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Full text of "The book of the dairy : a manual of the science and practice of dairy work"




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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 

University of British Columbia Library 



http://www.archive.org/details/bookofdairymanuaOOflei 



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 



reason to expect that this development of dairying in New Zealand 
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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 

a 



^^^ ./ 



■""^^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. 



31 



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 (Ts ix + 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 



36 



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 


to 


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. 


lbs. 


lbs. 


lbs. 


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 



54 



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 

7_ 

100-00 

14-5% 



SHEEP S MILK. 



55 



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.) 



56 



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. 



59 



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. 



61 



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. 



62 



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. 



63 



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 

s 

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 

s 

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. 



70 



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 



86 



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. 



91 



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 

60 

100 

250 

400 



The Cost 



of 
Separator. 



M. 

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 : — 



i 

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 

50 


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.) 



f 

'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 A 
B 
X 1 

X2 


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;:= , 

R 



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. 



U9 



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 






J2 






OQ 






•luoo'a JO 

ajiUKjadiuax 


.ipoippopip 1 <p <p 
^ CO 6o 1-- oi oi 6o ii io 6i 

■-H O 


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 


o 


lu: - Cl CO 4l (Tt) r^ 4? f^3 

ct-crjGOoocooooooci 


CD 

: <^ 
■ 6^ 

00 


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 


CO 

: 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 

o o 

(M^CO 
CO 


Temperature 

•c. 




csmeoincoco-^iM 

a> r-l>-l,-lr-(i-lr-li— 1 

5 


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 


it 


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, ... 


21 


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 


31 


3-2 


1-2 


Milk-sugar, 


4-5 


4-6 


4-8 


2-2 


Ash, 


0-6 


0-6 


0-7 


01 




100-0 


100-0 


100-0 


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. 


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 


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 


100-00 


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 


100-00 


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 


100-0 


100-0 


100-0 


100-0 


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 


47 




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 



^r 




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 


)j 


Nitrogenous matter, 


17-806 


13-61 „ 26-50 


)j 


Milk-sugar, 


15-403 


12-50 „ 17-75 


n 


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 


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 


5> 


•40 


>> 


•63 


)) 


12-96 


marks. 


1-25 


>j 


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 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^ - sxsH t-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 

s 

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, 

t 

m= J . 

6' 

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 

s 

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. 



F. 


C. 


F. 


C. 


F. 


C. 


F. 


C. 


F. 


C. 


