skim -milk would contain
1*04 per cent of fat, and for every 100 lbs. of milk 2*91 lbs. of butter
would be obtained. That is, 34*37 lbs. of milk are used for every pound
of butter produced.

In all the older methods, creaming was effected through the
influence of gravity, which is practically always the same. It is

CENTRIFUGAL FORCE. 119

quite different, however, in creaming milk in centrifugal separators,
for in this case the force can be regulated at will within compara-
tively^ wide limits. In such a method, the aim is to separate the
largest possible ainount of the fat, by centrifugal action, which is
much more powerful than the force of gravity, and which in the
older methods, depending on the force of gravity, was not obtainable.
An accurate indication of how far this is effected is furnished by the
percentage of fat present in the skim-milk. The creaming coeflficient
is not an indication of this.

54. Centrifugal Force. — One of the common properties- of matter
is its inertia. This is manifested in a body by the opposition it
offers to any change in its motion. Any such change must be
effected by force. Inertia acts in such a way, that a body set in
motion tends to maintain the direction of its motion unchanged, i.e.
in a straiglit line. If a bod}^ is forced to move in a circle, in every
point of its movement it manifests a tendency to move at a tangent
to each point of the circle. The direction, therefore, to which it
tends to go has to be changed from point to point. The force
which effects this is known in physics as centripetal force. It is
produced when a body is swung round in a. circle at the end of a
string by the tenacity of the thread, and in the case of a liquid
being put in circular motion in a vessel by the sides of the contain-
ing vessel. Since every force requires a counter force, a force
which acts in exactly similar but opposite direction, every body
moving in a circle is subjected to a force which moves from the
centre in the direction of the circumference along- the radius, a force
exactly similar in its manifestation to the centripetal force. This
force is called the centrifugal force. The centrifugal force is the
force which overcomes the inertia of the material, and represents
the resistance offered by a body in motion, to change in its direction
of movement, and acts upon every body, moving in a curve, that is,
in a line, the direction of which changes from point to point. In
§ G the acceleration <p, which the fatty globules experience when they
are subjected to the action of centrifugal force, was shown to be
capable of being calculated as follows: —

M = a.(gVl)x(2A!^yx«^xr.

In which a^ indicates the factor, representing the inertia, 8 and S^
the viscosity of the milk-serum, and the butter- fat; n the Ludolph

120 SCIENCE AND PRACTICE OF DAIRYING.

number, it the number of revolutions of a fatty globule in a minute,
and 7- the radius vector of a globule. From this formula, it is seen
that the centrifugal force acting on the fatty globule is in simple
proportion to the distance of the globule from the centre point
around which the revolutions are made, and increases in quadratic
proportion to the revolutionary speed.

55. The Value of Centrifugal Force for the Creaming of Milk. —
The natural force of gravity, which is universally and at all times
freely available, and which was formerly exclusively used in cream-
raising, acts with uniformity. Not merely does it require a certain
time in which to obtain the best possible results, but even under the
most favourable conditions it fails to obtain complete separation of
the cream from the milk. Much more perfect separation, and a
shortening of the time necessary for cream-raising, can only be effected
by the application of a force, which will impart to the fatty globules
an impetus far exceeding that given by gravity. This force is
centrifugal force. It is not to be had gratis, since its application
costs money; but it is at all times easily utilized for the purpose of
cream-raising, and can be applied in such a manner that its force
exceeds that of gravity to the extent of more than a thousand-fold.
It is only necessary to subject the milk, in suitable vessels, to a very
rapid rotatory motion. The idea of utilizing this force in dairying,
and thereby of curtailing the period for the separation of the
cream, does not date further back, it would seem, than the middle
of the century, when C. J. Fuchs carried out experiments in
Carlsruhe on cream separation by centrifugal force. About 1860
similar experiments were carried out by Albert Fesca, in Berlin,
and, in 1864, by Antonin Prandtl, in Munich. It was first demon-
strated to be practical in 1877 by the German civil engineer William
Lefeldt, in Schoninofen, in Brunswick, who, after more than fifteen
years of arduous experimentation, succeeded in producing a milk-
separator, which, if imperfect, was nevertheless practical. Since 1877
the structure of milk-separators has been improved from year to year,
and at present there are quite a number of serviceable separators of
different structure known by different names. At present all
separators are so arranged that when at work they are fed with a
continuous stream of milk, and give out in return separated cream
and skim-milk. The utilization of these highly serviceable machines
has extended more and more, especially since efficient separators,
capable of being driven by the hand, have been devised, and they

MILK IN THE SEPARATOR-DRUM.

121

Fig. 28.— Sectional Illustration of the Alexandra Creani-separator.

2, Float for regulating inflow of milk from large receiving tin; 3, strainer for new milk ; 107, cast-
iron cover ; 108, inlet funnel holding strainer for new milk ; 109, inlet tube in which No. 108
fits to lead new milk into steel cylinder No. 9; 6, large tin cover over which the separated
milk flows ; 7, small tin cover over which the cream flows ; 9, steel cylinder in which milk is
separated ; 10, screw for regulating thickness of cream ; 11, outlet tube for cream ; 12, outlet
tube for milk ; 13, cast-steel spindle with ball-shaped head, on which the steel cylinder rests
and balances itself perfectly in running; 14, steel pin for bottom of No. 13, which when worn
can be taken out by being heated slightly, and another put in ; 15, steel balls for footstep
bearing, on which No. 14 runs ; S3, steel set-pin with lock nut for all bottom bearings : by
slackening the lock nut and screwing this set-screw to the right or left the spindle No. 13 can
be raised or lowered as desired ; 84, bevel pinion with 23 teeth, and spur-wheel with 120 teeth;
85, steel pinion with 10 teeth on spindle with leather wheel; 86, leather spur-wheel with
98 teeth and brass flanges eacli side ; 87, steel pinion with 17 teeth on No. 13 ; 88, steel spindle
for carrying leather wheel ; 89, steel spindle for bevel pinion and spur-wheel ; 79, brass bush-
ing for No. 88; SO, bottom bearing for No. 79; 81, bottom bearing for No. 13; 82, bottom
bearing for spindle witli bevel pinion ; 65, bevel wheel with 108 teeth; 49, handle ; 48, handle
spindle; 28, main bushing for spindle; 110, india-rubber ring for No. 28, to give elasticity to
sjjindle and prevent vibration with bowl; 111, tliin india-rubber ring for cast-iron top, to
make same water-tight; 76, cast-iron casing with fastenings and thumb nuts holding cylinder;
77, cast-iron casing holding gearing 78, cast-iron base which can be taken out by unscrewing
set-screws and putting the two screw handles sent with each machine in their places.

122 SCIENCE AND PRACTICE OF DAIRYING.

are every day displacing to a larger extent the older methods of
cream-raising. Up till 1886, the only kind of separators used were
tlie larger separators driven for the most part by steam-engines, or
horse-power, and in a few cases by other motors, and the application
of which only paid in large dairies. For the sake of simplicity the
larger machines driven by steam, &c., may be designated powder-
separators, as distinguished from separators driven by manual power,
which may be called hand-separators.

[The illustration in the preceding page of a section of the Alex-
andra cream-separator, with the explanation of parts, has been
inserted by the Translators to assist students in understanding and
describing the construction of the separator.]

56. Milk in the Separator- drum. — That portion of the separator
which is destined to hold the milk, and which is known as the drum,
forms the essential part of every separator, and revolves round a
horizontal or vertical axis. Whatever its shape, whether cylindrical
or bulbiform, round or pear-shaped, &:c., it must always be a rotat-
ing body.

When in motion, and filled with milk, the force of gravity acting
upon the separator-drum may be neglected, when compared with
the centrifugal force, which is several thousand times stronger;
indeed the force of gravity may be said to be replaced by centrifugal
force, and one may assume that the same action and conditions take
place in the milk, when shut up in the revolving separator-drum, as
take place when milk stands quietly at rest.

Just as milk, which is poured in a slow, steady stream into a
milk-pan standing at rest, finds at once the lowest part of the can,
namely the bottom, and spreads itself over the bottom in a horizon-
tal layer, and gradually fills the vessel from the bottom to the top,
so does milk allowed to flow into a separator-drum, when revolving,
find its way with lightning-like rapidity to the most distant part of
the drum, and there spread itself out in a ring bounded by a free
and almost cylindrical surface, and the drum is thus gradually filled
from the outside to the inside, that is, in a direction exactly opposite
to that of the direction of the centrifugal force. All separator-
drums, without exception, when in motion, and when the milk is
allowed to flow in, are thus filled from the remotest part of the wall
to the axis round which the drum revolves. It is quite immaterial
what part of the drum the milk flows into. Any other method of
filling is inconceivable.

THE INFLOW OF MILK INTO THE SEPARATOR-DRUM. 123

Just as milk, standing in a milk-pan at rest, exercises a pressure
on the bottom and sides of the pan, due to the force of gravity, so
precisely milk, in a separator-drum in motion, exercises a pressure
on the sides of the drum, which is caused by centrifugal force, and
which is proportional to the strength of that force.

In the same way, just as in milk, standing in a milk-pan at rest,
the fatty globules move upwards, in a direction opposite to that in
which gravity acts, so the fatty globules in a separator-drum, filled
with milk and in motion, travel in a direction opposite to that of
centrifugal force, that is, from outside to inside. In this case, as in
the former case, the layer of cream rises to the surface, which in the
separator-drum is that portion nearest to the axis of revolutioiL

57. The Inflow of Milk into the Separator-drum. — The drums of
many of the older separators suffered from this disadvantage, viz.
that the milk, flowing into them when revolving, was led in on the
top of the cream layer, through which it naturally at once sank
on account of its high specific gravity. This influenced the amount
of fat obtained. Nearly all the drums of the newer separators are
so arranged that the milk flowing into them is led in by a suitable
arrangement to the inside of the circle of milk, and in this way the
verj^ considerable force with which it has to press through the layer
of cream is avoided, and the full yield of fat is thereby obtained.

58. The Outflow of Cream and Skim -milk from the Separator-
drum. — The outflow of the liquid from a filled separator-drum in
motion takes place with considerable energy, and is due to the
driving power employed, being in no way connected with the centri-
fugal force. This force is greater the further the spot is from the
revolving axis. Its amount is proportional to the square of the
rapidity of the revolving motion at this place, and increases, in a
simple regular proportion, with the radius vector of the spot of
outflow. In order, therefore, to reduce as far as possible the force
with which the liquid flows out, and thus to effect a saving in
motive power, the exit for the outflow of cream and skim-milk is
chosen as near the revolving axis as can be. The exit for the cream
can be placed directlj^ on the surface of the ring of milk, that is to
say, as near as it can possibly be to the axis; whereas the exit for the
outflow of skim-milk, on account of the higher specific gravity of this
liquid, must be placed slightly further back. Tlie skim-milk is con-
ducted either by means of tubes, which run back to the wall of the
drum to the surface of the milk-ring, or by means of a special space

124 SCIENCE AND PRACTICE OF DAIRYING.

made in the drum, and which is only accessible from the wall of the
drum, and into which only skim-milk can come. The surface of the
skim-milk is thus brought as near as possible to the revolving axis.
In the case of such separators as those of Burmeister and Wain, the
cream and skim-milk are conducted from the surface, by means of
skimming-tubes, to the outside.

59. The Regulation of the Proportional Weights of Cream and
Skim-milk in the Separation of Milk by Separators. — In the drum of
every separator in use, the amount of cream and skim-milk which
flows out must be together equal to the amount of milk which flows
in. The proportion of the weight of cream to skim-milk is deter-
mined by the rapidity with which the milk enters the separator,
and in all separators, therefore, without exception, can be regulated
at will by this means when the separator is in motion. By this
method of regulation the amount of the cream obtained will be
altered, a thing which does not happen with an arranged equable
motion. For this reason, in almost all separators there are arrange-
ments whereby it is possible at will to regulate the quantity of
cream with a uniform inflow of milk. In the case of the separators
of Burmeister and Wain this is effected by sinking the skimming-
tube for skim-milk, either deeper or shallower, in the surface of the
liquid, a thing wdiich can be very easily effected when the drum is
in motion. In the case of most other separators, the necessary
precautiona,ry measures should be taken before creaming begins,
and while the drum is at rest,

AVhere the place of outflow for the skim-milk is equidistant, and where
the conditions under Avhich the milk flows out are otherwise the same, and
the outflow of the cream is not in any Avay hampered, the more milk
that enters the drum in a definite time, the more cream will be given
out, the slower Avill the drum revolve, and the cooler Avill be the milk
Avhich is to be creamed. The first case needs no further explanation.
With regard to the second, less skim-milk flows out in a definite time
under reduced pressure, and in consequence of this the .surface of the milk-
ring is slightly moved towards the revolving axis, while in the third case
the friction towards the outflow exit is strongly increased, in virtue of
Avhich the amount of skim-milk flowing out in a definite time is somewhat
diminished.

60. The Size and Reliability of Separator-drums. — The follow^ing
regulations are deduced from the equations given for calculating
the acceleration of sepai'ators in § 54: —

THE SIZE AND RELIABILITY OF SEPARATOR-DKUMS. 125

(1) In the case of two exactly similar separator-drums making
an equal number of revolutions per minute, but one twice as broad
as the other, the acceleration in the former at the spot furthest
from the centre is double that of the latter.

(2) In the case of two perfectly similar separator-drums of
exactly the same size, but one of which revolves at double the rate
of the other, that is, has twice the speed of the other, the centrifugal
acceleration on the spot furthest removed from the centre is four
times as great in the former as in the latter.

From this it will be seen that the action of centrifugal force on
the milk may be increased in a double manner, namely, either by
increasing the size of the separator or by increasing its speed.
Since, however, in the case of doubling the diameter of the drum
the action is only increased twofold, but, in doubling the speed,
fourfold, the second method will be seen to be the more efficacious.
The second method is also to be recommended on other grounds.
Large drums are less hand}'', and are more difficult to work than
small ones. Since large masses of metal of a perfectly uniform firm
quality are more difficult to be obtained than small masses, there is
required for large drums a greater degree of security; in other
words, the revolving speed of large drums must be measured with
very special care, and this can only be done at the expense of
efficiency. Finally, it must be borne in mind that large drums
which efiect the creaming of large quantities of milk in a compara-
tively short time require a comparatively large driving power, and
that it is more convenient, and generallj" also cheaper, to utilize a
comparatively low driving power for a longer time than a large
driving power for a short time. For this reason the use of large
drums, such as were formerly largely made, has decreased in the
course of time more and more, since they have not been found to be
suitable in practice. Separators under 50 kilograms (212 lbs.) in
weight are now generally used with drums, and they can only hold
when in work a few kilograms (10 to 20 lbs.) of milk, generally
between 4 and 8. The smaller of these drums is worked at a
speed of 6000 to 9000 revolutions per minute. In the case of
most of the separators at present in use, milk which has to be
separated only remains a short time in the drum, often not one
minute, and rarely more than three.

When the separator is in use, the sides of the drum have to stand
very considerable internal strain, owing to the pressure of the milk

126 SCIENCE AND PRACTICE OF DAIRYING.

and their own weight, and must on that account be very strong.
The first and most important quality of every separator-drum is its
strength.

61, Milk-separators at Present in Use. — Since 1877, the construc-
tion of separators has been improved from year to year. While
the usefulness of separators has far exceeded the most confident
expectations at first entertained, it cannot be asserted that we have
yet reached their limits of capability; indeed, it would appear as if we
had now reached a point from which a fresh start towards further
improvement could be made. Not taking into account some of the
separators of antiquated construction, and the separators which,
although no longer made, are still in use in various places, we find
that there are only five different kinds of separators for power-use,
and six for hand-use, employed in German dairies, regarding which
the following details may be given.

62. The Lefeldt Separator. — In the manufactory of Lefeldt and
Lent.^ch at Schoningen, in the Grand Duchy of Brunswick, seven
separators of different sizes and construction are made at present,
of which three are worked by steam, one by a winch, and three by
hand. Separators for hand-use were tirst constructed in 1877. The
separators worked by power have undergone many changes in their
construction from the introduction of the first in 1877 to the one at
present in use. From the end of 1879 they have been constructed
for continuous use. They are sold under a guarantee, and can be
unreservedly recommended. The separators worked by power
(fig. 29) require good, pure lubricating oil.

Of exactly similar construction as at present made, only of
different sizes, are the three separators, Nos. 0, 1, and 2, for steam-
use. At present a new separator is being made in this manufactory,
which is to be called the "multiplex". The three separators, Nos.
0, 1, and 2, have cylindrical upright drums closed above and open
below, constructed with Siemens-Martin steel, with four continuous
flanges, and Avith a thickness in the case of (0) and (1) of 1"1 centi-
metres, and in the case of (2) of 1*4 centimetres. The largest
internal diameter measures in the case of (0) and (1) 30, and in the
case of (2) 40 centimetres. The first-mentioned two have an under
opening of 20 centimetres, and the last of 30 centimetres broad.
The milk coming in, runs first into a bowl-shaped aperture in the
upper portion of the drum, and is conducted hence by means of

THE LEFELDT SEPARATOR.

127

canals, which lie behind the layer of cream formed during the
motion, into the internal portion.

The cream flows over the surface of the lower circular opening
into the lower space of the covering of the drum, and the skim-milk
is conducted by means of four tubes, leading almost to the edge

fig. 29.— Lefeldt's Separator. (Section.)

of the drum and the drum-lid, and passes through the drum-lid into
the neighbourhood of the surface of the ring of milk, where it is
conducted into the upjoer covering.

By setting the drum in motion one can make the exit for the
skim-milk at the upper end of the tube narrower or wider, so that
during the operation more or less cream may be obtained, A hand-

128

SCIENCE AND PRACTICE OF DAIRYING.

indicator is connected with the well of the drum. After creaming
has been effected, the drum, gradually settling to rest, empties
itself.

The three separators for hand-use, Nos. "0, 0, and 1, and the
separator for the winch, possess an improved arrangement which

Fig. 30— Arnoldt's Hand Separator. (Perpendicular Section through the Drum.)

has been devised lately by the senior engineer of the factory, Herr
Oswald Arnoldt (hg. 30).

The milk enters through one of the taps, and the cream and
skim-milk are conducted away through separated divisions of a tap,
which is surrounded by double rings of white metal. Their thick-
ness in the case of No. (0) is exactly "1, and in the case of the others
'3 centimetre, and the greatest internal diameter in the case of
(■0), (0), and (1), and (2) (for winch power) is respectively 5, 9,
9, and 11 "5. Further details are contained in the following
table : —

SEPARATORS MADE BY THE SEPARATOR CO., STOCKHOLM.

129

Xumber
of Lefeldt
Separator.

O
I

II
00

o
I
II

Xumber

Milk

Milk
Weight of Contents „* t> „..„,,, cipnarateil
Drum with of Drum i tions ner i ner

CninHIp in i '•'on!! pel pel

^ Motton. i ^^"'"t«- H^^r-

K^'.

Kg.

27-5

6-0

7,000

32-5

9-0

6,500

660

16-0

6,000

3-00

0-3

10,000

5-50

1-3

8,750

7-25

2-3

8,750

9-25

4-0

8,750

Kg.

600

900

1200

100

250

400

The Cost

of
Separator.

500
750
1000
175
250
500
600

of
Gearing

M.
100
100
150

100

Observations.

Steam-power.

Hand
power

Winch.

4. '.-50

-handle-turns

per minute.

63. Separators made by the Separator Co., Stockholm.— This com-
pany is represented in Germany by the BergedofF Iron Co., in
Bergedoff, near Hamburg, and
makes in all, at present, four-
teen different separators for
machine and hand use. They
may be divided into separators
of the De Laval and the Alpha
types.

(a) De Laval Separators. —
Of these there are at present
two kinds. The De Laval
separators have in course of
time been very much improved.
The first was introduced into
Germany in 1879, and was u.sed
at the co-operative dairy at
Hamm, in Hamburg. It was
the first employed to do con-
stant work in Germany. Its
drum had three independent
parts, which were screwed to-
gether, and were made tight with
rubber rings. In the year 1S81
the arranfrement of the drum
received its first improvement,

which con.sisted in replacing the three independent parts by one
piece, consisting of a cup-like box provided with flanges. In 1883
the drum received the simple form which it still retains. In the
year 1886 Dr. De Laval invented his steam-turbine, which he

(M175) I

Fig. 31.— Steam-turbine Separator.

130

SCIENCE AND PRACTICE OF DAIRYING.

applied directly to the separator, and by means of it he imparted
to the creaming of milk by centrifugal machines a simplicity that
had been previous!}^ undreamt of. The first steam-turbine sepa-
rator, worked in Germany, was used in the co-operative dairy at

Elmshorn, in Holstein,
where it was placed
in the beginning of the
year 1887. By means
of the turbine the use
of steam-engines and
the customary con-
nections for securing
sjDeed could be dis-
pensed with. Thus
was effected a large
saving of plant, of
capital, of space, and
of lubricating oil,
while the efficiency of
the work was increased.
In order to set it in
motion, all that is
necessary is to press
the cock gradually up-
wards, which connects
the steam with the
turbine. The De Laval
separators (figs. 81
and 32) require, there-
fore, according to the
claim of the manu-
facturer, steam of only
45-lbs. pressure, and
the Alpha, steam of only 30-lbs. pressure. Nevertheless it is advis-
able to use steam of 60 and 45 lbs. pressure respectively.

The De Laval separators are especially characterized by the
simplicity of their structure and their serviceableness, and by the
fact that they are not easily susceptible to disturbing influences.
They are excellently suited for private dairies in which creaming is
necessarily left to unskilled workers. They have stood the test of

Fig. 32.— Perpendicular Section of Steam-turbine Separator.

SEPARATORS MADE BY THE SEPARATOR CO., STOCKHOLM. 131

time, and can be unreservedly recommended. So also can the Alpha

Fig. 33.— Two Laval Separators \nth Milk Warmer.

separators, which have been well tried, and which have given great
satisfaction wherever they have been used.

Fig. 34.— Perpendicular Section through the Drum of tlie Laval Hand Separator.

The upright drums, open at the top, and -9 cm. broad in their broadest
place, are made out of malleable cast steel, have a liulbous form, a cylindri-
cal-shaped neck, 11-2 centimetres in width, and a large internal diameter of

132

SCIENCE AND PRACTICE OF DAIRYING.

28-8 centimetres, and a continuous flange inside. In the case of No. 2
the drum is somewhat higher. The milk which comes in falls through
the top opening of the drum into a cup 5-2 centimetres wide, resting
upon the foot of the drum, and flows from this to a tube under the layer of

cream, formed dur-
ing the operation.
The cream runs
outwards through
a narrow, shallow
slit in the side of
the neck of the
drum, and the skim-
milk through a tube
leading up from
the widest part of
the drum, then
through a small
opening about half-
way up the neck of
the cylinder, which
can be set, when
the drum is at rest,
either narrower or
wider, and of course
each liquid by itself
runs into a special
circular-shaped re-
ceiver at the top of
the cover. A simple
indicator, Avhich is
placed in the well,
renders it possible
to determine the
rapidity of the re-
volutions of the
drum per minute.

Fig. 35.— Alpha Separator No. 1. (Perpendicular Section.)

(h) De Laval Hand-separators.— Dv. De Laval devised the first
useful hand-separator in 1886. At present two such machines are
made, the separator (K), which has a horizontal cylindrical drum,
and the Baby separator, which has a vertical cylindrical drum.
The drums of both these separators have short cylindrical necks,

THE SEPARATORS OF BURMEISTER AND WAIN.

133

two continuous lianges in the inside, and a thickness of 25 centi-
metre.

The hand-separator (K) has a horizontal drum, Avhich, in the Avidest
place in the inside, is lO'T and in the neck 6'7 centimetres wide. The
milk enters at one side of the drum, and on the other it passes through
an opening in the neck of the drum, the skim-milk being separated by
means of two white-metal tubes, which surround the neck of the drum.
One of these tubes, when the drum is at rest, can be adjusted either
narrower or wider.

The Baby separator is, in essential points, of similar construction to the
separators for machine use. The drum is internally 9 '8 centimetres, and
round the neck 6 "6 centimetres Avide, and is set in motion by means of a
toothed Avheel.

Both separators attain their maximum speed when the handle makes
40 revolutions per minute.

We have to thank the BergedofF Iron Works for the followino;
details : —

Number of
Separator.
De Laval.

Weight of
the Drum

with
Spindle.

Milk

Contents

of Drum

in Motion.

Number of
Revolu-
tions per
Minute.

Milk

Separated

in the

Hour.

The Cost

Observations.

of Sepa-
rator.

of
Gearing.

A I
All
E I
E II
K

Baby

Kg.

20-5
25-0
20-5
25-0
4-5

3-5

Kg.
6-0
8-2
6-0
8-2
1-6

0-8

7000
7000
7000
7000
7000

6400

Kg.
400
600
400
600
150

Marks.

550

800

1100

1500

550

260

Marks.
100
100

Machine-driven.
Steam-turbine.

Hand-use (liori-
zontal drum).

Hand-use (verti-
cal drum).

(c) Al^yha Se'parators for Machine Use. — These have been known
in Germany since 1890, and at present three different sorts are
manufactured, viz. Nos. (1), (2), and the Alpha pony (fig. 35).

{d) Aljyha Separator for Hand Use. — Tliese at present in use are
of three numbers: Alpha K Avith horizontal, and Alpha B, as well as
Alpha S or Baby, Avith perpendicular steel drum (figs. 3G, 37, and
38). The drums of these three machines attain their most favour-
able speed when the handles make forty revolutions per minute.

64. The Separators of Burmeister & Wain. — As early as the
year 1872, the Avell-knoAvn chemist, Storch, of Copenhagen, drcAV the
attention of Danish agriculturists to experiments carried out by

134

SCIENCE AND PRACTICE OF DAIRYING.

•mf

im^

THE SEPARATORS OF BURMEISTER AND WAIN.

135

136

SCIENCE AND PRACTICE OF DAIRYING,

Antonine Prandtl in Munich, regarding the separation of cream from
milk by centrifugal force. In consequence of this, in 1873, experi-
ments were conducted with the Eimer centrifugal separator, and an
engineer, Mr. P. J. Winstrup, undertook the construction of a
milk-separator. He made experiments in 1878 with a separator

constructed by himself
in the dairy of States-
Councillor Valentine
in Jeddesdal, and in
1878 brought out a
workable separator,
which, however, was
not largely adopted in
practice. In the mean-
time, several other en-
gineers, particularly
L. C. Nielsen, had been
occupying themselves
^^•ith the construction
of milk-separators. In
the year 1878, there
had been set up on a
farm near Copenhagen
a separator for regular
work,Kongen's Nytorf
separator No. 10, de-
vised by L. C. Nielsen,
and made in the manu-
factory of Peterson
Brothers in Magle-
kilde, near Roskilde.
In the course of a year
it was distinctly im-
proved, and in the year 1879 it was changed into the form which
it at present possesses, and quickly became known under the name
of Nielsen & Peterson's patent separator. In the year 1881, tlie
Engineering and Ship-building Co. of Burmeister & Wain bought
the patent of 1878, and since that time the separator has been
known as Burmeister & Wain's separator (fig, 39). It has been
extensively used, especially in Denmark itself. It is warranted, and

Fig. 40.— Hand-separator (Burmeister & Wain).

THE SEPARATORS OF BURMEISTER AND WAIN.

137

can be unreservedly recommended. At present four other separators
are used or made, the bowl-separators (A) and (B) for machine use,
the separators (X 1), (A), and (X 2) for hand use (figs. 40 and 41).
The separators of Burmeister & Wain are characterized by their
elegant construction and their smoothness of working. They allow
the quantity of cream to be regulated during the revolution of the
drum, cind alone among separa-
tors offer the extremely and uni-
versally valuable advantage,
that it is possible, if desired, to
pump up the cream and the
skim-milk several metres in the
ascending tubes. Cream and
skim -milk gusli out at the end
of the exit tubes more strongly
than is the case with other
separators. Owing partly to
their fine construction, they
require to be carefully and
intelligently handled.

They are provided with a self-
acting security arrangement,
which prevents an increase of
the speed above the regulated
degree. It may be added that
these separators may be used
in the simplest manner for pre-
paring emulsions of oil and
skiin-milk for calf feeding.

The following are the dimen-
sions of a number of separators
made by Burmeister & Wain : —

Tig. 41— Burmeister & Wain's Hand-power
Separator. (Perpendicular Section.)

'N'umber of

Separator.

Burmeister

& Wain.

Weiglit of
tlie Drum
without
Spindle.

Milk
Contents
of Drum

in
Motion.

Number of
Revolu-
tions per
Minute.

Milk
Separated
per Hour.

Cost of Separator.

Observations.

A A
B
X 1

Kg.
120
120
54
3-25
3-75

Kg.

58-0

580

16-5

1-25

1-66

Kg.
2700
2700
4000
7200
7200

Kk.
1400
1400
700
150
200

Marks.
835
835
467

285
400

Marks.
425
425

288

138

SCIENCE AND PRACTICE OF DAIRYING,

65. The Victoria Separators. — These are made in the works of
Messrs. Watson, Laidlaw, & Co., Glasgow, and have been known since
the end of the year 1879. Six different sizes of these separators,

Fig. 42.— Victoria Hand-power Cream Separator.

known as (1), (2), (3), (4), (5), (6), have been used in Germany (figs. 42
and 43). The first three are for hand use, the last three for machine
use. Up till now these separators lack an arrangement for regulat-

THE VICTORIA SEPARATORS.

139

Fig. 43.— Sectional View of Victoria Hand-power Cream Separator.

140

SCIENCE AND PRACTICE OF DAIRYING.

ing the amount of cream to be obtained from an equal flow of
mHk.^

66. The Balance Separators. — The discoverer and first patentee
of this separator, which was made known at the beginning of 1888,
was a Dane, whose nom de ]_)liimc was Musician. In February, 1888,

a similar separator
under the name of the
Nil son separator was
made by the firm of
Mot & Co. of Paris,
and in the same month
a balance separator
supplied by the Carl
Peter Co. was used on
the estate of Emken
Dorf in Holstein. The
construction of the
balance separators has
undergone, up to the
present time, a number
of changes, but they
have been compara-
tively little tried in
practice. The Carl
Peter Co., which has
acquired the patent,
makes these separators
of six different sizes,
three for machine use,

with drums made of hardened steel, and three for hand use, with

drums made of hard hammered copper (fig. 44).

67. The Separators in Use at Present in Germany. — The separ-
ators at present in use in Germany are of seven types — those of
Lefeldt, De Laval, Burmeister and Wain, Alpha separators, Victoria
separators. Balance separators, and Dr. O. Brown's separators. The
first six types include several large separators of different sizes for

1 Messrs. Watson, Laidlaw h Co. point out, on the other hand, that in their machine the
proportionate yield of cream is altered by increasing or diminishing the supply of milk, which
can be done without stopping the machine. They claim that this method of obtaining thick
or thin cream is advantageous, as it obviates the necessity for having any special arrangement
in the drum for this purpose. — English Editors.

Fig. 44.— Section of the Balance Separator.

THE BEST SEPARATORS, 141

power use, as well also as for hand use. The separators of Dr. O.
Brown are hand-separators. Altogether there are used in German
dairying 41 separators, 22 for power use and 19 for hand use.
The separators of De Laval and Bunneister and Wain are war-
ranted. Their merit is established. The Alpha separators have also
been proved to be satisfactory, from the results of many exhaustive
experiments which have been carried out on them. As to the capa-
city of the remaining separators, further reliable experiments and
tests are required to enable a correct judgment to be formed, and to
prove their practical value.

68. The Best Separators. — The value of a separator is determined
chiefly, though not exclusively, by its capacity for work. This is
best measured by the quantity of milk which it can cream in an
economical manner, at a uniform rate of speed, and at a flxed cost
per hour, when fed with a regular supply of warm milk at 80° C,
the skim-milk to contain an average percentage of fat of 25 per
cent. A separator possesses, therefore, the largest capacity for work
which creams in an hour, under the above conditions, the largest
quantity of milk. Which is the best separator at the present time it
is impossible exactly to say. In the middle of the eighties, one might
assert that the three at that time most in use differed very little from
one another. Among the six different separators for power use which
are at present used, much difference, however, exists, since a new
advance would appear to have been made in the perfecting of
separators, which in time may permit us to await again a certain
settlement in the capacity of the different separators. The most
efiicient separators are not always the best. The best separators
may be described as those that are best suited, from a technical and
economical point of view, for the special conditions under which
they are to be used. Whether a separator will ever be found which
will prove to be the best under all conditions, it is impossible to say.
It is also very questionable whether circumstances may not exist in
which, where very slight diflferences in their capacities exist, the
less capable of two separators may not be preferable, since it may
possess certain advantages and conveniences which, although the}^
appear to be of little importance, have yet a material value in the
circumstances in which they are used.

69. The Cream-raising CoefBcient in connection with the Use of
Separators. — As has already been mentioned in § 53, the extent
to which cream has been separated from milk by centrifugal

142 SCIENCE AND PRACTICE OF DAIRYING.

force is best ascertained by the percentage of fat in the skim-milk
obtained. Considering the efficiency with which separators at
present do their work, one is justified in demanding that in dairies
where separators are in use the coefficient of cream-raising should
be such that a percentage of "2 to '3 — on an average "25 — of fat is
obtained in the skim-milk.

It is only under very exceptional circumstances that the skim-milk
obtained by separators contains as little as '1 per cent of fat. Just as in
the case of Avhole-milk which has been evaporated down to dryness, the
fat is less easily extracted by ether, so it is found that, in the gravimetric
determination of fat in skim-milk, if not done with care, the percentage
of fat may quite easily be placed too low. Examples of skim-milk obtained
by separators under ordinary conditions containing less than "15 per cent,
or much less than '1 per cent of fat, are, therefore, to be viewed with
suspicion.

70. The Conditions which Influence the Cream-raising Coefficient
in connection with Separators. — The coefficient of cream-raising ob-
tained with milk-separators depends on the following conditions: —

(1) On the strength of the centrifugal force used to separate the
milk, or on the rapidity of the revolutions of the drum. As has
already been pointed out, the centrifugal force increases with the
square of the number of revolutions made by the drum in a minute.
If the drum of a separator does not revolve quickly enough, or up
to the required speed, much fat will remain behind in the skim-milk,
which might, with greater care, be easily obtained in the cream.

(2) On the time during which the milk is submitted to centri-
fugal force, or on the quantity of milk which is creamed per hour.
The more milk that is creamed in a given time, the less favourable
will the coefficient of cream-raising be.

(3) On the temperature at which cream-raising takes place.
The warmer the milk the better does it cream. From 5° to 25° C.
upwards, the percentage of fat in the skim-milk rapidly decreases,
and from that temperature always more and more slowly up to the
boiling point of milk.

These three conditions are of enormous importance, and since
they are always under control, it may be said that the success of
cream-raising depends on the art and method in which separators
are worked. It is further influenced by —

(4) The construction and nature of the separator. For example,

CREAM-RAISING COEFFICIENT. 143

whether the milk-ring in the drum is more or less strong, whether
the drum works regularly and quietly, and whether the machine
can be conveniently and simply worked.

(5) On the special properties of the milk which is to be
separated. Under ordinary conditions, milk brought from a dis-
tance, or lazy milk, or boiled milk, is less easily creamed than fresh
milk of ordinarj^ jDroperties. Perhaps also milk, very rich in fat, is
less perfectly creamed than milk containing an average percentage
of fat. These conditions are insignificant, and hardly possess any
importance in practice. They have a perceptible influence in
properly regulated separators only if the creaming takes place at
a temperature under 20° C.

The numerous experiments carried out during the years 1877-1885
at Raden, with different separators, were the first Avhich distinctly shoAved
that creaming is more effective the quicker the separator-drum revolves,
and the warmer the milk is Avhich is to be creamed, and the smaller the
quantity of milk that passes through the drum in a given time. They
showed, hoAvever, that between the percentage of fat (/) in the skim-milk
on the one hand, the rapidity (u) of the drum which determined, on
the other hand, the quantity of milk (m) creamed in an hour, and the
temperature of creaming (t), a certain regular relation existed. Numerous
detailed calculations, which the author has made on the basis of a large
number of single experiments, shoAV that the truth is very nearly obtained
by assuming that the percentage of fat in skim-milk (/) is inversely
proportional to the square of the number (u), denoting the revolutionary
speed, and directly proportional to the square root of the number (m),
denoting the cpiantity of milk creamed in an hour. The relation of the
number (/) to the temperature of cream-raising (t) was foiuid, if (/),
denoting the fat percentage of skim-milk at 40° C, lay between the
limits of 13° and 40" C. by the equation —

and this yields also

/=/,xl-035«-''

(c) indicates a constant factor, which has been obtained for each separator
by means of exact experiments. If the value of this factor has been care-
fully fixed for a definite separator, it is easy, as has been elsewhere shown,
by the author, to find the exact value of (/) for all values of (u) between
^ (u) and 2 into (u), for all A-alues of (m) between (h m') and (2 into
m), and for all values of {t) between 20° and 40° C. In the case of some

144 SCIENCE AND PRACTICE OF DAIRYING.

separators, the author obtained better results if he substituted, in the
above formula, for the square root of (m), simply {m). The above formula
was well suited for the three separators, which were almost exclusively
used up till 1888. As to whether it also suits the Alpha, the Balance,
and the Victoria separators in their present form, the author has not yet
been able to make investigations.

In order always to obtain satisfactory results, the following points have
to be carefully observed in practice : —

(1) That the drum should always revolve at the prescribed rate; to
permit it to revolve more quickly may be dangerous (see § 60), and if it
does not revolve sufficiently quickly there may be a considerable loss.

(2) That the milk to be creamed every day should be of suitable
quantity, and should enter at as uniform a rate as is possible per hour.

(3) That the milk during the whole period of creaming should possess
the proper temperature.

(4) That the separator should always be in good order, and should be
carefully lubricated with good oil.

71. The Supervision of the Revolving Rate of the Drum. — For-
merly the rate of revolution of the drum was shown by an indicator,
Avhich was either in permanent connection with the well of the
drum, or was pressed against the head of the well from time to
time, in order to show if the drum were revolving at the prescribed
rate. This indicator showed how many revolutions per minute the
drum made during the time of observation. For ordinary use, how-
ever, it is unnecessary always to know the exact number of revolu-
tions per minute. It is sufficient to know whether the drum is
revolving at the prescribed speed, or whether the speed is increasing
or diminishing. This is shown by the new indicator, devised by
Dr. O, Brown, of Berlin, which may be directly or indirectly placed
in all separators in a very simple way. As the success of creaming
is influenced, to a large extent, by the rate at which the separator
drum revolves, work should never be carried on without an indi-
cator.

In the case of hand-separators, it is often sufficient to regard the
revolution of the handle as an indication of the prescribed number
of revolutions per minute. This may be effected without using an
indicator by utilizing the swing of a swinging pendulum, the
number of swings of which per minute correspond exactly with the
desired number of the revolutions of the handle. No doubt it is
certain, in the case of hand-separators, that the drum assumes the

QUANTITY OF MILK CREAMED PER HOUR. 145

proper revolving rate only where the handle is properly turned.
The hand-separators whose drum is turned by means of friction
(the hand-separators with falling drums, the Arnold, De Laval, and
the Alpha hand-separator K) should not be used without an indicator.

For exact scientific experiments indicatoi's are necessary, such as those
of Schjiffer and Budenberg — indicators which record exactly the number
of revolutions made by the separator-drum throughout a comparatively
long period.

72. The Supervision of the Quantity of Milk Creamed per Hour. —
Very diflerent quantities of milk may be creamed per hour, in different
separators, and variable quantities of skim-milk, containing different
percentages of fat, may similarly be obtained. In a well-ordered
dairy the aim is to obtain daily an equal quantity, viz. the largest
possible quantity of fat. In order to obtain this, the milk has to be
poured into the drum at an equable rate ; and secondly, the quantity
of milk creamed should be creamed in such a way that the desired
coefficient of cream-raising should be obtained. The first condition
can be satisfied, at any rate approximately, by the use of vessels
with floats. A good vessel should also be arranged in such a way
that one can limit the rate at which the milk runs out, so as to be
able to increase or diminish the quantity running out in the course
of an hour.

The measure of the rate at which milk runs out is discovered
by estimating the amount of milk which is daily creamed per hour.
The percentage of fat in the skim-milk is also determined. Should
it be found that the coefficient of creaming is unsatisfactory, the
rate at which the milk runs in ought to be diminished, until the
skim-milk flowing away shows a percentage of fat of about "25.

The amount of milk creamed per hour is determined as follows: —
When the drum has obtained its full speed, and creaming is ready to be
started, the hour, minute, and second are noted, at which the cock of the
warmer or of the collecting vessel is opened ; and again, the time at which
the last of the milk passes through the cock. The interval is that during
which the whole quantity of milk runs through the drum. For example,
if from 6-17 till 9 •32— that is, 3 hours 15 minutes, or 195 minutes, 260
kilos, exactly of milk passed through the drum of the separator, the
amount of milk which would be creamed in an hour would be

2C00; 60,800 kilos.
195

(M175)

146 SCIENCE AND PRACTICE OF DAIRYING.

In order to obtain a regular flow of milk into the drum of a separator,
one may use a feeding vessel (floating) such as that made at the works of
Lefeldt and Lentsch. It was first exhibited at the second German Dairy
Exhibition in Munich, in October, 1884, and is used in many dairies.

73. The Regulation of the Temperature in the Separation of Milk. —
As the percentage of fat in the skim-milk is very largely influenced
by the temperature at which the creaming of the milk is effected, it is
quite inadmissible to cream milk at the changing temperatures which
it possesses from day to day. Creaming should rather be effected
at a temperature at which it will be maintained throughout the
whole year. This temperature practical experience has shown to be
between 25° and 85° C, on an average 30° C. In the event of one
wishing to cream the milk at 70° to 80° C, for the sake of steril-
izing it, if a definite temperature has been determined, it ought
to be rigorously maintained; and that it varies as little as possible
during creaming should be determined by frequently testing it with
the thermometer. In order to warm milk to the right temperature
warmers are used, which are placed between the milk-collecting and
milk-feeding vessels, and these are best heated with steam.

The cylindrical warmer containing a simple stirrer without brushes, or
warmers in which the milk is allowed to flow over a hot, ribbed surface,
have been found in practice to be successful. Good warmers should be
arranged, as they generally are, so that the milk may quickly gain the
desired temperature, and when this is done the milk should be conducted
without any unnecessary delay into the drum. The shorter the time
required to raise the milk from 25° to 35° C, the more certainly can a
cream and skim-milk of good keeping quality be relied on. If it be
desired, in order to avoid the cooling of cream and skim -milk, to
cream the milk at 15° C., the flow of the milk must be correspondingly
diminished, and the separation of the milk carried on for from 5 to 8
minutes longer. The increased expense by such treatment in dairies
where steam is used, is generally more than that incurred in warming the
milk, and in cooling the cream and skim-milk.

R. Backhaus, the director of the dairy in Fulda and Lauterbach, has
recently recommended that the sterilizing of the milk should be combined
with separating it in such a way, that the milk, at a temperature of 70° to
80° C., coming out of the sterilizer, is immediately conducted into the
separator-drum. Backhaus has been working for a year already at this
process, and he affirms that it gives the best results. This process has
also been in operation in Kleinhof-Tapiau since the middle of February,

REGULATION OF CREAM AND SKIM-MILK IN SEPARATORS. 147

1892. If a percentage of fat in the skim-milk of '25 per cent l>e regarded
as satisfactory, certainly distinctly more milk can be creamed per hour
at these high temperatures than at 30° C, and in this fact another
advantage is to be found.

74, The Regulation of the Relative Quantity of Cream and Skim-
milk in the Use of Separators. — With all separators a larger or
smaller quantity of cream in proportion to the skim-milk can be
obtained at the will of the worker. All that has to be done is to
increase or diminish the amount of the flow of tlie milk to the
drum. In this, however, the degree of creaming varies, a thing
that ought not to be permitted in well-regulated work. For this
reason, the quantity of cream obtained from an equal supply of
milk ought to be able to be regulated at will. In the drums of all
separators, with the exception of the Victoria separator, the neces-
sary apparatus is supplied. In the separators of Burmeister and
Wain, arranged for power use, the regulation is effected during the
flow, and in the other separators such precautions as are necessary
must be taken while the drum is at rest, in most cases before the
commencement of the creaming. If the speed of the flow of milk
does not change, it does not exercise the slightest influence on the
percentage of fat in the skim-milk, whether 15, 20, or 25, or still
higher percentages of cream be taken. It is only when the quantity
of cream is less than 10 per cent of the total weight of the milk,
that the cream is imperfectly separated in the case of some separators.
The cream is obtained thicker and richer in fat the smaller the
quantity. It is not to be recommended to take less than 10 per cent
of the weight of milk, while over 20 per cent should only be taken
if there is some special object, since skim-milk would be lost. As a
rule it is desirable to obtain 15 per cent to 20 per cent of cream.

If there be indicated by (/) and (/,) the percentage composition of the
fat of milk and skim-milk, and by (r) and (b) the relative proportions of
cream and butter obtained from 100 parts of milk, the percentage of fat
in the cream (x) will be exactly found by the folloAving equation: —

and approximately by the equation : —

Bx86

a;:= ,

148

SCIENCE AND PRACTICE OF DAIRYING.

If milk containing 3'3 per cent of fat be creamed at 30° C, the
cream will contain, according as it forms 15 or 20 per cent of the
milk, 19 to 20 per cent, or 14 to 15 per cent of fat.

75. Condition of Cream and Skim-milk from Milk -separators. —
When the work is carried out intelligently, the creaming of milk
by centrifugal force exercises a favourable action on the condition
of the cream and skim-milk; and it has long been proved that it is
easy to obtain butter which comes perfectly up to all requirements

from cream obtained by
means of separators. The
very small loss in material
which milk suffers in cream-
ing, by a small portion of
the nitrogenous matter pass-
ing into the so-called sepa-
rator mud, is, it would seem,
in every respect, and espe-
cially so far as the condition
of the skim-milk is concerned,
quite unimportant. The ob-
taining of fine butter is de-
^c pendent upon the fulfilment
""' ^ of the necessary condition,
that the cream, coming out
of the separator-drum, should
be cooled down as quickly
as possible, to 5" C, by the
application of ice. If the cream be exposed for any length of time
at the temj)erature at which it leaves the drum its condition suffers,
as does that also of the butter into which it is made. Experience
has shown that it is not sufficient only to cool the cream partially
to 12° C. For cooling, cream-coolers of different construction may
be used. Refrigerators which have been largely used and tested
are the Lawrence coolers (fig. 45)— coolers in which the cream
is cooled by being slowly passed over ribbed and comparatively
large metal surfaces in a thin stream, and the Laval cream-cooler
(fig. 46). Skim-milk, unless for use, ought to be cooled down, after
its removal from the drum, to at least 10° to 14° C. It is admirably
suited for use as human food, or for feeding calves and pigs. As it
is very poor in fat, however, it forms only a one-sided kind of food.

Fig. 45. — Lawrence's Kefri^erator.

WORKING OF CENTRIFUGAL MACHINES IN DAIRIES.

Skim-iiiilk, containing only -25 per cent of fat, is not, as a rule,
adapted for making into skim-milk cheese. Nothing is easier,
where there is a demand for skim-milk cheese, than to so regulate
creaming that a skim-milk is obtained with the desired higher
percentage of fat. Skim-milk, when Pasteurized, no longer possesses
the property of yielding a coherent coagulation under the action of
rennet.

There can hardly be any dairies
in which throughout the whole year
there will be a supply of such cold
water at command that the requisite
quantity can be safely enough pro-
vided. For that reason ice cannot be
dispensed with in dairies, and the
necessary supply must be provided.

The precaution of cooling the cream
quickly and thoroughly is one Avhich is
apt to be least recognized in practice,
although it is known by thousands of
observations that cream at warm tem-
pez'atures cjuickly loses its pure taste. It
is only by a happy chance that cream,
which has been kept for some time at a
high temperature, yields good butter.

If creaming be effected at 30° C, it
will be sufficiently near the necessary quantity to give, for every litre of
milk which passes through the drum, -2 to '3 kilograms of ice.

Fig. 46.— Laval Cieani-cooler.

76. The Proper Working of Centrifugal Machines in Dairies. —
Success in dairy management requires that there should be no failure
to provide sufficient and well-arranged rooms, and that the staff' on
the one hand are not overworked, and, on the other hand, that they
observe the greatest care and punctuality.

In every good and well-regulated dairy, separators are used, and in
those in which cheese is not made there should be at least ten rooms. First,
a room for the milk samples; second, for cleaning the vessels and iitensils;
third, for separators and their necessary gear; fourth, for keeping milk,
skim-milk, and cream, with an arrangement for cooling; fifth, for butter-
casks ; sixth, for cream-soiu-ing and the working of butter ; seventh, for the
storage of ice; eighth, for coal storage; ninth, for steam-engines; and tenth,

150 SCIENCE AND PRACTICE OF DAIRYING.

for keeping buttei' for sale. If space be deficient, and if it be required
to limit the room, it may be necessary to unite the milk samples' room
and the room in which the cleaning of the vessels goes on, and to put
the butter-casks and the separators in one room; but the room for the
separators and butter-casks must be large and roomy. Especial care
should be exercised in the choosing of the situations of the rooms for
keeping the milk, skim-milk, and cream, and for cream-souring and the
Avorking up of the butter. The last-mentioned room must be capable of
being heated.

Before creaming is begun, the separators should be examined daily to
see that they are in good working order. During creaming, the supply of
milk, and its temperature, as well as the rate at which the drum revolves,
should be carefully observed for five minutes. It is sufficient to steam the
drums of the separators, along with the other apparatus, once a day, and
to rinse them out with hot and cold water. Furthermore, they should be
treated at least twice a Aveek Avith a warm dilute solution of soda. The
f olloAving points ought to be carefully observed : —

(1) If a separator is not in good Avorking order it ought on no account
to be set in Avorking motion.

(2) The drums of separators should be sloAvly and gradually brought
up to the required revolving speed.

(3) When, during motion, the dri\dng-belts slip off the Avheel, no
attempt ought to be made, under any conditions, to put them on while
the Avheel is in motion. The engine must be stopped before the belt can
be put right.

(4) During the time the machine is in motion the hand ought not to
be laid on it, and the drum should not be touched. This habit may
be A^ery easily acquired in the case of some separators. In using the
separators of Burmeister and Wain, no attempt ought to be made to
remove or to re^Dlace a dish Avhile the machine is in motion.

(5) If, during the motion of the machine, anything unusual happens,
the driAdng poAver ought to be at once stopped, and the same ought to be
done if the drum stops.

(6) Great care ought to be taken Avhen the machine is in motion not
to come near the running belt.

In most dairies in Avhich separators are used the separators are only
used once a day, and the morning and evening milk are creamed together,
perhaps also the forenoon's milk of the previous day, Avhich has been kept
overnight in a special room at a temperature of under 10° C. Practical
experience has shoAvn that the necessary attention can no longer be paid
if the creaming takes more than four hours daily. For this reason the

WORKING OF CENTRIFUGAL MACHINES IN DAIRIES.

151

•luoo'a JO

ajiUKjadiuax

.ipoippopip 1 <p <p
^ CO 6o 1-- oi oi 6o ii io 6i

■-H O

£^'05t^(MCCiu~«oe<D 1 >r5K5

M £ Ah 6

.: t^ O iC 00 (M CO IC

S c>i ip -* CO -^ "TT r:

o o
CO ■5J'

n CO

Percentage Yield.

oi F-lOO<35>-l,-ICl
g ipirjip-Tjiipo-^

h-I

lu: - Cl CO 4l (Tt) r^ 4? f^3

ct-crjGOoocooooooci

: <^
■ 6^

g t_-- to 03 c; 00 -rf ■*
«) «3ihcomt~ir5tb

(3i-li-lrHi-li-Hi-li-l

...
16-54

Actual Yield.

M OiC0C0Tl<rH5O?O
S (Nl-(l-ll-H<NrH,-t

. . CO CO <M 03 -M Ol OS
= .M CI «0 -r O) >r; -(< O

.= = r^ i-H t-H^^ ct '-o i^
5? = -* cT c^" (>f co" (m" oi

20,130
2,876

£ ■to rs .— 1 t^ in -c ^
£ ic o -* o CO CO CO

■; 03-*'J''ft^rrO

(M CO
O lO

juoH

310 Ut P81UB3J0

. r- CI GO lO >-H 1— 1 CO

tico.-i03^or^t^
t^ «o?c-^»ocr>ir5irt

: oo
. o

suoi^jnioAa'a;

o o o o o o o

CO ^^ 02 CO OS Ol CO

CO -.o U-; in lo ^ lo
o" ic in iri" lo vrf >A

o o

(M^CO
CO

Temperature

•c.

csmeoincoco-^iM

a> r-l>-l,-lr-(i-lr-li— 1

00 -^

0> i-i

00 -*
I-H t^

•8U1IX

C»noO(NlOt^O<M 05<»

ao-*mmi>.«o«o m«o

•511! IV
JO X^i^uun^

oo O: CO O CO OJ — ■
oi O 1^ O. 1^ O -* --O

.a i^ o m oo i-H ,-1 (M

I"* \0 0\ Ot oT rp Ci ao"

24,264
3,466

Sunday, 5

Monday, ....6
Tue.sday, .... 7
Wednesday, 8
Thursday, ...9

Friday, 10

Saturday,. .11

: aT

152 SCIENCE AND PRACTICE OF DAIRYING.

number of the separators in use ought to be taken into account. In
every well-conducted dairy, exact details ought to be noted daily and
entered into suitable tables, with regard to all the more important condi-
tions, and also with regard to the success of the Avork. By means of
such details, which permit of the slightest irregularities and their causes
being clearly traced, the Avork attains a high measure of efficiency. The
nature of these details may be best illustrated by the table on p. 151.

If, for example, in the Aveek under discussion, 12,132 kilos, of milk
have been treated and 450 kilos, of butter obtained, there Avould be used
for every kilo, of butter 26 '6 kilos, of milk, or for every 100 kilos, of milk
3-75 kilos, of butter. The quantity of butter (B) Avhich, under ordinary
treatment, can be obtained from milk, Avith an average fat percentage (/),
can be found by the folloAving simple formula: —

B = l-16x/--25; ejj. Bnl-IG x 3-4 - •25 = 3-G9 kilos.

Since, in point of fact, 3-75 kilos, of butter Avere obtained from 100
kilos, of milk Avith 3 "45 percentage of fat, the success of the yield is
thoroughly satisfactory. By means of the formula given, one can calcu-
late, therefore, provided the aA^erage percentage of fat in the milk, Avhich
has been churned, and the yield of butter per 100 kilos, of milk is knoAvn,
Avhether the yield comes up to the required standard or not.

77. The Forces which are brought into Operation in the Action of
Separators. — In dairies in \A-hich 1000 kilos, of milk and more have
to be treated daily, separators are worked only by steam. It may
be generally affirmed that the application of steam pays, if, on an
aA^erage, 800 kilos, of milk are daily treated. If a smaller quantity
of milk has to be treated, hand-separators may* be used, if it be not
possible to form a branch of a co-operative dairy company. In
smaller separating dairies, that is, in those in Avhich 300 to 1000
kilos, of milk are creamed, it is doubtful whether steam or winch or
the application of some minor motor — petroleum or hot-air machine
— is best. There are cases in which the winch is very suitable.
On the whole, however, steam is cheaper, which can be easily
demonstrated if the expenses are exactly estimated, and if it be
taken into account that in the case of the Avincli the cost of
an attendant and one or two horses is incurred. Even the best
winches do not yield their impelling poAver as regularly as is
required for the driving of separators. Steam-engines are most
suitable for dairies in Avhich separators are worked by power, for
the reason that both motor poAver and heat are already there

HAND-SEPARATORS. 153

for use. Small motors, such as winches, only supply power, and
work scarcely cheaper than steam-engines. The conveniences and
advantages of their use do not more than counterbalance their
limited utility. They are, therefore, not to be recommended for
use in dairies.

78. Hand -separators. — Although hand -separators are admir-
ably adapted for use on a small scale, they are, on the whole, of
little importance for extended application. The best course to
pursue in the case of dairying on a small scale, in order to secure
the largest price for milk, to enjoy the advantages of wholesale
trade and capital, and to save time and labour, is the co-operative
treatment of milk supplied by many small cow -keepers, and
carried on in one place under competent direction. It is on this
account that the extended use of hand-separators, even in districts
in which there are excellent small independent farms, is only eco-
nomically justifiable so long as the erection of co-operative dairies,
for various reasons, is not advisable. Under certain circumstances,
they offer great advantages in small agricultural districts in the
neighbourhood of towns, and in small milk businesses carried on
in towns. In country agricultural districts they are employed
generally twice daily, viz. during milking. It is hardly necessary
to say that the separation should not be carried on in the byre,
but should be done in a clean room reserved for the purpose, and
supplied with pure air. The more carefully all precautions which
are advisable in the case of large separators are carried out, the
better will the return be for the large capital invested in them. It
is especially necessary in their case to maintain the prescribed
rapidity of the drum.

79. The Separator Residue. — On the inside of the separators, espe-
cially on the sides of the drums, there is always found, after they
have been in use, a dirty, slimy, highly-distasteful viscous mass,
the so-called separator residue or mud, which can often be taken off
as a skin in large pieces. It is quite erroneous to suppose that this
mass consists simplj^ of the impurities present in the milk. No
doubt it contains all the solid impurities which have come into the
milk, small quantities of food, pieces of dung, hair, bristles, inorganic
mud, and many bacteria and other microscopic organisms. It is,
however, chiefly composed of the constituents of the milk, especially
the caseous matter, which forms about nine-tenths of the weight of
its dry residue. According to the season of the year, the weight of

154

SCIENCE AND PRACTICE OF DAIRYING.

the residue forms '05 to IS per cent of the weight of the separated
milk. The loss of nitrogenous matter which the milk suifers in the
process of separation is inconsiderable, as it only consists of from
•5 to '8 per cent of its entire amount. This loss is of such a kind,
however, that the formula devised by the author for the calculation
of the dry substance of milk from its specific gravity and its percentage
of fat is not applicable to skim-milk obtained from the separator.

Investigations, carried out at different times at Raden, showed that the
fresh separator residues had, on an average, the following composition : —

Water,

67-3

Fat,

1-1

Caseous matter,

25-9

Other organic constituents, ...

