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A OO A Te TS TG Te OT pT TOO See eo a ae aromas Smowecmmentpnenenpneeetipeeaaeeeenagine eee epee ee RT AOA Keoeeneenvennbpesavelvanennastnsarean-ainveen-tseyenanpanane-ciassecaostn=sh bat suan=nsiesn=nateesnensuesesunereepaseeotemepasenpmrarereseseemmnneeeeosersieetarnemee ees some orn meee nN a aN aa ea aa pane ENORMITY eG Oe IE OTT ~ aan ee ere enn ee ee ee ey eee nep ape nenenn enone eee = Soraptoestareanerncprvanstenneast-a-sesentoann ieee peenscsionemasnsnioascvessooeesinononsieeieeneneeeeeeeeeeee eee Te en a SS. ae eeeeeeeeeeaeaeoeoese=®=®= Ea oo OOOO EE AUTH | | | | } i Class J Book = A ale tt ae Copyright N° COPYRIGHT DEPOSFr TEXT BOOK OF MILK HYGIENE BY DR. WILLIAM ERNST Official Veterinarian and Director of the Royal Milk Control Station at Munich AUTHORIZED TRANSLATION WITH ANNOTATIONS AND REVISIONS BY DR. JOHN R. MOHLER, A. M., V. M. D. Chief of Pathological Division, United States Bureau of Animal Industry AND DR. ADOLPH EICHHORN, D. V. 5S. Senior Bacteriologist, Pathological Division, United States Bureau of Animal Industry With 29 Illustrations and 5 Colored Plates CHICAGO, U.S. A. ALEXANDER EGER PUBLISHER 1914 COPYRIGHTED AT WASHINGTON, D. C. BY ALEXANDER EGER 1914 SEP -5 1914 COMPOSITION, ELECTROTYPING, PRINTING AND BINDING BY THE W. B. CONKEY COMPANY HAMMOND, INDIANA ©cl.A379406 ae " 41a) Table of Contents PAGE TPGNACIGROIRIS IDIRBENOD Soo scood so dnogsusocounseaeas aoc ou DMUodDUGoD GOD eG vil capih@ipegy ISREAC®, achacoedneoucso sound udu aodsudobo. cu OG OGOUdD OnE OD OOD OUG ase CHAPTER I. Anatomy, Pathology and Histology of the Mammary Gilenelesoccaconosu0ds il CHAPTER II. Physiology of Lactation and Characteristics of Milk in General...........- 16 CHAPTER III. Microscopy of Milk in General.......---.-..+- esse cence etree ete ee cree 24 CHAPTER IV. Composition of Milk and Its Biological, Chemical and Physical Characteristics 32 -CHAPTER V. Procurement of Cow’s Milk PE enh a Aa nearer) ees AOU gt de ary Sere ry tc 58 CHAPTER VI. Internal Influences on the Character of Milk.........-...--. esse cece eee 62 CHAPTER VII. External Influences which Act Upon Milk.........-.- see cece eee ee ee eeee 132 CHAPTER VIII. Bacteria in Market Milk; Their Origin and Action..............++++---- 152 CHAPTER IX. SN Thil licen (G co vattarei mesa eee = aes estas, ey a com ae td ey vedlaue alte velayie iret tara aW'elelr=s @Unehey eartateia a 203 CHAPTER X. IMEI Tin cen 56 sal eoocnoseds cdou bobo woe none UObooUCo CRUE OG nOOOut Pala CHAPTER XI. Fundamental Principles of Legislative Milk Control.............+++.+++-- 233 c Translator’s Preface HE importance of food hygiene in the protection and preser- vation of public health is now generally recognized. Milk constitutes one of the most important foods for the human race, and since its composition and wholesomeness are entirely dependent upon its proper handling, the necessity for a strict supervision and control is obvious. The problem of milk hygiene is very complex and must embody all phases of milk control from the time the milk is produced until it reaches the consumer. In all stages it may be subjected to wilful adulteration and to contamination with injurious and ob- noxious substances. Furthermore, the danger threatens this most valuable food not only from outside sourees but also from internal influences, as the milk may leave the animal in the condition of a dangerous product, a carrier of pathogenic microbes. Various kinds of infection of the udder are frequently important factors in the contamination of milk, which would render it dangerous to the consumers. Thus in recent years numerous outbreaks of in- fectious sore throats have been caused by such conditions. It is therefore apparent that in the proper control of the milk supply it is necessary to be familiar with all conditions which may be re- sponsible for an injurious or unwholesome product. The subject is one in which every sanitarian should be thoroughly qualified. Although there are numerous splendid publications available on this subject, they are either too voluminous to be used as text- books or they fail to contain the more recent very important devel- opments made in this branch of public hygiene. The excellent German publication of Dr. Ernst entitled ‘‘Milk Hygiene’’ meets the requirement of a concise, up-to-date work on that subject, and it is with pleasure that in response to requests from various sources we have accepted the preparation of an English edition of this publication. We did not lose sight of the fact that it should meet with the conditions prevailing in this country and accordingly we Vil Vili Translator’s Preface, have included much valuable information from the reports of the various Milk Commissions, and other sources. For this reason Chapter X dealing with German laws and regulations has been replaced by Chapter XI which deals solely with the conditions and standards existing in this country. We eannot refrain from expressing our sincere thanks to Dr. H. J. Washburn for his most valued suggestions and assistance in proofreading the manuscript; also to the publisher, Mr. Alexander Eger, for his interest and courtesy during the preparation of this volume. JOHN R. MOHLER, ADOLPH EICHHORN. Washington, D. C., July 1, 1914. Author’s Preface HE increased importance of milk as human food demands . more and more the application of modern accomplishments and experiences achieved by science and practice, in order to elevate the milk industry to the desired high standard. The principal stress must be laid upon production, which con- stitutes a special field of the milk industry, and which is most generally in, need of elevation and improvement. The product will be without reproach only when the conditions of production correspond to the value of this food. In the field of production, veterinarians are the proper ex- perts who must stand by the side of the producers and give them the necessary advice and instruction. Only by the active and ex- pert aid of veterinarians can it be hoped to improve the good-will of the producers; provided, at the same time, other points of milk hygiene which possess bad features—in spite of the active progress of milk control and sanitary methods which have been noted for many decades—also receive proper attention. In order to be able to offer expert advice a thorough knowl- edge.of milk, its formation, procurement and characteristics, is necessary; likewise, a knowledge of conditions which have an in- fluence upon milk while still in the animal body, and the factors which change this food after its procurement. These points have received the principal consideration in the following chapters. In the plan which I have followed, those questions which treat of the judgment of milk as human food in relation to its chemical contents, were given less prominence. Certain points of this sub- ject have been mentioned only to an extent that was considered advisable for the general comprehension of the subject. More specific questions, as for instance, the preparation of certain milk mixtures for the feeding of infants, the advantages and disadvan- tages of feeding cows’ milk to infants, the action of a milk diet in the treatment of adults, ete., are subjects for the physician. A 1X x Author’s Preface. special chapter on the preparation of infants’ milk, or certified milk, has been omitted, since the sanitarian can not make any distinction in his judgment of milk as food, but must remember that milk which is consumed by children of the masses should also come up to the requirements established for any food product from a hygienic standpoint. The chemical and physical properties of milk are only dis- cussed to an extent deemed necessary to instruct the veterinary experts in court cases in judging physiological, pathological and external influences. Since the chemical examination of milk should be placed in the hands of the food chemist, I have eliminated the analytical examination of milk and the examination for preserva- tives. For this information I would recommend the numerous publications which have appeared during recent times, as for in- stance, the works of Grimmer and Sommerfeld, Teichert, Utz and Barthel. Only those methods have been deseribed which may be undertaken by the veterinarian and which are sufficient for a thorough preliminary test of milk for adulterations. The illustrations are taken partly from the known works of my previous teacher, Professor Dr. med. Th. Kitt (Pathological Anatomy) and from Friedberger and Frohner’s Methods of Clini- eal Examination; some were drawn by myself. The illustrations of apparatuses have been avoided, as they appear in all commercial catalogues. In dividing the subject into individual chapters repetitions, of course, could not be avoided. With the preparation of this small work I desire to show to my colleagues the road which they must follow in order to cooper- ate from a milk inspection standpoint in accordance with the call made upon their profession. A difficult point of milk hygiene lies in the changing conditions of production and not in the control of milk consumption or in the supervision of milk transportation. W. ERNST. Munich, January, 1913. Cuaprer I. ANATOMY, PATHOLOGY AND HISTOLOGY OF THE MAMMARY GLAND. Development and Gross Anatomical Structure. In the lowest form of mammalian life a group of glandular ducts becomes differentiated from the glands of the skin in the median abdominal region. These ducts exude their lacteal secre- tions upon tufts of hair of the mammary region, from which it is either licked or sucked by the young (duckhill, Ornithorhynehus paradoxus). One of the land duckbills, the spiny anteater (Echidna hys- trix), has lacteal ducts opening within an abdominal pouch formed by a fold of skin of the mammary region in the shape of a pocket, in which the young are protected and nourished during their development. This abdominal pouch is not identical with the tegumentary wall from which is developed the teats of higher mammals, but it may be taken as the point of origin of the different forms of teats. In higher marsupial animals the glandular ducts are united into a complex gland with teats which constitute the orifices of the confluent lacteal ducts. In other still higher species the most varied kinds of gland structures are observed with various forms of teat development. Among the higher mammalian forms the evolution of these anatomical structures may be followed during embryonic life. On both sides of the body, between the anterior limb-bud and the inguinal fold, the milk-ridge develops from a linear thickening of the ectoblast in the form of a ledge- like elevation of the epidermis. Along this milk-ridge a series of at first spindle-shaped, then round enlargements appear, which are separated by absorption of the intervening portions of the ridge. These enlargements consist of masses of epithelial cells, which correspond to the anlage, primordium or point of origin of the true mammary gland of the lowest mammalia. This anlage sinks into the underlying mesoblastie tissue and hecomes surrounded by a proliferating integument, which forms an investment for the growing epithelial mass. From this mammary envelope which becomes more or less flat- tended the fibrous and muscular tissue of the areola and teat are derived. At its base, solid epithelial sprouts grow out from the sides of the conical epidermal plug, later be- coming the lactiferous ducts, while the elub-shaped thickened extremities in the further course of their development, form the milk sinus. Subsequently, the central part of the ectoblastic ingrowth undergoes degeneration and what at first was an elevation, now he- 1 9) Anatomy, Pathology and Histology of the Mammary Gland. a Ve) 4 a) Ms comes a depression. From the middle of this depressed area there appears an elevation that later becomes the teat. In cattle a single excretory canal enters from the bottom of the mammary envelope (point of the teat), into the tissue (the milk duct), the end of which, the milk cistern, breaks up into the secondary lactiferous ducts. The lower opening of the teat con- tains unstriped muscle fibres which act as a sphincter to prevent the escape of milk. (Meckel, Kolliker, Langer, Bonnet, Profé, Schwalbe, Huss, Gegenbauer, Klaatsch.) According to the number of the glandular organs there are distinguished the oligomasts and the polymasts. Cows are nor- mally tetramasts, and usually possess four distinctly separated glandular masses, commonly termed the quarters, from each of which protrudes a long teat. The four quarters are united to- gether in pairs and are arranged symmetrically. Between their bases and the yellow abdominal fascia they have a rich layer of fat. The udder is attached along the linea alba to the yellow abdominal fascia, and to the tendons of the abdominal muscles, by two layers of elastic tissue, the suspensory liga- ment (ligamentum suspensorium mammarum) which penetrates the udder between the two halves. Although the quarters situated on one side show no visible anatomical separation, injection tests with colored gelatin, and ob- servations in cases of inflammation of the udder in natural and artificial infections have proven that the secretory canal systems of the anterior and posterior quarters are separated in the same way as those of the opposite quarters. These canal systems collect into excretory ducts and terminal tubules and finally empty into the milk cistern, which in its upper part is greatly dilated and in its lower part is more constricted. Each quarter possesses a teat (6 to 10 em. in length) from the milk sinus of which, the duct of the teat (ductus lactifera) of about 8 mm. in length, passes to the outside. The entire udder is covered by fine, slightly hairy skin, which extends posteriorly and supe- riorly into the escuteheon or so-called milk mirror. The size of the udder varies in the different breeds and indi- viduals. In the sheep and the goat there are two milk glands, each possessing a teat which stands out in a divergent direction from the one opposite. Each teat has one excretory duet. While the teats of the sheep are finely haired, those of the goat are hairless. The blood vessels of the udder are derived from the branches of the external pudic artery and anastomose with the various venous branches, through which the blood flows posteriorly through the perineal vein into the internal pudie vein and finally into the obturator vein. The greatest part of the venous blood flows laterally into the external pudic vein and anteriorly into the subeutaneous abdominal vein, which forms the immediate continu- ation of the external pudic vein and which is known as the milk Pathological Anatomy of the Udder. 3 vein. It runs bilaterally of the median line, penetrates posteriorly and laterally to the xiphoid cartilage of the breast bone into the deeper parts and then empties into the internal! thoracic vein. The lymph vessels which are very numerous enter two large lymph glands which lie bilaterally in a depression at the posterio- superior portion of the udder and are known as the supramam- mary lymph glands. The lymph passes thence to the lumbar glands and into the thoracic duct. The nerves originate from the lumbar plexus. The udder is supplied by the internal branch of the ilio-hypogastric nerve, the external branch of the lumbo-inguinal nerve, and the external spermatic nerve. In the goat the external spermatic nerve divides in the abdominal cavity into three branches, of which the median and the caudal branches pass through the inguinal ring to the udder. The cephalic branch passes to the abdominal muscles. The caudal branch (inferior) is purely a vascular branch. The median branch passes to the udder, and ramifies to the milk ducts and the teats. Pathological Anatomy of the Udder. Of the pathological processes which are of importance from a practical standpoint, the inflammations and changes which have more or less influence on the quality of the milk are of special in- terest. The other anomalies will be mentioned only briefly. Not infrequently there may be present in cows supernumerary teats, or supernumerary milk glands, which may be considered as a reversion to early stages in the evolution of cattle. Usually two rudimentary formations occur which are generally situated behind the postericr normal glands and normal teats. These may at times yield milk (Burkart, Dauberton). These accessory glands may also occur between the normal teats. In several instances as many as four supernumerary teats were observed. If the udder is abnormally small in its development or is en- tirely absent, it constitutes hypoplasia or aplasia of the udder. According to Bosetti the absence of the mammary gland was ob- served in a cow two and a half years old. Although there were four small teats on the skin, no milk was secreted even after the birth of a healthy calf. The milk veins were well developed on both sides. The opposite condition, hypertrophy of the udder, with or without secretion, is most conspicuous in male animals. Pusch ob- served a buck which produced 70 gm. of colostrum-like milk daily, and which possessed nipples 7 to 9 em. in length. Gurlt has re- ported that the udder of a steer was as strongly developed as in a cow, and produced daily 114 liters of secretion. It is known that newly born kids and suckling colts occasion- ally secrete milk for several days (Gurlt, Martin, Hess, Ibel). Schmidt, of Dresden, reported a giant udder with an entirely 4. Anatomy, Pathology and Histology of the Mammary Gland. normal milk secretion, (16 liters). A funetional hyperemia in the beginning of the lactation period increased the four quarters uniformly to such an extent that a day after parturition the udder touched the ground with its central surfaces. Before and after parturition an abnormal amount of hy- peremia occurs physiologically in the udder (hyperemia conges- tiva). In inflammations the same condition may be present, the capillaries are abnormally dilated, and greatly distended with blood. This condition may result in the exuding of fluid and the solid constituents of blood. These are known as capillary hem- orrhages. In larger extensions of these hemorrhages they are spoken of as suggilations, and when the blood is contained in a sac-like cavity or swelling it is known as hematoma uberis. If in the congestive hyperemia the fluid constituents of the blood pass into the tissue of the udder, it results in edema of the udder. The same condition may develop as a result of hydremia, as for instance after changing from dry to sloppy foods (Bang), or as a result of multiple emboli of the blood vessels, or from a varicose condition of the veins of the udder. Edema of the udder manifests itself as a soft or tense swelling of the tissue, which retains the impression of the finger. While the teats usually remain normal on account of their slight but dense connective tissue, quantities of fluid collect in the front of the udder and between its glandular substance and the skin. The edema frequently extends posteriorly to the udder and up to the vulva. In- ecauone of wounds with the bacillus of malignant edema may result in edema of the To those engaged in milk hygiene the most important of all pathological conditions of the udder are the inflammations which result from a reaction of the glandular tissue to any inflam- matory irritant. In most instances the inflammations of the udder are produced by microbian infections of various kinds, particularly by poly-bacterial infections. The bacteria penetrate the udder either by way of the blood cireulation or from the outside through the orifices of the milk ducts. In such cases it is spoken of as a hematogenic or galactogenic mode of infection. If the infection results from a mixture of bacteria, and is not caused by one kind alone, the affection is a mixed infection. The infection may result from traumatic conditions when injuries extending into the paren- chyma of the glands make the infection possible, or from galactif- erous-traumatic causes when the infectious material enters the milk cisterns upon milking tubes or straws. The infection may take place also through simple contact of the orifice of the teat with the infectious material. Thus the different forms of mastitis, the peracute, acute or chronic inflammations of the udder may arise, depending upon the character of the infectious material and upon special accessory conditions. The possibility of galactiferous infection was first experimentally proven by Frank. The character and the varieties of inflammations of the udder were further established by the work of Kitt, Nocard and Mollereau, Lucet, Bang, Hess and Borgeaud, Guillebeau, Zschokke, Sven Wall, and others. Pathological Anatomy of the Udder. 5 The principal producers of mastitis are the colon-paratyphoid group, staphylococci, streptococci, Bacillus pyogenes bovis, Bacillus tuberculosis, and the actinomyces. Colon infection and severe mixed infections usually result from galactiferous contact, or after the introduction of milking tubes, straws, quills, cat-guts, and hairpins. Highly acute, inflam- matory conditions develop in the affected quarters, whether af- fected throughout or only partially with parenchymatous mas- titis. Hot, painful swellings of the quarters, with collateral edema Fig. 1. Acute inflammation of the right forequarter with collateral edema. (After Witt.) of the surrounding tissues, are the associating symptoms of this form of inflammation, which either results in recovery with atrophy of the affected parts of the udder, or with regeneration of the epithelia destroyed by the disease or on the other hand the di- sease becomes chronic and may even terminate with complete gan- grenous and ichorous destruction of the affected part of the udder. In the infectious forms of mastitis the supramammary lymph glands may swell to fist-sized nodes. If the process becomes chronic a suppurative softening of the affected parts of the tissue, or a suppurative demarcation of ne- erotic parts of the tissue results. These conditions are designated as suppurative and purulent mastitis respectively. 6 Anatomy, Pathology and Histology of the Mammary Gland. The acute forms of mastitis interest those engaged in milk hygiene but little, since noticeable changes in the milk quickly fol- low the commencement of the inflammation, and the animals soon stop their secretion. On the other hand the hidden forms of inflam- mation are of the greatest importance because the milk is fre- quently almost unchanged, and does not always indicate its ined- ible condition. Such conditions of the udder may vary from a simple catarrh to a purulent inflammation. The manifestations of these forms of inflammation vary to a great extent, and the symptoms may be only slightly pronounced, so that a single clin- Fig. 2. Fibrinous form of parenchymatous mastitis; separation of quarters plainly visible. (After Kitt.) ical examination may cause a suspicion, but a positive diagnosis eannot always be established. Literature shows that slightly marked swelling of the affected quarters, increased local temperature, nodular formation of the parenchyma, and induration of the glandular tissue, may appear in the most varied forms, sometimes with and sometimes without general symptoms. At the beginning it may be localized around the base of the teats, but the hardening of the glands then pro- gresses forward, upward and backward (Sven Wall). The examination of the milk ducts should not be neglected. The mucous membrane of the cistern may have become inflamed, Pathological Anatomy of the Udder. ui resulting in ulcerations, scar formations or polypoid prolifera- tions, which are difficult to recognize. Sometimes such changes of the teats are characterized by cicatricial contractions (strictures). The udder, which usually becomes affected in the individual quar- ters, may remain either normally soft, or may become somewhat harder in consistence. The yellowish-red, normal color of the cross-section disappears, and changes into a grayish-orange or brownish-gray tinge. The parts which are of a harder and tougher consistence show an increase of connective tissue; the interstitial connective tissue changes into a bluish-white thickened network. Fig. 3. Purulent mastitis showing necrotic foci. (After Kitt.) The edema of the skin which develops at the beginning of the inflammation results sometimes in extensive sclerosis, even the parenchyma of the glands being sometimes dislodged by the pro- liferating connective tissue causing the quarter to atrophy and harden. Tuberculosis although almost invariably resulting from a hematogenous infection, appears either in the form of a single focus (tuberculosis uberis cireumscripta), or it may be dissem1- nated over the entire parenchyma (tuberculosis embolica dissem- inata), or the tissue may be diffusely affected, becoming infiltrated throughout almost its entire extent (tuberculosis diffusa). These 8 Anatomy, Pathology and Histology of the Mammary Gland. forms of the disease may be present in combination in the same udder. During the tuberculous invasion nodular indurations of the tissue develop, which hypertrophy and become tense, hard and knotty. The lymph glands usually manifest hard, painless, thick- ening, and nodular formations. Caverns may also develop in tu- bereulosis of the udder. Actinomycosis which commonly develops from the penetration of actinomycotie barley beards, or particles of straw into the tissue, or more rarely by embolic infection, may also be produced experimentally by the injection of solutions containing actin- omyces through the milk ducts. Actinomycosis of the udder has been observed in cows by Peterson, Rasmussen, Bang, Harms, and Jensen. Nodular formations, connective tissue proliferations and softening of the tissues, localized or in larger areas, are also ob- served in this disease. Botryomyecosis and glanders enter into consideration only so far as the udders of mares are concerned. For completeness, various growths may also be mentioned as anomalies of the udder, such as fibroma, adenoma, adenofibroma, adenocarcinoma, chondrofibroma, chon- droma, lipoma, sarcoma, angioma, ete., which are dependent on the tissue elements and the character of the tissues of which they are composed. Cystic formations have also been observed. é Not infrequently the connective tissue and the subeutis of the udder of cows may show bone formations in the form of bony hooks and plates, (ossificatio plana or racemosa). Parasites have also been found in the udders of cows, namely echinococci (Behmert and Steuding). For further information see Kitt, Pathol. Anatomy, 1910, Vol. 1, page 280. The author once concluded that a goat affected with adenoma papilliferum uberis was troubled with mastitis, basing this decision upon an examination of the milk, although the secretion contained no specific inflammatory agents. The continually increasing quantity of milk was remarkable. Postmortem and histological examination finally revealed the adenoma in the udder. Structure of the Tissue The external skin of the teats possesses neither hair nor sebaceous or sweat glands, and continues as cutaneous mucous membrane into the milk ducts, which it lines up to the cistern. The mucous membrane has no glands, possesses fine folds running lengthwise, and is covered by pavement epithelium which is supported upon a well developed papillary base, and is firm and horny next to the lumen. The papille are extraordinarily long; they apparently branch near the base, and slant towards the orifice of the teats. This cutaneous mucous membrane of the milk ducts continues without demareation, with the mucous mem- brane of the milk cistern, which is covered by several layers of eylindrical epithelium, and possesses accessory glands which are lodged in the connective tissue. The wall of the teats contains bundles of involuntary muscles running lengthwise and crosswise, forming a strong and elastic encasement around the canal of the teats. The supporting structure is penetrated by numerous blood Structure of the Tissue. 9 vessels and lymph vessels. Numerous and strong elastic fibres strengthen the dense fibrillar connective tissue of the teats. In order to describe the finer structure of the parenchyma of the udder it is necessary at first to touch on the further develop- ment of the organ from birth until the moment of the appearance of the secretion. | (a) Normal Appearance. The milk gland is an organ which performs increased fune- tions only at certain times. It does not secrete during the entire Vertical section through the lewer end of the teat canal which is closed by a horny plug (a). life but only when the newly born offspring is to be nourished by the milk. The udder of a virgin animal does not correspond even in its finer structure, with the appearance of a fully secreting udder, and this again varies in its finer structure from a gland which is at the beginning or at the end of the lactation period; even this is not all, since the microscopical appearance changes in ac- cordance with the condition of activity, where a lobule or only a part of the lobule may be found on examination, depending whether the cell-complex is just forming the secretion or has al- ready discharged its secreted product. The gland of a newly born calf shows but relatively few cell tubes and cell buds, imbedded in connective tissue rich in fat and branching in all directions. These prac- tically form the basis of the glandular duets and are without alveoli. The end of the tubes is frequently somewhat dilated, or thickened in the form of a club. 10 Anatomy, Pathology and Histology of the Mammary Gland. With puberty the alveoli appear in the cow surrounded by strong connective tissue. In older virgin individuals they sometimes show a slight amount of secretion. A considerable increase of the glandular tubes appears only after the first conception. The tubes become more dilated and branch more and more, forming alveoli, from which other ducts bud out. Although indications of secretions in the cells may not yet be visible, the cavities contain a homogenous or fine granular mass of cells or cell fragments. The gland prepares for the secretion, growing at the expense of the atrophying or expanding connective tissue, until ready to commence its secretion. Fig. 5. Net * 7 . - . " <. ss * & K ah 8 rs 2 A &. PLA 2 Superior portion of the teat canal (a) with a reflection of the cutaneous mucous membrane of the cistern (b). The cell lining of the larger glandular ducts is of double layers, as in the cistern, while that of the smaller ducts and al- veoli is composed of only a single layer. The epithelium of the latter appears cubical or flat, while the upper layer of the former is cylindrical; in the deep layer the cells are more cubical and rounded, partly wedged in between the bases of the superficial cylindrical cells. The borders of the cells are sharp and the proto- plasma is clear. The nuclei of the epithelia frequently show mi- tosis, that is, division and multiplying forms. The cells rest on the so-called basket cells and the membrana propria. The basket cells Structure of the Tissue. Hab should be considered, according to the investigations of Benda and Bertkau, as involuntary muscle cells because of their appearance and their staining qualities. They probably play a part in the emptying of the glandular ducts and the milk secretion. Blood capillaries, lymph vessels and nerves run in the inter-and intra-lobular con- nective tissue, which is strengthened by elastic fibres, and contains involuntary muscle cells. Therefore, the same tissue elements are represented as in the teats, with the ex- ception of the many-layered pavement epithelium. Structure of the mammary gland in secretion, Hematoxylin. 