>*-'- :sT"»'i.'c 'I Xibrar^ OF THE IRew l^orf? State IDeterinari? College AT Cornell IHnivetstt^ Cornell University Library SF 257.E71t Text book ot milk hygiene, 3 1924 001 096 894 Cornell University Library The original of this bool< is in the Cornell University Library. There are no known copyright restrictions in the United States on the use of the text. http://www.archive.org/details/cu31924001096894 TEXT BOOK OF MILK HYGIENE BY DR. WILLIAM ERNST Oflifial VrjliTinarian ajirt ]>ire'lor ot the Royal Milk Cnntmi .station at Munich AUTHORIZED TRANSLATION WITH ANNOTATIONS AND REVISIONS BY DR. JOHN R. MOIILER, A. M., V. M. D. Chief of Pathological I >i\ i.-^ion, I'nihil Statfs i;iir<;iii nf Animal InIo,i;ist, rathollication. We did not lose sight of the fact that it should meet with the conditions ]irevailing in this country and accordingly we Translator's Preface. have included mueli 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 For this reason Chapter X dealing with German laws and regulations has been replaced by Chapter XI which deals solely with the conditions and standards existing in this country.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 cannot 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 diiring the preparation of this volume. JOHN E. MOHLER, ADOLPH EICHHORN. Washington, D. C, July 1, 1914. Author's Preface & THE iiifvoasoc] importance of milk as himian food demands more and more t]]o 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 he laid upon production, which con- stitutes a special field of the milk industry, and -which is most generally in need of elevation and impi'ovcment. The product will lie without reproach only when the conditions of production correspond to the value of this food. In the tield of production, veterinarians are the proper ex- perts who must stand by the side of the produem-s and ,i;ive 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 tlie producers; provided, at the same time, other points of milk hygiene which possess bad features — in spite ef the active ])i'ogress 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 siibject. More s|»ecific questions, as for instance, the preparation of certain milk mixtures for the feeding of infants, the advantages and disadvan- tages of feeding ecnvs' milk to infants, the action of a milk diet in the treatment of adults, etc., are subjects for the physician. A 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 Avould 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 described 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 kno^vn works of my previous teacher. Professor Dr. med. Th. Kitt (Pathological Anatomy) and from Friedberger and Frohner's Methods of Chni- cal 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. ^Y. ERNST. Munich, January, 1913. Chapter I. ANATOMY, PATHOLOGY AND HISTOLOGY OF THE MAMMARY GLAND. Development and Gross Anatomical Structure. In the lowest form of mammalian lilV a .i;ioup of .ulandnlar (liK'ts becomes dilTerentiated from the glands of the skin in the median ahdonunal region. These (hiets exn(h' their hxcteal secre- tions ujion tufts of hair of the mammary region, from which it is either licked or sucked l)y the young (duckhill, ( (rnithorhynchus paradoxus). One of the land duckbills, the si)iny anteater (I-]chidna hy>- trix), has hicteal (hicts oi)ening witlun an abdominal iK)n( h formed by a fohl of skin of the maunnary region in the >liaiie of a ]iocket, in which the young are pidtected and nourished duriii:;' tiieir de\-elo]iment. "^I^his abdominal pouch is not identical with tiie tegnmentai-y wall from which is devehiped tlie teats of hii;her niamimils, but it nuiy be taken as the ])oint of origin of the dilTerent forms of teats. In higher marsupial aninuds the ghmdular ducts are united into a comph'X ghuid with teats whicli constitute tlie orilices of the confluent lacteal ducts. In other still higher species the most varied kinds of gland strTietures ai'e observed with various forms of teat development. .\mong the higher manunalian forms the evolution of the>e anatomical structures may he followed during embryonic life. On both si.les of the body, between the anterior limb-bud and the inguinal fold, the niijk-ridtje deveIo])S from a linear thiokeiiinjT of the citolils'-t in the form of a leilge- like elevation of the ejiidermis. Along this niilk-ridiie a series of at first spindle-shaped, then round enlar^'onicnts appear, whieh are separated by absorption of the intervening jiortioiis of the ridi,'!'. These enlargements t'on-ist of masses of epithelial cells, which C'lirrespond tii the aiilage, primonlium or point of origin of the true mammary gland of tlir lowest mammalia. This anlage sinks into the underlying mesoblastic tissue and 1 eioiiii's s'lrronnded by a proliferating integument, which forms an investment for the L;rcuviiig ejiithelial mass. From this mammary envelope which 1 ecomes more or less flat- tended the fibrous and muscular tissue of the areola and teat are derived. At its base, scdiil epithelial s|inints grow out from the siiles of the conical epidermal plug, later be- coming the lactif.-niiis .lucts, while the club-shaped thi.ki'iicd extremities in the further iiiiir^e of tlicir deM'ln|inirnt, form the milk sinus. SiilisiM|iii'iitly, the central part of the cctol hi^tii- iiigripwtli iinderL'oes dcLreiieration and what at first wa- an elevation, now be- 1 Anatomy, Pathology and Histology of the Mammary Gland. 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 (tiie milk duct), the end of which, the milk cistern, breaks up mto tlie 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, KoUiker, Langer, Bonnet, Profe, Schwalbe, Huss, Gegenbauer, Klaatsch.) According to the number of the glandular organs there are disting-uished 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 s;s'Tnmetrically. 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 maramarum) 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 ai'tificial 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 cm. 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 escutcheon 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 duct. 