Ash,

3-6

100-00

Two analyses made at different times showed the composition of the ash
of the separator residue to be, on an average, as follows : —

Potash,

Soda,

Lime. ...
Magnesia,
Sesquioxide of iron,
Phosphoric anhydride,
Chlorine,

Deduct oxygen replaced by chlorine,

3-155
1-325

45-025
3-361
1-848

43-976
1-691

100-381
•381

100-000

80. Cream. — If the numbers indicating the weight of the cream
and the skim-milk, after the separation of the milk, be added to-
gether, it will be found that the sum of the two is never equal to
the number representing the weight of the milk, since losses occur
through the evaporation of water, the clinging of water to the sides
of the vessels, and unavoidably in the pouring of the milk from one
vessel to another. Where separation is carried on carefully, these
losses in large separating dairies should not exceed 5 to "75 per cent
of the weight of the milk. Investigations carried out on the older
creaming methods, on cream and skim-milk, showed that if water
were allowed to evaporate from the milk during creaming, a distinct
increase in the proportion of protein occurred, with a diminution

CREAM.

155

in the ratio of the milk-sugar to protein, and that the skim-milk
experienced a slight increase in milk-sugar.

The cream obtained in German dairies in which separators are
employed contains, on an average, between 14 and 20 per cent of
fat. Should it be desired, cream containing a larger proportion
of fat can be obtained from separators. It resembles butter, and
contains more than 60 per cent of fat. Comparatively thin cream,
containing 8 to 15 per cent of fat, is commonly known as coffee
cream, and the thicker cream, containing more than 15 per cent,
is known as whisking cream. In other countries than Germany,
for example, in England, the public requires a cream rich in fat.

The great bulk of cream obtained in dairies is utilized for the
manufacture of butter. No doubt cream is used generall}' as an
article of luxury, and forms, especially in town, a much-prized and,
therefore, very lucrative article of commerce. The different names
used for cream are Sahne and Schmand (in East Prussia and the
Eastern Sea provinces), Kern, Flott (in Middle German}^), Schmet-
ten, Obers (in Austria), Nidi (in Switzerland).

Cream chiefly contains the largest of the fatty globules of milk. The
following figures show the chemical composition of cream, and illustrate its
variation in fat: —

Water,

76-6

71-7

66-3

29-0

Fat,

15-2

20-0

25-0

67-5

Nitrogenous matter,

3-1

3-2

1-2

Milk-sugar,

4-5

4-6

4-8

2-2

Ash,

0-6

0-7

100-0

Sp. gr. at 15°C., ...1-017 1014 I'Oll 0-947

The following is the composition of the ash of a sample of cream con-
taining 15-2 per cent of fat: —

Potassium oxide,

28-381

Sodium oxide, ...

8-679

Calcium oxide, ...

23-411

Magnesium oxide,

3-340

Iron oxide.

2-915

Phosphoric anhydi

ide,

21-735

Chlorine,

...

14-895
103-356

Deduct oxygen rey

laced by chlorine,

3-356

100-000

156 SCIENCE AND PRACTICE OF DAIRYING.

The quauLity of phosphoric acid quoted includes that which has been
formed by the burning of the protein bodies containing phosphorus.

The percentage composition of fat (x) of the cream may be found by
the following formula, in which (/) denotes the percentage of fat in the
milk, (f-^) the percentage of fat in the skim-milk obtained, and R the
weight of cream expressed in percentage of the weight of milk, by the

formula given in §74, viz. x= K3 +fij ^^id the percentages of

the quantity of cream E, which must be removed from the milk if the
percentage of fat of the cream is to be obtained as x per cent, is as
follows : — -

100 (./•-/,).

The money value which the cream possesses for the producer can be
easily ascertained. For example: If from 100 kilos, of milk there are
obtained 3-75 kilos, of butter, valued at 2 marks, and the butter-milk is
valued at -02 marks; and it be estimated that 100 kilos, of milk yield
20 kilos, of cream, the following shows the method of calculation: —

3"75 kilos, of butter at 2 marks, ... ... 7"5 marks.

16-00 kilos, of butter-milk at -02 marks, ... -32 ,,

0-25 ,, loss.

20 kilos of cream are worth ... ... ... 7*82 „

According to this calculation, 1 kilo, of cream is Avorth 39 "1 pfennig.
In order to calculate the net value, however, the expenses due to the
preparation of the butter, and the value of the butter-milk, must be
deducted. The market price, as a rule, considerably exceeds the true
value of cream. Cream with 14-20 per cent of fat may, on an average, be
valued at four times the same quantity of milk.

81. Skim-milk. — Skim-milk is a by-product of the dairy industry,
and the small quantity of fat it contains is chiefly in the form of the
smallest fat globules of the milk. In addition to the common con-
stituents of milk, it generally contains small quantities of free lactic
acid. Compared with milk, its composition is more watery, and its
colour appears at average and higher temperatures slightly bluish.
Skim-milk obtained in well-conducted dairies has a specific gravity,
which at 15° C. varies between 1-032 and 1-0365, — on an average,
1 "0345, — and contains, according to older methods of cream-raising,
•8 per cent of fat, and when obtained in separators not more than
•3 per cent. It is used for the preparation of skim-milk cheeses for

SKIM-MILK. 157

human food, and as a feeding material for swine and calves. This
will be dealt with further on. For general purposes, with the
exception of the manufacture of sour-milk cheese, the less free
lactic acid the skim-milk contains the better it is. Skim-milk is,
in the true sense of the word, a food, and belongs to the most valu-
able class of foods. It is obvious, of course, that its nourishing
value is narrower than that of milk, and that it is a one-.sided
food. For this reason it is not suited for the nourishment of
children during their early life. Its value consists solely in the
percentage of proteids, milk-sugar, and mineral salts it contains.
The small quantities of fat which are present are hardly worth
taking into account. The skim-milk obtained by separators is
more valuable than that obtained in the older processes, since it is
characterized by greater cleanliness and freshness.

In feeding pigs with skim-milk, according to the price of meat,
which ranges between 60 and 80 marks per 100 kilos, of live weight,
experience has shown that the kilo, of skim-milk may be taken to
have an average value throughout the j'ear of about 3 pfennig.
If in different places its value is higher, it will be well not to rely
on speculative calculations, but to stick to the above price.

The fresher the skim-milk is which is used as calves' food, and
the more fat it contains, the more nutritive will it be. With regard
to the value of skim-milk in this connection, average figures are
not of much general use. This is owing to the fact that it is strongly
influenced, not merelj" by the breed and treatment of the calf, by
the duration of the feeding, the condition of the market, and the
degree of care which has been bestowed on the young animal, but
also on a condition, which it is not easj' to take into account, but
which has a great influence, viz. the fortune and the individual
o-ood luck of the manag-ement in the treatment of the calves. In
the production of a kilo, of live weight the few experiments which
we have on the subject show that where skim-milk is used as the
sole food for calves, and where the feeding period lasts from 10 to
12 weeks, somewhere about 18 to 20 kilos, is necessary, that is,
somewhere about twice as much as would be required of whole-milk
for the same purpose. It has been often tried, by suitable additions,
to increase the nutritive value of the skim-milk, which has the very
narrow average nutritive ratio of 1 to 1'5. Good results have fol-
lowed the addition of linseed-oil to .skim-milk in order to enrich it
in fat for feedinof calves. Emulsions of fat in skim-milk, which

158

SCIENCE AND PRACTICE OF DAIRYING.

will keep for some time, may be easily prepared with the separator.
In feeding pigs it is possible to increase the nutritive value of
skim-milk by feeding with potatoes at the same time.

Under favourable circumstances, a kilo, of fresh skim-milk, as
a food for calves, may have a value of 3 pfennig. The utilization
of skim-milk as a food for other domestic animals, besides calves
and pigs, is very limited, and we need not deal with it here.

Skim-milk possesses, on an average, the following composition: —

Old method.

Separator.

Water,

89-85

90-30

Fat,

0-75

0-25

Protein matter.

4-03

4-00

Milk-sugar,

4-60

4-70

Mineral matter,

0-77

0-75

10000

100-00

Sp. ST. at 15° C,

1-034

1-035

The analysis of the ash of a sample of skim-milk, obtained by the

separator, is as follows : —

Potassium oxide,
Sodium oxide.
Calcium oxide.
Magnesium oxide.
Iron oxide,

Phosphoric anhydride,
Carbonic anhydride,
Chlorine,

31-634

10-265

21-913

3-115

0-921

19-478

1-000

15-071

103-397
Deduct oxygen replaced by chlorine,... 3-397

100-000

The 19-478 per cent of phosphoric acid includes that formed in the
burning of the proteids containing phosphorus, and the sulphuric acid
arises entirely from the sulphur of the proteid substances.

The value which a kilo, of skim-milk possesses in any district is very
easily determined. If it be known that 100 kilos, of milk, for example,
yield, on an average 3-5 kilos, of butter at 2 marks, and 16 kilos, of
butter-milk at -02 of a mark, the value of the cream will be 7-32 marks.
If the value of 100 kilos, of milk be assumed to be 12 marks, and if 78
kilos, of skim-milk be obtained from this quantity of milk, the value of a

GENERAL REMARKS ON BUTTER-aLA.KING. 159

kilo, of skim-milk Avill be y^^ = 6 pfennig. A kilo, of skim-milk could be
sold at 6 pfennig, which would cover the expense which had, up to that
time, been incurred in the production of the skim-milk in the dairy.

In towns, skim-milk possesses a value which is practically half that of
the same volume of Avhole-milk. A kilo, of lean ox-flesh contains 18 per
cent of protein and 5 per cent of fat, that is, in 100 kilos, there are 2.3
kilos, of valuable constituents. If the nutritive value of protein and fat are
reckoned as equal, and if no account be taken of the value of the remaining
constituents of the meat, and that the cost of 100 kilos, of ox-flesh is 100
marks, therefore the price of a kilo, of protein or fat ec^uals \P^ = 4:-So
marks.

If 100 kilos, of skim-milk contain 4 kilos, of protein and 4-5 kilos, of
milk-sugar, and this latter only worth a fifth part of a kilo, of protein, there
is in the skim-milk altogether 4-9 kilos, of constituents of the value of the
protein. Leaving out of consideration, as of no value, the fat contained in
the skim-milk, if 100 kilos, of skim-milk cost seven marks, the A-alue of
a kilo, of protein is /^ = 1 "43 marks. From this it Avill be seen that a kilo.
of protein in lean ox-meat is three times dearer than in the skim-milk.
Skim-milk, therefore, cannot be too strongly recommended as one of the
cheapest and most serviceable of foods.

82. General Remarks on Butter-making. — Butter consists, as has
already been pointed out in § 4, practically of the fat which is
originally present in the milk in the form of countless extraor-
dinarily small globules. The collecting and uniting together of
the largest possible amount of these fatty globules is effected most
thoroughly by shaking and beating the fluid which contains the
fatty globules — that is, churning — for a time, in vessels specially
constructed for this purpose, viz. butter-churns. The butter may
be directly obtained from the milk as milk butter. By far the
greatest part of the butter, however, which is in daily use, is cream
butter. We have already seen in § 6 that all, or at any rate the
larger number of the fatty globules, present in milk or cream at
ordinary temperatures, are in the fluid condition. Since butter is
separated out as a solid body, it follows that the milk-fat is con-
verted from the fluid to the solid condition by the shaking which it
undergoes while churning. We further know that the fatty globules
are surrounded with milk-serum, and that, owing to the molecular
strain caused in this way on their surface, they are very difficult to
bring into direct contact with each other. Since it has been found
from experience that milk and cream, as soon as souring has taken

160 SCIENCE AND PRACTICE OF DAIRYING.

place in them, are, to a certain extent, much more easily and per-
fectly churned than when in a sweet condition, it must be concluded
that the forces which effect the union of the iatty globules increase
with the greater souring of the milk. When it is considered, how-
ever, that in souring, the condition of the different phosphates
which are j)resent in milk is changed, and in consequence of this the
original chemical condition of the caseous matter, and the nature of
its source, is also changed, it would appear as if chui-ning in every
respect succeeded best after the original condition of the caseous
matter had suff*ered, up to a certain degree, a change in its state of
tenuity. To effect this condition of the caseous matter is the chief
object of the process of souring, by which cream and milk are
prepared for churning. It has hitherto been impossible in churning
sweet milk to obtain even comparatively satisfactory results, and
it is for this reason that in treating milk for butter the milk is
nearly always treated in the sour condition. Sweet cream, if
properly treated, yields a satisfactory quantity of butter, although
less than sour cream. In practice the churning of sweet cream is
only carried out on a very limited scale. By far the largest pro-
portion of butter is made from sour cream.

In churning, butter separates out in round greasy granules,
which on an average are 2 millimetres in diameter, that is to say,
about the size of the head of an ordinary pin. They float about in
the butter-milk, which is a bye-product of the churning. The little
masses which are formed by the union of the small granules may
be called raw butter, in distinction to the finished article, which is
formed by kneading and working up the raw butter. The weight of
raw butter and of butter-milk obtained together never represent
the whole weight of the milk or cream treated, but are always
•5 to 1 per cent less. It is not possible to make into butter all the
fat present in the milk or cream, a small residue, amounting to
2 to 4 per cent of the entire mass of the fat originally present,
remaining behind in the butter-milk, according as to whether milk
or cream has been treated. The manufacture of butter from sour
milk, sour and sweet cream, will be discussed later on.

83. Butter Churns. — The first condition of every butter churn is
that, under proper treatment, thorough separation of raw butter
from the milk or cream should be effected without difficulty, in from
35 to 45 minutes. The more simple and perfect the arrangement of
the churn is for effecting this, the better the churn is. Experience

GENERAL REMARKS ON BUTTER-MAKING. 161

with an endless number of artificial and complicated arrangements
which have been tried in butter churns in the course of time, and
of numberless different methods which have been proposed for
putting the churn in motion, has demonstrated that, the simpler
the construction of the churn, the better it is. The following few
conditions must, however, under all circumstances, be fulfilled: —

(1) The opening for pouring in the milk or cream and for taking
out the raw butter should be as large as possible, so that the churn
may be conveniently cleaned, sufficiently aired, and thoroughly dried.
It is also important that no portion of the inside of the churn be
out of reach of the hand, so that it can be completely cleaned.

(2) The churn must have a simple and sufficient lid to prevent
loss of milk while churning is proceeding.

(3) The churn should be light, convenient, and durable.

It is desirable that a thermometer should be placed in the inside
of the churn, which would indicate the temperature obtaining
during churning.

The best material for butter churns is good wood, free from
faults, of a firm texture (beech, oak, or pine). Churns made of
iron, whether painted or enamelled, are not suitable, and churns
made of white metal, with water-baths, offer no special advantage.
Every new churn must be prepared for use by thorough repeated
washing with hot and cold water. After it has been used it should
be at once emptied, cleaned, and set up to get aired and dried.

Nothing is easier than to make churns which will yield butter
in five or ten minutes' time. Such churns are, however, quite
useless, since they neither yield a satisfactory quantity of butter
nor a butter of good quality.

According to the size of the churn, it is either worked by hand
or by machine. In churns worked by machinery, animal power
and water power are sometimes used, but more generally steam
power.

Churns may be divided into (1) churns with beating action;
(2) swinging, cradle, and rocking churns; (3) horizontal churns, with
dash; (4) vertical churns, with dash; (5) and churns with special
arrangements for stirring the fluid. These chief groups may be
subdivided into other smaller ones, which depend on slight differ-
ences in their arrangement, and are very numerous.

84. Churns. — The churns with beating action have a stationary
barrel, and either one or two beaters. In the churns with one

(M175) L

162

SCIENCE AND PRACTICE OF DAIRYING.

beater the barrel makes a pendulum-like motion during churning.
The most of them are made out of wood. Some of them, however,
are made out of white-metal and other materials. Nearly all the
improvements introduced in this type of churn consist of lightening

the motion of the butt.
They are suited for hand
use for small districts in
which butter is not made
daily, and where it is of
little consequence whe-
ther churning requires
little or much labour.
Formerly they were ex-
tensively used. At one
time they were used even
where butter was made
on a large scale, and
were set in motion by
winches, and in America
even by power.

If we except the fact that the movement of the beaters is tiring,
they discharge their duties very satisfactorily. It is highly probable
that the beating churns are the oldest churns. They can be filled
half full, and the beater, according to the size of the barrel, is made

to give 50 to 100 beats in a minute.
It is not necessary to use a ther-
mometer in the churn.

Some twenty different kinds of
these beating churns are known to
the author, among which the simplest
in use in Germany, Holland, and
America are the churns of Ryerson,
Westman, Lindsay, Gussander, Clifton
(air churn), Pieper, Menken, Holm-
gren, Bailey, Cater, Sayer, Drummond,
Lewi (with a pendulum barrel), Wilson, Zackel, Achenbach,
Ed. Stevens (standard churn), A. Bedros, &c. (figs. 47 and 48).

Cotswing Churn.

48.— Box Churn.

Renne's
Savary,
The best beating churn is the old wooden beating churn of simple structure.

85. Swinging, Cradle, and Rocking Churns. — In all these churns

SWINGING, CRADLE, AND ROCKING CHURNS.

163

the barrel moves, and rolls around an axle, or rocks, or makes both
these kinds of motion at once. They are generally made of wood,
occasionally of white-metal. Those that are in by far the most exten-
sive use are the swinging churns. The cradle churns, which were
formerly much used, are now almost entirely given up, and the
swinging churns are only found in small English and American
dairies. The nature of these churns necessitates the stopping of the
churning from time to time
to permit of the air in the
barrel becoming discharged.
For this reason, the opening
in the barrel is smaller than
is desirable in the interests
of cleanliness and airing, and
the extent of their motion
must not be allowed to ex-
ceed a certain limit. It is
not easy to introduce the
thermometer into the barrel.
These disadvantages, how-
ever, are more than compen-
sated for by the fact that
it is of all kinds of churns
the most easily set in motion
and maintained in motion, a
point of enormous import-
ance in churns for hand use.
In the case of good swinging
churns, the opening in the cask is wide, the taps of the bowls rest on
anti-friction-rollers, and the dashers, when such are present, are so
arranged that they can be easily taken out. Churns of this kind
made after the simplest pattern, as, for instance, the Lefeldt or
Victoria churns, are the best churns for hand use. The swinging
churns do not suit the conditions of large dairying. They cannot
be filled quite half-full, and require, according to their size, 30 to
100 revolutions per minute.

There are a large number of different swinging churns. They are as
follows : —

(1) Those of common construction, in which the barrel is allowed to
revolve round a centre axle; (a) those Avith a Avooden barrel, the churns

Fig. 49.— Dlapliragm Churn.

164

SCIENCE AND rRACTICE OF DAIRYING.

of Muhlstein form, those of Normandy, Lefeldt, J. J. Schmidt, Olivier,
Fouju, Faccioli, Linkler, Eastwood, Bamber, Hathaway, Bradford (fig. 49),
Atkinson, W. Hopperton, W. Waide ; (b) those with barrels made of white-
metal, the churns of Rangod, W. Alway & Sons, and Harrison.

(2) Wooden churns Avhich are moved end over end, that of Burchard,
Victoria churn (fig. 50), and Ahlborn's Triumph churn.

(3) Butter churns
which are moved by an
axle going right through
the cask. The churns
of Tyndall, Midelot,
Thomas & Taylor, and
Julius Hummel. To this
variety belong the Ame-
rican box churn.

Among the cradle
and rocking churns may
be mentioned the rock-
ing churn of AVales, the
French rocking chiu-n,
and the churns of Weisze,
Eberding, C. Seeger, H.
Knappe, Bullard, Da-
vies, Hathaway, Valen-
tine, Landsberg, and A. Geiger (made of glass, for use on the breakfast
table), &c.

86. Churns with Horizontal Barrels. — Although churns of this
kind exhibit great adaptability of structure, they are compara-
tively little used. They are only suitable for hand use, or for use
on a small scale, from the fact that when in use they cannot be half-
filled. They are unsuitable for use on a large scale, or for churning
large quantities of milk, an objection which appertains to all dash
churns with horizontal barrels, and consists in the fact that the
liquid to be churned is easily polluted on its way from the bowl to
the edge of the barrel. It is not easy to introduce a thermometer
into the barrel. On the other hand, there is no objection to making
the opening of the cask very large, and thereby materially helping
the cleansing and airing process. In the case of wood churns of
this kind, the opening of the cask should be wide, the wall through
which the bowl goes sufficiently strong, and the paddles so con-
structed that they may be taken out. In churning, the barrel makes

Fig. 50. — Victoria Cluini.

CHURNS WITH VERTICAL BARREL. 165

75 to 120 revolutions in a minute, and, if a toothed-wheel arrano-e-
ment be employed, even several hundred revolutions in a minute
can be made. Among good solid hand churns with horizontal barrel
may be mentioned those of Blanchard, Petersen, and Hansen and
Spain.

87. Churns with Vertical Barrel. — The dash churns with upright
barrel, of simple construction, are the most admirable of churns for
use on a large scale. If the barrel be conical in shape, it may be
filled to almost two-thirds of the contents of its internal space, so
that these churns are, relatively speaking, the least heavy and un-
handy to work when churning large quantities of fluids. They are
not adapted for hand use, since, in the transmission of movement
by the handle to the barrel, conical-toothed wheels or other force-
destroying apparatus must be used. They are therefore very heavy
to work with the hand. Good dash churns with upright barrel are
constructed in such a way that the dasher may be taken out. The
barrel is provided with a simple pinion arrangement, above which
is a cup for holding oil. The barrel receives 90 to 150 revolu-
tions per minute, according to whether it is milk or sour cream
that is being churned. Churns of this kind, the barrels of which
revolve more quickly, do not last long. Some thirty of these dash-
churns are known to the author.

88. Churns of Uncommon and Special Construction. — Churns of
this kind have unfortunately no value. The experience of centuries
has shown that good butter can only be obtained in the largest
possible amount when separation of the butter from the properly
prepared fluid does not take place too quickly — that is, in somewhere
from 30 to 45 minutes, — and this object can be easily obtained by
the simplest kind of movement of the liquid. It is an idle attempt
to try and eflect an advance in the preparation of butter by intro-
ducing any new kind of motion of the liquid, or by the introduction
of artificial axTangements in the churns, a fact which ought to be
once and for all clearly stated. An example is the lately-exploded
idea that an improvement can be effected b}^ causing movement
by the suction of air into the liquid, as is the case in the churn of
Holland, Francois, & Co.

In conclusion, the following churns may he mentioned, which are
known to the author simply by name: — Weston, ^^^hitelaw, Duchene,
Ransome, Hancock, Pearce, Dashorst, Zimnieiniann, Klaaszen, Loon,

166 SCIENCE AND PRACTICE OF DAIRYING.

Bowler, Fischer, Samson, Seignette, Qudaille, Derlon, Charles, Maugrain,
Penn Helouin, Montslet, Touzet, F. Denis, Destrag, and Turchini.

89. The Practical Value of the Different Churns. — In connection
with this subject a number of opinions have already been expressed
in the foregoing paragraphs, from which it may be inferred that there
is no one absolutely perfect churn — no one churn which, under all
conditions, is equally well suited for butter-making on a large and
on a small scale. For manufacture on a small scale the simple
wooden churn is the best, perhaps a simple wooden churn with a
horizontal barrel. The best churn for manufacture on a large scale
is the so-called improved wooden Holstein churn with upright barrel.

90. The Preparation of the Milk for Churning. — If the liquid is
to be churned in a sweet and unsoured state, which may be the case
with cream, but not with milk, it does not require any preparation.
In the case of churning a sour liquid, the preparation for churning
has as its aim to induce and develop lactic fermentation, in the per-
fectly fresh substance, in such a way that the original condition of the
caseous matter, and with it the condition of the fluid, should become
such, within IS to 24 hours, as to be capable of yielding the best
and the largest possible quantity of butter in a good condition and
of uniform quality. In practice, cream is often, and milk is always,
left to become sour of their own accord, and in that way the yield
of butter is left to chance. Such treatment is to be condemned as
thoroughly uneconomical. When the fluid has obtained the condition
which experience has shown to be most favourable to churning,
it is known as ripe for churning. Ripe milk should be uniformly
gelatinous (thick as the liver, as the farmers say), and ripe cream
should be uniformly leathery. For the purpose of judging of ripe-
ness there are no indications or infallible tests. It is only to be
known by practice and experience. If the liquid has not quite
gained a sufficient degree of ripeness before churning, the result is
that less butter is obtained, and if the degree of ripeness be
exceeded, the nature and keeping quality of the butter suffer. To
obtain ripeness in a longer or shorter period than from 18 to 24
hours has been shown to be risky, since under such conditions
uniform ripeness can scarcely be expected to take place throughout
the entire mass of the liquid. In the case of ripeness obtained in a
shorter period, it is scarcely possible to note daily the most suitable
time for churning, as the condition of the fluid changes so quickly;

PREPARATION OF THE MILK FOR CHURNING. 167

and in the case of ripening more slowly, the cream or the milk is
exposed longer to all possible accidental sources of injury than is
desirable in the interests of the keeping quality of the butter.

In order to efiect ripening in from 18 to 24 hours, the liquid
should be placed in large vessels of wood or of white-metal, in a
warm and easily ventilated room with a northern exposure. The
lactic ferment should be added in sufficient quantity to produce the
necessary sourness. The milk should be gently stirred from time
to time with a suitable stick made of good wood, and the vessel
may either be slightly covered or be open as desired. The milk is
to be maintained at as uniform a temperature as possible, whicli
may vary between 15" and 20° C.

Formerly butter-milk from the previous churning was almost univer-
sally used as a sourer. This is still often done, and such a method is all
right, provided the butter-milk contains fairly pure lactic ferment, which
is capable of producing a rapid development of lactic acid. As soon,
however, as other ferments crowd out the lactic ferment in the butter-
milk, a state of matters which may easily occur in summer, the milk
may become seriously affected. The cream may become caseous or the
butter may become oily, a state of matters Avhich may last for months,
since the sourer is always obtained from the butter-milk of the previous
churning. This may be avoided if, as is now generally done in all well-
conducted dairies, the sourer be prepared fresh every day. This may be
effected in the following way : —

A small quantity of milk or skim-milk is allowed to sour. This should
not be more in amount than 6 per cent of the total quantity to be sub-
sequently soured. After lactic fermentation has become well developed
in this portion, it is used as a sourer. For this purpose small metal bowls
are used, similar to the Swartz bowl. They are covered wath felt, placed
in a wooden box in clean dry straw, and after they have been filled they
are covered with a close cloth. In the bowls the milk or skim- milk,
which, according to circumstances, has been heated to a temperature of
from 20° to 30° C, before being poured out, is alloAved to stand for 24
hours in some place Avith a pure atmosphere. Sweet skim-milk, obtained
by the Swartz or separator method, is more suitable than milk, because
no cream is formed upon it, and there is no fear, therefore, that the
susceptible milk-fat on the surface of the liquid will become tainted
during souring, and impart a bad flavour to the liquid to be soured.
Since skim -milk sours more slowly than whole -milk, on the surface of
which a dense laj-er of cream quickly forms, the sourer is generally
produced fi-om whole-milk. In this case no time should be lost in tasting

168 SCIENCE AND PRACTICE OF DAIRYING.

the cream formed during souring before using it, and discarding it if it
possess the slightest flavour. The quantity of sourer used should not
exceed at the most 5 per cent of the liquid to be soured. It is better to
use only 2 per cent, or even less, for cream, as it is only with cream it is
used, since milk which is to be churned is allowed to sour itself, and the
temperature of the cream should be raised somewhat during souring,
within the limits already mentioned. These limits, which are 16° to
20° C, must be rigorously maintained, since experience has shown that
the security of the manufacture is endangered if these limits be exceeded,
either above or below. There is no necessity to exceed these limits, since
the margin which they give, though apparently a narrow one, is sufficient
at every season of the year to regulate the temperature of the cream so
that it may safely ripen in from 18 to 24 hours. Eipening is either
hastened or retarded by bringing the temperature of the cream for a
shorter or longer period nearer to the higher or lower limit. By a diligent
and regular observation of the temperature of the souring of cream, by
frequently tasting it, and, above all, by carefully Avatching the progress
of the souring, an amount of knowledge and experience can be readily
gained by means of which successful work is secured much more surely
than by repeated and exact determination (chemical) of the lactic acid in
cream. By too little soui-ing the yield suffers in quantity, but only to
a slight extent, while the quality is not at all impaired. On the other
hand, in the case of too much souidng, a yield of good butter is impossible.
Especial care should be taken, therefore, that the cream is not allowed to
become too ripe — that is, too sour.

There are no practical experiments to show Avhether the cream-souring
effected by lactic fermentation can be replaced by artificial souring by
means of lactic or acetic acid. It is also very difficult by the latter means
to effect in an equable and perfect manner the ripening of the fluid to be
churned. That is best eftected by lactic fermentation taking place equally
throughout the whole mass. If the butter possessed any blemish which
can be traced to the disturbed development of the souring of the cream,
pure cultures of lactic ferments should be at once obtained for souring
the Pasteurized cream, and such pure cultures should be used until it is
possible to again obtain a good sourer, by allowing the milk to become
spontaneously sour. Such pure cultures of lactic ferment can now be easily
obtained at the dairy experiment stations. By regularly Pasteurizing the
cream, the yield of a uniformly good butter is greatly promoted.

91. Churning. — The changes which take place in the churn
during churning, from the solidifying of the fat of the individual
fatty globules of the milk, to the appearance of the little lumps of

CHURNING. 169

butter about the size of pin-heads, and the individual circumstances
whicli influence the firmness and percentage of water in the texture
of the raw butter, are theoretically little understood. Up till now,
on this account, the rules for churning have been exclusively drawn
from practical experience alone.

Butter of the best quality, and possessing the best keeping
properties, contains, as experience has shown, not more than 15 per
cent of water. It is neither soft nor oily, nor on the other hand
hard or friable, but possesses an average degree of softness and a
characteristic texture of grain, by which its origin from countless
quantities of individual globules and small lumps of hard fat can be
easily recognized under the microscope. Butter of this uniform quality
can only be obtained when churning is carried on neither too long
nor too short a time, and neither too slowly nor too quickly. The
best results are obtained when churning lasts for f roui thirty to forty-
five minutes, a period which is only limited by the exact violence
of the movement and the exact temperature of the liquid which is
being churned. Within certain narrow limits the violence of the
motion is in inverse proportion to the height of the temperature, so
that with a more or less powerful movement the same effect can be
produced as can be effected by a corresponding increase or decrease
of temperature. The art of making good butter from good ripe
milk or good ripe cream consists solely, for the above reasons, in so
regulating the temperature of the liquid for each individual churn,
and for the churns of different kinds, that the production of the raw
butter is effected in the prescribed time. Butter receives its texture
and its consistence in the churn during churning, and defects
which are produced during churning can be by no means sub-
sequently removed.

The obstacles which retard the union or the coalescence of the butter
globules to form the lumps of fat are decreased Avith an increase in
the temperature of the fluid; and the more violent the motion, even to
such a degree that heat is produced, the more easily are they overcome.
It may be pointed out that where churning takes place too quickly, either
through too high a temperature or too violent a movement of the fluid,
the little lumps of raw butter do not separate out easily, but include,
besides the solidified fat, fatty globules which are in the liquid condition.
The author is further of opinion that the little lumps of fat take
up more butter-milk, in the form of small microscopic drops, the more
quickly they are formed. If the little lumps of butter contain liquid fat

170 SCIENCE AND PRACTICE OF DAIRYING.

which is only solidified by the subsequent treatment of the raw butter, and
which becomes smeared between the previously solidified fat, the granula-
tion of the texture is partly injured, and the finished butter must show a
soft smeary condition. In a similar manner butter which has taken up too
much liquid in the churning will be soft, and will contain an unusually
high percentage of water, since, even after long-continued treatment, only
a small quantity of this water can be driven out, because it is present in
the butter in such a fine state of division.

If churning does not take place satisfactorily within the prescribed
time, it is an indication that the temperature is not suflBciently high, or
that the motion is not sufficiently violent. If the temperature is found to
be higher at the conclusion of the churning, it cannot be expected that the
little lumps of the raw butter will be of uniform nature. It is more pro-
bable that in such a case, owing to the weak motion in churning, they will
include much liquid fat, and that owing to the final quick churning they
will contain unusually large quantities of butter-milk. Experience shows
that oily butter is obtained by too quick, as well as by too slow churning.
Not only, however, does the quality of the butter suffer in such a case;
but the yield of butter is also diminished. The motion of the liquid in
the churn is ahvays closely connected with the development of tempera-
ture. The quicker the motion, the more does the temperature, which the
liquid originally had, rise, a fact Avhich has to be reckoned with in churning.
The rise of temperature in churning sour milk or cream should not
exceed 1° to 2*5° C. In the properly-conducted churning of sweet cream
an increase in temperature of 3° C. or even more has been observed.

As a result of experience, the following points are worthy of attention: —
In the first place, the ripe milk or cream is weighed and brought up
exactly to the temperature Avhich, from experience, it is known ^Wll effect
churning in from thirty to forty -five minutes. This temperature is not the
same for similar fluids in each place and for each kind of churn, or even in
the same place and for the same churns throughout the year, but A'aries
according to different conditions. The size, the special arrangement of the
churn, especially the speed with which the fluid is churned, the quantity
of the fluid in proportion to the cubic contents of the churn, and the
season of the year, will all influence it. The imparting to the fluid of the
proper temperature is best effected by pouring it either partly or entirely
into a metal vessel, and keeping it there in water of 30", or at most, 35° C,
as long as is necessary. Small differences in temperature can be most
effectively equalized by the so-called cream boxes, which are filled with
warm or cold water. These boxes, filled with ice, are excellently suited in
summer for cooling a liquid to be churned. After the fluid, Avarmed to a
proper degree, has been poured into the churn, its temperature is again

CHURNING. 171

taken, in order that the fall in temperature due to the changing from
vessel to A'essel may be counteracted. Churning is then started. During
churning nothing must be done to regulate the temperature. The
temperature of the fluid should be observed, however, and also the first
appearance and the gradual development of the lumps of butter. As
soon as the lumps have assumed the proper size, churning is at once
stopped. The lumps of butter are then washed from the paddles and
the sides of the churn, with pure, previously boiled and sufficiently cooled
Avater, or with skim-milk, for which purpose a small pouring watering-can
with a rose should be employed. The butter is then taken out of the
churn with a hair-sieve, and is freed from the greater portion of the butter-
milk which remains clinging to its surface, by dipping it while in the
sieve several times into pure cold, previously boiled water. The remainder
of the fluid, which adheres to the surface of the butter, is removed as
thoroughly as possible in the subsequent treatment of the raw butter.
Finally the mass of butter obtained has to be weighed, and it has to be
calculated how many kilos, of milk have been recpirecl to produce a kilo,
of butter, or how many kilos, of butter have been obtained for every
100 kilos, of milk. If the butter be salted, it is generally weighed in a
fresh condition, before salting, in order to determine how much salt it will
be necessary to rub in. The temperature at which churning begins is as
follows : —

For sweet cream, ... 11'25° to 15° C, on an average 13-125° C.
For sour cream, ... 1250° to 20° C, do. 16° C.

For sour milk, ... 15° to 21-25° C, do. 18-125° C.

In the most successful experiments, it has been found that in the case
of sweet milk subjected to unusually violent churning, the process of
churning should begin at 7-5° to 8-75"", on an average 8-125° C. Milk or
cream from the milk of milking-cows long calved, since it is more difficult
to churn than the milk or cream of milking-cows recently calved, must be
set for churning at a higher temperature. The author has found that
cream from milk of milking-cows long calved must first be brought to
24° C. before it can be churned. As is to be expected, the yield in respect
of quantity and condition of butter is not very satisfactory.

If, owing to any oversight, the proper temperature for chiu-ning a
liquid has not been chosen, the error may be rectified in exceptional cases
by adding warm or cold boiled water. In the application of such a remed}',
which is always hazardous, it is especially important to see that only
absolutely pure water, heated at the most to 40° C, is used.

No substances can be added to the liquid to be churned which facilitate
churning or improve the butter. The so-called butter powder, which is

172 SCIENCE AND PRACTICE OF DAIRYING.

often advertised, contains, as its chief constituent, sodium carbonate, and
perhaps also alum or salt or saltpetre or annatto, and consequently can
only act as a neutralizer of the acid, or impart to the butter a higher
colour. Among the harmful substances added occasionally, with male-
volent intent, to a liquid to be churned, are soap-lye, sal ammoniac, even
small quantities of which retard or render churning quite impossible.
Sugar-gum, lime, spirits, meal, crumbled bread, to which a harmful action
has been also ascribed, have no bad effect if added in small quantities.

If in winter the ' room in Avhich churning is to be carried on is not
warm, or in summer is not cool enough, the churn should be cooled or
heated, before churning, A\ath hot or cold boiled water.

If the butter has to be coloured, the butter colour should be measured
in proper proportion, and cautiously mixed Avith the fluid in the churn
immediately before churning is commenced, so that none of the colour may
come into contact with the wood of the churn and thus be lost.

A daily register of the initial and final temperature of the liquid and
the length of time of churning ought to be kept, and this register ought to
furnish a useful table of reference for judging of the speed of motion.

So far as the author is aware, it has not been attempted to churn daily
and regularly in one churn more than -400 kilos, of liquid.

92. Churning of Sour Cream. — Sour cream is comparatively more
easily churned, and yields, when the souring has been properly done,
a butter which possesses the best keeping properties. The tempera-
tui'e at which churning begins varies, under ordinary conditions,
between 13'75° and iToO" C. In large dairies the Holstein churn of
improved construction is almost exclusively used, and the churn is
worked at the rate of from 110 to 120 revolutions per minute.
The quantity of cream which is churned in this chum must be at
least large enough to stand 10 centimeti-es above the lower cross-
piece of the fly-wheel of the churn, and must not be, on the other
hand, so large that it stands more than a similar height above that
point. During churning, which should be completed in from 30 to
at the most 45 minutes, the temperature of the cream ought not to
be allowed to rise higher than from 1° to at most 2*5° C.

93. Churning of Sweet Cream. — Butter made out of perfectly
sweet faultless cream possesses the pure taste of butter, free of all
foreign flavours, and is the finest butter which can be made. Since,
in churning sweet cream, the souring of cream, the development of
which is attended with so much labour, inconvenience, and uncer-
tainty, is quite unnecessary, it is highly desirable, from a practical

CHURNING OF MILK. 173

point of view, that sweet-cream churning should become general.
Even although sweet cream is not so easy to churn, and j'ields
always, even under the most favourable circumstances, less butter
than sour cream of a similar percentage of fat, yet this is amply
compensated for by the great advantage which is offered by being
able to dispense with cream-souring. The fact that, notwithstanding
this, sweet-cream churning is at present only practised to quite a
slight extent, is chiefl}' to be accounted for by the fact that by far
the larger majority of consumers prefer the light aromatic flavour
of butter made from sour cream, and that only a few know how to
appreciate the fine flavour of sweet-cream butter. In the year
1874 the director of the manufactory for making preserved butter
in Copenhagen, Herr Busck, junr., put himself to a great deal of
trouble to introduce the churning of sweet cream into the dairy
districts of Denmark -And South Sweden. For several years this
movement seemed to make good progress, but even as early as
the year 1882 this method of butter manufacturing was being
given up, and at present, so far as the author is aware, in all
dairies where sweet-cream butter was formerly made, sour cream
is now again churned. The careful experiments carried out in
Denmark at that time showed that the yield of butter from sweet
cream, when the improved Holstein butter churn was used, was only
2 or 3 per cent less than that from sour cream containing a similar
percentage of fat, provided the sweet cream was churned at an
initial temperature of 11 '25° to 12 "50° C, and the churn was worked
at the rate of about 150 revolutions per minute, churning being-
carried out in 25 or at the most 30 minutes. The butter-milk left
behind from sweet-cream churning assumes very commonly, in a very
short time, a bitter acrid taste, which becomes especially distinct if
the butter-milk be slowly warmed. This is probably to be traced to
the action of certain kinds of bacteria, which can develop in liquids
showing an amphoteric or neutral reaction, but not in those possess-
ing an acid reaction. Even in sweet-cream butter, which has been
kept for some time, a bitter flavour is often found in addition to the
rancid flavour.

94. Churning of Milk. — As has already been pointed out in § 90,
it is not economical to churn absolutely sweet milk, since it has
not yet been found possible to obtain from it even approximately
the same quantity of butter as is obtained in the churning of
sour milk. As a rule, milk 24 and 3G hours old is churned, viz.

174 SCIENCE AND PRACTICE OF DAIRYING.

the morning milk of the one day and the evening milk of the
previous day. The milk is poured into large wooden vessels, or
cylindrical metal vessels, to the depth of about 60 centimetres in
summer, and in winter somewhat higher — about 75 to 80 centi-
metres, and is allowed to become spontaneously sour, but is not
treated with the sourer. When it is churned the milk should not
have become liver-thick, that is, it should be in a condition between
the firm and the liquid condition. If the Holstein churn is being
worked, the churn should be revolved at the rate of about 100
revolutions per minute, and the initial temperatures should be
within the limits of 15° to 18'75° C, so that the churning may be
finished within 45 or at most 60 minutes.

The churning of milk requires very little space and very few utensils.
It makes a small demand on the technical knowledge of the dairy staff, and
offers generally, on account of its extreme simplicity, great advantages. On
the other hand, it affords only a one-sided utilization of milk. Although it
occasionally yields a very fine butter, milk-churning, on an average, pro-
duces a butter inferior in quality to that from cream-churning. The butter-
milk must he vised either as a food for pigs or worked into curds, or into
sour-milk cheese. Formerly this method of utilizing milk was very
general, and was very popular owing to its simplicity; at present it is
becoming less and less so, and it can scarcely be regarded as economical,
except under very exceptional conditions.^ In no country in which dairying
is in a recognized forward condition is milk-churning carried on to any
extent. How old this method of butter manufacture is it is difficult to
discover. This much, however, is known, that in the previous century it
Avas in use in different districts of Belgium, Holland, and probably also
Northern France.

The yield of butter in the churning of milk is somewhat less than it is
in the churning of sour cream obtained by separators, and somewhat higher
—as in the proportion of about 100 to 102 — than in the churning of sour
cream which has been obtained by the older methods.

95. Experiments made to Obtain Butter by Methods other than
those Commonly in Practice. — During the year 1889 two new kinds
of apparatus were brought out, by means of which butter was made
under conditions essentially different from those obtaining for
centuries, in the manufacture of butter. These were the Butter

1 In certain districts in Ireland and in Scotland, especially in mining districts, where tliere is a good
demand for butter-milk for human consumption, this method of treating milk is regarded as the most
remunerative. — English Editors.

BUTTER-SEPARATORS.

175

Extractor of Jacobson, first exhibited at the Royal Agricultural
Society of England Show at Windsor, from the 24tli to the 29th
June, 1889; and in Germany first at the Provincial Schleswig-
Holstein Exhibition at Kiel on the 20th to 23rd March, 1890; and
the Butter Separator of Dr. De Laval, first exhibited in Germany
at the Fourth International Exhibition of the German A2:ricultural
Society at Strasburg in Alsace from the 5th to the 11th of June,
1890. Both of these machines cream the milk by centrifugal force,
and immediately churn
the cream thus obtained;
and in both, the arrange-
ment for churning is of
such a nature, that the
cream is beaten with extra-
ordinary violence. In the
butter-extractor (fig. 51)
the cream is separated on
the spot in the inside of
the separator-drum, and
in the butter-separator the
cream leaves the separator-
drum in the usual way,
flows over a cooler, and
falls thence into a small
open butter cylinder at-
tached to the separator
frame or stand. The bowl
of this butter cylinder is
set in motion by means of

a spring from the bowl of the drum. As is well known, the tempera-
ture at which creaming of milk takes place is not the same as that
at which churning is done; since the most favourable temperatures
for the separation of cream and for churning are not the same.
The arrangement of the butter-extractor is of such a nature that
creaming must take place always at that temperature which is
required for churning, while, on the other hand, in using the butter-
separator there is nothing to prevent the regulation of the tempera-
ture in a suitable manner to what is best suited to promote the
success of the successive processes. From this point of view, there-
fore, this apparatus possesses an advantage over the former. As has

Fig. 51.— Ceutrifugal Butter-separator.

176 SCIENCE AND PRACTICE OF DAIRYING.

been previously mentioned, butter should leave the extractor at a
temperature of from 20° to 21° C, and the butter-separator at a tem-
perature of from 16° to 17° C. In the small butter cylinder of the
butter-separator, the paddle apparatus of the separator, when work-
ing at its most favourable speed, makes 3600 revolutions per minute,
and in the butter-extractor the rate of revolution is still greater.

The author has seen the butter-extractor repeatedly in operation,
but has not been able to examine it minutely; on the other hand,
he is familiar with the w^orking of the butter-separator. According
to his observation the extraction of butter by this apparatus
differs from the ordinary ojDeration of churning in the following
points : —

(1) In the butter-separator, the separation of butter is carried
out by means of a mechanical arrangement, which is more violent
than that used in the ordinary churning.

(2) The formation of the little lumps takes place much more
quickly than in the ordinary processes of butter production.

(3) The little lumps of butter do not attain to the same size as
in the ordinary processes.

(4) The cream is only subjected to the mechanical action for a
short time.

The real service which the butter-separator performs consists in
the fact that it renders it possible to churn perfectly sweet cream,
and to obtain excellently satisfactory results in proportion to the
quantity. Although this service is an important one, it can scarcely
be said to mark an important advance in the practice of dairying.
This would only be effected if it were shown that the new apparatus
yielded butter, the properties of which complied with the require-
ments of technique, of commerce, and of flavour. The experiments
carried out by the author have shown that the little lumps of butter
3'ielded by the butter-separator retain far more butter-milk than
those little lumps obtained in churning in the usual way, and there-
fore that the butter of the butter-separator is, on an average, some-
what more watery than ordinary good butter. Even although the
butter-milk could be more perfectly separated from this kind of
butter, a point which does not seem to be unattainable, the butter-
separator would still probably only have a limited use, since there
is a very slight demand for perfectly sweet butter prepared from
perfectly sweet cream, owing to the fact that the public taste in
Germany does not lie in that direction.

COLOURING OF BUTTER FOR USE. 177

96. Colouring of Butter for Use. — The requirements of a whole-
sale trade, which has to provide throughout the year a good butter
of uniform appearance, has brought about a demand which in the
course of time has given rise to the practice of adding suitable
substances to butter to impart a definite uniform colour. Formerly
it constantly varied in colour. This requirement is burdensome
and inconvenient to dairies, but it must be complied with so long as
the large dealers in the finest butter for export purposes will only
pay the best price when the butter possesses the required tint.
Butter which is used for home consumption is not coloured, and it
is stupid, and serves no end, to colour it with pigments such as the
so-called butter colours.

The following qualities are necessary in a butter colour, viz.
that it should colour the butter yellow without imparting to it a
foreign taste or smell, that it should contain no substances deleterious
to health, that its appearance should not be non-appetitizing, that it
should be easy to apply, that it should possess strong colouring
properties, and that its price should be in proportion to its true
value.

In the Hamburg market, the butter going to England lias to possess a
yellowish straw colour, and that going to Spain and Portugal, and also a
part of that going to South America, has to be orange yellow. Formerly,
in butter exported to different countries — to France, Holland, and North
Germany — all sorts of colouring matters were added, such as saffron,
carthamus, logwood, turmeric, carrot-juice, extract of marigold, and annatto,
which were generally added to the butter by kneading in. At present,
where butter is colovired, it is generally done in the churn, and the liquid
in the churn receives an exactly measured quantity of the colouring matter
directly before churning, which is without doubt the most efficacious way.
The colouring matters used in Germany, Denmark, and Sweden are
entirely solutions of the fruit flesh of the annatto tree, indigenous to South
America and the East Indies, dissolved chiefly in hemp or sesame oil, and
with varying quantities of turmeric colouring matter added to the solu-
tions. In using this kind of colour, for butter destined for England, on
an average about 4 grams are required or added for every 100 kilos, of
milk, or for the cream yielded by this quantity of milk. The butter con-
tains, therefore, reckoning 3-5 kilos, of butter for every 100 kilos, of milk,
•12 per cent or 1-2 gram of colouring matter per kilogram; that is, assum-
ing that none of the colouring matter is left behind in the butter-milk.
As this, hoAvever, is always the case, the butter used in the English market
contains on an average about 1 gram of colour per kilogram. If the price

(M175) M

178 SCIENCE AND PRACTICE OF DAIRYING.

of a litre of artificial colouring matter be taken at 4 to 5 marks, the
colouring matter used for 100 kilos, of butter will cost about 80 pfennigs.

97. Salting of Butter. — Over the whole of South Germany,
Switzerland, and in the countries of the Austro - Hungarian
monarchy, the butter is not salted. On the other hand, in North
Germany, Denmark, Sweden, England, Holland, and in some dis-
tricts of France, salt butter is chiefly used. The quantity of salt
added differs — that used for immediate consumption containing
1 to 3 per cent, that used for export containing generally 4 to 5 per
cent, sometimes, however, more, even as much as up to 10 per cent.
The object of salting is to preserve, render the butter better, and to
impart to it a flavour — the salt flavour. By means of salting, raw
butter is more thoroughly separated from the butter-milk which
adheres to it than it would be possible without the application of
salt. Four to five per cent is quite enough to ensure for butter
keeping properties that are sufficient for all practical purposes.
Good butter salt should not only be pure, but should also possess
the proper degree of fineness, and should be rapidly soluble in water.
Butter salt of too coarse a grain does not dissolve perfectly in the
moisture of the butter, and too small grains form small drops of brine
which are difficult to incorporate by kneading. It is obvious, of
course, that the salt kneaded into the butter is not to be wholly found
in the finished butter, since a large portion of it becomes dissolved
in the water used in the kneading, and is thus lost. Raw butter, to
which 4 per cent of salt has been added, contains, when properly
kneaded, scarcely 2 per cent. The liquid expressed by kneading
contains, according to investigation, about 90 per cent of water, '15
per cent of protein matter, '6 per cent of milk-sugar and lactic acid,
and 9'25 per cent of mineral matter, exclusively salt. During salting
and kneading, the raw butter suffers, on an average, a loss of weight
of from 2 to 4 per cent; indeed, under exceptional circumstances,
the loss may amount to as much as 9 per cent.

If butter salt has to be tested for its usefulness, it should be chemically
examined for purity and tested by means of the microscope. It should
be of a pure white colovir and free from mechanical impurities, and when
dried should contain from 98 to 99 per cent of sodium chloride. Salt with a
musty smell or mixed Avith sand, or containing several per cent of gypsum
or sodium sulphate, calcium chloride, and magnesium chloride, and which
in consequence absorbs moisture rapidly from the air, is not suited for

THE WORKING AND KNEADING OF BUTTER. 179

salting butter. To further examine it, three sieves of different meshes of
2, 1, and "5 mm. in diameter are used to determine its fineness. Its
apparent specific gravity and relative solubility should also be determined.
The salt best suited for salting butter is that Avhich consists of not too small
but very thin and delicate crystals. Such salt is largely composed of
little pieces, Avhich remain behind on the coarsest sieve, exhibit a relative
small specific gravity, and dissolve rapidly in water. In North Germany,
the butter salt coming from Lunniberg and Stade is rightly much
appreciated.

In England, Sweden, and America, in order to give to the butter
greater keeping properties, it is common to add not salt alone to the
butter, but also a mixture of salt and sugar, or a mixture of salt, sugar,
and saltpetre. Since, however, as has already been pointed out, it is
possible to impart to butter the desired keeping quality by the addition
of salt alone, all other substances, sugar excepted, must be regarded as
inadmissible.

98. The Working and Kneading of Butter. — The object of
working butter is to unite the countless little lumps, of the size of a
pin-head, formed in the raw butter during churning, and to remove
the butter-milk clinging to them as perfectly as possible. It is also
desired to convert them into the finished product, which shall
possess a similar texture throughout and be in the best condition
and of irreproachable appearance. This is best effected by artificial
pressing and turning during the working of the single lumps formed
in the raw butter. The working is sometimes associated with
washing butter. In the preparation of salted butter, the effect of
working depends upon the fact that each grain of salt attracts
moisture from its surroundings, which dissolves it and forms a
larger drop of brine. The working of butter will be understood,
when it is remembered that on the one hand every single grain of
butter contains a larger or smaller quantity of small drops of butter-
milk, according as churning has been more or less successfully carried
out, and that, on the other hand, a certain quantity of butter-milk
mechanically clings to the surface of every single little grain. The
butter-milk enclosed in the little grains of butter is in far too fine
a state of division to permit of its being diminished to any extent
by working, even although this may be carried on for some time.
At most it may be perhaps somewhat diminished by the osmotic
action which salt exerts. On the other hand, it is very easy to
remove the butter-milk clinging to the external surface of the little

180

SCIENCE AND PRACTICE OF DAIRYING.

lumps, and this should be done as effectively as possible. As soon
as this is effected butter should no longer be worked. A longer
period of working is not only useless, but is even deleterious, since
it influences in an injurious manner the characteristic structure pos-
sessed by good butter. The art of working consists in expressing

the butter-milk contained in
the butter into large drops,
in such a manner that they
unite together, and then by
so turning it that the drops
formed in this way flow out
owing to their gravity. The
formation of large drops is
effected by making number-
less deep impressions for a
sufficiently long time on the
pieces of butter. It is quite
a mistake and is useless to
press the butter on all sides
at the same time, in working
it, or to squeeze it out in thin
layers, or to treat it in any
other way violently. The
most excellent kinds of
butter contain not less than
10 and not more than 15 per cent of water. Overworked butter,
that is, butter which has been too long and too powerfully kneaded,
possesses a stale dry appearance; and butter, when insufficiently
worked, is soft and oily.

The operation of working should always be effected entirely —

and this would be best, — or chiefly

#i'i.i :■ . : M . ■ i..,„.„^^^^ ,iii,iiii i.,,,1, 1 ,ii.i.,;ife|iai iiiii,!^^^^ with butter -workers (figs. 52

Fig. 53.— Butter-knife. and 54) instead of with the hands.

There is quite a large number
of such utensils, of which several are not quite suited for the pur-
pose, as, for example, the butter-syringe of Handcock and Von
Bohlken and others, the Eureka butter-worker, the Reid butter-
worker, and the Swiss butter- worker, all of which fall far short of
what is required. Only two butter-workers can be recommended
as well suited for their purpose, and as meeting in a satisfactory

Fig. 52.— Butter-worker.

THE WORKING AND KNEADING OF BUTTER. 181

way the requirements of such utensils, viz. the utensil invented

Fig. 54.— Butter-worker.

Fig. 55. — Holstein Butter-worker.

in America and improved in Denmark and Germany, with ribbed
roller moving in a circle over a round table (fig. 55). This utensil

182

SCIENCE AND PRACTICE OF DAIRYING.

is adapted for use on a large scale. The other one is also American,
and has been improved by Amsinck, and consists of a kneading-
board, and is suited for use on a small scale. The apparatus recom-
mended by the Frenchman Baquet, which separates the raw butter
from the butter-milk in a centrifugal apparatus specially adapted
for the purpose, by means of centrifugal force, has on careful inves-
tigation not been found to be generally suitable.

The work of kneading is best carried on when the butter has a
temperature of from 10° to 15° C. The room in which the butter
is kneaded must therefore be kept cool in summer and heated in
winter.

Washing the butter thoroughly during kneading affects its
fineness, perhaps also its keeping qualities, and can only be justified
if the souring of the liquid which has been converted into butter is
not pure, or has been carried too far.

A proved method of working in the production of salted keeping butter
is the following: —

The raw butter is separated by taking pieces weighing from 1 to 2 kilos,
gradually from the churn, and placing them in the mould-shaped beech-
wood butter-trough (fig. 56),
after the butter-milk has run
away of its own accord. The
first piece is laid on the side
of the trough, and a pressure is
Fig. 50. -Butter-trough. api^licd with both hands, one

laid on the top of the other.
The flatly-pressed piece is rolled together and placed upi'ight, and this is
repeated six or ten times. This is repeated Avith each remaining piece till
the whole mass is entirely worked and the first kneading is ended, there-
upon the thoroughly -kneaded butter pieces are brought to delicate scales
placed in the kneading-room, weighed, the necessary quantity of salt ac-
cording to the weight is added, that is, for every kilo. 20 to 40 grams, or
2 to 4 per cent of dry good salt is added, and the weighed-out quantity of
salt is mixed in a graduated glass cylinder. The half of the pieces of
butter are then brought into the upper part of the butter-trough, half the
salt is strewn thereover, the other half of the butter is then added as an
upper layer, and this is strewn with the other half of the salt as uniformly
as possible. It is scarcely necessary to say that, according to circumstances,
the butter may be mixed with the salt in three or more layers. Similarly,
it is hardly necessary to mention that when the butter is to be kneaded
the hands should be first warmed and then Avashed in cold water. As

THE WORKING AND KNEADING OF BUTTER, 183

soon as the salt has been strewn, pieces weighing from 4 to 5 kilos, are
gradually added from above in successive layers, and a strong pressure,
made by pressing with the one hand on the top of the other, is applied eight
or nine times on the side of the trough. Before every new pressure the
piece which has been pressed flat is changed to different sides, and pressed
again in order to incoi'porate the salt in the most thorough manner possible.
When the Avhole mass has been thoroughly worked, salting and the second
kneading is at an end. The single pieces of butter are left in the trough
lying beside one another, from 4 to 6 hours, and are not further worked
with the hand, but only with a butter- worker or with an American butter-
board. A single working on the butter-board at the end of the proper
time is sufficient. If the pieces of butter as they come from the working
in of the salt lie beside one another and not on the top of one another, the
whole mass of the butter receives a similar consistence. If the butter
should be too soft in summer, the proper degree of firmness may be
imparted to it by cooling it in a suitable method from above with ice. In
winter the butter-working should be carried on in a heated room. If the
butter is too cold in winter it should be placed in a metal vessel on a damp
board, and laid in water at 15^ or 16° C. until it has received the necessary
amount of softness for working. If the butter has to be worked later on
in the kneader, it should be spread in portions or layers not too thick over
the table, after being prepared by being treated with sufficiently hot or
cold water, care being taken that the holes for permitting the draining
away of the butter-milk are not choked up. When the butter-worker is
not fitted up for machine use, kneading should be carried on by two
persons, one turning the handle at a medium rate, and the other, by means
of a wet wooden spatula, spreading the strips of butter on the board of the
worker as soon as it has passed once through the rollers, in pieces of about
30 centimetres long. These are subjected to a uniform rolling for a
quarter of an hour and again placed in the pressing rollers. This rolling
and pressing must be carried out with care, in order that the liquid drops
on the butter may flow away and be separated. The operation may be
regarded as finished as soon as, after strong pressing together of pieces of
butter about the size of the fist, no more drops of brine are seen, which is
generally the case after the whole mass has passed eight or ten times through
the rollers. The room in which the butter lies after salting must be fresh,
clean, and free from dirt; care also ought to be taken that the butter
should not be exposed for a long time to the action of bright daylight. In
summer-time, it is occasionally advisable to cover with gauze the trough
in which the butter is lying. The butter should be packed away in the
previously prepared box or tub as soon as possible, on its removal from
the kneadinff-board. It is advisable not to touch the butter with the

184 SCIENCE AND PRACTICE OF DAIRYING.

hands during working, but to carry out the first and second kneading on
the butter-worker.