1 X 800. (a) Secreting glandular alveoli. (b) Alveoli with dormant cells. At the end of pregnancy the picture again changes consid- erably. The protoplasm of the previously clear epithelial cells of the secretory system becomes cloudy, the nuclei larger, their chro- matin collects in flakes on the periphery of the nuclei, the borders of the cell become indistinct, the cells become swollen, the nucleus lies in the center, and the indications of the division by indirect fission of the nucleus appear relatively in groups. Some epithe- fal cells show two nuclei at this stage; towards the alveoli fat globules appear. Leucocytes with which a few eosinophiles are mixed, collect beneath the epithelial cells and penetrating the _ 12 Anatomy, Pathology and Histology of the Mammary Gland. epithelial layer, separate themselves from the epithelial cells and enter the alveoli, which at this stage contain fatty secretions, leucocytes and epithelial cells in all stages of degeneration. With these manifestations the gland cell commences its function. The desquamation of epithelial cells and the cell de- generation disappear; the cellular infiltration of the connective tissue recedes until it is very slight between the now greatly di- waete 08 + BBO) Oe ~* < a! r oat OB GE Steen *e,* © Chronic mastitis of cow. 1 800. (a) Thickened interstitial tissue. (b) Alveoli. (c¢) Blood vessels. (1) Epithelial desquamation. (2) Colostral bodies. (3) Cellular infiltration. (4) Fatty degeneration and necrosis. (5) Milk concrement. lated and distended glandular ducts. The cells are finely granular on the basilar border, and at times show striation, that is, fine streaks running in parallel directions (bioplasts according to Altmann). The nucleus is large and vesicular in shape; the upper part of the cell is granulated and shows large and small fat globules. This granulation and streaking may be seen, according to Steinhaus and Duklert, at each act of secretion. The fine fat globules collect Structure of the Tissue. iffy into larger ones, which are only separated from the lumen by fine protoplasm, or having been expelled have already entered the al- veoli. With the collection of the secretion these dilate, the cell becomes flattened during the expulsion of its products, and the part lying towards the lumen appears indistinctly bordered as if shredded after the expulsion of the fat. They soon become smooth again, and by the pressure of the alveolar contents and the dilation : ‘ %, ee age h Af eee) se Ms z = Chronic mastitis of cow. 1X 90. (a) Healthy portion. (b) Glandular portion with chronic mastitis. of the alveoli, the cells sink and become so flat that the nuclei not infrequently appear bulged out towards the lumen. After the expulsion of the secretion the formation of additional secretion again commences in the cell, the protoplasm again becomes cloudy and granular, and so on, a continuous change of the form of the cell taking place. ; During the entire lactation period, but more so in the later stages, manifestations of atrophy of the gland appear, at first 14 Anatomy, Pathology and Histology of the Mammary Gland. commencing at the base of the gland, and finally during the end of lactation in the entire udder. Epithelial cells are thrown off, the alveoli become fewer, smaller, and irregularly distended, the con- nective tissue increases, and cellular infiltration starts under and between the epithelial layers. The epithelium contains no fat globules, it is sharply bordered towards the alveoli and the pro- toplasm becomes pale. Finally the last remains of the secretions Acute streptococcic mastitis of sheep. 1 * 1000. (a-1) Blood capillaries. 2. Thrombosis by disseminated streptococci. (b) Glandular alveoli, with clumps of streptococci. (c) Migration of leucocytes into the infected alveoli. disappear, the plasma cells and leucocytes taking care of the resorption. At the end of this process the gland is at rest, and the cow is dry. Of course these processes are not always so schematically uni- form as they have been described. During the entire lactation period, colostrum-forming, and retrogressing lobules may be ob- —— Structure of the Tissue. 15 served; likewise certain parts of the udder may remain in secre- tion during retrogression until storing of the secretion, leucocytic resorption activity and connective tissue proliferation cause them to cease their activity. (b) . Pathological Appearance. Any kind of irritation of the gland, such as stasis of the milk, especially in chronic catarrhs and inflammations, may result in the most varied kind of pathological conditions, either in mixed form or individually. The manifestations vary, depending upon whether degeneration and destruction of the tissue, or reparation and recovery gain the predominance. Sometimes desquamation of epithelium, with or without fatty degeneration, occurs together with cellular infiltration of the in- terstitial connective tissue and capillary engorgement as the only indications of inflammation; or, on the other hand, the changes in the interstitial parts may be very pronounced, while the changes of the parenchyma may be less prominent. The inter- and intra- lobular connective tissue extends forming thick indurations, from which the separated epithelium is compressed to small necrotic nests. In other stages of inflammation the cellular infiltration of the tissue predominates. The alveoli and the milk ducts are plugged up thickly with leucocytes, and dilated with the pus. In highly acute inflammations the rapid breaking down of cells, de- struction of epithelium, serous and cellular infiltration of the tissues even to their dissolution, are the principal manifestations. The ducts and the alveoli are inundated with serous, bloody co- agulated masses. In stasis of the milk, and in all inflammatory manifestations, especially of the acute form, the alveoli contain hyalin and con- erement arranged in layers, in addition to inflammatory cells and broken down cellular products. CHapter II. PHYSIOLOGY OF LACTATION AND CHARACTERISTICS OF MILK IN GENERAL. As already mentioned the udder secretes only in certain lactation periods between births. The lactation lasts under nat- ural conditions in healthy animals as long as the young needs the glandular secretion for its nourishment, and stimulates the lactation by the irritation of the intermittent suckling. Shortly before parturition, or at the time of parturition, the glandular tissue terminates its increase in development, and the milk secre- tion starts and becomes actively established. The causes of the increased cell production during pregnancy, and for the secretion after this time, are variously explained. Nervous irritation from the genitals to the milk glands may by means of reflex action stimulate the glands into activity. That such reflexes on the genitals may originate from the milk gland is proven (Pfaundler). Reflex actions in the opposite way, however, have not been proved (Halbau). It has been impossible either experimentally (extirpation of the lumbar cord) or by accident (fracture of the spine), to pro- duce a complete ‘‘nervous isolation,’’ since as emphasized by Pfaundler, there are still remaining the nervous connections through the vasomotors. However, the re-section of nerves, oper- ations on the spinal cord, transplantation experiments, ete., by Eckhardt, Rohrig, Sinety, Busch, Mirnow, Pfister, Ribbert, Golts and Ewald would suggest that besides the nervous influences, which undoubtedly exist, there must be some other agent which stimulates continuous growth during pregnancy, terminates the same with the end of parturition, and inaugurates the secretion. Hematogenic influences may be readily accepted, as they may be led to exert their action either by the quantity or by the quality of the blood. After parturition the body and the milk gland have at their command great quantities of blood which was previously utilized by the gravid uterus. The plethora which appears at this time may be held responsible for the inauguration of the secretion, after the udder has been rendered ready for action by the increase 16 Milk Secretion. aye of its growth through nervous influences. On the other hand it has been observed that in other conditions, in which there exist also a diversion of great quantities of blood from the genital parts for the supply of other organs, as for instance after operation on very large tumors in the region of the genital organs, no secre- tion appears even when the udder is prepared for the secretion. As a matter of fact the secretion may commence before birth, and even in early abortions, or if the fetus dies. At times when the uterus is only so slightly distended that the quantity of blood set free after abortion is hardly sufficient for an effective hypere- mia of the milk gland, the secretion of milk may result (Sinety, Kreidl, Mandl). Therefore the explanation that the quantitative influences of the blood may give rise to a stimulation of the milk secretion (Freund), can scarcely be accepted. Consequently the qualitative changes of the blood must be considered as more prob- able factors. Authors have diversified opinions upon this question. While some accept the view that substances are eliminated from the impregnated organs, or by the fetus itself into the blood of the mother by internal secretions, and that these act as stimu- lants on the milk glands, others believe that the factors causing lactation lie in the assimilation of certain nutritive substances. The supporters of the theories of ‘‘stimulation substances’’ (Sinety, Halban, Starling) take the stand that stimulating sub- stances which cannot be utilized for the cellular growth and cellu- lar activity, contrary to the nutritive substances, cause the devel- opment of the gland during pregnancy, and at the same time pre- vent it from secreting (stimulines, hormones [I stimulate], sub- stances of pregnancy). Development of the gland and prevention of secretion inay, of course, be the action of one and the same sub- stance (Hildebrand, Starling), or its development, as long as the growth continues, may retard secretion. With birth the stimula- tion of growth and development ceases, and secretion commences. Contrary to this, the theories of nutritive substances empha- size the fact that the glands at times may start the specific activity without the presence of certain stimulines, probably through nutri- tive substances which are present in the blood at various times. Rauber attempts to explain the activity of the gland after birth by declaring that after the expulsion of the fetus a nutritive material becomes available, which has served prior to birth for the preparation of nutriment for the offspring. While the ex- planation of the author that the lymph cells play the most impor- tant part in this can no longer be considered, still it furnishes the basis for all new theories relating to the action of nutritive substances. These views were strengthened in 1908 by Schein by the state- ment that during pregnancy the mother animal, in order to meet the requirements of the fetus and of the impregnated organs, en- 18 Physiology of Lactation and Characteristics of Milk in General. riches her blood with the so-ealled ‘‘milk producing substaneces.”’ Pfaundler recommends the designation ‘‘offspring nutritive pro- ducing substaneces.’’ Since during pregnaney the continuously developing placenta utilizes and consumes these substances for use in the nourishment of the young, there remain for the milk gland only shg¢ht remnants, just sufficient to result in the necessary stimu- lation for the cellular increase in the gland. After parturition when the activity of the placenta is completed, the milk Bena takes up the released nutritive substances for its own use (specific af- finity of the substances to the cells of the milk gland), and is stimulated to secretion by the quantity of the disposable material. Sechein’s milk producing substances in the blood constitute the initial material for the formation of specific components of the milk, milk sugar, casein and milk fat. The material acquired by the mother, through placental con- tact with the fetus, while aiding in the development of the latter is also of benefit to the activity. of the milk gland, whose product adapts itself exactly to the requirements of the young, as far as it concerns the material which the young uses for the growth of its body. If conception again takes place the developing placenta of the new fetus enters into competition with the lactating gland, and draws from it milk producing substances for its own use, whereby the secretion of the milk gland becomes reduced or ended. Influences exerted on the milk gland by oestrum or puberty, and also the impulse of pregnancy, have not yet been sufficiently explained through this theory. Pfaundler enlarges upon and ex- plains these phenomena by stating that the withdrawal of certain nutritive substances, through the germinal gland, embryo and ovum, and not the appearance of milk producing substances alone, periodically disturb the equilibrum of physiologically acting sub- stances in the blood, and thereby the antagonizers of those sub- stances (the stimolines, harmones of other authors), are enabled to find specific receptors (affinities) in other organs of the genital apparatus. After birth, continuing intermittent stimulation may retain or increase the lactation of the milk glands for a longer or shorter time. Stasis of the milk diminishes and retards the secretion. Rievel opposes Schein’s view, since in his opinion it does not explain how udders of animals in which neither pregnancy nor birth has preceded, could start secretion (lactation of milk glands of the newly born or virgins, occasionally even of male animals). According to the author’s view these facts would not oppose the theory of nutritive substances. Schein, himself, aims to bring these observations into harmony with his views, and asserts that the newly born may give a secretion from their milk glands, when towards the end of pregnancy the activity of the placenta is dis- turbed, and as a result small quantities of the ‘‘milk producing Milk Secretion. 19 substances’’ enter without changing directly into the blood of the fetus, and thence into its milk gland. Sufficient stimulation for the secretion and formation of the so-called ‘‘witches milk’’ re- sults. Schein explains the formation of milk in virgin mamme, or in milk glands of individuals which have passed their climacterie, by the fact that through the stimulation produced by sucking, the secretory cells are awakened from their dormant state and then utilize the milk producing substances in the blood for the perform- ance of their functions. Finally (1910) he concludes that the oc- currence of milk secretions in nullipera and in women who have passed the climacteric, which differs from the gradually inaugu- rated normal lactation as a result of pregnancy, and also the ob- served secretion by the breasts of newly born and of male indi- viduals, represents a continuous secretion analogous to the normal secreting process in other glands, in which the product is as a rule, however, re-absorbed by the glandular elements. In pregnancy and at birth the secretion is increased to the greatest extent, but other stimulants may under certain conditions stimulate the activity of the gland. Duval’s more recent observations contain data relative to the occurrence of milk secretion by women outside of their normal lactation periods. It is not uncommon to observe secretions in virgin animals especially when young animals which are present stimulate the udder intensively by sucking. It should be emphasized however that the udder secretion of virgin animals distinguishes itself in its appearance from the milk of mature milking animals; it repre- sents a secretion which does not even deserve the name of milk. The experiments which were conducted by various authors in support of their lactation theories appear of interest. The experiments of Starling aim to show the presence of bodies in the blood during pregnancy which prevent secretion, in which claim is made that an interruption of pregnancy in rabbits at a time in which alveoli capable of secretion were not yet present, led to a retrogression of the milk gland, while in the later periods of pregnancy secretion was induced. According to Pfaundler’s view the harmone theory could be effectively supported by the fact that an existing secretion may be successfully interrupted or prevented by the introduction of serum of pregnant animals of similar species. The author does not believe that this proof is satisfactory and mentions observations made in a ease in which the secretion ap- peared at birth of twins which were born at long intervals, that is, the pregnancy continued after the first birth, yet the milk secretion eontinued unchecked. Wucherer observed a case in which a sow gave birth to nine, and seventeen days later to six other pigs. At the birth of the second lot the first born pigs were taken from the sow. These continued to thrive, but of the second lot only three remained alive. He emphasizes the opinion that a transitory Ap) Physiology of Lactation and Characteristics of Milk in General. action of blood serum, as used in Pfaundler’s experiment, which corresponds only shghtly in its composition with the normal blood serum, ean never be favorably compared with natural influences in the body. This exception must hold also for the indecisive ex- periments of Starling, who by injections of juices from rabbit em- bryos, but not with injections of preparations from rabbit ovaries, placentas and mucous membrane of the uterus, produced a devel- opment of the glands, and at times a degree of milk secretion. He believes that the true cause of the secretion may be found in the ehemical changes which are produced by the growing embryo and are brought to the glands through the placental circulation. Re ene Pee, 3070.0 to 6308.6 SiWiSSiaeeer tae te ee ae ee ees 2.33 4008.0 to 5326.7 SIMO MTgtsEN ONeM Dewees actas eric Menstinne coheeeatons tons Be Ataf 2.76 IM LOTR NOTEVER Een es Ns aes eee epee eR 2.62 NOUSte mem cys te irc, ele cbacas sence aes 2.58 isrettenbunceriss tives. aes. Sts ewone 2.46 According to Grimmer the number of milk globules fluctuated in 21 tests on three herds of blackish-brown lowland cattle in Pomerania, from 1,330,000 to 3,073,000 per cubic millimeter, having an average diameter of 2.6-3. Tp The milk globules retain their form through their surface tension and are not surrounded by special capsules which could be considered as membranes, as has been thought by former authors. 40 Biological, Chemical and Physical Characteristics of Milk. Although the milk globules cannot be entirely freed from proteids by washing (covering the milk with water and allowing the separation of fat), the demonstration of the remains of proteids cannot be considered as proof of an actual ‘‘haptogen mem- brane’’ which must be broken down during the butter-making process, in order to make possible the flowing together of the milk fat, but it does constitute a proof that rem- nants of proteids, even after the most careful washing of the cream, remain around the fat globules. At least it has never been possible to demonstrate membranes of the fat globules, neither in boiled milk, in which during continuous heating larger fat clumps develop, nor in fat extractions (Soxhlet, Quincke, Morres). Milk sugar is also a specific substance of milk. It is formed in the gland and is found only in its secretion. If sucking is in- terrupted, it may be present in the urine, from which it immedi- ately disappears upon amputation of the lactating gland, or it may not appear at all when the gland is amputated before the appear- ance of lactation (Sinet, Magnus-Levy, Zuntz). After the com- plete removal of the gland in eoats and cows, however, a temporary hyperglycosemia and elycosuria appear. Tf parts ‘of the gland remain, lactosuria results. After the injection of glucose, lactose appears in the urine (Porcher), likewise after the ingestion of large quantities of dex- trose. Since the blood in the mammary vein before parturition and during lactation contains considerably less glucose than the blood of the jugular vein (Kaufman and Lagne), it may be accepted that glucose has been utilized in the gland, and further that glucose is the material from the constituents of which the lac- tose is formed in the gland. Of the various salts milk contains compounds of potassium, calcium, magnesium, iron, traces of manganese, aluminum, phos- phorie acid, hydrochloric acid, carbonie acid, sulphuric acid, citrie acid, fluorine and iodine. Carbonic acid, oxygen and nitrogen have been demonstrated as gases in the milk. Besides these substances, lecithin, cholesterine and coloring matter are present in the milk, besides ferments and substances which are collected as residual substances; these have been pre- viously mentioned. Raudnitz and Grimmer have recently published compiled arti- eles relative to the individual constituents and chemical properties of milk which contain the collected material of many experimental results, and at the same time show how much is still unsettled in regard to the composition of milk and the characteristics of the substances which it contains. Certain physical characteristics of milk correspond to its chemical condition. These adjust themselves according to the pro- portion of the various constituents, and to the conditions attend- ing the mixing of the different component parts. The appearance of the milk is influenced by the suspended easein and the proportion of fat. Skimmed milk, which is almost free from fat constitutes a non-transparent, somewhat bluish fluid, as compared with the whitish yellow color of whole milk. The ad- Specific Gravity of Milk. AL dition of alkalies to milk free of fat renders it transparent. Ham- marsten furnished the proof that a calcium caseinate solution which corresponds to the composition of milk is almost as non-trans- parent as milk. The milk becomes less transparent the smaller the fat globules are. This is most strikingly apparent when the fat globules are broken up to dust-sized bodies (for instance through homogenization). The appearance of fresh milk is also influenced by the coloring matter present in the milk plasma and in the fat. It is known that the skimmed milk of certain cows varies considera- bly in color; at times it is bluish white, sometimes more yellowish green, again transparent, other times of a non-transparent whitish color, and also the fat has a more yellow color during the pasturing of the animals than at the time of stable feeding. The non-transparency as mentioned above is no proof of the presence of fat in the milk; therefore all methods which are destined to establish the quantity of fat or addition of water by the establishment of the whiteness, are of no use, as for instance, Heeren’s pioscope, Feser’s lactoscope, ete. Tf milk is allowed to stand for a time, cream forms on the surface; the fat globules rise and collect usually as a distinct layer of cream above the milk. The rapidity of the separation depends on the temperature, the size of the fat globules, and the density of the milk plasma. The quantity of the cream is not in parallel rela- tion to the quantity of fat; it depends on the size of the fat globules. The separation of cream may be hastened and increased by centrifugalization. During separation while allowing to stand, about 85% of the fat rises to the surface, while by a perfectly operating centrifuge the separation of cream may be accomplished up to 0.01% of its fat. The specific gravity of the milk depends on the solid sub- stances, the relation of the mixture and the condition of the sus- pended, dissolved, and emulsified constituents of the solid sub- stances. Corresponding to the variable composition of cow’s milk it is natural that the specific gravity of the milk should vary. It fluctuates considerably, varying from 1.027 to 1.034 at a temperature of 15 deg. Similar to the impossibility of speaking of milk of normal composition, one cannot speak of milk of normal specific gravity, and even to give average figures would be of very problematical value; but to take such average figures or even smallest values as a basis for the calculation of falsification would be a gross error. Milk from many cows would under ordinary con- ditions have a specific gravity of 1,029 to 1,033. The specific gravity is measured, or is calculated from the values of fat contents and solids, according to formulas, which, depending on the milk from certain breeds, or certain localities, show slight variations. This formula made on the basis of the value of the specific gravity of the milk fat (about 0.95), and the solids or dry substances (1.6001), which is quite constant, is according to Fleischmann: 49 Biological, Chemical and Physical Characteristics of Milk. 1000 ~* 1000-—3775°(d--122'f) In these equations s stands for specific gravity, d for dry substances or solids, and f for fat. The following values may also be calculated from the fat con- tents of the milk and its specific gravity. 1. Total solids: d—1.2 f-++-2.665X 2. The fat-free solids are shown by deducing the percentage of fat from the percentage of the total solids. 3. The specific gravity of the solids sxd 7 sxXad=(100 s=100) 4. Finally the fat contents when the solids and specific grav- ity are known: ) 100 s—100 S , 100 s—100 = S The values obtained from formulas are of course not abso- lutely correct, but represent the results only approximately with the analytical methods of weights, the fat-free dry substance of the milk is not of absolute constant composition, but varies, so that its specific gravity which is based upon the sugars, proteids and salts, varies more or less from the number which has been accepted by Fleischmann as the average value (1.60). The equations hold only for cow’s milk. If milk is freshly drawn, and immediately tested it shows a considerably lower specific gravity (0.0008-0.0015), than after cooling. The milk ‘‘contracts’’ and becomes constant in its specific gravity only after standing for several hours. The cause of this manifestation is not yet entirely clear. Toyonaga aims to explain it by the fixing of previously uncooled and fluid fat globules, which is the most plausible explanation; other authors believe that the contraction is the result of a cessation of the expansion of the casein. The density of the milk varies in accordance with the tempera: ture. The maximum (for water at 4 deg.) lies almost near its freezing point, namely at 0.3 deg. C. The freezing point of milk is somewhat lower, namely —0.54 to —0.57 deg. This is especially influenced by the presence of salt, less by the sugar contents of the individual samples of milk, and it is induced by the relatively constant amount of soluble salts in the salt contents, which is subject to only slight fluctuations in the milk of healthy animals. For the sake of completeness the electrical conductibility of the milk should also be mentioned. This varies according to the re- sistance which is offered by the fluid to the current. It fluctuates f=0.833 d—2.2 Polarization of Milk. 43 within wider borders than the freezing point, and is influenced ac- cording to Zanger by general diseases, through local affections of the udder, by estrum, pregnancy, feeding, etc. The conductivity is diminished by the fat globules; therefore skim milk conducts better than whole milk or cream. The conductivity of the different quar- ters is inversely proportional to the quantity of milk, in milk from different quarters of one cow (Schnorf). The viscosity of milk is a factor which principally depends on the condition and on the quantity of the casein and the fat. Higher temperatures reduce the viscosity, likewise shaking ; quiet standing increases it. The surface tension of milk is lower than that of water (0.053 against 0.075). Of the physical properties the specific gravity of milk and its serum, and the polarization of milk serum, are of special impor- tance for the practical testing of milk (see technique). For practi- cal results, however, the determination of the fat contents is also necessary. As it has been shown the total solids may be determined by the aid of the fat contents and the specific gravity and the fat-free solids may be established by deducting the percentage of fat, these four factors are generally sufficient for the preliminary tests. For more accurate study these preliminary tests are com- pleted by the establishment of the specific gravity of the milk serum, or still better by the refractoscope to determine the chlorids of calcium serum, which renders more rapid work possible. This is a method whose satisfactory use in practice has been proven by the numerous works of Mai and Rothenfusser. Publications relative to the polarization of milk were issued by Valentin in 1879, and later continued by Villiers and Bertault, Braun, Utz, Lam, Radulesku, Ripper, Schnorf and others, on ren- net serum, acetic acid serum and milk serum, which had been pre- pared by voluntary coagulation. The given values of the authors varied in accordance with the method of preparation of the serum; nevertheless it could be estab- lished that comparatively uniform figures were obtained whenever the work was carried out under similar experimental conditions. In 1908 Cornalba showed that contrary to the variance in the amount of colloidal substances dissolved or suspended in milk, the sum of the dissolved constituents of milk is very constant. Whereas in samples of mixed milk the sum of the first substances varied between 5 and 8.585 per cent. the differences for the total dissolved substances were only 6.05 to 6.25 per cent. Milk serum which contains the dissolved substances, offers therefore constant results in the examinations, the same as the examinations which lead to the establishment of the fat-free solids, which still include the casein. Examinations of serum are therefore of the highest practical value for the demonstration 44 Biological, Chemical and Physical Characteristics of Milk. or establishment of the addition of water, provided that the serum is always prepared in the same way. Ackermann, Mai and Roth- enfusser have in their fundamental works, determined the practi- cal importance of the polarization of the proteid-free serum, and have proved that with the polarization of the chloride of caleium serum we possess means which are better adapted than any other to the detection of the adulteration of milk by water. Refrac- tion is the most valuable accessory to the various methods of tests of recent times. Ackermann found in 2,800 samples of normal milk, variations in the scale division of Zeiss’s immersion refractometer, from 38.5 to 40.5. Even slight additions of water reduce the refraction con- siderably; the addition of 5% of water results in a 1.3 lowering of the scale division, while 10% lowers it 2.3. According to Mai and Rothenfusser the original refraction of 39 scale divisions is lowered to a refraction of: 37.9 with about 4% addition of water oe (74 (74 37.7 Dyer : 37.5 4 cc 6% ce ce 74 37.3 ce 66 7% (a4 66 ce 37 wal ce (4 8% ce 6 6 36.9 66 ¢¢ 9% (73 (74 (a4 3 tai 6 66 10% ce ce (74 36.5 oe 6 11% 4 66 66 3 3 ce ce 12% ce 6 (74 36.1 ce 66 13% 4 eo 4 35.9 6c 74 14% cé ce 6 ao co ce 15% ce ce ce 35.5 a (74 16% 6 ce ¢¢ 35.3 (4 C6 17% ¢é ce 6 3 | 66 (74 18% (a4 (74 ¢ 35.0 6 ce 19% eo ce ce 3 8 oe (73 20% ¢ 6é ce 34.0 ¢ 6 20% 66 ce C4 33.3 ce 66 30% oe ce a4 Be 6) a4 (73 30% ce ce ¢ 39 (a4 (74 40% ce 6c (4 30 9 (a4 (3 0% 66 (73 6e In the establishment of the refraction index of the chloride of calcium serum it was also discovered that it is impossible to estab- lish normal values for the chloride of calcium serum, as well as for other constituents of milk. Mai and Rothenfusser also estab- lished the general rule for milk, that only in the presence of rigor- ous controls of the same origin can the addition of water be satisfactorily determined, and the extent of the adulteration established. Ferments in Milk. 45 The experiments of Weigner and Yakuwa are of interest since they demonstrate that the refraction and specific eravity of the chloride of calcium serum are theoretically of equal value. Mai and Rothenfusser, on the other hand, emphasize the fact that of two theoretical methods of equal value the man in practice has to prefer the method which offers, with the same certainty of the results, greater advantages in regard to rapidity, convenience, and saving of material, advantages which the method of refrac- tion possesses. The investigations of Mai and Rothenfusser prove that the variations in the