32 


0-00 


69 


20-56 


106 


41-11 


143 


61-67 


180 


82-22 


33 


0-56 


70 


21-11 


107 


41-67 


144 


62-22 


181 


82-78 


34 


1-11 


71 


21-67 


108 


42-22 


145 


62-78 


182 


83-33 


35 


1-67 


72 


22-22 


109 


42-78 


146 


63-33 


183 


83-89 


36 


2-22 


73 


22-78 


110 


43-33 


147 


63-89 


184 


84-44 


37 


2-78 


74 


23-33 


111 


43-89 


148 


64-44 


185 


85-00 


38 


333 


75 


23-89 


112 


44-44 


149 


65 00 


186 


85-56 


39 


3-89 


76 


24-44 


113 


45-00 


150 


65-56 


187 


86-11 


40 


4-44 


77 


25-00 


114 


45-56 


151 


66-11 


188 


86-67 


41 


5-00 


78 


25-56 


115 


46-11 


152 


66-67 


189 


87-22 


42 


5-56 


79 


26-11 


116 


46-67 


153 


67-22 


190 


87-78 


43 


6-11 


80 


26-67 


117 


47-22 


154 


67-78 


191 


88-33 


44 


6-67 


81 


27-22 


118 


47-78 


155 


68-33 


192 


88-89 


45 


7-22 


82 


27-78 


119 


48-33 


156 


68-89 


193 


89-44 


46 


7-78 


83 


28-33 


120 


48-89 


157 


69-44 


194 


90-00 


47 


8-33 


84 


28-89 


121 


49-44 


158 


70-00 


195 


90-56 


48 


8-89 


85 


29-44 


122 


50-00 


159 


70-56 


196 


91-11 


49 


9-44 


86 


30-00 


123 


50-56 


160 


71-11 


197 


91-67 


50 


10-00 


87 


30-56 


124 


51-11 


161 


71-67 


198 


92-22 


51 


10-56 


88 


31-11 


125 


51-67 


162 


72-22 


199 


92-78 


52 


11-11 


89 


31-67 


126 


52-22 


163 


72-78 


200 


93-33 


53 


11-67 


90 


32-22 


127 


52-78 


164 


73-33 


201 


93-89 


54 


12-22 


91 


32-78 


128 


53-33 


165 


73-89 


202 


94-44 


55 


12-78 


92 


33-33 


129 


53-89 


166 


74-44 


203 


95-00 


56 


13-33 


93 


33-89 


130 


54-44 


167 


75-00 


204 


95-56 


57 


13-89 


94 


34-44 


131 


55-00 


168 


75-56 


205 


96-11 


58 


14-44 


95 


35-00 


132 


55-56 


.169 


76-11 


206 


96-67 


59 


15-00 


96 


35-56 


133 


56-11 


170 


76-67 


207 


97-22 


60 


15-56 


97 


36-11 


134 


56-67 


171 


77-22 


208 


97-78 


61 


16-11 


98 


36-67 


135 


57-22 


172 


77-78 


209 


98-33 


62 


16-67 


99 


37-22 


136 


57-78 


173 


78-33 


210 


98-89 


63 


17-22 


100 


37-78 


137 


58-33 


174 


78-89 


211 


99-44 


64 


17-78 


101 


38-33 


138 


58-89 


175 


79-44 


212 


10000 


65 


18-33 


102 


38-89 


139 


59-44 


176 


80-00 






66 


18-89 


103 


39-44 


140 


60-00 


177 


80-56 






67 


19-44 


104 


40-00 


141 


60-56 


178 


81-11 






68 


20-00 


105 


40-56 


142 


61-11 


179 


81-67 













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p t^ r- 00 p p 

^ ^ ^ ,L( ^ (i,l 

(M (M (M (M <M (M 



r-l ».1 CO 

(k (k cq 

CM <M tN 



-fi ip p 00 
fiq cq lyi (ji 

(M »1 G<l G^l 



ps^i-^poopfNTfipqoi^coipi-^pco 
cococoMco-^Tt<-t<-^T}<ibibibibiDi> 

(5q(NCM<M(M(MC<lG<l(N(NCM(MCM(MCMCM 



1^ 1^ r^ 00 Oi O 

66066.^ 



^3-t<ippgop(M-:+'=cioo 
c^^(^^(^^(^^(^^c^^cMG<lCM(^^cMG<^(^^ 



CMTj<pQ0rHCOipl;^pG^ 
(?lG<)(>)(>lCMCOfOCOCOCO--t<-^<Tt<Tt<-fib 
CM(M!MCN(M(MtM<»CM(N0<|(M!MCMi5<ICM 



K5 p 



r- 1^ i~- 00 p p 

C5 Oi C5 05 C5 O 



r7H(MM-^ipp00p7-l^pCpp(>]-rt<pgOp(yiT)ip0OrH 

ooooooi'^'— I'-Hr^T^oqoqcktkckrococococO'^ 

CMGs|(>4G<lCM(?1CMCMCM(MOI(MCMG<)CMtMtMG<l(MCM(MCMCM 



1;- i^ 

00 c» 



l^-^ 00 CO p p p 

00 00 00 00 C5 o: 



r-H Oq CO 

Oi C5 05 



Tj* ip p GO 
Oi Ci Ci Oi 



prHcoipr^prHCOipi^prHeoipt^O 

(MCMCMCMCMtMCHtMcqcMCNCMCMCMtNoq 



oogoooppprHr-Hcqco-jfippr^oo 
i^ t- r^ i'^ r'^ (X) i) oD o) 00 00 00 do 00 00 



prHCOipt~P7-lC0ipi>'Pr-IC0ipr~p 

050iC505C5C5COOOO^^'— it-Hi-Tinq 
^i-Hi— i,-H,-<rHCNCM(MCMCMCMCM(MCM(M 



pppppr^-T^iTHG^ICOTfippr^qO 
lio i> io t^ 1^ r- r^ t~ t^ i^ i ^ t^ 1"^ i-^ r^ 



PrHCOipt'-prHCOipr-pr-lfOipt^P 

Qo6ooo<i)6oooc5d5diOiC5 0oor^ 

i-Hrlr-HrHrHi— I,— (i-li— I,— i,-iCMOqCMCMI» 