99. Yield of Butter. — Of a very large number of churns which
have been constructed and recommended in the course of time,
only a very small number have succeeded in establishing them-
selves in general practice. With all the useful churns, if properly
handled, a yield of butter can be obtained from a fluid, which
approximates to the percentage of fat it contains. This explains
how the amount of the yield of butter in proper churning is almost
always solely dependent on the percentage of fat in the milk, and
on its successful removal in the cream. From experience, and a
large number of experiments, it is known that it is easily possible
to obtain about 97 per cent of the entire fat in the form of butter
when sour cream containing 15 to 25 per cent of fat is employed;
89 per cent when sour milk is used, and 86"5 per cent when sweet
cream of 15 to 25 per cent of fat is employed. If the percent-
age of fat in milk be denoted by the letter /, and the finished butter
contains 84 per cent of fat, the yield of butter x, in the case of
churning with sour milk, may be easily obtained by the following

formula : —

a; = l-06 x/

and in the case of churning soured cream, when the percentage of
fat in the skim-milk obtained is "25 per cent, by the formula: —

a;=1.155x/- .2454.

It would be very simple and easy to calculate similar formulae
for other cases. Such formulae are extremely important and useful
for occasional testing of the results of the manufacture of butter in
dairies. By calculating the yield of butter, for example, in the
case of a known percentage of fat in milk, and by comparing the
result obtained with that actually yielded in practice, it is shown
whether what is, as a rule, easily obtainable, has been really obtained
or exceeded, or whether, owing to existing unfavourable circum-
stances, it has not been obtained.

In practice, the yield of butter is generally found by weighing the
butter obtained, and by dividing the number denoting the weight of the
milk used by the number denoting the Aveight of the butter. In this
way we learn how many parts by weight of milk have been required
for each part of butter by weight obtained. By dividing the number

DIFFERENT KINDS OF BUTTER. 185

denoting the quantity of milk into 100, or by looking up in the author's
tables the number standing beside this number, the percentage yield of
butter is obtained. In dairies in Avhich butter is salted, the butter is
■weighed always after the first working, and before the salting, for the
purpose of estimating the proper quantity of salt to add; and this figure
may be used for estimating the yield of butter. Since butter in the
unfinished condition generally contains somewhat less fat than the finished
article, the yield of butter will be found to be somewhat higher in this
way than by weighing the finished article. In a properly conducted dairy,
the creaming of milk and churning should be carried on throughout the
year in a similar manner, so that any variation in the yield of butter
should be due to the variations in the percentage of fat in the milk and
to the season of the year. On this account, if in such dairies the per-
centage of fat in the milk to be worked aproximates very nearly to the
amount of the yield of butter, care should be taken not to draw an exact
conclusion from these grounds, but also to take into account, in judging
of the percentage of fat in the milk, the results given by the butter-
testing apparatus.

100. Different Kinds of Butter. — Butter, in the first place, may-
be distinguished as milk -butter and cream-butter, according as it is
obtained from milk or cream. Milk-butter is prepared from sour
milk, while cream-butter may be further divided into butter made
from sweet cream and butter made from sour cream. Since there
are still few dairies in which separators are used, butter coming
from such dairies is known as separator-butter. It would be desir-
able that such butter should be designated by a particular name,
since it is regarded as inferior to that made by the old — that is,
the Holstein — method. Finally, butter may be distinguished as
fresh butter and keeping butter, unsalted butter and salt butter,
and coloured and uncoloured butter. The following kinds of butter
may be distinguished in the butter market: —

(1) Fresh Butter or Table Butter, Tea Butter, &c., adcqjted for
immediate consumption. — Such butter contains either no salt at
all or only very small quantities. It is either entirely uncoloured,
or in winter-time slightly coloured. The finest kinds of this butter
are prepared from perfectly fresh sweet cream, and it is neither
salted nor coloured. The so-called Petersburg butter or Paris
butter, which was formerly chiefly prepared in Finland, is unsalted
cream-butter, possessing a characteristic, not unpleasant, light taste.
By means of the peculiar treatment which the cream used in its

186 SCIENCE AND PRACTICE OF DAIRYING.

preparation undergoes, it possesses keeping qualities in a very high
degree. The cream, before churning, is heated to the boiling
temperature of water, or approximately to that heat, when it is
rapidly cooled and churned in the ordinary way. Naturally, it is
only perfectly sweet cream that could stand such treatment.

(2) Preserved Butter, or butter prepared from milk or cream, is
always salted, and generally also always coloured, and is expected
to retain its pure flavour for four weeks or longer. Such butter is
suited for export to England, and for transhipment by sea to other
countries. The butter which keeps best is made from soured liquid,
especially soured cream, since in it, through the action of the lactic
bacteria, all the remaining kinds of bacteria are retarded in their
development, and since, owing to its sour reaction, a large number of
deleterious kinds of bacteria are entirely prevented from developing,
so that as a result of this the fat is only changed by gradual oxida-
tion. Good preserved butter should only become rancid with the
lapse of time, but should not develop any other flavour, such as a
soapy or bitter flavour. In the Hamburg butter-market, butter is
distinguished as winter or byre butter and summer or grass butter.
The winter butter is divided into old-milk and fresh-milk butter,
and the summer butter into May, early-summer, late-summer, and
stubble butter. The best-keeping kinds are the early-summer, late-
summer, and especially stubble butter. That which is not exported
to foreign countries comes upon the market in casks and barrels
of wood, which in certain large European butter markets must be
of a certain prescribed size and quality.

Butter which is prepared for provisioning ships, and for export
to other parts of the world, has been known since 1873 as preserved
butter. This kind of butter is not prepared in any special manner,
and is not treated in any way, but simply consists of selected
quantities of fine butter, which, in the judgment of competent
butter experts, may be expected to possess, with great probability,
good keeping qualities. This butter is always salted, and occasion-
ally, although not frequently, is treated, in addition to salt, with
sugar and saltpetre. It is always coloured. It is packed in air-
tight, soldered, round, metal barrels of diflferent sizes, which hold
from 1 to 23 kilos, of butter, and which are generally coloured
outside with aniline colour.

In Bremen, Hamburg, Kiel, Copenhagen, and Stockholm, and in other

DIFFERENT KINDS OF BUTTER. 187

European ports, large butter manufactories supply preserved or box
butter for transatlantic shipment. One of the earliest and most important
undertakings for supplying such butter was that founded in 1873 in
Copenhagen, under the directorship of Mr. Busck, viz. the Scandinavian
Preserved Butter Company. The activity of this excellently conducted
business exercised during the period of its existence a widespread influence
on the dairy industry of Denmark and of South Sweden. To such an
extent was this the case, that for several years only butter Avas put on the
market which had been made under the ice system from sweet cream
which had stood for 10 hours, and in consequence the practice of SAveet-
cream churning was carried on for a time to a considerable extent.

The transmission of table butter in post-boxes, or in boxes by post,
which do not hold more than 5 kilos, nett, to private consumers, has
developed very considerably in Germany during the last ten years.

The different names applied to the difierent kinds of butter which are
used in the retail trade, as, for example, hurst butter, lackierte butter, gold-
brand butter, &c., are of comparatively little importance.

(3) Whey Butter. — In all districts where fatty hard cheeses are
prepared, for example, in South Bavaria, in Switzerland, in Austria,
and in Holland, butter is obtained from the whey, which contains
a small portion of the milk-fat which has not been removed in the
manufacture of the cheese. Separation of the fat from the whey
may be effected in three different ways. The whey may either be
warmed to 68° to 75° C, treated with 1 per cent of sour whey,
and further warmed to 80° to 95° C, skimming the fattier portion
of the so-called vorhruch, which at this temperature collects on the
surface, and amounts to about 3 per cent of the entire volume of the
whey; or the whey may be allowed to stand 24 hours in cold water to
cream, and the rich fatty surface layer may then be skimmed off;
or the whey creamed by the separator, as is done with milk. Both
the vorhruch and the whey cream are churned in the ordinary
manner. The whey butter obtained from whey cream is better than
the vorhruch butter. Butter obtained in the latter way represents
a lesser yield than butter obtained in the former waj". It may be
calculated that in the preparation of fat cheeses, according to the
Emmenthaler method, "75 kilos, of vorhruch butter is obtained from
every 100 kilos, of milk, and '8 to 1 kilo, of whey butter. Both
these kinds of butter do not differ in their average composition
(chemical) from ordinary butter. Possibly they are often a little
richer in protein bodies. In fineness and pureness of flavour they

188 SCIENCE AND PRACTICE OF DAIRYING.

are no doubt distinctly inferior to ordinary butter, and this is more
so the case with vorhruch butter than with whey butter. These
two kinds of butter are often not churned alone, but mixed with
cream or milk, the butter obtained being of average quality.

101. Melted Butter. — The butter obtained by the melting of
butter-fat, melted butter, forms throughout the whole of South
Germany and Austria a very important and much-sought-after
article of commerce, which has long been in use. Good, pure melted
butter contains 98 to 99'5 per cent of butter-fat. The best kinds are
obtained by melting good butter on the water bath at 40° C, allow-
ing it to remain for several hours at this temperature until it becomes
perfectly clear, and then carefully skimming the foam or scum which
collects on its surface, and separating it from the sediment by pour-
ing it off. The scum and the sediment furnish a useful fat for
kitchen purposes. In the preparation of melted butter on the large
scale, a loss of from 17 to 20 per cent on the butter used is experi-
enced, and on a small scale 20 to 25 per cent. Occasionally, in tlie
preparation of melted butter on the large scale, difficulties arise, such
as the failure of the butter-fat to solidify when slowly cooled, the for-
mation of a liquid, and of a solid part, which separates out from the
liquid portion, the so-called butter-oil obstinately remaining liquid.

AVhat is known in the Hamburg butter-market by the name of Siberian
butter, is melted butter which is brought from the interior of Russia via
Archangel and St. Petersburg.

102. Butter-milk. — The fluid left behind after churning — the
butter-milk — contains chiefly the smaller fatty globules of the milk,
and possesses a specific gravity which is somewhat higher than that
of ordinary milk, varying between 1'032 and 1'035 at 15° C. It
appears, according to the method of churning, either perfectly fresh
or more or less sour. Sour butter -milk, on account of its weak
seedy condition, closely resembles in appearance poor cream, or
very rich fatty milk. Butter-milk, made from sweet cream, easily
assumes an unpleasant bitter flavour, which is especially developed
when the butter-milk is warmed. Butter-milk obtained from proper
churning contains as a rule from '5 to '6, in no case more than "8 per
cent of fat. Common practice, which still favours to a large extent
the unseemly custom of pouring in large quantities of warm or cold
water into the churn during churning, often yields butter-milk of an
exceptionally poor percentage of fat.

THE PROPERTIES OF GOOD BUTTER.

189

Butter-milk is chiefly used for feeding pigs. It is also used in
small quantities for cheese manufacture and as a human food. Its
feeding value is very difl'erent, according as it has been more or less
watered. Unwatered butter-milk can occasionally be sold for the
feeding of pigs under the most favourable conditions at 3 pfennig
per kilo. It is pretty near the truth to say that, taking the value
of pork at 35 to 40 marks per 50 kilos, of live weight, its feeding-
value may be estimated at 1'5 to 25, on an average at 2 pfennig
per kilo. Very sour butter-milk should be boiled before feeding,
especially if used for calves, and should not be used in too large
quantities at once, but rather oftener, — four to five times per day, —
in small quantities. Its nutritive ratio is about 1 to 1'5.

The average composition of butter-milk and of its ash will be seen from
the following analysis : —

Water, 91-24

Fat,

Protein,

Milk-sugar and lactic acid, . . .

Ash (mineral matter),

Composition of the ash : — ■

Potassium oxide,

Sodium oxide.

Calcium oxide,

Magnesium oxide, . . .

Phosphoric acid,

Chlorine,

Iron, sulphuric acid, and loss

•56

3-50

4-00

•70

100-00

... 24^53

11^54

... 19-73

3-56

29-89

13-27

0-47

102-99

2-99

100-00

Deduct oxygen replaced by chlorine,

103. The Properties of Good Butter. — Good butter should possess
a uniform appearance, neither patchy nor striped. Its colour, which
is influenced by the feeding, and perhaps also by the individuality
of the cow, is in winter yellow, occasionally almost pure white, but
in summer it is yellowish to absolute yellow. In artificially coloured
butter, an entirely yellow or reddish-yellow tint is required in the
different markets. Good butter should neither be dull nor entirely

190 SCIENCE AND PRACTICE OF DAIRYING.

sparkless in appearance, but ought not to possess too strong a
glitter. It should have a tender, mild glitter, which it has when it
possesses the characteristic ripe grain, which distinguishes it from
all other fats. In properly prepared butter the exceedingly fine
division which the fat originally possesses in the milk should not be
entirely lost, but should be distinctly recognizable. To this may
be ascribed the fact that butter-fat is very easily emulsified by the
gastric juices, a characteristic that distinguishes butter-fat from all
other fats, and renders it easily digestible. Good butter should
neither be too soft, that is to say, smeary and of the nature of a
salve, nor too hard, that is, dry and friable. The drops of moisture
and of salt brine present in butter should not be too large nor too
abundant, but must be quite clear, and should not possess in the
slightest degree a milky appearance. Salted butter should not
contain undissolved salt.

The smell or odour of butter is in close relationship to its flavour,
and should only be very slightly developed in good butter, and then
it should be of a pure characteristic butter odour.

The flavour of good butter should be that of pure butter only,
and should not be associated with any kinds of foreign or unusual
flavours. Apart from the fact that salt butter is distinguished from
unsalted butter by its salt flavour, butter possesses an essentially
different taste, according as it is prepared from sweet or sour liquids.
Butter made out of sweet cream is characterized by a clean, extremely
mild, and by no means strong flavour; butter made out of sour
liquids possesses a certain aroma and a powerful characteristic
flavour, which in many districts is demanded as an absolutely
essential quality. Regarding the origin of this aroma, so far as is
known up till now, it can neither be traced to the food, nor is it
already formed in the milk. It seems to be first formed during the
process of souring, in consequence of the change and the mutual
decomposition of the constituents of the milk, probably of the milk-
sugar, and its origin is connected with lactic fermentation. Whether
perhaps some of the neutral fats present in butter are decomposed
at the beginning of the decomposition, and whether lactic fermen-
tation alone is its cause, or whether it is not also connected with
other kinds of fermentation, as, for example, alcoholic and butyric
fermentation, is not altogether yet fairly demonstrated. We know
nothincr with refjard to the chemical nature of this aroma. Peters-
burg or Paris butter has a weak flavour of boiled milk.

THE COMMON FAULTS OF BUTTER. 191

Butter made from the milk of cows that have been in milk for
a time is generally firmer than that from the milk of recently
calved cows, and usually possesses also a less fine flavour. With
regard to the influence of the feeding of the cows on the condition
of the butter, it has been proved that colour, smell, flavour, keep-
ing qualities, and in a very special degree the solidity of the butter,
are dependent on the properties of the food consumed by the cow.
In a much greater degree, however, the condition of butter is in-
fluenced by the treatment of the milk before churning, by the kind
of churning, and by the method in which the raw butter is worked.
These conditions have a greater influence than the food.

In addition to the above-mentioned points, the appearance, the
smell, the flavour, the solidity, the fat percentage, the quantity, and
the condition of the brine of the butter and its keeping qualities,
have all to be taken into account in judging of its condition. The
condition of butter depends on the condition of the milk, as well as
on the method of treatment, the feeding of the cow, on the lactation
period, probably also on the breed, the individuality, and the age of
the cow, but above all on the method in which the butter is manu-
factured.

In order to test the firmness of butter, it is repeatedly pressed with
the flat side of the blade of a knife, and a piece is cut off in order to see
whether the butter sticks to the knife. By pressing, it is easy to obtain for
inspection a drop of brine. If the flavour of butter be desired to be tested,
a small piece is taken with a perfectly clean knife, spread on the small
finger of the free hand by means of the other hand, lifted to the mouth,
not with the knife, left a short time on the tongue, and then swallowed,
the butter being pressed against the gums in the act of swallowing. If
preserved butter tasted, after 8 to 14 days, perfectly pure and fine, and if
it possessed the proper appearance and grain and the required firmness,
and especially if the brine be perfectly clear and not in too large a
quantity, it may be asserted with a high degree of probabihty that it will
keep excellently, and that it is suited for use as preserved butter, that is,
for packing for export in metal boxes. Butter A^ith milky brine may
possess all other good properties, but it never keeps long.

Although Ave know little for certain Avith regard to the special action
of individual foods on the condition of butter, the remarks Avhich have
already been made in § 18 may be regarded as worthy of attention.

104. The Common Faults of Butter. — The undesirable properties
which are observed in butter are for the most part caused by

192 SCIENCE AND PRACTICE OF DAIRYING.

mistakes made in the preparation of it, and are only due, to a
small extent, to the use of foods unsuitable for milk -cows. These
properties or diseases develop in a very characteristic manner in the
keeping of preserved butter. The following are the indications of
bad butter, which are recognized on the larger butter markets, as,
for example, in the Hamburg market.

The butter is described by the following terms : —

Faults in A2')pearance. — If it contain milky brine, dull and cheesy; if
too much worked, opaque and thick; if glittering with fat, because it has
been spoiled in the churn or has been too little worked, fatty or oily; and
in the case of coloured and salted butter, apart from the proper shade of
colour that it ought to possess, flechj, streaked, cloudy. These faults are
the result of unskilful colouring or salting, or working the butter in
winter in unheated rooms.

Defects in Firmness. — Dull Avhen soft and rich in milky brine; oily, too
soft, overivorked, dry and hard, burned, that is, dry and friable, and short
or crumhling.

Defects in Flavour and Smell are as follows: — Rancid or hitter, terms
that are used respectively according to the weaker or stronger develop-
ment of the flavour; dull, rank, bitter, uninviting, greasy; lardy when there
is a weak tallow flavour, and tallowy when there is a strong tallow
flavour. The butter is inclined to develop this flavour if the cows eat
much young fresh clover, or if they be supplied with large quantities of
tallowish-flavoured oil-cakes. Furthermore, the butter becomes tallowish
if it lie for a long period in bright light, or if it be submitted for a short
time to the sunlight. Butter, also, which has been frozen and again thawed
is occasionally tallowish; oily when it is accompanied with a strong
development of this quite peculiar characteristic flavour; fishy and with
the flavour of train-oil. The oily flavour, which only butter made out of
soured liquid assumes, is characterized to a certain extent by an increase
of the peculiar aroma belonging to this kind of butter, which finally
becomes positively repugnant. It is caused by certain kinds of bacteria,
which develop, along Avith the lactic ferment, during souring, especially
in summer. As soon as it is noticed a sourer (pure) should be added,
preferably a pure culture of lactic ferment for souring the cream. Woody,
that is, spoiled by the boards of the kegs in which the butter is packed.
The woody flavour, which is somewhat distantly suggested by the peculiar
after -flavour of Roquefort cheese, is only developed if moulds grow on
the surface or in the inside of the butter. This defect is engendered by
packing the butter in casks made out of young damp wood inclined to be
musty, and also by not compressing the butter firmly enough into the

THE CHEMICAL COMPOSITION OF BUTTER. 193

casks. Cheesy, possessing a bitter acid sour flavour of the country; an
unclean oldish flavour which is not very characteristic. Tasting of the food,
generally bitter, and caused by undue feeding of cows with certain kinds
of foods, such as cabbages, frozen or otherwise damaged beet-root, sour food,
distillery refuse, &c. ; tasting of the lyre, Avith the flavour of cow-dung and
the atmosphere of the byre; smoky, if ovens in the rooms in which butter
is kept are bad and smoke; soapy, caused by careless washing of the dairy
utensils with soap or soda ; smelling of oil-paint, if grease has been brought into
contact with the cream or butter, or if the milk has been kept in vessels
freshly painted with oil-paint; and musty, if the butter has been kept in
damp, badly-aired rooms.

Other defects are mouldiness, if the butter be white, green, grass-green,
or red, owing to bacterial growth; blue, from blue milk, very uncommon;
oversalted; defective salting, if the finished butter still contain grains of
salt; and lastly, dirty, if the butter contain threads, hairs of cows, dead
flies, soot, &c., or shows patches of rust, or generally gives indications
of dirty handling.

105. The Chemical Composition of Butter. — The chemical com-
position of butter varies according to the method in which it has
been manufactured. Nevertheless, under all circumstances, milk-
fat or butter-fat is its chief constituent. Like all other common
milk products, butter contains all the constituents of milk, and if
its fat be left out of consideration, it contains the other constituents
in the same proportion as they are present in milk. Butter may be
described as a kind of solid milk. It is owing to the fact that it
contains, in addition to the fat, a certain quantity of water and a
small quantity of protein matter, milk-sugar, and the mineral salts
of milk, that it is what it is. In milk of average chemical compo-
sition, there are for every 100 parts of water 4 parts of albuminoids,
5'2 parts of milk-sugar, and "85 parts of the mineral constituents; so
that the proportion of the quantity of water on the one side, and
the sum of the above-mentioned constituents, in addition to the fat,
is in proportion of 100 to 10"1, or roughly 10 to 1. Taking the
percentage of water in properly-prepared butter as on an average at
15 per cent, it must contain on this account '6 per cent of protein,
•8 per cent of milk-sugar, and IS per cent of mineral salts. In the
process of thorough washing or salting with 4 per cent of salt, and
after powerfully w^orking it, the quantity of protein matter, and
even to a greater extent also the milk-sugar or the lactic acid in the
butter, is diminished.

( M 175 ) N

194

SCIENCE AND PRACTICE OF DAIRYING.

When properly manufactured, the raw butter from the churn,
after being passed through a hair sieve and before being worked,
contains about 16 to 22 per cent of water, and between 76 and 82
per cent of fat. In the preserved butter of commerce the quantity
of the individual constituents very rarely exceeds the limits of the
following percentages : —

Limits for the percentage of water,

,, ,, fat,

Other organic constituents,
Limits for the percentage of ash (not including 1
the salt added), ... ... ... J

7 to 16 per cent.
80 to 91
-8 to 2

-1 to -28 „

The best kinds of butter contain not less than 82 per cent of
fat, not more than 15 per cent of water, and not more than 2 per
cent of the other constituents, exclusive of the added salt.

Pure butter is a bad nourishing medium for micro-organisms.
The more nitrogenous matter the butter contains, the more favour-
able is it for the growth of bacteria and moulds in and on the
butter. The keeping qualities of butter especially are in danger,
if decomposition bacteria have developed, during souring, in the
liquid churned, and infect the butter.

The average chemical composition of the finished article is indicated
by the following analyses : —

From Sweet Cream and

From Sour Liquid

without Salting.

Salted.

Unwashed. Washed.

Water,

.. 15-00 15-00

12-00 12-50

Fat,

.. 83-47 83-73

84-75 84-62

Protein matter, . . .

.. 0-60 0-55

0-50 0-48

Other organic matter,

.. 0-80 0-60

0-55 0-40

Ash or ash and salt,

0-13 0-12

2-20 2-00

100-00 100-00 100-00 100-00

The specific gravity at 15° C. is, on an average, -9437 for unsalted butter,
and -9515 for salted butter. The melting and solidifying point of butter
are approximately the same as those which were given in § 6 for pure
butter fat.

As an example of the chemical composition of the pure ash of butter,
the following results give the composition of the ash of unsalted, unwashed,
and well- worked butter made from sour cream : —

THE INVESTIGATION AND TESTING OF BUTTER.

195

Potassium oxide, ...

Sodium oxide,

Calcium oxide,

Magnesium oxide,

Phosphoric anhydride.

Chlorine, ...

Iron, sulphuric acid, and loss.

Deduct oxygen replaced by chlorine,

19-329
7-714

23-092
3-287

44-273
2-604
0-288

100-587
0-587

100-000

The quantity of phosphoric acid quoted above includes that formed by the
burning of the phosphorized lecithin.

106. The Investigation and Testing of Butter. — Ordinary chemical
analysis of butter offers no special difficulty. If butter is to be
tested for adulterants, the methods used in determining its chemical
composition are for the most part not available. The processes
used for this purpose are of a special kind. In such a test of butter,
what is sought for is the presence of (1) deleterious colouring mat-
ters; (2) preservatives; (3) unusual quantities of water, or of foreig-n
solid bodies which have been added to the butter for the sake of in-
creasing its weight; and (4) foreign fats. The substances mentioned
under Nos. 1, 2, and 3 demand difficult and complicated methods of
investigation, so that tliey can only be carried out by a chemical
specialist. On the other hand, it is easy to detect adulteration of
butter with water, which is the most common of the above-men-
tioned adulterants. This method of adulteration is easily effected
by melting unsalted butter in hot water, and by stirring up the fat
with the water; or by working unsalted butter in salt water, or
working salted butter with fresh water. The weight of the butter
can be increased by this action to the extent of 26 per cent.
Owing to the wide extension of the trade in margarine, and its
use as an article of consumption, as well as the custom of selling
margarine as butter, the investigation of butter for foreign fat, or
the difference between butter and other fats, is especially important.
The most valuable methods of research used for this purpose, are
based upon the fact that butter-fat contains a number of neutral
fats, with volatile easily-soluble fatty acids, forming on an average
about 8 to 9 per cent of its weight, which in other fats are either

196 SCIENCE AND PRACTICE OF DAIRYING.

entirely absent, or are only partly present and in very small
quantities. The proportion of the quantity of volatile to the non-
volatile fatty acids found in the fat tested is correspondingly deter-
mined by one or other of the methods. If this proportion were
invariable in butter-fat, it would be possible to detect the smallest
possible quantities of foreign fats in butter. Since, however, it
varies within comparatively wide limits, the case with regard to the
testing of butter is almost the same as with regard to the testing
of milk. Adulteration in small quantities is as difficult to detect in
this case as in the former. No doubt, under very special unfavour-
able circumstances, such as very rarely occur, butter may contain
20 to 25 per cent of margarine adulteration, and the adulteration
cannot be proved by investigation. On this account, in addition to
the determination of the quantity of volatile or non-volatile fatty
acids, a number of other tests for butter-fat have been applied.
Thus, for example, there is the determination of the specific gravity
of the fat at the boiling temperature of water with a margarimeter,
since it has been observed that most of the different kinds of fat
show a lower specific gravity than butter-fat. This method of
testing is, however, only valuable in the cases in which the mar-
garimeter shows a lower specific gravity in the fat investigated
than that of butter-fat, since various vegetable fats, such as earth-
nut oil, sesame oil, and poppy oil, have the same, or even a higher,
specific gravity, than pure butter-fat. It has further been recom-
mended to determine the coefficient of the fracture of the fat at
a certain temperature, by means of a refractometer, since it has
been found that pure butter-fat has a less high fracture coefficient
than most of the other kinds of fat. The fat should also be
tested in polarized light by means of a 75 linear enlargement, owing
to the fact that the fat from melted margarine, on cooling, assumes
a kind of crystalline structure, and exhibits characteristics in
polarization, which butter-fat does not show, even although it has
not been somewhat equally melted and again cooled. It is not
possible to refer to the many different proposals for the detection
of adulteration which have been made in addition to those above-
mentioned.

In the testing of butter for the detection of substances which are not
fat, the centrifugal butter-tester of Lefeldt is useful, as it renders the
investigation easier, and points quickly to the discovery of suspicious
butter. Up till about 1870, it vras not possible to distinguish butter-fat

THE INVESTIGATION AND TESTING OF BUTTER. 197

with certainty from animal-fat. The discovery of the Hehner method
rendered this possible. In this method, the fat to be tested, after being
prepared in a pure solution, is saponified, the soap thus obtained is decom-
posed, the soluble and insoluble acids separated, and the total weight of
the palmitic, stearic, and oleic acids estimated. The sum of these three
insoluble fatty acids varies in pure butter-fat from 85 '5 to 89*8 per cent,
and rarely exceeds in all the rest of the fats 95 "5 of the total fat investi-
gated. A simple and much-used method, based upon a similar principle
as the Hehner, is the Reichert. It Avas first somewhat changed by
Meiszl and subsequently perfected by Woolny. The Koettstorfer
method has also proved itself very useful. This method recommends
the determination of the capacity for saturation of the acids in the
fat investigated, by the number of milligrammes of potassium hydrate
required for saponifying 1 gram of fat. This saturation equivalent varies
for pure butter-fat, according to the experiments that have been performed
so far, between 221 and 233-4 milligi^ammes of potassium hydrate. The
other fats and oils show a lower saturation equivalent, generally from 197
to 178 milligrammes of potassium hydrate.

If butter has to be tested for the detection of foreign fats, a definite
opinion may be formed by determining, first, the sum of the insoluble
fatty acids by the Hehner method; secondly, the relative percentage of
volatile fatty acids by the Reichert-Meiszl-Woolny method ; thirdl}', the
refraction coefficient at 22° C. ; fourthly, the specific gravity of the fat
at the boiling temperature of water; and fifthly, perhaps also by the
Koettstorfer method. The number of c.c. of a tenth normal alkaline
solution required for 5 grams of butter-fat in carrying out the Reichert-
Meiszl-Woolny method varies, in most cases, between 21 and 33, and
the specific gravity of pure butter-fat lies between "8650 and '8685 at
100° C. The determination of the so-called iodine coefficient is, owing
to the great variation which it may exhibit, not well suited for the detec-
tion of foreign fats in butter. The complete analysis of butter can be
carried out as follows :^

(1) Determination of Water. — 5 to 10 grams of butter are weighed in
a small glass capsule, lightly covered, and are then allowed to melt on
the air-bath. The melted fat, after it has become clarified, is filtered in
the air-bath on to a weighed filter into a little weighed capsule, care being
observed in pouring it out that all the fat and nothing of the watery mass
lying beneath the fat is poured on to the filter. The Avatery residue in the
glass beaker is then dried at 100° C, and is left along Avith the fat in the
capsule and on the filter, Avhich should remain, if possible, standing in a
dry shelf, cooled in the desiccator, and weighed. This is repeated until
the AA-eight obtained by two subsequent Aveighings shoAvs at most a milli-

198 SCIENCE AND PRACTICE OF DAIRYING.

gramme of difference. From the loss of weight thus found — the weight of
the glass beaker is ascertained by weighing the butter, — the percentage of
water in the butter is calculated.

(2) Determination of the Fat. — The residue in the beaker is dissolved
and detached Avith a small glass stirrer as perfectly as possible from the
bottom of the beaker, washed out Avith pure ether, free from water, on to
a filter, which is fastened in a small funnel over the beaker containing the
chief quantity of the fat; the glass beaker and the stirrer are then washed
Avith ether, and the filter and its contents are washed with ether till
a few drops of the filtrant show no trace of fat when evaporated on a
watch-glass. The ether is then evaporated off, and the filter is dried in an
air-bath at 100°, cooled in the desiccator, again placed in the air-bath, and
after cooling weighed. This is repeated till the weight is constant.

(3) Determination of the Ash. — The residue remaining on the filter is
charred along with the filter-paper at a low heat, and after it has been
repeatedly boiled with distilled water and filtered it is burned to a white
heat. The filtrate is then added in small quantities to the ash in the
platinum capsule, placed in the water-bath to dry, and finally is burned
along with the filter, with a cover at a moderate heat, allowed to cool,
and Aveighed, the Aveight of the ash from the two filters being deducted.
Since fresh butter contains for the most part A'ery little over '1 per cent of
ash, the percentage of chlorine Avill only be about '003 per cent, and in
this AA'ay it is easy to arrive at a closely approximate estimation of the
percentage of salt in salt butter by a determination of the chlorine in
the ash.

(4) Determination of Proteids. — 80 to 100 grams of butter are weighed.
The fat, after being perfectly separated from Avater, is separated from
the remaining butter constituents, and is exactly determined in the
method described in (1) and (2), descriptive of the Avater and fat deter-
minations. The residue remaining on the filter-paper is then used for
the determination of the nitrogen. The proteids are obtained by multi-
plying the percentage of nitrogen found by the factor, 6 '3 9. As it is
doubtful, especially in the case of old butter and that made from sour
cream, Avhether all the nitrogenous substance belongs to the albuminoid
group, the number denoting the proteids may be regarded as a little
inexact.

(5) Determination of the Non-nitrogenous Soluble Organic Bodies {Milk-sugar,
Lactic Acid, &c.). — If the percentage of Avater, fat, ash, and proteids have
been determined exactly by tAvo duplicate analyses, showing close agree-
ment, the sum of the weight of these constituents is deducted from 100, the
difference being credited as milk-sugar, lactic acid, &c., or non-nitrogenous
soluble organic bodies. The attempt to determine this group of substances

THE INVESTIGATION AND TESTING OF BUTTER. 199

directly has been in my experience unsuccessful, as in washing the fat free
residue with water, sometimes more, sometimes less, of the nitrogenous
bodies is apt to be found in the solution. Naturally the uncertainty which
belongs to the number denoting the quantity of protein bodies will influ-
ence the number calculated by difference, which represents the quantity of
non-nitrogenous soluble organic bodies.

If butter has to be tested for its percentage of preservatives, with the
exception of salt, or for the determination of foreign solids which have
been added for the purpose of increasing its weight, the following process
may be adopted if it be not desired to detect the presence of foreign fats.

10 to 40 grams of the butter to be tested are melted in double or
three times the quantity of warm distilled water, a little alcohol is then
added, and the mass is stirred very slowly for about fifteen minutes at a
temperature just above the melting point of fat. It is then allowed to
stand still for some time, and the liquid lying below the fat, as well as the
residue, is submitted to chemical and microscopical investigation. Since it
is unnecessary to add to the special precautions to be taken in detecting
diflferent substances, and since adulteration of butter with potato meal,
gypsum, water, glass, &c., only occurs A'ery rarely, there is no necessity
to describe the methods for the detection of all possible and impossible
adulterants. If the butter be not adulterated, the liquid below the fat
becomes clear, or almost perfectly so, Avhen it is warmed with soda lye,
added in slight excess.

For the detection of the usual colouring agents, Hilger recommends the
following process: — About one-half of the liquid which has been filtered
from the sediment lying at the bottom under the fat, and which has been
obtained by the method above described, is evaporated down to a fourth
part of its volume, and is then divided into three like portions, a, b, and c-
Portion (a) is decomposed with hydrochloric acid. If this be followed by
a yellow coloration it indicates the presence of binitrocresol or binitro-
naphthol. Portion (h) is decomposed with ammonia for the detection of any
turmeric colouring matter. Portion (c) is finally heated with some sugar
and hydrochloric acid. The appearance of a red colour points to the pre-
sence of saffron. The remaining half of the original solution is evaporated
to dryness, and the residue treated with concentrated sulphuric acid. If
annatto be present a blue colour is produced. For the detection of colours
derived from carrots or marigolds no reliable tests are known. Genuine
saffron should not colour petroleum ether, as has been asserted.

The method for the determination of foreign fat in the butter has
been already described.

CHAPTER V.

CHEESE AND CHEESE-MAKING,

107. The Coagulation of Milk and the Properties of the Coagulum.

— The object of the manufacture of cheese is the utilization of the
caseous matter of milk. This is effected by coagulating the milk,
by precipitating the caseous matter in it by suitable reagents, and
by making the coagulated material, which represents the raw cheesy
matter, and which encloses all the remaining constituents of the
milk in varying quantities, into cheese, and by ripening fresh cheese
in order to render it suitable for consumption. From a very remote
period, it has been the custom to separate the solids of milk by
allowing it to sour spontaneously, or by treating it with rennet.
The coagulum obtained by spontaneous souring and that obtained
by the use of rennet were formerly regarded as identical. In the
years 1870 to 1875, through the labours of Schmidt and Kapeller,
and more especially through the accurate researches of Hammar-
sten, which have been already described in § 5, it was proved
that the coagulums respectively obtained by these two different
methods differed from one another. The chemical difference consists
in the fact that the coagulum obtained by souring contains nothing
but casein, whereas that obtained by rennet contains paracasein, a
decomposition product of casein. For that reason a distinction must
be made bet\veen sour-milk cheese and rennet cheese, and this all
the more because both kinds of coagulum have been proved to
manifest many other very important differences in their properties.
For the sake of simplicity we will call the acid precipitate curd, and
the rennet precipitate coagulum or raw cheese. As far as the
manufacture of cheese is concerned, the latter is more important and
valuable than the former.

The fresh coagulum obtained qX a temperature of 30° to 35° C. is
an elastic substance, scarcely soluble in water, and not in the slightest
degree sticky or greasy. When properly prepared, it contains a
large number of different kinds of spores, but no luxuriantly grow-
ing vegetative forms of bacteria or fission spores. It is admirably
suited for the manufacture of a large number of different kinds of

COAGULATION OF MILK. 201

cheese. It forms, to a certain extent, a rich medium for suitable
development, as desired, of the different kinds of micro-organisms
present. These organisms can be developed or suppressed, and the
growth of other kinds favoured. The most valued and the most
lasting kinds of cheeses are prepared from the coagulum.

The curd is not elastic, is less insoluble in water than the
coagulum, and is sticky and greasy. Since, in accordance with the
method by which it is obtained, it possesses a strong acid reaction,
and contains luxuriantl}^ growing lactic bacteria, it only forms a
suitable nutritive medium for a comparatively limited number of
bacteria and fission fungi, and offers, therefore, a much more
restricted basis for the manufacture of cheeses of different kinds.
In sour-milk cheeses, with few exceptions, the process of ripening
resembles in general the putrefactive process, and goes on from outside
to inside. In the case of the different rennet cheeses, on the other
hand, the process of ripening is essentially characterized as a process
of decomposition, or a process of fermentation, which goes on
throughout the whole mass with different phenomena, and appears
as a highly complicated process, in which, in addition to bacteria,
moulds, and perhaps also fission fungi, take part.

Coagulum and curd are distinguished from one another by the
fact that the former encloses the entire quantity of di- and tri-calcic
phosphates which are in suspension in the milk, while the latter
(the curd) only encloses a small quantity of calcic phosphate, since
a large portion of the suspended phosphate is dissolved by the lactic
acid which the separation of the curd gives rise to, and is, therefore,
not mechanically enclosed in the precipitate of the coagulation.

The process of milk coagulation by means of acids may be simply
explained as follows: — As has been pointed out in §5, the caseous matter
of the milk may be regarded as a chemical compound of casein or an
albuminoid (which plays the part of an acid), along Avith calcium oxide,
in the proportion of 100 parts of casein to 1"55 parts of calcium oxide.
From this compound of casein with lime, which is present in the milk as
a strongly coagulated colloidal mass, casein is separated, by the addition
of acids, in an insoluble from, i.e. in the form of a non-precipitable body.
This operation takes place in the souring of milk by acids.

The rennet souring of milk does not admit of such simple explanation.
We know, it is true, a good deal regarding the accompanying conditions
under Avhich it takes place, but Avith regard to the process itself little is
knoAvn. We knoAv little more Avith certainty than that it is a process of

202 SCIENCE AND PRACTICE OF DAIRYING.

fermentation, and that it is directly caused by ferments. Hammarsten has
carried out the most elaborate and trustworthy researches on this subject.
If we take a solution of caseous matter prepared according to his directions,
and precipitate or coagulate it with rennet, and then perfectly separate the
whey, obtained by steaming and the careful addition of acetic acid, from
the small quantity of rennet coagulum which is still present, and then
filter from the filtrate, we can separate out by means of alcohol, tannic acid,
or Millon's reagent, a protein body, which, in its chemical behaviour,
differs essentially from albumin and casein, and which is also free from
bodies of the nuclein type. Hammarsten names this body whey-protein,
and suggests with regard to the nature of rennet coagulation the following
theory: — The rennet ferment acts, within certain definite temperatures,
directly on the casein, and decomj)oses it, by means of hydration, into two
new albuminoids, in which the one, the whey-protein, remains in solution,
but the other, in the event of soluble lime salts being present, is precipi-
tated as a coagulum. Schulze, of Ziirich, suggests that the albuminoid
bodies which Hammarsten designates by the term cheese, a term which
admits of different meanings, should rather be designated by the term
paracasein. Soldner has shown that Hammarsten's statement, that the
rennet coagulation only takes place in the presence of dissolved calcium
phosphate, is so far incorrect, and it has been already shown that it does
not depend on the presence of soluble calcium phosphate, but chiefly on
the presence of soluble lime salts.

According to Hammarsten's own researches, or those carried out under
his supervision, casein, paracasein, aud Avhey-protein have been shown to
contain the following quantities of carbon, oxygen, and nitrogen: —

Carbon,

Oxygen,

Nitrogen, ...

As has already been mentioned, rennet coagulation has to be regarded
as a fermentation process. Fermentation processes are chemical processes
of a particular nature, in which organic bodies are decomposed into simpler
compounds by union with water. The characteristic of fermentation pro-
cesses consists in the fact that they can be induced by a particular fermen-
tation starter, an unorganized or organized ferment, and that for this purpose
a comparatively small quantity of ferment suffices; but the ferment does
not enter into a stable chemical combination either Avith the fermentable
body, or with the decomposition products formed. The progress of all
processes of fermentation is influenced to a large extent by the ferment, by
the percentage of water in the fermenting mass, and by the temperature

Casein.

Paracasein.

Whey-protein

52-96

52-88

50-33

7-05

7-00

15-65

15-84

13-25

RENNET AND ITS PROPERTIES. 203

The action of unorganized, or chemical or soluble (hydrolytic) ferments, is
believed to take place in such a way that a molecule of the ferment unites
with a molecule of the transformed body, and forms a compound which is
immediately decomposed by water again. The molecule of the ferment
separates out unchanged, and bodies are formed which owe their origin to
the hydration of the body undergoing fermentation. It may be supposed
that the budding fungi and bacteria act indirectly in exactly the same
manner, if it be assumed that they possess the capacity to separate out
under certain conditions unorganized ferments or enzymes.

108. Rennet and its Properties. — By the term "rennet" in dairy-
ing, is understood the liquid or powdered preparations, suited for
purposes of cheese manufacture, which contain as their chief
constituent that characteristic rennet ferment which exerts an
extraordinarily powerful action on the caseous matter of the milk.
This ferment is found in the stomach of a large number of animals,
and also in the human stomach. It is especially abundant in the
stomach of young mammals while they are still suckling; and is a
secretion of the rennet-glands, which are embedded in the lining of
the stomach. For the preparation of rennet, calves' stomachs are
almost exclusively used, on account of the ease with which they are
procured. Up till now it has not been possible to obtain the rennet
ferment in a pure condition. From an extract, obtained by treat-
ing the dry stomach of a calf with a 5-per-cent salt solution, and
then by increasing the percentage of salt to 10 per cent, Soldner
obtained a precipitate which, when dried, formed a gray-brown
powder. One part of this powder was sufficient to coagulate at
35° C, in 40 minutes, one million parts of milk. As the powder
contained 36 per cent of organic matter, one part of this was
sufficient, therefore, under the above, conditions, to effect the
coagulation of 2 8 million parts of milk. Further, as the organic
substance did not consist of pure rennet, the ferment must there-
fore exert a much stronger action on milk. The rennet ferment
belongs to the unorganized class of ferments, and more parti-
cularly to those which are able to decompose albuminoids. Its
action is connected with well-defined conditions, which can be
accuratel}^ and shortly described. Its action does not take place at
all if the milk lack soluble lime salts, and if the milk possess an
alkaline reaction, however faint. Milk which colours, or which
reddens phenol-pthalein perceptibly, is not coagulated b}^ rennet.
An acid reaction, within certain narrow limits, assists the action of

204 SCIENCE AND PRACTICE OF DAIRYING.

rennet. When, however, free acid develops in the milk, which is
able to attack the caseous matter, the coagulation which is formed
no longer exhibits those properties which belong to a coagulation
exclusively formed by rennet. It is worthy of note that the
reaction of milk is not altered to the slightest extent by the action
of rennet. The action of the rennet ferment is largely influenced
by the temperature and by heat.

By boiling, or by the addition of an alkali, milk loses the power, either
entirely or partially, of being precipitated by rennet. In milk which has
been heated for a long time, or in milk which has been boiled, after the
addition of rennet, a precipitate is formed, it is true, but it consists of a
coagulum Avhich is highly flocculent, and never forms a firm united mass.
The reason of this, as Soldner has shown, is due chiefly to the fact that
in this action a precipitation of calcium phosphate is effected, which causes
the entire removal or diminution of the soluble lime salts. Probably
other changes unfavourable to the action of rennet may also take place
in the milk. Milk which has been boiled, or to which an alkali has
been added, and which has thus lost, either entirely or partially, its
susceptibility to the action of rennet, regains this susceptibility if it be
treated with calcium chloride or other soluble lime salt, or if a small
portion of the precipitated lime salts be dissolved again by the addition
of carbonic acid or dilute acid. If fresh milk be not coagulated by the
action of rennet — a fact which has been very rarely noticed, — this may
be accounted for by some disturbance in the milk-gland, through which
the milk exhibits a slightly alkaline reaction, and does not contain soluble
lime salts.

Fresh milk of ordinary quality exhibits to litmus colouring matter an
amphoteric — that is, a faintly alkaline, and, at the same time, a faintly acid
reaction. The degree of acidity caused by the presence of acid phosphates,
Avhich varies within narrow limits, may be easily determined by titration.
This is carried out, according to the directions of Soxhlet and Henkel,
as follows: — 50 c.c. of milk is titrated after the addition of 2 c.c. of a
2-per-cent phenol-pthalein solution and ^ normal soda solution. The end
of the reaction is denoted by the formation of a faint red colour in
the fluid. The number of c.c. used, when calculated on 100 c.c. of milk,
represents the measure of the acidity of the milk. This, as a rule, amounts
to 7. The greater the acidity of the milk, the more powerful is the action
of rennet when the conditions are otherwise similar. By the addition of
-|- normal soda solution, or^ ^ normal hydrochloric acid solution, we can
impart to the milk at any time a quite definite acidity. In using the
numbers denoting the acidity of milk found by Soxhlet and Henkel, it

RENNET AND ITS PROPERTIES.

205

must be assumed that we are dealing with milk which has not been
diluted with water. By the addition of water to milk its acidity is
diminished, owing to the fact that the calciimi phosphate, with alkaline
reaction, is carried into solution.

The strength of the action of the rennet increases with increasing
temperatures, at first slowly, then always more quickly, and reaches its
maximum at 41° C, and rapidly decreases from that point with increase
of temperature. It has further been established that the rennet coagulum
at 15° C. is flocculent and spongy, at 25° to 45° C. it is more or less firm,
resembling porcelain, and at 50° C. it is again loose and spongy and jelly-
like. Solutions of rennet become permanently inactive if heated to a
temperature of over 60° C. If they be kept for some time at a compara-
tively high temperature, but below 60° C, they lose their strength. A
solution of rennet which acted upon milk (fresh) in the proportion of 1 to
3750, and which, to effect sterilization, was heated for 32 hours at 59° to
60° C, and which during that time was maintained at a neutral reaction,
lost in the above treatment 44 per cent of its original strength. According
to experiments carried out in my laboratory by Dr. F. Baumann, solutions
of rennet of neutral reaction cannot be sterilized at temperatures over
60° C, without at the same time becoming inactive. With regard to
the relations of temperature to rennet action between 20° and 50° C, the
following numbers may be quoted. The table gives the quantities of
milk coagulated at different temperatures between 20° and 50° C. by equal
amounts of rennet, taken from the same preparation of rennet ferment,
in equal periods of time. Taking the quantity of milk coagulated at 41° C.
as 100, the following are the results:

20° .

. 18

25 .

. . 44

30 .

. 71

31 .

. 74

32 .

. 77

33 .

. 80

34 .

. 83

35 .

. 86

jsults :

— ■

36° .

.. 89

37 .

.. 92

38 .

.. 94

39 .

.. 96

40 .

.. 98

41 .

.. 100

42 .

.. 98

43 .

.. 96

44° .

. 93

45 .

. 89

46 .

. 84

47 .

. 78

48 .

. 70

49 .

. 60

50 .

. 50

The limits of temperatures between Avhich, in actual practice in cheese-
making, milk is coagulated with rennet, are 20° and 48° C. As a rule, the
most commonly applied temperature is between 30° and 35° C

Watered milk coagulates more slowly than pure milk, and by the
addition of a large quantity of water, milk can be deprived of the power
to form a firm coagulum on the addition of rennet. If solutions of rennet
be submitted for some time to the action of light, they gradually decrease

206 SCIENCE AND PRACTICE OF DAIRYING.

in strength. The following facts and directions may be stated with regard
to the action of rennet : —

(1) The time of coagulation under like conditions of temperature, and
strength and amount of rennet used, is directly proportional to the quan-
tity of milk to be coagulated.

(2) The time of coagulation is, under similar conditions of temperature
and equal quantities of milk, inversely proportional to the strength or the
quantity of rennet used.

(3) The strength of rennet is, under like conditions of temperature
and time of coagulation, directly proportional to the quantity of milk
acted upon.

On the basis of the last of these dicta, the custom of determining the
strength of the diflferent kinds of rennet has been founded. These condi-
tions can only be regarded as holding true at temperatures between 30°
and 40° C, and in such cases where the quantity of rennet used for
coagulation is not more than will effect coagulation in from five to ten
miniites. If the quantity of rennet be increased, and the quantity of milk
remain the same, the time of coagulation does not increase in the same
proportion as in (2) but more quickly with the increase in the quantity
of rennet.

Formerly only solutions of rennet were used in practice. These
solutions were either made in the cheese factory daily for immediate
use, or were kept in very small stocks. At present, in Germany,
solutions of rennet are manufactured on a large scale for sale, and
these are almost exclusively used. Rennet is also sold in the form
of a powder. The introduction of this practice dates from about
1870, when it was introduced by the apothecary Krick of Bar-le-
Duc, in France, and by Dr. Christian Hansen in Copenhagen, and
soon also by others.

At first the solutions were only in limited demand. They were
very dear, and were far from satisfactory. It was only after
Soxhlet had given definite instructions, based on extensive investi-
gations, with regard to the most economical and useful application
of strong rennet solutions, that commercial rennet was improved in
quality and reduced in price, and gradually in the course of time
found its way into more general use.

The strength of the rennet preparation is best measured by
estimating how many cubic centimetres of a milk of ascertained
acidity, for example of an acidity of 7, are coagulated by one cubic
centimetre of rennet solution or 1 gram of rennet powder at a

RENNET AND ITS PROPERTIES. 207

temperature of 35° C, in 40 minutes. This is best carried out
as follows: — 5 c.c. of the rennet solution which it is desired to
test, or a watery solution in which 5 grams of the rennet powder
is dissolved, are made up to 100 c.c. with distilled water. After
thorough mixing, 10 c.c. — representing 'o c.c. or "5 of a gram of
the rennet preparation — is drawn off with a pipette and added to
500 c.c. of milk possessing an acidity of 7, which is then heated to
exactly 35° C. The exact time to a second is noted when this takes
place. The solution of rennet is blown with considerable force from
the pipette into the milk, in order that it may be uniformly distri-
buted throughout the mass, which is quickly submitted to a rotatory
motion. As is obvious, there will be one part of rennet for every
1000 parts of milk, that is, 1 c.c. or 1 gram of rennet per 1000 c.c.
of milk. The thermometer, which has been already placed in the
milk, is then gently moved to and fro, and the time noted which
elapses till coagulation becomes apparent, that is, till fine particles
of coagulated milk are apparent behind the thermometer as it is
moved as carefully as possible. The temperature of the milk must
be maintained during the whole operation as nearly as possible at
35° C. If, for example, the coagulation period has been observed to
last 5'55 minutes, then the quantity of milk (x) which would be
coagulated at the same temperature by a similar quantity of rennet
in 40 minutes' time is as follows: —

5-5 : 40 :: 1000 :a; = 7207.

The rennet preparation is thus found to possess a strength of
1 : 7207, or, roughly speaking, 1 : 7200.

The commercial solutions contain, in addition to rennet ferment,
small quantities of pepsin, a non-organized ferment which produces
lactic acid, comparatively large quantities of slimy matters, and other
organic substances, the composition of which is little known. They
contain salt or alcohol, and often also other preservatives, such as
boracic acid, glj^cerin, ethereal oils, thymol, salicylic acid, benzoic
acid, &c. All these .substances increase the keeping property of
the rennet solutions at the expense of their strength, since they
render a portion of the rennet ferment inactive.

Rennet powders, on account of the method of their preparation,
are richer in the ferment and poorer in pure organic substances
than the pure commercial solutions of rennet. They are obtained,
as a rule, by separating and drying the precipitate prepared by

208 SCIENCE AND PRACTICE OF DAIRYING.

suitable methods from the rennet solutions, and are rich in rennet
ferments.

A commercial solution of rennet should possess an inviting
appearance, should be clear, and should neither possess a disagree-
able nor a strongly aromatic smell. They must possess keeping
properties, and should not lose in the course of a year more than 25
per cent of their strength. They should not be too weak, and if
kept for several months protected from the light, they should possess
a strength of 1 to 6000; and, finally, they ought not to be too dear.
A litre of a good rennet solution, possessing a strength of from 1 to
10,000 to 1 to 6000, should not cost more than two to three marks.

A good commercial rennet powder should have an appearance
almost entirely white, should possess practically no smell, and on
being dissolved in water should leave only a very small residue.
It should obviously not contain lead, a body which has been found
in considerable quantities in some samples. As rennet powder is
richer in the amount of ferment it contains, and poorer in foreig-n
constituents than the commercial rennet solutions, it possesses an
advantage over the solution. Up till now, however, the use of the
powder in practice has been less popular than the use of the more
convenient commercial rennet solutions, since there are different
and not altogether unimportant inconveniences attached to its use.
Rennet powder must be carefully protected, for example, from damp,
since if it become moist it decomposes and putrefies. Further,
before its use it must be perfectly dissolved for fifteen minutes in
water or sweet whey. If the milk be treated with the solution
before the powder is perfectly dissolved the curd will not be uni-
form. There are rennet powders in commerce which possess a
strength of 1 to 300,000 or even greater. In addition to rennet
powders, rennet preservers are also sold in the form of tablets.

The juices of certain plants, for example, the fig-tree (Ficus
CaHca), artichoke (Cynara scolimus), some kinds of thistle (for
example, the Carlina corymbosa and C. acaulis), the melon-tree
(Carica Papaya), withanie (Punceria coagidans), the butter- wort
(Pinguicida vulgaris and P. alpina), exert on milk a similar action
to that of rennet. The juices of the fig-tree and of some thistles
are the only ones of these which in rare cases have been tried in
practice. The special rennet used by the Israelites was not prepared
from plants, but from the stomachs of calves killed according to the
Jewish law.

RENNET AND ITS PROPERTIES. 209

As mentioned, the rennet required was formerly prepared in the
cheese factory itself. In such cases it was made from dried calves'
stomachs, Avhich had been allowed to stand for some hours, partly in pure
water and partly in water which had been rendered sour with acid whey,
citric acid, or wine vinegar, at a temperature of from 20° to 35° C. Occa-
sionally, in order to preserve them, there was added to such preparations,
if they were made on a large scale, salt, spirits of wine, pepper, salt-
petre, aromatic herbs, nutmeg blossom, cinnamon blossom, laurel leaves,
ethereal oils, and such like. Under certain circumstances, calves' stomachs,
which were specially preserved and kept in the form of balls, or packed
in stone jars, were utilized for the preparation of the necessary rennet
solutions. These Avere obtained as follows: — The calves' stomachs dried
in the air were first of all thoroughly separated from the fat, then
finely minced, and treated with 5 per cent of salt and pepper. The mass
was then dipped in vinegar, made into a ball, and after lying for eight
to twelve hours, was mixed with a quantity of butter-milk sufficient to
make it into a paste, and to admit of its being conveniently made into
balls as large as the fist. These balls were left for from three to four
weeks in a moderately warm, dry place, slightly smoked, and then kept
for use.

Soxhlet's prescription for the preparation of good keeping rennet solu-
tions is as follows : —

The fresh stomach is emptied, blown up quickly, dried in the air, and
kept for at least three months. After the portion devoid of folds has been
removed, it is cut into pieces about a square centimetre in size; for every
100 grams of stomach 1 litre of water, 50 grams of salt, and 40 grams of
boracic acid are taken. It is then left to stand at the ordinary temperature
of the room for five days, with frequent shaking. To every litre of water
used, 50 grams of salt are added, and the solution is then filtered. For 1
litre of water there should be obtained 800 c.c. of filtrate, which should be
made up to a litre by the addition of 200 c.c. of a 10-per-cent salt solution
saturated Avith boracic acid. Such rennet possesses a strength of about
1 to 10,000, and that after lying for two months. Per litre it costs as
follows : —

From 3 to 3-5 calves' stomachs at 20 pfennig, 60 to 70 pfennig.

50 grams of boracic acid at 2 marks per kilo., 10 „

Salt and filter-paper, 5 ,,

Total, 75 to 85 pfennig.

Instead of boracic acid, alcohol may be used, but the rennet solution
obtained possesses poor keeping properties. 100 grams of calves' stomach

(M175) o

Blumenthal's
Rennet Powder.

0-87

Blumenthal's
Extract.

85-49

Hansen.

78-86

1-06

0-19

2-00

2-06

0-84

0-24

96-01

13-48

18-90

100-00

210 SCIENCE AND PRACTICE OF DAIRYING.

are treated with 1 litre of water and 50 grams of salt. After five days
50 grams of salt are dissolved in the liquid, and from 100 to 110 c.c. of
90-per-cent alcohol are added. The liquid is then filtered. The filtrate
thus obtained contains per litre 100 grams of the calves' stomach, 10 per
cent of salt, and 8 to 9 per cent by volume of alcohol. Fresh rennet solu-
tions prepared in this way lose about 30 per cent of their strength during
the first two months, but from that time remain for the next eight months
and longer almost quite constant in their strength. On this account,
rennet solutions should only be introduced to the markets, and sold, after
they are two months old.

According to Dr. Schmoger, samples of rennet powder of the following
brands gave the following results : —

"Water, ...

Nitrogenous organic matter, ...

Non-nitrogenous organic matter.

Ash,

The ash of each of these three kinds of rennet consisted essentially of salt,
and exhibited only a Aveak boracic-acid reaction.