results of continued tests, from day to day may reach in mixed milk of one stable 0.1 to 0.55, and in longer periods (22 days), up to1.0. Changes of feeding have no marked influence. The milk of individual cows failed to show any important fluctua- tion during the time in which the tests of the entire stable were made (0.2 to 0.6). More considerable may be the fluctuation between the find- ings of normal milk and the secretion from cows with an affected udder, and the variation between the findings of milk from the same animal while healthy, and within 24 hours after the udder becomes diseased. The milk of individual animals with affected udders shows, not infrequently, values which are considerably below the values of normal milk. This has been proved by the work of Metzger, Fuchs, Jesser and Henkel, and from the experience of the official milk control station. These abnormal values, however, do not affect the worth of this method, if the results are compared through the use of satis- factory control tests, and confirmed by other methods. Ferments in Milk. Immune Bodies. Milk as Antigen. For the testing of milk special characteristics which it pos- sesses, which may be collected under the name of reaction manifes- tation of ferment action, and for which at present there is still no satisfactory explanation, are of importance. Under the term ferments (enzymes) those substances are included which hasten chemical changes with an explosion-like rapidity (Uexkuell), and without using themselves up they act in relatively minimal quantities. Their activity is inhibited by the products of the reaction. Higher degress of heat and certain toxins (ferment toxins, as for instance hydrocyanie acid) inhibit their activity, the ferments being thermolabile. The author desig- nates as ferments all of those bodies with ferment-like action, with- out ee as to whether the nature of the ferment is known or not. A careful distinction must be made between original fermen- 46 3iological, Chemical and Physical Characteristies of Milk. tative action and ferment-like bacterial activity sometimes taking place in milk. The original ‘‘ferments,’’ the nature of which is disputed, originate from the blood, or are formed from the cells of the blood and the parenchyma of the udder. They are either eliminated the same as products of metabolism into the surrounding parts, or they are anchored to the cell and are only set free in the breaking up of the cell (ecto- and endo-ferments). The ferments in their action are destined to certain substances to which they fit, ‘‘as the key fits the lock’’ (Fischer). They act either through hydrolytic splitting, through oxidation, or through reduction. Those ferments are of importance to the milk inspector, where diminished or increased presence or complete absence offers cer- tain conclusions as to various conditions in the udder or in the milk. These are the amylase (diastase), the indirect oxydase (per- oxydase), the superoxydase (catalase) and the indirect reductase (aldehydreductase, ‘‘aldehydeatalase’’). Besides those mentioned, milk also contains other bodies which are included among the ferments; for practical milk examinations, however, they have little or no bearing. Mention need only be made here of the proteolytic ferment, ‘‘ Galactase,’’ found by Babcock and Russell and bodies acting like pepsin or trypsin (Jensen, Freudenreich, Spolverini and others). These are only present in very small amounts. Kinase and fibrin ferment have also been demonstrated in milk. The proteolysis could be explained through the presence of leucocytes in the milk. Similar to the proteolytic ferments which cannot be utilized for diagnostic purposes, the lipase and the salol-splitting salolase (the existence of which as a ferment is dis- puted by Desmouliere, Miele and Willen; the alkaline reaction of various kinds of milk is sufficient to split up the salol) can not be likewise utilized for the purpose of di- agnosis. Rullmann in 1910 proved by the examination of aseptically drawn milk, that salolase is not an original ferment; the author considers the splitting of the salol to be the result of bacterial action. Of the ferments in milk which split up the ecarbo-hydrates, the amylase (diastase, galactoenzyme), whose action is similar to the ptyalin of saliva splitting up the polysaccharid starch into dex- trose and maltose, is of the greatest interest (Moro). This fer- ment was first found by Bechamp in the milk of women, later by Zaitscheck, Koning, Seligmann and others in cow’s milk. One hundred e. ec. of mixed milk can be split up by 0.015 to 0.020 gm. of amylase. Amylase is destroyed by heating for 30 minutes at 68 deg. C. (Koning) ; the optimum of its activity hes at 45 deg. C. The substances designated as oxydase and peroxydase exert a special action. They transmit the oxidation either by ‘‘activation of the oxygen of the air,’’ (direct oxida- tion) or by abstracting the active oxygen, for instance from peroxide of hydrogen (per- oxydase). Substances acting as reagents indicate their oxidation by the formation of coloring matter. The occurrence of direct oxydase in milk, the action of which appears even without peroxide of hydrogen, is uncertain. Rull- man has found traces of direct oxidation in milk drawn under sterile conditions; the quantity however is almost nil for practical purposes. The indirect oxydase acts only after the addition of hydro- gen peroxide or other oxygen carriers (for instance super-borates), Catalase. AT by abstracting active oxygen after the formula H.0.—=H,O+0 (Jensen). The active oxygen oxidizes the added ‘‘chromogenic’’ substances, as guaiacol, ursol, paraphenylendiamin, etc., to coloring matter. The peroxydase is injured by long heating, even at the relatively lower temperature (50-60-70 deg. C.), and is destroyed at about 75 deg., so that boiled or pasteurized milk may be dis- tinguished from raw milk by the non-appearance of the color reaction. The action of the superoxydase (Raudnitz) or catalase (Loew) develops in a different way. It splits the H.O, according to the formula 2 H,O.—2 H,0+20, which join to a molecule of O.. Other authors include the superoxydase with the oxidizing fer- ments, as the freed oxygen is utilized in the body for the oxidation (Seligmann). According to others it is included with reductase, as the action of the ferments on H.O. equals a reduction of 2 H.O, and molecular oxygen O. which passes out without being utilized for oxidation, whereas the oxygen freed by peroxydase is imme- diately utilized for further oxidation changes; therefore the per- oxydase is an oxidyzing, while the catalase is a reducing ferment (Grimmer). : Original catalase has been demonstrated in the milk of all animals ; it originates in the cells of the milk gland, especially from the leucocytes. It is secreted, but may be set free in the breaking down of cells or may appear bound to the cell. That catalase is derived from the cells (especially leucocytes) is not contradicted by the fact that cream is richer in catalase than skim milk since leucocytes and other cells are also included in the separation of the cream. These conditions were indicated by Friedjung, Hecht and Pallazzi, and later confirmed by Koning. This also explains the reason for the centrifuge foam, rich in leucocytes, giving such a strong reaction. Since the formed elements (cells) are precipitated with the casein, and probably a part of the free ferment is also drawn down with it, milk serum is always poorer in catalase than the original milk. Catalase passes through infusorial earth filters, but consider- able quantities are retained. Light, storage, ete., affect catalase, even if it is relatively resistant. A leucocytic extract, which was kept exposed to the light in the laboratory of the author, showed even after months, an unweakened action to H.02, while hydrogen sulphide, hydrocyanie acid, potassium eyanide, mereuric cyanide, barium nitrate, hydrochloric acid, sulphuric acid, acetic acid, oxalic acid, and potassium nitrate affected its action (Faitelowitz). It appears noteworthy that H.O, inhibits the ferment in its action. In the presence of excessive amounts of peroxide of hydrogen the ferment splits up less H.O, than if the diluted peroxide of hydro- gen is gradually added. Heating to 62-70° C. destroys the original catalase in a short time. The optimum temperature appears to be about 37 deg. C. 48 Biological, Chemical and Physical Characteristics of Milk. An original ‘‘ferment,’’ the nature of which is by no means definite, is Schardinger’s formalin methylene blue reductase, which according to .Trommsdorff, will be designated as Schardinger’s ferment (synonyms are indirect reductase, aldehydeatalase, alde- hydreductase). Fresh milk in a mixture of formalin and aqueous methylene blue solution (Schardinger’s re-agent), is decolorized inside of a few minutes. Smidt explains the action of Scharding- er’s ferment by the fact that the formalin changes into formie acid and thereby reduces the methylene blue. The character of its action however is not yet solved. The Schardinger ferment exerts its best action, at 65 to 70 deg. C., it is destroyed above 70 deg. As has already been indicated by Smidt and confirmed by Tromms- dorff, Schardinger’s ferment is very sensitive. It is injured by small excesses of formalin, and by relatively larger quantities it is destroyed. Romer and Sames established more recently, the interesting fact that boiled milk with 0.3 ¢. ¢. of a 1% of ferrosulphate solution also gives the reaction, and this disap- pears again when the mixture is boiled for a half hour. The authors point to the care which must be taken in judging the so-called enzyme reaction, since it is possible, with the aid of simple chemical reagents, to produce similar effects to those obtained in the supposed enzymatic reaction. Very little is known relative to the origin of the formalin re- ductase inmilk. This ferment is not in every sample of milk, being frequently absent in milk from an animal whose off-spring is still sucking, and in animals which are just fresh in milk (Schern). It is absent when the time of milking is over-extended, and in stasis of the milk (Romer and Sames), and it does not decolorize, or only incompletely so, in the first part of the milking, better in the middle of the milking, and rapidly in the last portion of the milk- ing. This also corresponds to the relative frequency of fat in milk but no one however has been able to establish a complete par- allelism. The authors conclude from this that the same conditions under which the gland excretes especially large amounts of fat, cause the quantity of Schardinger’s ferment to be likewise in- creased. Milk as Antigen and Carrier of Anti-Bodies. Since the fundamental experiments of Ehrlich relative to the formation of immune substances in the animal body, we possess an explanation for manifold manifestations between the inter-action of the disease-producing agent and the animal’s power of protec- tion, known as Ehrlich’s theory of immunity. The substances which are formed in the body in the com- bat against certain invaders are the anti-bodies; the harmful sub- stances which are capable of stimulating the body to the formation of anti-bodies are the antigens. Antigens may be substances of the most varied kinds; animal proteid, animal cells, plant cells, plant proteid, living and dead bae- teria, bacterial substances, toxins, ete. The antigens are distin- Antigen Action. 49 guished by groups, which make possible their combining with cer- - tain groups of the cell substances of the body. The ‘‘haptophore’’ groups of antigens under certain conditions fit as a key fits the lock, into the haptophore group of the ‘‘receptors,’’ thus making possible the binding of the antigens to the cell. These terms were applied to these bodies by Ehrlich. The simplest way of explaining the mechanism of the antigen action and the anti-body formation is by using toxin as an example. A toxin is an antigen with a haptophore binding group, and a poison-producing group, the toxophores. If the toxin enters the body of an animal it may find groups on the cell to which it fits, the so-called receptors, which bind its haptophore group. If this has been the case the toxophore group exerts its action, the effect of the toxin becomes noticeable and the animal suffers as a result of the toxin. If there are no receptors present for the specific toxin it is impossible for the toxin group to exert its action, and the animal is therefore resistant against this respective toxin. It is possible that as a result of the receptors of the cell com- bining with the toxin, the cell molecule is destroyed. But if the damage is not too serious, the protoplasm is stimulated to produce numerous receptors,—an over-production in fact. As not all of these are necessary for the performance of the cell function, the superfluous ones are rapidly thrown off into the body fluids. If such free receptors combine with the haptophore groups of the toxin, the latter is no longer able to combine with the protoplasm of the cell. These free receptors therefore protect the body against renewed action of the toxin, that is they act as antitoxins, and con- stitute the antitoxic part of the serum. Besides the antitoxins, the action of which lies principally in the neutralization of the binding group of the toxin (anti-bodies of the first order), there are still more complicated receptors, for instance those which possess an active or ferment-producing group; they are anti-bodies of the second order. Finally there are anti-bodies of the third order, which are unable to act by them- selves, but must utilize a third body in order to exert an action on the antigen. Immune bodies of the third order become complete in their action only through the utilization of the complement. These im- mune bodies of the third order possesss therefore a binding eroup for anchoring the antigen, and a binding group for the complement. They are amboceptors, in contradistinction to the uniceptors of the first and second order. Some anti-bodies resist heating for a half hour at 56 deg. C.; they are thermostabile, as for instance the antitoxins, the ageolu- tinins, the amboceptors, while others, as for instance the comple- ment, are destroyed at this temperature, as they are thermo-labile. _If, for instance, hemolytie anti-hodies are produced in a rabbit by treating the rabbit with red-blood corpuscles of another animal, then the hemolytic rabbit serum loses its action by heating to 56 deo. C, 4 50 Biological, Chemical and Physical Characteristics of Milk. The red blood corpuscles however are again dissolved when to the heated, ‘‘inacti- vated’’ rabbit serum, guinea-pig serum containing complement is added. Therefore, whereas neither the amboceptor in itself, nor the complement in itself can dissolve blood corpuscles, the combination of the two is capable of doing it. The action of the anti-body is specific for the substance which induced its formation, on homologous antigen. Diphtheria anti- toxin acts only on the toxins of the diphtheria bacillus, and not on the toxins of the tetanus bacillus. The specificity is a very high one, nevertheless it is only relative; that is, a similar, although somewhat weaker action is exerted on related antigen, as "compared with the specifie antigen. The chemical structure of the anti-bodies is unknown, and they are generally designated according to the action which they exert in the animal body. Anti-toxins neutralize toxins, agglutinins agelutinate (stick together) animal cells and bacteria, and drag them to the bottom, precipitins and coagulins produce precipitation in antigen solu- tions, hemolysins dissolve erythrocytes, bacteriolysins— dissolve bacteri ia, eytolysins dissolve animal cells, ete. If anti-bodies are produced by injecting antigens into an an- imal, then the animal is actively immunized against the antigen. On the other hand, if another animal is injected with the produced anti-bodies it is given a passive immunity. The active immunity lasts for a long time, the passive immunity does not last beyond several weeks. If anti-bodies are present in the blood in certain quantities they are excreted by the milk gland, and may be demonstrated in the milk. Ehrlich succeeded in proving the passing of anti-toxins into the milk of anti-toxic immune mothers, by showing that young mice from non-immune mothers acquired a high degree of resis- tance against the toxin when they were allowed to snieie actively- immunized mothers. The passing of anti-bodies into the milk even in the presence of passive immunity was proven by Ehrlich, Schmidt and Pflanz, although the passage was only slight. The action of such milk was 15 to 20 times weaker than that of the blood. Similar to the action of the anti-bodies of the first order are those of the uniceptors of the second order; for instance, bacterial agglutinins and precipitins. The passage of ag eelutinins from the blood into the milk has been demonstrated by Kraus, in goats which had been immunized against colon-bacilli, typhoid and cholera. The later works of Bensaude. Bertarelli, Bamberg and Brigsch, de Blasi, Courmont, Cade, Figari, Maragliano, Rodella, Staubli and others confirm the findings of Kraus. The agglutination value of milk, as compared with blood, may be lower or identical, or it may even be greater than that of the blood. As it has been found that bacterial agglutinins may pass into the milk, so it also has been proved that agglutinins against animal cells may do likewise. Complement Content of Milk. Al That under certain conditions amboceptors, as immune bodies of the third order, may pass into the milk, is proved by Bertarelli’s experiment on a sheep treated with the red blood corpuscles of a chicken. The specific hemolytic amboceptor which resulted could be demonstrated in the milk. Therefore although amboceptors may pass into the milk and although normal milk contains non- specific hemolytic amboceptors in small amounts, nevertheless the passing of hemolysins into the milk is very uncertain. According to Kraus, Kopf and others hemolysins do not occur in milk; like- wise bacteriolysins are absent, or their presence is very doubtful, according to the investigations of Bab. Of course one of the hemolytic factors, the amboceptors, might be present in the blood, while the complement under the special conditions present in milk, may be inactive. While Pfaundler and Moro state that hemolytic and bacterici- dal complement may be found in cows’ milk, Bauer and Kopf, and Bauer and Sassenhagen, on the other hand showed that in normal, ripe milk complements are not present; that is, even by special examinations only traces could be established. On the contrary in samples of colostral milk, and milk from udders affected with mastitis, both amboceptor and complement may be demonstrated. The complement content of milk drops with the duration of time which has elapsed between parturition and the taking of the sample, until from the sixth to the twenty-seventh day after ealving the amount of the complement disappears. This observation may possibly be of great practical value in ascertaining whether or not a cow is fresh in milk. Mastitis milk, which bears a close relation to colostral milk, showed a relative richness in amboceptor and in complement, thereby making it pos- sible to establish the affection of the udder by the demonstration of the complement. Of course it is not certain that the comple- ment occurs early enough to enable this method to be utilized more readily than for instance the Trommsdorff test, the catalase test, or microscopic examination of the centrifuged sediment, and others. Sassenhagen found in one case that the presence of mastitis could be determined by complement-fixation 18 days before the first clinical appearance of the disease, even when the quantity of sediment, after the Trommsdorff reaction wag insufficient to afford a basis for a diagnosis of mastitis. Bauer further proved that complement inhibiting substances are present in milk; Hausmann and Paseucci traced this inhibition of hemolysis to the presence of lecithin or cholesterin in the milk. According to Kopf the complement passes from the colostral milk into the blood of the calf ; it may be demonstrated in the serum of the calf from the third to the fourth day, before which time the blood cells of guinea pigs were not dissolved. Cr bo Biological, Chemical and Physical Characteristies of Milk. As proved by Kraus bacteriolytic immune bodies also pass into the milk, in artificially immunized animals, and into the body of the suckling consuming the milk, provided the mother possesses active immunity (de Blasi). Of other immune bodies which are present in the blood and have been demonstrated also in the milk of the same animal, should be mentioned the opsonins (Wright), which influence the bacterins in such a way that they may be readily assimilated by the phago- eytes (Turton and Appleton, Eisler and Sohma). Other substances which induce the so-called hypersensitive- ness (anaphylaxis), have also been demonstrated (Otto). At least it has been proven in the study of hypersensitiveness, that the off-spring of hypersensitized guinea pigs possess an increased sensitiveness for homologous antigens, and this may not only be the result of the intra-uterine transmission of the anaphylaxis from the mother to the young, but also of the transmission of the immune bodies, through the milk of the mother. To the subject of immune substances belong possibly the ob- servations made by Tage, Duhat and Dobrowits, during the treat- ment of nursing syphilitic mothers with salvarsan which shows its effect upon the untreated syphilitic children. Syphilitie chil- dren thrive splendidly after the treatment of their mother. It was impossible to demonstrate arsenic in the milk, either in or- ganic or non-organic combination. Ehrlich explains the action by the fact that a rapid breaking down of the syphilitic spiro- chaetes in the mother is produced through the action of the new syphilitic remedy, and thereby an elimination of the endo-toxins is induced. The antitoxins which develop in the mothers pass into the milk, and cause a passive immunization of the child, through the gastro-intestinal tract; Jesionek, on the other hand claims the passage of the arsenic from the blood of the treated mother to the milk, and explains thereby the remarkable results in untreated children which are nursed by the treated mothers. Very little is known with certainty relative to the quantita- tive relation which exists between the immune bodies appearing in the cirecluating blood, and those in the milk. The views expressed are too widely divergent. It is known of the anti-toxins in which this relation has been mostly studied, that of 15 to 30 parts of the anti-bodies which are demonstrable in the blood a certain amount appears in the milk. These relations are still somewhat vague, since the passing of the anti-bodies which are bound to the albumins and globulins depends on the quantitative relation of these proteids in the milk, and the experimental results therefore must vary in accordance with the species of animal used, the stage of lactation of the respective individual, diseases of the udder, ete. In infections of the udder, for instance with colon bacilli, anti- Agressins. D3 bodies accumulate in the glands so that as a result the milk serum agelutinates more readily than the blood serum. Not only anti-toxins and other protective immune bodies pass into the milk, but substances also which inhibit the protective power of the body, for instance aggressins, at least so long as the body has not formed anti-aggressins. The aggressins for instance act against the dissolving of bacteria. Schenk demonstrated anti- staphylolysins and anti-vibriolysins in the milk of goats, cows and women. Otherwise the passage of toxic substances of the character of antigen, which are closely allied to proteids, could be just as plausible as the passage of the constituents of the blood which are indispensable in the composition of the milk. The passage of toxins into the milk has not yet been satisfactorily proven for all toxins. A large number of known substances from animal and plant life are known as toxins, that is, bodies which do not act like ehemical poisons, but exert their toxic action only after a period of incubation, in which time fixation takes place. These toxins do not affect all animals in a similar degree, but only those which are susceptible. Certain species of animals are not susceptible to certain toxins; they are immune. This im- munity may also be artifically established in susceptible animals. The toxin is an antigen, and under certain conditions it produces an anti-toxin contrary to the toxins which act purely chemically. Among toxins acting in this manner may be mentioned the products of metabolism of the Bacillus diphtheria, the Bacillus tetami, the bacillus of certain forms of meat poisoning—the Bacillus botulinus and the Bacillus pyocyaneus, the bacillus of blackleg, and the body substances of certain bacteria (endo-toxins). They may be of animal origin: snake toxins, spider toxins, scor- pion toxins, turtle toxins, toxin of the blood of eels, salamander toxins, wasp toxins, or of plant origin, such as the abrin, robin, krotin, ricin, ete. If it is considered that the gastro-intestinal tract of very young individuals is readily penetrable for proteids, although pro- teids of unlike origin pass with greater difficulty than those of like origin, the question as to whether the milk of the mother may con- tain toxins when toxins are circulating in her blood, assumes prac- tical importance. This becomes, however, unimportant when it is considered that even in severely affected individuals only very small quantities of toxins are circulating free in the blood. Should a part of these minute amounts be secreted in the milk, this quan- tity itself is of only little practical importance even when the great susceptibility of the intestines of the suckling is considered. It is true that Miessner succeeded in proving that mice die from tetanus when they are fed with raw milk from a cow affected with tetanus, whereas the feeding of meat has no influence on the 54. Biological, Chemical and Physical Characteristics of Milk. health of the animal; this proves the passage of the tetanus toxin into the milk. Older animals do not become affected even after the adminis- tration per os of large doses of toxins, at least not from diphtheria or tetanus toxins, and the Bacillus botulinus, the toxins of which are absorbed by the stomach but the bacillus does not thrive in the body; therefore the possibility of secreting these toxins through the milk gland is from the first of small importance, especially since in severely affected animals the secretion ceases. From a practical consideration of the question of toxin elimi- nation, the plant toxins come principally into consideration, espe- cially ricin, as food adulterations to a great extent take place with ricinus seed and its flower. An elimination of ricin with the milk, however, has not been observed up to the present time. Ehrlich was unable to observe an elimination of ricin in mice which were under the action of ricin; the offspring of. these mice were not actively immunized against ricin but acquired only a passive im- munity of short duration. Of more importance however are the bacterial toxins, and products of decomposition acting like toxins, which subsequently develop in the milk after certain fermentation processes. The above-mentioned immune substances are probably of great importance for the nourishment of the young and the sucklings. The passage of genuine proteids in very young individuals with injured mucous membranes, is an established fact, and with the elobulins anti-bodies also pass into the blood of the young, while in older individuals the relatively labile anti-bodies are changed or destroyed by the splitting up of the proteids. The absorption of anti-toxins through the intestines of the young has been proved by the classical experiments on sucklings by Ehrlich. Other works by Brieger, Ehrlich, Salge and Romer prove that certain immune substances of milk of Tike origin pass through the intestines, while in feeding sera or anti- substances of like origin contained in milk of unlike origin the quantity passed was only very slight. Thus Romer succeeded in demonstrating passive immunity in foals after feeding them with anti-toxin milk of like origin, but was unsuccessful after feeding anti-toxic sera of like origin. In calves of course the results were positive even when the anti-toxin was mixed with the milk as a serum of unlike origin, but the quantity of immune bodies of unlike origin absorbed was smaller than that of like origin. The absorption diminishes with the increase of the age of the animal. Relative to the passage of other immune substances from the milk into the blood of the suckling, the same experiences hold as a rule as in the ease of milk containing anti-toxin. Milk is not only a carrier of anti- bodies, and possibly of anti- Acute purulent fibrinous mastitis. Dilation of the blood vessels (c); with exudate of numerous cells into the alveoli and excretory duct. Hematoxylin—Sudan III. Concrement -formation in milk stasis (a), and in mastitis (b); inactive portion of the gland (c). Ernst, Milk Hygiene. Precipitin. 55 gen, but as a proteid-containing material it is an antigen in itself, or rather a collection of antigens, which may again produce anti- bodies in the body of an animal. These anti-bodies against milk not only develop in artificial administration by injections, but also under certain conditions during the natural ingestion of the milk per os asa food. Although usually such anti-bodies against nutri- tive proteids of unlike origin appear only in intensive over-feeding of proteids (Ascoli, Michaelis and Oppenheimer, Uhlenhuth, and others), nevertheless in the presence of an injured intestinal mucous membrane the absorption of proteids of unlike origin may, under natural conditions, take place, and thereby induce the for- mation of anti-substances. Moro succeeded in finding cow milk precipitin in two instances, and milk proteid in one instance in an examination of 22 anemic bottle-fed children. . Bauer found precipitating substances of cow’s milk in the blood of an emaciated man. Kentzler, with the aid of the precipitation test, demonstrated milk proteids in the blood of six human subjects in which the gas- trie secretion was disturbed, out of 61 cases that he examined two to three hours after feeding. Although milk is absorbed through the intestines of older individuals only after the splitting up of the proteids, nevertheless in case of an injured mucous membrane, or in greatly emaciated and in very young individuals the direct absorption of unchanged proteids is possible. Ganghofner and Langer succeeded in proving this on very young rabbits, on pigs and on newly born eats, and they succeeded also in demonstrating a precipitin formation in the blood. Schkarin describes similar results after the feeding of eow’s milk to young rabbits. Lactoserum. It will be advisable and appropriate to include at this place a subject which as a matter of fact belongs to the chapter dealing with the characteristics of the milk of various species of animals. Milk is an antigen and contains various antigens. After injecting the milk of species A into an individual of species B, the formation of various anti-bodies, precipitins, amboceptors, ete., may be ob- served in the blood serum of the treated individual, which gives to the blood serum the specific characteristics of lactoserum. This specific characteristic is shown by the fact that the cow lacto- serum of rabbits produces a precipitation only when cow’s milk is used for the precipitation, but not with milk of women or goats. Works of Bordet, Fish, Morgenroth, Wassermann and Schiitze show the specific action of lactosera. With the aid of such sera the possibility is afforded of differentiating the milk from various species of animals. 