ppPpprH,— lnH(>100rt<ippt^0C 

ibibibi5ix>iDi)i>i:)i3i:ii>cboic 



pT-iCOipi-^prTHCOipr^prT-iCOipi^^P 

I'^-i^i^t^i^-i^ooooooooooosoiososo 



ppppprH-^i^^^icOTfippr^oo 
■rti-^-fibibibibibibibibibibibib 



pr-icoipr^p7-<coipi^pi7HCOipr^05 
Q^iiccocbi-^r^r^r-i'^QOaOQOoooo 



PpPPP7Hr-Hr-H(NM7Pippt^00p^(M-HpC0p(>l-7)'p(»p<>)7**P<» 

Mf:'co-^-rf<-^<-^-^<-^-^<-^4f-^f'^'^<ibibibibibibiDiDiiocbi"^r~i"-^t^^ 



ppppp'7-i7H>7^(V<lC07tiippr~tppi-HfM-^p(»pc^-^pQOp(>)rt<pQO 

(i<i6^a^icofofoficoftwfoftcofico--f'-t-rt<-t'-#rt<o 



01 CO -t lO CO 1^ 00 c: o 



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. 



o 



O>-'<Mf0'*OOl^XC5 






,(>,C0^OQ0O(M:t=p05C?lT*'P=P':'T''^?^I?SS 









s^ 



Eh :g 



■Si 

s 






'^ g^ ^^ 55 §^ ^ ^ ^ S S §^ S ?. S^l^l^^l^^^l^^il^i^!^^ 



ooQOQoa3Cip^7-.r'?'?^:^v-^^?^?i:SS£:S 









C0CDQ0Q0C5O'--''--i 



liMlllilliiMMIilMMMi 



^j„rc^-t'ooi:-ooa:Cr-'Oi^<:oxo57Hfoipr-g>.:Hco 

I S^N \> » -W •• .J .* , . . • • ••*_**•«,;■, _u _u -^ —« -4< .--v i-"- 



iiiliiiii^iig^^jg^s^s^g^^g^s^^^^^"^^^^^ 



,_,_l,_l,_o^^fOo■^'^!t07t"p^^^~90 



,-^(^^^ococ;'-|fO"pt-s:7-'fOO^- 






g i g i g g ^ g g ^ g ^ ^ ° gj ^ ^ ^^ ^^ ^ ^ ^^ '^^ ^ ^^ ^^ ^^ ^' ^ ^^ ^ 



C50505a502222S22222S§ScN55§5ScMCMCM o) CM oi a-i ^m g-i 



ia)(3ocb<X)a)(X)a)Qooooca)co2 2 2222S22S§§c5G5o^»5CM(N 



O 



^^.^^^t^,?,t-f^t^i_;t^t^r:;t:;2S2222222 2 2 2 g a a^ i 



iCMCC'*»001>'XC5C 



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/ 


/ 


1-2 x/ 


/ 


1-2 x/ 


/ 


1-2 x/ 


/ 


1-2 x/ 




100 


1-2(H) 