109. The Application of Rennet in Practice. — The rennet serves
to coagulate milk in a very short period of time, and to obtain from
it the coagulum which forms the raw material in the preparation of
cheese. A too quick coagulation of milk does not favour the further
treatment of the coagulum for conversion into cheese. The period
of coagulation in the preparation of most kinds of cheese varies
from 15 and 90 to 120 minutes. In the preparation of the majority
of cheeses, however, it does not last for more than 40 minutes.
Observations show that the coagulum is not immediately formed
after the addition of rennet, the physical condition of the milk being
changed quite slowly. It first of all gradually becomes viscous or
sj^rupy, then gelatinous, and finally so firm that when the finger
is dipped into it and then slowly drawn out again, the coagulated
matter gradually breaks. The action of the rennet, however, does
not cease wdth the lapse of the coagulation period. The coagulum
becomes firmer, and poorer in water, until, in a longer or shorter
period, it reaches as great a degree of firmness as it can possibly
attain under existing circumstances. During the subsequent
thickening, a green yellow-coloured whey is formed, which increases

THE APPLICATION OF RENNET IN PRACTICE. 211

the firmer the coagulum becomes. The firmness of the coagulum
depends, in the first instance, on the strength of the rennet used,
on the length of the coagulation period, and on the temperature
during coagulation. The percentage of water in the coagulum is in
inverse proportion to its firmness. Experience has shown that
the coagulum, of each of the many different kinds of rennet cheeses,
requires a certain definite percentage of water, and a certain definite
firmness. Since these two things are unalterably determined by the
nature and method in which the separation of the milk is effected,
and since that depends on slight delicate differences, the coagulation
of milk by means of rennet demands the greatest attention and
care. This is all the more the case, as the firmness and the per-
centage of water of the coagulum is not merely dependent on the
period of coagulation, and the temperature and the quantity of
rennet used, but is also dependent on the percentage of the fat, and
the acidity of the milk. In the manufacture of very soft cheeses,
the milk is separated at a temperature of from 20" to 28° C, and the
period of coagulation is at the same time lengthened. On the other
hand, if hard-keeping cheeses, suitable for keeping for a long time,
are to be prepared, the coagulation is effected at from 28° to 35° C,
and its duration is shortened. If coagulation take place very
slowly, that is to say, if it occupy about an hour or more, certain
dangers arise which have to be watched, and subsequently, if pos-
sible, have to be guarded against. The longer the coagulation period
the more difficult it is to keep the milk during the whole time at
an equable temperature. In the case of the manufacture of cheese
from whole -milk, this difficulty manifests itself in the collection
of the fat in the surface layers of the coagulum. Too short a
coagulation period can also give rise to undesirable results. The
coagulum, when formed too quickly, may become so firm that it is
impossible to work it in mass, and to break it up as finely as is
necessary. In the manufacture of the same kind of cheese, it is
necessary, in winter, to raise the coagulation temperature a little
above that maintained on an average. This is also necessary in the
case of milk which contains more than the average percentage of
fat, or which is relatively less acid.

The object of all operations in the separation of milk is to obtain
a coagulum which is of a perfectly uniform nature. This has to be
kept in view in practice before everything else in coagulating with
rennet.

212 SCIENCE AND PRACTICE OF DAIRYING.

In the separation of milk, in addition to the necessary quantity of
good rennet, and a good cheese -vat and suitable measuring vessels, a
thermometer and a ladle for mixing the rennet with the milk will also he
required. The following is the method: — After the milk has been brought
by suitable heating and stirring to exactly the required temperature, the
necessary amount of rennet is mixed into the milk. If it be intended to
colour the coagulum of the cheese, the colouring matter ought also to be
added in the exact proportion required, and should be thoroughly mixed
with the milk. The milk is then allowed to rest in the cheese-vat covered
with a lid, should it be necessary to maintain an equable temperature, and
the liquid left to stand. The solution of rennet (rennet in the form of
a powder must be dissolved before application) should form at least 1 per
cent of the volume of the milk. The milk is tested from time to time, at
first after considerable intervals, and subsequently oftener, in order to see
if coagulation have taken place. Before proceeding further, the coagulum
must be allowed to attain the desired degree of firmness. As soon as
this is reached, it is ready for further treatment, in the cheese-vat, for the
manufacture of cheese.

For taking the temperature during the process of coagulation, a ther-
mometer fitted with a bi'ass scale attached to a strong board, polished on
all sides, is used. The necessary rennet is kept (when a rennet solution is
used) protected from the action of light, and if a rennet powder be used it
should be kept in a perfectly dry place.

If it be desired to test the rennet solution which is used, it can be done
in the following manner : — The entire quantity of the milk is brought into
the cheese vessel at the proper temperature. An empty dish, which will
hold at least two litres, is placed in the milk at the beginning of the
warming process, in such a way that it floats and assumes the temperature
of the milk. In the meantime 10 c.c. of the rennet solution are measured
out and diluted with water to 100 c.c. As soon as the mass in the vessel
has reached the desired temperature, a litre of milk is poured into the
dish, 10 c.c. of the diluted rennet solution is added and mixed, and the
time which it takes to start coagulation is noted exactly to a second. If,
for example, it has been observed that the milk in the bowl coagulates in
8-5 minutes, and if it be desired that the coagulation of the whole amount
should last for about 40 minutes, all that is necessary is to divide 8-5 by
40 in order to find how many c.c. of rennet will be required for every litre
of milk. Since 8-5 divided by 40 is -2125, for every litre -21 c.c. will be
required approximately, or for every 100 litres 21 c.c; and since a litre
weighs approximately 2 lbs., for every 100 lbs., 10-5 c.c. of rennet will
be required. It is possible at the same time to ascertain whether the
coagulum possesses the proper condition, by making an exact test of the

THE COLOURING OF CHEESE. 213

coagulated mass in the bowl. Directly after the end of this operation,
Avhich can be done in less than 10 minutes, and if the temperature of the
milk have not changed, the dish may be removed, and coagulation by the
addition of rennet may be proceeded Avith. For example, if there be

657 lbs. of milk in the dish, ' — = 68-985, or approximately 69 c.c.

of rennet may be used, to which the necessary colour has been added. If
the coagulation be not exactly concluded within the prescribed time, on
account of the test in the dish not having been accurately carried out,
the quantity of rennet used can be altered the next day so as to rectify
the inaccuracy.

110. The Colouring of Cheese. — Nearly all the better kinds of
rennet cheese, especially tlie finer kinds intended for export, are
coloured when they are in the state of curd, and some Dutch,
English, and American kinds are also externally coloured. Gener-
ally the curd is coloured of a very weak yellow or reddish-yellow
tone, rarely is it coloured of a deep orange-yellow. The cheeses
prepared in Switzerland and S. Germany are of a faint golden-
yellow colour. The Dutch, English, and American cheeses are more
or less of a reddish-yellow coloui\ For colouring cheese when in a
state of curd, only liquid cheese-colourmg substances are used, such
as solutions of annatto colouring matter in an alcoholic soda solution,
or alcoholic solutions of saffron. These are added to the milk at
the same time as the rennet. The saffron solution imparts to the
curd a gold-yellow colour, and the annatto solution a red-yellow
colour.

Formerly milk Avas treated according to taste, for the purpose of
colouring the curd, with commercial annatto paste or saffron powder. At
present, in all cheese factories Avhere Avork is carefully carried out, only
commercial liquid cheese colours are used, a definite proportion of
which is added to the milk. The preparation of good colouring solutions
of annatto is so inconvenient that they should not be readily used in
cheese-making. On the other hand, solutions of saffron are very simply
obtained in the folloAving Avay. For every gram of saffron, 20 c.c. of a
mixture composed of equal parts of distilled AA'ater and common spirits of
wine are added, and the saffron is dissolved in this mixture in a roomy
bottle, corked, and alloAved to stand for from four to five days at the
ordinary temperature of the room, being frequently shaken and finally
filtered through linen. If a pound of saffron cost 50 marks, and if for
every pound of milk 2 c.c. of this extract be used, the cAvt. of cheese Avill

214

SCIENCE AND PRACTICE OF DAIRYING.

cost about 24 pfennig to colour. The colouring of cheese in the curd is,
therefore, by this method, cheaply effected, even if commercial colouring
solutions are used, which are more expensive than the home-made ones.

111. Utensils Necessary in the Preparation of Cheese. — In the
preparation of curd, special easily heated cheese vessels are used,

Fig. 57.— Cheese Vat for Steam.

which in different districts are differently shaped and made out of
different kinds of material, and these are heated either over an open
fire, or with steam or hot water. With regard to the crude and
wasteful method in which milk is warmed in the cheese vessels by
the simple introduction of steam (fig. 57), this has been entirely
abandoned, even in the districts in which it was formerly practised.

Fig. 58.— Cheese Vat for Hot Water.

The cheese vessels are generally round and boiler-shaped, or rec-
tangular vat-shaped. On the continent of Europe, round vessels
or cheese-tubs are almost entirely used, and in the large American
and English cheese factories, in which the manufacture of cheese is
conducted on a large scale, oblong cheese-vats are almost entirely
used (fig. 58).

UTENSILS NECESSARY IN THE PREPARATION OF CHEESE.

215

The cheese-tub (fig. 59) is best made out of the best bare copper,
that is to say, copper not tinned. It should not be lai'ger, or even as
large, as to allow 1500 litres (328 gallons) of milk to be converted
into cheese at once. Even in a vessel of this size it is difficult to

:Mete

0123456789 10
Fig. 50.— Fixed Cheese Kettle with Movable Firing (Perpendicular Section).

obtain a curd perfectly uniform. Vats of a hemispherical shape are
to be preferred to those of more strongly bulging or of conical shape,
or that narrow towards the top. The cheese- vat is heated either over
an open fire or with steam. In Switzerland, Upper Italy, Austria, and
in S. Germany, heating over an open fire is still generally practised.
The kettle is either hung
on a movable bar over a
closed, often even an open
fireplace, or the kettle is
built-in, and the fireplace
is brought on a small iron
rolling waggon which
runs on a rail in a groove.
The latter is better than
the former. As, however,
it is not possible, in heat-
ing a kettle over an open

fire, to regulate the temperature of the milk and the curd as exactly
and as reliably as it is in the case of a slow and regular steam-heating
arrangement (fig. 60), this latter method is distinctly preferable. The
unseemly Danish cheese jackets used for steam heating are certainly
very impracticable. The copper kettles, the under part of which is

li;; GO —Fixed Cheese Kettle «ith Mo\ablL Filing

216

SCIENCE AND PRACTICE OF DAIRYING,

double walled, and in which the steam is introduced into the hollow
space between the walls, have also proved themselves unsuitable. The
following method, which is characterized at once by its simplicity
and cheapness, meets all requirements. A copper circular-shaped
kettle with a projecting edge is placed in a common wooden vat.
Steam is conducted through a tube which opens just above the bottom
of the kettle. Opposite, a tube bent at its outward end and open at
both ends is placed closely above the flooring of the vat, to permit the

Decioio

2Meter

Fis- 01.— Steam Cheese Kettle (Perpendicular Section).

exit of the condensed water. In front of the inside end of this tube
a clamp is fixed, which does not entirely lie on the floor of the vat,
and by this means the exit of the steam is regulated. Where no steam
kettle is available for the purpose, the steam may be prepared most
easily in an ordinary built-up kettle, the lid of which is screwed on
and provided with a wide opening. This opening is closed with a
round iron plate, the weight of which gives to the steam the neces-
sary slight pressure, and at the same time acts as a safety-valve.
The steam conduction-tube passes through the lid, which is provided
with a cock and a second tube open at both ends, and reaches almost
to the foot of the kettle. This simple arrangement suffices if the
contents of the cheese kettle are only to be heated to about 40° C.
If, however, the temperature is to be raised to 60° C. or above, the
operation is more quickly effected by working with steam under

UTENSILS NECESSARY IN THE PREPARATION OF CHEESE.

217

greater pressure. In this case it is recommended to substitute a
wooden vat with a metal casing which is provided with a bad heat
conductor — a covering of wood, or a wooden jacket (fig. 61).

The necessary size of the water kettle for supplying steam is easily
ascertained, if it be remembered that water converted into steam at 100" C,
and under an atmospheric pressure of 760 mms., takes up approximately
537 heat units, and that saturated steam Avhen it is condensed into water
gives off the same quantity of heat. For example, if 1500 kilos. (328
gallons) of milk is the largest quantity which it is desired to heat at one
time from 10° to 35° C, that is, to increase the temperature about 25°,
37,500 heat units will be required, taking the specific heat of milk to be
equal to that of water. Every kilo, of steam yields, when perfectly con-
densed, at 100° C. 537 units, and when water is cooled to 35° C. 65 more
uuits, altogether 602 units of heat. As 602 goes into 37,500 exactly
62 "29 times, there must be used in the vat, if no loss is to take place,
about 63 kilos, of water, that is, 63 kilos, of water must be converted into
steam. With regard to the unavoidable losses, especially with reference
to the fact that it is very convenient to utihze the hot water in the kettle
as may be desired for any purpose, the size of the kettle should be double
what is necessary, at least, that is to say, of such a size that it vill contain
126 kilos, or more.

A good arrangement for the heating of a cheese-kettle with steam has
many other advantages as contrasted with the heating over an open fire.
Apart from the fact that it renders all operations which have to be carried
out in the kettle distinctly easier, it is simpler, more cleanly, distinctly
cheaper, since in addition to wood, turf, and peat, coal, brown -coal, or
coke may be used, and it allows larger quantities of hot water to be
prepared every time, and at the same time may be used for heating the
dairy rooms Avith steam or hot water.

The large American cheese-vats are
made out of tinned copper, white-metal, or
tin, and are heated usually with hot water,
occasionally, however, with steam. The
most largely used in America is the Oneida
cheese- vat (fig. 62). The other vats which
are in common use are Armstrong's, Mil-
ler's, Jones's, Falkner Stuart's, Seeger's,
and others (fig. 63). During the second half of the seventies, the
experiment was made of introducing the American cheese- vats into
Germany, which was assuredly not in the interests of German

Fig. 02.— Oneida Cheese Vat (Per-
pendicular Section).

218

SCIENCE AND PRACTICE OF DAIRYING.

cheese-making. The attempt did not, however, meet with con-
spicuous success. Even had it succeeded, it is scarcely Ukely that
there could be obtained in these vats a curd of a similar composition
throughout its entire mass; and it is absolutely impossible to treat
the curd in them subsequently in such a manner as to keep it of a
uniform nature. The American cheese-vats are admirably adapted
for dairies in which the object is to obtain cheese by means of daily
work carried out on a large scale of manufacture, and where the

Fig. 63.— Cheese Tub.

largest possible quantities of milk are handled, rather than for the
preparation of a cheese of the best possible average quality.

112. The Treatment of Curd before it is Moulded. — In the pre-
paration of certain kinds of soft cheeses, the curd, after being
coagulated, is only allowed to remain a short time in the cheese-
vat to become thick, and is then immediately pressed into its shape
by means of flat scoojjs, without having been previously cut into
small pieces. In the preparation of most kinds of cheese, however,
the curd is cut gradually into pieces, of such a size as is desirable
for the properties of the cheese to be manufactured. It is advis-
able that all the pieces should be of a uniform size. In the curd
which is cut into pieces for the different kinds of cheeses, the pieces
vary, for example, from the size of an apple or a cherry-stone to
that of peas or hemp-seed, &c. In the cheese-kettles, the curd can
be cut easily, by means of a scoop, cheese-knives, or stirrers (flgs.
64-65), into any size of piece that is required. This cannot be
done in cheese-vats, where it is not possible to stir the curd. With

THE TREATMENT OF CURD BEFORE IT IS MOULDED.

219

the American curd-knives (figs. 66-68), which consist of a row of
brass knives placed parallel to one another, either horizontally or
vertically, it is possible to cut the curd into large-shaped pieces of

Fig. 64. — Cheese Ladles.

Fig. 65.— Curd Stirrer.

Fig. 67.— Curd Knife.

a certain size, but it is not easy to further reduce the pieces to a
uniform smaller size in the vats themselves. To effect this purpose,
a special implement is used in the American cheese factories, viz.
the curd-mill, by means of which the curd, after being
separated from the whey, is reduced into smaller pieces.
The cheese-vat and curd-mill must be used together,
for where one of these utensils is used the other cannot
be dispensed with. It would be altogether useless,
on the other hand, to grind
the curd in a curd-mill
where a kettle had been
used for cheese making.
For stirring the broken
curd in cheese-vats, a spe-
cial curd-stirrer is used
(fig. 69).
While the curd is being cut in the cheese vessels it becomes
firmer, and poorer in water: in fact the smaller it is cut the less
water does it contain. In the preparation of both kinds of hard
cheese, the subsequent hardening is effected by means of another

Fig. 63. -Curd
Knife with Hori-
zontal Blades.

Fig. 69.— Curd Stirrer.

220 SCIENCE AND PRACTICE OF DAIRYING.

heating. This is done by raising the temperature of the contents
of the cheese vessels gradually, occasionally only a few degrees
above the coagulation temperature, but occasionally also to a higher
temperature, and in a few cases up to 75° C. In the preparation
of Cheddar in most American cheese factories, the curd is sub-
mitted to a peculiar treatment. The cut curd is left, either under
the whey, or after the whey has been removed, in a covered cheese
vessel, at a temperature not far removed from the coagulation
temperature, to lie until it has gained the proper degree of ripeness,
that is, until it possesses a certain sticky property and a sour
smell. The degree of ripeness is judged by testing with hot irons,
after the method introduced by L. M. Norton. This test is carried
out in the following way: — An iron bar is made red-hot, and then
allowed to cool till it no longer shows redness in daylight. It is
then brought into contact with a small piece of the curd, and the
behaviour of this piece of curd is observed. If the curd cling to
the iron, and is drawn out, when the iron is moved away, in threads
which possess a length of from 1 to 2 centimetres, the proper degree
of rij5eness has been reached. Evidence that the ripening has not
been carried on far enough is afforded by the curd not sticking to
the iron at all, or if the ripening has been carried too far, the curd
sticks in such a manner that long threads can be drawn.

All processes which have to do with the contents of the cheese-
vat after the coagulation of the milk, and up to the process of
shaping the cheese, and all precautions which are taken in these
operations, should have as their object to maintain the curd of a
uniform composition.

When the cheese is made in kettles, this last requirement can only be
properly carried out if the process he thoroughly understood. As soon
as coagulation has taken place, and the curd has become sufficiently firm,
the lid is removed from the kettle in order to commence cutting, flat
pieces of curd being scooped from the middle, Avhere cooling goes on most
slowly, Avith a cheese-scoop, and laid round the edge of the kettle for the
purpose of keeping the curd in that part Avarmer. Thereupon, after the
curd has become sufficiently firm, it is cut A\ath AA'ooden cheese-kniA^es in a
vertical direction, and then crossAvise throughout the AA^hole mass. The
curd is then slowly and continuously turned horizontally Avith the cheese-
ladle round the A'at, and at the same time is being reduced to smaller
pieces. The cutting is effected by the sharp front-edge of the cheese-
scoop. "When the curd has been reduced to a sufficiently small and firm

THE SHAPING OF RENNET CHEESE. 221

condition by this operation, during which a scoop is held in each hand, it
is then worked with, the stirrer until the pieces are of the desired size,
and possess, at the same time, the proper elasticity, firmness, and dryness.
During this process all the pieces of the curd should be kept in continuous
movement, and at a similar temperature. In the large American cheese-vats,
on the other hand, the whole mass of the curd, while it is being cut with
the curd-knives, maintains its condition unchanged for a long time, often
for thirty minutes, and even longer. The inside portions, and those
lying underneath, cool much more slowly than the outside portions and
those above, and the curd cannot possibly prove of uniform composition,
since it does not possess throughout the whole mass continuously the same
temperature.

The work of cutting must at first be conducted carefully and slowly,
and with the application of increasing force, as the thickening of the curd
progresses. If the necessary care and proper intelligence be expended, the
whey obtained is clear, and only contains ver\' few small pieces of curd.

Keevil has devised a special arrangement for cutting the curd in the
kettle. It consists essentially of an upright cylinder, set in motion by a
winch, to which four pinions are attached, with variously placed knife-
blades. It would appear that this unsuitable apparatus is destined to fall
into a well-deserved oblivion.

The subsequent heating should be carried on slowly and carefully, and
in such a way that each individual piece of curd may become uniformly
thick. If heating be carried on too quickly, the pieces become hard on
their surface only, and the outlet of the whey from the internal portion
is impeded or entirely hindered. Thus the mass of curd does not become
dry or uniform enough, and the cheese turns out badly.

The method of working in the cheese vessels in use in the preparation
of hard cheeses in Europe is more inconvenient and more troublesome than
the American method of making cheese in large vats, but it is undoubtedly
finer. It turns out, w^hen properly worked, -a curd of perfectly uniform
composition, and renders it possible to influence, as desired, the condition
of the curd up to the last moment before the formation of the cheese.

Before shaping, the curd is separated from the whey. "When a kettle
is used, this is generally effected in such a way that the curd at rest
under the whey is taken out of the kettle with cheese-cloths. The whey
is removed afterwards by draining, which is the simplest and best method.
In making cheese in vats, the whey is let off from the curd by means of a
tulie provided Avith a cork, which is placed under the vat, and care is
taken that the curd is retained as much as possible.

113. The Shaping of Rennet Cheese. — When the curd has assumed
the proper condition, it is removed from the cheese-vat, in order to

222 SCIENCE AND PRACTICE OF DAIRYING,

be formed into cheese. A few kinds of the smaller rennet cheeses
— cheese made from goats' or sheep's milk — are shaped by the hand.
Most kinds of cheese, however, receive their shape by the curd being
placed in suitable moulds without undergoing pressure, or by being
subjected to an external gradually increasing pressure, continued
until the single pieces are united together into a firm cohesive mass,
and until the curd has been separated as perfectly as possible from
the externally adhering whey. In the shaping of cheese, care should
be taken to secure that the entire mass of the curd which has to
form one cheese is perfectly uniform. If, for example, a very soft
fat cheese is to be made out of soft curd, obtained at a comparatively
low temperature, which is not equally fat in all parts, and after a
process of slow coagulation, if this be not cut, but be put directly
into the mould, all the mould should be filled at the same time, so
that in each mould there will be approximately the same quantity
of curd from the upper, middle, and lower layers. Finally, the
contents of each mould, after being filled, should be thoroughly
mixed. Furthermore, care should be taken that the whey run
uniformly from the fresh cheese, so that not more may remain
behind in one place than in another, and also that the whey which
is separated out from the cheese may run freely away. As long as
the cheese remains in the box, it should be often turned during the
first hours when the cheese is still quite soft, and less frequently
as the cheese becomes firm. By this turning of the cheese it is
sought to secure the equal distribution of its moisture.

The rooms in which the cheese are kept for days in the chests
should be neither too warm nor too cold, but should be maintained
at an equable average temperature. At a high temperature (20° C.)
active fermentation, accompanied with the development of gases, is to
be feared, which makes the cheese porous, and in the case of too low
a temperature (10° C.) the whey is not perfectly separated, a state
of matters which has a very bad efiect afterwards. Soft kinds of
cheese, which quickly ripen and which do not keep long, are made
in small moulds of different shape, while the hard keeping cheeses,
on the other hand, which ripen slowly, are made in larger round
chests, for which purpose chests made out of willow wood, or white-
metal or tin are used. If the cheeses have to be pressed into the
moulds or chests, they are wrapped up in cheese-cloths, and the
chests used are made of strong wood or of metal, with sides in
which holes are bored. When they have a bottom it is also perfor-

PRESSING OF RENNET CHEESE. 223

ated. The cylindrical moulds without floors, if they are not deeper
than about 10 centimetres, are not provided with holes, and are so
shaped that they can be placed either wider or narrower.

In England and America, the deep cylindrical-shaped chests, open
above and below, are provided with holes. They are made out of strong
white-metal, and are used in the manufacture of Chester, Cheddar, and
Dunlop cheeses. In Switzerland, in the preparation of round cheese,
round bent bands or strips of about the breadth of a hand are employed.
They are made of selected beechwood, Avithout holes, and are bound
together by a strong string, which permits of their being drawn closer or
opener as desired. In France, in the manufactiue of green cheese, round
bent bands made of zinc or white -metal are employed, Avhich like^vise
admit of being drawn narrower or wider apart, and which possess no
holes. In Holland, in the manufacture of Gouda cheese, bowl-shaped
wooden moulds, provided with holes, are used.

If the round cheese-moulds in which the cheese is pressed are to per-
form their function in a proper manner, they must be of a durable nature,
and must be so constructed that it can be at once seen if the discs betAveen
Avhich the cheese is pressed are not exactly parallel, so that the whey may
be allowed to flow away without hindrance, and the turning of the cheese
and the changing of the cheese-cloths may be easily and conveniently
effected.

The cloths which are used for -wrapping up the cheese in the moulds,
or for compressing them in the moulds, are specially woven out of strong
hemp yarn. In order that the whey may easily run off, and that the
cheese may quickly dry, these cloths must be coarsely woven (Avith a large
mesh). The yarn must not, however, be too coarse, and must be strongly
twisted, since in its use it is so completely soaked that the porosity of the
cloths is decreased.

114. Pressing" of Rennet Cheese. — The different kinds of soft
cheeses are either not pressed at all, or only very slightly, by laying
on weights, and Avithout subsequently increasing the amount of
the weight. There are, hoAvever, certain kinds of hard cheeses
which are not pressed, but Avhich are nevertheless A'ery firm and
dry. Hardness and dryness of the cheese is scarcely influenced by
the strength of pressure applied, but almost entirely by the method
in Avhich it is manufactured, and by the subsequent treatment of
the curd in the cheese-vat (fig. 70). The only object in pressing is to
facilitate the expulsion of the whey from the fresh cheese, and at
the same time to promote the cohesion of the single particles of the

224

SCIENCE AND PRACTICE OF DAIRYING.

70. — Wooden Cheese Vat to open
with Key.

curd, and to impart quickly to tlie cheese a smooth surface. It is quite
impossible to regulate the moistness of the individual small parts

of the curd by pressure. Pressure
merely effects the expulsion of the
whey which adheres externally to
the curd. It is only possible to
expel a very small portion of the
whey enclosed in the inside of the
curd particles, and in doing so a
small portion of the mechanically
enclosed fat is almost always ex-
pressed along with it. Pressure must always be carried out with
care and intelligence if it is to effect the desired end. The pressure
exercised should not remain the same during the whole period of

pressure, but should be
slowly and gradually
increased along with the
increase of firmness in
the cheese. If the cheese
be at first pressed too
strongly when it is still
soft, the curd on the sur-
face is pressed so firmly
together that the whey
enclosed in the centre
cannot be perfectly ex-
pelled, and the result will
be that the cheese re-
mains too damp, with the
consequence that it sub-
sequently becomes puffy.
The same thing happens
if the pressure be not
sufficiently great, or if in
using moulds which can
be adjusted, either nar-
rower or wider, the mould
is made too narrow, so that the top and bottom and pieces of the
cheese extrude between the hoops of the moulds and the pressure
boards, on which the whole weight of the press rests.

Fig. 71.— Tlie "Two in One" Double Cheese Press.

PRESSING OF RENNET CHEESE.

225

We have already spoken in the previous paragraph of the
necessity of frequently turning the cheese when in the press (fig, 71),
and of replacing the damp cheese-cloths with dry ones, and of regu-
lating the temperature of the surrounding air. The temperature of
the air should not be allowed to rise in the press-room over 20° C,
and should not be allowed to sink under 10° C.

The different kinds of cheese which are pressed only attain their
best condition if the amount of pressure has been properly applied

Fig. 72.— The "Gleed " Press for Soft Cheeses

from the beginning, and has been gradually increased up to a per-
fectly definite maximum, which must be determined exactly by
observation. As a rule, in cheeses having the same amount of fat,
a large cheese is more strongly pressed than a small cheese; while
a fat cheese is less strongly pressed (fig. 72) than a skim-milk cheese
of the same size. Cheeses are generally pressed somewhat more
in summer than in winter. Only cheese-
presses in the use of which it is possible to
carry out easily and conveniently the neces-
sary regulations for efficient pressing should
be regarded as good and useful. A good
cheese-press should act, above all, in such a
manner as to permit of continuous pressure
being applied, that is to say, should be so
constructed that the pressure can be easily
and gradually increased at will, and at the
same time it should show at any moment,

how much the total pressure is, and how many pounds of pressure
each pound of cheese is being submitted to.

The author prefers, to all other kinds of screw and box presses
used in America and in England, the lever presses of the improved
form made by Schatzmann (fig. 73), fitted with movable iron weights,

( M 175 ) f

Fig. 73.

-Swiss Lever Cheese
Press.

226

SCIENCE AND PRACTICE OF DAIRYING.

which are much used in Switzerland, Austria, and South Germany,
and which not only meet all requirements perfectly, but are both
easy and light to manipulate.

No doubt these lever presses require much space, and are, when
made as large as is required for pressing Emmenthaler cheeses,
somewhat heavy. This disadvantage, however, is of comparatively
little importance. In addition to the screw and box presses, iron
lever presses of an elegant apj)earance and occupying little space

Meter

Fig. 74. — Lever Press.

are used in England and America. Such presses are worked by
means of comparatively small and stationary weights in connection
with two lever poles working upon one another, and in this way
a great pressure is possible. These presses, however, are very dear,
are liable to rusting, and without doubt, in the matter of utility,
are inferior to the simple Swiss lever press.

A single lever with one arm furnishes the effective portion of the lever
press. The lever has its support point lying on the end of the lever pole.
The pressure, which is exercised by the lever through the action of a mov-
able weight attached, is easily calculated, by the law of levers, if the weight
of the lever pole be left out of account. The law of levers can be expressed
in a double manner, by saying that an equal weight is present on the lever
if the static momenta are equal to one another, or an equal weight is

THE SALTING OF RENNET CHEESE. 227

present if the force and weight are in inverse ratio to the arms of the
lever.

115. The Salting of Rennet Cheese. — A tew kinds of soft cheeses,
especially French soft cheeses, which are not allowed to ripen,
but are consumed in the fresh state, are salted only when eaten,
and not before. All other kinds of cheese are treated previously
with salt partly during ripening. The object of salting is to
render the cheese more pleasant in flavour, more easily digested,
and to enable it to keep better. Many other important advantages,
however, are obtained by salting. The salt, when in contact
with the fresh cheese, attracts moisture, and is converted into a
saturated brine, thus promoting osmotic processes in the cheese.
On the one hand, the dissolved salt penetrates into the interior of
the curd mass, and on the other hand, a liquid flows out of the curd
mass, which contains the constituents of whey in a state of solu-
tion, especially the milk-sugar, lime, and phosphoric acid. As the
author has shown by experiments, if the weight of the liquid which
flows out of the cheese mass in a certain time be larger than the
weight of the salt solution penetrating it, the result is that the salt-
ing process diminishes the percentage of water in the cheese and
makes the cheese drier. If the fresh cheese have from the first been
treated with an excess of salt, or if small quantities of salt have been
added to it for weeks or months at definite intervals, its percentage
of moisture can be either quickly or gradually diminished, and
in the latter case, according to desire or requirements. This is of
importance, since the activity with which the bacteria grow and
exercise their characteristic action depends upon the percentage
of water in the cheese, and because everything depends on the
condition that ripening should proceed quietly and at an equable
rate, and without any disturbing fermentations in the fresh cheese.
Since salt not merely diminishes the percentage of water in the
cheese, but also exercises a direct limiting influence on the action
of bacteria, two important advantages are offered by the salting
of cheese. In the preparation of very watery soft cheeses an
endeavour should be made, under all circumstances, to carry out the
salting as quickly as possible. This is effected by making the cheeses
of a small, comparatively thin, loaf shape, strewing them with
fine .salt, and keeping them during the salting, and immediately
afterwards, in specially constructed salt-rooms or drying-rooms.

228 SCIENCE AND PRACTICE OF DAIRYING.

Salt is added gradually, and in small portions, to the less moist,
fresh, hard cheeses of finer quality. This is done because large hard
cheeses, in which the osmotic processes go on more slowly than in
soft cheeses, do not harden equally throughout their mass, but
become harder on their surface than they are in the interior, if too
much salt be added at once to them. The hard cheeses require a
dry room, in which they must be allowed to remain until they have
become sufficiently dry to permit of their being removed to the
ripening-room or to the cheese-cellar.

Three diflferent methods of treatment may be employed, as a rule,
in practice, in salting cheese: (1) salting in a tub, (2) steeping in a
brine solution, and (3) strewing the cheese or rubbing the dry salt
into it.

Salting in a tub or steeping in brine is only resorted to in cases
of hard cheeses. All kinds of soft cheeses are treated outwardly
with dry salt, and the same is the case with the better and more
valuable kinds of hard cheeses.

For salting cheese, only good, dry, finely-grained salt, of pure
smell and flavour, should be used. If it be desired to have the salt
reduced to a very fine condition, it might be put through a salt-mill
before use.

With regard to the amount of salt required in the different kinds
of salting, no definite regulations can be laid down, owing to a want
of reliable observations. The least quantity of salt is used where
the salting is carried out in a tub; somewhat more when steeping in
salt brine is resorted to. With regard to the third method of salt-
ing, in the case of salting moderately heavy Emmenthaler cheeses,
according to the author's observations, the amount of salt used should
be about 6 per cent of the weight of the fresh cheese as removed from
the mould, and in the case of very large and very slowly ripening
cheeses of the same sort, more is necessary. In ripened cheeses the
percentage of salt may vary from 1 to 4 per cent, being on an aver-
age about 2 per cent.

Salting cheese in the tub or vat is effected by kneading into the curd,
with the hands, from 1 to 5 per cent of its weight of salt, before putting
into the mould. The salt is dissolved very quickly in the whey adhering
to the different small particles of curd, and removes water to a large
extent from the curd, so that in moulding and pressing a comparatively
large quantity of liquid runs off, and when it comes to be stored, the curd
has already become so dry that it can only throw off very little moisture

THE SALTING OF RENNET CHEESE. 229

into the air. As a rule the cheese is not further salted in the store, but is
turned from time to time and brushed dry Avith a brush. Although this
method of salting, in which the required quantity of salt which it is neces-
sary to add to the cheese is added all at once, is very simple, it is only
customary to use it in the preparation of certain kinds of cheese, since it
excludes a more lasting and absolute action on the process of ripening
of the cheese. It is only adopted in Europe in the preparation of poor
hard cheeses of little value, the preparation of which is carried out in the
cheapest and simplest manner. Often, however, it is used in British and
American cheese factories even in the manufacture of fatty hard cheeses,
when manufactured on a very large scale.

In steeping cheese in brine the cheese is left for from three to four days
time in a saturated salt solution, is turned twice daily, and the upper surface,
which rises above the salt solution, is quickly strewn each time Avith salt,
care being taken that some undissolved salt is lying on the floor of the
wooden steeping-trough. The saturated salt solution is renewed every
eight to fourteen days, and is prepared by dissolving two parts of common
salt in four parts of water. One hundred parts by weight of water at the
ordinary temperature dissolve thirty-six to thirty-seven parts by Aveight
of salt. In this treatment a layer is formed on the surface of the cheese
1 to 1*5 cm. thick, Avhich becomes saturated Avith salt. This salt, if the
cheese be not too large, that is, not over 15 kilos, in Aveight, is gradually
distributed by osmosis throughout the Avhole cheese mass. According to
the author's experiments, fat and skim-milk cheeses Aveighing betAveen 7
and 15 kilos, lose, on being steeped for four days in a brine solution, five
to six per cent of their Aveight. The cheeses A\'hich have been steeped are
not further salted in the store, but are regularly turned, and perhaps
washed from time to time with a dilute solution of salt. A fresh mass of
cheese loses less moisture Avhen it is steeped than Avhen it is salted in the
cheese-vat. Those cheeses, therefore, Avhich have been steeped, keep both
softer and damper than those Avhich have been salted, in the vat. Large
hard cheeses, especially skim-milk cheeses, easily acquire, by means of the
steeping, a very hard outer crust, Avhich becomes detached from the inside
softer mass as soon as the cheese has been cut for only a feAv hours, and
left lying in a dry place. Many hard cheeses, Avhich are treated for some
time on the outside Avith dry salt, aie finally left for tAvelve to tAventy-four
hours in a salt solution, chiefly for the purpose of giving them a hard rind.

In the third method of salting, the cheese is streAvn Avith salt on its
surface, or the salt is rubbed in. This is done at regular definite intervals,
at first daily or every second day, and subsequently less frequently, and
finally only Avhen necessary. Salting is begun either immediately after
the cheese has been removed from the mould, or after the lapse of tAvo

230 SCIENCE AND PRACTICE OF DAIRYING.

days, when the cheese has become dry to a certain extent. In this method
of salting, the important thing to be aimed at is to salt the entire surface
of the cheese as equally as possible. This is efl'ected by turning the cheese
before every new salting, and, as soon as the salt is perfectly dissolved, by
brushing the brine, with a brush especially designed for this purpose, over
the surface of the cheese, and by rubbing the sides of the cheese more
frequently with the salt than the top or the bottom. The cheese should
not be turned till its surface has become sufficiently dry. As long as it
yields an abundant brine, the cheese is kept in a special room — the salt or
drying room, — care being taken that the brine is allowed to drain quickly
off from the cheese. During this period, the fresh cheese is so saturated
with water, and is so soft, that special precautions must be taken to main-
tain its regular shape. For this purpose rectangular small cheeses are
laid on their ends in a row close to one another, and large round cheeses
are surrounded with a wooden hoop similar to the hoop of the mould, or
are firmly sewn up in a strip of cloth (England and America). As soon as
the surface has become sufficiently hard the cheese has its wrapping
removed, and the salting is carried out. Finally, Avhen the salting has
been practically completed, the larger cheeses are rubbed over from time
to time with a cloth dipped in a salt solution, and the smaller cheeses are
dipped once or twice into sour whey or a solution of salt. The method of
salting is determined by the special conditions of the different kinds of
cheese; the temperature and the relative dampness are regulated similarly,
according to the nature of the cheese to ])e manufactured.

In order to permit sufficient time for the osmotic processes taking
place in this method of salting, the salting process and the drying process
are caiTied out very slowly and gradually, so that the cheese may become
of similar character throughout its entire mass, a point of the highest
importance for the process of ripening. The drying and hardening of the
cheese may be facilitated or hindered by salting more strongly or more
weakly, according to the circumstances and necessity, and thus the progress
of the process of ripening may be influenced. In order to ascertain this
correctly, it is necessary to watch carefully the ripening of the cheese in
the store, and not to delay boring or cutting into the cheese, and examin-
ing a small portion of its interior.

In the case of small and light cheeses, the method of salting under dis-
cussion possesses the disadvantage that it is very laborious and consumes
much time, and, at least in the case of large valuable hard cheeses, as,
for example, the Emmenthaler cheese, demands much practical skill and
attention, as Avell as a certain expenditure of force. On the other hand, in
addition to the great advantages already enumerated, it possesses the re-
commendation that the cheese has only a thin external rind or skin, that

THE RIPENING ROOMS OF RENNET CHEESES. 231

the destructive process of fungoid formation cannot take i)lace in the cheese
surface, and that, through the operations daily cai-ried out in the cheese-
cellar, attention is attracted in the course of the many observations made
to any unusual behaviour on the part of the cheese, and any necessary action
can then be taken without delay.

116. The Ripening -rooms of Rennet Cheeses (Cheese Cellars or
Rooms). — From the drying-room the cheese is brought into the
ripening-room, in which the process of ripening, which has already
been started, and which has gone on to a greater or less extent, is
carried to a conclusion. For cheeses which ripen quickly one
ripening-room is sufficient, but for those which have to lie a long-
time the ripening-room should be divided into two portions, one for
the fresher cheese, and the other for the partly ripened cheese. In
the rooms in which the fresher cheeses are kept, the temperature of
the air should be maintained somewhat higher than that of the air
of the other ripening-room ; but it need not remain exactly equable,
though it ought not to be allowed a wide variation. The percentage
of moisture should amount to about 85 to 90 per cent of the moisture
the air can hold. The room should also be well ventilated, because
moisture is constantly evaporating from the cheese. On the other
hand, in the rooms for the ripening of the older cheeses, the tem-
perature of the air must be kept as equable as possible, and com-
paratively low; while the percentage of moisture should be always
from 90 to 95 per cent. The most favourable conditions for the
ripening of newer and of older cheeses are between the temperatures
of 10'' and 20° C. Within these limits, a higher temperature is
chosen for a more quickly ripening cheese than for a very slowly
ripening cheese, and similarly a higher temperature is required for
skim-milk cheese than for fat cheese of tjie same sort. If the tem-
perature be allowed to rise over 20° C, ripening takes place more
quickly but less uniformly, and the result is a large percentage of
badly-made cheese. When exposed for some time to the influence of
temperatures below 10° C, it has been found in practice that in the
case of all cheeses undesirable changes take place in the ripening
process. The temperature and the relative moisture of the air
should be intelligently watched and daily noted, on account of the
great influence which these external conditions have on the process
of ripening. For this reason no ripening-room should be without
a thermometer, and an instrument for measuring moisture — a hygro-
meter.

232 SCIENCE AND PRACTICE OF DAIRYING.

The stands on which the cheeses are placed in the ripening-room
are made of wood. They are adapted to the form of the cheese, and
the boards should be made of unpolished wood, and so wide that
there is plenty of room to rest the whole surface of the cheese on
them.

Flies of all sorts must be excluded from the ripening-room.
Especial care should be exercised in this respect in the rooms in
which soft cheeses are ripened. In soft cheeses, the larvae of differ-
ent kinds of flies are apt to become embedded, especially during
summer, in the months of July, August, and September. This is
more especially the case with those of a common cheese-fly (the Pio-
pJiila casei). As cheeses in which the larvae of flies are embedded
ripen more quickly than other cheeses, such cheeses should be sold
as quickly as possible — a practice which is not without risk. The
best method of protection against such risk is to take precautions
which are not difficult to carry out, to exclude flies altogether from
the ripening -room. If, however, it is desired to destroy the larvae
which may have lodged in cheese, the best method is to dip the cheese
repeatedly in a lukewarm strong liquid extract of common pepper.

In all hard cheeses which have been carelessly treated in the
store-room, the common cheese-mite (Acarus siro) occurs often in
enormous numbers, and in time converts the dry cheese mass into
a powder made up of the excrements and skins of the mites casting
their skin. In fresh dry hard cheeses they dig shallow passages
or holes in the rind. Their action is less harmful than that of the
cheese-fly, and they may be easily destroyed by rubbing the cheese
over several times with oil, or with strong solutions of salt or spirits
of wine, and by brushing the cheese-stand with soapy water.

Poisons, for the destruction of rats and mice, should on no
account be used in cheese-cellars.

Up till the year 1880, the arrangement of the ripening-rooms for cheese
manufacture was very unsatisfactory in Austria and throughout Germany,
and even in Switzerland, where it would be least expected. It was best in
France, in the cheese dairies in which the finest French soft cheeses were
prepared. Heating was effected only through ovens — in many cheese-
cellars even iron ovens. Of special ventilating apparatus none were known,
and the relative percentage of moisture in the air was increased and main-
tained at the desired amount by the primitive method of introducing steam
occasionally into the ripening-room. Such an arrangement was that of
Pfister-Huber, for example, who introduced into Switzerland, at the begin-

THE RIPENING ROOMS OF RENNET CHEESES. 233

ning of the year 1880, a method which he had devised of treating round
hard skim-milk cheeses. The unsatisfactory arrangement of cheese-cellars
not only increased the difficulty of treating the cheese in the store-room,
but also the Avhole manufacture of the cheese, inasmuch as it Avas necessary,
if it Avas Avished to aA'oid serious mistakes, to take many precautions, in
the i3reparation of the cheeses in the cheese-rooms, against the harmful
influences to Avhich they Avere subsequently exposed in the cheese-cellars.
At present, in the ripening-rooms of all the larger and better equipped
cheese factories, steam and Avarm-Avater heating apparatus are proA'ided, as
Avell as apparatus for regulating the ventilation. Quite lately W. Helm, a
civil engineer, has attempted to perfect the arrangement of the ripening-
rooms for cheese manufacti;re. In the first place, according to him, it is
advisable to build the cheese-cellars either Avithout Avindows, or to provide
them Avith very feAv and veiy small AvindoAvs. The fcAver AvindoAvs j^resent,
the more independent is one of the conditions of Aveather, and the easier it
is to maintain the tempcratvu'e and relatiA'e moisture equable throughout
the Avhole year. Further, he Avould lead through the cheese-cellar, already
provided Avith a Avarm-Avater heating apparatus, a continuous stream
of air, saturated Avith Avater vapour, at a temperature of about 10° C,
before its entrance into the cellar, in a room specially constructed for this
purpose. The stream of air can be increased or diminished as desired. It
enters the cellar up above in the neighbourhood of the roof, passes
over the heating tubes, and is Avarmed by them, and by this Avarming
loses someAvhat in its percentage of moisture. It travels through the
cellar, and finally leaves it by means of canals AA'hich haA'e their exits near
the floor. By due regulation of the rapidity of the current of air and of
the heating, it is possible not merely to bring the temperature and the
moisture of the air to exactly the desired condition, but also to maintain it
equally at the desired temperature. Up till noAV only a feAv cheese-dairies
have been provided Avith this arrangement. Unfortunately it is someAvhat
costly, and on this account it has not come into general use, Avhile reliable
details in regard to its efficiency in Avorking for a prolonged period, and
its technical and economic value, liaA'e not yet been furnished. Every im-
pi'ovement of the ripening-rooms for cheese manufacture must be regarded
as an advance in the interests of dairying.

By the relative percentage of moisture of the air, is understood the
amount of the moisture, expressed in per cent, Avhich the air under the
existing temperature and barometric pressure is able to absorb and become
saturated Avith. For example, a relative percentage of moisture of the air
of 75 per cent, Avould indicate that the air under the existing conditions of
temperature and air pressure only contains three-fourths of the Avater
vapour Avhich Avould be required to bring it to the point of saturation.

234 SCIENCE AND PRACTICE OF DAIRYING.

117. The Art of Cheese-making. — The art of cheese-making is
much more difficult than that of butter-making. In cheese-making
a laro'e number of different conditions have to be reckoned with, and
their different influences have to be considered and weighed in rela-
tion to one another, so that they may all conduce to their definite
and prescribed end. To do so requires a certain measure of skill
and experience. He who understands how to manufacture suc-
cessfully even one kind of fine cheese, in different places, that is,
under different surrounding conditions, will also assuredly succeed,
after a short amount of tuition or intelligent description, in the
manufacture of other kinds. The art of cheese-making requires two
different qualifications — a clear understanding, on the one hand, of
the nature and action of all the processes which come into play in
the manufacture of cheese; and, on the other hand, the particular
object which must ever be kept in view in all these processes, and in
the manufacture of all kinds of cheese.

There is no doubt that the different kinds of cheese owe their
particular properties or characteristics to the action of different
definite bacteria, or classes of bacteria. Since it is possible to prepare
any kind of cheese from a given quantity of milk in a given place
or at any time, and according to its nature to obtain it from this
milk, it follows that all the kinds of bacteria which are necessary
for the manufacture of the cheese in question must be present uni-
versally and invariably in the milk. These bacteria must have an
extraordinarily wide occurrence. The art of cheese-making consists
in the preparation of the fresh cheese mass of each different kind
in such a way that those kinds of bacteria which are active in the
ripening of that particular cheese must be developed to a predomi-
nant extent. It is on this account that cheese-making employs the
most various means. In the first place, the separation of the milk
may be effected by acids or by rennet. In the preparation of rennet
cheeses, it is in the power of the operator, according to the methods
and kind of coagulation effected in the milk, to produce a curd harder
or softer, and, according to the state of division, to make it damper
or drier: to determine, by regulating the percentage of fat in the
liquid which is being converted into cheese, the structure of the curd ;
by subsequent heating to different high temperatures to lessen the
percentage of moisture in the curd according to requirements; to
weaken the energy of the development of the more susceptible kinds
of bacteria; by the application of high temperatures, in the process

THE ART OF CHEESE-MAKING. 235

of subsequent heating, and by pressure, to regulate the amount of
whey remaining in the cheese between the small particles of curd;
and by salting to reduce, more or less slowly, to the necessary smallest
quantity, the percentage of moisture in the fresh cheese. But this
does not exhaust the means used in cheese manufacture by which it
is possible to control, to any desired extent, the most varied condi-
tions. It is possible to prevent from the very lirst the growth of a
large number of bacteria, and to direct the ripening into a particular
direction, by attempting to maintain the curd in a perfectly sweet
condition; or by imparting to it from the very first a sour reaction,
by the addition of sour liquids to the milk to be converted into
cheese; or by souring it after it has been put into the cheese-vat;
or by letting it ripen; or by saturating the curd mass before it is
put into the mould with liquids containing rapidly -developing
cultures of certain kinds of bacteria, as is done in the preparation of
certain kinds of Dutch cheese.

In these processes, which up to the present time have been carried
out in practice by instinct, as it were, and wholly on the basis of ob-
servation and experience, it must always be felt that the success of all
the operations is connected with one indispensable qualilication, viz.
the qualification of the very highest importance, that in cheese-making
it is necessary to start prepared to exercise in all the operations
constant care and attention. This qualification consists in conduct-
ing each operation, whatever it may be, in such a manner that the
entire mass of curd may become throughout of a perfectly similar
condition. The author has not failed in the foregoing pages, in
describing the individual processes of cheese manufacture, to empha-
size this fact. It has long been shown in practice that the equal
development of the ripening and successful results can never be
expected if the cheese mass be not perfectly uniform in quality
throughout. If this condition be neglected, the result will be
disastrous, especially in the case of the manufacture of large cheese,
of which only one or two separate cheeses are made at one time.
Whoever recognizes, perfectly or clearly, the great importance of
this qualification, has grasped to a certain extent the secret of
cheese manufacture, and has found the key to a proper understand-
ing of all its rules. If this idea be once fully realized, and if the
rules above described, which have been given for the manufacture
of cheese, be put to the test by accurately- following them, it will be
found that they inevitably lead to satisfactory results.

236 SCIENCE AND PRACTICE OF DAIRYING.

118. The Ripening of Cheese. — The chief constituent of all fresh
cheese — the paracasein — is only very slightly soluble in water. It is
on this account that fresh cheese, unless it be in a perfectly soft,
almost gelatinous or buttery condition, is not enjoyable or palatable.
In order to render it palatable, it is allowed to ripen, that is,
it is kept under suitable conditions (§ 116) till decomposition of
its constituents, which takes place as soon as the bacteria present
in the cheese mass are cultivated and developed, is permitted to go
on for a certain time. When this limit is reached the cheese is
known as ripe. Ripe cheeses of any kind, which have been kept
for just the proper length of time, possess the best flavour and the
highest value which the kind of cheese can attain to.

The most important process, in the ripening of cheese, is the
change which the paracasein undergoes. From this chief constituent
of the cheese simple compounds are formed, which are soluble in
water; then compounds which resemble, and which are akin to the
albuminoids. Among these, peptone, probably also caseo-glutin,
subsequent numerous further products of decomposition, among
which are amido acids, phenol-amido proprionic acid, and leucin and
tyrosin, have been identified, and finally ammonia salts. The soluble
bodies which are held in the water present in the cheese, determine
by their quantity and condition the flavour of the cheese, and alter
the appearance and consistency of the cheese mass by penetrating
through its pores.

Milk-sugal% which is only present in fresh cheeses to a small
extent, quickly vanishes under all conditions. It is either entirely
converted into lactic acid, from which further decomposition pro-
ducts— for example, butyric acid — may be formed, or it is changed
into a form of fermentable sugar, and then gives rise to a remarkable
fermentation, accompanied with development of gas. This fermenta-
tion is effected by bacteria, and yields, in addition to small quantities
of alcohol and other substances regarding which we know nothing,
chiefly carbonic acid, which is produced in large quantities, and
hydrogen. With regard to this interesting phenomenon, as well as
with regard to the formation of bubbles in the cheese, investigations
are at present being carried out, which will doubtless very soon furnish
more exact information. In what way the conversion of milk-sugar
and its products influences the other processes of decomposition
taking place in the cheese mass, or acts upon the digestibility and
the condition of the cheese mass, or the flavour of the cheese, we

THE RIPENING OF CHEESE. 237

cannot as yet say. It is highly probable that the milk-sugar
generally, if not perhaps entirely, directly causes the formation of
all the pores in the cheese, the small and very numerous holes in
the American, English, Dutch, and other hard cheeses, as well as the
holes about the size of beans which are unconnected but regularly
distributed in the Emmenthaler.

The fat is very little affected to all appearance by the decom-
positions going on in the ripening cheese mass. At any rate, in no
case do the products of fat decomposition exercise a noticeable
influence on the characteristic properties of the different kinds of
cheese. Probably the only influence which, the fat exerts on the
characteristic nature of the cheese is in affecting its pleasant flavour,
and the tenderness and softness of the cheese. These properties de-
pend on the quantity of fat present. It is not impossible that the fat
hinders and retards, according to the amount in which it is prasent
in fat cheeses, the action of the albumin bacteria on the paracasein.

Of mineral constituents of the cheese, a portion, esj^ecially lime
and phosphoric acid, are lost by passing away with the salt, in the
salting of the cheese, by the process of osmosis. Whether, and to
what extent, the mineral salts are directly or indirectly split up by
the growth of bacteria in the ripening processes, is not known.

The percentage of water in the cheese becomes distinctly less
during ripening. A portion of the water evaporates or flows away
in the salting of the cheese with the salt solution, and another
portion is lost by the water forming in the ripening process new
combinations, and entering into chemical combination.

The slowly-ripening hard cheeses do not appear, during the
ripening process, to suffer any appreciable further loss of weight,
unless by that due to loss of moisture. Up till now, at least, it has
not been discovered that any loss of the volatile ammonia salts,
volatile fatty acids, or methylamine occurs. On the other hand,
it is highly probable that the rapidly-ripening soft cheeses, posses-
sing a penetrating odour, suffer a loss of their organic substance.
What constituents of the cheese are decomposed in these losses, and
in what way the loss takes place, is not yet known. It has also not
yet been demonstrated with certainty that there is a development
of small quantities of iiidol and skatol in the ripening of cheeses
possessing an odour, nor has it been ascertained whence the free
butyric acid is derived, which it has been proved is invariably
present in ripening cheeses, and which is present, in large quantities,

238 SCIENCE AND PRACTICE OF DAIRYING.

in ripening soft cheeses. The lactic acid derived from milk-sugar
cannot be the sole source, and hence it must be assumed that, in the
decomposition of albuminoids, butyric acid is also formed. It seems
to be certain, at any rate, that it is not formed from the fat of the
cheese.

The much-discussed question, as to whether in the ripening of
different kinds of cheeses the percentage of fat in the cheese
increases, that is, whether in the ripening process neutral fat can be
developed from albuminoids, which is not inconceivable, has not yet
been satisfactorily nor assuredly decided. If such a formation
actually takes place, it probably results in a synthetic manner from
the combinations which are effected by the action of bacteria on
the albuminoids. Nor is it inconceivable that small quantities of
neutral fats may be derived from the lecithin of the butter-fat.
Interesting as this question in itself is, it does not possess any
practical significance, since, under any conditions, it can only give
rise to the formation of comparatively small quantities of fat.

The author does not regard it as probable that in the ripening
of rennet cheese the rennet used for coagulating the milk exerts
any subsequent influence.

It will be observed that the development of certain kinds of
micro-organisms concerned in the ripening of cheese is adversely
affected by light. It is to be recommended, therefore, in all cases,
that the rooms in which the ripening processes are carried on
should be kept dark, and that they should possess very few
windows — a point which is advisable on other grounds, already
stated in §116.

The peculiar characteristics of the numerous different kinds of
cheeses depend on the progress of the many processes, some veiy
complicated, which have been here shortly described. The older
researches on the chemical changes which the caseous matter suffers
in ripening contain little that is worthy of note. On the other
hand, the elaborate and exact researches carried out by E. Schulze,
U. Weidmann, B. Rose, and F. Benecke on the ripening of Emmen-
thaler and some other kinds of Swiss cheese, supply very interesting
glimpses into the process. These may be shortly epitomized as
follows: —

In ripening and in ripe cheeses of the kinds mentioned, in addition to
unchanged paracasein, and in addition to at least one characteristic nitre-

THE RIPENING OF CHEESE, 239

genous body similar to caseo-glutin, of which more is not known, there is
found a body which stands in its properties between albuminoids and
peptones; further, leucin, combined with amido acids in comparatively large
quantity, as Avell as tyrosin and phenol-amido proprionic acids — the last
tAvo in smaller amounts — and, finally, ammonia, but in very small quan-
tities, are all developed. Of ammonium magnesium phosphate, lactic acid,
butyric acid, and peptones, ripening cheeses contain only small cpiantities.
Only Facherin and Bellelay cheeses have been found comparatively rich in
peptones. The loss of their substance Avhich the ripening cheeses suffer is
only very slight. That the older the cheeses become the greater are the
amounts of the albumin decomposition products, Avas shown by the advance
made in the ripening processes with the lapse of time. Milk-sugar is not
present in ripe cheeses, nor are xanthin bodies found in them. A separa-
tion of fat only takes place in very small quantities, and the increase of the
percentage of tri-glycerides in the cheese is not noticeable. Whether free
non-volatile fatty acids are present in cheeses could not be decided. It is
not impossible that the different caseo-glutins, which do not perfectly
agree with one another in their physical behaviour, are present in the
different ripe cheeses, and it appears very probable, from this fact, that
nuclein is gradually decomposed in the ripening process. In ripe Emmen-
thaler cheeses, on an average, about 80 per cent of the entire amount of
nitrogen belong to bodies of an albuminoid nature, and 20 per cent to
products of the decomposition of albumin. In skim-milk cheese, prepared
after the manner of Emmenthaler cheese, the changes taking place in the
material of the cheese in the ripening process are not exactly the same as
those taking place in the fat cheese. The watery extract is richer in
albumin, and poorer in albumin decomposition products. The latter also
shows a higher percentage of nitrogen than the fat cheeses. The extract
of skim-milk cheeses leaves behind, Avhen strained, a very unpleasant-
smelling residue.