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 pudic 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 subcutaneous 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 Ijaiiph vessels ^vhich are very numerous enter two large lymph glands -which lie bilaterally in a depression at the posterio- snperior portion of the udder and are known as the supramam- niary lymph glands. The lympli passes thence to the lumbar glands and into the thoracic duct. The nei'ves originate from the lumbar plexus. The udder is supplied by the internal branch of the ilio-hypogastric neiwe, the external branch of tlie 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 al)dominal 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 whicli are of importance from a practical standpoint, the inflannnations and chaniics which have more or h'ss influence on the quality of the milk are of special in- terest. The other anomabes will be mentidued only briefly. Not infrequently there may be present in cows siii)ermunerary teats, or suix'rnnmerary milk glands, which may lie considered as a reversion to early stages in the evolution of cattl(\ Usually two rudinieiitary formations occur which are generally situated heliind the posterior noinial glands and normal teats. These may at times yield milk (Burkart, Dauberton). TIk^sc accessory glands may also occur between the normal teats. In sevc^ral instances as many as four supernumerary teats were observed. If the udder is al»normally 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 %nthout secretion, is most conspicuous in male animals. Pusch ob- sei-ved a buck which produced 70 g-m. of colostrum-like milk daily, and which possessed nipples 7 to 9 cm. in length. Gurlt has re- ported that the udder of a steer was as strongly developed as in a cow, and produced daily l^^ liters of secretion. It is known that newly born kids and suckling colts occasion- ally secrete milk for several days (Gurlt, ]\rartin, Hess. Ibel). Schmidt, of Dresden, reported a giant udder with an entirely Anatomy, Pathology and Histology of the Mammary Gland. normal milk secretion, (16 liters). A functional hyperemia in the beginning of the lactation period increased the four quarteis uniformly to such an extent that a day after parturition the udaer touched the .ground with its central surfaces. -p i, . Before and after parturition an abnormal amount oi 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 manifePts 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- fections of wounds with the bacillus of malignant edema may result in edema of the udder. 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 liy way of the blood circulation 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 l)acteria, and is not caused bv one kind alone, the affection is a mixed infection. The infection inav result from traumatic conditions when injuries extending into the paren- cb;smia of the ghmds make the infection possible, or from o-alactif- erous-traumatic causes when the infectious material enters tlie 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 mav arise, depending upon the character of the infectious material and upon special accessory conditions. The possibility of galactiferous infection was first experimentally nrovp,, 1,^ t? i The character and the varieties of inflammations of the udder were fuXr Js7«M- ? ^ by he work of Kitt, Nocard and Mollereau, Lucet, Bang, Hess and Bor"eaud r m f ^"^ Zscliokke, Sven Wall, and others. "oi.,eau,l, Gmllebeau, ratholoiiicnl Anatomy of tlie Tdder. The principal prodiieers of mastitis are the colon-paratyphoid group, stajihylococci, .str(^ptococci, JJ/iciUus pijof/eues hovis, Bacillus tuhcnntlnsis, and the actinoinyecs. Colon infection and severe mixed infections nsnally resnlt from galactifcrons contact, or after the introduction of milking- tuhcs, straws, qnills, cat-gTits, and hairpins. Highly acute, inflam- matory conditions develop in the affected quarters, whether af- fected throughout or only partially with parf■ncln^natous mas- titis. Hot, painful swellings of the ciuarters, with collateral edema Fiir. 1. Atnite iiirlamiiuition of tlie riirlit fnro(|uarter with collateral edema (Alter Kitt.) 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 cpithelia destroyed by the disease or on the other hand the di- sease becomes chronic and may ev( n terminate with complete gan- grenous and ichorous destruction of the affected part of the udder. fi-t ' In tlie iiilV. tions forii;s lastitis tlie siniraiiiaiiiiuary lymph glands mav swell to li the process becomes chronic a suppurative softening of the affected \K\\\> of the tissue, or a suppurative demarcation of ne- crotic ])arts of the tissue results. These contlitions are designatei.l 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 elin- Fig. 2. Fibrinous form of parenchymatous mastitis; separation of quarters plainly visible. (After Kitt.) ical examination may cause a suspicion, but a positive diagnosis cannot always be established. Literature shows that slightly marked swelling of the affected quarters, mcreased local temperature, nodular formation of the parenchyma, and induration of the glandular tissue, may appear m 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 l)e neglected The mucous membrane of the cistern may have become iiiflamed" Pathological Anatomy of the Udder. 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. Fijr. 3. Purulent matititis showini; 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 liy the pro- liferating connective tissue causing the quarter to atrophy and harden. Tubei'culosis although almost invariably resulting from a hematogenous infection, appears either in the form of a single focus (tuberculosis uberis circumscripta), or it may be dissemi- nated over the entire ])arencliynui (tuberculosis embolica dissem- inata), or tiie ti>suc may be diffusely alVccted. 