56 Biological, Chemical and Physical Characteristies of Milk. This however does not end the degree of the specificity, as it is possible with the aid of the precipitation method to differentiate various kinds of proteids of one and the same milk. If the soluble proteid bodies are separated from the undissolved casein by filtration (Schlossmann), then the rabbits which are treated with soluble proteid bodies furnish sera which react only to milk albumin and globulin (Hamburger). It is of further interest that cow-casein sera gave precipitation with eattle blood (Hamburger), the same as is the case with lae- tosera (Landsteimer, Halban, Dungern, IF’. Meyer, L. Aschoff). Moreover lactosera immobilizes spermatozoa of bulls, and dissolves red blood corpuscles of cattle. However no reaction results from the addition of cattle blood serum containing anti- bodies to cow milk (Meyer). The anti-serum sensitized against cattle blood only gives slight precipitation when it possesses espe- cially high value (Uhlenhuth and Schiitze). The same conditions were found in preparations of human blood, and women’s milk, by Halban and Landsteiner. Uhlenhuth and Schiitze proved that the differentiation of various kinds of milk shows that the biological method succeeds even when the milk is heated to a high temperature (114 deg. C. in an autoclave) ; if the milk antigen was heated 20 minutes at 120 deg. C., lactosera resulted, which only contained coagulins, but no hemolysins. Sion and Laptes showed that the most varied splitting and decomposing changes of cheese-making and cheese-ripening do not influence the antigen to such an extent that the kind of milk used in making the cheese could not be determined by the biological method. This specificity is of course manifested even in the use of lactosera, but is not absolute, only relative. Lactosera also gave a reaction with the milk of closely related animals, the same as has been established for blood sera, meat sera, ete. Thus for in- stance it is impossible to differentiate sheep’s milk from goat’s milk (Uhlenhuth, Moro, Gengou), although it is possible to draw conclusions from the comparison of the intensity of the reaction in the homologous milk. Other authors, as for instance Bauer, succeeded in demonstrat- ing by the so-called complement-fixation method, the presence of cow’s milk in woman’s milk, even when only 1 «¢. e. of the former had been added to 1000 e. ec. of the latter. If specific serum which has been heated for a half hour at 57 deg. C. is mixed with milk and as much complement is added as is necessary for the dissolving of the subsequently added blood corpuscle suspension, with the aid of certain quantities of hemo- lytic amboceptors, then the amboceptors of the lactoserum bind the complement, provided they find in the milk the specific antigen (cow lactoserum-cow milk), and the subsequently added hemolytic system, free of complement, no longer finds complement, so hemo- lysis does not occur, but instead fixation of complement results. If there is no specific antigen present (if the milk to be examined con- tains no cow milk), the complement remains free to be utilized later by the hemolytic amboceptors and the blood cells, for the Anophylaxia. SVT functionating hemolytic system, and a solution of the blood—hemo- lysis—results. The appearance of ‘‘anaphylaxia’’ may also be produced ex- perimentally with milk (Arthus and Besredka). It may be brought on by raw as well as by boiled milk. 99 The phenomenon of hypersensitiveness as is known, results when a proteid of un- like origin is injected into an animal and later after a period of time the same proteid is re-injected. At the second injection (or only after later ones, depending on the ex- perimental animal and the quantity of proteid), the experimental animal reacts violently with indications of extreme sickness (Von Behring, Richet and Arthus), which may even result in death from convulsions and pulmonary edema. Miessner succeeded in producing a hypersensitiveness against homologous kinds of milk in guinea pigs, sometimes after one in- jection, but more markedly after repeated subcutaneous injec- tions, and with the greatest certainty after intra-abdominal in- jections of small quantities of raw milk. The best reaction was obtained in the animals after three intra-abdominal injections of .d c. c. of milk, on three successive days. After the preparation of the animal 40 to 50 days should elapse before the test which is made by intra-cardial injections. After repeated injections it is possible to demonstrate an ana- phylaxis in most cases even with boiled milk. In order to utilize the biological test for milk differentiation several rabbits should be prepared. This is carried out by in- travenous injections of small quantities (5 or more e. ¢.) of milk heated for a long time to 65. deg. C. The injection is repeated 5 to 8 times at intervals of 1 to 4 days. In from 14 to 20 days after the last injection the lactoserum may be tested for its effectiveness and if found suitable, may then be drawn. For this purpose the animal is kept without food for one-half day, (in order not to obtain a cloudy serum), a venous hyperemia of the ear is produced by intensive lighting of the ear with the aid of an electric globe, or by rubbing it with xylol, and the vein is then punctured with a fine hypodermic needle. Several cubic centimeters of blood are drawn, which is allowed to coagulate; the blood clot is separated and allowed to stand for 24 hours in an ice chest. The test is made as follows: _ I. Establish the dilutions of the serum which are capable of producing a visible precipitation in 3 ¢. c. of milk dilution, with 1:60 physiological salt solution, or 2. Hstablish the dilution of milk with 1:10 physiological salt solution, in which when mixed in the relation of 1:6, the lacto- serum still produces a precipitation. The most active lactoserum is the best adapted for use. The rabbit is bled to death (slight anesthesia-opening of the thorax-puncturing of the heart), the blood for the collection of the serum 1s allowed to stand, the serum is drawn off in quantities of 2 to 5 ¢. ¢. into small vials, and placed in an ice box for safekeeping. CHAPTER V. PROCUREMENT OF COW’S MILK. As has already been mentioned milk secretion may be retained for a long time by proper emptying of the gland and by the stimu- lation exerted on the gland in the process of emptying. In the presence of incomplete milking, in over-extending the time of milking, and in stasis of the milk, a condition of the gland results, which finally passes into a state of inactivity, when the stimulating condition which is exerted by the retention of the secretion on the secreting epithelia does not again appear with the act of a com- plete milking. The milk secretion therefore is largely dependent on the activity which is exerted on the gland from the outside, such as the sucking act of the calf, or artificial milking. Artificial emptying is carried out in various ways: 1. By closing the upper portion of the teat with the aid of the thumb and index finger, and pressing out the contents of the cis- tern by gradual closing of the hand to a fist in such a way that first the middle finger, then the ring finger, and finally the small finger presses the milk downward and from the opening of the teat. The open hand is passed up again, forcing the milk into the cistern from the upper part of the quarter, the thumb and index finger again squeeze the cistern at its base, and the procedure ends as before. This manipulation is known as ‘‘fisting’’ or full handed milking. 2. By stroking with the closed thumb and index finger from the base of the teat to its point the milk may also be pressed out (‘‘stripping’’ or ‘‘tipping’’). This method of milking requires much less strength than the full handed milking, but causes a lengthening of the teats, and is a painful operation for the animal, as it is frequently accompanied by injuries to the tissue, and tear- ing of the mucous membrane. The full handed milking may be carried out by dry milking, while ‘‘stripping’’ succeeds only when the teat and hand are moistened (moist milking’), since the necessary smoothness and slipperiness of the skin result only from moistening. If the teat is not pressed with the extended thumb (a brace for the index finger), but the thumb is crooked and the teat is pressed and stringed with the bent index finger against the nail surface of the thumb and the knuckle of the joint, this is spoken of 58 | Methods of Milking. 59 as ‘‘streak milking’ or stripping with bent thumb. The ‘‘streak milking’’ may be completed by stripping or by full handed milking. Full handed milking and this method combined with ‘‘streak milk- ing’? are according to Henkel permissible; the other kind of milking should be prohibited since the teats are too much extended. The udder should be milked by the dry method since this method of milking is more cleanly than moist milking, in which the fingers become moistened by the milk, and although they slip easily, at the same time they wash off the dirt from the entire teat. It is to be regretted that moist milking and stripping because of their labor saving advantages, are preferred by many milkers on account of their convenience, and even if they are urged to carry out the ordinary dry milking, as soon as they are left with- out supervision they will at once fall into the same fault. The order of milking the various teats differs. Milking from the same side is supposed to induce the development of the side first milked, since the half of the udder first milked is worked with fresh strength while the subsequently milked quarters are not emptied as well on account of the beginning weariness of the milker and therefore they develop less perfectly. The hind quar- ters are either not emptied entirely when the milkers have com- pleted the milking of the fore quarters, or else one hand of the milker rests while he finishes milking the hind quarter with the other. The same applies in milking the teats crosswise, when the hind quarter of one side of the udder is milked at the same time as the fore quarter of the other side. Therefore it is advisable to milk the fore quarters together and the hind quarters together, and the milking should be undertaken first on those quarters which appear to be most distended. With the drawing of the milk from the udder through milking the teats, the complete act of milking is not concluded, as the udder has not yet been sufficiently exhausted in its production. The cause of this may lie in the fact that the milk cannot be emptied by the simple sucking action from the smallest milk ducts and alveoli, or that after the apparent entire emptying, the milk pro- duction still goes on if the gland cells are properly stimulated in their functions. As the flowing in of milk may be accomplished through the so-called ‘‘preparation,’’ that is stroking or massage of the bases of the teats and quarters, the same result is possible through the so-called ‘‘clean milking,’’ or ‘‘after milking,’’ to obtain an addi- tional quantity, which is especially rich in fat. These methods vary and are practiced in different ways in dif- ferent localities. The best known method of ‘‘clean milking,’’ and one which has been mostly studied, is that practiced by Hegelund, a Danish veterinarian. This method is divided into the following phases: 60 Procurement of Cow’s Milk. 1. Milking through simultaneous full handed milking, first of the fore and then of the hind teats, until the milk flows no longer. 2. This milking is followed by the ‘‘clean milking,’’ which consists in massaging the udder, beginning at the teat up to the base of the teat, and as high as possible extending on to the paren- echyma. While the first act corresponds with the usual full handed milking, the second act massages with a milking motion, the base of the cistern, and the third is carried out by surrounding between the thumb and the hand, and stroking down the lower part of the quarter, that is, through simultaneous pressing against each other of both quarters of opposing’ sides. 3. The first manipulation of the after milking is carried out by pressing the right quarters of the udder against each other, the left hand being placed on the hind quarter and the right hand on the fore quarter. In case of a large udder, only one quarter is grasped at one time. The hands are then pressed upwards with a rubbing motion on the gland which exerts a massage on the par- enchyma of the udder, this being repeated three times, followed by milking out the cistern. This manipulation is repeated until no more milk is obtained, when the left quarters are treated in a similar manner. In the second manipulation the fore quarters are milked by placing one hand on the outside of the quarter and the other in the division between the two fore quarters. The hands are pressed against each other followed by milking of the teats. Then the hind quarters are milked by placing a hand on the outside of each quarter in such a way that the fingers are turned upwards and the thumb placed in front of the hind quarter. The hands grasp the quarter and are pressed upward; then they are lowered and the milking follows. This is also repeated until no more milk is obtained. In the third manipulation the milker imitates the butting mo- tions of a calf during sucking. The hands loosely surround the teats and the quarters are lifted and pushed against the abdominal] wall so that the gland tissue is shaken. This lifting and pushing motion is repeated three times and the teats are then milked out. Following this procedure on the fore quarters the hind quarters are treated in a like manner, until no more milk is ob- tained. The works of Aashamar, Alfonsus, Woll, van der Zande and Henkel, and Wenk, speak of the excellence of the method of Hegelund. According to Henkel the increase of the milk yield in 37 Simmenthal cows was 217.4 em. (3.4%) per milking on an aver- age. Wenk succeeded in obtaining from 24 cows 4.5 kg. of milk per day more than with the ordinary method of milking. Of course against the increase of yield must be placed the Methods of Milking. 61 additional work and time, which is an additional expense and considerably diminishes the profit derived from the increased yield of milk, and may even nullify it, since it involves the employment of additional help. The principal advantages of Hegelund’s meth- od lie in the fact that the milkers are held down to thorough work, and the milk glands are subjected to more correct and appropriate handling. A modified form of Hegelund’s method is the so-called ‘‘New Algauer milking method,’’ which combines the acts of the Algauer method with those of Hegelund. The massage of each quarter is carried out with both hands. The method of Sondergaard aims to simplify the time-consuming work of ‘‘clean milking’’ inasmuch as the residual milk is obtained by a wide extensive hold of the halves of the udder at their bases, and pressing at the same time and stroking downwards. The principal factor in each method of milking is that the udder should be thoroughly emptied, and this can only take place when each part of the milk gland is stimu- lated by massage to the limit of its production. CHapTer VI. INTERNAL INFLUENCES ON THE CHARACTER OF MILK. The influences which must be considered in the formation of milk may be separated into internal influences which le in the individual characteristics and in the immediate condition of health of the animal, and in outside influences, such as stabling, feeding, ete., which again act only in that they influence the internal condition. As internal influences may be considered the characteristics of the breeds, strains, family, individual, age, influences of the lactation period, pregnancy, and the general and local conditions of health. The outside influences may be considered under care and attendance, feed, medical treatment, climatic influences, meth- ods of milking, ete. Following this outline the internal influences on the formation of milk will be considered first. Breed, Family, Heredity, Individual Characteristics. Age, Lactation and Other Special Conditions of the Individuals. The influence of the breed on milk formation is generally known. There are beef breeds which fatten especially well, milk breeds in which milk production is especially preminent, and breeds which possess the ability to produce both milk and meat. Breeds of low lands and their crosses produce more milk with lower percentage of fat than breeds from the highlands. 1.082) 3.05 2.99 4:24 silsG2 sees Oz a0 BO ee oi a 2.97 3.63 Is .00s sien Ge 38-9 030m. 43 2.99 3.80 12°3Iee about 8 ** 39.0 1.0380 3.43 3.04 3:91) “Alt Ssaaee 8—10** 38.6 1.031 3.06. 3.04 4.15 DIO Oe Oe SS. 4 OL a9 o.1 4.49 12.03 0.69 about 10 ** 38.6 1.030 2.84 3.19 - 42:57 dil2iaaaeee 10 — 11 **. 38.5 1.032 3.45 3.24 4.41 ~ TIl7eee about 12 “* 88.4: 1.031 3.25: 3.33 4138-0 125303 It appears also from the other investigations of Honigmund, in which the animals showed symptoms of the disease as early as on the first day of the examination, that the fat and ash content is greater in the first day than in normal conditions. The total solids and also the fat-free solids fluctuate considerably. When eatarrh of the milk ducts becomes associated with foot- and-mouth disease, the milk becomes yellowish, of a rancid, bitter taste, colostrum-like, and similar to the secretion during other in- Foot-and-Mouth Disease. 73 flammatory conditions of the udder, that is, slimy, watery, and in- termixed with coagulum. It is an important fact that milk from animals which are af- fected with foot-and-mouth disease will contain the virus of foot- and-mouth disease, if it has been contaminated by the vesicular contents. Nocard succeeded in proving, however, by careful ster- ile drawing of the milk from cows affected with foot-and-mouth disease, that the milk does not contain the virus of foot-and-mouth disease as it leaves the udder. Nevertheless it is not satisfactorily proved that a direct elimination of the virus may not take place at the beginning of the febrile state, as at this time the virus is present in the blood. If the udder itself is affected by the eruptions of foot-and-mouth disease it is hardly possible to avoid contamination of the milk with the vesicular contents. Considering the ease with which the virus of the disease is spread, it may be assumed that the entire milk of a herd affected by the disease, under ordinary conditions of milk production, contains the contagion of foot-and-mouth disease. Strict veterinary police measures must be inaugurated to prevent the spread of the disease. Sale of the milk should be permitted only after sufficient heating. The maintenance of a temperature of 70 deg. C. for one-half hour will make the milk perfectly safe. Milk containing the living virus of foot-and-mouth disease must be considered deleterious to human health, since it has been established by experiments and observations that the disease is transmissible to human beings. Vesicular and ulcerated inflam- matory changes of the buccal mucous membrane with fever and general symptoms develop with possible vesicles and ulcers on the hands, arms, breast, lips, ears, and in the throat. Vomiting and diarrhea may be associated with symptoms of a gastro-intestinal inflammation, and the affection may even terminate in death. (Bus- Senius and Siegel, Jensen, annual reports of the Imperial Board of Health, Hertwig, Stickler, Schreyer, Krajewski, Walkowski, and others). Bongert suggests the separation in dairy stables of the non-affected, slightly and Severely affected animals into isolated eroups, and in order to reduce the economic losses as low as pos- sible, the milk of these groups should be treated in different ways. Heated milk from the non-affected animals for instance, could be utilized as infant’s milk. The milk from slightly affected animals could be marketed as ordinary milk [after pasteurization], while the milk from the severely affected cows or milk changed in its consistence, should be excluded from consumption even in a heated condition. Even with this separation the losses will necessarily be high as a result of the enforcement of stringent sanitary regu- lations. According to Ebert sour milk 3 to 4 days old is no longer capable of transmitting the infection. The transmission is possi- 74 Effect of Internal Influences. ble through cheese and butter (Frohner, Ebstein, Thiele, Schnei- der, Frick, Frohlich). The general rules which have been indicated above obtain also in changes of the milk in malignant cedema, blackleg, or parturient blackleg of cattle. Transmission of these diseases through the consumption of milk from affected cattle, or through the diseased products of contaminated milk, is not to be feared; besides milk production ceases very rapidly in the affected animals. The same rules should apply in judging milk from animals affected with hemorrhagic septicemia, a disease which is pro- duced by a bi-polar bacterium. This disease is transmissible to calves, through sucking or feeding milk from affected animals. Anthrax of cattle should also be mentioned. This runs in an acute or sub-acute form, and as a rule is associated with a sudden cessation of the milk secretion, which occurs even as early as at the beginning of the fever. The anthrax bacilli only multiply towards the end of the disease sufficiently to cause a direct passage from the blood into the milk. If the secretion has continued to some extent this direct passage is possible even if no hemorrhages, such as are typical during the course of anthrax, have developed in the parenchyma of the udder. The demonstration of anthrax bacilli in milk has been accomplished microscopically, and by inoculation and cultural experiments, but not in all the cases which have been examined (Bollinger, Chambrellent and Mous- sou, Feser, Monatzkow). In severe cases the milk becomes yellowish, bloody and slimy. At the appearance of the fever the fat and sugar contents are in- creased, while the proteid contents are diminished. The danger of infection through the ingestion of raw milk con- taining bacilli is slight, since the anthrax bacilli are digested by the gastric juice. More dangerous than the bacilli which may pass into the milk from the blood are the anthrax spores which may reach the milk through contamination with manure of affected animals, or through straw and stable dust, since the resistant spores are not destroyed by the gastric digestion. The virus may also be present at times in normally healthy animals after they ingest food containing anthrax spores.. The milk may hecome infective through contamination with feces from such bacilli ear- riers. In spite of the fact that there are remarkably frequent opportunities to obtain milk with bacilli and spores from localities in which anthrax persists epizootically as a disease of the soil, yet only one anthrax infection of man is known to have occurred through the ingestion of milk. This resulted in a patient with typhoid fever, who after drinking 11% liters of milk became affected with intestinal anthrax. The milk was derived from a cow with a malignant pustule on the udder, which had died in the meantime from anthrax. Rabies. 79 Lehnert states that the calf of a cow affected with anthrax re- mains well, although it may suck the mother through the entire course of the disease. Even though milk offers a splendid nutritive medium for the anthrax bacillus, an increase of bacilli only occurs during the first three hours. Keeping the milk at room temperature for 18 to 24 hours, is followed by the death of the bacilli (Caro). At the beginning of souring the vegetative forms of the virus are quickly destroyed; the spores however remain active (Inghilleri). If anthrax bacilli are cultivated in milk, coagulation occurs under the rennet action of the peptonizing bacterial ferments. The coagulum again slowly dissolves, and the milk separates into fat and whey. Less important than anthrax is rabies, as this disease occurs much more rarely in cows. According to Nocard and Bardach the milk of animals affected with rabies contains the virus. Never- theless the danger to man from the ingestion of such milk is hardly probable, since it is impossible to affect experiment animals by feeding fresh milk (exceptions are rats and mice). A nursing infant of a woman affected with rabies remained well, although it was fed with the milk of the patient until one day before her death (Bardach). The uninjured mucous membrane of the mouth, pharynx, and the intestinal tract does not offer opportunity for infection. This opportunity is afforded only when destruction of tissue and small wounds permit the entrance of the contagion. Thus for instance Galtier succeeded in producing rabies through rubbing brain material of rabid animals into the mucous mem- brane of rabbits. According to the observations of Virschikowsky the rabid virus is destroyed by the gastric juice. Very little, or nothing at all is known relative to the special relationship of other infectious diseases to milk, as for instance malignant catarrhal fever, croup of cattle, the blood diseases of eattle caused by spirochetes, trypanosomes and piroplasma, or in- fectious vaginal catarrh and infectious abortion. In the presence of infectious vaginal catarrh and contagious abortion the milk secretion 1s supposed to be diminished. It should be remembered that in such affections the passing of the disease agents from the blood into the milk is possible. [That the bacillus of infectious abortion is eliminated by the milk has been definitely established. See Bureau of Animal Industry Circular No. 216]. In a ease of icterus in a woman Mayer observed the passage of bile acids, especially taurocholic acid into her milk. Finally two other diseases should be mentioned which may be transmitted from animal to man: 1. Milk Sickness. A rather peculiar disease, called ‘‘milk sickness,’’ is found in the central part of the United States, where it at times occurs as an epidemic among cattle and people. In cattle, the first indication of disease is dullness, followed by violent 76 Effeet of Internal Influenees. trembling and great weakness, which increases during the sue- ceeding day until the animal becomes paralyzed and dies. Through the ingestion of flesh, milk, or dairy products of an affected animal the disease is transmitted to man or to another animal, and at- tacks produced in this way most frequently prove fatal. In man the disease develops with marked weariness, vomiting, retching, and insatiable thirst. Respirations become labored, peristalsis ceases, the temperature is subnormal, and the patient becomes apathetic. Paralysis gradually follows and death takes place quietly without rigor mortis. Many etforts have been made to elucidate the question re- garding the nature and cause of this disease, but although many theories have been discussed none of them has so far been general- ly accepted. Some investigators hold that the disease is of micro- organismal origin, some that it is due to auto-intoxication, while others think it is caused by vegetable or mineral poisons All seem to agree, however, that the disease is limited to low, swampy, uncultivated land, and that the area of the places where it occurs is often restricted to one or a few acres. Furthermore, when such land or pastures have been cultivated and drained the disease dis- appears completely. The discovery of a new focus of this disease in the Pecos Val- ley of New Mexico in November, 1907, gave Jordan and Harris the opportunity of studying this peculiar affection by modern bacter- iological methods. As a result they have succeeded in isolating in pure cultures from the blood and organs of animals dead of this disease a spore-forming bacillus which they name ‘‘ Bacillus lactimorbi.’? With this bacillus they have reproduced in experi- ment animals the symptoms and lesions peculiar to milk sickness or trembles, and from these animals the same organism has been recovered in purity. It therefore appears to have been demon- strated that the bacillus in question is the probable cause of the disease. As Jordan and Harris have already indicated, more com- prehensive studies, based on a larger supply of material, are desirable in order that the many obscure and mystifying features connected with the etiology of this rapidly disappearing disease may be elucidated. From the above facts it seems evident that milk sickness is an infectious disease communicable to man, and the cattle owners should therefore not be permitted to make use of the meat or milk of affected animals for human consumption. Trans. ] 2. Malta Fever. On the coast of the Mediterranean. in South Africa, India, China, Philippines, America, and especially on the Island of Malta, there occurs in goats a disease which exists in the animals without producing any or at most only very slight symptoms. Cows may also possibly be affected. The infected animals eliminate for months, frequently at intermittent periods, the virus of the disease (Micrococcus melitensis, Bruce). Follow- Mastitis. 77 ing the ingestion of such milk ‘‘Malta Fever’? develops in man. It has a protracted course with recurrences, and is accompanied by anemia, headaches, rheumatic pains, constipation and swelling of the joints. Malta fever terminates fatally in about 3% of the cases. The goats show on postmortem, swelling of the spleen and lymph glands, frequently also inflammations of the kidneys and lobular pneumonia. The virus is relatively resistant against souring of the milk, but at 70 deg. C. it dies in 10 minutes. According to Zammit about 10% of all the goats on the Island of Malta eliminate the virus, while 50% of the animals show by the agglutination test that they are or have been under the influ- ence of the Micrococcus melitensis. We are in possession of better information concerning the changes which milk undergoes in inflammations of the udder than we have regarding the effect on the milk secretion as a result of general diseases, or regarding the importance of milk from affected animals from a hygienic standpoint. Changes in Appearance, Consistence, Contents, Etc., During an Attack of Mastitis. Relatively very little is known as to the influence of the dis- eases of the udder on the chemical and physical character of the milk, although it is well known that with the changes in function and condition of the organ the product is also changed, as com- pared with the product of the normal gland. Even in the same disease the product varies in accordance with the intensity, dura- tion and the extension of the disease, the same as it naturally varies in accordance with the nature of the injury to which the parenchyma is subjected. As a result of these conditions the re- sults of the data of different authors vary considerably. It may be said in general that in affections of the udder the proportion of the proteids, sugar, salt, fat, and enzymes in the milk becomes altered and that the relation of the individual pro- teids, the salts and the enzymes, also undergoes fluctuations. In acute and greatly extended chronic inflammations, both fluid and cellular constituents of the blood may pass into the milk, cells of the parenchyma are thrown off, coagulation sets in, and briefly, the milk changes more or less rapidly in appearance, taste and contents, so that it deviates considerably from the milk of healthy cows. At times none of these characteristics appears, especially in the early stages of chronic inflammations of the udder, or after the subsidence of the acute Symptoms, and it is then only possible with the aid of certain methods of examination to differentiate such affected milk from normal. Therefore of special importance to milk hygiene are the chronic inflammations, and inflammatory stages in which the 78 Effect of Internal Influences. changes of the secretion appear slowly, and relatively late, while inflammations of an acute character very quickly produce a tre- mendous change in the secretion, the mixing of which with market milk would be the grossest negligence. It is to be regretted that such cases occur. Appearance of affected milk: In forms of inflammation which are associated with rapid development, painful swelling and in- creased temperature of the udder, the milk usually has a bloody discoloration, later becoming yellow (colostrum-like), and finally changes into a eustard, or honey-like secretion, in which thick, yellow and yellowish-brown flakes are suspended in a more or less clear serum or plasma. Such changes are observed in samples of milk in acute forms of mastitis, through infection of bacteria of the colon group, in mixed infections, in acute attacks or in great extension of strep- tocoecic mastitis, and in infections with the Bacillus pyogenes, ete. In chronie affections the milk changes only slightly or not at all during the beginning of the disease, or it may appear normal long before the disease as such is considered cured. If such nor- mal appearing milk from affected quarters is allowed to stand for several hours a white, yellowish-white or yellowish sediment settles to the bottom. At the same time the quantity of cream is increased and changed, appearing yellowish, tenacious, and when shaken it assumes a cloudy or wavy appearance. If the migration of the pus corpuscles from the blood vessels becomes more inten- sive the milk appears thick, yellowish, cream-like, and after stand- ing separates into a yellowish-white to ocher colored sediment, which may amount to two-thirds or more of the entire mass, and into a dark, transparent, yellowish-grey to greenish-yellow skim milk. The sediment layer is at times increased, at other times decreased. The cream becomes granular, shredded, and tenacious. If red blood corpuscles are eliminated in great numbers they col- lect in the form of a red dise on the yellow to yellowish-brown base, which is composed of leucocytes and coagulation masses. In hemorrhagic stages of the inflammation the milk is pinkish or brownish-red; by sedimentation it separates into a Bordeaux-red or rust-colored precipitate, and a pinkish-red layer of cream over the reddish-gray skim milk. In other cases the milk becomes grayish and watery, and only a few thin conglomerates and fat globules indicate the layer of eream. Cream and sediment are especially rich in cells in all forms of inflammation. Epithelial cells are desquamated into such milk in the form of colostral cells, or entire epithelial bands, and numer- ous polynuclear leucocytes, besides single epithelial cells, into which macrocytes penetrate (albuminophores), erythrocytes, cell debris, fragments of nuclei, as well as Nissen’s globules are found. Besides concrements of the most varied quality, casein and Mastitis. 