1-50 


1-800 


200 


2-400 


2-50 


3-000 


3-00 


3-600 






01 


1-212 


51 


1-812 


01 


2-412 


51 


3-012 


01 


3-612 




02 


1-224 


52 


1-824 


02 


2-424 


52 


3-024 


02 


3-624 


05 O 




03 


1-236 


53 


1-836 


03 


2-436 


53 


3-036 


03 


3-636 






04 


1-248 


54 


1-848 


04 


2-448 


54 


3-048 


04 


3-648 






05 


1-260 


55 


1-860 


05 


2-460 


55 


3-060 


05 


3-660 






06 


1-272 


56 


1-872 


06 


2-472 


56 


3-072 


06 


3-672 


O 




07 


1-284 


57 


1-884 


07 


3-484 


57 


3-084 


07 


3-684 


X O 




08 


1-296 


58 


1-896 


08 


2-496 


58 


3-096 


08 


3-696 


6 




09 


1-308 


59 


1-908 


09 


2-508 


59 


3-108 


09 


3-708 






liO 


1-320 


1-60 


1-920 


2-10 


2-520 


260 


3-120 


310 


3-720 


CO 

o 
t» o 




11 


1-332 


61 


1-932 


11 


1 2-532 


61 


3132 


11 


3-732 




12 


1-344 


62 


1-944 


12 


2-544 


62 


3-144 


12 


3-744 


6 




13 


1-356 
1-368 


63 

64 


1-956 
1-968 


13 
14 


2-556 
2-568 


63 
64 


3-156 
3-168 


13 
14 


3-756 
3-768 






14 






15 


1-380 


65 


1-980 


15 


2-580 


65 


3-180 


15 


3-780 


r^ 




16 


1-392 


66 


1-992 


16 


2-592 


66 


3-192 


16 


2-792 


CD O 




17 


1-404 


67 


2-004 


17 


2-604 


67 


3-204 


17 


3-804 


b 




18 


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 






19 


CD 

O 

iC o 

6 




1-20 


1-440 


1-70 


2-040 


2-20 


2-640 


2-70 


3-240 


3 20 


3-840 




21 


1-452 


71 


2-052 


21 


2-652 


71 


3-252 


21 


3-852 




22 


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 






23 






24 


1-488 


74 


2-088 


24 


2-688 


74 


3-288 


24 


3-888 


lO 




25 


1-500 


75 


2-100 


25 


2-700 


75 


3-300 


25 


3-900 


o 
•* o 




26 


1-512 


76 


2-112 


26 


2-712 


76 


3-312 


26 


3-912 


6 




27 


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 






28 






29 


1-548 


79 


2-148 


29 


2-748 


79 


3-348 


29 


3-948 


o 

CO C 

6 




130 


1-560 


180 


2-160 


2-30 


2-760 


280 


3-360 


330 


3-960 




31 


1-572 


81 


2-172 


31 


2-772 


81 


3-372 


31 


3-972 




32 


1-584 


82 


2-184 


32 


2-784 


82 


3-384 


32 


3-984 






33 


1-596 


83 


2-196 


33 


2-796 


83 


3-396 


33 


3-996 


fN 




34 


1-608 


84 


2-208 


34 


2-808 


84 


3-408 


34 


4-008 


CN O 




35 


1-620 


85 


2-220 


35 


2-820 


85 


3-420 


35 


4-020 


6 




36 


1-632 

1-644 


86 

87 


2-232 

2-244 


36 
37 


2-832 
2-844 


86 

87 


3-432 

3-444 


36 
37 


4-032 
4-044 






37 






38 


1-656 


88 


2-256 


38 


2-856 


88 


3-456 


38 


4-056 


o 




39 


1-668 


89 


2-268 


39 


2-868 


89 


3-468 


39 


4-068 


6 




1-40 


1-680 


1-90 


2-2S0 


2-40 


2-880 


290 


3-480 


340 


4-080 




41 


1-692 


91 


2-29:i 


41 


2-892 


91 


3-492 


41 


4-092 


s^_ • 




42 


1-704 


92 


2-304 


42 


2-904 


92 


3-504 


42 


4-104 


tl-H 






43 


1-716 


93 


2-316 


43 


2-916 


93 


3-516 


43 


4-116 


ai 






44 


1-728 


94 


2-328 


44 


2-928 


94 


3-528 


44 


4-128 


5 






45 


1-740 


95 


2-340 


45 


2-940 


95 


3-540 


45 


4-140 








46 


1-752 


96 


2-352 


46 


2-952 


96 


3-552 


46 


4-152 








47 


1-764 


97 


2-364 


47 


2-964 


97 


3-564 


47 


4-164 


O 






48 


1-776 


98 


2-376 


48 


2-976 


98 


3-576 


48 


4-176 


^:§ 




49 


1-788 


99 


2-388 


49 


2-988 


99 


3-588 


49 


4-188 


g-i 




150 


1 -800 


200 


2-400 


250 


3-000 1 


300 


3-600 


3-50 


4-200 


Pm 


1 











TABLE 


IVa.- 


-{Continued). 