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 m the same udder. During the tuberculous invasion nodular mdurations ot 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 m tu- berculosis of the udder. Actinomycosis which commonly develops from the penetration of actinomycotic 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- omyees 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. Botryomycosis 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 libroma, adenoma, adenofibroma, adenocarcinoma, chondrofibroma, chon- droma, lipoma, sarcoma, angioma, etc., which are dependent on the tissue elements and the character of the tissues of which they are composed. Cystic formations have also been observed. Not infrequently the connective tissue and the subcutis 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, A'oh 1, page 2S0. 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 papillae, are extraordinarilv 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 demarcation, with tbe mucous mem- l)rane of the milk cistern, wliich is covered by several lavers of cylindrical 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 anct elastic encasement around the canal of the teats. The supporting structure is penetrated by numerous blood structure of the Tiisue. 9 vessels and lympli vessels. Numerous and strong elastic £11 ires strengtlien the dense fibrillar connective tissue of the teats. In order to describe the finer structure of the parenchjina of the udder it is necessary at first to touch on the further develop- ment of the ori;an from birth until the moment of the appearance of the secretion. (a) Xoniial Appeaiance. The milk ,i;huid is an organ ■which ]ierf()rms increased func- tions only at certain times. It does not secrete during the entire Fi'i. 4. ^^^^^iv^ .'/,! ''^^^^{k Vritii-;il section throui;Ii the lower end of the teat canal which is closed by a horny plug fa). 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 ]iart of the lobule may be found on examination, de|)ending whetlier the cell coinplex is just fonning the secretion or has al- ready di>('harged its secreted product. The gland of a newly born calf shows b'lt relatively few cell tubes ami cell bmls, inibcMcil in lonnective ti^^iu' rich in fat ami branching in all direction's. The^e prac- tically form the basi-; of tlic glandular diirts ami arc without alveoli. The end of the till rs is frcuueiitlv -.(inu'what 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. 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 duets is of double layers, as m 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 Strufture of the Tissue. H should be considered, according to tlie 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. Fi.'. 6. % \ structure nf the mammary gland in secretion, Hematoxylin. 1 X Snn. (a) Stcreiing glandular alveoli, (b) Alveoli with dormant cells. At the end of pregnancy the picture again changes consid- eral)ly. The protoplasm of tiie previously clear epithelial cells of the secretory system becomes cloudy, the nuclei larger, their chro- matin collects in Hakes on the periphery of the nuclei, the borders of thi' 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- lial cells show two nuclei at this stage; towards the alveoli fat globules ajipear. Leucocytes with which a few eosinophiles are mixe(|, 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- Fig. 7. mwm Chronic mastitis of cow. 1 X 800 n^ v-X ^'',"=l«"«'l interstitial tissue. (b) Alveoli. (c) Blood vessels. (1) Epitheial (les,|Ui,mation. (2) Colostral bodies. (3) Cellular infiltration. (i) iatty 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 runnmg m 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 nf the Ti^^sue. 13 into lai'sor 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 lyiiiH' towards the lumen appears indistinctly bordered as if sli redded after the expulsion of the fat. They soon become smooth ai;ain, and by the pressure of the alveolar contents and the dilation Fi'^. 8. C'ironic mastitis nf cow. 1 X 9'^. (al Il.'altliy portion. (b) Glandular portion with chronic mastitis. of the alvtmli. +he cells sink and become so flat that the nuclei not inrre(|uently appear bulged out towards the lumen. After the expulsion of the secretiiui the formation of additional .secretion ai^ain (•(niniieiices in the cell, the protoplasm aijain becomes cloudy and granular, and so on, a continuous change of the form of the cell takim;- ]ilace. Dui-ini^- the entire lactation period, but more ^o in the later staiies, manifestations of atro]iliy nf the yland a]i]iear, at lir-t 14 Anatomy, Pathology and Histology of tlie 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 Fig. 9. Acute streptococcic mastitis of sheep. 1 X 1000 (a-1) Blood capillaries. 2. ThromlDosis by disseminated streptococci, (b) Glandular alYOoh, 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- iorm 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, leucocytio resorption activity and connective tissue proliferation cause them to cease their activity. (h) Pathological Appearance. ^Vny 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 I'eeovery gain the predominance. Sometimes desquamation of epithelium, with or without fatty degeiiei'ation, oeeurs together with cellular infiltration of the in- terstitial coniieetive tissue and capillary engoi'gement as the only indications of inflammation; or, on the other lumd, the changes in the interstitial parts may he veiy pronounced, while the chaiii;es of the pai-eiiehyiiia may l)e less pi'omiuent. Tlie inter- and intra- lobular comieetive tissue extends forming thick indurations, from which the sejjarated epithelium is compressed to small neerotie 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 dilate(l with the pus. In liigiily 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 inundateil 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- crement arranged in layers, in addition to inflammatory cells and broken down cellular products. Chaptee 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, etc., bv Eckhardt, Rohrig, Sinety, Busch, Mirnow, Pfister, Eibbert, 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 thev mav be led to exert their action either by the quantity or by the qualitv of the blood. After parturition the body and the milk gland luive 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. of its gTowth througli nervous influences. On the other hand it has been