19 fibrinous flakes appear (Zschokke, de Bruin, Kitt, Sven Wall, Doane, Russell and Hoffman, Ruhm, Ernst, Bahr and others). The taste of milk from affected quarters of the udder is also affected markedly, the milk becoming salty, bitter, and pungent. According to Craandijk in 67% of cases the taste of the milk changes in streptococcic mastitis. From the appearance which the affected quarter manifests, as compared with healthy quarters, from the change in the behay- iour of the animal, from the varying quantity of the secretion against the quantity from healthy quarters or the previous yield of the same quarter, the milker becomes suspicious of the existence of an abnormal condition in the suspected quarter, and the tasting test reveals a salty, bitter taste which assures him of the appear- ance of a change in the activity of the gland. If the udder secre- tion could be examined on the hollow of the hand before being milked into the pail, in order to determine the possible presence of flakes, ete., as should be the duty of the milkers, then the mix- ing of such milx from affected quarters would not occur to the extent that it does at present, as has been proved on numerous occasions. A great deal would be gained if the milk from those quarters which produce a milk so changed that its abnormalities ean be recognized by its appearance or taste could be totally de- stroyed. As a matter of fact milkers can much more readily rec- ognize developing inflammations of the udder (as for instance streptococcic mastitis) from the varying conditions of the udder, or quarter, the quantity of milk, and the behavior of the animal, than the veterinarian can by a single clinical examination. Therefore the method applied in practice consisting of a single clinical examina- tion of the cows producing infant milk at the time of purchase, or every 3 to 4 weeks is not sufficient to determine the presence of ud- der affections. Periodical examinations of all cows producing certi- fied milk, supplemented by tests of the milk obtained at the time of the examination, are necessary when the inspection is to serve its purpose. At the examination in the stable a comprehensive history should be taken from the milkers relative to the general condition of the cows, their action during milking, the condition of the teats and the gland tissue, the inflammatory changes noted, in fact all points which may offer valuable supplements to physical examina- tion. One may learn from questioning that the cow milks very hard from one quarter, that she sometimes refuses to ‘‘give down”? her milk, or that she ‘‘draws up’’ the milk or that recently the cow has shown a tendency to kick during milking. At other times one may hear that the parenchyma contains knobs or lumps or that the teats contain beads or warts, or are ‘‘fleshy,’’ the quantity of milk is diminished, the milk is sometimes hot, ‘‘heated,’’ or that the cow has the ‘‘cold garget’’ without any inflammatory indications of streptococcic infections. The milk is ropy, the 80 Effect of Internal Influences. quarter is ‘‘blind,’’? the milk contains stringy clots and other things. The keeping of milk records and the taking of milk samples at least every four weeks, should be required of all owners of animals which produce milk for city consumption and those fur- nishing it to wholesale milk dealers. , Together with the visible changes in the milk, changes of the value of the chemical and physical properties occur which have been especially studied by Guillebeau and Hess, Schaffer and Bondzynski, E. Seel, Mezger, Fuchs and Jesser and Mai and Rothenfusser. These changes in the contents and properties are therefore especially important since frequently values are obtained which suggest adulteration with water. Irreproachable comparative tests of milk obtained directly from the stable may indicate however that in the specific cases the investigations were being made with abnormal milk. According to Schaffer and Bondzynski’s examinations the milk from cows affected with mastitis showed the following values: Water Solids. Fat Pro- Milk Total % % teid Sugar Ash P50, CI. In non-infectious SEE kl Sno mica 92.83 Celli 0.82 4.01 0.53 0.79 7.35 35.76 Im yellow. galtin jes. 89.34 10.66 1.59 6.00 1.84 0.83 In parenchymatous MASUUbIGe ee rtonemrcers 90.26 9.74 2.16 4.21 1.01 0:97 Otero In comparison with healthy LaF ullll i Eni tha 0. oe 87.75 12.25 3.4 3.5 4.6 0.75 20.0 14.0 The milk sugar content was also considerably diminished; the amount of mineral substances on the other hand was increased. Guillebeau and Hess give the following values in milk from cows with affected udders: Duration of the Disease and Origin Specific Solids. Fat Nitrog- Milk Ash of the Milk Gravity enous Sugar subst. ADVE 0 Eh (Sars tae ee Ce EO ERO Ree Ia te Des 7.45 0.52 6.17 ae 0.85 2 gee tes ay RNS uae ac ees pen te cy cE al 5.15 0.22 4.26 0. 0.82 5 GG NGKiit WACOM 5 gagae. accor 9.80 1.95 2.98 4.06 0.81 7 GOSS Nim fores os utente curd peak ee 1.0314 11.28 2.72 3.50 4.35 0.70 2 GO Rte cones ea ins eepegeyoaehae | ed paver a ie 7.69 1.09 5.74 0. 0.87 2 Sila pets Anitrise Sat detent cattery Renee eaeunice eee pepecccaee 23.58 9.30 8.53 4.68 1.07 1% ‘* from two affected quarters ..... 15.88 4.50 5.37 5.14 0.87 1% ‘* from two affected quarters _..... 9.66 2.09 6.74 2.09 0.85 U POE | NE cya Savoury he OR caw clea smewlayheratie: Med Gena tenet halal erect 0.53 5.13 ote ae 8 ““ from two affected quarters _—....... 15.88 4.50 5.387 5.14 0.87 2 ““ from two affected quarters 1.0430 20.94 0.97 16.65 2.61 0.71 21 See SCN Meal MOR Test CERO ON FOS ON elisals 2.80 7.93 2.04 0.91 In most cases the specific gravity is lower (Seel, Mezger, Fuchs and Jesser) and approaches the normal only towards the end of the disease. In mixed milk from all four quarters the specific gravity is less influenced. The quantity of fat, according to Seel, and in some cases of Mezger, Fuchs and Jesser, is very much reduced. The latter authors emphasize the fluctuation of the fat in sudden jumps. The experience of the official milk control station in Munich also gives similar results, at the beginning of the affection frequently finding abnormally high or again abnormally low fat contents of the milk. Mastitis. SL The amount of milk sugar as a rule is reduced, and rises only with the appearance of recovery. The solids are likewise usually diminished; the fat-free substance is also, and only becomes increased after signs of recovery have been noticed. The amount of proteid coagulable by heat frequently increases enormously, as compared with the contents of casein which diminishes. The ash content on the average is increased. Relative to the composition of the ash the data appear to ke contradictory. Although Seel found in 15 cases out of 18 a diminution of chlorides against an increased quantity of P20; Mezger, Fuchs and Jesser observed an increase of the chlorine content and a diminution of the phosphoric acid, while Steinegger and Allemann found that the amount of P20;, CaO, K20 and MgO diminishes, in general, while the quantity of Cl., NovO and SOs increases. According to Hashimoto the ash of abnormal milk closely approaches the ash of blood serum (0.78%), consisting of 8.9863 K 20; 36.544 Na.O; 7.44 CaO; 1.738 MgO; 17.380 P,0; and 33.627% Cl. The reaction of affected milk is mostly alkaline (Seel, Mezger, Fuchs and Jesser, Hoyberg, Auzinger, Ernst), or more rarely acid (Zschokke, Henkel, Wyssmann and Peter, Ernst). The determination of acidity is recommended by Plaut as a means for the diagnosis of udder affections. Independently from the degree of acidity, the coagulability on the addition of alcohol is frequently considerably increased but not always, and in some cases not con- stantly. (Henkel, Rullmann and Trommsdorff, Auzinger). The refractability of the calcium chloride serum not infrequently suffers con- siderable changes upward and downward. Ripper, Ertel, Mairhofer, Schnorf, Mai and Rothenfusster, Henkel, Mezger, Fuchs and Jesser found considerable changes in this respect and proved that the daily variations in the refraction may be very great in milk of individual quarters, and even in the full milk of an animal. Frequently however the refraction of the calcium chloride serum shows no change when compared with the milk of healthy animals. The same variation obtains in the lowering of the freezing point of milk from affected quarters; the values may be considerably higher than that of healthy milk, or on the other hand they may be lower. More frequently a high value is observed (Schorf, Quiraud and Laserre, Crispo, Bertozzi, Pins). According to Schnorf the elec- trical conductivity is always increased, never normal or lower. According to Bonnema the increase of chlorides results in an increase of the electrical conductivity. A change in the contents of original ferments appears very early during the affection, together with an increase of cellular elements, especially leucocytes (Zschokke, Bergey, Trommsdorff and Rullmann), and fibrinous flakes (Doane, Russell and Hoffmann). According to Koning the increase of the catalase content in freshly obtained milk is an indication of the affection of the ud- der, provided the colostral period has passed. The publications of Spindlers and Rullmann (who were enabled to obtain asepti- eally milked samples with which to work) and the author’s obser- vations confirm Koning’s findings. The author observed that in slight, local affections of a chronic nature, without febrile mani- festations, the content of catalase usually runs parallel with the cell content, and it rises when there is an especially marked throwing off of epithelia (presence of typical colostral cells). The faculty of splitting up added starch solution likewise in- creases in milk from affected udders ag compared with that from healthy udders. There are no observations relative to the quanti- tative effects of peroxydase. According to Weichel the peroxy- dase content of affected milk from an artifically affected goat dis- appeared, whereas the healthy milk gave the guaiac reaction. — 8? Effect of Tntemial Influences, The reaction again appeared when the secretion became of a milk- like consistency. Affected milk behaves in various ways on the application of formalin-methylene blue solution; frequently a very rapid decol- — oration of Schardinger’s reagent may be observed (Rullmann, Sas- senhagen, Rievel). Sometimes in typically changed samples the reduction does not take place (author’s observation). As the above-mentioned enzymes (not amylase), at least in part may appear to be brought on by bacterial action, their abnor- mal presence in milk has a diagnostic importance only in freshly milked samples. The ease is different with the complement con- tent. As indicated in the chapter on antigens, blood constituents pass directly into the milk during periods of physiological and pathological irritations. Therefore in mastitis, as proved by Bauer and Sassenhagen, complements are demonstrable in the milk. This, according to Sassenhagen, is possible even in affec- tions in which the Trommsdorff value of the centrifugalized cells per 1000 parts of milk is still remarkably shght. The alkaline reaction of affected milk, the altered proportions of mineral salts, at times the passing into the milk of bloody parti- eles, and the diminution of casein, reduce the coagulability of the milk towards added rennet. Affected milk therefore generally utilizes a considerably larger quantity of rennet than normal milk before it becomes coagulated (Schern). The spontaneous coagulation of affected milk also appears to be considerably delayed. Infectious Agents of Mastitis. Noecard and Mollereau, Kitt, Lucet, Bang, Guillebeau and Hess, Zschokke, Jensen, Streit, Glage and Sven Wall have offered sufficient information regarding the infectious agents of the dif- ferent forms of mastitis. Most cases of mastitis are produced by streptococci; they consist of chronic inflammations of one or more quarters of the ud- der. The disease is of relatively small influence on the general condition of the animal. Bacilli of the coli-aerogenes-paratyphus-paracolon groups pro- duce highly acute, parenchymatous lesions. The general condition is severely influenced thr ough infections by “bacteria of the paratyphus-B group. Locally a gangrenous, septic mastitis de- velops with this infection, and the milk is markedly ichorous, while in colon infections the secretion is of a serum-like character (Weichel). A third form of inflammation of the udder, also of a chronic nature, is produced by a representative of the eroup of the Bacillus pyogenes, Sven Wall’s pyobacillosis of the udder. The Bacillus pyogenes colonizes with a special predilection in the pres- Streptococcie Mastitis. 83 ence of streptococci or staphylococci, and in these mixed infections causes severe necrotic inflammations of the udder, and may con- tinue to produce chronic mastitis in the affected udder tissue after the disappearance of the other bacteria. Other forms of mastitis are produeed by tuberculosis and actinomycosis, and they usually result through emboli of the in- fective agents. They may be of a traumatic origin (actinomycosis) mduced by irritation with particles of straw, or barley beards. Furthermore all possible infective agents, as for instance the Bacillus necrophorus, may be found in inflammations of the udder, either independently or as mixed infections. Only the more important infections of the parenchyma will be described here. Streptococcic Mastitis. By far the most widely spread type is the streptocoecic mas- tisis, described by Sven Wall as streptomycosis of the udder. The works of Bergey, Craandijk, Trommsdorff and Rullmann, Kkunze, Russell and Hoffmann, Savage, Riihm, and Ernst give gen- eral information on this condition. The disease is either sporadic or epizootic among the animals of a stable according to the stable conditions. The disease may attain an especially wide distribu- tion when the secretion of the affected quarter is milked upon the floor or into the bedding, and the milkers fail to wash their hands, both bad practices which, it is to be regretted, are quite common. Zschokke, Jensen, Bang, and Sven Wall proved experi- mentally that bacteria injected into the cistern penetrate even into the farthest alveoli in from 2 to 24 hours. By inoculating with strains of streptococci of different ori- gin varying reactions may be produced in the udder (Bang: Strep- tococcr equi and Streptococci agalactie; Gminder: streptococci of the stable air and of infectious vaginal catarrh). The manifesta- tions also vary after the injection of individual strains into the same animals, and from injections of the same strain into various animals. In other words the course of the disease varies in ac- cordance with the virulence of the organism, the resistance of the body, and the extent of the local invasion which again is influenced by the lactation period. According to de Bruin fresh milking animals more frequently become affected with the acute form having inflammatory manifestations, while in old milking animals the disease confines itself mostly to the altered appearance ot the secretion. The result of the disease is that sooner or later the affected part of the gland becomes destroyed. Sometimes the streptococci remain for weeks in the folds of the mucous membrane of the cistern without infecting the par- enchyma; in other cases again the entire quarter quickly becomes affected. Unfortunately the disease does not often subside even 4 Effect of Internal Influences. through the physiologically dry period, and the affection re-ap- pears immediately after parturition. The destruction of all streptococci involves a difficult task for the entire body. The dissolution of the streptococci progresses only very slowly even in actively or passively immunized animals. Living streptococci may be demonstrated in the abdominal cavity of test animals, many hours after an intra-peritoneal injection. Not infrequently a delayed death appears in apparently recovered animals (v. Lingelsheim). The long streptococci appear to rep- resent specially adapted forms which have great tenacity. Never- theless at times recovery takes place. According to Zschokke the relation between recovered and unrecovered cases is as 7:5. According to the experience of the author in practice, infectious mastitis is not curable, or only with the greatest difficulty, and if so, always with a loss of productiveness, which even remains after the physiologically dry period. The chronic irritation causes a change in the connective tissue structure of the parenchyma of the udder so that the usual development of the gland during pregnancy eannot take place. The principal aim in treatment therefore should be prompt drying of the suspected udder, in order to make possible the most rapid and most complete recovery, which, ac- cording to Zsehokke may be expected only when the quarter has been allowed to remain dry for a long time. This is also necessary in order to prevent a spread of the disease, which is to be feared since the hands of the milkers and milking upon the straw may transmit the infective agent to other quarters. Care should be taken therefore to keep the milk from the healthy quarters of the udder separate from the secretion of the affected quarter. As long as the most primitive requirements of clean milk production on the part of the milkers are so carelessly neglected, which unfortunately has been the case up to the present, the im- mediate drying of the affected quarter offers the only means of preventing the further spread of the disease. If, however, there is assurance that the affected animal or the affected quarter, respectively, is individually milked, and the milkers follow instructions, an attempt may be made by special frequent milking (into a jar) to produce a hyperemia of the udder. With this method success can only be expected in the early stages. The extent of the spread of the disease may become obvious by the findings after examination of individual herds. In such cases it is necessary to milk each cow, or still better each quarter, separately. The results vary, depending on the technique of the examination. The lowest number of affections is obtained when only a clinical examination is made. This therefore does not suffice in order to eradicate the disease effectively, or to single out the affected animals. The data of the different authors vary relative to its occurrence. The following figures are given which were obtained by systematic examinations of entire herds. Streptocoecic Mastitis. 85 Out of 260 animals Trommsdorff found 15.6% affected, Ruhm 31.25% out of 16 animals, Russell and Hoffmann found in 188 sam- ples 50% with ‘‘streptococci.’’ Savage found similar values (957%). The author examined from April 1, 1907, to November, 1908, 1697 samples of milk from individual cows, and found in 348 sam- ples the typical signs of streptococcic mastitis. In 1908 and in the following years he has demonstrated: ~ 1908. No. of animals, 1695. Streptococcic cases..... 308 1909. No. of animals, 738. Streptococcic cases..... 301 1910. No. of animals, 597. Streptococcic cases..... 203 1911. No. of animals, 876. Streptococcic cases..... 29 Therefore 20.6; 20.9; 40.6; 34 and 31.8%, respectively, of the animals were found to be affected with streptococcic infections of the udder. If the milk of the individual quarters of the affected udder is - examined various stages of the affection in the different parts of the udder may frequently be found. Out of 528 quarters of animals with affected udders 276, or 52.2%, showed lesions in individual quarters. 39.2% of the cows had the disease in one quar- ter, 25.9% showed it in two quarters, 18.5% in three quarters, and 16.2% in all four quarters. According to Zschokke ont of 662 affected quarters 193 occurred in one quarter of the animal, 211 in two, 109 in three, and 149 in all four quarters. The contamination of market milk with the secretions from animals with udder affections is relatively high. In spite of the fact that proof of the mixing of milk from affected udders with market milk is possible only in very pro- nounced cases (typical streptocoecic chains with characteristics of animal origin), nevertheless the following results, obtained in examinations, demonstrated conclusively that the secretion from quarters affected with streptococcic mastitis had been added to the whole milk: 1908, in 352 out of 1578 samples=22% 1909, in 501 out of 1629 samples—40.5% 1910, in 243 out of 1211 samples=20% 1911, in 432 out of 1273 samples=33.9% The hygienic importance of the affection to the consumers of milk may be illustrated from the following data. I. Holst, in 1894, had the opportunity of examining in Chris- tiania four series of affections of acute gastro-intestinal catarrh. I. Four grown persons and four children out of three families in the same street became affected four hours after the drinking of milk which originated upon one farm. Those persons who drank no milk or only that which had been boiled were spared mh ane cee buon of a child who became affected, although only slightly, after drinking oiled milk. 86 Effect of Internal Influences. The appearance of the milk showed nothing abnormal, but it coagulated on boiling and showed a tremendous number of bacteria, especially streptococci, which could not be distinguished from the Streptococcus pyogenes. The veterinary examination confirmed the suspicion that a pus-containing secre- tion was being yielded by one cow. The milk from the cow with mastitis on the day in question was added to the whole milk through the neglect of a newly hired attendant. 2. Several hours after the drinking of raw milk five persons, and as found later other cases also became affected with acute gastro-intestinal catarrh. In this ease a milk dealer was implicated, and it was found on inquiry that the milk econ- tained secretion from a cow affected with streptococcie mastitis. 3. According to the observations of Johannesen two persons (mother and child) became sick after the drinking of milk. The milk was thin, flaky, and contained pus-like lumps. In the herd from which this milk originated two cows were found to be affected with streptococcie mastitis. 4. After the drinking of freshly drawn raw milk four children of the same family became affected with acute gastro-intestinal catarrh. The milk appeared ap- parently normal, but contained large quantities of streptococci. It originated in a stable from which on the day in question a cow was sold on account of mastitis. The milk from this cow appeared to have been mixed with the whole milk due to the neglect of a new milker (the regular one being sick). The affections which occurred in Stockholm with symptoms of fever, dullness, attacks of fainting, nausea, vomiting, diarrhea and cramps in the calf of the leg (nine families being involved), cannot according to the obtainable reports, be de- clared to be streptococcie infections. The milk, through the drinking of which the cases could be traced, originated from a dairy of 14 cows, among which one cow had mas- titis. It is possible that in this case an infection with bacteria of the paratyphus group, which plays an important part in the development of acute mastitis, was con- cerned. Further contributions to the easuisties of ‘‘milk poisoning’’ were published by Jakobsen and Weigmann and Gruber. II. In 1905, Jakobsen observed symptoms in several persons which he traced to the drinking of milk from one stable. The symptoms were diarrhea, vomiting an fever. Out of 17 persons, 10 who drank the milk became affected, while 7 who did not take any remained well. On May 30, 1905, other persons became affected. The examination of the 32 cows of the dairy showed a streptococcie mastitis in one animal. The cow was slaughtered and no further cases were reported. TIT. Edwards and Severn described an epidemic of follicular tonsilitis which de- veloped from the drinking of milk. They found in the exudate of the throat, and in the milk, in addition to other, bacteria pyogenic streptococci which as shown by the in- vestigation were also contained in the secretion of a cow affected with mastitis. [In various cities of the United States epidemics of sore throat with swelling of the cervical lymph glands, colic, diarrhea and fever lasting several days have occurred which were traced to the use of milk from cows affected with streptococcic mastitis. Such milk when examined was found to contain pus and streptococci in ereat abundance.—Trans. | TV. Lameris and Harreveld observed an outbreak of diarrhea among ‘he inmates of a hospital after the drinking of boiled milk, which in part was obtained from cows affected from streptococcic mastitis. Whether the authors of the last cases are correct in their view that very likely a heat-resisting toxin brought on the disease, or whether the streptococci might remain alive in the milk foam or in the formed membrane, ete., as suspected by Jensen, it becomes evident that boiling does not carry with it an assurance that the danger from streptococcic milk is eliminated. If Jensen’s sus- picion is correct a proof would be offered that even the smallest RN Serine ir te ee Hrnst, Milk Hygiene. Table LI, f the udder, ions oO ffeet In varlous a Appearance of milk Streptocoecic Mastitis. 87 quantities of mastitis streptococci are sufficient for the production of severe intestinal affections. V. On December 17, 1907, a sample of boiled milk was brought to the official milk control station of Munich; about a half hour after the drinking of this milk the man who delivered the milk, and his family, as well as a neighboring family using milk of the same origin, became sick.’ The milk contained 1.5:1000 streptococcice pus. It orig- inated from a large dairy. Three producers and one distributor were suspected. In tracing down the cause of the trouble two producers were found whose herds contained six animals with affected udders, their milk being mixed with the whole milk. The affection was marked by chills, diarrhea, headaches, and lasted not quite an entire day. The milk constituted the only common food partaken by all, and there- fore could be considered, although not with absolute certainty, as the probable cause. From the examples cited it may be seen that the drinking of milk which contains the secretion of streptococcic infected udders is capable, under certain conditions, of producing injurious effects upon the health of human beings. Considering the fre- quency of the disease, and the numerous cases where the prohi- bition of milking affected udders into the whole milk is disre- garded, it is to be wondered at that affections which could be traced to the drinking of such milk are not observed with greater frequency. This may be due to the fact that the secretion of affected quarters is usually very greatly diluted with the milk of healthy quarters, showing that the harmful actions are not necessarily induced by the predomination of the injurious material, and fur- ther it may also be due to the fact that the milk is mostly used after being boiled (Trommsdorff, Jensen). That the boiling of the milk is not always sufficient to destroy the injurious properties may be seen from the cases of Holst and Lameris and van Har- reveld; the milk of course is marketed in a raw state, and must therefore be judged in the condition in which it is sold. The factors which induce the harmfulness of the milk from streptococcic animals are not known. Whether the injurious factors are due to the toxin produced by the streptococci of mastitis, or to the products of the disease, as for instance pus (Jensen), or to streptococci which are pathogenic to man as such, cannot at the present time be definitely determined. This, how- ever, is of little importance from a practical standpoint. Some authors, such as Petruschky and Kriebel, consider that infected cows are the sources of milk streptococci, and that these are the principal cause of the summer mortality of children. Seiffert considers the streptococci originating from affected udders as more dangerous than the saprophytic streptococci which contam- inate the milk as a result of unclean milking. This view was also expressed by the author in May, 1908, and was confirmed by Trommsdorff. Neither studies nor animal experiments have succeeded up to the present time in proving the harmfulness of the streptococci by themselves, or the relationship of the mastitis streptococci to human pathogenic strains of streptococci, the animal experiments 8s Effeet of Internal Influences. offering only a relative conclusion on the susceptibility of the respective species of animals. The differentiation of the mastitis streptococci from other milk streptococci is however, absolutely necessary for milk control since only in the presence of typical mastitis streptococci can the milk dealers be held responsible, and be obliged to prevent the contamination. Escherich and Holst found streptococci in almost every sample of milk, and Hellens repeatedly isolated them from milk. In 1840 in samples of market milk from Munich and vicinity the author succeeded in isolating streptococci either by eulti- vation or recognizing them by bacteriological examination in 100% of the cases. Other investigators confirmed a positive finding in a strikingly high percentage. Beck—Market milk of Berlin.................0-00:. 2 rage tee cae 62 % Savace—— lt samplesoL manketrmillkes ee cesses eee er nate ee 100 % iOvsamplesotamanketemille ras, fates a anh pena Oa ke ieee meget 100 % Kiarser=—Market milk of \Gra rive ce se okie aed ee ae et eee 76.6% Briining—28 samples of Leipsic market milk...................+.0- 93 % Hasten-——USOrsamiples oe cosets ce cardia hee, < si Sytecey Sole ee een Mm Eastles—185 samples from all parts of England................... 