/ 


1-2 x/ 


/ 


1-2 x/" 


/ 


1-2 x/ 


f 


1-2 x/ 


/ 


1-2 x/ 




3-50 


4-200 


4-00 


4-800 


4-50 


5-400 


500 

of 


6-000 


5-50 


6-600 






5i 


4-212 


01 


4-812 


51 


5-412 


6-012 


51 


6-612 




52 


4-224 


02 


4-824 


52 


5-424 


02 


6-024 


52 


6-624 


C5 O 




53 


4-236 


03 


4-836 


53 


5-436 


03 


6-036 


53 


6-636 


C 




54 


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 






55 






56 


4-272 


06 


4-872 


56 


5-472 


06 


6-072 


56 


6-672 


C 




57 


4-284 


07 


4-884 


57 


5-484 


07 


6-084 


57 


6-684 


X p 




58 


4-296 


08 


4-896 


58 


5-496 


08 


6-096 


58 


6-696 


o 




59 


4-308 


09 


4-908 


59 


5-508 


09 


6-108 


59 


6-708 






360 


4-320 


4-10 


4-920 


4-60 


5-520 


5-10 


6-120 


5-60 


6-720 


00 




6i 


4-332 


11 


4-932 


61 


5-532 


11 


6-132 


61 


6-732 




62 


4-344 


12 


4-944 


62 


5-544 


12 


6-144 


62 


6-744 


o 




63 


4-356 
4-368 


13 
14 


4-956 
4-968 


63 
64 


5-556 
5-568 


13 

14 


6-156 
6-168 


63 

64 


6-756 
6-768 






64 






65 


4-380 


15 


4-980 


65 


5-580 


15 


6-180 


65 


6-780 


r^ 




66 


4-392 


16 


4-992 


66 


5-592 


16 


6-192 


66 


6-792 


CO o 




67 


4-404 


17 


5-004 


67 


5-604 


17 


6-204 


67 


6-804 


o 




68 


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 






69 


CD 
O 

6 




3-70 


4-440 


4-20 


5-040 


4-70 


5-640 


5-20 


6-240 


5-70 


6-840 




71 


4-452 


21 


5-052 


71 


5-652 


21 


6-252 


71 


6-852 




72 


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 






73 






74 


4-488 


24 


5-088 


74 


5-688 


24 


6-288 


74 


6-888 


«c 




75 


4-500 


25 


5-100 


75 


5-700 


25 


6-300 


75 


6-900 


Tt< O 




76 


4-512 


26 


5-112 


76 


5-712 


26 


6-312 


76 


6-912 


6 




77 


4-524 


27 


5-124 


77 


5-724 


27 


6324 


77 


6924 






78 


4-536 


28 


5-136 


78 


5-736 


28 


6-336 


78 


6-936 






79 


4-548 


29 


5-148 


79 


5-748 


29 


6-348 


79 


6-948 


CO 5 
6 




380 


4-560 


4-30 


5-160 


4-80 


5-760 


5-30 


6-360 


5-80 


6-960 




81 


4-572 
4-584 


31 
32 


5-172 
5-184 


81 

82 


5-772 

5-784 


31 
32 


6-372 

6-384 


81 

82 


6-972 
6-984 




82 






83 


4-596 


33 


5-196 


83 


5-796 


33 


6 396 


83 


6-996 


(71 




84 


4-608 


34 


5-208 


84 


5-808 


34 


6-408 


84 


7-008 


(N O 




85 


4-620 


35 


5-220 


85 


5-820 


35 


6-420 


85 


7-020 


6 




86 


4-632 


36 


5-232 


86 


5-832 


36 


6-432 


86 


7032 






87 


4-644 


37 


5-244 


87 


5-844 


37 


6-444 


87 


7-044 






88 


4-656 


38 


5-256 


88 


5-856 


38 


6-456 


88 


7-056 


o 




89 


4-668 


39 


5-268 


89 


5-868 


39 


■6-468 


89 

5-90 

91 


7-068 


6 




390 


4-680 


4-40 


5-280 


490 


5-880 


5-40 


6-480 


7-080 




91 


4-692 


41 


5-292 


91 


5-892 


41 


6-492 


7-092 


s^ - 




92 


4-704 


42 


5-304 


92 


5-904 


42 


6-504 


92 


7104 


o : 