ohscrvod 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. Asa matter of fact the secretion may commence before birth, and even in early abortions, oi- if the fetus dies. At times Avhen the uterus is only so slightly distended that the quantity of blood set fi-ee after abortion is hardly sufficient for an effective hypere- mia of the milk gland, the secretion of milk may result (Sinety, Krcidl, ^landl). Therefore the explanation that the quantitative influences of the blood may give rise to a stimulation of the milk seci'ction (Freund), can scarcely be accepted. Consequently the qualitative changes of the blood must be considereil as more prob- able factors. ^Vuthors have diversifleil opinions upon this question. While some accejjt tlie view that substances are eliminated from the inqiregnated organs, or by tlie fetus itself into the blood of the mother by internal seci'elions, and that these act as stimu- lants on the milk glaiuls, others believe that the factors causing lactation lie in the assimilation of cei-tain nutritive substances. The supporters of the theories of ''stinudation substances" (Sinety, TTalban, Starling) take the stand that stimulating sub- stances which cannot be utilized for the cellular gi'owth and cellu- lar activity, contrai'y lo ilie nutritive substances, cause tlie (h'vel- opment of the gland during ])regnaiic>', and at the same time pre- vent it from secreting (stimulines, hornioiies fl stinudate], sub- stances of pregnancy). Develoitment of the gland and prevention of secretion may, of course, be the action of one and the sam<' sub- stance (Hildebrand, Starling), or its develo])ment, as long as the growth continues, may retard secretion. AVitli birth the stimula- tion of growth and develo]nnent ceases, and secretion coumiences. Contrary to this, the theories of nutritiv(> substances empha- n'w.c the fact that the glands at times may start the si^ecitic activity without the presence of certain stimulines. probably through nutri- ti\-e 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 nmterial liecomes available, which has served prior to birth for the jireparation of nutriment for th(> offspring. While the ex- l)lauation of the author that the hnnph 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 1!10S by Schein by the state- ment that during preyiiancv the mother animal, in order to meet the i-e(|uiremeiits of the fetus and of the impregnated organs, en- 2 18 Physiology of Lactation and Characteristics of Milk in General. riches lier blood witli the so-called "milk producing substances." Pfaundler recommends the designation "offspring nutritive pro- ducing substances." Since during pregnancy the contmuously developing placenta utilizes and consumes these substances for use in the nourishment of the young, there remain for the milk gland only slight 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 gland 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. Schein'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 com.petition 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. Eievel 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 sulistaneos" enter without clianging directly into tlie 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 mammfe, or in milk glands of individuals which have passed their climacteric, 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 stinuilants may under certain conditions stimulate the activity of the gland. Duval's more recent observations contain data relative to the occurrence of milk secretion l)y women outside of their normal lactation periods. It is not uncommon to observe secretions in virgin aninuils especially when young animals which are pi-esent stimulate the udder intensively by sucking. It should be emphasize(l however that the udder secretion of virgin animals distinguishes itself in its appearance from the milk of mature milking aninmls; it repre- sents a seci-etion which does not even deserve tlie name of milk. The experiments which were ('(Uiducted by varinns authors in support of their lactation theories ajijiear of interest. The experiments of Starling aim to show the presence of bodies in the blood during ]iregnaney which prevent se(Tetion, in which claim is nmde that an interruption of ]u-egnancy in rabbits at a time in which alveoli callable of secretion were not yet ]iresent, led to a retrogression of the milk gland, while in the later periods of in-eii'nancv secretion was induced. According to Pfaundler's view the hanuone theory could be effectiv<'lv 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 nuuitions observations made in a case in which the secretion ap- peare(l at birth of twins which were born at long intervals, that is, tlie i)regnancv continued after the iirst birth, yet the milk secretion continued unchecked. Wucherer observed a case in which a soav <.ave birth io nine, ar.d seventeen days later to six other pigs. At tl'ie birth of the second lot the first born pigs were taken from the s,nv The^e continued to thrive, but of the second lot only three renmined alive. He emphasizes the opinion that a transitory 20 Physiology of Lactation and Characteristics of Milk in General. action of blood serum, as used in Pfaundler's experiment, which corresponds only slightly in its composition with the normal blood serum, can never be favorably compared with natural influences in the l:iody. 