75 The simplest proof of the constant occurrence of streptococci in market milk is the usual acid fermentation of cow milk induced by streptococci. A method for distinguishing these frequently observed strep- toecoeci from mastitis streptococci has not yet been discovered, either through the fermentation of various kinds of sugars by the streptococci, or through the investigations of creatinin forma- tions, hemolytic action, acid formation or their actions in the pres- ence of various temperatures of cultivation. It should be borne in mind that the behavior of the various strains of mastitis strep- tocoeci has been described in such a variety of ways, that either the presence of remarkably numerous strains or a strong instability of characteristics, or confusion with saprophytic forms, must be accepted. The formation of acid by the streptococci is sometimes de- seribed as strong (Zschokke, Nenski, Groning, Kaiser, Heinemann, Miller, Koning), at other times it appears insignificant (Sven Wall, Rullmann). Lohnie classes the streptococci of mastitis with the group of lactic acid streptococci, especially with the group of Streptococci guntheri, with close relationship to the group of Streptococci rosenbach, having the following characteristics : ‘“Form of the cells variable; capsule formation is frequent and appears to be as- sociated in certain forms with the presence of sugar in the nutritive media. Spores are not formed; the bacteria are Gram-positive; the intensity of the growth has no sig- nificance. Coagulation of the milk results, in these varieties, either through acid formation or through a rennet-like ferment; gas formation is rare; the pathogenicity varies remarkably. ’’ Miiller in his work on comparative examinations of lactic acid bacteria (Typ. giin- theri, etc.) presents the following: 1. ‘‘The strains studied manifest marked differences either in their cultural or morphological characteristics with the exception of the strain causing ‘‘sour brood’* among honey hees.’’ 2. ‘“The action on carbohydrates is practically uniform.’’ —Streptoccecie Mastitis. 89 3. ‘‘Influencing individual strains relative to their acid formation in the sense of increasing or decreasing it, is possible. The characteristics which the freshly isolated strains possess are more or less permanent.’’ 4, ‘‘There exists a relation between the group of Streptococcus giintheri and the Streptococcus agalactiae since their capability of forming acid is about the same.’’ 5. “The oft recurring confusion of the two may be explained by certain similar forms of growth which both possess.’’ 6. ‘‘The supposition that the pathogenic streptococci represents lactic acid bac- teria of the Typ. giintheri which have adapted themselves to parasitic conditions, is sub- stantiated by the findings, since it was possible in the various strains of streptococci to produce transition forms, which correspond to the Typ. gitintheri.’’ Therefore from these few examples it may be seen that it is inpossible to separate the streptococcus of infectious mastitis from the group of the lactic acid streptococci. Nevertheless it would be a great error to identify the ordinary lactic acid Fig. 17. streptococci with patho- genic streptococci of man and animals. If the fact is taken into consideration that some streptococci, as for instance that of Kefir, the streptococci of sour milk, and others, have a fa- vorable influence on the nutrition of man, the ne- eessity of their strict identification for control- lng the milk supply is apparent. Although it is not possible to absolutely dif- ferentiate one strain by cultural and_ biological Onno Sediment of milk, one day old, from an udder affected characteristics, from a with streptococcic Ga (a) ebreptocores. of in- S : fectious mastitis, (b) subsequently developed strep- culture strain of differ- tococci; 1, 2, 3 and 4, cells from the udder. ent origin, nevertheless there are certain morphological characteristics of the streptococci in the smears made from sediments, which are sufficiently constant to absolutely warrant the definite assertion that the streptococci in certain positive cases originated in an infected organ, and were not incidentally leading a saprophytic existence in the milk. It has been known for a long time that parasitic bacteria in the animal body, under the influence of the animal’s protective strength, attain certain peculiarities of form which they lose under ordinary cultural conditions (under certain conditions it is possible to cultivate capsulated anthrax bacilli). Reference is made to the capsule of anthrax bacilli and to the formation of botryomy- eotic clumps by streptococcic forms. Consideration of the question whether such changes of form in bacteria are developed as protec- 90 Effect of Internal Influenees. tive agents against the immunizing powers of the body, would re- quire too lengthy a discussion. The fact should suffice that strep- tocoeci originating from affected udders almost invariably show signs of such transformation. It is not intended to assert that a steptococeus in milk which does not possess these form peculiari- ties is not a streptococcus of mastitis, or that it does not originate from the udder, and that under abnormal conditions (for instance cultivation at 37 deg. in raw milk or in serum) the streptococei which are present could not undergo changes of form which under certain conditions simulate the forme of ‘‘animal’’ streptococci ; but for normal conditions of milk inspection the morphological characteristics of animal streptococci offer certain definite appear- ances of recognition which have always been proved by control tests made in the respective stables. These characteristics are the following: The streptococcus takes on a diplococcus- like separation, the cocci apparently press each other, become disc shaped, and in profile ap- pear like a dash. They stand at right angles to the length of the chain (compare with equine distemper streptococci according to Rabe.) " ihe isnt) NS rf x Z f tormed only at the beginning, are of interest. KA oe 8 IA. Pa Nv - Against the practical utilization of these 4 >> ~ > a observations, namely the conclusion that the ex- ~ BN AY Sates we Pf) elusive presence of dextro-rotary lactie acid is SN e “ar =} dependent on the specially clean procurance of Pr Tp vy oy 2 (A the milk, are the investigations of Pere and ser Av 4 ¢ “| Harden, who claim that the nature of the ‘“ ly uv, acid formed depends not only on the producer pid but also in the case of the same producer on 2 =~ eS L as ~8 H the character of experimental procedure; thus e377) 0% } Rsk i for instance one and the same strain of Bac- — X/ > terium coli produced lactic acid showing opti- ly CONs,! 4 e oe, 41 cally different properties when cultivated under | hor wet; AV orn different conditions, aérobically or anaérobi- 7 cally, ete. ve PSEA SH The Bacillus acidt lactict = Gye ine MONEE ¥| (Hueppe) group also does not rep- ‘2 (iad RLS resent constantly uniform species, he LG 4 F th ARG of but it is a collective name which . - f (F] RS Te, 1 ¢ 5 = A “ eis “a sid unites all bacteria with especially Representatives of the _ coli-aerogenes strong acid forming properties that group, from a quitnre. 1 x 800. (Bee Jean towards the colon amdleage: clally to the aerogenes species. The Bacterium acidi lactici Hueppe and the Bacillus pneumonie Friedlander are similar to the coli-aérogenes species. They are plump, mostly Gram-negative, from cocci to short rods in appearance, forming individually longer rods and short thread-like filaments; they grow luxuriantly, forming moist or almost dry indented colonies with a slimy or jelly-like consistence. In dextrose media usually a strong acid formation takes place. On potatoes the growth is either luxuriant with gas bubbles, or brownish and thin, or transparent. The odor varies, being either disagreeable or pleasant, or at times even odorless. From this description it may be seen that a great number of bacteria are united in this group which are elassed by Lohnis as follows: 1. Type of the Bacillus acidi lactici Hueppe. Gas formation with milk coagulation. To these belong the Bacillus aérogenes, Bacillus ‘‘a’’ Guillebeau, Bacillus ‘‘b’’? Freudenreich, Bacillus laevolacticus, Bacillus acidi lactici Gortenfeld, also the lactic acid bacilli of Fokker and others which possess differing characteristics, as for instance the formation of esterlike odors, cheesy odors, ete. 2. Milk coagulation without gas formation. Bacillus limbatum (acidi lactici) Marpmann, without special tendency to deep growth. Bacillus acidi aromaticus, Bacillus granulosum, crenatum, spirans and ramificans (Weiss) and others. 3. Gas formation without coagulation of milk, producing white, circumscribed, hemispherical colonies, as for instance the Bacillus pneumoniae Friedlander. 4, Neither gas formation nor coagulation. Cheese Bacteria. 167 5. Neither gas formation nor coagulation, but slime formation is present, for instance the Bacillus capsulatus, Bacillus viscosus, Bacillus capsulatus mucosus, Bacillus lactis pituitosi, Bacterwwm ozaena. 6. The tendril-shaped colony forming Bacillus aerogenes capsulatus. 7. Without gas formation, but with liquefaction, for instance the Pneumobacillus liquefaciens bovis. A decisive separation of these types cannot be strictly ac- complished anywhere in the entire group. Hach type has indi- vidual or several representatives which show transitory tendencies towards one or the other group, and the entire group is closely re- lated to the colon aérogenes group, but in the latter, there are no such pronounced lactic acid formations. The colon group is motile, the aérogenes group non-motile. While the colon bacilli form indol and split up proteids, these properties are absent in the aerogenes eroup. Milk is coagulated with gas and acid formation, in which the casein usually remains on the surface of the pressed-out serum in the form of a spongy coagulum. The milk receives at the same time an unpleasant, slightly offensive odor, and a salty, bitter taste. Some varieties change the milk in this manner without the special changes being perceptible. The several groups adapt themselves very rapidly to their surrounding conditions, for instance to the cultivation on cabbage or turnip media, and when transferred to milk they impart to these the well-known changes of taste. Both bacteria are found in the intestines of sucklings (Escherich). It is an important fact that most bacteria of this group are destroyed in a short time at 65 dee. C., so that their occurrence in pasteurized milk (in bottle pasteurization) may be an indication that the heating to which the milk has been subjected was insufficient. According to De Jong and Graaf some varieties of the colon group resist heating to 70 deg. C. for a short time. The slender ‘‘cheese bacteria’’ of the third group of the lactic acid producers are again divided into: 1. Those coagulating milk with gas formation, for instance Bacterium casei (Freudenreich), Bacillus caucasicus of Kefir (Freudenreich) ; 2. Those coagulating milk but with no gas formation; 3. Those producing gas but no coagulation; 4. Those showing neither of these characteristics; 5. Those producing slime; 6. Those growing in tendril-shaped colonies. The bacteria of this third group are almost invariably non- motile, and sporeless, mostly without capsules. They are Gram- positive. The fermentation of sugar varies. In milk they mostly form levo-rotary lactic acid, while the other two varieties are rarely produced. Some peptonize proteids; their growth is favored more by aerobic than by anaérobic conditions. 168 Bacteria in Market Milk. The bacteria do not grow well in milk but they are found in cheese, in the oriental varieties of sour milk and in sour food. These bacteria are of only slight importance in the ordinary lac- tic acid fermentation. They prefer higher temperatures and pro- duce fermentation only in the absence of oxygen, although their growth is prolifie even in the presence of oxygen. As representatives of this group the Bacillus panis fermentati occurring on sour bread should be mentioned, and the Bacillus delbriicki: found on sour food. Some representatives of these ‘‘cheese bacteria’’ are capable at high temperature (40-50 deg. C.) of producing and withstanding large quantities of lactic acid, up to 1.5%, and even to 2 to 2.5%. Lohnis classifies the staphylococci as the fourth most widely distributed bacterial group of the lactic acid producers, but on ae- count of their peptonizing characteristics they might better be considered with the casease bacteria of Weigmann. Their proper- ties have already been described during the discussion of bacteria of the first decomposing phase. The staphylocoeci may also be separated into: (a) Those coagulating milk and liquefying gelatin. (b) Those which only liquefy gelatin. (c) Those which only coagulate milk. (d) Those which posses neither of these properties, nor form slime, produce gas, nor form tendrils. The species mentioned by no means exhaust the number of species and groups which are capable of producing lactic acid. Thus the anthrax bacillus splits up sugar and starch into lactic acid, and also forms acetic acid (Napias), and formic acid (Iwanoff). Feinberg demonstrated for the diphtheria bacillus the capability of splitting up milk sugar with the formation of alcohol, aldehyde and volatile as well as non-volatile acids. The bacillus of malignant edema, according to Kerry and Frankel, in the anaérobic fermentation of grape sugar, produces ethyl alcohol, formie acid, butyrie acid and lactie acid; cholera vibrios and related organisms form lactic acid; for instance the vibrio of Asiatic cholera, the Vibrio proteus (Finkler and Prior), Vibrio massauah, vibrio danubicus and others form levo-rotary lactic acid, the vibrio of Deneke forms dextro-rotary and Vibrio berolinensis produces an inactive lactie acid. The formation of these lactic acids, however, does not depend on the bacillus alone. The Oidium lactis, a milk mould, and others, are also capable of producing lactic acid from milk sugar. Some of the lactic acid forming varieties are rare in milk, others may accustom themselves to milk so rapidly that they form the typical acidifying flora, the presence of which under certain conditions may be desirable since by their multiplication the vegetation of the harmful peptonizing bacteria and of the producers of butyric acid is inhibited. With this we leave the most important varieties of bacteria which are responsible for the normal spoiling of milk, and will briefly discuss those varieties of microbes belonging to the bacte- riology of milk and milk production which always occur in market milk. Milk also invariably contains butyric acid bacilli. Their pre- dominance is inhibited by the lactic acid fermentation. Butyrie Acid Baeilli. 169 The specific butyric acid bacilli are obligatory anaérobic or facultatively anaérobic, that is they thrive best in the absence of oxygen; there are, however, aerobic bacteria which are capable of forming butyric acid, for instance several of the above-mentioned peptonizing varieties, the hay and potato bacilli, which without specially attacking the milk sugar, form butyric acid from the products of the split proteids. The individual varieties show varying properties toward the different kinds of sugars, as well as toward the formed by-products, as butyl alcohol, isobutyl alcohol, formic acid, acetic acid, propionic acid, valerianie acid, carbonic acid, hydrogen, ete. The obligatory butyric acid producers are rods, chains or threads, with either a plump or a slender form; they possess oval or roundish polar or central spores. The bacteria Blackleg bacilli. 1 * 1200. (After Friedberger & Frohner.) frequently form so-called clostridium forms, and especially in starch-containing media they take up granulose; therefore certain parts of their body or even the entire bacillus may be stained blue with iodide of potassium. The representatives of this group are known to pathologists as producers of blackleg, gaseous phlegmons, malignant edema, bradsot, botulism, and tetanus. These bacilli at times are capable of energetically forming butyric acid, and at other times less in- tensively; at the same time peptonizing ferments (tryptic) are formed, which become active in the absence of acid. Generally motile and non-motile forms of butyric acid bacilli are distinguished in milk. The latter form, of the granular Bacillus saccharobutyricus is considered by Grasberger and Schattenfroh as a developing form of the motile, spore-forming variety which takes up granulose, forms toxins, and attacks lactic acid. According to their properties they may be divided into those which form butyric acid principally from certain carbohydrates, 170 Bacteria in Market Milk. as for instance the blackleg bacillus, the non-motile butyric acid bacillus (Grasberger and Schattenfr oh), and the bacillus of gaseous phlegmons (Frankel). The others are producers of putrefaction and split up the proteids inte forms from which volatile fatty acids develop. Obligatory fat-splitting bacteria may also, although less fre- quently, be found in milk, as for instance the Bactridium lipolyti- cum (Huss), through the growth of which the milk acquires a-rancid taste. The Bacillus fluoresc ens, Bacillus prodigiosus and others, for instance certain mould fungi, may also produce fat-splitting enzymes. Actinomyces form the transition organisms which lead from bacilli to higher fungi. These fungi form long threads with true branchings. Widely distributed on grasses and especially grain, as well as in the soil, they are of course also contained in manure and litter, and may occur in milk and milk products, butter or cheese, and multiply therein. As is the case with all milk bacteria, among the actinomyces there may occur forms which under certain conditions such as wound infection, produce diseases (chronie suppurations). Some varieties of bacteria classified by Léhnis as lacto-bacilli, as for instance a microbe isolated by Chatterjee from ‘‘Dadhi,’’ (Indian sour milk) Streptothrix dadhi and several bacteria which were found in Mazun, Yoghurt and in the Montenegrin ‘‘Grusa- vina’’ and ‘‘Kysla varenika,’’ appear from their morphological properties, to belong to the streptothrix (actinomyces). Finally it will be advisable to discuss the higher fungi, yeasts and moulds which occur in milk. They cause a slight aleoholie fer- mentation of the milk; not all varieties however attack the milk sugar, although a great number of the most varied fungi and yeast are found in milk, for instance penicilia, mucors, aspergilli. By far the most frequent fungus in milk is the Oidiwin lactis, under which name are collected all ‘mycelial forms, whose radiating mycelia carry hyphe, that break up into small, rectangular, ee drical members, the so-called oidia, which in proper media agel grow out into a mycelium. The erowth of the oidium variate gives the surface of the cream layer a yellowish-white, velvety, fre- quently wrinkled appearance, which later may take up a glassy transparent appearance. Oidium lactis causes fermentation in sugar-containing media, and develops carbonic acid and a slight amount of alcohol. A pleasant aroma results from cultures in dextrose but in the split- ting up of saccharose, lactose and maltose, an intensive cheesy odor develops. Besides sugar, proteids if present are split up. Therefore in the zones of growth of the oidium varieties a pepton- ization is manifested in the milk. Lactic acid is also produced and later again disappears. Besides the oidia there may also be found the closely related Buttermilk. aval moniliar varieties which at times grow like the oidia with a typical mycelium, at other times it is a sporulating fungus (Mon. varia- bilis; candicans, etc.) ; also varieties of mycoderma, which always multiply in a longitudinal direction, by the protrusion of daughter cells which continuously bud out new daughter cells and these con- tinue to grow in the already established direction. In the preparation of certain fermented forms of milk which are frequently desired in certain sour milk preparations, the sporu- lating fungi which multiply in all directions of space through sporulations are of importance. Through their activity, that is through the formed enzymes, the milk sugar is split up into dextrose and D-galactose, and ulti- mately the dextrose is split up into alcohol and carbonic acid. Milk may contain saccharomyces varieties, which form endospores and torula varieties, whose daughter cells no longer separate in all directions but arranging themselves into rows form mostly spheri- eal shaped or sausage-shaped buds, and have no endospores. Milk Preparations, Buttermilk, Etc., Produced By Special Fermentation. Many varieties of foreign buttermilk or sour milk have recent- ly become known in this country. Especial dietetic value is attri- buted to them; as to whether they possess advantages over our own buttermilk or not is not yet known. The author believes that our native buttermilk possesses the same advantages provided it is prepared with the same care as the buttermilk known as Yoghurt, Mazun, Leben-raib, Gioddu (Sardinia), ete., besides many of the foreign milk prepar rations which are mar keted under various names frequently eontain nothing more than native varieties of our lactic acid streptococci and certain cheese bacteria. Yoghurt is the buttermilk of Bulgaria. It is prepared by adding to the milk the ferment maya after the milk has been boiled down to half of its volume, and cooled to about 50 dee. C. The mass is then kept at 40-50 des. and after 10-14 hours the Yoghurt is finished. The necessary fer mentation temperature is obtained through cooking boxes, or covering the hot vessels with non-con- ducting material (woolens). Weigmann in his ‘‘Mycology of Milk’’ ‘quotes the verbal information. of Kostoff from which it may be seen that the concentration of the boiled milk is not always ear- ried out in Bulgaria, but a ferment (Maya, in Bulgarian Podkwas- sa) 1s stirred up with a small amount of boiled milk, which is added to the milk and kept at 45-48 deo. C. Ifa sufficient amount of fer- ment is added the Yoghurt is finished in from 314-4 hours. It is cooled for 1-2 hours, and may then be consumed. According to information obtained by the author there is an- other method of preparation in Bulgaria which is carried out by the dairymen, and produces a primary Yoghurt. According to the description of Marcoff, to whose kindness I am indebted for this 72 Milk Preparations. information, the dairymen take a widely grown herb (name was unknown to Mareoff), which they erush up in small linen sacks. A small quantity of the juice is then squeezed out and added to the raw milk, whereupon without further treatment the coagulation of the milk takes place within a few hours. From this preparation the Yoghurt then may be prepared. According to this description the primary juice action may be attributed to a vegetable rennet. With the plant juice other bacteria also enter into the milk, the product of which is represent- ed by their elective cultivation. As effective bacteria in the production of Bulgarian butter- milk are considered: 1. A lactic acid long rod, which belongs to the acidophilic bacilli of the intestinal tract: the Bacillus bulgari- cus. This is the aroma producer of Yoghurt. The Yoghurt also contains streptocoeci of lactic acid; yeasts are not desirable (see Table IV). The same conditions exist in the Armenian Mazun, a very aromatic preparation of buttermilk, which is prepared from boiled eow milk, buffalo, sheep or goat milk. Ditiggeli demonstrated that satisfactory Mazun (Tartaric Katych) contains principally three varieties of microbes, a streptococcus, a long rod-shaped lactic acid bacterium, and yeasts, the activity of which produces the aromatic bodies, besides a slight amount of aleohol and carbonic acid. : Leben-raib, according to Rist and Khoury contains five micro- organisms, among them being two varieties of yeast and two lactic acid producers. The buttermilk is prepared in a similar way to Kefir, by using cow, buffalo or goat milk. Kefir has been used for a much longer time and therefore is more generally known. It contains alcohol and is very rich in ear- bonie acid; it has a pleasant, slightly acid odor and taste. It con- tains the milk proteins split up to some extent (Hueppe) in ad- dition to aleohol and carbonic acid and a slight amount of glycerin, succinic acid, butyric acid and acetic acid. Kefir is best prepared from skimmed milk, since in full milk, cream clumps may readily result and the Kefir thereby becomes rancid, which diminishes the consuming value. According to Freu- denreich the fermentation is principally produced by four varieties of organisms which include yeasts, two streptococci varieties, and one microbe described as the Bacillus caucasicus. The yeasts are the Torula kefir and Saccharomyces fragilis, both of which ferment lactose. Investigations which have been re- cently conducted by Kuntze showed that the bacteria of Kefir eon- sist of an aroma-forming rod which produces casease and alcohol, and a lactie acid long rod which at first acidifies the milk and then renders it alkaline. They are the Bacillus esterificans Maassen and the Bacillus kefir classified by Kuntze as belonging to the group of butyric acid bacilli (cited by Weigmann). These bacilli inoculated Kefir. ie into milk, together with ordinary lactic acid producers, living in symbiosis with yeast, form granules which grow to raspberry sized clumps and nodes. Sponge-like masses of ruffle-like appearance, the so-called Kefir kernels result, in which are included the neces- sary varieties of microbes. In dried condition these kernels are of the size of millet seeds, but after treating with warm water or warm milk they swell and proliferate in the milk up to the size of a fist. The small young kernels are the best, as the larger readily degen- erate, become slimy and crumbling as compared with the elastic granules of more recent development. In order that they may again produce good Kefir they must be subjected to treatment by washing, drying in the sun, etc. The Kefir kernels may be purchased. The origin of the Kefir kernels, that is the microbe colonies which are clumped in the kernels, is not known, but the primary de- velopment may have some connection with the method of ferment- ing milk in containers made out of goat skins. If it is desired to prepare Kefir it is necessary to first obtain the kernels which may be purchased. The Kefir kernels are allowed to soak in boiled or lukewarm water, and then they are transferred several times (3 to 5 times) from one warm milk into another, the milk being poured off every 3 or 4 hours. The utilizable Kefir kernels increase in size during this time through further swelling, and as a result of becoming lighter in weight through absorption of carbonic acid they rise to the sur- _ face of the milk, whereas kernels in which one of the varieties of microbes for some reason or other became destroyed and degener- ated remain on the bottom of the vessel. If the degenerated variety of microbes recover through longer treatment with raw milk, and if the proper relation of symbiosis again appears, then these ker- nels are satisfactory for the production of Kefir. This condition is manifested by the kernels rising to the surface of the milk after some days. If a tablespoonful of these kernels is added to about one-half - liter of milk and this is allowed to stand for from 8 to 12 hours at 14 to 18 deg. C., with frequent shaking, then a primary or mother Kefir is obtained, from which through further fermentation in corked bottles the Kefir may be pr epared ready for use. The ‘‘millets of the prophet,’’ the Kefir kernels, are strained through a sieve, and the homogeneous fermented milk is filled into hottles, or from the strained fluid a considerable quantity is poured into a ‘bottle, to which boiled milk cooled to about 20 deg. C. is added. The bottle is then closed and allowed to continue. to fer- ment for from 24 to 28 hours, at from 12-15 deg. C. In this process the casein and serum separate but may be “readily homo- genized by shaking. The Kefir is then ready for consumption, and represents a thick, sour, aromatic fluid of a pungent taste, with a remarkable nutritive value. A similar product is prepared by the nomadic population of 174 Milk Preparations. Southern Russia, Siberia, and Central Asia, which represents a milk wine made from the milk of mares and asses, and which is known by the name of Kumys. In the preparation of Kumys, aleohol and carbonic acid fermentations are the principal processes. After long fermentation Kumys contains up to 2% of aleohol and 1% or more carbonic acid. Bacteriologically Kumys is of similar composition to Kefir containing yeasts, lactic acid, streptococci, and the Bacillus kumys (Sechipin), which is a facultative anaérobie microbe which splits up milk sugar with the formation of lactic acid and alcohol and peptonization of the proteids. These act together and form after several days a delicious drink of white color, and creamy con- sistence. Special varieties of milk, containing much sugar, are best adapted for the preparation of Kumys but cow’s milk is the least desirable. Gioddu, the buttermilk of Sardinia, is prepared from boiled milk cooled to about 35 deg. C. To four parts of milk one part of old Gioddu is mixed, the Gioddu being added to cow, sheep or goat milk. The fermentation is produced by the Bacillus sardous in symbiosis with the Saccharomyces sardous. According to Grisconi the Bacillus sardous belongs to the streptobacilli. The preparation of buttermilk constitutes an important branch of the utilization of milk in all countries. In northern Bavaria the milk is usually set in large earthen pots and allowed to undergo voluntary fermentation. Jn southern Bavaria and in the Bavarian forests the ‘‘fall milk’’ is utilized for the preparation of the ‘‘sour soup.’’? By keeping buttermilk and continually adding sour skimmed milk to it a fermenting product is obtained which is thickened by the removal of the whey (Herz). In Sweden and Norway a milk product is known under the name of ‘‘thick milk’’ (Tatmjolk), which is produced by slime and lactic:acid producing bacteria which vegetate on the leaves of the butterwort (Pinguwicula vulgaris). The leaves of this plant are placed on the bottom of the milk vessel and milk poured over them, whereupon the milk becomes so thick in several hours that it must be cut with a spoon or knife in order to be taken into the mouth (Weigmann). New milk may be inoculated with the residue of old milk. The necessary preparations of bacteria for the making of special forms of popular buttermilk may at the present time be:purchased in the market. In using any of these ‘‘ferments”’ the directions for use should be carefully followed, since at a tempera- ture either too high or too low an overproduction of undesirable bacteria may readily take place which would make good results im- possible. Even if the directions are carried out most accurately, the propagation from milk to milk may be a failure since the hiolog- ical properties of the bacteria are not absolutely constant; the microbes ‘‘grow wild”’ and their pleasant qualities are lost, or they may change, assuming undesirable properties. Table LV. Butyrie acid bacilli in boiled milk. kept for two days at 37°C. 1x 1200. B. Film of Yoghurt. Bacillus bulgaricus and lactic acid streptococci. Gram-safranin stain. 