93 


4-716 


43 


5-316 


93 


5-916 


43 


6-516 


93 


7-116 


CO : 




94 


4-728 


44 


5-328 


94 


5-928 


44 


6-528 


94 


7-128 


-^ 




95 


4-740 


45 


5-340 


95 


5-940 


45 


6-540 


95 


7-140 


c ; 




96 


4-752 


46 


5-352 


96 


5-952 


46 


6-552 


96 


7-152 


1 : 




97 


4-764 


47 


5-364 


97 


5-964 


47 


6-564 


97 


7-164 


c • 




98 


4-776 


48 


5-376 


98 


5-976 


48 


6-576 


98 


7-176 


'-U ^' 




99 


4-788 


49 


5-388 


99 


5-988 


49 


6-588 


99 


7-188 


l- 




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. 



s. 

Thou- 


2-665 X fl 


S. 

Thou- 


2-665 x^? 


s. 

Thou- 


2-665 X ^^ 


S. 

Thou- 


2-665 x^ 


S. 

Thou- 


2-665 x'i 


sandths 


s 


sandths 


s 


sandths 


6' 


sandths 


s 


sandths 


s 


190 


4-967 


240 


6-246 


29-0 


7-511 


340 


S-763 


39^ 


10-003 


1 


4-994 


1 


6-271 


1 


7-536 


1 


8-788 


1 


10-028 


2 


5-021 


2 


6-297 


2 


7-561 


2 


8-813 


2 


10-053 


3 


5-047 


3 


6-322 


3 


7-586 


3 


8-838 


3 


10-077 


4 


5-072 


4 


6-348 


4 


7-611 


4 


8-863 


4 


10-102 


5 


5-098 


5 


6-373 


5 


7-636 


5 


8-888 


5 


10-127 


6 


5-122 


6 


6-398 


6 


7-662 


6 


8-912 


6 


10-151 


7 


5-149 


7 


6-424 


7 


7-687 


7 


8-937 


7 


10-176 


8 


5-173 


8 


6-449 


8 


7-712 


8 


8-962 


8 


10-201 


9 


5-199 


9 


6-475 


9 


7-737 


9 


8-987 


9 


10-225 


200 


5-225 


25-0 


6-500 


30-0 


7-762 


350 


9-012 


40-0 


10-250 


1 


5-251 


1 


6-525 


1 


7-787 


1 


9-037 






2 


5-277 


2 


6-551 


2 


7-812 


2 


9-062 






3 


5-302 


3 


6-576 


3 


7-837 


3 


9-087 


TS -« 1 » m 


4 


5-328 


4 


6-601 


4 


7-863 


4 


9-111 


1 


X j3 


5 


5-353 


5 


6-627 


5 


7-888 


5 


9-136 


1 

d 




6 


5-379 


6 


6-652 


6 


7-913 


6 


9-161 


<N -*■ 


7 


5-405 


7 


6-677 


7 


7-938 


7 


9-186 




-S ^ 


8 


5-430 


•8 


6-703 


8 


7-963 


8 


9-211 


■cS 




9 


5-456 


9 


6-728 


9 


7-988 


9 


9-236 


CO 
o 




210 


5-481 


260 


6-753 


31-0 


8-013 


360 


9-261 


G TO CO 


1 


5-507 


1 


6-779 


1 


8-038 


1 


9-285 


"o IS "o 


2 


5-532 


2 


6-804 


2 


8-063 


2 


9-310 


o 


3 


5-558 


3 


6-829 


3 


8-088 


3 


9-335 


'a 




4 


5-584 


4 


6-855 


4 


8-113 


4 


9-360 




T -gfo 


5 


5-609 


5 


6-880 


5 


8-138 


5 


9-385 


-£« 


CO ^ -g 


6 


5-635 


6 


6-905 


6 


8-163 


6 


9-409 


U 




7 


5-660 


7 


6-930 


7 


8-188 


7 


9-434 


i 


> 'wo; 


8 


5-686 


8 


6-956 


8 


8-213 


8 


9-459 


.2 


1 o S 


9 


5-711 


9 


6-981 


9 


8-239 


9 


9-484 


c3 




220 


5-737 


27-0 


7-006 


32-0 


8-264 


370 


9-509 


o o> 


1 


5-762 


1 


7 032 


] 