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 chemical changes which are produced by the growing embryo and are brought to the glands through the placental circulation. Ac- cording to Basch, secretion may be established in the mammary glands of virgin rabbits by injecting them with placental extract (serum of unhke origin, from man), which was so powerful that it also brought on a secretion of milk in mother animals without the intervention of preg-nancy. The placental extract could induce the secretion only when the teats of these animals were stimulated to hyperplasia by the implantation of ovaries from pregnant animals. According to the author's observations these questions can only be determined through experimentation, when by uniting two female individuals of like species a basic condition is established, by which the activity of the glands of one of the impregnated indi- viduals as a consequence of its pregnancy may be observed upon the other, and the result of the impregnation of the latter on the lactation of the first mother may also be determined. Such experi- ments have already been made by Oristea of Vienna, l)y coliotomy of a virgin and a pregnant animal, and uniting both by "suturing of the peritoneum, the musculature and the skin, the author establish- ing a double individual, united by a broad peritoneal communica- tion. Of eighteen such pairs (rats and rabbits) six remained alive. In the experiments after parturition of the gravid animals the milk secretion also appeared in the virgin animals to which they Avere united. Cristea therefore believes in a slow transition of a secretion from the gravid animal into the non-impregnated animal, namely by the way of the lymphatics, since there existed no blood vessel union between the individual animals. With this result the hypoth- esis that the changed distribution of the blood after birth pro- duces the milk secretion collapses, since on account of the lack of communication of the blood vessels it is not possible that an in- creased blood supply of the mamnife of the virgin animal would result from parturition of the attached animal." It can make no difference whether milk producing substances or substances which are not assimilable and are not consiuners of energy (stimulating and inhibiting substances), stimulate the glands to activity. Eecently Basch observed an abnormal birth to one of a pair of twins (the Blazek sisters showing a condition of pygopagus, union of the pelvis and sacrum with a common introitusvaginEe ' and a common rectum), in which after the birth of a child to one, lacta- Milk Secretion. tion commenced also in the vii'gin sister. In this instance nervous connections may exist in the genitals of both individtials. Accord- ing to the author's view this case is not an absolute proof of the stimulation of the gland by hematogenic means. The lactation theories may be laid aside, and consideration only be giveii to the fact that at birth, puberty, preg-naney, at the conclusion of parturition and also in the disturbances of the gen- itals influences are exerted on the milk gland the character and action of which are still uncertain, although the results manifested liy the production of milk may readily be observed. Especially t}7)ical and striking are the phenomena seen at puberty and during and at the end of pregnancy. Exceptionally a condition may ap- pear outside of these normal periods of the organs in females, and in single cases even in male individuals, which permits the conclu- sion that tlie glands react to special stimulation. Abnormalities may occur in tlie anatomical structure of the gland, pathological manifestations in the sense of inflammatory rcaftions, etc., may also be observed, and exceptionally the usual functions may be present or may develop, without their being accompanied by gross anatomical changes of the gland; these however aic usually ])i-es- ent at the same time. Tliese influences on the gland originate partially in the gravid genital organs and the fetus; in other instances the genninal glands and the disturbances of their functions are tlie cause of tliese influences. Such influences may be classed according to tlie impulses which lead to glandular activity, as follows (TTaliian) : 1. Emiiryonic impulse — action very transitory — mastitis neonatorum — witches milk. 2. Puberty — lasting effect — development of the gland. 3. Oestrum — action rapidly transitory — In-peremia, inter- stitial hemorrhages, disturbances to physiological lactation, secre- tion. 4. Impulse of pregnancy — lasting between parturitions. Lactation may be sustained for a long period of time by the regular drawing of the milk, and ceases in healthy udders only when after frequent and absolute stasis of the milk (after about eight days), the tissue becomes affected by inflammatory irrita- tions (afisorbtion and change of the condition of the epithelium), or when the animals are soon to give birth to young. If no re-im- pregnation takes place the lactation period may last longer, even from one to two years although not to an unlimited extent. The activitv of the ghind may be retained for a long time through the sucking of the young, stimulation hy milking, or artifical with- drawal of milk. Frequent periodical and complete emptying of the milk cis- terns acts favorably on the amount produced. In the cow two to threi" milkings per day are sufficient to retain the udder in secretion. 22 Physiology of Lactation and Characteristics of Milk in General. The milk formation occurs between tlie milking periods and during the milkings ; therefore of these two periods, the first lasts for many hours, the second with more intensive production is com- pleted in a few minutes. The first phase is the Avork of continued activity of the gland, the second is brought on under the stimula- tion of the sucking, or milking, on the secretory nerves, and as a result of the increased blood supply (stimulation of the vasodila- tors). The capacity of all the milk ducts of the udder represents less than half of the quantity of milk obtained in one milking. According to Fleischmann the volume of the entire udder of a cow with the teats is 6700 c. c. Of this 3000 c. c. is represented by the cavities ; the secretion obtained in one milking may never- theless amount to 7000 c. e. Niiesch substantiates Fleischmann 's statements by an experi- ment; a cow gave daily before slaughter 10 liters of milk of which 5 . 