The above-mentioned researches chiefly concern themselves with
the chemistry of ripening. On the other hand, the researches of
Cohn, Benecke, and Duclaux deal chiefly with the study of the
ferments concerned in the ripening of the cheese, and are bacterio-
logical in their nature. Duclaux describes a number of enzymes
which are separated by bacteria, and which co-operate with them in
the ripening of cheese. The bacteriological experiments which have
been carried out on the ripening of cheese have partaken of the
character of preliminary experiments only. They have merely
dealt with the surface of the subject, and have not been at all
exhaustive. Nevertheless, they have been very serviceable in

240 SCIENCE AND PRACTICE OF DAIRYING.

opening up a new point of view, and they have pointed to the way
along which light on the process of the ripening of cheeses will be
gradually obtained. This way lies in the closely intimate relation
that exists between the investigations of bacteriology and chemistry.
To begin with, systematic attempts have been made to discover by
means of these two sciences what kind of bacteria are at work and
in what way the chief phenomena are brought about, as, for ex-
ample, the change of paracasein, the change of milk-sugar, and the
formation of holes in the cheese; also what effect bacteria and the
lower forms of fungoids have on the fat, &c. It may perhaps be
soon proved that the processes taking place in the ripening of
cheese are neither so complicated in degree, nor so many-sided, as
we are at present inclined to think.

The functions performed by the lower fungoids in the manu-
facture of cheese have been previously discussed in § 43. As has
already been mentioned, it must be assumed that milk universally
and invariably contains all the different kinds of bacteria which act
in the manufacture of cheese. It has also been already pointed
out that fresh curd resembles to a certain extent a field which is
richly sown with the most varied kinds of bacteria, but on which
no kind of bacterial vegetation is permitted at that stage to pre-
dominate. If it be observed that the milk of individual cows, or
the milk of a whole herd, has proved itself useless for the manufac-
ture of cheese, since, when utilized for this purpose, even with the
observance of the greatest care and with the most intelligent work,
certain phenomena of ripening take place prematurely or in a
disturbing manner, or the flavour of the cheese is unpleasant,
or there is any other failing manifested, the author is inclined
to believe that this does not, as a rule, arise from the fact that the
milk has become contaminated with peculiar bacteria not generally
present. Such phenomena are probably rather to be traced in most
cases to the fact that some of the common sorts of bacteria of milk
have developed with special luxuriance, and have changed the
properties of the milk to a certain extent, a state of matters which
has adversely influenced the development of the other common
kinds, and has given the ripening process an undesirable direction.
It must not, however, be denied that occasionally strange kinds of
bacteria, which have nothing to do with the ripening of cheese, find
their way into the milk, and are thus able to disturb the manufac-
ture of the cheese. Milk, when it is coagulated, ought not, as a

THE RIPENING OF CHEESE. 241

rule, to contain any one-sided predominating bacterial vegetation;
but this can only be secured if the milk has been obtained from
healthy cows, and if in the process of milking, as well as afterwards,
everything has been done in a clean and careful manner. If distur-
bances should arise in milk derived from different herds in a cheese
manufactory, and it be desired to discover from what herd the
milk which is unsuitable for cheese-making has been obtained, this
may often be effected by the application of the milk fermentation
test or the rennet test described in § 33.

It is by no means always easy or simple to conduct and regulate
the many different operations of cheese-making in such a manner
that the cheese manufactured from day to day will be of equally
good quality. Occasionally influences have to be dealt with which
defy all precaution; for example, the dealing with milk which is
unfit for the manufacture of cheese. It is therefore quite impossible
in cheese dairies, even in the best of them, to avoid turnino- out,
along with the more or less successful cheeses, a greater or less
percentage of failures. The causes which lead to failures in the
manufacture of cheeses, and which thus damage the cheese indus-
try, may be of very different kinds. Against a few of them there
is scarcely any safeguard. The most of them, however, and those
which are of most common occurrence, may be combated by the
exercise of the requisite amount of attention and skill.

The commonly occurring disturbances and defects in cheeses are, for
example, as follows : —

(1) Those common to all sorts of cheeses. The cheese becomes inflated,
owing to the fact that the process of ripening takes place too soon, and
proceeds at too rapid a rate, a defect which may be generally, if not
always, overcome.

(2) In soft cheeses the cheese runs, that is, it loses its shape, and is
changed into a sticky, gelatinous mass (refractory), a defect which is the
result of too quick ripening, and can always be avoided.

(3) In soft cheeses the cheese becomes the prey of flies, which can
always be prevented.

(4) In hard cheeses, the formation in certain places on the surface of
the cheese of fungoid growths, Avhich convert the cheese into a dry white
powder, so that gradually larger or smaller holes are formed, beginning on
the surface of the cheese. This is always preventible.

(5) In cheeses of all kinds, the occurrence in the cheese of a bitter or
a soapy flavour. This is a rare occurrence.

( M 175 ) Q

242 SCIENCE AND PRACTICE OF DAIRYING.

(6) III hard cheeses, the formation on the surface of the cheese of red
patches, or the coloration of cheese in blue or yellow patches, or the
discoloration of the entire mass of the cheese, so that it presents a bluish-
gray or black appearance. This happens veiy rarely.

(7) In soft cheeses and sour-milk cheeses, the development of poisonous
properties in the cheese. In cheeses which have ripened too quickly, or
which have become overripe, certain kinds of bacteria develop, which give
rise to the formation of toxines. The cheese exercises poisonous effects,
and when eaten causes the development of symptoms, such as are seen in
gastro enteritis toxica or in cholera nostras. Poisoning with old cheese is
very rarely accompanied with fatal results.

Again, almost every kind of cheese has its special disease. To go into
these even shortly would lead us far afield.

The chief expense in cheese-making is due to the ripening.
Apart from the loss in weight which the ripening cheese suffers, and
the waste which this causes, the treatment and supervision of ripening
cheese demand the expenditure of much time and labour, and the
capital which is invested in the manufacture of cheese is locked up
through the long period during which ripening lasts. By making
the curd less dry, and by raising the temperature of the air in the
store-room, the ripening period may be considerably shortened, but
this can only be effected at the expense of the average good quality
of the cheese. This practice would prove practically advantageous
only under exceptional circumstances, as in the case of a very exten-
sive trade, and even then it would have to be carried out with very
great care. As a rule, the loss incurred from the production of a
number of spoiled cheeses would be greater than the saving effected
on the cost of manufacture. As a rule, the best course, from an
economical point of view, is to take precautions to secure a slow and
equable progress of the ripening, and not to depart from the average
period, which must be regulated as experience has shown to be best,
if the cheese is to acquire the best possible condition. In all fermen-
tation processes the best and finest results are obtained from the
processes that require comparatively the longest periods of fermen-
tation.

In order to prepare cheeses of different kinds for the market, they
are subjected to special treatment, partly during the ripening process and
partly later. They are scraped and brushed, their surface is polished,
and is coloured with annatto, turnesol (Crozophora iinctoria), and other
colours, rubbed over with oil, wine, beer, extracts of leaves, &c., are ironed,

DIFFERENT KINDS OF CHEESE AND THEIR CLASSIFICATION. 243

that is, a hot iron having a flat surface is run over them in order to give
them a horny surface, or they are smoked in the smoke of firewood. In
these operations, the object aimed at is to attempt to improve the apjjear-
ance of the cheeses, and also their keeping qualities.

Small soft cheeses, with oily surface, which possess a sharp smell, are
packed in tinfoil. The covering of tinfoil gives to the cheese not merely
a better appearance, but facilitates the keeping of it, and makes its retail
sale pleasanter, since it keeps the soft cheeses firm, and retains the pene-
trating odour. As, however, the tinfoil used in commerce often contains
as much as 20 per cent of lead, the question arises as to whether the packing
of cheese in tinfoil containing a large quantity of lead does not threaten
the health of the consumer. Experiments carried out on this subject, have
proved that cheeses which have been packed in tinfoil, containing a high
percentage of lead, only contain lead on the outer portion of their rind, and
that the percentage of lead in this portion is only '5 per cent, and that a
short distance inwards from the rind no lead can be detected. If, there-
fore, the precaution be taken not to eat the rind of cheeses which have
been packed in tinfoil, there is no ground for fear on this account.

A sample of tinfoil has been found to contain

Tin, 96-21

Lead,
Copper,
Nickel,
Iron^

2-41
•95
•29
•09

99-95

In Algau, in Bavaria, it is customary, in the case of brick-shaped
cheeses, to pack them when they are only a quarter ripe, the cheese being
first wrapped up in firm unglazed paper, and then in tinfoil. A skilled
cheese-maker can wrap up in an hour 80 to 100 separate brick-cheeses in
tinfoil.

The pi-eparations for hastening the manufacture of sour-milk cheeses,
introduced by Trommer in 1846, which consisted in treating the curd Avith
ammonia, carbonate of ammonia or soda, in order to give to the fresh cheese
the appearance of old and regularly-ripened cheese, need only be mentioned
here as an historical curiosity.

119. The Different Kinds of Cheese and their Classification. — Of
the very large number of different cheeses now known, a not incon-
siderable portion were known to the nations of antiquity. Fresh
whey and fresh watery cheese were partaken of in very early times,
several thousand years before the beginning of our era. Certain

244 SCIENCE AND PRACTICE OF DAIRYING.

methods of treatment were also known by means of which the
cheese could be made to keep longer. Probably it was cheese made
from sheep's or goats' milk, no doubt sour-milk cheeses, that were
first prepared in the olden times. Martini and Hornigh have selected
a number of notices, from which they infer that the knowledge of
cheese is a very old one, and that men early came to prize the
manufacture of cheese, and devoted great attention to the pre-
paration of the different kinds. Aristotle (384-322 B.C.) wrote
concerning the use of different kinds of rennet, and in Varro
(115-25 B.C.) we find descriptions of the influence of bulling, of age,
of food, and other conditions, on the properties of the milk of the
different mammals, and the cheese manufactured therefrom. In
Pliny (23-97 A.D.) we learn that in his time a long catalogue of
different kinds of cheese was drawn up, and Columella, who lived in
the first century A.D., already wrote on the influence of temperature
on the thickening of milk with rennet, of the necessity in the
pressure of cheese of gradually increasing the pressure in the cheese -
moulds, of salting with dry salt, and of salting with brine, of smoking
cheese, and of the preparation of herb cheeses. From the writings of
Roman authors, we further know that in many districts in the
middle and south of France, for example, in the present depart-
ment of Aveyron, in which Roquefort is situated, cheese was pre-
pared and sent to Rome in the first centuries of our era. The
oldest reliable records of German cheese-making belong to the time of
Charles the Great. At that time, it would appear that the prepara-
tion of cheese was regarded as more important, and was carried on
in a wider area, than the preparation of butter. The most thorough
understanding of the art of cheese-making generally, and of the
nature and importance of all the operations which it involves, is
to be found in Switzerland, as is proved by the fact that the Em-
menthaler cheese, which is the finest of all kinds of cheese, and the
preparation of which in perfect condition is more difficult than the
preparation of any other kind of cheese, is made there.

In the following paragraphs the author will attempt to enumerate
shortly the different kinds of cheeses. A complete description of
the preparation of all of them is naturally not possible in this
work. The author will rather describe in fuller detail the process
of the manufacture of certain kinds of cheeses, in order to illus-
trate the general principles of cheese manufacture. Such cheeses
as are universally known and esteemed will be selected, and such

DIFFERENT KINDS OF CHEESE AND THEIR CLASSIFICATION. 245

as ni&y, at the same time, be regarded as typical, to a certaiu
extent, of the larger groups of cheeses. He limits himself to this,
because he doubts if a more detailed description, unless it went into
all characteristics in an exhaustive manner, would possess any practi-
cal value. It is not possible from a short summary and description
to prepare, with good results, new foreign kinds of cheeses. This
can only be effected by studying the manufacture locally, or by
having at hand a good treatise which contains descriptions of the
most minute detail. In such monographs the literature of the
subject is comparatively poor. Detailed descriptions, although not
so thorough as to permit of working from them alone, are to be
found, for French cheeses, in Pouriau's excellent work, and for
American cheeses, in L. B. Arnold's work, on this subject. An
intelligent description of cheese manufacture will be also found in
Dr. Von Klenze's Handbuch der Kdserlitechnik. Finally, descrip-
tions of cheese manufacture are to be found in B. Martiny's book,
and in the author's work on the subject.

In the following epitome, the two chief groups of cheeses are
rennet cheeses and sour-milk cheeses. The rennet cheeses the
author divides into cow, sheep, and goat milk cheeses, &c., and the
cheeses of the larger portion of this class, viz. the cheeses made
from cows'-milk, are further divided into soft and hard cheeses. In
the different paragraphs are given the names of the cheeses and the
countries where they were originally manufactured, arranged in
alphabetical order. Cheeses are designated as fat when they are
made of whole milk, half fat when they are made from half whole-
milk and half skim-milk, and skim when they are made from skim-
milk. No hard and fast division can be drawn between soft and
hard cheeses; but as is necessary from the classifiation adopted, in
the cases in which it is doubtful whether the chesses should be brought
under the one class or the other, the author classifies as soft cheeses
those which have a more or less smeary and soft substance, and as
hard cheeses those which are friable and dry.

As cows'-milk sometimes contains almost as much, sometimes
somewhat more, and sometimes somewhat less fat than nitrogenous
matter, the ratio between fat and nitrogenous matter does not vary
much in fresh fat cheeses — between that of 50 to 50 (taking 100 as
imity). If this varies to such an extent that 60 to 40 is the ratio,
the milk which has been made into cheese has had cream added to
it, and the cheese is a super-fatty cheese. In half-fat cheeses the

246 SCIENCE AND PRACTICE OF DAIRYING.

ratio approximates to 33 to 67, and in skini-milk cheeses, according
to iny investigations, may be from 12 to 88.

120. Rennet Cheese of a Soft and more or less Oily Character,
made from Cows'-milk — Soft Cheeses. — In the preparation of soft
cheeses, the milk is set at comparatively low temperatures, and the
coagulation period lasts for a comparatively long time. Success
depends essentially on the fact of effecting the most thorough
possible separation of the whey and the curd. Soft cheeses are not
subjected to strong pressure. After the coagulation and cutting up
of the curd has been done, it is placed in tlie moulds and allowed to
drip, and finally is subjected in the store to treatment, which consists
in salting the cheese, drying it, and supervising its ripening. Indi-
vidual kinds of soft cheeses obtain their peculiar proj)erties only by
development on their surface during the ripening of certain kinds
of micro-organisms. The ripening of all soft cheeses resembles
essentially a slow process of decomposition, taking place from out-
side inwards. Most kinds of soft cheeses are allowed to ripen
before use, only a few kinds being used in their perfectly fresh con-
dition. Among the soft cheeses are the finest and most highly-
prized table cheeses.

(a) Cheeses which are used in a fresh condition: —

1. Belgian. — Maquee or Fromage Mou.

2. England. — Cream cheese.

3. France. — Fromage de pure creme; Fromage a la creme;
Fromage double creme dit Suisse; Bondon, Bondon de Rouen or
Fromage double creme, dit Bondon; MalakofF; Petit Carres; Anciens
Imperiaux; Gervais and Chevalier; Coulommiers; Fresh Neufchatel
cheese; Fromage maigre, de Ferme mous, a la pie; Fromage blancs.

4. Italy. — Mascarponi, Giuncate, Mozarinelli.

5. A iLstro- Hungary. — Gloire des Montagues and Lady cheese.

(b) Cheeses which are allowed to ripen before being used: —

1. Belgium. — Limburg cheese, Remoudou cheese.

2. Germany. — Algauer, Remoudou, Moriner and Brioler, Miinster
or Box cheese, Strasburg, Hohenheim.

3. England. — Wiltshire, Cream, Slipcote.

4. France. — Brie cheese, Coulommiers, Olivet, Ervy, Troyes,
Chaource, Barbery, Langres, Spoisse, Soumaintrain, Mont d'Or,
Senecterre, Auvergne, Gerome, Bacherins, Fromage de foin, Camem-
bert. Livarot, Macquelines, Thury en Balois, Mignot, Neufchatel,

NEUFCHATEL CHEESE. 247

Bondon de Rouen, Gournay, MalakofF, Pont I'Eveque, Anciens
Imperiaux, Carres affines, Boid Billiers, Tuiles de Flandre, Larrons,
Dauphins.

5. Italy. — Stracchino fresco, Stracchino de Milano, Stracchino
quadro, Gorgonzola, Calvenzano, Robbiole, Robbiollini, Formagelle.

6. Austro-Hungary. — Swarzenberger Mariahofer, Tanzenberg,
Grottenhofer, Hagenberg castle, Steierich, Josephine, Trappisten.

7. Switzerland. — Bellelay, Tetes de moins, Bacherins.

8. Chili. — Chili Soft cheese.

The Preparation of Neufchatel Cheese. — Neufchatel cheeses (Bondons or
Bondes) are highly-prized tahle cheeses. They are of small size and
cylindrical shape, and weigh •12 to "IS kilo. They are chiefly made in the
department of the Seine-Inferieur. Their diameter is 5 cms. and their
depth 8 cms. Two kinds are distinguished, fat cheese, a tout bien, and
skim-milk cheese. The fat cheeses are prepared as follows: — The warm
milk is strained into stone jars, in a room having a temperature of 15° C.
It is treated with rennet, and the jars are placed in Avooden boxes and are
covered Avith a woollen cover. After twenty-four hours the curd is tm-ned
in another room into a basket made of willows, and is covered ovei with a fine
cloth. It is then allowed to drip for twelve hours over a trough. The
curd is then transferred in a cloth to a vessel with holes in its sides, is
covered over with a wooden cover and Aveighted doAvn Avith Aveights.
When it has thus been pressed for tAvelve hours, the curd is transferred
to another cloth and thoroughly Avorked. If the mass be not sufficiently
soft, fresh curd Avhich has not been alloAved to drain is added to it. It is
then filled into moulds of cylindrical form, 5*5 cms. high and 6 to 7 cms.
broad, made out of tin. It is then firmly pressed Avith a stamp, and smoothly
cut above and beloAv Avith a Avooden spatula. The little cheese is then
removed from the mould. After the cheese has been spread on all sides
Avith salt — about 500 grams are used for 100 cheeses, — the cheese is laid
on boards over a trough to drain. When draining has proceeded for
twenty -four hours, it is brought into the ripening-room on a board on which
fresh straAv is placed. Here it remains from fourteen days to three Aveeks
without being disturbed, except by being frequently turned. If the cheeses
become covered M-ith a bluish-green mould, they are placed on fresh straAv
in a special diA'ision of the ripening-room sufficiently Avidely apart, and
pressed and turned from time to time until they shoAv on their surface
flecks of moulds, Avhich, as a rule, is the case after three Aveeks. The
cheeses, Avheji they have attained this condition, are ready for sale, but
they only reach their highest perfection fourteen days later. The period
of ripening requires on the Avhole from six to eight Aveeks. Thoroughly

248 SCIENCE AND PRACTICE OF DAIRYING.

ripe Neufchatel cheeses can be kept for two months without being much
affected. 100 kilos, of milk give on an average 22-5 kilos, of fresh
cheese.

121. Rennet Cheese of a Firm Character, made from Cows' Milk —
Hard Cheeses. — The hard cheeses gain their condition by coagulat-
ing the milk at higher temperatures, and in a less time than is
the case with soft cheeses. The curd is subsequently warmed by
heating it above the coagulation temperature. This subsequent
warming is generally carried out by warming the entire mass of
the curd in a kettle, with constant stirring. Occasionally, however,
when in a fine condition, the curd has hot whey or hot water poured
over it. It is not necessary to press the moulded curd; never-
theless it is generally done, since, by pressing it, the time required
for the preparation of the cheese is shortened, and the process is
rendered quicker. Hard cheeses, which, as a rule, are made heavier
and larger than soft cheeses, ripen slowly, and are almost all adapted
for keeping, and are thus admirably suited for export, even to
tropical countries. Switzerland, Holland, England, and America
divide between them the preparation of hard cheeses for the world's
market. The simplest arrangements for the manufacture of cheese
exist in Switzerland, in the preparation of the Emmenthaler, and the
most inconvenient in America, in the preparation of the Cheddar
cheese. In the preparation of hard cheese, the three different
methods of salting are brought into operation. The steeping of the
cheese in a solution of salt is chiefly practised in Holland, and
salting, by strewing the salt or rubbing it into the cheese in a dry
condition, is exclusively in use in Switzerland. In the preparation
of a few kinds of hard cheese there is developed an abundant growth
of certain kinds of fungi, which in time permeate the entire cheese
mass.

1. America. — Cheddar.

2. Denmark. — Export, Gisler cheese.

3. Germany. — Algauer Hound, Leather, Tilsiter, Ragniter, El-
binger.

4. England. — Cheshire, Gloucester, Leicester, Dunlop, Cheddar,
Derby, Factory, Savoury cheese, Pineapple, Roll, Stilton, Wensley-
dale.

5. France. — Ger, Septmoncel, Gerome, Port du Salut, Gautrais,
Providence, Rangiport, Bergues, Tantal.

PREPARATION OF CHEDDAR CHEESES IN AMERICA. 249

6. Holland. — Edam, Kommission, Manbollen, Gouda, Friesische,
Nemnilch, Neu Juden, Holland Skim-milk cheese

7. Italy. — Parmesan, Cacio cavallo, Chiavari.

8. Sweden. — Farlosa, Flishult, Riseberga, Swartz, Stockhumla.

9. Austria- Hungary. — Battlematt, Borarlberger, Llineburger,
Glissinger.

10. Siuitzerland. — Emmenthaler, Gruyere, Spalen, Battlematt,
Saanen, Wallis, Urfer, Engadine, Appenzeller, Prattigauer Pressen,
Schweizer Mager, Pfister Mager, Chaschol de Chaschosia, Rhein-
waldthaler.

Preparation of Cheddar Cheeses in America. — The manufacture of hard
cheeses, which has developed in America from the beginning of 1860 up to
the present time to an astonishing extent, is carried on according to a method
which is similar in its essential characteristics to the method employed in
England for the manufacture of Cheddar cheese. The American method
only differs in a few points from the English one. The American Cheddar
cheeses are manufactured in the large and numerous cheese factories of the
United States and Canada. They are of cylindrical shape, their shape
generally being such that their diameter is in the ratio of three to two
approximately to their height. They vary in size. Whole milk for the
most part is used in their manufacture. The Cheddar cheeses destined for
export to tropical countries weigh on an average only 14 to 18 kilos. On
the other hand, cheeses destined for export to Europe and for home con-
sumpt are comparatively heavy cheeses, weighing as much as 60 or more
kilos. Cheeses which on an average weigh 27 kilos., measure 35 to 40 cm.
in diameter and 25 to 28 cm. in depth.

If it be desired to mix the evening's milk with the morning milk of the
next day, as is often the case, it is placed in a cool bath, and is kept in
continuous motion by a peculiar arrangement of tubes, through which
water is constantly flowing so as to prevent creaming.

In the preparation of Cheddar cheese in America, special stress is put
on the aeration of the milk after milking. A prevalent opinion is that fine
cheese cannot be made from milk which has not been aerated. For aerating
milk special arrangements are made. That excellent cheese can always be
niade from milk w^hich has not been aerated is, however, well known. The
opinion is also widely prevalent in America that fine cheeses of good
keeping quality cannot be prepared from milk Avhich has been reduced
to a low temperature. On this account great care is taken not to cool the
milk for the manufacture of cheese to too low a temperature, if possible
not below 17° C.

The method of preparation is essentially as follows: — The evening

250 SCIENCE AND PRACTICE OF DAIRYING.

and morning milk is collected, and is poured into the cheese-vat. In cases
where the milk, owing to the fact that the evening milk has been cooled
below 17° C, appears to be still too sweet for perfect coagulation, from
•75 to 2 per cent of sour whey is added, and the milk is warmed to from
28° to 31° C, a small quantity of annatto being added and mixed into it.
In about 20 minutes' time it becomes thick. The curd is then cut with
American knives, and as soon as it begins to sink under the whey, it is
warmed to from 37° to 39° C, and occasionally even 40° to 41° C, being at
the same time stirred. As soon as the curd is reduced to pieces about the
size of peas, it is allowed to stand either in a covered cheese-vat for from
1 to 1 1 or even for 4 hours long imder the Avhey, with occasional stirring,
or the whey is removed and the curd cut into square pieces, and the pieces
laid for a time the one on the top of the other. In every case the curd,
before being taken out of the cheese-vat, must be examined to see that it
has attained the proper degree of ripeness. This is ascertained with the hot
iron. The stronger the degree of sourness in the milk before coagulation,
and the quicker the curd is brought up to the prescribed temperature in
the subsequent warming, the shorter will be the time required for the curd
to ripen. If ripening has taken place under the whey, the use of the curd-
mill is often dispensed with, otherwise the curd is always ground in the
curd-mill. After salt has been added to the ripe curd in the proportion of
from 1-75 per cent to 2 per cent, and in the proportion of '33 per cent to
the milk originally used, the cheese is brought into a tin cheese-mould,
placed under the cheese-press, and covered over Avith a cloth, care being
taken that the temperature is not lower than 15° C. At first the pressure
applied is slight, but it is gradually increased more and more. It is calcu-
lated that the pressure on 1 kilo, of cheese would amount at most to from
7 to 9 Idlos. After two to three hours the cheese is taken out of the press,
the edges are cut, and it is sewn up in broad stripes of white cotton, the
edges of which overlap the edges of both ends of the cheese by 2*5 to 5 cm.,
and they are then firmly stitched on both sides with thread. The cheeses
are then bi'ought into the press again, and allowed to remain till the fol-
lowing day. They are subsequently brought from the press into the store,
and after their covering is taken oflf they are rubbed with hot melted butter,
in which annatto has been dissolved. The next day they are marked with
a number and a statement of their Aveight, and, according to necessity, for
a month or even longer thej^ are frequently brushed and oiled. In order to
ripen a cheese in from 1 to 1|^ months, the temperature of the store must be
kept at 24° C. At a lower temperature ( 1 8° C. ) cheese is ripened more slowly,
but it is better. According to Curtis, the Cheddar cheeses were formerly
kept too dry Noav even a slight growth of fungus on their surface is
permitted. As suitable temperatures for the ripening of heavy cheeses,

PREPARATION OF CHEDDAR CHEESES IN AMERICA. 251

18° to 20° C. may be mentioned; for cheeses of average weight, prepared
from weak rennet, 21° to 24° C; and for skim-milk cheeses prepared from
strong rennet 24° to 27° C. 100 kilos, of milk Avill yield from 9 to 10
kilos, of fresh fatty Cheddar cheese.

Fatty American Cheddar cheeses should possess a uniform firm appear-
ance. They should, however, be capable of being bent, and should possess
a fine pure flavour and a good cheese smell. The cheese will be of an
open character, that is, possessing holes, if the temperature of the air in
the ripening-room be too high and the ripening process be allowed to go
on too quickly.

According to the investigations of Arnold, the general opinion at
present prevalent in America is that Cheddar cheeses will ripen more
quickly the more rennet is added to the milk to thicken it, but that where
little rennet is used cheeses of a better keeping quality are obtained.
The souring to Avhich the curd is submitted to in the cheese-vat is said to
retain the animal smell of the milk, and to overcome the disadvantages
which possibly arise from a long keeping of the milk before making it
into cheese, and to considerably hasten the ripening process. If the
milk manifest any fault, as, for example, if it possess a strange flavour
and smell, or if the animal smell become strongly pronounced, or if the
milk coagulate Avithout having been previously strongly soured before
thickening, the only method of obtaining good cheese in such a case is by
quickly separating the whey from the curd, and by warming it to about
38° C, or by allowing the curd to remain under the Avhey until strong
souring sets in. In this case it is recommended that strong malt vinegar
be mixed with the Avhey in the proportion of 1 to 1000. In order to
obtain good cheese from milk which has been already comparatively
strongly soured, the milk should be thickened at a somewhat low tempera-
ture, namely at 25° to 27° C. More rennet should be added, so that the
rennet action predominates, the curd should be cut as quickly as possible,
and the subsequent warming only carried on to from 27° to 33° C. When
great haste is desirable, this should be eifected by the addition of a quantity
of hot water. In the preparation of winter or fodder cheese, in order to hasten
the ripening where the temperature is low, but where a large quantity of
rennet has been added for thickening purposes, the curd should be kept
for a longer period in the cheese-vat, and a uniform temperature of 24°
to 27° C. should be maintained in the ripening-room.

Lately much cheese has been made in America by the American
Cheddar process from milk more or less creamed, or from skim-milk, the
result being that the reputation of the American cheese manufacture has
been considerably lowered. In the manufacture of such cheeses, it is to be
recommended, in order to assist the action of the rennet, and to hasten

252 SCIENCE AND PRACTICE OF DAIRYING.

ripening, to coagulate butter milk along -with the creamed milk, and to
coagulate at a temperature of 26° to 27^ C. More rennet than is used in
the manufacture of fatty cheeses should he added, in order to reduce the
curd to a finer state, and subsequently it should be submitted to a more
moderate warming. Skim-milk cheese should also receive more salt than
fat cheese, and should be alloAved to ripen at a temperature of at least
24° C. Elsworth recommends a special method of treatment of Cheddar
and skim-milk cheeses. The milk is heated to from 57° to 58° C, and
is then cooled to 15° or 16° C, poured into the cream vessel, and after
the lapse of thirty-six to forty hours it is creamed. The cream is churned
in a sweet condition, a portion of sweet butter-milk is added to the skim-
milk, and the Avhole is treated as in the preparation of fatty cheeses. By
the previous warming, as well as the addition of butter-milk, the ripen-
ing of cheese is said to be hastened.

The proper so-called "ripeness" of the curd is said to exert an influence
on the cheese. If the curd be made into cheese when it is not sufficiently
sour, the result is, it is asserted, that a soft cheese is obtained, which is
liable to rapid decomposition, and which, it is true, quickly becomes market-
able, but never gains a fine flavour such as cheese has, the curd of which
has been kept for a long time in the cheese-vat, and has been subjected to
souring in the proper manner. A dry cruml>ling cheese is obtained from
cheese which has been too strongly soured.

The Preparation of Cheddar Cheese in England. — This cheese is made
extensively in the western counties of England, where the art of cheese-
making was already considerably developed at the beginning of this
century. It is made from a mixture of morning's and evening's milk. The
cheeses are cylindrical in shape, 27 kilos, in weight, on an average, and
are about 27 cms. deep, with a diameter of 36 cms. The heaviest cheeses
weigh up to 50 kilos., while the lightest only weigh from 8 to 10 kilos.

The preparation is carried on as follows: — The milk is first coloured
with annatto, and often indeed with the juice of carrots or marigolds.
It is allowed to thicken, at from 27° to 32° C, in from 60 to 75 minutes.
The curd is then broken up with the ordinary cheese-knives. The milk is
previously Avarmed in round cheese-vats, made of oak, by adding a portion
of strongly -heated milk to the rest of the unwarmed milk, or by the
addition of hot water to the milk. In the prepaiation of cheeses of 27
kilos, in weight, the cutting up of the curd occupies about 20 to 25
minutes. Before the sepaiate pieces of the curd are reduced to the proper
size, they are left for fifteen minutes in the covered cheese-vat, a portion
of the whey is then removed, and the work of breaking up the curd is
finished. After this the whey is all removed, Avith the exception of a very
small quantity, and the curd is drawn together and covered over with

THE PREPARATION OF EDAM CHEESE IN HOLLAND. 253

perforated boards which are -weighted with 15 kilos. AVheii it is observed
that no more of the whey is driven out in this way, it is removed, and the
board is weighted with 30 kilos. The mass of curd after a short time i.s
broken up, either \\dth the hand or with the cuixl-mill, and then submitted
for some time to a pressure of from 50 to 60 kilos., 2*5 to 3 per cent of
salt being then worked into it. The curd-mass is finally sewn up in cloth,
and is placed in a round chest of wood or tin, with perforated sides, and
put under the press. Long iron or wooden pegs are stuck through the
holes of the mould, in order to facilitate the removal of the whey during
pressure. After a short time the cheese is removed from the mould, is
broken up and put into a fresh cloth, and again pressed for a short time.
This treatment is repeated several times, till finally the cheese is allowed
to remain in the press, under great pressure, for several days. In the
meantime it is turned repeatedly, and care is taken that the whey flows
from the mould. The pressure is increased to such an extent that it
finally amounts to 30 kilos, per kilo, of cheese. After the pressure has
been finished, the cheese is taken out of the mould, divested of its
cheese-cloth, brought into the store, and treated in such a ^yay that a
hard rind is imparted to it. This is done by allowing it to remain for
several days in a brine solution, or by rubbing salt into it. The cheeses
which have salt rubbed into them, especially if they be very fat, are sewed
up in linen, so that their shape may not be lost. As soon as the rind has
been made sufficiently firm by the action of the salt, the cheese is dipped
for a moment in warm water or warm whey. It is then dried and put in
the ripening-room, where it is turned daily until it has become perfectly
dry. When it has become dry, it is turned in summer three times and in
winter twice a week. From time to time it is rubbed with butter. At an
average temperature (15° C.) Cheddar cheese ripens so as to be ready for
sale in from three to four months. Cheese of an average size of 27 kilos, do
not attain their highest perfection till from six to ten months have elapsed.
Large cheeses require nearly two years before they are ripened. In the
store the Cheddar cheese loses in the course of a year about 15 per cent
of its weight. Those cheeses which are most highly prized, and which
are exported in quantity, possess a firm wax-like appearance, but arc at
the same time porous. When ripe in the inside, as well as near the rind,
a small bright green development of mould may be observed. Cheddar
cheese are imitated, especially in Holland and America, as well as in
Sweden. 100 kilos, of milk yield on an average 9 to 11 kilos, of fresh
fatty Cheddar cheese.

The Preparation of Edam Cheese in Holland. — The Edam cheeses (cats'
heads, fetes de maure in France) are chieHy made in North Holland, and arc
placed on the market in large quantities from the town of Edam, which

254 SCIENCE AND PRACTICE OF DAIRYING.

lies 19 kilometres N.E. of Amsterdam. They are fat round cheeses, and
Aveigh usually 2 to 4 kilos., and have a diameter of 11 to 15 cms. The
cheeses are very seldom made larger or heavier. The heaviest cheeses weigh
about 12 kilos, each. Those prepared in the neighbourhood of Hoorn are
considered the finest. Those which are prepared in the neighbourhood of
Beemster Alkmaar are also highly prized, and are only very slightly in-
ferior to the cheeses which come from Edam. The small so-called "prasent"
cheeses are the finest quality prepared. The smaller cheeses are divided
into May cheese, 2 to 5 kilos., Summer cheese, 1*5 to 2 kilos., and Autumn
cheese, 2 kilos. The Edam cheeses form a very important article of export
from Holland, and find their Avay as far as tropical countries, like China
and Australia. They keep for several years. As a rule, those destined
for export are coloured externally a glittering red; occasionally also
yellow, and sometimes partially red and blue in alternate segments.

The milk is placed in a wooden vessel, at 32° to 34° C. in summer, and
in Avinter at 34° to 36° C, and thickened in eight to fifteen minutes.
Along Avith the milk a small quantity of annatto colouring matter is put
in. The curd is very carefully broken, so that no loss can take place in
the fat. The breaking of the curd ought to occupy from four to seven
minutes' time. (This statement, as Avell as those following, is based on the
assumption that from 100 to 150 kilos, of milk are being treated.) After
the breaking the curd is left for tAvo or three minutes, is drawn together
from the bottom of the A^at by means of a Avooden boAvl with holloAved
surface, the bulk of the Avhey is removed, and is pressed into the vat four
times in such a Avay that the boAvl rests on the curd with a Aveight of
10 to 20 kilos. After pressure has been continued for four or five
minutes, the Avhey Avhich fioAvs out is removed. When this operation, Avhich
should last, on the whole, from fifteen to sixteen minutes, is finished, the
temperature of the curd should be in Avinter at the lowest 28° C, and in
summer at the highest 32° C. If the curd has not the proper temperature,
that should be imparted to it by pouring over it Avhey or Avater of a suit-
able temperature. The curd, Avhen brought to the proper temperature, is
removed from the cheese-vat into Avooden moulds, strongly pressed AAath
the hand, and turned tAvo or three times. Care should be taken that the
holes for permitting the outfloAv of the Avhey are not choked up. In order
to prevent the cheese mass cooling too quickly during moulding, this
operation should not occupy at the most more than four or five minutes
time. In summer the precaution should be taken, in filling the mould, of
adding a small quantity of salt in the middle of the cheese, or treating the
curd, before it is put into the moulds, Avith a little salt water. As soon as
the cheese has become sufficiently firmly pressed, it is removed from
the mould, and kept for one or two minutes in a bath of Avhey, Avhich

THE PREPARATION OF EDAM CHEESE IN HOLLAND. 255

in summer is kept at 52" C, and in %vinter at 55'' C. The cheese is then
removed back from this vat into the mould. It is again pressed for t"\vo
minutes more with the hands, remo^■ed from the mould, wrapped up in a
piece of linen, and put back into the mould, Avhich is then covered with its
cover and placed in the press, where it is kept for a period varying accord-
ing to the time of year, and to the keeping qualities which it is desired to
impart to the cheese. Ordinary cheese is pressed in winter for one or
two hours only, in summer, on the other hand, for six or seven hours, and
cheese destined for export is pressed for twelve houi's. When the cheese
has been removed both from the mould and the press, it is placed, after
being divested of the linen around it, in another shallower wooden mould,
which is so arranged that the cheese is rounded more on the one side than
on the other, and, on the other hand, is also held firmly, so that it may
not roll. In these latter moulds the cheeses are placed beside each other in
a comparatively deep square wooden box provided with a lid, the floor of
Avhich is slightly rounded, and provided at its deepest place Avith a hole for
the outlet of the whey and the brine, and on the first day, above each
cheese, a little salt is spread. On the second day the cheese is dipped in
damp salt, so that the whole surface of the cheese is covered -with salt. It
is then returned to the mould, where it is placed in such a way that the
portion which was first uppermost is now undermost. In this Avay salting
is continued for nine or ten days, until the cheese is completely saturated
Avith salt, and is no longer elastic, but quite hard to the touch. Finally,
the cheese is laid for some hours in the brine which has been collected,
Avashed Avith Avater, dried, and placed on a wooden stand in a dry, Avell-
aired store-room, in Avhich the temperature of the air is not alloAved to fall
beloAv 6° C, and not to rise aboA^e 22° C. In many cheese factories the
cumbersome method, above described, is dispensed Avith, and the cheese
is placed directly in strong brine. The airing of the store-room should
be supervised Avith the greatest care, and must be discontinued in very
dry as Avell as in foggy or damp AA^eather. If the store-room be too damp,
the cheese becomes coA^ered over AA'ith a blue or yelloAvish mould, and
depreciates in quality. During the first month the cheese is turned daily,
and during the second tAvice a day, and subsequently only tAA'ice a Aveek.
As soon as the cheese is a month old it again undergoes special treatment.
It is softened for an hour in water Avarmed to 20° to 25° C, then brushed
Avith a brush, dried for from tAventy to forty minutes in the sun, and
returned to the store-room. After the lapse of fourteen days this treat-
ment is repeated, and the cheese is rubbed with linseed oil. It is common
in Holland to sell cheeses only six Aveeks old to the dealers, Avho themselves
submit the cheese to the subsequent treatment. Cheeses destined for
export are scraped Avith a sharp knife or special machine before being sent

256 SCIENCE AND PRACTICE OF DAIRYING.

away, so that they may have as smooth a surface as possible. They are
then coloured according to their destination. Cheeses Avhich are not des-
tined to be sent far, are either not coloured at all, when they are put on
the market as white cheese, or they are coloured Axith colcothar. Cheeses
destined for export are usually coloured Avith a substance which consists
of 36 per cent of tnrnesol {Crozojjhora Undoria), 3 per cent of Berlin
red, and 61 per cent of water. 16-5 kilos, of this mixture, costing about
nine to ten marks, is sufficient to colour 1000 cheeses. The cheese is
painted Avith this mixture, alloAved to become dry, and then rubbed off
Avith a little butter, Avhich is slightly coloured with Berlin red. The
cheeses are finally packed in boxes side by side, separated by small boards,
or wrapped up in animal bladders. The cheeses Avith red rinds are knoAAm
as red-crusts. Simpler but less appetizing is the practice of colouring the
cheese red Avith Avoven cloth coloured red Avith the juice of turnesol. The
cheeses destined for England and Spain are coloured yelloA\^, the colour
being imparted by a solution of annatto in linseed-oil.

From 100 kilos, of milk 10 to 11 kilos, of fresh and 8 to 9 kilos, of
saleable Edam cheese is obtained. Whey butter is j)repared from the
Avhey.

Good Edam cheese becomes coA^ered over in time AA'ith a thin dry bluish
green efflorescence. In addition to the fact that the cheese becomes puffy
or oily and cracked, it is often flecked Avith blue patches. A curious fault
of this cheese consists in the fact that, eA'en where the rind is perfectly
sound, internal fissures are to be found in the inside of the cheese, so
sharply cut that they look as if the}' had been cut AAath a knife. In
cheese Avhere this is the case, either in course of time putrefactive decom-
position takes place, or the rind sinks over the fissure and forms homes
for the gi'OAvth of moulds. Too damp an atmosphere, and, still more, dry
cold Avinds, are hurtful to the cheeses in the store. In the preparation
of Edam cheese, it is not considered advisable to use the milk of newly-
calved cows before the ninth day. Milk A^ery rich in fat is not so suitable
for the preparation of Edam cheese. Edam cheese Avhich has gone bad
is pounded into barrels, and the mass is sold as pottkaas.

The Preparation of Enunenthaler Cheese in Switzerland. — Emm en-
thaler cheese, the best and most famous of SavIss cheeses, is chiefly manufac-
tured in the Canton of Berne. The Emmenthaler cheeses are made from
whole milk, or a mixture of Avhole milk and slightly skimmed milk, and
are exported to all parts of the Avorld, especially to Germany, Austria,
Russia, France, and North America. In North Germany they are knoAvn
as "thranen" cheeses, and in France they are knoAvn under the name that
is applied to all SavIss fatty hard cheeses, namely Gruyere. They possess
the shape of mill-stones, and Aveigh nearly 50 to 65 kg., Avith a diameter

THE PREPARATION OF EMMENTHALER CHEESE. 257

of 70 to 80 cm., and a height of 10 to 13 cm. In certain districts cheeses
even heavier and larger are made, possessing a Aveight of 100 to 125 kg.
or even more. In the author's opinion, the Emmenthaler is the finest and
the best of all the rennet cheeses, and requires for its preparation more
knowledge in the art of cheese-making, and more skill and practice, than
does the preparation of any other kind of cheese.

In the preparation of fat cheeses, the morning's milk is warmed in copper
kettles to -40' to 42° C. The evening's milk of the previous day is creamed
in the meantime, and the cream added to the warm morning milk, and
thoroughly mixed therewith, which is easily effected owing to its tempera-
ture. The cooled evening milk, which has been thus skimmed, is then
added to it, thoroughly mixed with it, and the temperature of the liquid,
according to the time of the year and other conditions, raised to 33° to
35° C. It is then coagulated in 20 to 35 minutes. During the thickening,
the cheese-kettle is covered if necessary. Along with the rennet is added
a small portion of cheese saffi'on, which is mixed previously with a small
quantity of milk. It is better to add an exactly measured quantit}- of
saffron solution proportional to the quantity of milk to be coloured.
As soon as the curd has obtained the proper firmness, it is cut with
the cheese-knife crosswise into pieces of a parallelepiped shape, and the
whole mass is turned in the kettle with the scoop, so that the lowermost
portions are brought to the surface. It is cut at the same time into
pieces about the size of one's hand, and stirred with stirring-sticks until
they are the size of peas. This operation occupies about 25 minutes.
The curd is then allowed to stand for a moment, and 25 per cent of the
whey is removed into a tub prepared for the purpose. It is then again
stirred and the warming continued. The temperature during this continued
stirring is gradually raised to 56° to 58° C, and the stirring is still
continued, until the curd, which is frequently tested, has gained the desired
firmness and elasticity. As warming and stirring occupy 35 minutes, the
entire treatment of the curd in the kettle takes on the whole about 60
minutes. After the stirring has been finished, a portion of the hot whey
is removed into a special vessel, and poured into the kettle among the
whey which has been previously removed, in order to lower the tempera-
ture of the contents of the kettle, so that when the curd is removed the
arms may not be burnt. The entire mass of curd is then lifted by means
of a wooden hook and a cheese-cloth, and placed in the mould -hoop
between box covers under the press. Here the cheese remains for 24
hours, and during this time it is turned in all 7 or 8 times, for the first
time after some 15 minutes from the time the cheese has entered the press,
and 30 minutes later, and again after an hour, and from then on at intervals
of rapidly increasing length. At every turning the cheese-cloth is removed,

(M175) K

258 SCIENCE AND PRACTICE OF DAIRYING.

and the mould-hoop if necessary is made narrower. If, owing to the
pressure, small protuberances of cheese are formed on the top and bottom
of the hoop, these should be cut off with a short knife at the third turning.
At first the cheese is submitted to a weak pressure, which is gradually-
increased, and which after 8 hours is rapidly increased, viz. 8 to 10 kg. for
a cheese of 30 kg., and 14 to 16 for a cheese of 50 kg. on every kilogram of
cheese. For pressing cheese the Swiss lever presses are used. After the
whey which has been drained off has been put back into the kettle, the
next process is to separate the whey cream. The temperature is slowly
raised at first until it has reached 68° to 70° C. One part of strongly-soured
whey is then added for every 100 parts of milk to be treated. The tem-
perature is then increased to from 80° to 95° C, and the froth, which in
the meantime is separated from the clear whey, is skimmed off. The
quantity of whey cream amounts on an average to from 3 to 4 '5 per cent
of the milk treated. After standing for 24 hours and churning in the ordi-
nary method, "75 kg. of whey cream butter should be obtained for every
100 kg. of milk. As soon as the whey cream has been skimmed off, one
to three — on an average two parts — of sour whey is added to 100 parts
of the milk to be treated, and the whole is slowly warmed until the whey
at the bottom of the kettle begins to boil, and the Ziger, known also as
Bavarian Algau {i.e. the albuminoid matter remaining in the whey), comes
to the surface, and is separated out in the form of large porous pieces of
a yellowish colour. Occasionally it happens that the ziger does not come to
the surface. In such a case the manufacturer effects this by jDlacing a
wooden milk-bowl on the whey, and allowing it to float. Thereupon
the liquid immediately below the bowl sinks, since it is rapidly cooled,
and causes currents to take place in the milk which bring the ziger to the
top. After the ziger has been scooped off by means of a perforated tin
ladle, the entire milk utensils, including the churn, are cleaned with the
whey remaining behind. For every 100 kg. of milk treated, there is
obtained, on an average, from 7 to 8 kg. of fi-esh ziger. If, on the other
hand, the ziger is weighed only after it has been made into cheese, and
submitted to strong pressure for 24 hours, it will be found that only 2 to
3 kg. of fresh ziger cheese is obtained for 100 kg. of milk treated. Ziger
cheese is only made to a small extent. Since fresh ziger, when eaten along
with salt and potatoes, furnishes a pleasant and nourishing food, it is in
some parts regularly used as an article of diet. It is chiefly used, however,
along with whey, for feeding calves, especially bull calves, and pigs. When
pigs are fed with ziger and whey, it has often been noticed that where they
receive no other food except butter-milk a breeding sow may be fed on the
milk of 4 to 6 cows. In some parts of the Alps the experiment has been
made of utilizing whey as a manure, just in the same way as urine is used.

THE PREPARATION OF EMMEN THALER CHEESE. 259

This method of utilizing whey, however, is not to be commended. In the
cantons of Berne and Lucerne in the Alps, the so-called sugar-sand is
obtained in summer from the raw milk-sugar of the Avhey. Occasionally
— that is about once or twice during the period of mountain pasturing — ■
the cow-keepers boil the whey and prepare molkenslch, a substance made
out of the solid constituents of the whey. It consists mostly of sugar,
is of a chocolate-brown colour, and is shaped in the form of a brick. It
is used for eating with bread-and-butter on festive occasions.

The soured Avhey, the sourer which is used to separate out the whey
cream and the ziger, is put in the sourer barrel, which is placed in a warm
part of the cheese-store, usually near the fireplace of the cheese-kettle. It
is made of wood and of a conical shape, and of from 75 to 100 litres
capacity. This baiTel is covered with a wooden lid and fitted underneath
with a cock, and is not allowed to become empty during an entire
period. It is at first filled with whey, which rapidly sours, owing to the
warm place in which the barrel is kept. The whey required is daily
tapped off, and the space filled up again immediately with sweet whey.
The strength of the sourer determines the quantity to be used. If at the
beginning of the period of mountain pasturing no sourer is obtainable,
diluted vinegar is employed.

After the cheese has been taken out of the press, it is mmibered with
ink, or with a black colouring matter prepared from lamp-black and oil,
and is brought into an airy room, where it is allowed to remain for 24
hours, generally as it is, occasionally in a mould-hoop. It is thereafter
brought into the cheese-cellar and treated with dried salt. During the
first weeks the cheese is provided with cheese-binders similar to mould-
hoops, but made of soft wood. The mode of salting, as well as the diff"er-
ent precautions which have to be carried out in salting this cheese, haA'^e
already been pointed out and discussed in § 115, and the requirements
which are necessary for a good cheese-cellar as well as the temperature and
moisture most suitable for the storing of cheese, have already been discussed
in § 116. About 20 days after the cheese has been brought into the
cellar, often indeed sooner — sometimes as soon as it has been brought under
the press — the formation of the large eyes in the cheese begins to take
place. Before cheeses of 50 kg. and above that weight have become per-
fectly ripe, and have attained their full taste, 8 to 12 months must at least
elapse, during which time the cheeses on an average lose about 12 per
cent of their weight. For salting, on an average, during the first two
months, 2 kg. of salt are required per 100 kg. of cheese, and the loss in
weight in this time amounts to from 6 to 7 per cent. In the preparation
of fatty cheeses, 100 kg. of milk yield in summer on the Alps 9 to 11 kg.
of Emmenthaler cheese, in summer in the valley dairies, 8 to 10 kg., and

260 SCIENCE AND PRACTICE OF DAIRYING.

ill winter 7 to 9 kg. In the preparation of half fatty cheeses, there is
obtained per 100 kg. of milk on the Alps 9 to 10 kg. of cheese, and in the
valley dairies 8 to 9, and in Avinter 7 to 8 kg. It is calculated that in the
preparation of half fatty cheeses, that is, cheeses made from morning milk
and skimmed evening milk of the previous day, from every 100 kg. of
fresh cheese there are made in summer 14 to 16 kg. of butter, and 13 to
15 in Avinter; and each additional kg. of fat in the cheese increases or
diminishes the weight of the cheese by 1*5 kg.

Good Emmenthaler cheese of the best quality should possess a mild,
piquant, nutty flavour, and should be free from fissures or cracks. On
a fresh-cut surface the ejes, namely, the single large circular openings

which distinguish this cheese from all
other cheeses, should be uniformly placed
in the cheeses, and should appear of a
uniform size. The distance between the
different eyes should be 4 to 6 cms. The
internal portion of the eyes, which varies
from 6 to 10 mms., on an average 8 mms.,
should possess a dull glitter, but should be
free from small drops of liquid. The Em-
menthaler cheeses which have not been suc-
cessfully manufactured are divided, accord-
ing to the more commonly occurring faults,

Fig. 75.— Bacillus iliatrypeticus casei. . n n i , t^ tvt- ? ^ r^i i

Enlarged 850 times. mto breoliihte Kiise, JSiszler, and (jrUlsler.

Our information with regard to these
faults is based upon the observations and opinions of cheese manufacturers.
Scientific opinion and research have only been very recently undertaken
on the subject. According to the practical man, the explanation of the
proper course of ripening, and the explanation of the faults to which the
cheeses are liable, are extremely complicated. This is no doubt true, but
not to the extent which is believed.

So far as our knowledge at present extends, the most of the processes
in operation on the ripening of cheese are caused by fission fungi, and it
is certain that in the peculiar ripening process going on in the Emmen-
thaler cheese, certain gas-generating bacteria, in addition to many other
kinds of bacteria with other properties, exercise an important function.
To these gas-generating bacteria belong the bacillus depicted in the accom-
panying diagram (fig. 77). The lactic bacteria are agents exercising a
secondary influence. The action of the gas-generating bacteria should
neither begin too early nor go on too long for the cheese to attain its proper
condition. It should go on exactly at the time that the cheese mass has
attained a certain amount of firmness and mobility, in an even manner,

RENNET CHEESE FROM SHEEP's MILK. 261

and should not be interrupted. Certain gas-generating bacteria, which are
always present in the byre, in the food, in the udder of the cow, and in
dairies, occasionally in enormous quantities, should not be wanting in
milk which has to be made into cheese, but they should not be permitted
to choke out other kinds of bacteria.

Lately it has been discovered that the preparation of Emmentlialer
cheese is facilitated if the milk which has to be treated possess a certain
definite degree of sourness, neither too strong nor too weak, and that it
is desirable where this sourness is lacking to increase it by the addition
of sour whey. The quantity of lactic ferment which, as experience has
taught, produces the proper degree of sourness, seems to regulate in a bene-
ficial manner the 'growth of the gas-producing bacteria, by limiting them
when they are in excessive quantity, but not exercising an unfavourable
"influence when they are present in small quantity. If the manufacture
of the cheese gains in secui-ity by the addition of small quantities of sour
whey to the milk, it loses on the other hand, it would appear, in fineness of
flavour.

Puffy cheeses have irregularly distributed cavities as large as the fist,
and exhibit a more or less disfigured external appearance, assuming in the
course of time a peculiar soapy flavour. Very often the swelling of the
cheese begins on the surface; and often a few hours after the preparation
of the cheese it becomes puffy, when the ordinary gas-forming bacteria
choke out the other bacteria, or when strange ferments are present Avhich
give rise to a fermentation in which there is a development of gas. This
occurs most frequently where the milk to be treated is dirtily handled,
and feeding-stuffs have been used Avhich contain such fungi. Puffiness
is favoured by faults in the preparation and treatment of cheese, Avhich
result in too much moisture remaining behind in the cheese mass, such
as using too weak rennet, thickening at too low a temperature, insuffi-
cient stirring, too quick warming, careless straining of the curd, insuificient
pressure, carelessness in pressing, unskilful salting, and too high a tempera-
ture in the air of the store-room. Puffiness in the cheese, in the opinion
of the author, is in most cases caused by fission fungi, and not by budding
fungi. The gases produced in pufiiness, in addition to carbonic anhydride,
are large quantities of hydrogen.

122. Rennet Cheese from Sheep's Milk. — Cheese from sheep's
milk is prepared wherever sheep are kept on a large scale. It is
made in small quantities, and for consumption in the neighbourhood
of the place of manufacture. Only one kind of cheese made from
sheep's milk, viz. the famous Roquefort cheese, made in France, is
placed on the world's market.

262 SCIENCE AND PRACTICE OF DAIRYING.

The following is a list of cheeses made from sheep's milk in
different countries : —

1. Germany. — Mecklenburg.

2. France. — Roquefort.

3. Holland. — Tereler.

i. Italy. — Formaggio fresco di pecora detto cacio fiore, For-
maggio dolce di pecora, Formaggio detto da taglia grosso, Formaggio
di pecora merina, Formaggio di pecora da Serbare, Formaggio delle
Crete Senisi, Formaggio di pecora detto cacio fiore di Viterbo, For-
maggio di pecora di Lionessa, Cacio di Puglia, Marzolino, Tratturo,
Formaggio all uso Parmigiano, Formaggio di Catrone, Ancona Skim-
milk, Scanno Skim-milk, Iglesias Skim-milk cheese.

5. Austro-Hungary. — Brinsen, Laudock, Zipser, Liptauer, Sie-
benberg, Neusoler and Altsoler Carj)athian, Kascaval, Kolos
monostor, Klenoczer, Abertamer,

Preparation of Roquefort Cheese in France. — The celebrated Roque-
fort cheeses, which form extremely fine-flavoured table cheeses, are made
from sheep's milk. They are made from a mixture of whole milk and
partially skimmed milk. In form they are cylindrical, and in a fresh con-
dition are 18 cms. in diameter, 8 cms. deep, and on an average 2'15 kilos,
heavy. In the ripened cheese they are 17 cms. in diameter, 7*5 cms. deep,
and on an average 2 kilos, in weight. Good ripened Roquefort cheeses are
neither soft nor oily, but are friable in appearance, and are permeated with
grayish green patches of fungoid growth. The preparation of Roquefort
cheese, which was formerly made from a mixture of sheep's and goats'
milk, is very old — indeed, it is known that it was practised in the caves of
Roquefort as early as the year 1070. The preparation of this cheese was
formerly confined to the neighbourhood of the village of Roquefort, in the
Department of Aveyron, on the river Soubzon; but it has now spread over
the entire arrondissement of St. Affrique and of Milhau, over a portion
of the arrondissement Lodeve (Department Herault), over the cantons of
Canourgue (Department Lozere), and of Treves (Department Gard), as well
as over the single canton of the Department Tarne. Roquefort cheeses
seem to owe their peculiar properties partly to the naturally cool and
continuous currents of air passing through the rock caves in which the
ripening is carried on. These caves are situated in the narrow, flat moun-
tain passes which run between St. Aff'rique and St. Rome de Cernon on
the east, and to the north side of the tableland of Larzac, and are chiefly
cut out of the Jurassic chalk.