8-289 


1 


9-533 


^ •'^ be 

-*-3 &JD « 


2 


5-788 


2 


7-057 


2 


8-314 


2 


9-558 




■^ .S w 


3 


5-813 


3 


7-082 


3 


8-339 


3 


9-583 






4 


5-839 


4 


7-107 


4 


8-364 


4 


9-608 


-Q 


2 a^ 


5 


5-864 


5 


7133 


5 


8-389 


5 


9-632 




tlj M CD 


6 


5-890 


6 


7-158 


6 


8-414 


6 


9-657 




-^ 8^ 


7 


5-915 


7 


7-183 


7 


8-439 


7 


9-682 




3 s- c 


8 


5-941 


8 


7-208 


8 


8-464 


8 


9-707 


M 
1 




9 


5-966 


9 


7-234 


9 


8-489 


9 


9-732 


1 

P3 


S s 

0) 3 3 


230 


5-992 


28-0 


7-259 


330 


8-514 


38 


9-756 


r-< a> h 


1 


6017 


1 


7-284 


1 


8-539 


1 


9-781 


.5 ^ (U 


2 


6-042 


2 


7-309 


2 


8-563 


2 


9-806 


O 




3 


6-068 


3 


7-334 


3 


8-588 


3 


9-830 


03 


girt 


4 


6-093 


4 


7-360 


4 


8-613 


4 


9-855 


O 


03 -^ 03 

2 '^ -S 


5 


6-119 


5 


7-385 


5 


8-638 


5 


9-880 




01 .S c 


6 


6-144 


6 


7-410 


6 


8-663 


6 


9-904 


s 




7 


6-170 


7 


7-435 


7 


8-688 


7 


9-929 


p 


to <p x) 


8 


6-195 


8 


7-460 


8 


8-713 


8 


9-954 




5 .2'i 


9 


6-221 


9 


7-485 


9 


8-738 


9 


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. 



s 

Thou- 
sandths 


s 


S 

Thou- 
sandths 


s 


s 

Thou- 
sandths 


s 


S 

Thou- 
sandths 


s 


S 

Thou- 
sandths 


s 


190 


1-864 


24-0 


2-344 


290 


2-818 


340 


3-288 


390 


3-754 


1 


1-874 


1 


2-353 


1 


2-828 


1 


3-298 


1 


3-763 


2 


1-884 


2 


2-363 


2 


2-837 


2 


3-307 


2 


3-772 


3 


1-894 


3 


2-372 


3 


2-847 


3 


3-316 


3 


3-781 


4 


1-903 


4 


2-382 


4 


2-856 


4 


3-326 


4 


3-791 


5 


1-913 


5 


2-391 


5 


2-865 


5 


3-335 


5 


3-800 


6 


1-922 


6 


2-401 


6 


2-875 


6 


3-344 


6 


3-809 


7 


1-932 


7 


2-410 


7 


2-884 


7 


3-354 


7 


3-818 


8 


1-941 


8 


2-420 


8 


2-894 


8 


3-363 


8 


3-828 


9 


1-951 


9 


2-429 


9 


2-903 


9 


3-372 


9 


3-837 


200 


1-961 


25-0 


2-439 


300 


2-913 


350 


3-382 


400 


3-846 


1 


1-970 


1 


2-44y 


1 


2-922 


1 


3-391 






2 


1-980 


2 


2-458 


2 


2-931 


2 


3-400 






3 


1-990 


3 


2-468 


3 


2-941 


3 


3-410 


^% 


a> 


4 


1-999 


4 


2-477 


4 


2-950 


4 


3-419 


> "x. 