5 liters was the amount of the morning milking'. After slaughter before milking in the morning 2.7 liters of milk could be proven in the udder (catheterization and calculation of the amount remaining in the udder), which proves secretion during the process of milking. The two phases may be considered as though the glandular cells which tire after the milking gradually recover (increased blood supply) and recommence their secretions. The collecting secretion will increase until a certain relative pressure between the collective quantity of secretion and the tissue with the blood vessels is established, when the secretion is retarded or ceases until renewed stimulation of the glands by milking, emptying, massage, (electric irritation), or stimulation of the central nervous system from milk accumulations causes the milk to fill the cavities of the udder again. If the usual milking time is omitted a flow of milk may result, that is the pressure under which the secretion is held finally over- powers the resistance of the sphincter muscles at the opening of the teats (directly or by reflex), whereupon formation of milk again takes place. ^Nervous influences on the secretion are exerted by the sper- maticus externus and by the sympathicus. _ Experiments which were conducted for the study of the ener- vating influences on the secretion produced contradictory results. Eohrig severed the ramus inferior of the nervus spermaticus externus (vessel branch), and observed an acceleration of the secretion, while the severing of the glandular branch (part of the median branch) resulted in inhibition. Eckhard failed to observe any influence on the quantity of milk after the severing of the ner- vus spermaticus externus. Heidenheim and Partsch demonstrated an increase of the quantity of milk from the cutting of the nervus spermaticus externus, but only when strychnine or curare had been administered at the same time (test by Sinety on guinea pigs). !^^ilk Secretion. Although Basoh could not establish a quantitative increase by sev- ering the nervus spermaticus externus, he found qualitative changes (formation of colostrum). Pfaundler concludes from these and other experiments that an action of the peripheral nerves on the development of the gland and its functions, especially from a qualitative point of view, must figure in the consideration, but that these influences have only slight importaufo. Insignificant as "well in their results on the secretion were the severing and re-sectioning of the spinal cord, or interference with the sjanpathetic sj'stem. Basch again observed the formation of oolostral milk after re-sectioning of the coeliae ganglion. From this he coiif'ludcs that the regTilating influence of the nervous system exists through reflex action, espeeially from the s}^npa- thctic, but that at the same time the gland is also capable of independent secretion. As a matter of fact far reaching influences of a nervous character are observed. 1. Psychic influences. 2. Reflexes, which are caused by local stimulations (sucking — milking — electrical stimulations, etc.). ;!. Keflcxes from the genital region. Tliese points are only briefly mentioned here, since the varioa ■; conditions will be discussed in sulise(|uent chapters, wlien considci- afion Avill lie given to the quantitative and qnalitaiiv(^ changes which appear under varying infhiences. An active pari in the emptying of the milk from the cisterns, and in the passage from the iipper part of tlie duct and alveolar sys- tems, is played by the sucking and pressure exerted during the milking (pressing outwards, sucking from the gland), massai;e of the udder (pressing out into the cistern), the contractility of the tissue (elastic fl))res, involuntary musciilature, filling of the blood vessels), and the vis a tergo of the newly formed secretion. Chapter III. MICROSCOPY OF MILK IN GENERAL. If milk is examined through, a microscope one chiefly sees numerous small fat cells floating in the fluid or milk plasma. These will be considered later, but at first the cells and cell fragments originating from healthy and affected udders will be discussed. Between the milk globules, by which term the small fat droplets are designated, bodies may be seen which are hard to define unless stained. After special treatment, however, they may be readily recognized as cells or their fragments, or as a precipitation of soluble or suspended substances. Since the external skin of the udder, and the lining of the milk passages and milk secretory ducts in the udder are of similar for- mation, we naturally are only concerned with the upper layers of pavement epithelium, cylindrical epithelium, and the deeper cubical epithelium of the terminal ducts and alveoli, and only in severe tissue changes would cells of other parenchymatous parts appear in the milk. Naturally in such an actively working organ, even in a physiological normal condition, leucocytes of the most varied kind, and even red blood corpuscles may be found. In cases of special stimulation from physiological or pathological causes, the resulting cell mixture may be of a most varied character depending upon the location of the stimulation, and its quality and duration ; hence at times certain leucocytes, and again red blood cells or epithelia, may predominate in the mixture. 1. Cells from compound pavement epithelium. Following the intensive manipulation and stimulation of the teats by milking, the appearance of cells from the upper layers of the pavement epithelium of the outer skin, and the milk 'ducts is natural. As a matter of fact in the fresh milking periods during which irrita- tion from the extraction of the milk is especially evident, the milk always contains fine folded platelets of round, oval, or irreg- ularly distended and curved borders, which frequently when folded in several layers, appear as small clasped cvsts without special structure. These bodies have been described by Winkler, and were con- sidered by him as indications of pathological changes. The author 24 Cellular Content of Milk. Fig. 10. took a stand against tliis view of "Winkler, as he had obserred them in the milk of entirely healthy animals, but not until the present time has he been able to offer an explanation of the nature of these bodies, designated as "skinlets" or "shell." They represent desquamated cells of the stratum mortifieatum of the pavement epithelial layers singly or in groups. Although usually no parti- cular structure is manifested yet in single instances tj'pical flat, round nuclei can be seen. If the teats of a slaughtered cow are taken and the cistern and milk duct are carefully cut open, and from the surface of the milk duct a small quantity of the cellular layer is scraped (I If, an examination by the usual metliod discloses the typical "shells." 