The milk used for the preparation of Roquefort cheeses is obtained
from Larzac sheep, which are milked twice a day. The evening milk

PREPARATION OF ROQUEFORT CHEESE IN FRANCE. 263

has its frotli first removed, and is allowed to stand for three-quarters
of an hour, when it is heated in a galvanized copper vessel almost to
boiling, cooled down, and kept overnight in glazed clay boAvls. On the
following morning the cream is removed in order to be subsequently
churned, and the morning milk is added to the skim-milk, and thickened
at 33° to 35° C. with rennet. The curd is carefully broken up and the whey
removed. Each piece of the curd is pressed carefully in order to remove
as much of the whey as possible, and placed in cylindrical moulds made out
of strongly burnt glazed clay, Avhich are 21 cms. broad and 9 cms. deep,
and in the bottom of which there are round holes '5 to "6 cm. broad. This is
done in such a manner that the curd is placed in the moulds in three
equally thick layers, between every two of which a layer of firmly baked
cake of powdered mouldy bread is placed. This is most suitably made
out of ec|ual parts of wheat and barley -meal, with the addition of sour
paste and strong vinegar. For every 100 parts of paste there should be
4 to 4-5 parts sour paste and '05 parts of vinegar. The fresh baked bread
is alloAved to become mouldy, and the mouldy crumbs, cut off it and
ground in a hand-mill, are pressed through a sieve. In this way, by add-
ing this powder to the curd, the spores of the moulds are conveyed into
it, and under their action the ripening process of the cheese is effected.
Boards are laid upon the raised surface of the curd mass in the mould.
These are at first slightly weighted, subsequently more heavily, and then
pressed from 10 to 12 hours in this Avay, the cheese being repeatedly
turned. After the pressing operation has been finished, the cheese is
removed from the mould, and alloAved to lie for 10 to 12 days wrapped
up in cloth. They are turned twice a day, the cloth being often renewed,
and finalh', after the cloth has been taken off, drying is promoted by a
dry current of air. The cheeses are then brought carefully from the
drying-room during the night-time into the rocky caves, each of which is
divided into three compartments — the so-called grotto (la cave) in which
the cheese is allowed to ripen, the salting-room (le saloire), and the weigh-
ing-room Qe 2)oids). The two last mentioned rooms are situated above
the grotto. After the damaged cheeses have been separated out in the
weighing-room, which also serves as a receiving-room, the other cheeses are
laid upon a straw-covered floor. They are allowed to stand for 12 hours,
from morning till evening, and are then broiight into the salting-room.
Here the cheeses are strewn with fine salt on the one side. They are placed
three deep, and turned after 24 hours, when they are salted on the other
side and again piled up as before. After the lapse of 48 hours the salt
is rubbed into the cheese on all sides with a coarse linen cloth, and the
cheeses are then left again, piled three deep, for another three days. At
the end of this time they are brouijht back into the weighing - room,

264 SCIENCE AND rRACTICE OF DAIRYING.

where they are submitted to a somewhat laborious cleansing (le reclage),
i.e. they are scraped twice with sharp knives. The material which is first
scraped off, which is known as '■'■pegot", is used as food for pigs, and what
is subsequently scraped off, and Avhich is known as "ribarbe blanche", is
sold at 32 to 40 pfennig per kilo. After the scraping operation is finished,
it is possible to judge of the individual excellence of the cheeses. They
are separated according to quality into three classes, and are placed three
deep in the grotto, the hardest cheeses being placed on the straw-covered
floor, Avhile the others are placed upon Avooden stands arranged round the
walls and in the middle of the room, and provided with straw. In the
grottoes, into which cold air is constantly passing through numerous clefts,
the temperature of the atmosphere varies throughout the whole year
between 4° and 8° C. The air contains only about 60 per cent of its
average moisture. Eight days after the cheeses have been removed to the
grotto, they are placed on their sides, in order to promote the circulation of
air over their surface. The chee3es are covered during the ripening at
first with a reddish or yellowish crust, on which is developed, subsequently,
a thick white substance. As soon as the covering of mould has reached
a thickness of 5 to 6 cms. the cheeses are again scraped, this scraping {le
revirage) being repeated at intervals of from 8 to 14 days, until the cheeses
become ripe and are removed from the grotto. The scrapings (reveriim)
are used for feeding pigs. During the whole process, from the time the
fresh cheese is brought into the cave, up to the time it is ready for the
market, it loses 28 to 30 per cent in Aveight, and the loss of Aveight due
to repeated scraping in the grotto amounts to 23 to 25 per cent. The
cheeses which are prepared during the early months of the year should
become ripe and ready for sale in 30 to 40 days, and those made later in
a someAA'hat longer period. 100 kilos, of milk yield 18 kilos, of fresh cheese
ready for salting, and 12 to 14| kilos, ready for the market.

The treatment of Eoquefort cheeses in grottoes, Avhich up to 1873
Avas almost exclusively effected in a clumsy Avay by hand-labour, was very
much improved in the year 1874 by the director of the United Cellar
Company, who introduced tAvo special machines driven by steam, which
thus replaced to a certain extent the slow and laborious methods pre-
viously employed. One of these machines was the brushing machine,
Avhich effects the scraping of the cheese, and Avhich can be Avorked by tAvo
Avomen. The cheese are brought at first betAveen two circular-shaped
horizontal brushes, Avhich clean the bottom and the top of the cheese, and
then betAveen vertical brushes, Avhich clean the sides of the cheeses. They
are so constructed that they can clean per hour 4800 cheeses, or as many
as could be undertaken in the same time Avith difficulty by 20 women. At
the same time the machine only causes a loss of 10 per cent, instead of 23

CHEESE FROM GOATS AND OTHER MILK. 265

to 25 per cent. The other machine is the Prickel machine, and can also
be worked by two women. It pierces through, Avith a Avheel provided
with 60 to 100 very fine comparatively long needles, 10 to 12 cheeses
every minute. Although the cheese mass is inoculated with large numbers
of fungoid spores, it is found that the development of moulds in the
interior of the cheese at the temperature prevailing in the grotto is not as
rapid as desirable. As the fungi in the interior of the cheese develop
more rapidly the more air is admitted, this is effected by pricking the
cheese with needles, and an increased development of fungi is obtained.

The cheeses most prized are those made in the grottoes during the
months of May and June, Avhich are ready for sale from September to
December. They are packed in cylindrical baskets, in Avooden baskets,
gagets, and in boxes. BetAveen each cheese thin pieces of Avood are placed.
The finest cheeses are Avrapped up in tin-foil. Roquefort cheeses are ex-
ported to all parts of Europe, to America, to the colonies, and to China.
The finest, and at the same time, those possessing the best keeping
qualities, are called Creme de Roquefort. In the districts surrounding
Roquefort, cheese is made from coAvs'-milk after the Roquefort method.

123. Rennet Cheeses made from Goats', Buffalo, and Reindeer Milk,
and also from Mixed Milk. — The cheeses made from this group are
of little importance, as they are only manufactured in small quantities,
and for immediate use in the neighbourhood of the place of manu-
facture. They are as folloAvs: —

1. Germany. — Ziegenkase des Riesengebirges, Altenburger
Ziegenkase.

2. France. — Mont d'Or, St. Claude, Gratairons, Chevretins, St.
Marcellin, Sassenage, Septmoncel, Mont Cenis, Tignards, Gavots.

3. Italy. — Blissel, Provole, Scarmorze, Borelli.

4. XajsZcMifZ.— Rennthier.

5. Norway. — Hviteost.

6. Aiistro- Hungary. — Brinsen, Arnauten.

7. Siveden. — Ziegen, Rennthier.

8. Switzerland. — Ziegen, von Graubiinden, Gaiskasli von
Solothurn.

124. Sour -milk Cheese made from Cows' Milk. — Sour -milk
cheeses are prepared chiefly as an article of nutriment for the poor.
Only one kind, viz. the Glarner green cheese, constitutes an important
article of commerce and of export. The sour-milk cheeses are gener-
ally made only from skim-milk and butter-milk. Cream, hoAvever,
and even butter is often added to the curd, at the rate of 10 per cent

266

SCIENCE AND PRACTICE OF DAIRYING.

of its weight. The separation of tlie curd is effected, when the liquid
has become sufficiently sour, by simply warming at 37° to 50° C, or
by the addition of hot water. If the liquid be not sufficiently sour,
sour butter-milk is added before warming. At temperatures under
35° C. the separation is eftected very slowly and very imperfectly,
and at temperatures over 50° C. the curd is found to be friable and
too dry. In the preparation of sour-milk cheese, it ought not to be
forgotten that the sour liquid acts upon metals, and that the cheese
may become poisoned if the curd be allowed to stand for a long time

in bright copjDer kettles. For
this reason, heating should
only be conducted in copper
kettles plated with tin, and
the curd should be brought
into wooden vessels as soon
as separation is effected.
During the preparation of
numerous kinds of sour-milk
cheeses, the curd is kept for
some time before moulding,
and a species of fermentation
is allowed to go on in it.
During the ripening process,
everything depends on whe-
ther moulds are kept from
the cheese. 100 kilos, of skim-
milk or butter-milk, or a mix-
ture of skim-milk and butter-
milk, yield, according to
whether a greater or lesser
amount of pressure is applied, 8 to 13 kilos. — on an average 11 kilos.
— of fresh curd, and 5 to 8'5 kilos, of perfectly ripened sour-milk
cheese. 100 kilos, of milk should produce 7*5 to 9 '5 kilos, of fresh
sour-milk cheese, in addition to 3 to 3'5 kilos, of butter. All sour-
milk cheeses are salted in the vat, and many kinds have all sorts of
things added to them, especially herbs (zigerJdee). The smaller fresh
sour-milk cheeses under '3 kilo, in weight suffer a distinct loss in
weight during ripening, which, when the cheeso becomes slightly ripe,
amounts to about 30 per cent, and when the cheese is quite ripe, to
from 35 to 50 per cent or more. These small cheeses are generally

Curd Mill.

SOUR-MILK CHEESE.

267

sold when they begin to take on a yellowish external appearance,
or when they are surrounded with a j^ellowish rind some millimetres
thick. Many farmers do not themselves work the curd which they
have prepared, but sell it to the manufacturers, who carry on the
preparation of sour-milk cheeses on a large scale. The manufacture
of sour-milk cheeses is carried on in Germany to the greatest
extent in Hessen and Thuringia, in the Hartz, in the Riesen
Gebirge, and in several districts of Westphalia. Curd presses,
curd mills (figs. 76 and 77), and hand cheese moulds, machines for
brushing and washing the
cheese at the beginning
of the ripening, are the
utensils used in its manu-
facture. The sour-milk
cheeses made in different
countries are as follows : —

1. America. — Pot, Cot-
tage, Sour-curd, Sour-milk,
Queso de quincho, Queso
de palma metida, Queso
de mano.

2. Belgium. — Belgian
Sour-milk.

3. GerTnany. — Ost-
preuszische Glumse, Soft-
curd, Bauden, Alte Kuh,
Berlin, Soft - hand, Mar-
kischer Preszkase, Kinnen.
Sarz, Ihleselder, Pimp,

Nieheimer, Brand, Dresden, Sachsische Sour -milk, Thuringer
Caraway, Hartz, Main, Caraway small cheese. Health cheese, Sour-
milk, Potash,

4. France. — Peasant, Broccio.

5. Italy. — Chiavari.

6. Austro-Hungary. — Olmutzer Ouargeln, Borarlberger Sour-
milk, Sperr, Trocken, Montavoner Krauter.

7. Russia. — Livlander Sour-milk, Krutt.

8. Sweden. — Gammelost, Pultost, Knaost.

9. Switzerland. — Glarner, Schabziger.

Preparation of Potato Cheeses. — The preparation of potato cheeses is only

Cheshire Curd Mill.

268 SCIENCE AND PRACTICE OF DAIRYING.

carried out now to a very limited extent. These cheeses, which were
formerly made of different shapes, were at one time popular in Thuringia
and Saxony They were made by mixing certain quantities of curd with
good i^eeled potatoes, which were pounded down and mixed in the pro-
portion of one to one and a half parts of curd to two parts of potatoes.
They were then salted and flavoured according to taste with caraway
seed, well worked and laid in covered vessels, and allowed to lie for
two days in summer, and after the lapse of this period they were again
thoroughly worked and moulded. After two days they were placed upon
stands at a gentle temperature, till they became thoroughly dry, care being
taken, however, that they should not become cracked. If the cheeses became
too dry they Avere damped with beer or sour milk. The dried cheeses
were then laid in bowls with chickweed, and allowed to remain there for
fourteen days. In this way the cheeses acc[uired a good flavour.

125. Cheese-like Products from the Refuse of Cheese Manufactories.
— From the liquid refuse of cheese manufactories the following
products may be obtained: —

Alysost. — This is obtained by treating the whey which is obtained
as a bye-product in the manufacture of rennet cheese. It is much
liked in the hill districts of Scandinavia. It is moulded in the form
of parallelepiped -shaped pieces, possesses the colour of chocolate,
has a pleasant taste, and is slightly granular and of a soft texture.
It consists chiefly of milk-sugar, but contains, in addition, the albu-
minoid bodies present in the whey, lactic acid, some fat, and the
mineral constituents of milk, less what has been taken up by the
separated curd. In the manufacture of cheese from milk, 100 kilos,
of milk yield on an average 3 to 3"5 kilos, of butter, 4 to 5 kilos, of
fresh skim-milk cheese, and 6 to 7 kilos, of mysost.

Schottensicht, that is, the solids rising from the whey, are separated
out and utilized in Switzerland as well as in the hilly districts of
Germany and Austria. It is obtained by steaming the whey, and is
much the same as mysost.

Ziger Cheese. — When the licjuid residue of rennet cheese is
rendered acid and is heated almost to boiling point, the albuminoid
bodies which it still contains ai*e almost entirely precipitated in large
yellowish-white flocculent masses. This substance, which is known
in Germany, Austria, and Switzerland as Ziger, in France as Recuit,
and in Italy as Ricotta, is either consumed in a fresh state or worked
into ziger cheeses. The better-known Swiss ziger cheeses are, for
example, the Hudel-izig of the Canton Glarus, and the Mascarponis

THE LIQUID RESIDUE OF CHEESE. 269

of Bergell in the Canton Graublindeu. A mixture of fresh ziger
and cream, which is eaten in Savoy with pounded sugar as a dessert,
is known in that district universally as gruax de onontagne. From
calculations made by the author, it may be reckoned that 100 kilos,
of milk, in addition to the above-mentioned bye-products, will yield
7 to 8 kilos, of fresh unpressed ziger, or 2 to 3 kilos, of fresh pressed
ziger cheese.

The residue from sour-milk cheese manufactories is not, as a
rule, further treated. In Norway the curd whey remaining behind
in the preparation of Gammelost and Piiltost are here and there
steamed and worked into a stiff dry pulp, and after they have cooled
sufficiently are packed and sold under the name of Surprim.

126. The Liquid Residue of Cheese.— The liquid remaining behind
in the manufacture of cheese by rennet is known as whey, and
generally this word is sufficient to indicate perfectly the residue
from cheese. On theoretical grounds, however, it is desirable to
use two words for the purpose of distinction, viz. the words cheese-
milk and whey. Whey is the name we may apply to the liquid
remaining behind, after the removal of the curd from the cheese-
vat, from which butter can be obtained in the form of vorhruch, or
whey -butter (in fat cheeses and ziger). On the other hand, the
residue which is obtained after the removal first of the vorhruch
and then of the ziger, we shall call cheese-milk. The residue of
sour-milk cheese may be called curd-whey or curd-serum. The
composition of cheese-milk, whey, and curd-whey is, according to
investigations of the author, as follows:—

Cheese-niilk.

Whey.

Curd-whey.

Water,

93-15

93-31

93-13

Fat,

0-35

0-10

0-12

Js itrogenous matter,

1-00

0-27

1-06

Milk-sugar and lactic acid,

4-90

5-85

4-87

Mineral matter, ...

0-60

0-47

0-82

100-00

Nutritive ratio. ...

. 1:5-78

1:22-G0

1:4-88

From the residue left over in cheese - making, milk-sugar is
obtained, regarding which something will be said further on.
Usually it is converted into money by feeding swine with it in
the form of whey or curd-serum. If if be calculated that, on an
average, according to elaborate and extensive experiments which

270 SCIENCE AND PRACTICE OF DAIRYING.

have been carried out on this subject, for 1 kilo, of live weight
made one pfennig is expended, it may be assumed that such an
estimate is not too hiffh.

Attempts have been repeatedly made to manufacture the residue
from cheese manufacture into alcohol, or vinegar, or spirituous
licjuors, as whey-champagne and whey-punch, as well as to use it
in the baking of bread, instead of milk or skim-milk. None of these
methods, however, have as yet proved themselves to be profitable.

In baths and in places where the air cure is carried out, whey is
used, especially for people suffering from lung and chlorotic diseases,
and convalescents, since it exercises a favourable influence on the
digestion and condition of the invalid, if taken daily for some time
in suitable quantity. Should it be impossible to obtain whey for
this purpose from dairies, and if it be desired to prepare clear
whey on a small scale, this can best be effected by adding for every
kilo, of milk "10 gram of crystallized citric acid and 1 c.c. of rennet
solution of average strength, and heating to boiling, boiling for
fifteen minutes, and then filtering through thick linen.

According to the few investigations Avhich have been carried out, the
ash of the whey of goats' milk has the following composition : —

Potassium chloride, ... ... ... 50*00

Sodium chloride, ...
Potassium phosphate,
Calcium phosphate.
Magnesium phosphate,

10-00

21-00

14-00

5-00

100-00

The specific gravity of ordinary whey, or curd-whey, may be
said to lie between 1-025 and 1-028, and that of cheese-milk between
1027 and 1029, at 15° C.

127. Yield of Cheese. — With regard to the use of fresh or ripe
cheeses of different kinds, I have brought together in the preceding
paragraphs such information as the literature of the subject affords,
and as my own experience offers. In what follows I shall give, in
a few figures, a comprehensive survey of the subject.

The yield of cheese from milk is, as a rule, greater in the manu-
facture of soft cheeses than in the manufacture of hard cheeses, and
greater in the manufacture of fat cheeses than in that of skim-milk
cheeses. It is high when fat cheeses, which are immediately eaten or

YIELD OF CHEESE. 271

are for immediate use, are made. Broadly speaking, one may reckon
that 100 kilos, of milk will yield —

Of soft, fresh, fat cheeses for immediate consumption, 25 to 33 kg.
Of very soft fatty cheeses (Brie and Camembert, Neufchatel, &c.),

18 to 22 kg. of fresh, or 12 to 15 kg. of ripe cheese.
Of somewhat firmer, fatty, soft cheeses (Limburg, Remoudou), 13 to

16 kg. of fresh, or 9 to 11 of ripe cheese.
Of soft half-fatty cheeses (Limburg), 1'5 kg. of butter and 12 kg.

of fresh, or 9 to 11 of ripe cheese.
Of soft skim-milk cheeses {d la Brie, Camembert, Liverot, Back-

steinkasen), 3 to 3"4 kg. of butter and 7^5 to 12 kg. of fresh, or

6 5 to 9 of ripe cheese.
Of Roquefort cheese, on an average, IS kg. of fresh and 12 to 145

of ripe cheese.
Of fatty hard cheeses, made according to the American or English

method, 9 to 11 kg. of fresh, or 8 to 9 kg. of ripe cheese, and

"75 kg. of butter.
Of fatty hard cheeses, made according to the Dutch or Swiss

method, 8 to 11 kg. of fresh, 7 to 10 of ripe cheese, and "75 of

butter.
Of half -fatty hard cheeses, 7 to 10 kg. of fresh, 5 to 8 of ripe, and

16 of butter.
Of hard skim-milk cheeses, 5 to 7 kg. of fresh, or 4 to 6 kg. of ripe

cheese, and 3 to 3"5 of butter.
Of fresh-pressed curd, 8 to 12"5 kg. and 3 to 3'5 kg. of butter-milk.
Of sour-milk hand cheeses, 7*5 to 9"5 kg. of fresh, or 5 to 6 kg. of

ripe, and 3 to 3'5 kg. of butter.
Of Glarner Schabich, 10 kg. of fresh, or 6 to 7 of ripe cheese, and

3 to 3*5 kg. of butter.
Of Swedish and Norwegian Gammelost, 3"5 to 5"5 kg. of fresh, or

2 to 3 kg. of ripe cheese, and 3 to 3'5 kg. of butter.
Of fresh Mysost, on an average, in addition to butter and skim-milk

cheese, 6 to 7 kg.
Of fresh-pressed Ziger, in addition to butter and skim-milk cheeses,

2 to 3 kg.
Of whey in the manufacture of fatty cheeses, 73 to 88 kg., on an

average 81 kg. In the preparation of half-fatty cheeses, 72 to

80 kg., on an average 76 kg.; and in the preparation of

skim -milk cheeses, 66 to 76 kg., on an average 71 kg. In

the manufacture of soft cheeses, under otherwise similar

272 SCIENCE AND PRACTICE OF DAIRYING.

conditions, for every 100 kg. of milk made into cheese, there

are 5 to 7 kg. less of whey than in the case of hard cheeses.
The loss in cheese-making per 100 kg. of milk is, on a wide average,

about 3 kg., not including the loss which arises in the ripening

process.
128. The Chemical Composition and Analysis of Cheeses. — Cheeses,
both such as are destined to be consumed fresh, as well as those
which are allowed to ripen before consumption, are highly valuable,
and to a large extent also, favourite articles of food. In the first
place, they are rich in nitrogenous bodies. According to the method
of preparation and the age, they contain between 18 and 50 per
cent, on an average from 25 to 30 per cent, of nitrogenous matter.
In addition, from 25 to 46 per cent of fat, and a not inconsider-
able amount of mineral constituents, containing much phosphate
of lime, are found in them. The kilogram of nitrogenous substance
in cheese, more especially in skim-milk cheese, may be said to be
cheaper than in almost any other article of food. Skim-milk cheeses
are, however, as a rule, less pleasant in flavour and less digestible
than fat cheeses. Emmenthaler cheese, which is easily digested, and
of a fine mild flavour, satisfies all demands as a good suitable food. It
is on this account eaten with bread alone, or with bread-and-butter,
in larger quantities at one time than is the case with other cheeses.
A not inconsiderable number of the different kinds of cheeses are
used more as a bye-meat or appetizer than as an article of food
for satisfying hunger, or as the chief constituent of a meal.

The chemical investigation of ripe cheese is a very difficult
operation, which can only be imperfectly carried out, owing to the
decomposition products which arise from the albuminoids and the
fat during ripening, too little being known to permit of their being
easily distinguished and their percentage exactly determined. All
the complete analyses of ripe cheese at present available, with the
exception of a few of the more recent researches, give merely a super-
ficial and very unsatisfactory idea of the composition of cheese. In
these analyses, what is designated as fat is the entire amount of body
which has been extracted by ether or other fat solvent, regardless of
whether it consists wholly of fat or not. The percentage of protein,
or caseous matter, is generally expressed by a number obtained by
multiplying the percentage of nitrogen found with a constant
factor, viz. 6"25, which in the case of caseous matter is probably not
once right. A determination of this kind is of little value, even

CHEMICAL COMPOSITION AND ANALYSIS OF CHEESES. 273

although it be correctly carried out, because ripe cheeses contain, in
addition to unaltered nitrogenous matter, quite a number of pro-
ducts of the decomposition of nitrogenous bodies, which do not
belong to the group of albuminoids.

The investigation of fresh cheese is much simpler, since, in its
case, the individual constituents of the milk, although they have
partly undergone change, are yet in a condition which does not
offer especial difficulty in their separation and determination.

In the investigation of fresh cheese the following method may be pur-
sued : —

(1) Determination of Water and Fat. — The sample of cheese to be
investigated is cut into small square pieces, of which 2*5 to 5 grams
exactly are Aveighed out, and carefully warmed to 40° C. They are then
brought, in an open glass capsule, under the receiver of a hand air-pump, the
air from which is pumped out. It is left for some time standing, again
warmed, and this is again repeated, until no fui'ther loss in weight is
observed. It is then digested several times Avith cold ether, removed
from the capsule, and pressed in a dish. It is then brought on to a
weighed filter; the capsule and the dish being rinsed Avith ether. The
cheese is then extracted on the filter with warm ether, the difi'erent
Avashings being all brought together. The cheese, from which the fat has
thus been extracted, is dried at from 100° to 110° C, cooled, and is
Aveighed on the filter, the Aveight of Avhich is deducted. After the ether
has been distilled off from the ether extract, the fat remaining behind is
dried carefully at from 100° to 105° C, cooled, weighed, and the percentage
of fat of the cheese thus estimated. By subtracting the sum of the Aveight
of the cheese from Avhich the fat has been extracted, and AA^hich has been
dried, and of the fat, from the Aveight of the cheese originally taken, the
percentage of Avater in the cheese is obtained. If the largest part of the
water has not been removed before its treatment Avith ether, it may
happen that in the extraction process small quantities of mineral salts,
Avhich are soluble in water, and perhaps also small quantities of milk-
sugar, may go into the extract, and render the determination inexact. In
the investigation of sour-milk cheeses, it must be remembered that the
lactic acid present is soluble in ether. On this account the determination
of fat must be carried out in a specially prepared sample, which has been
rendered AA-eakly alkaline Avith soda, and then carefully dried.

(2) Determination of Nitrogenous Matter. — This is determined in another
quantity of the cheese, or in that portion from Avhich the fat and the
water have been separated, either volumetrically, by Dumas' method, or
by the Kjeldahl process, the nitrogen obtained being multiplied by the

(M175) 8

274 SCIENCE AND PRACTICE OF DAIRYING.

factor 6"39, on the assumption that the albuminoid matter of the milk
contains 15*65 per cent of nitrogen.

(3) Determination of Ash. — This may be carried out in a special sample
of the cheese, or on the portion Avhich has been used for the determination
of water, observing the precautions which are necessary in this process.
The ash is determined by burning a small portion.

(4) The Determination of Milk-sugar.— The percentage of milk-sugar may
be determined in perfectly fresh cheese by difference, if all the remain-
ing determinations have been carried out in duplicate with great care.
If it be desired to determine the milk-sugar directly, this may be done in
a water extract, obtained by taking a portion of the cheese dried under
the air-pump, rubbing it up thoroughly with pure sea-sand, and boiling
it repeatedly with pure water. In order to separate the albumin from
this water extract before treating it with the copper solution, it is necessary
to acidify it with acetic acid, boil, and then filter.

In a perfectly exact analysis of fresh cheese, it must be assumed that
the fat of the milk contains lecithin, and that, therefore, small quantities of
nitrogen will be found in the fat of the cheese.

In the investigation of ripe cheeses there is no method which can be
recommended as suitable or trustworthy. Manetti and Musso recommend
the following: — Determination of the percentage of water and bodies
volatile at 115° C; preparation of a carbon bisulphide extract; prepara-
tion of an alcoholic extract; preparation of a Avatery extract; determination
of the quantity of bodies insoluble in bisulphide of carbon, alcohol, and
water; determination of the ash; determination of ammonia; determina-
tion of the sum of the acids present; determination of the nitrogen; and
finally, the determination of the nitrogen and ash in the different extracts,
as well as the determination of the nitrogen and ash in the residues of the
dififerent extracts.

As an example of the chemical composition of certain kinds of fresh
cheese, and of products resembling cheese, the following figures may be
given : —

Neufchatel Limburg
(Double Fat (Fat
Soft Cheese). Soft Cheese).

Emnienthaler

(Fat
Hard Cheese).

Backstein Raden
(Skim-milk (Skim-milk
Soft Cheese). Hard Cheese).

Olmiitzer
(Sour-milk
Cheese).

Water

.. 34-5

35-7

36-1

73-1

57-3

44-6

Fat, ...

.. 41-9

34-2

29-5

2-8

3-5

3-4

Nitrogenous
matter, . . .

Non-nitrogen-
ous matter,

j 13-0

! ..0

24'2
3-0

28-0
3-3

19-8
2-2

33-0
2-9

V41'l

Ash, ...

3-6

2-9

3-1

2-1

3-3

10-9

100-0

CHEMICAL COMPOSITION AND ANALYSIS OF CHEESES. 275

Water,

Ziger.
68-5

Mysost.
23-6

Fat,

3-1

16-3

mtrogenous matter,

22-1

8-9

Milk-sugar,

3-2

37-3

Lactic acid,

0-8

1-1

Remaining constituents,

8-1

Ash,

2-3

1000

100-0

A study of the history of the manufacture of cheese, as carried
out in different countries, shows that in three countries, viz., in Swit-
zerland, in Holland, and in England, special kinds of preparation
methods for the manufacture of hard cheeses have been in use from
a very early period.

In South German hill districts, in Austro-Hungary, and over
Italy, the Swiss method has been followed; in Schleswig-Holstein,
in the Rhine Province, and over the whole of North Germany, the
Dutch method has been adopted; and in the United States of
America the English method has been preferred. France produces
the finest and the most popular of soft table cheeses, Switzerland
the best of hard cheeses, and Upper Italy the highly-prized Reib
cheese. In Switzerland the manufacture of cheese is much more
extensive than the manufacture of butter; the contrary is the
case throughout Scandinavia, that is, in Denmark, Sweden, and
Norway, as well as in Finland, in the Russian East Sea Provinces,
in the whole of North Germany, and in a large part of France.
The manufacture of butter, as well as of cheese, is carried on in
North America, Great Britain, Holland, a part of France, South
Germany, and over Italy. In Austro-Hungary, the manufacture
of cheese, indeed the whole business of dairying, has up till the
present time not received the amount of attention which has been
devoted to it in most other countries.

CHAPTER VI.

PREPARATION OF KEEPING MILK, FERMENTED MILK, AND THE
BYE-PRODUCTS OF MILK.

129. Keeping Milk. — By keeping milk, is understood milk which
by heating, or by heating and other suitable treatment, possesses
the property of being able to keep, without becoming decomposed,
for a longer time than ordinary milk. As long as milk stands boiling
without coagulation, and possesses no other foreign flavour than a
slight taste of cooked milk, it may be regarded as a good keeping
milk. The keeping qualities of milk, on the other hand, may be
increased to such an extent, that it will keep for days, or months, or
for a much longer period. In such cases the milk may possess its
original percentage of water, or it may lose a portion of it by
becoming thick.

130. Pasteurized Milk. — By such milk is meant that which has
been heated, for a shorter or longer period, to a temperature under
the boiling point of water, but high enough, as experience has
shown, to kill most of the microscopic fungi. The temperature
which meets these conditions, and which is consequently commonly
used in Pasteurizing, lies between 56° and 80° C. Within these
limits, the higher the temperature, the shorter is the period in which
a distinct effect is produced. It would be very extraordinary, indeed,
if milk were rendered free from spores by Pasteurizing. Since
Pasteurized milk is scarcely ever kept free from spores, it possesses
only, as a rule, a slightly increased keeping property. This is
explained by the fact that the lasting spores of certain kinds of
bacteria, which are not uncommonly present in milk, can withstand
for a long time the application of such heat as is applied in Pasteur-
izing, and that there are bacteria which only begin to develop at
temperatures over 50° C. ; indeed, there are some which even rapidly
increase at temperatures of from 70° C. to 75° C. Fortunately
such bacteria as agree with these high temperatures are generally
uncommon, and are only very rarely found in milk. Experiments
have shown that in Pasteurizing, the vegetative forms of nearly all
bacteria, and especially, also, of the most dangerous pathogenic germs,

276

PASTEURIZED MILK.

277

such as cholera, typhoid, and tubercle bacilli, are killed. This, and
this alone, is what is effected by Pasteurizing, and should always be
effected by it. On this account, milk which has been so strongly
and so long heated that the above results have been safely obtained,
or milk in which the lasting forms, and the forms of such bacteria
as prefer unusually high temperatures can alone be present, is
named correctly Pasteurized milk. Correctly speaking, Pasteurized
milk is, for example, milk
which has been heated for
15 minutes at 75° C. or for
30 minutes at 68° C. The
action effected by Pasteur-
izing is the more perfectly
brought about the moie
carefully the operation is
carried out. If it be de-
sired to take every pos-
sible precaution, attention
must be paid to having
the milk contaminated
as little as possible in
the process of milking.
The Pasteurizing appar-
atus should be cleaned for
fifteen minutes before use,
and the cooling of the Pas-
teurized milk should be
carried out as quickly as

possible in a cooler, which should also have been previously steamed.
The cooled milk should then be put in steamed vessels, and care
taken that it should not be left to stand for any time in uncovered
receptacles. Properly Pasteurized milk keeps at ordinary animal
heat for 20 to 24 hours at 20° C; about 60 hours at 12 Ho 15° C;
72 hours, and often even longer at lower temperatures, in a con-
dition which admits of its being boiled without coagulation. It
only possesses a flavour slightly suggestive of boiled milk, and may
be converted into cheese, since its susceptibility to rennet has only
been weakened to a very slight extent. In spontaneous coagu-
lation it forms a comparatively spongy coagulum. Occasionally it
is not lactic bacteria which induce, after a lapse of time, coagula-

Fig. 78.— Laval Milk Scalder.

278

SCIENCE AND PRACTICE OF DAIRYING.

tion of Pasteurized milk, but rennet and butyric acid bacteria. In
such cases the coagulated milk exhibits only a slightly weak acid
reaction, and shows near the surface a thin whey-like layer. If
the creaming be effected, as is now beginning to be customary, by

centrifugal force at 75° C,
and the milk be kept
fifteen minutes at this
temperature, the cream is
obtained, as well as the
skim -milk, in the same
condition as ordinary Pas-
teurized milk. If the
creaming operation be
followed at the tempera-
ture which is now cus-
tomary, of 25° to 35° C,
the skim-milk is often
Pasteurized (fig. 78) in
order to impart the neces-
sary keeping qualities to
it, and to permit of its
regular transport to other
places. Cream for butter-
making should only be
slightly Pasteurized if it
be intended to be kept for
a few hours only, or if it be
intended to be soured with
a pure culture of lactic
ferment for the purpose
of being made into butter.

Fig. 79.— Pasteurizing Apparatus (Burmeiater & Wain).

At the present time twelve different Pasteurizing apparatus for milk are
known. The whole of the apparatus (figs. 79 and 80) have this in common,
that the milk is stirred by metal paddles, which are heated by steam or
boiling water. They are brought up as quickly as possible to the tempera-
ture of 65° to 80° C, and have an uninterrupted flow of milk passing
through them. They may be divided into classes, viz. those in which the
milk flows out over a ribbed hot-plate, and those in which the heated
milk flows through differently constructed closed spaces. All apparatus,
without exception, suffer from two defects. The first consists in the

PASTEURIZED MILK.

279

fact that in consequence of the strong and rapid heating of the nitro-
genous matter, the milk forms a firm crust on the hot surface. This has
to be prevented by special arrangements of the best possible kind. The
second disadvantage consists in the fact that the apparatus works con-
tinuously, and that the only thing taken into account is to bring the milk

Steam

Milk

Fig. SO.— Pasteurizing Apparatus (LefeUit).

quickly to a certain high temperature, and as soon as this temperature
is reached, to allow it to flow away. In order to increase the capacity of
the machine per hour, what is aimed at is to shorten as much as possible
the period of the action of the temperature on the milk, and to raise the
final temperature as high as possible. Since no apparatus among those
above described may be said to yield with certainty properly Pasteurized
milk, not one of them can be described as effecting what they ought to

280 SCIENCE AND PRACTICE OF DAIRYING.

effect. This is, however, no discredit to the makers, who do not know, and
could not knoAv, in constructing their apparatus, the cause of the defect.
If it be desired in Avorking Avith the apparatus in use to make sure that
all the most dangerous pathogenic bacteria, and the vegetative forms of
nearly all the remaining kinds of bacteria, have been destroyed, care must
be taken, in the first place, that the milk be subjected in the apparatus to
75° C, and further, that the hot milk should be kept in special vessels for
30 minutes at a temperature of over 70° C. There is no Pasteurizing
apparatus, therefore, as yet, which gives in a convenient, simple, and
certain manner properly sterilized milk. Whether it is possible to manu-
facture such an apparatus, without doing away with the continuous flow
of milk, must be decided by practical makers. Possibly, as H. Bitters has
pointed out, the Pasteurizing apparatus of the future will be constructed
in such a manner that the milk Avill not be heated in a continuous flow,
but that it will be heated intermittently, and for a definite and high tem-
perature, for a certain time.

131. Sterilized Unthickened Milk. — The perfect sterilization of
milk, that is, the destruction of all spores in it, is extremely difficult.
It can be effected, if desired, in a twofold manner. In the first place,
it may be effected by heating the milk in strong closed vessels for
several hours at a temperature of 110° C, or for 30 minutes at a
temperature of 130' C; or, secondly, by heating the milk on eight
consecutive days, for two hours each day, at a temperature of
65° C, and keeping the milk in the interim period at a tempera-
ture of 40° C, that is, by intermittent sterilization, a method first
employed by Tyndall. In the first method of treatment the value
of the milk is lessened, since the particular qualities which are
specially prized in fresh milk are entirely lost. The second method
of treatment is so inconvenient, and consumes so much time, that
although by this method the value of the milk is little affected, it
cannot be carried out on a large scale. The perfect sterilization of
milk by either method is of little practical importance, and can only
be carried out in the laboratory for experimental purposes. In
practice, one must be content with the empirical method of stei'i-
lization, in order to change the milk as little as possible, and be
satisfied with destroying the vegetative kinds of bacteria, along
with such pathogenic bacteria as may be present, and with acting
upon the lasting spores, which may not be destroyed, in such a way
that their capacity for development may be weakened, and that
they may at ordinary animal heat only exercise a dangerous action

STERILIZED UNTHICKENED MILK.

281

after being five to eight days in the milk, or, at ordinary tempera-
tures, only after a lapse of weeks or months.

Sterilized milk, as almost universally prepared at present, is
only sold in glass bottles, provided with hooped iron stopcocks
and with a lead seal, and holding from '250 to '33 kilos, of milk. It
has a flavour of boiled milk; the colour is either almost unchanged

Pig. 81.— Sterilizing Apparatus.

or is of a distinct bright yellow. It contains no soluble lime salts
and no soluble albumin. It is unsusceptible to the action of rennet,
and yields, when coagulated with acids, a fine flocculent coagulum.
The author, in collaboration with Dr. Aug. Morgen, showed, in
1883, that the nitrogenous matter in milk, which has been submitted
to high temperatures, is somewhat more digestible than in fresh
milk, a fact which has subsequently been confirmed by Raudnitz
and Stutzer.

Nearly all sterilized non-thickened milk is used for children, and
is used without delay. Although it is easy enough to keep it for
weeks, it is not well suited for this, since it is very quickly sepa-

282 SCIENCE AND PRACTICE OF DAIRYING.

rated by the action of gravity into cream and skim-milk, which do
not subsequently admit of perfect admixture. On this account, un-
like wine, beer, and other beverages, it cannot be kept in the cellar
for a long time, nor is it suited for use on board ships, nor for trans-
marine export. This method of preserving milk is open to the objec-
tion that seven-eighths of the weight of the milk consists of water, and
on this account it can scarcely be described as possessing a valuable
economic property, which distinguishes articles used for transport.
It is not, therefore, suited for keeping for a long time, or for export
on a large scale. Condensed milk is better adapted for this purpose.

A well-known apparatus for sterilizing large quantities of milk, in the
method above described, is the sterilizing apparatus of Neuhausz, Gron-
wald, and Oehlmann (fig. 81), which is manufactured of four different
sizes for treating 50, 104, 150, and 238 bottles I'espectively

132. Condensed Milk. — The exiDoriments and attempts which have
been made to convert milk by various methods into a condition
in which its most valuable and most essential properties may re-
main unchanged for a long time, if possible for years, date back to
the early part of the present century. Although the many and
various attempts which were made, up to the middle of this century,
were all failures, they cannot be regarded as valueless, since they
paved the way to the method in which the object aimed at can
alone be effected. In the first place, they have shown that milk, in
order that its usefulness for transport should be increased, and that
at the same time its keeping power be strengthened, must be deprived
of a portion of its water; and in the second place, that steaming the
milk in vacuum, at a temperature under 70° C, is necessary, and
that these are indispensable conditions to the utility and value of
the process. In the earliest attempts made in the United States of
America to change milk into an article which might admit of being
kept, the experiment was made of withdrawing all the water from
the milk, and of pressing the dry substance, to which small quan-
tities of bicarbonate of soda had been added, into cakes. Messrs.
Dalson, Blatchford, and Harris set up a manufactory about the year
1850, in the neighbourhood of New York, in which cakes of milk
were made according to the directions of E. N. Horsford. It was
believed that everything had been discovered and the desired object
attained. It was soon found, however, that the new preparation did
not come up to expectation. The milk cakes kept badly, as the fat

CONDENSED MILK.

283

in them developed a slightly rancid flavour; while they did not
completely dissolve. On mixing them with water, a liquid was ob-
tained which no doubt possessed the appearance of milk, but was in
reality nothing else than a mixture of milk powder in water, since
the nitrogenous matter of the milk which had been dried did not
dissolve or swell out; that
is to say, did not assume
the condition in which it
was originally present in
the milk. This result raised
the question of whether it
was possible to obtain a
substance under the name
of milk, by fully drying
the milk and by again dis-
solving it, and finally de-
cided it.

On the 19th of August,
1856, Gail Borden took out
a patent in America for the
preparation of condensed
milk by use of a vacuum
pan (fig. 82), without the
addition of sugar, or of any
other foreign substance.
The viscous condensed milk,
prepared by him on a com-
mercial scale, and packed
in open cans, excellently
fulfilled all the require-
ments if not kept too long,

but suffered from the drawback that it could be kept unchanged
only for a few weeks. Gail Borden then tried condensed milk with
the addition of sugar, packed in air-tight soldered cylindrical metal
tins. This method at length solved the problem in a satisfactory
manner. As the method of preparing condensed milk at present
in practice is essentiallj^ the same as that introduced bj^ Gail
Borden, his name is with justice regarded as the discoverer of a
method of condensing milk.

In the year 1865, C. A. Page, at that time consul in Zurich,

Vacuum Tan Tor Condensing ililk.

284 SCIENCE AND PRACTICE OF DAIRYING.

erected a factory in Switzerland for the preparation of condensed
milk, prepared with sugar. He was succeeded by the Anglo- Swiss
Condensed Milk Co., which founded in 1866 at Cham, on the Lake
of Zug in the Canton of Zug, a large factory, which was the first
factory for the manufacture of condensed milk started in Europe.
The company still exists, and in addition to its chief factory at
Cham, has branches in England, in Switzerland, and South Germany,
and practically supplies the entire European market with condensed
milk. In the course of time many other similar factories have been
erected in different districts, nearly all of which, however, have come
to grief. The experience which has been acquired up till the present
time in the preparation of condensed milk, points to the fact that
the fresh milk should be previously warmed, with 12 to 13 per cent
of its weight of cane sugar — beet sugar has proved itself unsuitable,
— and then condensed in a vacuum pan to about one-third or one-
fourth of its volume.

Thickened milk possesses a white or whitish-yellow colour, according
to its age, and is of a very sweet pleasant flavour. It has a thick pulpy
consistency, and has the power of keeping for a long time.

If condensed milk be mixed Avith four and a half times its weight of
pure lukewarm water, it is perfectly dissolved, and forms a milky, sweet,
and pleasant liquid, which possesses the flavour of ordinary fresh milk.
If allowed to stand for some time, a layer of cream is thrown up, which
may be made into butter.

According to all the available data collected by the author, condensed
or preserved milk, prepared by the addition of cane-sugar, has the follow-
ing composition: —

Avei'age.

Limits of Variation.

AVater, ...

25-68C

12-43 to 35-66 percent.

Fat,

10-985

7-54 „ 18-78 „

Nitrogenous matter, ...

12-325

7-79 „ 20-14 „

Milk- and cane-sugar, . . .

48-662

41-25 „ 53-89 „

Mineral matter,

2-342

1-56 „ 3-87 „

100-000

The relation between milk-sugar and cane-sugar is as folloAvs : —

Average. Limits of Variation.

Milk-sugar, ... 16-288 per cent. 10-82 to 18-35 per cent.

Cane-sugar, ... 32-374 „ 24-11 „ 40-48 „

CONDENSED MILK. 285

The specific gravity of preserved milk, containing cane-sugar, at 15" C,
varies between 1-2540 and 1-4038, being on an average 12820. Preserved
milk, without the addition of sugar, which is much used in the United
States of America, has not been prepared in Europe since 1880. The
chemical composition of American thickened milk, without the addition of
sugar, is as follows : —

Average.

Limits of Vaiiation.

Water,

48-595

46-40 to 53-54

per cent

Fat,

15-668

13-12 „ 19-80

Nitrogenous matter,

17-806

13-61 „ 26-50

Milk-sugar,

15-403

12-50 „ 17-75

Mineral matter,

2-528

2-00 „ 2-96

100-000

The specific gravity of American thickened milk is, on an average, at
15° C, 1-136. Attempts to condense skim-milk, mares' milk, and goats'
milk, have also been made.

Shortly after the method introduced by Scherff for the steri-
lization of milk had become known, the idea was carried into effect
of rendering the condensed milk capable of being kept by sterilizing
it, and thus dispensing with the addition of sugar, which, by
imparting to it a very pronounced sweet taste, rendered it disagree-
able to many people. For this purpose experiments were carried
out during the years 1881 to 1883 in different parts of Germany
and Switzerland. Sterilized condensed milk was best obtained by
purifying the fresh milk by the application of centrifugal force,
and then boiling it in order to coagulate the albuminous part of
the nitrogenous matter. This was condensed in vacuum-pans to a
third or fourth of its original volume, and poured into metal
vessels of the same shape and size as are used in the factor}- at
Cham. The vessels, after being filled and soldered, are placed for
a short time at a temperature of about 120° C, the keeping quality
of the substance being tested by submitting it for a few weeks to
a temperature of from 30° to 40° C, and after the lapse of tliis
time seeing whether there have not been indications of fermen-
tation shown by distention at the bottom or at the top of the
vessels. If it be neglected to heat up the milk before it is con-
densed, the albumin is coagulated during sterilization, and renders
the contents of the can lumpy.

286 SCIENCE AND PRACTICE OF DAIRYING.

If the preparation of condensed milk without the addition of cane
sugar is carried on with the necessary precautions, the product obtained
is a body possessing great keeping properties, which, when dissolved
in a suitable quantity of pure water, yields a liquid possessing all the
properties prized in fresh milk, and which indeed leaves little to be
desired. Good milk of this sort is manufactured by the manufactory of
Drenckhan, in Stendorf, near Eutin, and others. The chemical analyses of
several samples of such milk yield the following average compositions: —

Sampl

es from Stendorf.

Bremen

Water,

66-2

63-8

Fat,

8-4

9-8

Nitrogenous matter, .

10-9

10-4

Milk-sugar, ...

12-3

13-7

Ash,

2-2

2-3

100-0

The specific gravity of condensed milk of the above composition at
15° C. is about M.

133. Fermented Milk.^ — By inducing alcoholic fermentation in
milk by suitable means, it is possible to prepare from it spirituous
beverages. Two beverages of this kind are known, viz. kephir and
koumiss, which are prepared by the aid of different kinds of fer-
ments. In the preparation of these two beverages, it is found that
during the alcoholic fermentation, going on at the expense of the
milk-sugar, a decomposition of the milk takes place, accompanied
with the formation of lactic acid, and the casein separates out in a
solid form. Since this decomposition does not exceed certain well-
defined limits, and the quantities of lactic acid and alcohol do not
exceed a certain amount, the beverages cannot be kept at the
ordinary temperatures for any length of time without a certain loss
of their beneficial properties: but must be consumed when they are
only a few days old. Kephir and koumiss possess a frothy appear-
ance, and a taste resembling butter-milk, and contain the casein in
the form of a fine suspended coagulum. They are as nutritious as
they are easily digested, and exercise, when regularly taken for some
time, an excellent dietetic action, which may be ascribed chiefly to
the percentage of milk-sugar, alcohol, and carbonic acid they
contain. Good kephir should not contain more than 1 per cent of
alcohol and lactic acid, and good koumiss not more than at the
most 2 per cent of alcohol and 1 per cent of lactic acid.

KEPHIR. 287

Under fermented milk may be mentioned the " ropy" milk which
is still prepared in Scandinavia. The fermentation which takes
place in this kind of milk has, however, nothing to do with alcoholic
fermentation.

134. Kephir, or Kefir, Kyphir, and Kafir, and, as it is known in
the Caucasus, Kyppe, was for long only known to the hill-dwellers in
the Caucasus. In Germany it first became known in the year 1882.
It is prepared from the milk of different mammals, chiefly from
cows' milk, with the help of a special ferment. This ferment, the so-
called kephir gi-ains, which are granular lumps about the size of peas
or beans, of a hard nature, and of a yellow colour, is first dissolved
in water, to which milk is added. After a few hours, at a suitable
temperature, fermentation takes place, accompanied by an active
evolution of gas, which is accompanied with a slight characteristic
noise. After two or three days the kephir is ready for use. By
frequently shaking the vessel in which the kephir is contained,
first the separation of cream, and subsequently the formation of a
lumpy coagulum, are retarded. The kephir grains, which are known
in the original habitat of the kephir as the " Prophet's grains ",
on account of their value, consist of yeast cells and bacteria,
the nature and action of which has been investigated by Hueppe.
The results of his investigations have been discussed in § 44.
They convert a portion of the milk-sugar into lactic acid, and
another portion into alcohol and carbonic acid, but they do not
appear to alter the nitrogenous matter of the milk, at any rate not
to any extent. Kephir is best prepared at 12° to 15° C, since the
fermentations at this temperature proceed quietly, and the lactic
fermentation especially is delayed to a desirable extent. The casein
separates out at the beginning of the fermentation in a finely
flocculent condition, which, as long as the evolution of carbonic acid
actively continues, collects in the upper portion of the bottle, above
comparatively clear whey, and which later on sinks to the bottom,
and may thus be perfectly distributed throughout the liquid by
shaking.

Good kephir should foam, and should neither taste strongly acid
nor possess a lumpy coagulum. It is used as a tonic for convales-
cents and weak people, and is specially adapted for those patients
in whom it is desired to raise the general strength of the system.
Its action in all cases is excellent.

288 SCIENCE AND PRACTICE OF DAIRYING.

In the preparation of kephir, the first point of importance is to bring
the kephir grains to a state of great activity. For this purpose they are
soaked in water at 30° C, allowed to stand for several hours, and then
they are drained off. The swollen grains are then Avashed with pure
water. They are put in ten times the quantity of boiled milk, and cooled
to 20° C. They are left standing at 20° C, repeatedly shaken, and after
the lapse of an hour the milk is poured off. This is repeated for six or
seven days, or even for a longer period — so long, indeed, as the liquid
possesses the smell of sour milk, and till the grains are perfectly swelled
and begin to rise to the surface.

The grains thus prepared are again put in ten times their weight of
milk, which has been boiled, and then cooled to 20° C. They are allowed
to stand half a day at 20° C, are filtered through gauze, and placed in
new milk in the same manner. The filtrate which is poured off, and
which is not usually pleasant, is poured into half -sized champagne bottles
to the extent of 75 c.c, which are then filled Avith boiled milk, cooled to
20° C, and corked. The bottles are allowed to stand at 15° C, and
during the first day are hourly shaken, and after two to three days are
used. The SAvollen kephir grains Avhich are used must be freshened up
every eight days. In order to do this they are washed with pure Avater,
soaked in a 1-per-cent soda solution, and left to steep in it for about tAvo
hours. They are then vigorously stirred, and Avashed again Avith
Avater.

Among the feAv scientific investigations Avhich have been carried on
up till noAv Avith regard to kephir and its preparation, the bacteriological
investigations of Hueppe and the chemical investigations of Hammersten
are the most striking. According to Hueppe, the kephir grains not only
cause a lactic and alcoholic fermentation, but also peptonize a portion of
the casein and albumin in milk. Hammersten, on the other hand, has
shoAvn that in kephir, bodies of the nature of peptone are only present in
small and diminishing quantities, and that true peptone — that is, albu-
minoid bodies Avhich are precipitated by saturating the solution with
sulphate of ammonia — do not occur. He has further shown that kephir
casein is not practically different from milk casein. It is true that it is
less soluble in the carbonates of the alkalies, and dilute salt solution and
dilute hydrochloric acid, than milk casein. Since, hoAvever, casein, sepa-
rated by the spontaneous coagulation of milk, is of a similar nature, it
cannot be said that in the preparation of kephir from milk there is any
real change in the condition of the casein. Three samples of kephir from
Gothenbui'g, Avhich Hammersten has submitted to accurate inA'^estigation —
about the age of Avhich nothing is stated, but Avhich appeared to be about
four, or at the most, six days old, — had the following average composition: —

KOUMISS. 289

Water, 88-915

Fat, 3-088

Casein, 2-904

Lactalbumin, ... ... ... "186

Peptone, -067

Sugar, 2-685

Mineral matter, -708

Alcohol, -720

Lactic acid, ... ... ... '727

100-000

With regard to the specific gravity of kephir, Ave have no data.
Probably it is a little lower than that of milk, but not much different.

Struve found in kephir grains which he had examined 11-21 per cent
of water, 3-99 per cent of fat, 51-69 per cent of albuminoids, of which
10-98 per cent were soluble in water, 10*32 per cent soluble in ammonia,
and 30-39 per cent soluble in dilute soda solution, and 33-11 per cent
in an insoluble condition.

If it be desired to keep kephir longer than three or four days, it must
be laid in ice. G. Marpmann recommends that the kephir be sterilized
as soon as it has acquired the desired condition, in order that the process
of fermentation may be stopped.

The kephir ferment may be kept for half a year or longer, without
losing its vitality, if it be thoroughly dried in the sun in a cool dry place.
At present kephir can be easily obtained in every large town in Germany.

135. Koumiss. — Koumiss, or, as it has been called, milk-wine,
{vinu7)i lactis, or lac fermentaturii), is milk which has undergone
alcoholic fermentation. In taste and smell it resembles butter-milk,
or slightly sour whey, and presents a foamy appearance. It contains
its casein in the form of a very fine floating curd. Koumiss was
originally prepared in the steppes of the south of Russia and Asia,
where it has been used for hundreds of years by the different
nomadic tribes inhabiting these districts. It is chiefly prepared
from mares' milk, but may also be prepared from skimmed cows'
milk. The best koumiss prepared from mares' milk is said to be
that manufactured in the Russian province of Orenburg. Good
koumiss is in every respect very similar to kephir, although inferior
to it, and is used very much in the same way. In Russia, mares'-milk
koumiss has been long used for sleeplessness, and it was formerly
the custom in summer to send invalids undergoing the koumiss cure

( M 175 ) T

290 SCIENCE AND PRACTICE OF DAIRYING.

to a Cossack village in the steppes. At present there are, in different
districts of Russia, at Samara, Odessa, and at Ufa in the Urals, and
elsewhere, well-equipped establishments, conducted under the direc-
tion of physicians, where the koumiss is prepared. With regard to
the nature of the koumiss ferment, no extensive investigations have
as yet been carried out, nor has the chemical composition of koumiss
been so exactly determined as that of kephir.

As already stated, the Avord koumiss is derived from the name of an
old tribe, the Kumanen, mentioned by Xenophon and Pliny, who first pre-
pared koumiss, and who in the course of time transmitted the knowledge
to other tribes. There is historical evidence to show that koumiss was
already known to the Tartars as early as the thirteenth century.

Koumiss has been prepared by different methods in the past. One
method was by putting old koumiss, or the residue obtained by drying
koumiss in the sun, into a vessel, pouring fresh mares' milk in, and stirring
for fifteen minutes, the mixture being left to stand all night. Next day
fresh milk was again added, and the mixture again stirred, this being
repeated as often as possible in the course of the day. By this method
a weak preparation of koumiss is obtained in the evening, which may be
transferred, with the exception of a small residue, to another vessel. In
order to prepare more koumiss, fresh milk is added to this residue, and
the same process carried out. In this Avay, on the evening of the third
day, a preparation of weak koumiss, as well as a preparation of fairly
strong koumiss, is obtained. This process may be repeated as often as
desired.

An approved method of preparing koumiss from skimmed cows' milk
is as follows: — 100 kilos, of skim-milk, obtained from the separator, and
mixed with 42 kilos, of water, 1*75 kilos, of ordinary sugar, '78 kilos, of
milk-sugar, and 160-180 grams of yeast, is allowed to stand for 32 hours at
37° C. During this period the mixture is stirred about six times at equal
intervals. It is then carefully decanted into champagne bottles, corked
and fixed with wire, and the bottles left in a cellar at a temperature of
12° C. It is not desirable to keep it, at the very most, more than six days
at this temperature, since it gets too sour.

Good koumiss, six days old, has a specific gravity of 1*008 to r020,
and the following composition : —

*-^ A

Mares' Milk Koumiss.

Skimmed Cows' Milk
Koumiss.

Water,

91-535

88-933

Fat,

1-274

•854

Albuminoids,

1-913

2-025

94-772

91-812

ROPY MILK. 291

136. Ropy Milk. — The so-called "ropy" milk is milk which has
been converted by the fermentation of certain kinds of bacteria into
a peculiar condition. It is of a thickish uniform leathery consistency,
and runs, when poured from a spoon, in threads of considerable
length, which often draw out to the fineness of hairs. It tastes
slightly sour, contains its casein in the form of an extremely fine
suspended flocculent powder, and, at a comparatively low tempera-
ture, may be kept for months in an almost unchanged condition.
It is much liked in Norway and in Northern Sweden and Finland,
where it forms an article of commerce. The author has seen such
ropy milk at the market at Helsingfors, whither it had been brought
in little wooden barrels by the peasants living in the neighbouring
districts. The method in which lange milch is prepared in the
above-mentioned coimtries we do not exactly know. It is also
unknown whether its condition is due to zoogloea-building bacteria,
or bacteria which convert the milk-serum into a thready condition
through change of the milk-sugar. The author is not aware of any
accurate analyses that have as yet been made of ropy milk.

Lange milch is not used in Germany as an article of food. It is,
however, occasionally known as an undesirable disorder in milk. As such
disorders are not altogether uncommon, and, as the author knows by
experience, often occur in well - conducted dairies, it follows that the
bacteria which induce this thread-like consistency in milk or cream must
be of pretty wide occurrence. It has been asserted that ropy milk may
be prepared by the help of a plant, Pinguicula, in those countries in which
it is regularly made. The author doubts this, however, since in repeated
experiments with the Pinguicula vulgaris and the Pinguicula alpina he has
never succeeded in producing this thready consistency in milk. If, how-
ever, it does take place, he believes it must be attributed to the agency of
bacteria, which change the milk in this way, and which find in the above-
mentioned plant a congenial nourishing soil, and hence are often found
in it.

137. Milk-sugar. — Of all the bye-products of milk, milk-sugar is
by far the most important. Milk-sugar, the properties of which
have been more particularly described in § 7, can never, on account
of its hardness and its only slightly sweetish taste, supplant
cane- or beetroot-sugar for ordinary domestic purposes, but for
almost all technical uses to which sugar is put, it is as suitable as
the other two kinds of sugar. Its use, however, is handicapped by

292 SCIENCE AND PRACTICE OF DAIRYING.

its high price, which is due to the fact that it is only found in the
milk of mammals. It may be described as of rare occurrence in
nature; furthermore, it is only obtained from one mammal, namely,
from the milk of the cow, while on the other hand the raw material
for the manufacture of cane- and beetroot-sugar is very abundant.
Milk - sugar differs from cane and beetroot, as has already been
pointed out, chiefly by its much weaker sweetening power, and by
the fact that it is much less soluble in water than the other forms
of sugar, and forms saturated solutions which are not of the nature
of syrups, but are of a limpid consistency. These properties render
it very valuable for many purposes, especially for medicinal use.
It is used in medicine in the preparation of homoeopathic medicines,
for the purpose of diluting saccharine or powerfully acting drugs,
which have to be taken only in very small quantities, and also as
an addition to milk to be employed for the feeding of children
during the period of infancy. It has further been used for the
purpose of adulterating wine, and in certain purely technical arts.
On the whole, its use is comparatively limited, and can scarcely be
expected to be much extended. In the ordinary method of the
manufacture of milk into cheese, about 85 per cent of the entire
amount of the milk-sugar in the milk passes into the whey, with
the result that this latter contains on an average about 4"8 per cent
of milk-sugar.