1 X 1200. Ernst, Milk Hygiene. Bitter Milk. 5 _ Porcelain vessels and bottles made from glass free ae lead are most suitable for the preparation of buttermilk, since the butter- milk may extract lead from enameled earthenware and from pots whose glazing contains lead in its composition. According to Chlopin 0.84 mg. of lead was extracted from 100 em. lactobacillin-buttermilk; in a “second portion (300 gm. butter- milk) which was five days old, the amount reached 7.86 mg. Briick- mann obtained similar results: 300 gm. of ordinary buttermilk con- tained after four days 4.2 mg., and after six days 5.7 mg. of lead, when this product had been prepared in pots with lead-containing glazing. Defects of Milk. Bacteria produce certain modifications in milk which partly on account of their frequency are designated as normal processes, or again others appear which are less frequently observed, occur- ring only under special conditions and therefore are known as milk defects. The modification, as has been seen, may be even desirable, as for instance in cream souring and cream ripening for butter making, or in the preparation of Kefir, Yoghurt, and buttermilk, or it may be undesirable and injurious, spoiling the milk, and having a disturbing influence on milk utilization, espe- cially i in its use for drinking purposes. Among the changes in milk there are those which appear fre- quently, and others which are very rare. Under conditions which favor propagation of peptonizing bacteria (staphylococci, sarcina, anthracoides, mycoides, mesen- tericus varieties, fluorescens, pyocyaneus, ete.), the milk attains a bitter taste. For instance if uncooled milk is filled into cans which are immediately closed it ‘‘suffocates,’’ acquiring a strong stable odor which may even reach a putrid character, causing a solution of the casein by reason of which the milk no longer coagulates; or the appearance of a bacterial rennet produces a rennet- like pre- cipitation of the casein, and the milk coagulates without turning sour. It is ‘‘sweet- coagulating. ’? By the action of peptonizing micrococei, which in part are psychrophilic the development of a bitter taste may occur in thoroughly cooled, and even in excessive- ly cooled milk. The bacteria of the colon group when the condi- tions of their propagation are favorable may produce an odor in milk ranging from aromatic to rancid, or some varieties of this group which have grown on mangels may confer the odor of man- eels to the milk. A bitter taste in milk may also occur from the feeding of foods containing bitter substances, thus for instance from the feeding of lupins, vetches, mangels, camomile, beet leaves, wood-fern, raw potatoes, mouldy or spoiled hay, straw, ete. It may however be accepted that the development of a bitter taste in’ milk usually 176 Defects of Milk. results from its contamination with varieties of bacteria vegetating on food substances, which enter into the milk directly from the stable air or indirectly with the manure and litter. They then con- vey to the milk this altered taste. Experiments to confirm these views have been undertaken quite recently by Weigmann and Wolf (Kiel). Defective flavors are frequently present in milk. Of 1,000 retentions made during 1909 in Munich, 90.50% were on account of souring, 14.6% on account of soapy taste, 18.25% rancid, 2.19% fecal contamination, 8.76% oily, 1.46% bitter, 2.92% granular, 2.19% sweet-coagulating, and 1.46% on account of slimy conditions. Representatives of the colon-aérogenes group may actually be cultivated until they become aroma producers if they are allowed to grow for instance upon media made from rape leaves. If an adaptation of these and other bacteria to the ingesta within the gastro-intestinal canal is admitted, then an acquisition of certain other properties, depending on the consumed feed, is readily conceivable. Weigmann and Ritland and Jensen demonstrated such ‘‘rape bacteria’’ in milk having a rape-leaf taste; the milk at the same time had a stale taste and an odor of dish-water. The author ob- served a distinct phosphorus taste in cases in which the milk was placed without being cooled into unclean or poorly cleaned covered cans. Animal and fecal odors result when freshly drawn milk is placed into covered cans without airing and cooling. In these cases the vegetation of anaérobie and facultative anaérobie bacteria may play a part, and the temperature may have an effect on the bacterial elective conditions. The milk attains a taste like animal viscera if it contains bacteria of the mycoid, megatherium or fluor- escens group. Fishy taste of milk may result from pasturing cows on marshy meadows which have been inundated. In these instances the pres- ence of various other varieties of bacteria should be taken into consideration. The multiplication of the Bacillus lactis saponace: (Weig- mann) and the Bacillus sapolacticum (Eichholz), produces a soapy condition of the milk. The milk attains a sharp, rancid, soap-like taste, and when cold it reminds one of valerian; in a warm state it has a sharp, soapy odor. In shaking such milk a fine, vesicular, persistent, tenacious foam results. The change appears in thor- oughly cooled and excessively cooled milk, and in the cold season of the year and in cold rainy summers the bacteria are psychro- philic, originating from the feed and straw. The Bacillus lacticus saponacei grows well at room tempera- ture, liquefies gelatin, and produces a slight yellowish shimmering coloring matter; the growth is aérobic. The Bacterium sapolacti- Blue Milk. LAE cum grows similarly. It is not supposed to liquefy gelatin. The nutritive media become fluorescent. The propagation of butyric acid bacteria causes rancidity of milk, as does likewise the multiplication of bacteria which spilt up fats, for instance the Bacterium lipolyticum. The appearance of the milk defects here mentioned may sometimes be confined to the product of a single individnal in the stable. The milk of one or of several cows may manifest these defects which may be retained persistently in spite of changing the feed and disinfecting the stable. Weigmann mentions a case in which, with uniform feeding and care of the animals, the milk of only one cow developed a fishy odor, and to such a marked extent that the milk of the entire herd became fishy (possibly the udder of this cow was diseased). The same author mentions another case which occurred on an estate in northern Germany. In that instance the milk of the Montavania cows in the stable was constantly rancid, whereas the milk of the Holstein cows was faultless, although the animals were all kept under the same conditions. The Bacillus lipolyticum was found to be the dis- turbing bacterium. It is noteworthy that the milk of the Montavania cows was frequently bloody at the same time. Therefore it is possible that the elimination of the aroma bacteria took place from the affected udders, that is, the same bacterium was also the cause of the inflammation of the udder. However, it is more likely that through the secretion of the affected udders conditions were established in the milk from the Mon- tavania animals which favored the propagation of the Bacterium lipolyticum in the milk, or probably the bacteria were present in the milk cisterns of these cows as harmless saprophytes, and the blood content of the milk may be attributed to some affection of the udder (yellow garget), which had no connection with the cause of the rancid milk. It has also been proved that other changes in milk may per- sistently occur in the secretion of certain individuals so that it appears as if the causative agents of the changes in the milk may at times exist as saprophytes in the cistern (Schultze), or that they have at least multiplied in the excretory duct of the cistern. Thus Schultze proved that in the appearance of ‘‘blue milk”’ the defect can only be removed by a thorough cleaning of the sta- ble, animals, milk vessels, and all creamery utensils, and the milk cisterns of the animals must also be treated by antiseptic infusions of the udder. The ‘‘blue milk’’ is produced by the Bacillus eyanogenes, a Gram-negative, aérobic, actively motile, unipolar, flagellated bacillus, with rounded ends, about 0.4u thick and 2.44 long. It is also known as the Bacterium syncyaneum Hueppe (Heim). Growing in sour milk the bacillus produces sky-blue to indigo-blue spots which gradually become confluent. The bacillus attacks the casein, and produces alkali besides a coloring substance, the triphenylrosanilin (Erdmann), which, depending on the reaction of the nutritive media, appears greenish or pale blue, violet or indigo-blue, or blackish-brown. The Bacillus cyanogenes in itself is colorless. The coloring is less typical in sterile milk; a dirty bluish-gray discoloration with a reddish hue of the cream occurs, the color gradually diminishing in the deeper parts. Indigo-blue spots develop only in sour milk (Heim). The changes which occur in milk appear to be especially fre- quent in certain localities; in others they are more rare and appear to have a connection with the properties of the soil. Pastures rich in clover are supposed to favor the appearance of the defects while in woodland pastures they have not been observed, or at least: only exceptionally. This would explain why the defects occur in cer- 12 178 Defects of Milk. tain periods during the feeding of the incriminated feeds, or while the cows are feeding in certain pastures. According to observa- tions they are observed more frequently in the fall, and during wet, foggy weather than during other periods. These defects persist tenaciously in creameries and dairies and can only be eradicated after a thorough determination of their origin. Disinfection of the milk room and utensils with milk of lime and hot soda solution, and extending this disinfection to the stable in association with cleaning of the animal and possibly an- tiseptic infusions of the milk cisterns may yield the desired results. Another organism causing ‘‘blue milk’’ is the Bacterium cyan- eofluorescens (Gangemeister). It is actively motile, bipolar, flag- ellated, grows on gelatin in the form of whitish colonies with in- dented borders and produces a fluorescent coloring matter in the nutritive media. The culture has an odor of trimethylamin and putrid fish. The bacteria produce dark blue spots in milk which change to a sky-blue color after coagulation of the milk. Other blue bacteria are those which occur on hay dust, in water, and in sewage in the vicinity of cheese factories, in ditch-water, and also the bacteria cultivated by Voges, Claessen, and Beijerinek which have been described under the names of B. ceruleum, B. indigan- aceum, B. cyaneofuscum. According to the observation of Weigmann and the deserip- tion of Hallier certain hyphomycetes may also possess the faculty of producing a blue coloration; this is accomplished by the ae- tion of the blue coloring matter which they harbor. In the zone of the milk supply of Munich ordinary milk de- fects occur very rarely; the author observed them in only one dairy, and was able to trace the trouble to a certain farm. An- other defect of milk occurs much more frequently in the vicinity of Munich, the cause of which, according to the author, has not yet been described. It concerns the production of brownish milk. The bacterium of brown milk appears to he closely related in all its characteristics to the producer of blue milk; it is 2.4u long, 0.54 broad, unipolar, flagellated, actively motile, Gram-positive and remarkably resistant to drying. In gelatin it grows especially well aérobically as a fine, iridescent deposit, which later becomes somewhat thicker, turning to a chestnut brown color. The oxygen zone of the lactose gelatin retains a saturated brown to deep brownish red discoloration, the nutritive media becoming alkaline to litmus. A culture of the brown milk organism may be readily produced in milk by rubbing traces of the culture of milk having such a defect upon the bottom of a large Petri- dish, and pouring over it fresh (not sour) milk. In most instances after 15 to 20 hours ocher-colored to sepia-brown spots develop in the cream layer, which enlarge ani coalesce, conveying to the milk a milk and coffee-like appearance. After coagulation the superficial layer of milk again liquefies; whether this is brought on by the bacteria of brown milk alone or by peptonizing bacteria which multiply especially well when mixed with the bacteria of brown milk, which render the media alkaline, has not yet been established. The skimmed milk is not discolored by the Bacillus fuscogenes. The brownish color gradually diminishes from the surface down and at a depth of 5 mm. it disappears. If the milk is allowed to sour the appearance of gray, orange- red, red, yellow, green-fluorescent and violet spots may frequently Red Milk. JEAS be observed, which cause a glassy, transparent thickening of the wrinkled yellowish-white velvety layer of the oidium covering, or they penetrate into the depth of the jelly-like layer of the milk. Thus under certain conditions the Bacillus violaceus, Bacter- ium janthinun, Bacillus lividus, and Bacterium amethystinus, a water organism, may appear in violet spots (Schroeder, Zopf, Mazé, Fliigge and others). Greenish-yellow spots and discoloration of the entire sour milk are produced by the Bacillus fluorescens which varies ereatly in its characteristics, at times liquefying gelatin, again only dis- coloring it. It is a short rod with motility, but without spore formation. A red coloring matter is produced by the Bacillus erythro- genes Hueppe, which coagulates milk, but liquefies it later through peptonization, coloring the whey red. According to Gruber a flagellated short rod, the Bacillus lac- torubefaciens is supposed to produce a slimy condition of milk with the formation of a red coloring matter. Other bacteria such as the Micrococcus cerasinum (Keferstein), the Sarcina rosea, the Bacillus prodigiosus and others, form red spots. Red varieties of yeasts have also been found. The author demonstrated through the examination of a dirty and dry milk pail that the layers of color which adhered to dif- ferent parts somewhat like red varnish consisted of blue-red yeasts which had grown on the dried milk residue. The accumulation of color was present in the yeast cells proper, which on examination showed a reddish transparency. Their attempted cultivation was unsuccessful. The discolorations of milk may vary from red, and pink, to rust-color and orange. Yellow coloration sometimes only of the cream, at other times of the entire milk is caused by the Bacillus synxanthus (Schroter), the Sarcina lutea, the Sarcina flava, and Bacterium fulvum and others. Wild yeasts and moulds, which have been observed by the author may also cause a yellow coloration of sour milk. The Bacillus fluorescens, may at times cause a_yellowish-green discoloration. Other bacteria again show the action of their vegetation by the development of a tenacious slimy consistency of the milk. Strains and varieties of the peptonizing bacteria in which acid for- mation is dissipated and the peptonizing action of which retracts against the properties of producing rennet-like substances, may in a few hours eause a casein coagulation, and thereby convey to the milk a granular consistence. This defect is relatively rare, and on the contrary the milk may become non-coagulable, slimy and bitter. More frequently, especially by keeping the milk in a warm place, a change of the milk to a slimy consistence may be observed. The action of the slime-forming bacteria may appear in two forms, 180 Defeets of Milk. and render slimy either the entire milk, or the casein is precipitat- ed and only the whey develops a strong tenacious, stringy consistency. The cause of the slimy condition may be produced either by a slimy change of the sugar, which is accomplished with the form- ation of a high molecular weight body, the galactan or the viscose, or by the swelling of the bacterial capsules which form a mucin- like substance. The best known producer of slimy or stringy milk is the Strep- tococcus hollandicus, the cause of the ‘‘long whey,’’ which is con- sidered by Weigmann as a degenerated streptococcus of lactic acid fermentation. If cultivation of the producer of the ‘‘long whey”’ is continued at 35 deg. C. it loses the property of producing slime, and changes into a lactic acid producer. From various groups of bacteria the following have been proved to be slime producers: Bacterium lactis longi—a strep- tococcus—in Swedish thick milk (Troili Petersson), Micrococcus (streptococcus) viscosus (Schmidt-Mihlheim), Micrococcus mu- cilaginosus from slimy cream (Ratz), and Streptococcus burri from stringy whey. Slime is further known to be produced by the colon-aérogenes group (Emmerling, Schardinger), the Bacillus guillebeau, as well as the Bacillus lactorubefaciens. Adametz, Duclaux, Gruber, Ward, Kckles, and Marshall have also isolated slime producers from milk, whey, food substances, straw, stable air, and spring water. Other defects of milk which are associated with change of consistency (and color changes), are produced by milk drawn from affected udders, which subject has been discussed in the section on ‘‘Diseases of the Udder.’’ Considering the living requirements of the special varieties of bacteria, the defects of milk appear to be especially frequent under certain weather conditions and in certain periods of the year. Thus the milk dealers of Munich complained of the appearance of defects of taste, especially in the cool and cold period of the year, and at the time of changing the animals from stable to pasture feeding and vice versa. The cause may lie in the fact that with the beginning of the dry, that is stable feeding, the microbian flora of the intestinal canal and of the forage and the stable air is different from that existing during the period of pasture feeding, and thereby other species of bacteria, aroma producers, contaminate the milk; likewise in certain cold climates and in certain methods of keeping milk the bacteria, excepting the lactic acid producers, find just the requirements which aid them in their propagation. In 1909, the following defects of milk were found among 1,000 samples examined monthly: 181 Various Defects. 89 LIG QL TL 8G Ge 96° 9FG V6G ee ee . ee . . ee 69 19E 192 . . . . . ee . . ° ee ee Il . . . . . ee ee ee ee eee ee GG 066 oe ee eee ° . . eee oe ° v0 19 VG 99E ees saasepy 2a WANO MeL ped Seer eeeeeees KUT “SUT}LTUSROD JOOMG “7° TBTNUB.L) ee ter vel Herre £10 17 [QuaMneral 8488} MOD Pieter ca “7+ Advog F228 > ayo eee es Ay AI Se ee ee G V YO TL [See | Ce | 182 Defects of Milk. At the same time it appears as though the spoiling of milk, for instance by souring, is less influenced by the temperature, which of course may be of importance, than by the atmospheric pressure. It could hardly be attributed to an accident that, ex- cept at harvest time when the milking is sometimes hurriedly done, the number of samples spoiled by souring were almost in recipro- eal relation to the measured average value of the atmospheric pressure for the month. Likewise in several months a certain parallel exists between the occurrence of dirty milk and souring, so that the dirt is present in largest amounts during August, September, October and November. Months in which milk contains a great deal of dirt appear also to favor the requirements for the development of a putrid taste. (Height in June, August and October, harvest time.) Dur- ing this period the milk is not aired and cooled, so it ‘‘suffocates.”’ The cans are not cleaned, and all dairy work is slighted. Direct contamination with cow manure appears to be of Jess importance in the development of an animal flavor, than pollution with bacteria from the skin of the cow, which may contaminate the animal while in pasture. These views are strongly supported by the experiments of Wolf and Weigmann, who proved the identity of the bacterial flora of the defective milk with the bacteria which were cultivated from the pasture plants, and by the experiments in which the authors succeeded in reproducing artificially these defects by using special bacteria. This view is also supported by the observations of the author. A milk dealer complained about the bad taste of milk in a certain delivery. It was noticed that only the evening milk of the farm, and not the morning milk possessed the defect. Before the evening milking the animals were kept in a pasture during the day. It was remarked from the beginning that the morning milk did not have the taste, which was the more suprising since the animals by standing in the stable during the night must have affected the purity of the stable air. Nevertheless the evening milk which was obtained in the stable after a sufficient airing and cleaning, possessed the objectionable taste. Of course the time could have played a part since both the morning and evening milk were delivered at the same time, the evening milk being allowed to stand all night at a temperature of 12 deg. C. The milk was kept in a milk room next to the stable. The conditions, however, were not changed by removing the milk immediately after milking, to a well-ventilated room, cooled by ice. The passing of the odoriferous substances into the milk directly from the food could be excluded since the substances could then have been demonstrated in the morning milk as well, and therefore the only explanation which remained was that while lying down the abdomens of the animals became contaminated with the bacteria of pasture plants (meadow grass and clover). These bacteria contaminated the evening milk during milking in the stable, whereas the morning milk was principally contaminated with bacteria from the bedding. All other factors could be given about equal consideration. That the age of the milk did not play a part was proven by the fact that the morning milk in spite of longer keeping during both cold and warm weather in exposed or covered vessels, had never been affected by the disagreeable taste. Tt is almost impossible at the present time to establish definite relations between defects in milk and contamination of milk with bacteria, since the propagation of the bacteria causing the defects may be influenced by the most varied factors. It should be especially emphasized that bacteria of one and the same species may under certain conditions produce different defects in milk, depending on the accompanying conditions, as for instance whether they are associated with one or several other species of bacteria. Coagulation Types. 183 According to Wolff and Weigmann the Bacterium fluorescens possesses the characteristic of producing by itself an ester-like odor, while together with the Bactervum mycoides and the Strep- tococcus lacticus it produces a disagreeable aroma, and finally with the Bacterium megatherium, B. mycoides, and lactic acid bacilli it produces a cheesy odor. This of course renders the study of milk defects difficult, since a bacterium cultivated in pure culture may show an entirey different action than when present in milk in a mixed culture, and mixed culture experiments with the entire flora would become necessary. Types of Coagulation. The decomposition and fermentation microorganisms, which develop in milk, are utilized in the examination of milk that is in- tended for the manufacture of cheese. A fermentation test is made from each delivery of milk, and after a certain time each sample is tested for odor, taste, and in regard to its appearance and visible changes. According to Jensen the fermentation may be distinguished as: 1. ssl) 1. s cess nena 20 Comineatier This. .at, 25)deen hadeantacidity of 255.40 +4.,) 02k e me eeoD 10 min. after 12 hrs. at 25 deg. had am acidity of...........:............ 22 Sun yakcer wd rssat 25 des. hadsanvacidity ot. >... 0.290425. anes ones 18 (emuingattermkoghrsat 2o0deo- hadwankacidity: Ol. / sh 452 once see ee 28 Pp hoatter t2nhrs sah 2 decuhadiant acidity Ofer as... eco ele oe 15 To Mite: Baier U2) linishs he 25) leres lneiéh Ghat EGGhtin? Gite ede cae sabes Jeekabeess ae 25.5 iureater ll 2nhnsieat, 2ondecn hadsankaciditiv: (Ota: er sere cen 11.5 186 Reductase, Catalase, Ete. 2% hr“atter 120hrs. at. 2o/deo) had anjacidityroteene eee ns ee ee 15 3%, hr. after 12 hrs. at 25 deg. had an acidity of........................ 9 6% hr. after 12 hrs. at 25 deg. had an acidity OED Marne Nee hare a ee 9 7 hr. after 12 hrs. at 25 deg. had an acidity OL Se ate eeee eoee se seen 10.5 646 br: after? L2shrs.-at 25 der. had ian aciouby Olmert eee 8 7% br. after 12 hrs, at 25 deg. had an’ acidity Of. 7. 7.07.5 moe pee see 8 TtAchr. atter 12 hrs; at 25 der! had ancacidibysote: «cm seinen oe eee 7 S46 hr. atter 12 hrs} at 25 des. hadian acidity Of. - 7-2 eee eee 7.5 The findings of the author were very much the same as those of Jensen. Milk which failed to reduce in 20 hours had after 24 hours at 20 deg., from 7.4 to 10 degrees of acidity. The following table shows the results of the technique em- ployed in testing milk, where the reduction number is understood to mean the number of drops of methylene blue solution which in a given time was completely reduced by 5 ¢. ce. of milk: Degree of acidity After 24 hrs. Time required at delivery at 20 deg. for reduction Reduction number 7.0 7.4 20 hrs. 0 6.2 8.6 20 hrs. 0 6 10 20 hrs. 0 6 9 20 hrs. 4 7 10 20 hrs. 0 6 24 4 hrs. 2 6.4 26.5 8 hrs. 10 6.5 26 8 hrs. 6 6.2 24 8 hrs. 8 6.2 27 8 hrs. 6 6.8 25 8 hrs. 4 6 14 8 hrs. + 7.8 30 6 hrs. 4 6.5 28 2 hrs. 2 0.2 32 1hr. 2 6 34 1 hr. 2 6.2 38 1 hr. 10 8 40 5 hrs. 10 10.5 26.4 0.5 hrs. 10 6 30 6 hrs. 2 These numbers were obtained from a great number of sam- ples during work at the milk control station, without any selec- tion. They show that milk which sours rapidly, and is therefore at the end of the incubation period, also reduces rapidly; there exists, however, no absolute constancy in the parallelism, neither with the values of acidity in milk after twelve to twenty-four hours, nor with the values in samples of fresh milk. After thorough souring the reduction power of the milk again diminishes for a time. This may be due to the fact that the acid reaction inhibits the reduction power—as a matter of fact the rapidity of reduction is again considerably increased by the addi- tion of sodium earbonate or bicarbonate—and also because a non- reducing organism, the acid streptococcus, outgrows the other bacteria. The addition of an alkaline solution brings about acceleration of the reaction only in sour milk, while in milk with low bacterial count the reaction is retarded, but this may be overcome when through acid formation neutralization has taken place. Bacterial Catalase. 187 _ Antisepties, such as boracie acid, salicylic acid and formalde- hyde, inhibit or destroy the reduction power of bacteria; the same result.is obtained by heating, which destroys the life of the vegetating bacterial cells. Milk which has been heated for 10 to 30 minutes at 80 to 100 deg. C. shows only the slightest reduction power, which increases again only after the recurrence of bacterial multiplication. It should be emphasized that milk, in spite of being spoiled to a marked degree, may have a slow reducing power, as for instance soapy milk, provided this condition is not associated with extensive bacterial contamination with other species of bacteria. Although the bacillus of soapy milk reduces very rapidly, soapy milk in itself is only capable of bringing on this reaction to a very slight degree, which probably is proof that defective flavors may result even when only a very slight bacterial growth has taken place, although the bacterial action is of tremendous importance. For the completeness of this chapter it should be mentioned that milk very rich in bacteria, which has been sterilized by heat, reduces also the formalin methylene blue solution as a result of the original bodies in milk, a property which has nothing to do with the Schardinger reaction. The formalin methylene blue reducing principle in market milk is also a pre-formed substance, which occurs in milk drawn under sterile conditions (original ferments). Bacterial Catalase. Similar to the power possessed by body cells and body juices, bacteria have the ability of splitting gaseous oxygen from hydrogen peroxide solutions. This property may be observed in many bac- teria, but it should be mentioned that not all species of bacteria possess it, and that certain bacteria have a specific power in this direction. Koning and Jensen made confirmatory statements to this effect, having found that the acid streptococci of milk do not split H.0,. The author’s experiments confirm this observation. Jensen made an especially interesting observation, namely, that the bac- terial flora present in milk during the incubation period of souring usually possess strong catalytic properties. The following data are taken from a work of Koning, arranged according to the catalase figures: Species of Bacteria Catalase test Reductase test Be produgiosus .........---- REN ee eee Os pinrcte te rene 58 15 minutes 1B, JOROUCUS BOD sasccaeasonoo0DcebdG00cHD oaouGDE 57 15 minutes Mink loeemerminm®, Ie ssooccccudcscogssucboonooeode 5 BS 80 minutes B. fluorescens liquefaciens ........-+++++++++-+-:- 53 13 minutes By COU COMMIS scbcconoeddsoorduncbannobonda soe 39 17 minutes 18, We@tic CHEW, TIWENO® aoocescaccescocccocanscssen 32 12 minutes Shomlol® quae loneneime, Ike oc so ccc cones econ ecocouunGe ae 3 90 minutes IB. TUOSCRUGRIGUS. Sa5cccebcocopesegnovoonucusoueEst 3 60 minutes B. fluorescens nonliquef. ....+++.+ sees ee eee tees 29 15 minutes 188 Reductase; Catalase, Ete. Stable. air bacterta 42 sae e cee eee 28 90 minutes Bs. SUD TALUS Po ae So alee te lesen ate hee cee ee 1h ( 40 minutes Milk ‘bacteria, U7 rector canned Oreo) ak eS ee eee 15 90 minutes Be My COCs fo canis asec ckne ate oR te ee 11 90 minutes ONAN IACTIS A AS ik ee ee 11 90 minutes SEPSANAS HTS MIONGUS: scien Se ae eae eee 0 90 minutes From these figures it may be seen that frequently with a high catalase number a very rapid reduction time may be present. Jensen found similar conditions in his investigations; he, however, expresses himself as believing that a parallelism of both factors does not prevail. Arranged according to catalase values expressed in figures, giving the number of c. c.’s of oxygen formed, the relation between catalase and the time of reduction is 2as follows : Catalase Reductase IY) FRACS OMICS NG ope oO Ove Ero uOAneGoomone 27 ¢. ¢. 7 minutes 1B $oh4 DRINRCU SEY AO) 1 UM Se athe Cicer DiceenCE rece Ge eabich Ged Gis iO 27 ¢.@. 5 minutes IBV OORGLOSUS. Uavere¥e acts a siete she aucicleysisne tens aie ere rears 27 ©. & 7 minutes MACK OCICONGIC Lia: cyto Gears etree ices Ree CIT 27 @.¢. 4 minutes MIG ONO CRRA cree creusica tal isla cceee nies Cot ete na nem ee Bees 27 ¢. @. 3 minutes JERI OIG DREN O DROIT OID hot IO CO SIsIee 18 ¢.¢@. 5 minutes BE KAENOG ONES Ah caste AR Ee 9e.¢. 10 minutes BANA) COLES.» maw she shot scts at aeoenee ete ietts eer oie 7 ¢. @. 