5 


2-009 


5 


2-487 


5 


2-960 


5 


3-428 


Id-^ 


■rf 


6 


2-018 


6 


2-496 


6 


2-969 


6 


3-438 


u " 


i 


7 


2-028 


7 


2-506 


7 


2-979 


7 


3-447 


C£3 C 
'o „ 




8 


2-038 


8 


2-515 


8 


2-988 


8 


3-456 






9 


2-047 


9 


2-525 


9 


2-997 


9 


3-466 


c3 ^~ 


^ 


210 


2-057 


260 


2-534 


31-0 


3-007 


36-0 


3-475 


(P CO 


1 


2-066 


1 


2-544 


1 


3016 


1 


3-484 


'T3 CO 
• - CO 


2 


2-076 


2 


2-553 


2 


3-026 


2 


3-494 




^ <D 


3 


2-086 


3 


2-563 


3 


3035 


3 


3-503 


1^ 


^ -^ 


4 


2-095 


4 


2-572 


4 


3-044 


4 


3-512 




1 - 


5 


2-105 


5 


2-582 


5 


3 054 


5 


3-521 




CO ^a 


6 


2-114 


6 


2-591 


6 


3-063 


6 


3-531 


CO '^ 




7 


2-124 


7 


2-601 


7 


3-073 


7 


3-540 


■?* T-H 


(u .2 


8 


2-133 


8 


2-610 


8 


3-082 


8 


3-549 


£3 (N 

'~' CO 


-fi ,-, 


9 


2-143 


9 


2-620 


9 


3091 


9 


3-559 


2 3 


-o -S- 


220 


2-153 


27-0 


2-629 


320 


3-101 


37-0 


3-568 




1 


2-162 


1 


2-638 


1 


3-110 


1 


3-577 


s § 


2 


2-172 


2 


2-648 


2 


3-120 


2 


3-587 


""o "^ 


o _ 

to (4 


3 


2-181 


3 


2-657 


3 


3-129 


3 


3-596 


" >. 3 -2 


4 


2-191 


4 


2-667 


4 


3-138 


4 


3-605 




5 !> 


5 


2-200 


5 


2-676 


5 


3-148 


5 


3-614 


o J 


a) ■g 


6 


2-210 


6 


2-686 


6 


3-157 


6 


3-624 




■" o 


7 


2-220 


7 


2-695 


7 


3-166 


7 


3-633 




1 .^ 


8 


2-229 


8 


2-705 


8 


3176 


8 


3-642 


M O. tS > 
Is— ?* 


9 


2-239 


9 


2-714 


9 


3-185 


9 


3-652 


1 S-i 

\-> CO 

§2 




230 


2-248 


28-0 


2-724 


330 


3-195 


380 


3-661 




1 


2-258 


1 


2-733 


1 


3-204 


1 


3-670 




2 


2-267 


2 


2-743 


2 


3-213 


2 


3-679 


^ a 


g M 


3 


2-277 


3 


2-752 


3 


3-223 


3 


3689 


00 ^ 


•2 ^ 


4 


2-286 


4 


2-762 


4 


3-232 


4 


3-698 


o ^ 


' =^ *!, 


5 


2-296 


5 


2-771 


5 


3-241 


5 


3-707 


la 


o c^ 


6 


2-306 


6 


2-780 


6 


3-251 


6 


3-717 


F-H CO 

T" OS 


7 


2-315 


7 


2-790 


7 


3-260 


7 


3-726 


o| 


CO 

II .2 


8 


2-325 


8 


2-799 


8 


3-269 


8 


3-735 




9 


2-334 


9 


2-809 


9 


3-279 


9 


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. 



p 


m 


P 


m 


P 


Ml 


P 


VI 


P 


m 





1-601 


10 


1-493 


20 


1-399 


30 


1-316 


40 


1-242 


1 


1-589 


11 


1-483 


21 


1-390 


31 


1-308 


41 


1-236 


2 


1-578 


12 


1-473 


22 


1-382 


32 


1-301 


42 


1-229 


3 


1-567 


13 


1-463 


23 


1-373 


33 


1-293 


43 


1-222 


4 


1-556 


14 


1-454 


24 


1-365 


34 


1-286 


44 


1-215 


5 


1-545 


15 


1-444 


25 


1-356 


35 


1-278 


45 


1-209 


6 


1-534 


16 


1-435 


26 


1-348 


36 


1-271 


46 


1-202 


7 


1-524 


17 


1-426 


27 


1-340 


37 


1-264 


47 


1-196 


8 


1-513 


18 


1-417 


28 


1-332 


38 


1-256 


48 


1-189 


9 


1-503 


19 


1-408 


29 


1-324 


39 


1-249 


49 


1-183 


10 


1-493 


20 


1-399 


30 


1-316 


40 


1-242 


50 


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 
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 
00001968 
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. 



su 



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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