Whey is the raw material from which milk-sugar is prepared.
Its condition, the lactic and acetic acids it contains, its albu-
minoids and mineral salts, and especially the alkali salts, increase
the difficulty of separating the milk-sugar. By the action of the
acids and the mineral salts, a portion of the milk-sugar is carried
away in the process of crystallization, and is thus lost. By the
addition of milk of lime the acids may be fixed, but the alkali salts
cannot be removed, and what is gained on the one hand is lost on
the other, by the formation of a compound of sugar and chalk.
And since the albuminoids which are present impede the crystalli-
zation of the sugar, even under the most favourable conditions, it is
not easy to obtain more than 66 per cent of the milk-sugar in the
whey. In the preparation of beetroot -sugar, 80 per cent of that
originally present in the raw material is easily obtained, while in
the preparation of cane-sugar a still larger yield is obtained. Thus,
owing to the fact that only a comparatively small portion of saleable
sugar can be recovered from the milk-sugar in the whey, and that

SnLK-SUGAR. 293

the whey on an average contains only about 48 per cent of milk-
sugar, while the sap of beet-root and sugar-cane contain more than
three times as much, the conditions for the manufacture are not of
such a nature as to be profitable; and, in addition to all this, the
limited uses of milk-sugar have to be taken into account. The
experience of the last twenty years has shown that the preparation
of milk-sugar from whey is not remunerative. It can only become
so if the business is carried out on a large scale.

In the preparation of milk-sugar on a large scale, the whey is eva-
porated down in vacuum pans, either to the condition of a thin syrup,
and then the sugar is allowed to crystallize out, or it is evaporated
down till the sugar crystals separate out by means of centrifugal force
from the syrup. The residue is utilized for the feeding of SAvine, since it
is not worth while to recover, by osmosis, the sugar still remaining in the
syi-up.

In order to refine the raw milk-sugar, it is first of all dissolved in
Avater, the solution is then filtered, and to the filtrate there are added, for
every kilogram of sugar, three grams of sulphate of alumina and five giams
of milk of lime. The solution is then boiled for five minutes and filtered,
and in order to remove the colour the filtrate is passed through carbon
filters. The crystallization of the sugar from the solution is promoted by
the addition of alcohol. The sugar is obtained in the form of crystallized
sticks, which are obtained by^ suspending threads of cotton wool or thin
sticks of wood in the solution, of sugar, and allowing the crystals to de-
posit round them, and is knoAvn as grape-sugar, in distinction to the sugar
Avhich is obtained in the form of plates by alloA\dng it to crystallize on
the bottom and sides of the vessel, which is known as flat-sugar. The
grape-sugar is purer than the flat-sugar. By repeated crystallizations
milk-sugar may be obtained in transparent glassy crystals, which possess
a retail value per kilogram of from 2-2 to 3*3 marks.

Before 1880 there was only one dairy factor}^ in Germany in Avhich
milk-sugar Avas made, but since then SAvitzerland supplies all the milk-
sugar used. It is prepared in the summer-time in the Canton of Berne,
Avhere neither the labour nor the fuel are especially expensive, by simply
e\'aporating the Avhey in cheese-kettles over an open fire. It is obtained in
the form of a gi'itty material, the so-called "sugar sand", Avhich is of a light
yelloAvish gray colour, and is comparatively impure. The eA'aporation
of 500 kilograms of Avhey occupies about 24 hours. This sugar sand is
bought by merchants and refined. In the year 1876 it Avas valued in the
Alps at -6 to -7 marks per kilogram, Avhile the value of grape-sugar and
.flat-sugar, according to purity, Aaried from ri2 to 1"3 marks per kilogram.

(1)

(2)

. 5-67

9-48

. 92-49

86-28

. MO

3-90

. -74

•33

100-00

99-99

294 SCIENCE AND PRACTICE OF DAIRYING.

Two samples of milk-sugar analysed by Dr. Gerber had the following
compositions : —

Water and volatile substances,

Milk-sugar, ...

Albuminoids,

Ash,

Sample (1) came from East Russia, and sample (2) from Marba, in
Canton Lucerne, Switzerland. Nothing is known with regard to attempts
made to adulterate milk-sugar. The percentage of pure sugar, in the
commercial sugar, is determined in the same way as in ordinary sugar.

138. Bye-products of Milk of Minor Importance. — Among the
different foods prepared from milk, the following, only known in
the East, may be mentioned: —

Keschk, small rods or balls, obtained by thickening very sour
butter-milk, and used in Asia, from Syria to Afghanistan, or Turkis-
tan, as an addition to herb porridge. The very dark-coloured
residue remaining, after the making of keschk, possesses a sour and
salt-like flavour, and is also used as an article of food, and is called
karagrut. If milk be coagulated by the addition of keschk, a sub-
stance called jaurt is obtained, which, when mixed with salt and
water, constitutes a favourite dish. We have already discussed in
§ 126 the preparation of effervescing beverages from whey, and
the hitherto unsuccessful attempts to prepare alcohol or vinegar
on a large scale from whey.

The application of liquid milk products and caseous matter in
certain trades, depend, on the one hand, on the fact that solutions of
casein, when dried, form a hard, horny, elastic mass, not readily
soluble in water, and, on the other hand, on the fact that casein
forms, with the oxides and salts of the metals of the calcium group,
a cement-like compound, insoluble in water.

It has been known for centuries that the peeling off of white-
wash may be prevented if butter-milk or whey be substituted for
the milk of lime.

For painting wood which it is desired to protect from the
influence of the weather, there should be used either a cement which
has been stirred to a thick paste, or a mixture of curd, linseed oil,

BYE-PRODUCTS OF MILK OF MINOR IMPORTANCE. 295

chalk, and water. Emulsions of olive oil in milk are used in the
manufacture of wool, for the purpose of adding fat to the wool.

Lactarine, or casein gum, is almost pure casein specially prepared,
which, when dissolved in ammonia, is used for fixing and thickening
colours in calico printing. Casein lime, or casein cement, is made
out of skim-milk cheese very poor in fat. It is very useful, and
is much used in carpentry. The cheese is cut into small morsels,
quickly dried, and ground into a line powder, which is mixed with
20 per cent of burnt chalk. If it be desired to keep it for some
time, it must be put into closed vessels and mixed intimately with
not more than 1 per cent of camphor. Casein lime comes in fair
quantities from Switzerland.

Lactite, or milk ivory, is a hard horny substance prepared from
casein. Attempts are at present being made to introduce it for
technical purposes. The author has a black button made from this
substance, which is externally indistinguishable from a common
bone button. Whether this is a lucrative application of casein, and
whether the new substance is able to replace horn or bone, remains
to be seen.

CHAPTER VII.

THE ECONOMIC ASPECTS OF DAIRYING.

139. The Sale of Milk for Direct Consumpt. — Among the ordinary
methods of utilizing milk -svliich have been practised for any length
of time, it may be said that the sale of milk for direct consumpt is
the most lucrative. This method of distributing milk is widely
practised wherever a dense population causes a large demand for
fresh milk. The price of a litre of milk is, under these circumstances,
always at least so high that it approximates to the average price
obtained by manufacturing (churning) the milk in the country. It
increases, of course, as the expenses in its distribution increase. It
is only when the development of the conditions of trading does not
keep pace with the growing demand, that the price of milk can
exceed the above limit. According as the supply is lightened, facili-
tated, and rendered cheaper, so is the field extended for which the
sale of fresh milk is the proper and economical method of milk
distribution. The question then presents itself to farmers who
have churned their milk, whether they should still adhere to this
m.ethod; or whether they should give it up and sell the milk. The
decision of this question is very easy for anyone who has a well-
kept farm. He has simply to calculate the highest limit of value
which, under the most favourable circumstances, he can obtain per
kilogram of milk, calculated on the basis of its composition. This
is furnished him by an examination of his accounts, as well as by a
statement of the total expenses which he may incur in its distri-
bution, and then he may compare these sums with the market value
of a kilogram of milk. The disposal of milk by selling it in a fresh
condition necessitates only a slight expense in utensils, and is
accompanied by little risk. It also affects the management of a
farm very little, so long as the consumer is quite indifferent to the
quantity of fat and total solids contained in the milk, and it keeps
the capital of the farm circulating quickly and regularly through-
out the whole year. All that is necessary is to regulate the time
of the calving of the cows to suit the trade, and to see that the
necessary food is supplied at each season of the year, so that a
uniform quantity of milk be provided throughout the whole year.

UTILIZATION OF MILK BY MAKING IT INTO BUTTER. 297

This method of utilizing milk is as well suited for the occupant of
a small farm as of a large, with the exception that the latter has
this advantage over the former, that he can distribute his larger
amount of milk over wider areas at the same expense per gallon.
This mode of milk disposal is not well suited where the rearing of
calves is practised. It is also to be noted that where the milk is
sold off the farm, all the mineral constituents of it are lost. An
increased price can under certain circumstances be obtained for
milk by sterilizing it, or by exercising that amount of care which
is necessary to fit it for sale in milk-curing establishments or in
the rearing of children. If this be done, however, a considerable
increase of expense is incurred in plant.

140. Utilization of Milk by making it into Butter. — On dairy-
farms, where the sale of fresh milk is, for economical reasons,
impossible, the attempt is generally made to utilize milk by con-
verting it into butter, to a far greater extent, than by converting
it into cheese. The reason of this is chiefly, but not entirely, due to
the fact that butter is the most largely required milk product. It
is also to be considered, that the variation in the percentage of
bacteria in the milk, due to the utilization of the most widely
different kinds of food, does not affect the preparation of butter —
a fact which in earlier times was rarely noticed, and which at
present can be rendered absolutely of no effect by Pasteurizing the
cream, so that the preparation of butter is, to a large extent, inde-
pendent of certain changes which affect the preparation of fat
cheese. Finally, it must not be overlooked that the preparation of
butter demands more care and attention than peculiar skill. The
above-mentioned facts cause the preparation of butter to be a very
widely practised art.

The utilization of milk by manufacturing it into butter requires
a larger expenditure in plant than the sale of milk; it does not obtain
so quick or so regular a return of the capital employed. In dairy-
farming, this method for the disposal of milk is not so popular, since
it requires more attention to the feeding of milk cows, more time
and knowledge for its supervision, more human labour, and lastly,
special arrangements for disposing of the bye-products. By the
sale of the butter practically no mineral constituents are removed
from the soil of the farm. The keeping qualities and the large
demand for butter offer many commercial advantages. For one
thing, the product may be temporarily stopped if the times are

298 SCIENCE AND PRACTICE OF DAIRYING.

unfavourable. For another thing, more distant markets may be
sought. Where butter is prepared, the rearing or fattening of calves
or of swine is carried on, or, less frequently, the preparation of
skim-milk, when all bye-products, both of the butter and the skim-
milk, are utilized for feeding swine. It may be calculated that
every four cows keep, on an average, one old and one young pig,
and every four to five cows a breeding sow.

The manufacture of butter may be effected on a small scale as
well as on a large scale, but is more lucrative on the latter scale.
The prices of the butter market show that butter made in large
dairies is, on an average, better than that prepared in small dairies.
On small farms it is not convenient to churn every day.

141. The Utilization of Milk by converting it into Fat Cheese.—
The fact that the practice of making fatty cheeses is less extensive
than the making of butter, is due to the fact that the former method
of utilizing milk is largely influenced, as has been pointed out, by
certain local conditions, as well as by the fact that the art of cheese-
making not merely requires aptitude and care, but involves reflection,
skill, and experience. The assertion that the practice of cheese-
making prevails in mountainous districts, and in districts thinly
populated, because cheese keeps better than butter, is by no means
correct. The conditions necessary for the successful manufacture of
fat cheeses do not admit of such perfunctory dismissal. Fatty soft
cheeses are almost always less easily kept and less in demand than
salt butter. Only certain kinds of fat hard cheeses are uncondi-
tionally superior to butter in this respect.

It may be regarded as beyond doubt that the ripening of cheese
is eflfected by bacteria. On the one hand, we know that the different
kinds of bacteria exercise different kinds of actions, and, on the other
hand, that certain kinds of cheeses are characterized by particular
properties. From this it may be inferred that the ripening of each
kind of cheese is dominated by a particular kind of bacteria. If
this is correct, it follows, further, that each kind of cheese will be
most successfully manufactured when the proportion of the kinds of
bacteria implicated in the manufacture of the cheese are present in
the right quantity. Since milk leaves the cow's udder free from
bacteria, it follows that nearly all the bacteria which lodge in it are
derived from dirt, which comes into it chiefly from cow dung. The
bacterial percentage in dung depends directly on that in the food,
and this is influenced indirectly by the manuring and by the different

UTILIZATION OF MILK BY CONVERTING IT INTO CHEESE. 299

kinds of food. In districts where manures of the most various
kinds are applied, and in which not only the kind of feeding but
also the condition of the fodder varies on different farms, and in the
course of a year even on the same farm, to a considerable extent,
the percentage of bacteria in the milk must be naturally subject to
great variation. If this is the case, the ripening of cheese, when
the method of treatment remains the same, cannot possibly be of a
uniform nature. The success of the cheese manufactures will be
more or less affected, if not entirely jeopardized. These conditions
are most active in the case of the preparation of the best hard fatty
cheeses, which ripen slowly. They have little effect, it would
appear, on fat soft cheeses, the ripening of which begins on the
surface and develops towards the centre, nor have they much effect
on skim-milk cheeses. In certain districts of Switzerland on the
one hand, and in Holland on the other, the conditions favourable
for the manufacture of fine fatty hard cheeses are especially favour-
able. In both countries the cows feed througli the entire summer
on excellent pastures, during winter-time on good hay. In both
countries the similarity of the feeding of the cattle, and the treat-
ment of natural pastures, effects a uniformit}^ in the bacteriological
condition of the milk, which is scarcely found elsewhere in Europe.
Nevertheless, these two countries are not exactly on the same level,
Switzerland, with its high-lying Alpine pastures, coming before
Holland. The deep and moist marshes are undoubtedly richer in
bacteria than the Alpine ones. We have already seen that in
Holland, in the preparation of the much-prized kinds of cheeses,
the percentage of bacteria in the milk has to be influenced b}^ the
addition of ropy whey to the milk. Although Emmenthaler cheeses
on the one hand, and Gouda on the other, are no longer, as was
formerly the case, only made in summer, but also in winter, and
although they are no longer exclusively manufactured in Switzer-
land and in Holland but also in other countries, it still remains the
fact that summer cheese is superior to winter cheese, and cheeses
made in those countries with which the manufacture of the cheese
has been long associated are better and finer than those made in
other countries.

Good butter finds a ready market everywhere, but the different
kinds of fat cheeses are not equally liked in different localities. It is,
therefore, of the highest importance in the manufacture of cheese to
ascertain exactly what the taste for cheese is, and only to prepare

300 SCIENCE AND PRACTICE OF DAIRYING.

cheeses which are in demand, and which are thus sure of a market.
It must also, however, be clearly understood that it is necessary to
make cheeses of a good quality, and not to think that this is of easy
accomplishment. For this purpose, in deciding the question of
whether it is more advantageous to make butter or cheese of this or
that kind of different fat cheeses, it is also necessary to consider
along with this general question, others connected with the economic
side of the question, and especially the local and natural conditions
influencing the exact bacteriological condition of the milk, which
produce in different districts and countries the predominant flavour.
It is also necessary to consider the absence or presence among the
people of a cultivated taste for cheese.

If the trade in fatty cheeses requires less capital involved in
plant than that in butter, it nevertheless requires a large circulating
cajjital, as it is accompanied by more risk and the money is returned
more slowly. For this reason, however, it is suited for a wider
utilization of milk, since the manufacture can be stopped at any
time without disadvantage, and the preparation of butter and the
manufacture of skim-milk cheese can be substituted. When cheeses
are sold off the farm, a not inconsiderable portion of mineral salts,
consisting chiefly of calcium phosphate, is removed. If all the milk
in a dairy be made into cheese, the value of the whey which is
thus obtained may be estimated at one pig for seven to eight cows.

The inhabitants of Switzerland, who have for many hundreds of years
produced an amount of milk in large excess of that which they can them-
selves consume, were early forced to utilize this excess by making it into
cheese, since they could find, neither in their own country or in the neigh-
bouring ones, the necessary market for the large quantities of butter which
they manufactured therefrom. Hitherto — as, indeed, it is at present — the
demand for butter in Switzerland and in South Germany has been much
less than in North Germany, which is partly due to climatic conditions,
and partly to the method in which bread-fruits have been used. Helped by
the very favourable conditions which exist for the manufacture of the fatty
cheeses, they have brought the manufacture of what is the finest and most
highly-prized cheese, namely, the Emmenthaler, to great perfection.

In the manufacture of the finest soft cheeses, of different kinds, the
French nation are unexcelled. The preparation of French table cheeses
demands a great deal of care, a great deal of trouble, and attention to a
large number of details; while skill is also required in a minor degree.
It is more the work of women than of men, and the manufacture is not

THE UTILIZATION OF MILK IN DIFFERENT COUNTRIES. 301

only conducted in many small agricultural districts, but also, on account
of the demand for this kind of cheese, it is made in factories on a large
scale.

Other kinds of cheese of a less fine flavour are the Dutch and the
English fatty and hard cheeses, the Edam and Gouda, made in Holland,
in the marsh districts, and the Cheshire and Cheddar, which are made
in England, in the districts specially suited for the manufacture of the
cheese, chiefly in small and middle-sized dairies. Cheddar cheese is also
made in large qi;antities in the United States. This kind of cheese is
not only popular in its mother country, but in the colonies of Holland
and England across the seas. The demand in the colonies is so great that
the English production is far from adequate to the demand, and these
cheeses are chiefly imported from North America. Owing to the condi-
tions prevailing in North America, the fat cheeses are made on a large
scale. As the manufacture of cheese in North America is nowhere carried
on under especially favourable natural conditions, and is therefore uncer-
tain in its result, the practice has been long tried of alloAving the milk to
become sour in the milk-vat, in order to increase the percentage of bacteria
in the cheese, and thus to favour its ripening.

142. The Utilization of Milk in Different Countries. — Wherever
cattle are kept, the rearing of calves, which only requires, compara-
tively speaking, a small portion of the milk, is carried on in
addition to the other uses to which milk is put. The rearing of
calves requires a large amount of capital, which is only slowly
turned over, and as it involves much care and skill, it is better
suited for large than for small farms. In the husbandry of districts
of flat land in which milk-cows are kept in restricted numbers only,
the rearing of calves is carried on with success, in addition to the
manufacture of butter. On the other hand, in countries which are
well suited for the keeping of cattle, the rearing of calves, in addi-
tion to other methods for the utilization of milk, is practised, and
this custom, from an economic point of view, justifies itself. In
countries wdiere there is no lack of valuable cattle suitable for the
purpose of rearing, young cattle are always reared. Here and there,
however, in isolated districts, highly favourable conditions obtain for
utilizing milk, and it would be a great economic mistake not to take
advantage of them. The result is, that in all countries specially
adapted for live stock, it is not possible to draw sharply-defined dis-
tricts suited for different methods of utilization, and it is interesting
to note in this connection that, on the whole, a higher return is

302 SCIENCE AND PRACTICE OF DAIRYING.

obtained by natural variation than would be the case if the entire
population were set down to one branch of dairying. We find in
Switzerland, that in addition to the rearing of live stock, and to the
manufacture of butter carried out on a small scale, on the hill lands
where rich pasture exists, an actively conducted and very remu-
nerative manufacture of cheese is carried on; and in Holland, in
addition to the rearing of cah^es, and a considerable manufacture of
butter, we also find that not only is an excellent trade in the manu-
facture of cheeses carried on, but also in the fattening of animals on
pastures. Similar conditions are found in the province of Schleswig-
Holstein, in its different parts. In any country in which the
diflferent branches of dairying are found existing, developed to a
natural degree, one is in a position, according to the state of the
markets, to extend or to limit now the one or now the other branch
of the dairying, so as to make the receipts at all times as high as
possible.

143. Calculations for the Different Methods of Milk Utilization. —
Under certain definite suppositions, and provided that on an average
1000 kilos, of milk, containing 3"3 per cent of fat, are at disposal
daily, the following is the value of a kilo, expressed in pfennig,
and also the expense of treating a kilo. : —

Nett Proceeds. Expenses.

(1) Sale of milk for direct coiisumpt, ... 15*52 4

(2) Fattening of calves with milk, ... ... 10 3

(3) Manufacture of whole-milk soft cheese, 12'75 1*5

(4) Preparation of Avhole-milk hard cheese, 11 "71 1*25

(5) Deep setting system, and the manufacture

of butter and half -fat soft cheeses, .. . 10'25 1'25

(6) Deep setting system, and the manufacture

of half-fat hard cheeses, lO'Ol 1*25

(7) Treatment with centrifugal machine, and

the manufacture of butter and skim-
milk brick-shaped cheeses, ... ... 9"26 2*3

(8) Treatment Avith centrifugal machine, and

manufacture of butter and skim-milk

hard cheeses, .. . ... ... ... 8*16 2*30

(9) Treatment by centrifugal separator, and

the fattening of calves with skim-milk, 8 '7 2 2

(10) Treatment with centrifugal separator,

and feeding of swine with skim-milk, 7*89 2

(11) Deep setting system, the manufacture of

CALCULATION FOR DIFFERENT METHODS OF MILK UTILIZATION. 303

Nett Proceeds. Expenses.

butter and skim-milk brick-shaped

cheeses, ... ... ... ... 9"73 2

(12) Deep setting system, the manufacture of

butter and skim-milk round cheeses, 10*04 2

(13) Deep setting system, manufacture of

butter, and feeding of calves with

skim-milk, ... ... ... ... 8"4:6 1*7

(14) Churning of milk, a.nd manufacture of

sour-milk cheeses, ... ... ... 9*69 2

(15) Churning of milk, and the manufacture

of sour curd, ... ... ... ... 9*03 1

(16) Churning of milk, and feeding of pigs

with butter-milk, 7*79 1

Of the nett proceeds realized, the following shows the amounts obtained
by the various products: —

In the case of the manu-
facture of whole-milk
cheeses, ... ... by cheese, 80 to 94 %, on an average 87 %.

by bye-products, 20 ,, 6 ,, „ 13 „

In the case of the pre-
paration of butter and

half-fatty cheeses, ... by butter, 22 „ 24 ,, „ 23 „

by cheese, 67 ,, 69 „ „ 68 „

by bye-products, 8,, 10,, „ 9,,

In the case of the pre-
paration of butter and

skim-milk cheeses, ... by butter, 58 „ 79 „ „ 69 „

by cheese, 13 „ 34 „ „ 24 „

by bye-products, 5 „ 9 „ „ 7 „

In the case of the pre-
paration of butter,
along with the feeding

of calves and pigs, ... by butter, 68 ,, 83 „ „ 76 „

by bye-products, 17 „ 32 „ „ 24 ,,

According as one makes either half-fat or skim-milk cheeses, or
carries on the fattening of animals in addition to the manufacture of
butter, the proceeds obtained from butter in the above-mentioned
examples, which furnish data for the calculation, will amount to 23,
69, or 76 per cent. As the price obtained for milk depends upon
the prices of its products, and as the prices of butter and cheese, as
well as bacon and veal, vary in the course of time within wide limits,

304 SCIENCE AND PRACTICE OF DAIRYING.

it is obvious that the value of a kilo, of milk in the various methods
of utilization is not to be found in the individual figures themselves,
but rather in the proportion they bear to one another.

To illustrate the foregoing statements, we may take an example or
two: —

(1) Sale of Milk for Direct Consumption. — If a litre of milk can be sold
for 20 pfennig, and the cost connected with the sale amounts to 4 pfennig,
then the kilo, of milk will realize 15-52, and the litre 16 pfennig.

The calculation of the weight of the milk from its measure is here
based, as it is in all the following cases, on the assumption that the specific
gravity of the milk, at 15° C, is 1-0315.

(2) Manufacture of Fatty Soft Cheeses. — There are so-called Eemoudou
cheeses, which are sold in a ripe condition at 1"2 marks per kilo. If the
cheese loses in the store, before it is sold, 30 per cent of its Aveight, the
value of the fresh cheese can only be placed at -84 marks per kilo.

100 kilos, of milk yield —

Cheese, ... 16 kilos @ -84 marks = 13-44 marks.

Whey, 81 „ „ -01 „ = -81 „

Loss, ... 3 ,,

100 kilos. 14-25 marks.

■ ' Expenses, 1-50 „

12-75 marks

1 kilo, of milk thus produces 12-75 pfennig, and a litre 13-14 pfennig.

(3) Prejyaration of Fatty Hard Cheeses. — Fatty hard cheeses, prepared in
the Swiss method, possess, in a ripe condition, a market value of 1 -4 marks
per kilo. If the cheese lose in the store before its sale 15 per cent of its
weight, the value of the fresh cheese can only be put at 1-19 marks.

100 kilos, of milk produce —

Cheese, ... 9-00 kilos. @ 1 -19 marks =
Whey butter, -75 „ „ 1-60 „

Butter-milk, 1-20 „ „ -02 ,^ -

Ziger cheese, 2-50 „ ,, '16 „ =

Whey, ... 84-55 „ „ -0075,, =

Loss, ... 2-00 „

100-00 kilos. Expenses,

10-71 marks.

1-20

))

•02

•40

•63

))

12-96

marks.

1-25

11-71

marks.

1 kilo, of milk produces 11*71 pfennig, and the litre 12-07 pfennig.

KEEPING OF BOOKS.

305

(4) Ice Treatment — Preparation of Butter and Half-fat Hard Cheeses. —
Half-fat hard cheeses, made according to the Swiss method from evening
milk which had been creamed after treatment with ice, and of whole
morning milk, the whole being treated after standing for twelve hours,
possess a market value when ripe of 1 mark per kilo. If the cheese lose
12 per cent of its weight in the store, the fresh cheese can only be valued
at "88 marks per kilo.

100 kilos, of milk produce—

Cheese,

8-50 kilos. @ -88 marks =

7-48 marks.

Butter,

1-30 „

„ 2-10 „ =

2-73 „

Butter-milk, . .

2-60 „

., -02 „ =

•05 „

Ziger cheese.

2-40 „

„ -16 „ ==

•38 „

Whey,

83-20 „

„ -0075

•62 „

Loss,

2-00

Expenses, =

100-00 kilos.

11-26 marks.
1-25 „

10-01 marks.

1 kilo, of milk fetches 10-01 pfennig, and 1 litre 10-3 pfennig.

In this case 1*1 kilo, of cream butter, and in addition -2 kilos, of whey
butter, that is, a total of 1-30 kilos, of butter, are obtained. If cream and
the whey cream be together made into butter, a butter of inferior quality
is obtained of which the kilo, can no longer be valued at 2"2 marks, but
only at 2-1 marks.

According to numerous carefully collected data, the cost of collecting
200 cart-loads of ice of 30 cwts. weight, may be put at 375 marks. If the
ice-house necessary for keeping this ice be estimated as costing 2000 marks,
and 15 per cent of this amount be allowed yearly for interest and deprecia-
tion, that is, 300 marks per annum, the total. cost for ice may be stated at
675 marks. If the 300,000 kilos, of ice in the course of time be diminished
one-half, and if there be used, on an average, in cooling 1 kilo, of milk,
-5 kilos, of ice, the amount of milk cooled by the ice will amount to
300,000 kilos., and the cost will amount to -225 pfennig per kilo, of milk-
This calculation, which for the sake of simplicity may be roughly put at
-3, is included in the 1-25 pfennig which has been included as the cost of
treatment per kilo, of milk.

144. Keeping of Books. — Dairy accounts are kept practically in
all dairies in Germany, in some cases in an elaborate, in others in a
perfunctory manner. In almost no case are none kept. As each
business becomes extended and developed, the more obligatory does

(M175) XJ

306

SCIENCE AND PRACTICE OF DAIRYING.

the systematic keeping of books become, and in the case of public
companies, according to the law of May 1st, 1859, special books,
which have to be audited at least every two years by an impartial
auditor, must be carefully kept. The proper manner of keeping
books for dairy purposes is easily learned.

Fig. 83.— Machine for Weighing Milk.

In a good system of book-keeping, not merely milk, but also all
milk bye-products, should be entered, not according to volume, but
according to weight (figs. 83 and 84). The ^ kilo, or pound has
been chosen as the unit of weight in all technical calculations in
dairying, since the kilo, is too large for this purpose.

In book-keeping, an exactly accurate account of all the items
connected with the obtaining and treating of milk must be noted.

KEEPING OF BOOKS.

307

In the first place, a record should be kept of the annual yield of
milk per cow, its average percentage of fat, and the annual yield of
butter, in order to form a basis for the economic valuation of the
individual cows. Further, the books must exactly indicate how
much of the milk supplied to the dairy is used, and how much is

Fig. S4.— Macliiiie for Weigliing Milk.

sold; how much is treated, and what amount of bye-products are
obtained; what loss the bye-products involve, and what value they
fetch. In addition, calculations should be made with regard to all
the bye-products, by which the yield, both with regard to quality
and quantity, as well as the amount of working expenses, is influ-
enced. Records should also be kept of the temperature of the milk,
cream, and skim-milk; and, in the case of cream-raising, particulars

308 SCIENCE AND PRACTICE OF DAIRYING.

as to the entire course of creaming should be noted. In cheese-
making, particulars should be noted with regard to the use of rennet
and cheese colours, the duration of the thickening period, the treat-
ment of the curd, and the temperature and the relative moisture in
the cheese store-room. Where ice is used for different purposes,
careful records should be kept, and particulars as to the weather
and other conditions, which do not admit of enumeration in this
place, should also be taken.

For the purpose of determining the milk record of the year, milk
registers may be used, in which the weekly results of the testing of samples
should be entered. The percentage of fat in the milk may be determined
once every week.

If the figures with regard to the treatment of milk are perfectly I'e-
corded, it is possible to determine daily, weekly, monthly, or yearly the
success of the ti-eatment of milk, either on an average or in individual
cases.

For example, if one finds that 100 kilos, yield —

Cream, ... ... ... ... 16"68

Skim-milk, 82-75

Loss, ... ... ... '57

100-00

by dividing 16-68 into 100, the result will be 5-995, a number which
indicates how many parts by weight of milk correspond to 1 part by
weight of cream. This number is used for calculating the yield of butter
from milk by weight, in which the cream coming from the milk to be
treated is not all made into butter. If, for example, 10 kilos, is all that
is used of the entire quantity of cream obtained, the quantity of milk
treated must be diminished by 10 x 5-995, which equals 59-95, in order
to obtain the quantity of milk used to get the amount of butter.
For example, it is found that 100 kilos, of cream yield —

Butter, 20-38

Butter-milk, 77-70

Loss 1-92

100-00

To these, 100 parts by weight of cream, as we know, correspond 599-5
parts by weight of milk, according to which we find that for every part by

KEEPING OF BOOKS.

309

2 9 '41 parts by weight of milk correspond, or

599-5
weight of butter 20^

for every 100 parts by weight of milk -i^ = 3'4: parts by weight of

butter correspond. If the skim -milk be made into skim-milk round
cheeses, Ave further knoAV, for example, that 100 kilos, of skim-milk yield
on an average —

Cheese, 7-96

Whey, 89-61

Loss, 2-43

100-00 kilos.

From this we find that for the preparation of one part by Aveight of fresh
cheese, ^Tgg^ 12-56 parts by weight of skim-milk are required. From all

the above-mentioned figures we finally discover that 100 kilos, of milk on
an average yield—

f Butter, 3-40

Cream, 16-68 kilos, j Butter-milk,... 12-96

[ Loss, -32

f Cheese, 6 59

Skim-milk, ... 82-75 „ i Whey, 74-15

I Loss, 2-01

Loss, -57 „ Loss, -57

100-00 kilo.s. 100-00 kilos.

The total loss, therefore, in treating 100 kilos, of milk amounts to 2-90
kilos. If the gross value of the individual products and bye-products be
known, it is easy to calculate the gross value of a kilo, of milk from this.
In the preparation of fat cheeses, as, for example, in the preparation

of Emmenthaler, it is fovind on an

Cheese,
AVhey butter,
Butter-milk, ...
Ziger cheese,
Whey,

Loss, ...

average that 100 kilos of milk yield-

9-00

-75

1-30

2-50

84-60

1-95

100-00 kilos.

For every one part by weight of fresh cheese, there is accordingly required
—- = 11-11 parts by weight of milk.

310 SCIENCE AND PRACTICE OF DAIRYING.

The actual yield of butter obtained may l)e easily tested, as soon as the
average percentage of fat of the milk treated is known, by means of a for-
mula, to see whether it may be regarded as satisfactory or not. If the
quantity of butter-milk obtained from 100 kilos, of milk be indicated by
the letter B, and the percentage of fat of the milk, the skim-milk, and the
butter by/, /\ and F, and the quantity of cream yielded per 100 parts by
Aveight by the letter R, and the yield of butter by the letter A, the follow-
ing formula will be obtained: — •

1b4(/-/'x'^^')-

Thus, if to A, F, and P the values of 97 per cent, 84 per cent, and "25
per cent be given, which may be regarded as what should be easily obtained
in practice by careful work, and which, therefore, should be regarded as
satisfactory, and to R the value of 15 per cent, we find the following: —

(I.) B = 1-155 x/- 0-245.

For / will be found .3-30 per cent, and for B 3-57 per cent; that is, one
must obtain from 100 kilos, of milk 3-57 kilos, of butter. If, then, the
calculated quantity of butter is found to be more than that actually obtained
by '1 or more per cent, there is a mistake made somewhere, either in the
creaming or in the churning. In order to discover where this mistake is,
the percentage of fat in the skim-milk and in the butter-milk must be
determined, so that the correct measure obtained in proper working should
not be exceeded.

If the common formula (1) for/ be worked out, the result is as follows : —

(n.)/=!^ + /''^^-

If, again, the values for A, F, P, and R be again the same, as given above,
the following will be the result: —

(II.) /=0-866xB + 0-2125.

From this formula, provided the work be carefully and properly carried
out, it is possible to calculate, with approximate accuracy, the average per-
centage of fat in the milk, when the yield of butter is known.

Finally, if we indicate the percentage of fat in the cream by the letter
/^, the following formula will be obtained : —

100 (100 -R)

(III.) P - -^ X/-/1 — R— , or

00 xF
AxR

«_100xF -p..

PAYMENT OF MILK ACCORDING TO WEIC4HT AND COMPOSITION. 311

and if the above-mentioned values be given to A, F, /\ and E, the
i^esult is as follow : —

(III.) /- = 6-667 x/- 1-4167, or
/"- = 5-773 X B.

For calculating B from / or /- : —

B = 1-15.5 x/- -245, and B= -1732 xf-.

For calculating / from B or /- : —

/= -886 X B + -2125, and /= -15 x/- + -2125.

For calculating /- from / or B : —

f = 6-667 x/- 1-4167 and /- = 5-773 B.

With the help of these formula?, it is possible to calculate from any one
of the magnitudes F, P, A, and R, what the rest are.

145. The Payment of Milk according to Weight and Composition. —
Milk which is used for direct consumpt is sold at present, as is well
known, according to measure, and not according to composition.
Indeed, it is sold without any reference to its composition — a fact
which is in the interest of the seller, but not in that of the pur-
chaser. On the other hand, milk which is destined to be worked into
milk products has been sold since about 1880 at so much per kilo-
gram, according to its composition. This arrangement has become,
from an economic point of view, all the more urgently desirable the
more the trade has improved, the keener the competition in the
production of butter and cheese has become, and the more convenient
the conditions are for the working of large quantities of milk. It
has only been adopted since the methods for the determination of
fat in milk have improved so much that the fat can be determined
in a short time, with all the accuracy that is required, without the
aid of a chemical balance.

The exact determination of the price of a kilogram of milk,
according to its composition, and the amount of substance it will
yield when converted into either of its bye-products, is very difficult,
and indeed hardly possible to calculate. The more accurately the
manufacture is conducted, the more trouble and expense has to be
incurred, and, when there is taken into account in this connection
economic considerations, one is forced to rest contented with obtain-
mg a good result without striving to reach the best possible.

312 SCIENCE AND PRACTICE OF DAIRYING.

The first consideration in determining the utilization value of
milk is an exact knowledge of its solids. It is scarcely of any-
practical value to obtain the composition of milk in all its constitu-
ents, since its value is almost entirely determined by its percentage
of fat and casein, and only to a slight extent by its mineral consti-
tuents. But even the determination of the caseous matter, in addition
to the fat, in order to estimate its value for the manufacture of fat
and skim -milk cheeses, is only of advantage in a few cases. It
involves far more than double the expense caused by the determina-
tion of the fat alone. At present, therefore, it is only customary
to obtain the percentage of fat in milk, and to calculate the value
from that.

Obviously, if the selling price is to be determined in the dairies
of the different suppliers of milk by the percentage composition of
the milk, it will be necessary to estimate daily the percentage of fat
in each consignment, since it is only by this method that the true
average percentage in the milk of the different suppliers for the
period for which payment is made can be determined. This in
practice, owing to the great expense involved, is at present scarcely
feasible. For this reason, it is only customary to examine the milk
of each customer several times in a month for its percentage of fat,
and to calculate from the figures thus obtained an average value,
Avhich obviously will not exactly agree with the true average value.
The of tener per month the investigations ai'e undertaken, the nearer
will the true average value be arrived at; and the frequency with
which they are made depends on the degree of approximation which
those interested deem desirable. A periodical examination of the
milk should be made not less than once a week.

If the amount of the average percentage of fat of the milk
obtained during the month from each supplier be known, as well as
the average percentage of fat in the whole quantity of milk worked
during the month, and if the question be how to fix a price for a
kilo, of milk from the different suppliers, and the monthly price to
be paid, several methods may be adopted, according as to whether,
as is the case in dairy companies, the question is as to the division
of a sum of money, or, as is the case with the dairy-farmer and the
owners of collecting dairies, the proper adjustment of the price to
be paid for the milk, to that of the price of the butter. We may
take the first case :

(1) Payment of Milk in Dairy Companies in which Fatty Cheeses

STRUCTURE AND ARRANGEMENT OF A LARGE DAIRY. 313

are made. — In the treatment of milk for the manufacture of fatty
cheeses, the idea is not excluded of taking the division of the pro-
ceeds according to the amount and the average percentage of fat of
the milk consignments. This procedure can be justified, in certain
cases at any rate, by the fact that the yield of cheese is not
dependent exclusively on the percentage of caseous matter in the
milk, and that it is not always proportional to the percentage of fat
in the milk; but that, for the most part, the milk richest in fat
yields the largest amount of cheese, and vice versa, and that in the
case of the percentage of caseous matter in the milk remaining the
same, the yield of cheese both in quality and quantity is greater,
the greater the percentage of fat. Indeed, there are kinds of cheeses
which turn out best if the amount of fat in proportion to caseous
matter does not exceed a certain amount, and in the preparation of
which, therefore, milk very rich in fat is scarcely much more valu-
able than milk of an average percentage of fat. In this case, it may
be doubted wdiether perchance a division of the proceeds simply
according to the quantity of the milk supplied by the individual
shareholders would not be best. The author is not aware whether
payment of milk by weight and composition has been introduced
into dairy companies in which only fatty cheeses are made.

In no case have reliable experiments, with regard to the influence
which a change in the composition of milk exercises on the yield of
fatty cheeses of different kinds, been made, and up to the present
time data are not available which permit of the further theoretical
consideration of the question.

(2) Payment of Milk in Dairy Companies ivhich have a Limited
Trade. — By a limited trade we mean the case where the milk which
is delivered is made into butter, and where all the bye-products in
varying amount are sent to the shareholders. By this method it
was formerly attempted to divide the monthly proceeds, according
to the amount of milk, and the average percentage of fat of the
milk consignments.

146. Structure and Arrangement of a Large Dairy. — During the
last fifteen years, in the course of which a large number of dairy
companies and extensive agricultural enterprises have sprung into
existence, the arrangement of dairies in our several districts has
been materially improved. Not only has the necessity been demon-
strated for providing all these requirements w^hich have shown
themselves in course of time to be important, but the opportunity

314 SCIENCE AND PRACTICE OF DAIRYING.

has been found to collect the necessary experience for carrying this
out in a suitable manner. It is now recognized that every pi'operly-
equipped dairy should possess an open healthy site, should be supplied
with good and pure water, and with ice apparatus, that its rooms
should have a flooring impervious to water, and that all w-aste
water should find easy exit. It is also necessary that the individual
rooms should be easily heated and aired when desired, and should
be supplied throughout with pipe connections supplying always
steam, or cold or hot water, and that there should both be a count-
ing-house, and a laboratory for the examination of the milk. A
further requirement is, that the individual rooms should not merely
be of a proper size, with regard to area and cubic capacity, but
should also be arranged in such a way that the treatment of the
milk can be carried on in the simplest possible manner, and that in
the preparation of the chief products, unfavourable influences should
not make themselves apparent. Finally, it is desirable that the
milk delivered, as well as the bye-products produced by its treatment,
should be dealt with by the assistance of gravity or other natural
forces on the place of delivery, and that manual labour should be
employed in their manufacture to as slight an extent as possible.

Figure 85 shows the method of arrangement of a modern farm, fitted
with machinery for utilizing a Danish centrifugal separator. From the
part (A) the milk is borne in cans (B) to the weighing-machine (C),
into the receiver of which it is poured. After it is weighed, the milk
flows first into the collecting-vat (D), and then through the tube (d)
and the warmer (E) into the separator (F). The cream then goes into
the ascending tube (G) into the scum-collector (H), flows through the
Pasteurizing apparatus (I) and over the cooler (J), and through the tin
gutter {j) into the cream-vat (K). The skim-milk is conducted through
the second ascending tube (L), and from there into the open gutter {I) and
then into the scum-collector (M), and through the Pasteurizing apparatus
(N) and over the cooler (0), and into the collecting-vat for skim-milk (P).
From the vat (P) the skim-milk is filled into the skim-milk cans (R)
standing on the balance (S), and then it is furnished again to the milk
suppliers. If the skim-milk be made into cheese, it is permitted to run
from the gutter (I) into the cheese-vat.

STRUCTURE AND ARRANGEMENT OF A LARGE DAIRY. 315

CHAPTER VIII.

MARGARINE AND MARGARINE CHEESE.

147. Margarine. — The manufacture of margarine as at present
carried on has as little to do with dairying as the manufacture of
margarine cheese. It is, however, desirable to say a few words on
its nature, as both these products enter into competition with dairy
products, and because the fraud connected with the trade in mar-
garine, wliich is growing in extent every year, and for the purpose of
checking which special legislation has become necessary, not merely
affects the dairying industry, but the whole agricultural industry.

Before the year 1887, margarine was universally known both
in Germany and in Austria as butterine. The preparation of
margarine was first carried out in France. Shortly before the
Franco-German war in 1870, M. Mege-Mouries, a French chemist,
was requested by the Emperor Napoleon III. to investigate the
question of obtaining a good cheap substitute for butter, for
the French Marines, and for the poorer inhabitants of Paris.
The animal fats of all domestic animals used for meat are not
suited for use for kitchen purposes, since for many purposes they
are partly too hard and friable, and partly too soft and greasy,
and since all of them possess a peculiar smell and flavour, pro-
bably caused by small quantities of volatile fatty acids. The
above-mentioned chemist quickly carried out his commission in
an excellent manner, and discovered by experiment a cheap butter
substitute possessing many excellent qualities, and capable of being
prepared in a simple manner from the best ox-tallow. According
to a regulation of the Paris Health Council of 12th April, 1872, the
public sale of the new fat, which was named margarine-mouries, was
sanctioned underHhe condition that it was not to be brought into
commerce under the name of butter. According to the process of
Mege-Mouries, a portion of stearin separated from the best kidney
fat is converted into a fat which possesses properties similar to
butter, and which has practically lost the peculiar flavour of raw
fat. This method thus renders the use of the fat of the animal

IIARGARINE. 317

body possible, and has given rise to a new fat, the so-called oleo-
margarine, which is capable of more extensive and varied uses than
the raw material from which it is derived. It is this idea which
gave rise to the preparation of margarine, a thoroughly wholesome
substance, against which nothing can be urged, and which indeed
should be welcomed, since it serves a most useful purpose.

The preparation of the new fat rapidly extended from France,
and became at first established in America, Germany, and Austria;
then in Russia and other countries. Up to the end of 1880 nearly
all the so-called artificial butter sold in Europe was prepared accord-
ing to the excellent process of Mege-Mouries. As the new fat was
in its original state truly an excellent cooking-fat, containing a
somewhat larger percentage of fat, and therefore more economical
than butter, and as it possessed better keeping qualities, and also
excelled, both in quality and appetizing flavour, the common peasants'
butter, which was placed on the markets in great quantities, its use
steadily increased. Frankly, what helped to rapidly extend the use
of the fat was the fact that the name butterine, which had been
given to it, was very commonly confused with butter, and it was
introduced into commerce in large quantities as butter.

The large extension of the manufacture of margarine had the
result that the raw material which at first was solely used in its
manufacture, namely, fresh ox tallow, was soon no longer procurable
in the necessary quantity. According to the experiments carried
out at the butter factory, opened in the year 1873, at Leising near
Vienna, 100 kilos, of raw tallow yielded on an average 22 kilos, of
butterine. At the central cattle slaughter-house at Berlin in 1885,
there were killed yearly an average of 150,000 head of cattle. If it
be assumed that 90 kilos, of raw tallow was obtained per head, taking
each animal at 600 kilos, of live weight, and that this yielded 20
kilos, of butterine, we find the result to be, that from the fat of
150,000 head of cattle 3,000,000 kilos, of butterine could be made;
or, broadly speaking, about as much as was turned out at that time
from any one of the larger factories in a year. The result was that
the Mege-Mouries process of butterine manufacture was abandoned.
In order to increase the yield of oleomargarine, obtained by first
melting the raw fat at a temperature of 45° C, a temperature of 60°
C. was applied, and in addition the stearin was subjected to greater
pressure than was formerly the case. The result was that 100 kilos,
of raw tallow yielded 60 to 62 kilos, of oleomargarine instead of

318 SCIENCE AND PRACTICE OF DAIRYING.

20 kilos., which was formerly obtained, but the product was of an
inferior quality. It was richer in stearin, and possessed a higher
melting point (40° to 434° C.) in the poorer sorts, but a firmer
consistence. The other difiiculties which were met with in the
more extended use of this product were sought to be overcome.
Thus, in order to lower its melting point and to improve its condition,
the cheaper kinds of plant oils were employed, such as earth-nut
oil, cotton-seed oil, walnut oil, rape oil, the poorer sorts of olive oil,
the oil of fenugreek, cocoa oil, cocoa-kernel oil, sesame oil, &c.
In short, as an increase in the production of oleomargarine from
ox tallow was no longer possible, manufacturers were forced to
utilize other kinds of fat in the manufacture of oleomargarine,
which offered little difficulty, since, by the simultaneous use of plant
oils, fats of firmer consistency could be used.

The nature of the different kinds of fat which were used, or sup-
posed to be used, can be seen from the patents taken out in connec-
tion with this article. In addition to ox tallow the following were
used : — Veal tallow, bacon fat, goose fat, slaughter-house fat, stearin,
fat from soap-boiling manufacturers, and fat from flaying-houses,
a bad discoloured fat possessing a disagreeable smell, and purified
by treatment with strong mineral acids. At present the larger part
of the raw material of oleomargarine which is treated by the mar-
garine factories is no longer obtained in Europe, but by import from
North America, and probably from Australia, that is, from sources
not under inspection. This is not unimportant. Through certain
infectious diseases the fatty material of sick animals may undergo
changes which render very dangerous to mankind the consumption
of the fat obtained from them. By the careless preparation of oleo-
margarine, there is a possibility that the spores of animal parasites,
and, where traces of the muscle substances are contained in the fat,
€ven trichinise, may be introduced into the margarine. This is
all the more important, since in the preparation of oleomargarine a
temperature of at most 65° C. is employed, a temperature which
cannot be regarded as invariably effecting the destruction of the
above-mentioned organisms. Although up to the present no case of
illness has been proved to be directly due to the partaking of mar-
garine, this does not guarantee that serious outbreaks of illness
might not suddenly arise, due to the use of bad margarine. The
use of plant fats in the preparation of margarine is also open to
objection. Plant fats consist of different mixtures of fats from that

MARGARINE. 319

of animals, and are, as common experience has shown, less easily
digested than the latter.

It goes without saying, that attempts have been made, in order
to promote its sale, to make margarine as attractive as possible.
There is no reason, however, on this account, for rendering the new
fat similar in external appearance to butter, or for bringing it on
the market in a similar form and packed in the same way as butter.
The great resemblance of the prepared animal fats to butter has
always this disadvantage, that it opens the way to fraudulent
practices, and has thus a tendency to destroy the honest character
of the sale. The possibility of fraud was formerly increased by the
universal practice of calling margarine by the name of butterine;
that is, by a title which was only justified by the appearance of the
margarine, but which was otherwise strained on account of the fact
that not only was the chemical behaviour of the margarine, but also
its mechanical texture and fundamental condition, different from
that of butter.

Of more importance still than the use of the word butterine,
was the manufacture of mixtures of margarine and butter, and the
manufacture of mixed butters, which were commonly used in the
years 1884 and 1885. These different titles indicated, clearly enough,
the fraudulent intention which underlay them. It is hardly neces-
sary to add that no improvement in the food is effected by the
mixing of margarine with good butter. The mixture of butter
with foreign fat is practised solely for the purpose of increasing
the value of the very cheapest fat by the addition of good butter, so
that it may take the place of butter to a large extent, and that at
a relatively higher price; or for the purjjose of passing it off in the
market as butter. For these reasons this practice must be regarded
as an attempt to create a new and lucrative industry, at the expense
of the dairy industry, and of the less wealthy portion of the public.

Thus, in the course of time, the manufacture of margarine has
departed more and more from the healthy basis on which it was
started in 1870, and has threatened to become, to a serious extent, a
parasitic industr^^ It has placed the manufacture of butter at a
disadvantage, given an impetus to the perpetration of fraud, and has
thrown on the market a large quantity of food, the origin of which
is a mystery, and which everyone has a right to regard with distrust.
About ten years ago measures were adopted in most countries where
dairying was in an advanced state, Holland excepted, to free the

320 SCIENCE AND PRACTICE OF DAIRYING.

new industry from its unhealthy accretions, and to place it in its
former position. German agricultural interests effected, not with-
out much trouble, the passing, on Jul}^ 12th, 1887, of a law dealing
with the sale of butter substitutes. This law came into force in
October, 1887. If it did not entirely meet all the necessities of the
case, it nevertheless furnished, when stringently and watchfully
carried out, and in combination with the law of 14th May, 1879,
dealing with the consumption of foods and condiments, and the
conditions of their use, an important protection to agriculture and
to the public.

With regard to the development of the margarine industry in
the United States of North America, little is known to the author
of a detailed and definite nature. It would seem that the manu-
facture of margarine, since its commencement, has been carried on
with less care than in Europe. In the latter case the manufacture
was carried on practically according to the process of Mege-Mouries,
and according to a process patented by Mr. Paraf on April 8th,
1873, after Hortiny's specifications. The new food was not called
margarine but butterine.

Soon after the discovery was made by Mege-Mouries, attempts
were made in various quarters, at first with little success, to intro-
duce the manufacture of margarine into Austria- Hungary. The first
attempt originated with an American, Benford, who came to Vienna
in 1871, and who there exhibited samples of margarine, which were
discovered to consist for the most part of butter. Subsequently a
Belgian, RonstorfF, general consul for the republic of Uruguay,
exhibited at the first dairying exhibition held at Vienna in 1872
on the 13th to I7th December, several samples of margarine which,
according to his representations, were prepared from ox fat and milk.
His attempts to start the manufacture of margarine on a commercial
scale also failed. The first to introduce the manufacture successfully
into Vienna was Mr. Sarg, the owner of the world-renowned soap
factory at Leising. He built in Leising in 1873, with the help of a
French engineer, a factory, which was opened in 1874, after the
municipal authorities of Vienna had granted permission to sell the
new fat under the name of 'pH'ina Wiener sparhutter. The factory
of Sarg was one of the first and best arranged of the large margarine
factories started in Europe outside of France. It supplied margarine
which had been prepared from fresh ox tallow, and which was
prepared in an appetizing form. Among the many forms of

MARGARINE. 321

margarine which the author has had an opportunity of examining
in the course of time, the prima Wiener sparhutter was the best.

In Holland, so far as the author is aware, no margarine is made,
or, at any rate, sold as such. In that country the preparation of
mixed butter, since the year 1870, has been developed to an extent
which is found nowhere else. As long as the Dutch butter market
is in existence, there will be no lack of dealers to mix the superior
and the inferior kinds of butter, and produce an average saleable
article, and thus make profit. Against the method of mixing, which
is still carried on elsewhere, it is impossible to do anything. Butter
has, however, been mixed with all sorts of fats, a condition of affairs
which formerly only very rarely occurred. At the time of the
Franco-German war, when the demand for butter became greater
and greater in Holland, inferior butter, Galician, Russian, and
Finnish butter, at first mixed with milk and starch solution, and
subsequently also with fats and oils of different kinds, were all
worked together by a butter-worker and sold as butter or mixed
butter. The discovery of Mege-Mouries, which was either not at all,
or only to a very slight extent, utilized in Holland, merely helped to
further develop the mixed butter industry, by furnishing it with
acceptable raw material. From the use of butter-workers the
business advanced to the manufacture on a factory scale, and fac-
tories were erected to mix butter with fats, oils, milks, and colouring
matter in large butter- vats, at temperatures at which the fats in use
melted. The proportions in which these raw materials were mixed
were as follows: — 15 to 35 of milk, 40 to 70 of margarine, 13 to 35
of oil, and from 0 to o of butter. The better sorts contained, indeed,
an addition of from 10 to 20 per cent of the best butter. The de-
sired oily condition was imparted to tlie product by the addition of
a considerable quantity of oil, according as it was desired to produce
an article possessing a dull opaque substance, more of the nature of
a salve, or a transparent wax-like material. This difference in the
preparation accounts for the fact that the Dutch so-called artificial
butter, which, both in a salted and unsalted condition, is placed on
the market like butter, possesses no uniform chemical composition.
From the above short description, it will be seen that the preparation
of good margarine from fresh animal fat, obtained from healthy
animals, and without the addition of milk, cream, or butter, is a
useful and beneficial discovery. It has had the effect of utilizing
animal fats, and of rendering them capable of manifold application,

( M 175 ) X

322 SCIENCE AND PRACTICE OF DAIRYING.

and has permitted of their being used for the middle and lower
classes as a cheap cooking fat, and a good substitute for butter.
Good margarine is quite capable of entering into successful compe-
tition with poor kinds of butter, but not with first-class butter,
so that there can be no talk of a serious blow being dealt to
the butter trade or to dairying through its use. Nothing can be
objected against the preparation of margarine, as long as it is manu-
factured in such a way that the product is of an appetizing nature,
and free from all unhealthy adulterants. Its manufacture is wholly
justifiable, and no sensible man will deny the economic importance it
possesses, in so far as it supj)lies a want, and furnishes a valuable
public food.

The following paragraph gives the chemical composition of margarine
and mixed butters of different sources : —

French American ,^^ima Hamburg Mixed Butter

Margarine. Butterine. sprrtutter. Quality. Quajfty. QuaUty.

Water, 12-56 11-25 10-69 10-25 9-61 8-08

Fat, 86-24 87-15 87-45 85-88 86-26 84-15

Other organic matter, ( -, .^^^ , ^^ (0-46 1-75 1*62 2-14

ash and salt, ...J ^_ ( 1-40 2-12 2-51 5-63

100-00 100-00 100-00 100-00 100-00 100-00

The percentage of insoluble fatty acids in the Wiener sparbutter, and in
the Hamburg mixed butter, amount respectively to 95-59, 92-47, 93-58,
and 93-96. In the investigation according to the Reichert method, the
quantity used for the three Hamburg mixed butters was respectively 5-3,
2-8, and -9 c.c. of the tenth normal alkali solution, and the specific
gravity of the pure fat of the three samples of Hamburg mixed butter at
100° C. was respectively -8618, -8605, -8601. The Wiener sparbutter was
analysed by the author in 1887, and the others in 1886.

148. Margarine Cheese. — Margarine cheese was formerly known
as melted cheese, oleomargarine cheese, and artificial cheese. It is
now known as the kind of cheese which it imitates. While it was
possible to say of the preparation of margarine that it originated in
a proper idea, as was pointed out previously, and that it might be
regarded as a beneficial discovery, so long as there existed a want
that it could supply, and that it thereby justified its existence, it
was difficult to say the same of the preparation of margarine cheese.
No one can deny that the demand for butter exceeds that for cheese,
and that it is a benefit for the poorer section of the people, who are

MARGARINE CHEESE. 323

not able to buy the higher-priced butters, to have at their disposal,
instead of bad butter, a good, healthy, and cheap substitute. But
the demand for cheeses is, on the whole, by no means very great, and
the already limited area for the manufacture of cheeses abundantly
suffices for it. The demand for the finer kinds of cheeses is still
comparatively brisk, but it is not so for cheeses of the medium and
poorer kinds, such as skim-milk cheeses. In connection with the
consumption of cheese, the taste of the individual is an important
factor, and in large districts of Germany cheese is no longer a
popular food. The reason of this is not due to the fact that there is
a lack of good skim-milk cheeses, and that good cheeses have not
been successfully prepared from milk which has been skimmed by
means of centrifugal force. Where skill is not awanting, it is
possible to make good skim-milk cheese possessing a piquant
flavour. That this art has not yet become widely known cannot
be doubted, especially in Middle and North Germany, but as the
demand increases it will certainly be rapidly developed. In dis-
tricts in which a taste for cheese is awanting, or where the people
have not become accustomed to eating cheese, no market would be
found for margarine cheese, even although — which is a doubtful
point — margarine cheese excelled milk cheese in flavour. Nor can
the small use of skim-milk cheeses be explained on the groimd that
they are too dear, since there have been times when the h kilo, of
skim-milk cheese of good quality was, owing to a scarcity of demand,
to be had for 15 to 20 pfennig, a price at which a similar weight
of appetizing margarine cheese could not be supplied. It cannot
therefore be asserted that the preparation of margarine cheese meets
a pressing demand for public food, and that it has proved a benefit
to the working classes.