2. If cells from the cistern are prepared and examined, elongated or oval, or quadrangTilar cells with oval nuclei, fre(|iient- ly elongated at the base, will be found, singly or in groups. Single fat drop- lets may frequently be seen in the plasma sur- rounding these cells. Sim- ilar cells may also be found in normal milk. They are usually single, although s m e t i m e s united in groups arranged like flow- ers. In stinmlation, which brings on a desquamation from the mucous mem- brane of the cisterns, or from the parenchyma in catarrhal conditions of the milk passages, they of course appear in masses. Such reactions occur in the cistern for instance as a result of the so-called kneading. 3. CV'lls from the secreting milk ducts and the alveoli, ap- pearing large or small according to the quantity of fat globules collected in them, often become tremendously distended and bloated (foam cells). Their structure is mostly honeycomlied or mulber- ry-sliaped when tliev contain fat ; without fat the cell is surrounded with only a narrow" border of protoplasm. The micleus is usually in yood condition. Film of sediment from milk of a fresh milking cow. Cells from the stratified laver of pavement epithelia of the teat canal. Thionin. 1 X 1000. 26 Microscopy of Milk in General. These cells are the large colostral bodies. They are in their entire structure and in their staining characteristic epithelial cells and not leucocytes ; the amoeboid movements observed in them, if these observations were beyond questioning, do not prove that all colostral bodies represent leucocytes. This point will be again taken up during the discussion of colos- trum. While such cells only appear occasionally in ripe milk they are extremely numerous at the beginning and termination of secre- tion, and in pathological processes, in the latter especially in sub- acute and chronic forms, but not in peracute and acute inflammatory conditions of the paren- '^' ■ chyma. Such cells may occasionally be noted collected in groups. The author believes that their appearance in masses in the milk, that is, the condition increas- ing the expulsion of these epithelia, results from the fact that each cell, which in its singu- lar activity precedes or follows the other cells of the union, becomes desquamated. It does not correspond func- tionally, with the other cells, and is therefore removed from the rows of cells which are de- veloping for a definite purpose or are working for that purpose. Only when uniform work is performed by all of the cells working in unison, , .. .... .„ ^, and bringing about a uniform condition, aviU the organ cease to free itself of incapable elements. In inflammation the inflammatory irritation and its consequences soon drive the cells to overproduction At other times it paralyses or destroys them, even before the formation of milk, depending on the duration of the inflammation , , "Tj^l !^™\^^ ^^If epithelium varies in accordance with the con- tent of fat. The collection of fat is not the result of f attv deo-enera tion, but IS produced when the cell is thrown off before 'its tune for secretion, or while still capable of taking up material and produc- ing fat but without strength for the separation of fat. Therefore Cells from the lining membrane of the wall of the cistern. Sediment in catarrh of the cistern. Thionin. 1 X 1000. * Cellular Content of Milk. Fiff. 12. such cells may be found even in the epithelial groups, which is an additional proof that they -with certainty represent epithelial cells. The cells are from 5 to 25, even to 47 h in size (Schulz). Not infrequently 2 to 3 nuclei of oval or roundish shape are present. The author has never observed more than one nucleus, and be- lieves, with Popper and Schulz, that the appearance of more than one nucleus results from two cells lying on each other, in which case the cell thus formed may appear to possess two or more nuclei. ]\Iigrated macrophages may also simulate a polynuclear appearance. Not infrequently epi- thelial cells are thrown off, with a single larnc fat globule in the body of the cell, known as "seal-ring cells." In such cases the fat glob- ules have a "moon" or "cap" ap])earance. 4. Leucocytes of all forms are frequently met with in milk su(4i as mononuclear basophiles, e()sin()])liiles, polynuclear basophiles, acidophiles, or c(4Is with neutrophilic and eosinophilic granules in the ]irotoi)lasni. If the polynuclear cells show no nuclear bridges, they may be found with •; /i or more spherical shaped nuclear granules (spherical gran- ule polynuclear leuco- cytes, Babs.) The nu- cleus is usually in the shape of a ribbon, or clover leaf, or heartshaped. The protopla>iii usually contains fat globules, which in stained prej)arations appear as fine vacuoles. The lymphocytes are small cells with round nuclei and a very snndl border of protoplasm. According to Schulz they never con- tain fat. Large mononuclear leucocytes are also sullllO:^ed to be ])res('iit in the milk. If they gorge themselves Avith fat they are lilied to their fullest extent, and can no longer be distinguished from fat-containiiii;- ei^ithelial cells. ."). The red blood cells may be seen as small, round or thorn- Scdiment in milk of a cow after milk stasis. Numer- ous desquamated epithelia, amon^ these an "albu- minopliore, " and polynuclear leucocytes. 28 Microscopy of Milk in General. apple shaped bodies, with, metachromatic staining substances. They may be readily recognized as erythrocytes. 6. Degeneration of these various kinds of cells may result in the finding of the most peculiar formations. The protoplasm of the epithelial cells becomes shredded; the nucleus splits up and eliminates its chromatin into the plasma in the form of dust or flakes. It diffusely passes into the cell pro- toplasm, which appears darkly stained, and in the place of the Fiff. 13. y^. Joi The formation of large colostral spheres and desquamation of "seal-ring cells." 