12 minutes Be QENETUICAMS!) crere aie ese scieho) Noketolaye rereu en loiaee eee leve. 10 minutes With other bacteria, for instance, butyric acid bacteria, there appears to be no relation between the reduction power and the development of oxygen, whereas with certain lactic acid producers, for instance, the streptococci and cheese bacilli, the inability to develop oxygen coincides with the long time required for reduction. In unspoiled milk during the incubation stage of souring and at the beginning of souring at the end of this incubation stage, the bacterial catalase will always have to be considered, but in general the bacterial action in slowly reducing milk is very slight. If in the latter instance high catalase values are obtained then usually the catalase originally present in the milk is responsible for it. Koning further showed that catalase increases with the age of milk, and with a rapid angle of incidence. The line of incidence in fresh milk is at first only slightly bent, later more or less so, whereas old milk uniformly shows a rising line. Spindler’s recent experiments confirm this statement. From the investigations of Spindler, however, it may be observed that during the time when milk is fresh enough for drinking purposes the fluctuations are only very slight and the catalase value obtained is always greatly dependent on the original catalase value of freshly drawn milk. Faitelowitz indicates that catalase multiplies many fold after keeping fresh milk at room temperature for 24 to 30 hours. Through heating to 70 deg. C. the ‘‘bacterial catalase’’ is destroyed, or at least the bacteria are attenuated in their action to such an extent that the oxygen-splitting property becomes almost nil. Chick has already ascertained that this inactivation of the bacterial catalase may be abrogated in a certain time by inoculation of the heated milk with raw milk and Koning states that old pasteurized milk, or milk freshly pasteurized with insufficient heat, splits the H.O.. The catalase test is therefore recommended by Kniisel for the examination of pasteurized milk as to its suitability for drinking purposes. Acidity of Milk. 189 It is to be regretted that the bacterial catalase cannot be separated from the original catalase, so that it would be possible to draw definite conclusions from the catalase findings of market milk, as to whether the catalase quantities which are demonstrated were present in the freshly drawn milk or whether they have been subsequently formed by bacterial growth. Wolf claims that milk which reduces slowly and shows a strong catalytic property by the formation of large quantities of oxygen should be suspected of containing secretions from animals with affected udders. It would be impossible to draw conclusions based on this statement in those cases where rapid reduction occurs coincidently with strong catalytic action. Degree of Acidity. In discussing the original properties of milk it was mentioned that casein, acid “salts of milk, carbonic acid, ete., give to milk an acid reaction to phenolphthalein. Even immediately after milking, in order to Revue neutral- ization of the miik against phenolphthalein, several ec. ec. of sodium hydrate are required. The number of cubic centimeters of a normal Na OH dilution which are needed to neutralize a certain quantity of milk are known as degrees of acidity. The number obtained varies, depending on the method and dilution employed. Thus Soxhlet-Henkel, for instanee, employed 100 ec. ce. of milk and 14 normal Na OH and obtained an average value of about 6 to 7 degrees of acidity. Jensen, who works with 7 normal Na OH, uses on an average 18 to 19 ¢. ¢. Thorner dilutes 10 ec. e. of milk with 30 ec. ec. of water and titrates with 74> normal Na OH. The degrees of acidity, as determined by Dornie, are higher than those of Soxhlet-Henkel: He uses 10 «. e. of milk and alkali which contains 4.445 gm. Na OH to 1000 H.O. 75 ¢. ¢. of alkali, according to Dornie, is equal to a degree of acidity. Schrott-Fichtl and Dornic suggested as an advantage the drop- ping of the ‘‘scale of degree of acidity’’ and employing an alkali, 1 ec. e. of which would correspond to 0.01 gm. of lactic acid, or to figure the degree of acidity on the basis of lactic acid. Then 1 ¢. c. of 7 alkali would correspond to 0.009 gm. of lactic acid and 1 e. c. of 144 normal Na OH=22.5 om. Of course, it should be remembered that the neutralization of the alkali does not correspond entirely to the amount of lactic acid present but depends also on other factors, for instance, on the proportion of acid phosphates, carbonic acid and casein. Only the increase in acidity which is obtained by a compara- tive testing of fresh milk and an older sample of the same milk, should therefore be considered as lactic acid, since Henkel proved that free lactic acid is not present in freshly drawn milk. 190 Reductase, Catalase, Ete. The degree of acidity of milk depends on the lactation period. Colostrum, milk of animals with affeeted udders, and milk from freshly milking cows have an abnormally high acidity, while milk from animals in the last stages of lactation, and sometimes milk from affected udders, may be lower than normal. Besides these factors the degree of acidity of milk is also influenced by the growth of bacteria, the species of bacteria, and therefore by all factors which have an influence on the bacterial growth, such as cleanliness in milking, cooling, outside tempera- ture, age of the milk, ete. Plaut, for instance, demonstrated that milk which has been kept— At a temperature of showed multiplication of and voluntarily coagulated bacteria after after 10 deg. C. 48 to 72 hrs. 100 hrs. 15 deg. C. 20 to 24 hrs. 63 hrs. 20 deg. C. 12 to 20 hrs. 48 hrs. 25 deg. C. 8 hrs. 24 hrs. 31 deg. C. 7 hrs. 22 hrs, 37 deg. C, 5 hrs. 12 hrs. Koning has also kept milk at various temperatures and titrated the degree of acidity after varying periods: Kept at 7to9deg.C. Kept at 22 deg. C. Dee. of acidity Deg. of acidity with 14, NaOH Milkwatherdeliveny ova ancl ces ie eee teen ee 13.6 13.6 TAGELE? Reba MATTOUES O28 ewes anes (ale fee een eee bane 14.6 14.6 AE Gersa29) NOUTS cet it Wn rae a ee etek 14.6 20.6 Aer tall MNOUTS AK orn eae Ae roe he eee 16.0 62.6 ATER coo, OUTS ccs Aah nan aaa ee 16.0 71.0 Atiiere'G5) NOUTSe ene Aes Mes eae Ee 16.8 is Meher’. ie Ours... cee athe Sok natn 17.6 AEGer (SOM Ours Ase. tier etek a ORAL 18.8 of keeping the milk, therefore the acid formation varies in accord- ance with the same conditions during the same time. Koning’s experiments confirm these findings: Time of Milk in shallow vessels In tall cylinders delivery at 22 deg. at 37 deg. C. at 22 deg. at 37 deg. C. Shortly after milking.18.6 oe. ree ee After 24 hours...... 16.4 18.5 18.8 32.4 The degree of acidity depends, furthermore, upon whether fresh milk is boiled or raw; in boiled milk it is lower than in raw milk, and it also depends on the aeration of the milk. Milk drawn carefully into bottles 25 minutes after the milk- ing has 17.4; after being aired by pouring from a height of 14 meter, 16.4; after repeated aeration 16.1, and after boiling only 16 degrees of acidity (Koning). The escape of the volatile carbonic acid seems to play a part in this. Finally, the degree of acidity depends on the method by which it is tested. For instance, if the milk is diluted with water for the purpose of titration (method of Thorner, Pfeifer, ete.), then through this addition of water, a solution of alkaline calcium phosphate takes place and the acidity becomes less. Typhoid Fever from Milk. 191 Since the acidity varies immediately after milking, after lac- tation, among individuals, and even in milk from different teats, and from interrupted milking’, the immediate measuring of the degree of acidity constitutes no proof of the age of the milk. The periodically continued titration of the same sample may, however, be a good indication as to whether the milk has passed the incu- bation phase and thereby afford an approximate indication of the ‘‘age.’’ By ‘‘age’’ is not understood the difference in time between milking and examination, but a condition which may ap- pear in milk sooner or later, depending on the cleanliness in its preparation and handling, and on the outside temperature. This condition is effectively determined by the reduction of methylene blue. If the milk has once passed the incubation time the curve of acidity rapidly and progressively rises, when the milk is kept subsequently at temperatures at which lactic acid bacilli grow pro- lifically (20 to 37 dee.). Koning made a test of milk which at delivery gave a degree of acidity of 15.8 (445 n Na OH. :100), And showed after at 10 deg. 22 deg. 37 deg. C. ILC EIN AG ea eee ga 16.4 28.8 96.0 TO CST) eae ee or a 16.7 91.1 92.8 BURG ANStaivads he coke cola 2 102.4 105.2 ARNIS os pit. caer Ole a We) 96.4 144.0 DMCS? aeetin aes lt =P OLD 105.6 184.0 Gpaancee sc eee) 0 RD. SOE TCE eee a Ae. 1028 OAL Sie Cl ela Siiraa as cents cue ar 65.2 106.0 261.6 depend on the time and temperature alone, but also on the variety of bacteria growing in the milk, only general conclusions as to the aging of the milk can be drawn. Subsequent Contamination With Infections of Man. The occurrence of disease producing agents in milk is of interest from the standpoint of tracing the origin of disease, but from a milk inspection standpoint it is a most thankless field. These disease producers may originate from affected persons, or from healthy bacilli carriers, or they may reach the milk through infected material, as, for instance, infected water used in washing utensils, or as an adulterant, or in the treatment and preparation of milk products. That milk may become a transmitter of disease has been posi- tively proven. 1. Typhoid Fever. The causative agent may contaminate the milk through infected water, through vessels which were returned without cleaning from houses harboring persons affected with typhoid, through affected and convalescing patients who’ are employed in producing or in the subsequent handling of milk, and 192 Infections’ of Man from Milk. through attendants and other intermediate hosts, especially through bacilli carriers. Konradi positively demonstrated typhoid bacilli in such milk. Levy and Jakobstal discovered true typhoid bacilli in an abscess of a cow so that under certain conditions it should be considered possible for typhoid bacilli to gain entrance into the milk directly from the udder of the cow. 2. Paratyphoid Fever. All that applies to typhoid bacilli holds equally true for paratyphoid, and to other bacteria of that type, for instance the Bacillus enteritidis and the Bacillus paracoli. In these affections especial attention should be directed to the animals which are affected with intestinal inflammations, purulent metritis, and acute, severe inflammations of the udder, and also to stables in which white scours of calves and ealf-ill occur frequently. The possibility of the transmission of scours to man has been indicated by Lenz, Jehle and Charleton. Up to the present time, however, its certain transmissibility through milk has not been satisfactorily demonstrated. 3. Cholera. 4. Diphtheria. 5. Tuberculosis. Rabinowitsch demonstrated tubercle bacilli of human type in milk. 6. Scarlet Fever. The sanitary police or the authorities in charge of milk con- trol in all cases in which a suspicion prevails that such diseases have been transmitted through milk ean provide that the possi- bility of the continued spread of such infections should be pre- vented. The sanitary police authorities should continuously im- press upon all persons interested in the production of milk, and in the dairy industry, that there are always possibilities of the transmission of disease; and the attendant physicians should ecau- tion the patients and their families as to the danger of allowing it to spread further, and any violations should be dealt with to the extent of the law. The health authorities of a locality at every appearance of a dangerous epidemic should consider the possibility of the develop- ment of the disease through milk consumption, and should trace the places from which the affected persons and their families draw their milk supply. If from these investigations there exists the slightest cause to assume that the milk supply may be the original cause, the attending physicians should cause a further investigation of the matter. In the meantime the suspected milk should be rendered harmless by pasteurization. With these remarks an intrusion has been made into the chapter upon ‘‘the supervision of the milk traffic and milk control,”’ which will be given special consideration. Destruction of Bacteria by Heat. 193 The Destruction of Bacteria in Milk. it tz sur purpose to discuss briefly the destruction of bacteria in milk, which aims to free the milk from disease-producing germs and add to the keeping quality of the milk. In practice this is accomplished most frequently by heating, in which the following distinctions are made: 1. Sterilization of the milk; Simple boiling ; Pasteurization. If it is desired to judge the value of these methods of prepa- ration, the question first considered must be, what changes does the milk undergo through heating? Milk is a biological product the properties of which may be considerably influenced by cold and heat. It is generally known that after heating milk retains a so- ealled boiled-milk taste, and that this becomes stronger the longer the milk is subjected to a temperature of from 70 to 100 deg. C. SUT) The method of heating is important for the appearance of the cooked taste. Open boiling even for a short time produces a marked change in taste when compared with heating in specially closed utensils or in bottles after subsequent cooling. The curdling of boiled milk is more difficult than with raw milk; the boiled milk in curdling after a long time forms a loose, coagulum with less uniform consistency. This change is not so pronounced with heating between 70 to 80 deg. as in boiling and in heating to over 100 deg. C. Depending on the height of the temperature and on the length of time the heat is applied, globulin (at 75 deg.) and albumin (at 80 deg.) are precipitated. Proteids which are precipitated in milk by heating to boiling temperature disappear if the boiling is con- tinued. According to Peiper and Hichloff the intermolecular at- tachments of the proteids become loosened by heating to high temperatures, and leucin, tyrosin, ammonia, sulphureted hydrogen and phosphorated hydrogen are formed. If the heating has been conducted in poor earthenware or glass vessels, especially new ones, potassium silicate will pass into the milk. Fynn noted the absence of sulphureted hydrogen from heated colostral milk. The reaction became apparent only on the fourth day of lactation. The formation of sulphureted hydrogen and phosphoric acid in milk results from the splitting up of casein. Hydrogen sulphide can be demonstrated in canned milk even months after heating, whereas in sterile bottled milk, under the influencee of light and in the presence of oxygen, the sulphide of hydrogen is utilized for the formation of water and sulphur. In higher heating the milk becomes brownish through caramel- ization of the milk sugar and the lecithin content of the milk 13 194 Effect of Heat. diminishes, which, according to Kida, may be seen from the fol- lowing example: In 1000 e. ce. of milk, lecithin was present as follows: Unheated samples...0.474 9m. 0.474 0.505 0.467 0.462 0.517 Heated to 75.dee: ....0:44400m: ca. 7 ee ee Heated'to "sO: deae sc: . coe. 0.420 0.467 Heated to s9odeas.« 2.4222? 9 AE a Hented tio L00id ers. 20 22%. ce. eee Over T00 desrO tn. 22 PPP Diminishing amt. ...0.030 gm. 0.054 0.038 0.118 0.111 0.116 In percentage ....... 6.53 11.389 | .7.52°.25.27 20225 In heating, the proteids also change, peptone is formed and tricalcium phosphate is precipitated. The original ferments are especially susceptible to the influ- ence of heat. Through heating to a certain temperature the amylase, the peroxydase, the catalase and the aldehyde reductase disappear. The amylase and the aldehyde reductase disappear even at a temperature of 65, that is from 50-65 deg. C. Of course milk which has been changed in this way by heat must naturally be judged differently from a nutritive standpoint than raw milk. Out of 3,462 digestible proteids used in each 100 gm. of milk there remained undigested: iammiveaikedsimilk erm rats een 0.762 om. In heating for 30 min. to 80 deg. C....1.153 gm. 85 deg. C....1.493 gm. 90 deg. C....1.420 gm. 95 deg. C....1.540 gm. 100ides. C... -2i9iem Experiments by Briickler, Reiner and Eichloff showed that dogs fed for months on sterilized milk showed a good nutritive condition, and some of them even manifested a greater gain in weight than the control dogs fed with raw milk, but the latter were brighter, their blood was richer in ash, with diminished salt content; it contained more fibrin, had a higher specific gravity, and the structure of their bones was more dense and richer in ash. The bone marrow of the animals fed with sterile milk was more anemic, the periosteum of the bones separated more easily, and at times hemorrhages appeared on the borders of the diaphyses, such as occur in rachitis. The nutritive results in children which have for a long time been exclusively nourished on sterilized milk are similar. The infants become affected with infantile scorbutus, a symptom com- plex, which is known to the physician as ‘‘ Moller-Barlow disease,’’ and which disappears when raw milk is provided. From the above it appears that high prolonged heating of milk should be avoided, and if possible the advantages derived from the heating should be obtained by heating the milk for only Were ate a, oie Pasteurization of Milk. 195 a short time at a relatively low temperature, which when properly applied will appropriately destroy the bacteria. The vegetative bacteria may be destroyed by subjecting them to the influence of heat at 60-70 deg. C., for one-half hour, or to a temperature of 85 deg. C. for a half minute; on the other hand it is known that spores of bacteria not infrequently resist a tem- perature of 100 deg. C. and over. In practice it is advisable to abstain from the sterilization of milk with high degrees of temperature, and to apply pasteurization, since, through the usual method of sterilization the destruction of all germs is not attained and the disadvantages are too apparent. The wholesale depots may be provided with outfits for bottle pasteurization and milk heating, in which flowing milk, through the influence of steam on heating surfaces may be brought to a temperature of 85 deg. C. In heating bottled milk it is essential to observe that the milk should become uniformly heated through- out; this is attained by shaking the milk during its pasteurization. Following this, rapid cooling should be undertaken, which is best accomplished by atomizing pipes which cause water to fall upon the hot bottles in the form of a spray. The apparatuses in which the milk flows over heated surfaces should be so constructed that all parts of the milk will come in contact with the heated surface, making the heating of the milk uniform in all parts. The utilization of the heat in some of the appliances is regulated in such a way that the cold inflowing milk is warmed by the outflowing pasteurized milk, the latter, however, being cooled subsequently. Through the exchange of heat from the outgoing stream of milk about one-half of the required heat may be saved. The efficiency of some of these apparatuses is enormous, since they are able to treat from 5000 to 8000 liters per hour. From a sanitary standpoint it is apparent that such appara- tuses must be so constructed that they may be readily cleaned mechanically, since improperly cleaned places conduct the heat poorly, and may give rise to contamination of the milk with putre- factive bacteria. In pasteurization, the same as in milk production, the greatest stress should be laid on immediate and thorough cooling, and on keeping the milk continuously cool until its consumption, since otherwise the pasteurized milk wil! become spoiled, and will un- dergo a form of decomposition which is very undesirable (espe- cially in bottle pasteurization). Pasteurized milk decomposes through multiplication of protein splitting, peptonizing bacteria whose spores may have withstood the heating. The vegetative bacteria, among these the lactic acid producers, are mostly de- stroyed, and except for a few resistant forms of spore bearers only heat-resisting organisms will remain viable, but these forms of bacteria are usually harmless (Rullmann, Gerber and Wieske, 196 Effect of Heat. Burri, Russell and Hastings). These germs decompose proteids and carbohydrates by forming butyric acid with gas production, and peptonizing the proteids. Boiled milk decomposes more read- ily than raw milk from the bacteria which contaminate it after the heating process. Relative to the effects of pasteurization, the following should be noted: Asa result of the effect of 85 deg. C. the bacterial num- ber dropped from 10,000,000 to 500 per e. ce. These remaining organisms however, which consist principally of peptonizing var- ieties, multiply rapidly to very great numbers if the milk is brought again to 25 degrees C., frequently producing changes in taste, which becomes bitter and irritating, but sometimes without mark- edly changing either the appearance or taste. This however does not render pasteurization hazardous, since it is possible through proper handling of the milk to prevent these undesirable processes. The marketing of pasteurized milk becomes dangerous only when.the consumer considers that pasteurized milk being free of germs may be kept indefinitely under almost any circumstances and therefore takes less care of pasteurized milk than he would of the raw product; besides this consumers repeatedly heat such milk and thereby diminish its nutritive value more and more. It is for this reason that various authorities have taken action against the indiscriminate distribution of pas- teurized milk. It should be required that the date of pasteuriza- tion be indicated on each bottle. A statement from the officials of the city of Leipsie asserts that pasteurized milk is not more valuable than raw milk, but that it appears to be of lesser value on account of the destruction of its raw condition and the consequent changes. Any manipulation of milk which claims to extend its keeping properties by several hours, and which possibly may be used in the establishment of false valuation by statements that the milk has a lasting, keeping quality and a freedom from bacteria, is directly dangerous and injurious to health if the consumer is not thoroughly informed with regard to the effectiveness and limitations of pasteurization. The action of peptonizing bacteria in milk that has been pasteurized is pointed out, and recommendation is made against the purchase of milk which was pasteurized more than three days previously. The official statement also calls attention to Barlow’s disease, and to the dangers attending improper keeping of such milk. Sometimes pasteurized milk which is never free of bacteria is marketed under the attractive declaration of ‘‘free from disease- bacteria.’’ What is the relation of pasteurization to such a elaim as this? According to the experiments of Forster, van Geuns, de Mann, Ringeling and Koning, de Jong, de Graaf, and Beck, the disease-producing bacteria are affected differently by high tem- peratures while in milk than when in bouillon or water. Thus for instance heating for a half hour at 70 deg. C. is not always sufficient to destroy colon bacteria. Tubercle bacilli are still more resistant. According to Kolle and Beck they are not destroyed with certainty even when subjected to heating for a half hour at 80 deg. C., especially not when they are isolated from the influence Thermal Death Point of Bacteria. 197 of the heat by the formation of a surface scum and by coagulation. De Jong concludes from his experiments (bottle sterilization) : 1. That heating for a half hour at 71-72 deg. C. is not always sufficient to destroy the tubercle bacilli mixed with the milk. 2. That heating even to a higher degree does not always give satisfactory results since the resisting power of the tubercle bacillus varies. 3. The designation ‘‘free from disease-bacteria’’ for pas- teurized milk is false. 4. Those who desire milk free from tubercle bacilli must purehase sterilized milk, provided it is not obtained from herds free from tuberculosis. Bang, de Mann and Forster obtained evidence that heating to 85 deg. C., for three minutes destroys the tuberele bacilli, a fact which has also been confirmed by the work of Weigmann and by the experiments of Tjaden, Koske and Her- tel under conditions which prevail in large distributing plants with milk from tuberculous udders. Other non-spore-containing dis- ease-producers in milk are also destroyed at this temperature pro- vided that certain conditions do not prevent proper heating. [According to the experiments of Rosenau, it is evident that the tubercle bacillus in milk loses its infective properties for guinea pigs when heated to 60° C. and maintained at that temperature for 20 minutes or to 65° C. for a much shorter time. It should be remembered that the milk in the tests of Rosenau was very heavily infected with virulent cultures, which was indicated by the prompt deaths of the control animals. Milk would practically never con- tain such an enormous amount of infection under natural condi- tions. Itis therefore justifiable to assume that if 60° C. for twenty minutes is sufficient to destroy the infectiveness of such milk when injected into the peritoneal cavity of a guinea pig, any ordinary market milk after such treatment would be safe for human use by the mouth as far as tubercle bacilli are concerned. These results are substantiated by the findings of Versin, Bonhoff, Th. Smith, Sehroeder, Russell and Hastings and Hesse. Relative to the thermal death point of other organisms Rose- nau found that typhoid bacilli are killed in milk when heated to 60° deg. C. and maintained at that temperature for two minutes. The great majority of these organisms are killed by the time the temperature reaches 59° C. and few survive to 60° C. The diphtheria bacillus suecumbs at comparatively low tem- peratures. Oftentimes it fails to grow after heating to 55° C. Some occasionally survive until the milk reaches 60° OC. The cholera vibrio is similar to the diphtheria bacillus so far as its thermal death point is concerned. It is usually destroyed when the milk reaches 55° C., only once did it survive to 60° C. under the conditions of the experiments. The dysentery bacillus is somewhat more resistant to: heat than the typhoid bacillus. It sometimes withstands heating at 198 _ Effect of Heat. 60° C. for five minutes. All are killed at 60° C. for ten minutes. However, the great majority of these micro-organisms are killed by the time the milk reaches 60° C. So far as can be judged from the meager evidence at hand, 60° C. for twenty minutes is more than sufficient to destroy the in- fective principle of Malta fever in milk. The Micrococcus meliten- sis is not destroyed at 55° C. for a short time; the great majority of these organisms die at 58°, and at 60° all are killed. Milk heated at 60° C. and maintained at that temperature for twenty minutes may therefore be considered safe so far as con- veying infection w ith the micro- organisms tested is concerned. ‘Ayers states that the best method of pasteurization at the present time, and the one which should be used, is the holder proc- ess, in which the milk is held for 30 minutes. For this process a temperature of 63° C. (145° F.) is to be advised, since that temper- ature gives a margin beyond that sufficient to destroy pathogenic organisms, while at the same time it leaves in the milk the maxi- mum number of lactic-acid-producing organisms which cause the souring of the milk. When using the flash process, the milk should be heated to at least 160° F’. Since there is almost always a fluctuation in the temperature during pasteurization, care should be taken to see that the temperature never drops below 71° C. (160° F’.) in the flash process.—Trans. | Exposure at 50 degrees of temperature for 15 minutes or at 70° C. for 10 minutes is sufficient to destroy the virus of foot-and- mouth disease. The virus is destroyed instantaneously at 85 deg. C. All of these advantages may also be obtained from subjecting the milk in the household to heating for a short time without poiling, when through occasional stirring the formation of the scum upon the surface is prevented. Therefore the purchase of raw milk, whose fresh condition can be readily controlled, should be generally recommended, and the destruction of bacteria should then be carried out by simple heating. The observation recorded by Schut appears to be worthy of consideration, namely that relatively low temperatures rapidly destroy bacteria, when applied simultaneously with a lowering of the pressure. In heating the milk at 70 deg. C. the disturbing scum formation was omitted. As accepted by Schut, in this process the steam penetrates into the body of bacteria, which explains the more efficient action of this method. Experiments which aim to improve the keeping qualities of milk by the addition of chemical substances are very numerous. In addition to improving its keeping qualities the retention of the raw condition of the milk was attempted. This does not refer to the adulterations which are undertaken by dealers for fraudulent purposes, or which are carried out in the household, and it should be considered that all additions to milk without subsequent decla- ration are equal to an adulteration of food, changing it to a spoiled product, possibly even converting it into material injurious to health. Preserving Milk with Chemicals. 199 At that the additions do not accomplish the purpose for which they are intended in the dilutions in which they are used (Richter- boracie acid), or they diminish the utilization of milk for cheese production because they inhibit the rennet action. Soda or bi-ear- bonate of soda, beracic acid and borax, more rarely salycilic acid, and recently formaldehyde are mostly used. Adulterations will not be discussed here, but only earnest scientific experiments will be taken up, in which the accomplishment of an actual improve- ment in milk has been the object sought. 1. Budde succeeded in improving the keeping qualities of milk with the aid of peroxide of hydrogen. The milk is heated to about 50 deg. C., 0.036 to 0.5% H;O, is added and it is then filled into bottles and kept for several hours at 50 deg. C. According to Lukin it is possible with pure peroxide of hydrogen, as indicated by Budde, to give the milk a low bacterial count, or render it free of bacteria. Budde’s method has not at- tained an extensive use. According to Chick, Rosam, Gordan, Bergmann and Hultmann, Hicholz, Nikoll and Duclaux the amount of peroxide of hydrogen recommended by Budde is not sufficient for the satisfactory destruction of bacteria in milk, but according to Lukin their failures were due to the use of impure preparations of peroxide of hydrogen. Tubercle bacilli and typhoid bacilli were not destroyed by this method. If the authors used 0.1% of peroxide of hydrogen, the necessary quantity to produce steriliza- tion, then the milk obtained a bitter taste, which disappeared only after the excess of hydrogen peroxide had been eliminated by cat- alase. According to Utz a small quantity of peroxide of hydrogen is retained in the milk even when used in the quantities recom- mended by Budde. De Waele, Sugg and Vandevelde, who worked with 0.3 and 0.4% of peroxide of hydrogen, have used in addi- tion small quantities of defibrinated blood for splitting up the retained H.O.. Much and Romer employ a similar method of preserving milk which has been obtained under special precautions as to cleanli- ness. The milk is filled into sterilized bottles, mixed with 0.1% of peroxide of hydrogen, and kept for one hour at 52 deg. C. — For the destruction of the H.O, in the milk, hepin, a catalase prepared from liver, is added to the milk before its consump- tion. Since the hydrogen peroxide milk is very sensitive against the influence of light (when exposed to light it very readily be- comes bitter, tallowy and rancid), it is best to keep it in green bottles and in a dark place. Even with these precautions a change in the taste may become apparent after two weeks. Injurious action of the peroxide of hydrogen if used in these quantities should not be feared; the results in infant feeding are supposed to be favorable. The milk which is freed from the retained peroxide of hydro- gen by the addition of hepin should be immediately used, since it 200 Effeet of Chemieals. is no longer resistant to decomposition through bacterial con- tamination, after the hepin has been added. 2. Years ago von Behring recommended the preservation of milk by formaldehyde. Experiments upon animals showed that the addition of formaldehyde to milk in the proportion of 1:1250 gave it no properties injurious to health by any method of appli- cation (even intravenously), and it was further found that animals with a very delicate sense of smell failed to recognize the presence of formaldehyde if it had been added to the milk in a dilution of 1:10,000. The action of formaldehyde in such dilution is quite marked. The addition of a 1:10,000 dilution postpones coagulation for many days (von Behring, Price and Schaps); 1:25,000 and 1:40,000 prevents coagulation from 1 to 4 days (Kolle). The action of formaldehyde was found to be more effective in accord- ance with the cleanliness of the natural milk and this action aec- cording to Rothschild and Metter appears to result from the fact that the lactic acid bacilli chiefly suecumb, whereas the other saprophytes are harmed to a lesser degree. Tubercle bacilli are not influenced in their viability by these dilutions. The feeding of infants for weeks with formalin milk (addi- tions of 1:25,000) may result in an injury of the kidney epithelinm of the children, which leads to the elimination of albumin.