It must be noted that cheese in which nitrogenous matter i?
present, along with a considerable amount of fat, is more easily
digested than a skim-milk cheese poor in fat. This is certainly
true, but it does not mean that margarine is required in order to
increase the digestibility of skim-milk cheese. Whoever desires to
render this cheese more digestible, through the addition of fat,
would be better to do so by adding to his piece of cheese a piece of
good bacon fat, and eating this along with it, than by buying it in
margarine of a dubious origin.

Therefore it is not to be understood, after all that has been
said, that the preparation of margarine cheese can be economically

324 SCIENCE AND PRACTICE OF DAIRYING.

justified. Still less justifiable is the opinion that this branch of
dairying can supply a want.

It has been further claimed that the utilization of skim-milk,
which is found in some places to be very difficult to effect, would be
greatly assisted by the manufacture of margarine cheese. If this be
of any benefit, it can only be so in the same way as brandy is given
to a person who has fainted, in order to bring him again to his
senses. Margarine cheese manufacture is far more dangerous to the
manufacture of cheese than the manufacture of margarine is to the
pi'oduction of butter, and there can be no greater example of short-
sightedness than to expect assistance to the dairy industry, in its
time of need, from the help of a manufacture which utterly destroys
the cheese industry, and thereby strikes a blow at the entire dairy
industry. On the side of the dairies which have already entered
into contracts, it is asserted that the maximum value on an average
is not reached, and that the margarine cheese industry threatens
many results which would be highly disastrous to them. The
disadvantages consist in that the whey assumes, in the course of a
few hours, a very disagreeable smell, which is disadvantageous to
butter, that on this account it loses much of its value as a food,
and that it is not available for margarine manufacturing purposes,
and that it is capable of inflicting a deleterious influence on the sale
of butter. If more attention were given to the preparation of skim-
milk cheeses, the value of skim-milk would be much more consider-
ably increased than by the manufacture of margarine cheese. 100
kilos, of skim-milk will yield 10 kilos. of fresh skim-milk brick-shaped
cheeses, and, at the same time, 87 kilos, of sweet whey, leaving a loss
from the total weight of 3 per cent. If the cheese lose before its
sale 25 per cent in weight, so that only 7o kilos, of cheese are sold,
and if the kilo, of ripe cheese only fetches 36 pfennig, there is
obtained from the cheese, 7*5 x "36 = 2*7 marks.

The manufacturers of margarine cheese, naturally enough, oppose
the attempt to apply to the article the title of oleomargarine, or fatted
cheese, nor are such titles convenient for the public. For this reason,
there has been nothing to prevent the artificial products in common
use from appearing under the names of the different kinds of cheeses
of which they are the imitation. The buyer is then no longer certain
of procuring what he desires to purchase. Fraud is easily perpe-
trated and the whole cheese industry decays. It is for these reasons,
without doubt, the case that this new department of dairying is of no

MARGARINE CHEESE. 325

use, but on the other hand is only likely to do harm, and to render
all attempts made to improve the skim-milk industry abortive.

It has been said, finally, that margarine cheese is neither intended
nor will enter into competition with ordinary cheese, but constitutes
a new food, and is perfectly independent of the dairy industry. The
conception, which supports the opinion that an industry which has
for its object the imitation of one of the chief products of dairying,
will in no way effect dairying, is so obviously absurd, that it needs
no further consideration.

The preparation of margarine cheese, or, as it was formerly
called, artificial cheese, was introduced from the United States of
North America. Artificial cheese was already made in that country
as far back as 1878, from skim-milk which, after melted margarine
or other fat had been incorporated with it by special apparatus, was
manufactured into cheese, special precautions being taken on account
of the unstable state of the emulsion. This artificial cheese was,
from the very first, a source of annoyance to the American farmer,
and met with very little support from the public. In the course of
time the attempt was made to develop the industry, and to introduce
it into Europe, where the manufacture was begun in many countries,
especially in Denmark. In Germany it was first undertaken by A.
M. Mohr, of Barnfeld in Ottensted in Holstein, who took the matter
up, and who has during recent years made great attempts to set the
margarine trade into active motion. As has already been pointed
out, A. M. Mohr did not buy skim-milk cheese, but had the product
manufactured in dairies in which were the necessary utensils. The
apparatus for the incorporation of fat into the skim-milk were the
emulsion machines, which have been very much improved in the last
few years, so that it is possible to obtain a fineness of the fat
division not even exceeded by that of the butter-fat in milk itself.
The most extensively used of these machines are the Danish, and
those of Dr. De Laval. Both machines are centrifugal machines,
and respectively make 4500 and 7000 revolutions per minute. By
means of these machines, there is made in the manufacture of
margarine cheese, from a definite proportion of skim-milk and mar-
garine, an emulsion which is known to the manufacturer by the
name of artificial cream, and which is added to the skim-milk which
it is desired to manufacture into cheese, in such a proportion, that
for every 100 kilos, of skim-milk there are about 3 kilos, of mar-
garine. Despite the extraordinary fineness of the division of the fat,

326 SCIENCE AND PRACTICE OF DAIRYING,

SO long as it is melted, it rises very quickly to the surface of the
cheese-vat, so that even when the coagulation-time is of the shortest
possible duration, there is always a small portion of the melted fat
lost to the margarine cheese. It is, of course, obvious that the best
kind of fat, such as is employed in the preparation of butter substi-
tutes, is not used, but inferior fat and refuse from the margarine
factories. This fact is admitted by the manufacturer. In conse-
quence of the fact that the fat, during the process of emulsification,
is submitted to the high temperature of 60° C, and that it offers an
enormously large surface to the action of the oxygen of the air, it is
further deteriorated. The result is, as is often noticed in the manu-
facture of cheese in this way, that the whey remaining behind often
after a few hours gives off" a highly disagreeable smell. The
manufacture of margarine cheese is far more troublesome than the
manufacture of genuine cheese, and its value depends to a large
extent on the quantity and condition of the fat added to the skim-
milk. The author has formerly had many opportunities of testing
and examining American cheeses, although he has never seen the
Mohr products. According to reports in the dairy newspapers, they
do not possess good keeping properties, and are very liable to mould.
They are prepared usually according to the Cheddar method, but
also according to the method employed in the making of Limburg,
Gouda, and Edam cheeses, and even after the method of the
Stilton. With regard to their flavour nothing can be said. In
margarine bad fat can be very easily detected. In ripe margarine
cheeses it is less easily detected. Anyone with a good appetite may
enjoy this kind of cheese, but it is not a common taste. It is not
suited for the tables of the rich. The manufacturers of margarine
cheese must therefore find an outlet for their cheese chiefly among
the poorer classes, and it is this portion of the public who must pay
for the whole industry, without obtaining any advantage. Neither
in Germany nor elsewhere is margarine cheese popular. Whether
this is due to its quality, or to a healthy instinctive feeling on the
part of the public, is doubtful.

A careful consideration of all the conditions of the trade proves
the margarine cheese industry to be of a purely parasitic character.
It benefits no one except itself, and grows rich at the expense of the
poorer classes and the dairy industry. That there should be dairies
which do not scruple to work in the interests of this industry, is as
difficult to understand as it is lamentable.

CHAPTER IX.

EXPLANATIOX OF THE APPENDED TABLES.

149. In the preceding paragraphs different works and calcula-
tions have been referred to in the sections describing dairying, to
illustrate which, calculation tables are either necessary or extremely
desirable in the interests of economy of time. The number of tables
which have been devised in the interests of dairying have in the
course of time become so greatly increased, that it is impossible to
publish all of them in a text-book. The author will consequently
only give a few which are most frequently required for use.

Those given here are as follows: —

Table I. Comparison of Fahrenheit, Centigrade, and Beaumiir
Thermonietric Scales. — The temperature can be converted from one
scale into the other by the following formulae: —

n° F.=f (n-32)° G.-^ (71-32)° R.

= •555 (n-32)°C.=:-444 (7i-32)= R.
n° C. = * 71° R. = (| « + 32)° F.

= .8 7i°R.rr:(1.8n + 32)°F.
n° R. = (I n + 32)° Y.-^n C.

= (2-25 w + 32)°F. = 1.25 n° C.

To convert a given temperature on the Fahrenheit scale to
degrees Centigrade, subtract 32 and multiply by |, when the answer
will be the required temperature on the Centigrade scale. The
following is an example: —

173' Fahr. = 173 - 32 X 1 = 78-33° C.

To convert a given temperature on the Centigrade scale to the
Fahrenheit, multiply by f and add 82. The following is an

example : —

60° C. =: 60 X f + 32 = 140° Fahr.

The space between boiling point and freezing in Reaumur is
divided into 80, in the Centigrade or Celsius into 100, and in the
Fahrenheit into 180 equal divisions. The boiling point is respec-
tively indicated by 80^, 100°, and 212°, and the freezing point by
0°, 0^ and 32''. On the Fahrenheit scale under the freezing point
there are 32 degrees.

Tables II. and III. are arranged for the correction of the specific

328 SCIENCE AND PRACTICE OF DAIRYING.

gravity of milk and skim-milk (observed at temperatures from 0°
and 30° C), to 15° C. All comparisons are made at that tempera-
ture, for the sake of simplicity in practice. When the specific gravity
of milk is stated, the first two figures, along with the point, are
removed. Thus, for example, a sample of milk having a specific
gravity of 1'03175 at 15° C, is spoken of as having a specific gravity
of 31-75.

For example, if the specific gravity of milk at 24° C. has been
found to be 2970; at 15° C, therefore, it will be 31-2 + '1 X "7, equal
to 31-9. There is found on Table II. the numbers 31*2 and 32-2
for 29 and 30 respectively, at 24° C. The difiierence for one degree
amounts to 1, for a tenth of a degree '1, and for seven-tenths '7.

The specific gravity of milk may be stated in difiierent ways.
It may be stated in comparison to distilled water at 15° C, and
weighed in air, or it may be stated in comparison with water at 4°
C, and weighed in air or water at 4° C, and calculated in vacuum.
According to the method of comparison, the numbers will naturally
differ. If, for example, the specific gravity of a sample of milk
has been determined by the pyknometer at 15° C. and compared
with distilled water at the same temperature, and weighed in air,
and found to be 1"0315, and if it be desired to convert this number
into comparison with water at 4° C, taking the density of water at
15° C. at "99916, then the figure will be found by multiplying
1-0315 by -99916, that is, 1-03063. The difference amounts to
1-0315 -1-03063 = -00087. If it be desired to calculate this in
vacuum, it will be found by multiplying 1-0315 into (-99916 —
00119) -f- -00119, that is, 1-03060. The figures, then, for specific
gravities are as follows: —

Weighed in air and compared with water at 15° C, equal to 1-03150.

4°C., „ 1-03063.
„ in vacuum ,, 4° C, „ 1-03060.

As it is sufficient for practical and scientific purposes to know
the specific gravity to four places of decimals, it will make little
difference whether it is calculated to water at 4° C, or whether it is
weighed in vacuum or not. On the other hand, it is not the same
whether the specific gravity be taken with reference to water at
15° C. or at 4° C. As a rule, the specific gravity of milk is calcu-
lated at 15° C, and compared with distilled water at the same
temperature.

AN EXPLANATION OF THE APPENDED TABLES. 329

Table IV A. and IV b. serve for the calculation of total solids (t)
when the specific gravity (s) at 15° C. and the percentage of fat (/)
are known. Both tables are based on the following formula: —

nxl.07527-1 . n lOOxs-100

(1) t = :j x/+ -. X .

n-1 J^-l s

In the above formula (n) equals the specific gravity of the solids
not fat at 15° C. This amount, as has already been pointed out,
is very nearly constant. It may be worth while to calculate its
value in those districts in which the above formula will be used.
This can be done by the following formula: —

,0^ - sxsHt-f)

^-'' " " 100 X si - s X si {100 -t)-sxf

in which (s^) is the specific gravity of the butter -fat at 15° C.
compared with water at a similar temperature.

If 1 '600734 be taken for the value of (n), as stated in formula
(1), the following will be the result. Substituting for the figures
100xs-100 = c?:—

(3) < = l-2x/+2.665x— ^,

and from this we obtain the following: —

^=. 833 x<- 2-22 x^,
s'

and

lOOG

1000-3-75 (t-l-2xf)

If, for example, it had been calculated that (s) = l"0321 and
(/) = 3-456 per cent, from Table IV a. for 1-2 x/=4-147 per cent, and

from Table IV B. 2-665 x ^^ = 8288 per cent; therefore (0 = 12-435
pel- cent.

Both tables can be used for the calculation of (/), if (s) and (t)
are given, for from equation (3) it follows that

«-2-665x-
•' 1-2

If, therefore, (t) equals 12-435 and (s) 1-0321 from Table IVb., its
value would be 2-665 x - =8-288. If we take this number from

12*435, the figure 4-147 is found, a number which, by division with
1'2, gives the percentage of fat at 3-456 per cent.

330 SCIENCE AND PRACTICE OF DAIRYING.

Table V. serves for calculating the specific gravity (m) of the total
solids of milk at 15° C, compared with water at like temperature.

In many cases where the question arises as to whether milk has
been adulterated or not, as has already been pointed out in § 31,
page 69, the value of m can be obtained from the formula,

m= J .

in which (t) equals 12*435 per cent, and (.s) equals 1*032]. From
Table V. we obtain for - =3110. If one subtracts this number

and divides 12-435 by the remainder, 9'325, we obtain (in) equal
to 1-333.

Table VI., calculated by J. Nisius, gives the relation of the
percentage of fat (p) and specific gravity of the total solids (vx)
of milk. In order to distinguish among several samples of milk
the compositions of those which are known to be comparatively
rich in fat, that is, in comparison with the non-fatty solids, the
composition of all the samples must be calculated to a similar
percentage of total solids. Formerly, in such a comparison, the
percentage 12 or 12*5 was generally chosen. It appeared to the
author to be more suitable to calculate the percentage of the amount
of fat in the dry substance.

(m) can easily be calculated if (p) is given, or (p) if (m) is
given.

By the formula

_ 2665
'^"1665 + 12x23

the followino; is obtained:

(1) m^^„ ,J^^,. ' and (2) y=-, .^^ -138-90.

For (p) 27-792 per cent, for example, (m) equals If^- equals
1-334, and where (m) equals 1-334 (p) will be 27-80 per cent.

TABLE I.

331

TABLE I.

Coinpariso7i of Fahrenheit and Centigrade Thermometric Scales.

0-00

20-56

106

41-11

143

61-67

180

82-22

0-56

21-11

107

41-67

144

62-22

181

82-78

1-11

21-67

108

42-22

145

62-78

182

83-33

1-67

22-22

109

42-78

146

63-33

183

83-89

2-22

22-78

110

43-33

147

63-89

184

84-44

2-78

23-33

111

43-89

148

64-44

185

85-00

333

23-89

112

44-44

149

65 00

186

85-56

3-89

24-44

113

45-00

150

65-56

187

86-11

4-44

25-00

114

45-56

151

66-11

188

86-67

5-00

25-56

115

46-11

152

66-67

189

87-22

5-56

26-11

116

46-67

153

67-22

190

87-78

6-11

26-67

117

47-22

154

67-78

191

88-33

6-67

27-22

118

47-78

155

68-33

192

88-89

7-22

27-78

119

48-33

156

68-89

193

89-44

7-78

28-33

120

48-89

157

69-44

194

90-00

8-33

28-89

121

49-44

158

70-00

195

90-56

8-89

29-44

122

50-00

159

70-56

196

91-11

9-44

30-00

123

50-56

160

71-11

197

91-67

10-00

30-56

124

51-11

161

71-67

198

92-22

10-56

31-11

125

51-67

162

72-22

199

92-78

11-11

31-67

126

52-22

163

72-78

200

93-33

11-67

32-22

127

52-78

164

73-33

201

93-89

12-22

32-78

128

53-33

165

73-89

202

94-44

12-78

33-33

129

53-89

166

74-44

203

95-00

13-33

33-89

130

54-44

167

75-00

204

95-56

13-89

34-44

131

55-00

168

75-56

205

96-11

14-44

35-00

132

55-56

.169

76-11

206

96-67

15-00

35-56

133

56-11

170

76-67

207

97-22

15-56

36-11

134

56-67

171

77-22

208

97-78

16-11

36-67

135

57-22

172

77-78

209

98-33

16-67

37-22

136

57-78

173

78-33

210

98-89

17-22

100

37-78

137

58-33

174

78-89

211

99-44

17-78

101

38-33

138

58-89

175

79-44

212

10000

18-33

102

38-89

139

59-44

176

80-00

18-89

103

39-44

140

60-00

177

80-56

19-44

104

40-00

141

60-56

178

81-11

20-00

105

40-56

142

61-11

179

81-67

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Directions for Use. — Suppose the specific gravity found at 18° C, to be I'OSO, this
is represented in the Table, on the horizontal line at the top, by the last two figures, viz.
30. Under the figure 30, the number corresponding to the temperature 18° C (in the
vertical column at the sides of the table) is found, which in this case is 30"6, and repre.sent3
the sfiecific gravity at 15° C.

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For explanation of the use of this Table see Table II.
333

TABLE IVa.

For Calculating the Total Solids t, from the Specific Gravity s, a7id the
percentage of Fat f.

For the calculation of t. To be used in conjunction with Table IVb.

1-2 x/

100

1-2(H)

1-50

1-800

200

2-400

2-50

3-000

3-00

3-600

1-212

1-812

2-412

3-012

3-612

1-224

1-824

2-424

3-024

3-624

05 O

1-236

1-836

2-436

3-036

3-636

1-248

1-848

2-448

3-048

3-648

1-260

1-860

2-460

3-060

3-660

1-272

1-872

2-472

3-072

3-672

1-284

1-884

3-484

3-084

3-684

X O

1-296

1-896

2-496

3-096

3-696

1-308

1-908

2-508

3-108

3-708

liO

1-320

1-60

1-920

2-10

2-520

260

3-120

310

3-720

o
t» o

1-332

1-932

1 2-532

3132

3-732

1-344

1-944

2-544

3-144

3-744

1-356
1-368

1-956
1-968

13
14

2-556
2-568

63
64

3-156
3-168

13
14

3-756
3-768

1-380

1-980

2-580

3-180

3-780

1-392

1-992

2-592

3-192

2-792

CD O

1-404

2-004

2-604

3-204

3-804

1-416

1-428

68
69

2-016

2-028

18
19

2-616
2-628

68
69

3-216

3-228

18
19

3-816

3-828

iC o

1-20

1-440

1-70

2-040

2-20

2-640

2-70

3-240

3 20

3-840

1-452

2-052

2-652

3-252

3-852

1-464
1-476

72
73

2-064
2-076

22
23

2-664
2-676

72
73

3-264
3-276

22
23

3-864
3-876

1-488

2-088

2-688

3-288

3-888

1-500

2-100

2-700

3-300

3-900

o
•* o

1-512

2-112

2-712

3-312

3-912

1-524
1-536

77
78

2-124
2-136

27
28

2-724
2-736

77
78

3-324
3-336

27
28

3-924
3-936

1-548

2-148

2-748

3-348

3-948

CO C

130

1-560

180

2-160

2-30

2-760

280

3-360

330

3-960

1-572

2-172

2-772

3-372

3-972

1-584

2-184

2-784

3-384

3-984

1-596

2-196

2-796

3-396

3-996

1-608

2-208

2-808

3-408

4-008

CN O

1-620

2-220

2-820

3-420

4-020

1-632

1-644

2-232

2-244

36
37

2-832
2-844

3-432

3-444

36
37

4-032
4-044

1-656

2-256

2-856

3-456

4-056

1-668

2-268

2-868

3-468

4-068

1-40

1-680

1-90

2-2S0

2-40

2-880

290

3-480

340

4-080

1-692

2-29:i

2-892

3-492

4-092

s^_ •

1-704

2-304

2-904

3-504

4-104

tl-H

1-716

2-316

2-916

3-516

4-116

1-728

2-328

2-928

3-528

4-128

1-740

2-340

2-940

3-540

4-140

1-752

2-352

2-952

3-552

4-152

1-764

2-364

2-964

3-564

4-164

1-776

2-376

2-976

3-576

4-176

^:§

1-788

2-388

2-988

3-588

4-188

g-i

150

1 -800

200

2-400

250

3-000 1

300

3-600

3-50

4-200

TABLE

IVa.-

-{Continued).

1-2 x/

1-2 x/"

1-2 x/

3-50

4-200

4-00

4-800

4-50

5-400

500

6-000

5-50

6-600

4-212

4-812

5-412

6-012

6-612

4-224

4-824

5-424

6-024

6-624

C5 O

4-236

4-836

5-436

6-036

6-636

4-248
4-260

04
05

4-848
4-860

54
55

5-448
5-460

04
05

6-048
6-060

54
55

6-648
6-660

4-272

4-872

5-472

6-072

6-672

4-284

4-884

5-484

6-084

6-684

X p

4-296

4-896

5-496

6-096

6-696

4-308

4-908

5-508

6-108

6-708

360

4-320

4-10

4-920

4-60

5-520

5-10

6-120

5-60

6-720

4-332

4-932

5-532

6-132

6-732

4-344

4-944

5-544

6-144

6-744

4-356
4-368

13
14

4-956
4-968

63
64

5-556
5-568

6-156
6-168

6-756
6-768

4-380

4-980

5-580

6-180

6-780

4-392

4-992

5-592

6-192

6-792

CO o

4-404

5-004

5-604

6-204

6-804

4-416

4-428

18
19

5-016
5-028

68
69

5-616

5-628

18
19

6-216

6-228

68
69

6-816
6-828

CD
O

3-70

4-440

4-20

5-040

4-70

5-640

5-20

6-240

5-70

6-840

4-452

5-052

5-652

6-252

6-852

4-464
4-476

22
23

5-064
5-076

72
73

5-664
5-676

22
23

6-264
6-276

72
73

6-864
6-876

4-488

5-088

5-688

6-288

6-888

«c

4-500

5-100

5-700

6-300

6-900

Tt< O

4-512

5-112

5-712

6-312

6-912

4-524

5-124

5-724

6324

6924

4-536

5-136

5-736

6-336

6-936

4-548

5-148

5-748

6-348

6-948

CO 5
6

380

4-560

4-30

5-160

4-80

5-760

5-30

6-360

5-80

6-960

4-572
4-584

31
32

5-172
5-184

5-772

5-784

31
32

6-372

6-384

6-972
6-984

4-596

5-196

5-796

6 396

6-996

(71

4-608

5-208

5-808

6-408

7-008

(N O

4-620

5-220

5-820

6-420

7-020

4-632

5-232

5-832

6-432

7032

4-644

5-244

5-844

6-444

7-044

4-656

5-256

5-856

6-456

7-056

4-668

5-268

5-868

■6-468

5-90

7-068

390

4-680

4-40

5-280

490

5-880

5-40

6-480

7-080

4-692

5-292

5-892

6-492

7-092

s^ -

4-704

5-304

5-904

6-504

7104

o :

4-716

5-316

5-916

6-516

7-116

CO :

4-728

5-328

5-928

6-528

7-128

4-740

5-340

5-940

6-540

7-140

c ;

4-752

5-352

5-952

6-552

7-152

1 :

4-764

5-364

5-964

6-564

7-164

c •

4-776

5-376

5-976

6-576

7-176

'-U ^'

4-788

5-388

5-988

6-588

7-188

400

4-800

4-50

5-400

500

6-000

550

6-600

1600

7-200

Directions fob Use. — If the fat (/) is found on analysis to be 3-45 per cent, then
the column under /is examined till the number 3-45 is found, and its equivalent in the
column headed 1-2 x/ is noted. This is found in this case to be 4-14. This amount,
added to the result found from Table IV b. (for the use of which see the accompanying
directions), gives the percentage of total solids.

33j

TABLE IVb.

For Calculating the Total Solids t, from the Specific Gravity s, and

the percentage of Fat f.

For the calculation of t. To be used in conjunction with Table IVa.

Thou-

2-665 X fl

Thou-

2-665 x^?

Thou-

2-665 X ^^

Thou-

2-665 x^

Thou-

2-665 x'i

sandths

190

4-967

240

6-246

29-0

7-511

340

S-763

39^

10-003

4-994

6-271

7-536

8-788

10-028

5-021

6-297

7-561

8-813

10-053

5-047

6-322

7-586

8-838

10-077

5-072

6-348

7-611

8-863

10-102

5-098

6-373

7-636

8-888

10-127

5-122

6-398

7-662

8-912

10-151

5-149

6-424

7-687

8-937

10-176

5-173

6-449

7-712

8-962

10-201

5-199

6-475

7-737

8-987

10-225

200

5-225

25-0

6-500

30-0

7-762

350

9-012

40-0

10-250

5-251

6-525

7-787

9-037

5-277

6-551

7-812

9-062

5-302

6-576

7-837

9-087

TS -« 1 » m

5-328

6-601

7-863

9-111

X j3

5-353

6-627

7-888

9-136

5-379

6-652

7-913

9-161

<N -*■

5-405

6-677

7-938

9-186

-S ^

5-430

•8

6-703

7-963

9-211

■cS

5-456

6-728

7-988

9-236

CO
o

210

5-481

260

6-753

31-0

8-013

360

9-261

G TO CO

5-507

6-779

8-038

9-285

"o IS "o

5-532

6-804

8-063

9-310

5-558

6-829

8-088

9-335

5-584

6-855

8-113

9-360

T -gfo

5-609

6-880

8-138

9-385

-£«

CO ^ -g

5-635

6-905

8-163

9-409

5-660

6-930

8-188

9-434

> 'wo;

5-686

6-956

8-213

9-459

1 o S

5-711

6-981

8-239

9-484

220

5-737

27-0

7-006

32-0

8-264

370

9-509

o o>

5-762

7 032

]

8-289

9-533

^ •'^ be

-*-3 &JD «

5-788

7-057

8-314

9-558

■^ .S w

5-813

7-082

8-339

9-583

5-839

7-107

8-364

9-608

-Q

2 a^

5-864

7133

8-389

9-632

tlj M CD

5-890

7-158

8-414

9-657

-^ 8^

5-915

7-183

8-439

9-682

3 s- c

5-941

7-208

8-464

9-707

M
1

5-966

7-234

8-489

9-732

S s

0) 3 3

230

5-992

28-0

7-259

330

8-514

38 0

9-756

r-< a> h

6017

7-284

8-539

9-781

.5 ^ (U

6-042

7-309

8-563

9-806

6-068

7-334

8-588

9-830

girt

6-093

7-360

8-613

9-855

03 -^ 03

2 '^ -S

6-119

7-385

8-638

9-880

01 .S c

6-144

7-410

8-663

9-904

6-170

7-435

8-688

9-929

to <p x)

6-195

7-460

8-713

9-954

5 .2'i

6-221

7-485

8-738

9-979

240

1 6-246

290

1 7-511

34-0

8-763

39-0

l()-()03

TABLE V.

For calculating Specific Gravity of the Total Solids of Milk m, from the Specific
Gravity s, and the percentage of Total Solids t.

Thou-
sandths

190

1-864

24-0

2-344

290

2-818

340

3-288

390

3-754

1-874

2-353

2-828

3-298

3-763

1-884

2-363

2-837

3-307

3-772

1-894

2-372

2-847

3-316

3-781

1-903

2-382

2-856

3-326

3-791

1-913

2-391

2-865

3-335

3-800

1-922

2-401

2-875

3-344

3-809

1-932

2-410

2-884

3-354

3-818

1-941

2-420

2-894

3-363

3-828

1-951

2-429

2-903

3-372

3-837

200

1-961

25-0

2-439

300

2-913

350

3-382

400

3-846

1-970

2-44y

2-922

3-391

1-980

2-458

2-931

3-400

1-990

2-468

2-941

3-410

1-999

2-477

2-950

3-419

> "x.

2-009

2-487

2-960

3-428

Id-^

■rf

2-018

2-496

2-969

3-438

u "

2-028

2-506

2-979

3-447

C£3 C
'o „

2-038

2-515

2-988

3-456

2-047

2-525

2-997

3-466

c3 ^~

210

2-057

260

2-534

31-0

3-007

36-0

3-475

(P CO

2-066

2-544

3016

3-484

'T3 CO
• - CO

2-076

2-553

3-026

3-494

^ <D

2-086

2-563

3035

3-503

^ -^

2-095

2-572

3-044

3-512

1 -

2-105

2-582

3 054

3-521

CO ^a

2-114

2-591

3-063

3-531

CO '^

2-124

2-601

3-073

3-540

■?* T-H

(u .2

2-133

2-610

3-082

3-549

£3 (N

'~' CO

-fi ,-,

2-143

2-620

3091

3-559

2 3

-o -S-

220

2-153

27-0

2-629

320

3-101

37-0

3-568

2-162

2-638

3-110

3-577

s §

2-172

2-648

3-120

3-587

""o "^

o _

to (4

2-181

2-657

3-129

3-596

" >. 3 -2

2-191

2-667

3-138

3-605

5 !>

2-200

2-676

3-148

3-614

o J

a) ■g

2-210

2-686

3-157

3-624

■" o

2-220

2-695

3-166

3-633

1 .^

2-229

2-705

3176

3-642

M O. tS >
Is— ?*

2-239

2-714

3-185

3-652

1 S-i

\-> CO

§2

230

2-248

28-0

2-724

330

3-195

380

3-661

2-258

2-733

3-204

3-670

2-267

2-743

3-213

3-679

^ a

g M

2-277

2-752

3-223

3689

00 ^

•2 ^

2-286

2-762

3-232

3-698

o ^

' =^ *!,

2-296

2-771

3-241

3-707

o c^

2-306

2-780

3-251

3-717

F-H CO

T" OS

2-315

2-790

3-260

3-726

II .2

2-325

2-799

3-269

3-735

2-334

2-809

3-279

3-744

240

2-344

290

2-818

340

3-288

390

3-754

(M175)

TABLE VI.

Showing the relation bet mm the percentage of Fat p, and the Specific Gravity
of the Total Solids m of Milk. Directions for use, see p. 30.

1-601

1-493

1-399

1-316

1-242

1-589

1-483

1-390

1-308

1-236

1-578

1-473

1-382

1-301

1-229

1-567

1-463

1-373

1-293

1-222

1-556

1-454

1-365

1-286

1-215

1-545

1-444

1-356

1-278

1-209

1-534

1-435

1-348

1-271

1-202

1-524

1-426

1-340

1-264

1-196

1-513

1-417

1-332

1-256

1-189

1-503

1-408

1-324

1-249

1-183

1-493

1-399

1-316

1-242

1-177

COMPARISON OF THE METRICAL WITH THE
COMMON MEASURES.

MEASURES OF LENGTH.

In English
Indies.

Millimeter, ,
Centimeter,
Decimeter, ,
Meter,

0-03937

0-39371

3-93708

39-37079

In English In English

Feet Yards

= 12 Inches. =3 Feet.

0-0032809 0-0010936

0-0328090 0-0109363

0-3280899 0-1093633

3-2808992 1-0936331

In English
Fathoms
= 6 Feet.

0-0005468
0-0054682
0-0546816
0-5468165

In English

Miles

= 1760 Yards.

0-0000006
0-0000062
0-0000621
0-0006214

1 Inch =2-539944 Centimeters.
1 Foot =3-0479449 Decimeters.
1 Yard=0-914.3S348 Meter.
1 Mile =1-6093140 Kilometers.

1 Square Inch =6-4515669 Square Centimeters.

1 Square Foot =9 2899683 Square Centimeters.

1 Square Yard = 0-83609715 Square Meter or Centiare.

1 Acre =0-404671021 Hectare.

MEASURES OF CAPACITY.

Milliliter or cub. centimeter,
Centiliter or 10 cu. centim.,
Deciliter or 100 cu. centim.,
Liter or cubic decimeter, . . ,

In Cubic
Inches.

0-061027

0-610271

6 102705

61-027052

In Cubic

Feet

= 1728 Cub.

Inches.

In Pints

= 34 65923

Cub. Inches.

0-0000353
0-0003532
0-0035317
0 0353166

0-001761
0-017608
0-176077
1-760773

In Gallons In Bushels

= 8 Pints =8 Gallons

= 277-27384 I =2218 19075

Cubic Inches.! Cubic Inches.

0-00022010
0-00220097
0-02-200967
0-22009668

0-000027512
0-000275121
0-002751208
0-027512085

1 Cubic Inch = 16-3861759 Cubic Centimeters. 1 Cubic Foot = 28-3153119 Cubic Decimeters.

1 Gallon = 4 -543457969 Liters.

MEASURES OF WEIGHT.

Milligram, . .
Centigram, .
Decigram,...

Gram,

Decagram,..
Hectogram,
Kilogram,...

In English
Grains.

0-015432

0-154323

1-543235

15-4.32349

154-3-23488

1543-234880

15432-348800

In Troy
Ounces

= 480
Grains.

0-000032
0-000322
0-003215
0-032151
0-321507
3-215073
32-150727

In Avoir-
dupois Lbs.
= 7000
Grains.

0-0000022
0-0000220
0-0002205
0-0022046
0-02-20462
0-2204621
2-2046213

In Cwts.

=112 Lbs.

= 734,000

Grains.

0-00000002
0-00000020
0-00000197
0 00001968
0 00019684
0-00196841
0-01968412

In Tons
= 20 Cwts.
= 15,6-20,000

Grains.

0-000000001
0-000000010
0-000000098
0-000000984
0-000009842
0-000098421
0-000984206

1 Grain
1 Troy oz.

= 0-06479895 Gram.
= 31-103496 Grams.

1 Lb. Avd. = 0-45359265 Kilogr.
1 Cwt. =50-80237689 Kilogr.

338

INDEX.

Acarus siro, 232.

Acid generator, preparation of, 99.

Acidity of milk, determination of, 204.

Acids, coagulation of milk by, 201.

Adams' fat estimation method, S3-S4.

Adulteration of, butter, 195; milk, t)5-74.

Aerobic bacteria, 95.

Aerometric estimation of milk-fat, 70.

Age of cows, value of knowledge of, 40.

Albuminoids of milk, 15-19.

Albuminose, 16.

Alcohol, preparation of, from whey, 270.

Alexandria cream-separator, 121.

Alpha separators, 129, 131-132, 133, 134.

Alveoli, 2.

American butterine, composition of, .322.

American Cheddar cheese, 249.

Ammonia in milk, 30.

Amphoteric reaction of milk, 11-12.

Anaerobic bacteria, 95.

Analysis of, butter, 195-199; cheese, 272-275:

milk, 80-88.
Annatto colouring matter, 177.
Antiquity of cheese-making, 243.
Arnoldt's hand separator, 128.
Aroma of milk, 190.
Ash of, butter, composition of, 195 ; cheese,

274; milk, determination of, 86; whey,

composition of, 270.

Baby separators, 132, 133, 134.

Bacillus, cyanogenus, 101 ; diatrypeticus

casei, 260; synsanthus, 101.
Backstein cheese, 274.
Bactei-ia of milk, 89-105 ; development of,

93; different forms of, 91, 93; forms and

life conditions of, 93; injurious action of,

in milk, 89.
Bacteriology and dairying, 89-105; practical

application of, 105.
Balance separator, 140.
Bavarian Algau, 258.
Beastings, 35.
Beating churns, 161, 162.
Benzoic acid in milk, detection of, 88.
Bergedoff's Iron Co.'s separatoi-s, 129, 133.
Bicarbonate of soda in milk, detection of, 87.
Bitter butter, 192.
Boiled milk, detection of, 88.
Books for dairy, keeping of, 305-310.

Boracic acid ; in milk, detection of, 87; in
rennet, 208.

Box churns, 162.

Budding fungi, 91.

Buffalo milk, 57; cheese from, 265; composi-
tion of, 57; properties of, 57; .specific
gravity of, 57; yield of, 57.

Bulling, effect of, on milk, 40.

Butter, 106, 169-199; analysis of, 195-199;
appearance of, faults in, 192; chemical
composition of, 193-195; colouring of, 177;
defects in, 192; different kinds of, 185;
faults of, 191-193; flavour and smell of,
defects in, 192; fresh, 185; good, properties
of, 191; influence of feeding on properties
of, 191; investigation and testing of, 195-
199; methods in which made, 106; nature
of, 159; Petersburg, 185; physical charac-
teristics of, 191; preserved, 186; properties
of, 169; salting of, 178; separation of, in
churning, 160; sjjecific gravity of, 194;
water in, 169, ISO, 193; working and knead-
ing of, 179; yield of, 184.

Butter-churns, 160-166.

Butter colours, 177.

Butter-extractors, 175-177.

Butter-fat, properties of, 196.

Butterine, 316-322.

Butter-knife, ISO.

Butter-making, general remarks on, 159-161.

Butter-milk, 160, 188-189; ash of, 189; com-
position of, 189; uses of, 189.

Butter-separator, 175-177.

Butter-sj'ringe, 180.

Butter-trough, 182.

Butter workers, ISO-lSl.

Butyric acid, 103.

Bye-products of milk, 294.

Byre, treatment of milk in, 60-61.

Byre-butter, 186.

Byre-test for milk, 72.

Calculations for methods of milk utilization,

302-306.
Calves, feeding of, with skim-milk, 157.
Calves' stomachs, preparation of rennet from,

208.
Calving time of cows, regulation of, 80.
Capillary blood-vessels, 3.
Carbonates in milk, detection of, 87.

339

340

SCIENCE AND PRACTICE OF DAIRYING.

Carbonic acid in milk, 27, 30.

Casein, composition of, 17, 202; heat equiva-
lent of, 18; in milk, 15, 18; precipitation
of, 18.

Casein-gum, 295.

Centrifugal acceleration, 125.

Centrifugal force, 119, 125; value of, for
creaming milk, 120.

Centrifugal machines, proper working of , 149.

Centrifugal separators, 120-153.

Cheddar cheese, 2i9.

Cheese, 200-275; analysis of, 272-275; art of
making, 234-235; Cheddar, 249; buffalo-
milk, 265; chemical composition of, 272;
classification of, 243-246; colouring of,
213; defects of, 241; different kinds of,
243-246; Edam, 253; Emmenthaler, 256-
261; goat-milk, 265; hard, 248; hot-iron
test of, 220; liquid residue of, 269; micro-
organisms in, 102, 239-241; Neufchatel,
247; potato, 267; preparation of, for mar-
ket, 242; pressing of, 223-227; reindeer-
milk, 265; ripening of, 102-103, 231-233,
236-243; salting of, 227-231; shaping of,
221-223; sheep-milk, 261; soft, 246-247;
sour-milk, 266-268; utensils for preparation
of, 214; utilization of milk in manufacture
of, 298, yield of, 270.

Cheese-kettles, 215-218, 220.

Cheese-knives, 218, 219.

Cheese-ladles, 219.

Cheese-milk, 269.

Cheese refuse, products from, 268.

Cheese-tubs, 214.

Cheese-vats, 214-218, 224.

Cheesy butter, 192.

Cheshire curd-mill, 267.

Cholera caused by germs, 95.

Cholesterin in milk, 30.

Churning, 159, 166-174; changes during, 168;
conditions influencing, 170; definition of,
159; of milk, 173; preparation of milk for,
166; temperature for, 171.

Churns, 160-166; beating, 161; description
of, 161-166; horizontal barrel, 164; prac-
tical value of, 166; qualifications of, 160-
161; of special construction, 165; swinging,
cradle, or rocking, 162-164; varieties of,
161; vertical barrel, 165; vvorking of, 161.

Citric acid in milk, 29, 30.

Cleanliness in relation to dairying, 89, 97.

Coagulation of milk, 12, 200-203; by acids,
201; by bacteria, 89; by rennet, 210-213.

Coagulum from milk, 200-203; preparation
of, 210.

Cold water cream-raising method, 114-115.

Colostrum, 34-37; ash of, 36; composition of,
35, 36; corps granuleux in, 35; corpuscles,
36; properties of, 35; specific gravity of, 36.

Coloured milk, 102.

Colouring of, butter, 177; cheese, 213.

Condensed milk, 282-286 ; composition of,
284, 285; preparation of, 283-284; proper-
ties of, 284; specific gravity of, 285; un-
sweetened, 285.

Connective tissue, 1.

Co-operative dairies, supervision of milk in, 77.

Corps granuleux, 35.

Cotswing churn, 162.

Cow-dung, bacteria in, 298.

Cows, age of, 40; feeding of, 41-48; treatment
of, 80; working of, 40.

Cradle-churns, 161, 163.

Cream, 76, 154-156; ash of, 155; composition
of, 155; condition of, 148; cooling of, 148;
outflow of, from Separator drum, 123; regu-
lation of weight of, in separator, 124; ripen-
ing of, for churning, 166; sour, churning
of, 172; specific gravity of, 155; spontaneous
souring of, 99-100; sweet, churning of, 172;
utilization of, 155; valuation of, 156.

Cream-butter, 185.

Creaming by separators, supervision of, 145-
146.

Cream -raising, 107-119; coefficient, 101;
conditions necessary for, 108; methods of,
117; older methods of, 112; by separators,
119; Swartz method of, 113.

Cream-souring, 166-168.

Cream-yielding coefficient, 118.

Curd from milk, 200-203; treatment of, be-
fore moulding, 218-221.

Curd-breaker, 219.

Curd-knives, 219.

Curd-mill, 266, 267.

Curd-stirrer, 219, 266, 267.

Curd-whey, 269.

Currents in creaming, 178.

Dairies, books for, 305-310; depai'tments of,
149; model of, 315; proper working of
separators in, 149-152; structure and
arrangement of, 314; supervision of milk
in, 77.

Dairying, economic aspects of, 296-315; rela-
tion of bacteriology to, 89-105.

Danish separator, 135.

Dead milk, 52.

Definition of milk, 1-6.

De Laval .separators, 129-131, 132.

Density of milk, 13.

Devonshire cream-raising method, 109.

Dialysis of milk, 14.

Diaphragm churn, 163.

Dishorning, 41.

Disinfectants, 45.

Distribution of milk, 61-62.

Disturbances of milk, 100.

Drum of separator, 122.

Drying-rooms for cheese, 227.

Dull butter, 192.

INDEX.

341

Edam cheese, 253-256.
Eimar centrifugal separator, 1-36.
Emmenthaler cheese, composition of, 274;
preparation of , 256-261; properties of , 260.
Enzymes, 92, 100.
Epithelial cells, 2.
Erj'throgenes bacteria lactis, 102.
Eureka butter- worker, 180.
Expansion of milk, coefficient of, 13.
Extraction of milk, 58.

Factors for calculating composition of milk,

32-34, 329-330.
Fat, determination of, in butter, 198; in

cheese, 273; in milk, 82-84.
Fat cheese, conversion of milk into, 298.
Fattening, value of milk for, 51-53.
Faults of, butter, 191-193; cheese, 241; milk,

51-53.
Feeding of cows, 41-48; influence of, on pro-
perties of butter, 191.
Fermentation processes, caused by bacteria,

90; nature of, 202; necessary for dairying,

90.
Fermented milk, 286-291.
Fibrin in milk, 30.

Firmness of butter, 191; defects in, 192.
Fission, 93.
Fission fungi, 92, 93.
Flat sugar, 293.
Food, influence of, on milk secretion, 41-48;

quantity of, to be given, 44-46.
Forces acting in separators, 152.
Formation ol milk, 6-11.
Formulae for calculating, compo.sition of milk,

32-34, 329-330; yield of butter, 310.
French margarine, composition of, 322.
Fresh butter, 185-186.

Frost, action of, on bacteria, 94; on milk, 13.
Fungi, distribution of, 93; functions of, 92.

•Galacto.se, 26.

Gammelost, 269.

Gland-basket, 2.

Glarner green cheese, 266.

Glasler, 260.

Gleed cheese-press, 225.

Globulin in milk, 15, 17.

Goat, 54.

Goats' milk, 53-55; amount of yield of, 54;
cheese from, 265; composition of, 54; pro-
jierties of, 53; specific gravity of, 55.

Grape-sugar, 293.

Grass butter, 186.
. Gravity, influence of, on creaming, 119.

Gniax de montagne, 269.

Gruyere cheese, 256.

Guaiacum, a test of milk, 12, 88.

Gussander cream-raising method, 112.

Hamburg mixed butter, compo.sition of, 322.

Hands, position of, m milking, 59.

Hand separators, 121, 126, 128, 153.

Hard cheeses, 248.

Hardening of cheese-curd, 218.

Heat, action of, on milk, 12.

Heating of cheese-vats, 214-217.

Heat units, 217.

Hehner method for butter analysis, 197.

Holstein butter-worker, 181.

Holstein ci-eam -raising method, 109, 112.

Horizontal churns, 161, 164.

Hot-air engines, 152.

Hot-iron test for cheese, 220.

Hydrolytic ferments, 203.

Hygrometer, 231.

Hypoxanthin in milk, -30.

Ice, collection and storage of, 115-117; in-
dispensable for dairying, 115; used in
cream-raising, 113.

Ice machines, 117.

Indicator for separators, 128.

Inertia of matter, 119.

Inflation of cheese, 104.

Inflow of milk into .separator-drum, 123.

Inorganic constituents of milk, 27-29.

Inspection of milk-trade, 76-77.

Intermittent sterilization, 96.

Jaurt, 294.

Karagrut, 294.

Keeping milk, 276.

Kephir, 104, 287-289; composition of, 289;

grains, 287; nature of fermentation, 288;

preparation of, 288; properties of, 287.
Keschk, 294.
Kircuma, 87.
Kneading of butter, 179; temperature for,

182.
Koettstorfer method for butter analysis, 197.
Kongen's Xytorf separator, 136.
Koumiss, 104, 289-290; composition of, 290;

preparation of, 290; properties of, 289.

Lactalbumin in milk, 15, 17.

Lactarine, 295.

Lactation periods, 39.

Lactic acid, produced by bacteria, 99.

Lactite, 295.

Lactocaramel, 26.

Lactocrit, 70, 78.

Lactoprotein, 16, 18.

Lange milch, 291.

Lardy butter, 192.

Latent heat, of milk, 13; of water, 117.

Laval, cream-cooler, 149; milk-scalder, 277.

Lawrence refrigerator, 14S.

Lazv milk, 52

Lecithin, 29, 30.

342

SCIENCE AND PRACTICE OF DAIRYING,

Lefeldt, centrifugal butter - tester, 197 ;

churns, 163; Pasteurizing apparatus, 279;

separator, 126, 127, 129.
Le reclage, 264.
Le revirage, 204.
Lever cheese-press, 226.
Light, effect of milk on, 14.
Limburg cheese, composition of, 274.
Limits of variation in composition of milk, 73.
Liquid residue from cheese manufacture, 269.
Lobules, 2.
Lower fungi, 90-93 ; distribution of, 93 ;

functions of, 92,

Mammary glands, 3.

Mares' milk, 56-57; amount of yield of, 57;
composition of, 57; properties of, 56; spe-
cific gravity of, 57.

Margarimeter, 196.

Margarine, 316-322; composition of, 322;
discovery of, 316; oils used for, 318; pre-
paration of, 317; uses of, 318.

Margarine cheese, 322-326; demand for, 323.

Melted butter, 188.

Metabiosis, 103.

Micrococcus prodigiosus, 101.

Micro-organisms, 89-105; destruction of, 105;
discovery of, 90; forms of, 91; in cheese,
102, 239-241 ; in milk, 89-105.

Milk, 1-105; adulteration of, 65-74; analysis
of, 80-88; churning of , 173; coagulation of,
12, 200 ; coefficient of expansion of, 13 ;
composition of, 30-32 ; definition of, 1 ;
density of, 13; dialysis of, 14; difficult to
churn, 53; distribution of, 61-63; factors
for calculating composition of, 32-34, 329-
3.30; fat in, determination of, 82-84; for-
mation of, 6-12; freezing of, 13; heating
of, 12; lazy or dead, 52; latent heat of, 13;
light, action of, on, 14; limits of variation
in, 73; micro-organisms in, 89-105; mineral
matter of, 27-29 ; minor constituents of,
29-30; nitrogenous matter of, 15-19; pre-
cipitation of, 16; properties of, 11-14; pur-
chase of, 77; reaction of, 11-12; refractive
point of, 14 ; relation between specific
gravity and percentage of fat and total
solids, 32-34; sale of, 63-64; sandy, 53;
secretion of, in udder, 37-39; influence of
food on, 42-44; specific gravity of, 11, 16,
31, 32; spontaneous coagulation of, 99-100;
sterilization of, 95-99 ; testing of, 66-74 ;
total solids of, composition of, 31, deter-
mination of, 81 ; treatment of, after milking,
60-61; utilization of, 296-315; value of, as
an article of sale, 63, for fattening pur-
poses, 62-63; yields, 48-51.

Milk businesses, 64-65.

Milk-butter, 185.

Milk-cakes, 282.

Milk-cisterns, 3, 4.

Milk-cows, 63.

Milk-diseases, 100-102.

Milk-fat, 19-24; composition of, 22; condition
of, 20; decomposition of, 23; determination
of, 82-84; globules in milk, number of, 21,
size of, 19; percentage of, in milk, 19; pro-
perties of, 22 ; specific gravity of, 20, 23;
solubility of, 24.

Milk-faults, 51-53; causes influencing, 52.

Milk-fehler, 100.

Milking, 58-60.

Milking machines, 58.

Milking periods, 38-39.

Milk-ivory, 295.

Milk-production, supervision of, 79.

Milk-records, 308.

Milk-scalder, 277.

Milk-sugar, 24-27, 294 ; composition of, 25,
294; decomposition of, 24; determination
of, in butter, 199, in cheese, 274, in milk,
85-86; effect of heat on, 25; preparation
of, 293; uses of, 291,

Milk-testing, 66-74.

Milk-trade, supervision of, 74-77.

Milk-warmers, 146.

Milk-yielding capacity of cows, 49-51; arti-
ficial development of, 49; conditions in-
fluencing, 49; determination of, 50; external
characteristics of, 50.

Milk-yields, 48-51 ; conditions influencing, 48.

Mineral adulterants of milk, 87.

Mineral matter of milk, 27-29.

Minor constituents of milk, 29-30.

Model of dairy, 315.

Molkensich, 259.

Moulding of cheese, 222-223.

Moulds, 92.

Multiplex separator, 126.

Musty butter, 193.

Mysost, 268; composition of, 275.

Neufchatel cheese, composition of, 274; pre-
paration of, 247.

Niszler, 260.

Nitrogen in milk, 30.

Nitrogenous matter, of cheese, determiuatiton
of, 273; of milk, determination of, 84-85;
lost in .separation of milk, 154,

Nuclein, 15, 30.

Nucleo-albumin, 17,

Nutritive ratio, 45.

Nutritive value of skim-milk, 159.

Nytorf separator, 136.

Oil-cakes, influence of, on milk production, 47.

Oily butter, 192.

Olmiitzer cheese, 274.

Oneida cheese-vat, 217.

Osmotic action of salt, 179, 227.

Ox-flesh, protein in, 159.

Oxygen in milk, 30,

INDEX.

343

Ozone reaction for boiled milk, 88.

Paracasein, 202, 236.

Paris butter, 185.

Pasteurized milk, 276-280; properties of, 277.

Pasteurizing apparatus, 278.

Pasteurizing of milk, 61, 95; effects of, 276.

Pathogenic germs, 95, 276.

Payment of milk by weight and composition,

311-313.
Pegot, 264.

Percentage composition of cows' milk, 30-32.
Petersburg butter, 185.
Petersen separator, 135.
Petroleum engines, 152.
Pigs, feeding of, with skim-milk, 157.
Piophila casei, 232.
Potato cheese, preparation of, 267.
Pottkass, 256.
Power separators, 131.

Preservatives, for butter, 199; for milk, 60.
Preserved butter, 186.
Preserved mOk, 282-286.
Pi'essing of butter, 182.
Pressing of rennet cheese, 22.3-227.
Prima weinar sparbutter, 320; composition

of, 323.
Profits from utilization of milk by different

methods, 302-305.
Properties of milk, 11-14.
Prophet's grains, 287.
Proteids, determination of, in butter, 198; in

milk, 84-85.
Protein, 15.
Ptomaines, 92.
Puffiness in cheese, 261.
Pultost, 269.
Putrefaction, caused by bacteria, 90.

Raden cheese, composition of, 274.

Rancid butter, 192.

Reaction of milk, 11-12.

Recuit, 268.

Refractive point of milk, 14,

Refrigerators, 148.

Reib cheese, 275.

Reichert method for butter analysis, 197.

Reimer creaming method, 112.

Reindeer-milk cheese, 265.

Rennet, 203-213; application of, in practice,
210-213; coagulation of milk by, 201-206;
conditions favourable for action of, 204;
determination of strength of, 206; forms
used in, 206; preparation of, 208; proper-
ties of, 205, 208; sources of, 203; tempera-
ture for coagulating by, 205; testing of, 206.

Rennet cheeses, shaping of, 221 ; from sheeps'
milk, 261; hard, 248; pressing of, 223-227;
salting of, 227; soft, 246.

Rennet powder, 206.

Rennet test for milk, 79.

Resistance to rising of fatty globules, 107.

Reverum, 264.

Ribarbe blanche, 264.

Ricotta, 268.

Ripe milk, 166.

Ripening of cheese, 102-103, 236-243; changes

in, 236; effected by micro-organisms, 102;

products of, 239.
Ripening of cream for churning, 166.
Ripening rooms for cheese, 231-233.
Rocking churns, 161, 163.
Ropy milk, 101, 287, 291.
Roquefort cheese, preparation of, 262-265.

Sale of milk, 63, 296.

Salicylic acid in milk, detection of, 87.

Salt, 178.

Salting of, butter, 178, 181; cheese, 227.

Sampling of milk, 68.

Sandy milk, 53.

Saprophytic germs, 95.

Sarcina, 102.

Schottensicht, 268.

Scoops for cheese-making, 218, 219.

Secretion of milk in udder, 37-39; influence
of food on, 42-44.

Separator butter, 185.

Separator drum, 122; inflow of milk into, 123;
milk in, 122; outflow of cream and skim-
milk from, 123; reliability of, 124; super-
vision of revolving rate of, 145.

Separator residue, 153-154; bacteria ir., 98;
composition of, 154.

Separators, 120-153; Alpha, 131-134; bal-
ance, 140; best, 141; Burmeister & Wain's,
134-137; cream-raising coefficient in, 141;
De Laval, 129-131; forces acting in, 152;
hand, 121, 126, 128, 132, 137; invention of,
120; Lefeldt, 126; multiplex, 126; power,
126-127; presently used, 126, 140; proper
working of, in dames, 149-152; value of,
141; regulation of weight of cream and
skim-milk in, 124; Victoria, 138.

Shaping -of cheese, 221-223.

Sheep, 55.

Sheep's milk, 55-56; amount of yield of, 55:
composition of, 56; properties of, 55; speci-
fic gravity of, 56.

Siberian butter, 188.

Skim-milk, 76, 156-159; ash of , 158; composi-
tion of, 158; fattening power of, 114;
nutritive value of, 159 ; outflow of, from
separator drum, 133; properties of, 156;
regulation of weight of, in separator, 124;
separator, fat in, 142; specific gravity of,
76, 156; Tises of, 157; value of, 158.

Skim-milk cheese, 275.
Skimming-tnbes, 124.
Slimy milk, 101.
Soapy butter, 193.
Soft chee-ses, 246.

SCIENCE AND PRACTICE OF DAIRYING,

Sourers, 167.

Souring liquid, preparation of, 99, 167.

Sour-milk, 188-1S9.

Sour-milk cheese, 266-268; composition of,

275.
Soxhlet's fat estimation method, 70.
Spaltpilz, 101.

Specific gravity of butter, 194.
Specific gravity of milk, 11, 16, 31, 72, 76;

determination of, 68; relation between, and

percentage of total solids and fat, 32-34,

329.
Specific heat, of milk, 13; of water, 117.
Spontaneous coagulation of milk, 99-100.
Spontaneous souring of cream, 99-100.
Spores, 94.

Starch in milk, detection of, 88.
Steam for separators, 152.
Sterihzation of milk, 95-99; effects of, 95;

intermittent, 96; temperature for, 96.
Sterilized unthickened milk, 280-282.
SteriHzing apparatus, 281.
Stirrers for cheese-making, 218, 219.
Structure and arrangement of dairies, 314.
Stubble butter, 186.
Sugar-sand, 293.
Sulphates in milk, 30.
Sulphocyanates in milk, 30.
Summer butter, 186.

Supervision of milk-trade in towns, 74^77.
Surprim, 269.

Swartz's cream-raising method, 113.
Sweet-cream churning, 160, 172.
Sweet-milk churning, 160.
Swinging churns, 161, 163.
Swiss butter-worker, ISO.
Swiss lever-press, 275.
Symbiosis. 101.

Table butter, 185.

Tables for, calculating, total solids from per-
centage of fat and specific gravity, 334-336;
specific gravity of total solids of milk, 337;
correcting temperature, 331 ; regulating
separation of milk, 157.

Tallowy butter, 192.

Tea butter, 185.

Teats of cows, 4-7.

Temperature for, churning, 171-172; cream-
raising, 108, 111; milk separation, 146.

Testing of milk, 66-74,

Thickened milk, 284,

Thranen cheese, 256.

Tin-foil for cheese packing, 243.

Total solids of milk, 31-32; composition of,
31; determination of, 81; specific gravity
of, 12.

Toxalbumin, 92.

Treatment of milk after milking, 60-61.

Trimethylamine, 102.

Tuberculosis caused by germs, 95,

Tunica propria, 3.

Two-in-one double cheese-press, 224,

Typhus, caused by germs, 95.

Tyrothrix, 100.

Udder, 1-5; secretion of milk in, 37-39.

Unit of heat, 117.

Unsweetened condensed milk, 285; composi-
tion of, 286.

Unthickened sterilized milk, 280-282.

Urea in milk, 30.

Utensils necessary for cheese preparation,
214.

Utilization of milk, 296-315.

Vacuum-pan for condensing milk, 283.

Vegetative cells, 93.

Vertical churns, 161, 165.

Vessels for, cream-raising, 112; milk, 62, 105,

Victoria churns, 163, 164.

Victoria separators, 138-139,

Vinegar from whey, 270.

Volatile fatty acids in butter, 196.

Vorbruch, 187, 269,

"Warmers for milk separators, 146.

Water, determination of, in butter, 197;

cheese, 273; milk, 81.
Weighing of milk, machine for, 306, 307,
Whey, 269-270; composition of, 269,
Whey butter, 187, 258, 269,
Whey champagne, 270,
Whey cream, 258.
Whey protein, 202,
Whey punch, 270.
Winches for dairies, 152-153,
Winter butter, 186.
Woody butter, 192.
Working of, butter, 179, 182-183; cows, 40.

Yeasts, 92.

Yield of, butter, 184; cheese, 270; milk, 48-
51 ; conditions influencing, 48.

Ziger, 268; composition of, 275.
Ziger cheese, 258, 268.
Zoogloa bacteria, 101,

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