1 X 800. nucleus a pale vacuole appears. If the breaking down continues there may appear a disintegration of the cell and of its nucleus into small droplets and fragments of roundish appearance, either with or without a lightly stained border around a small darkly stained center of chromatm (Heidenheim, Cohn, Popper, Schulz). These chromatin flakes are probably identical with the so-called free nuclei (Michaelis), which were also observed by Lenfers. The flakes which result from chromatoly'sis have been des- relliilar Content of :\Iilk. 29 i,i;-iiated up to the present as "Xisscu'.s Globules." According to f)dies and establish in the more and nioi'e distending cell actual lacuna>, in Avhich the de- vouring leucocytes lie. The remains of the pi'o- toplasm and of the cell and nuclear membranes tloat in the sliayx' of eaps and moons in tlie milk ])i'()to]»hism until the swelling or further lireiddug down con\'ei1s them into si)heres oi- globules. ^\t the sanu' time of coui-se the mac- I'ocytes may t h e m seK'es degenerate in iho eell, and no longer pre- sent a recognizable nu- eleus. In such cases its re>])ective lacmui con- tains homogeneous, sharply circumscribed pi'nteid ghd)ules. Tlii> author con-iiiicr'^ tlii-so epithelial t'olh Avliiih have been destroyeil by macro- ]ilia;,'i'v, as iilcntiral with the albuminophores of Bab ami s-hulz whirh thev de^^rrile'l ,■1'; laiL^e lyniiilioi-.vtcs. i l.l to -"n), containing fat ami 1 to 4 or more proteiJ globules. Budding irlnlMiIos, free nuclei. Xissen's globules, that is cl'U I'raLrnu'iits. in the sediment of co\v'& milk. 1 X 1000. Presides these regularly formed constituents of the milk, its se(liment contains flaky constituents, small irregular shaped eoag- uia, wliich readily tinge with basic anilin dyes, or with nuclear staining substances. Freiiuently they are without any structure. At times they a]»pear in individual milkinus, almost completely dominating the micro-'copical field. They are the early stages of the corpora amylacea, soon to be descrihed, which appear either 30 Mioroscopy of Milk in General. round, oval, bean-shaped, or nodular, ranging from very small (1 to 2 m), to an enormous size (5 to 200 ^ according to Zimmer- mann). These bodies show no concentric formation, _ or radial stripes. They usually appear during abnormal activity of the gland, and are found in colostrum, in stasis of the milk, in mastitis, in the inactive glands of older animals, etc. Their varied thickness makes active turning of the micrometer screw necessary. These corpora amylacea (according to Siegert, Corp. flava in contra-distinction from Corp. versicolorata, are the same as amylacea) were seen by Herz, OttolengM, Iwanoff, and later described by Martin, Lenfers, "Winkler and Zimmermann. Wederhake Fiff. 15. Epitlielia in different stages of destruction "by macrocytes, that is so-called albuminophores. 1 X 1000. confirmed their occurrence in the colostrum of women, and compared them with the corp. amylacea of the prostate gland. A section offers the best opportunity for the microscopical study of the nature of these bodies. In preparations of acute mastitis, their development is especially clear. Aroimd small flakes of proteids, possibly precipitated nuclear or cell fragments, layer after layer will be formed until a concrement results, which may oven fill the entire alveolus. Lime and salts of magnesium are later absorbed liy this basic structure of concentric layers and tine Milk Concrements. 31 radiated stripes appear upon its surface in consequence (Fi«-. 1.1, Fig. 16 and Table I.). While the alveolar epithelium succumbs to the pressure of the growing eoncrement, and may be ali^oibed for j-oine time, the eoncrement resists the influences of the organs, and finally is surrounded by connective tissue. Ziramermann states that the bodies may be either in the alveolus or on or under the epithelial layer, and even free in the con- nective tissue. These observations have been confirmed by the author. Tlioy stain with metliyloiK' blue, iodine green, and gentian violet, similar to other amyloid substances, but do not give the starch reaction w i t h indine solution and sul- Fig. 16. pliuric acid (Zimnier- numn, and author's ob- s('i-\'ati(iiis). Wedei-hake and Winkle 1- claim to have ol)taiiied a bluisli \'iolet coloration with iodine. The corpora amy- lacea of tlie mammary ,i;laiids resist few acids (sulphuric acid, hydro- chloric acid). ( )tto- lenghi and Zimniermann olttained a sohition with pure sulphuric acid. Tliey are therefore pure coiierenients of se- cr(>tion which form un- der peculiar conditions. T h e i r fjuality varies, depending on the char- acter of the precii»ita- tious, M'liich combine to lorm tliem. Lia^e eoncrement in the milk sediment of a cow. 1 X lOlll). What remarkable sionificance may be attached to such conditions may be indicated by the views of Herz, who considers thoni as the initial formation of casein, and tho-e by Winkler, who belio\i-'s that they change into fat or that they are degenerated epithelium. Leucocytes also crowd upon these bodies, and attempt to dis- solve them just as ostei)eIasts attack bones. Under their influence, combined with that of the liody juices, a destruction, solution and absorption of the concrements may take place, or on the other hand new layers of thickened secretion may form around the old deliris, and a new eoncrement develops. This describees, with the exception of the fat globules, the cell elements which may be demonstrated under the microscope, as far as they oiii^iiiate from the udder of the cow. The fat globules will be discussed i;nder the headinii' of juilk fat. 1^ v,^^ ^\ — ' ^i i *^* '•* (si J ■a; .^'' ■0^ # Chapter TV. COMPOSITION OF MILK AND ITS BIOLOGICAL, CHEMICAL AND PHYSICAL CHARACTERISTICS. There is very little known ■\vitli absolute certainty relative to tlie development of the individual constituents of milk. The theories in this regard are almost entirely hypothetical. It is certain that milk constitutes the s]3ecific product of cell activity of the glandular parenchyma, and does not represent a simple trans- udation of the constituents of blood, with a mixture of broken down products of cells (nuclear masses of leucocytes and epithelia, and fatty detritus), nor the fatty breaking down of the epithelium (Eeinhardt, Virchow, Skanzoni, Koelliker), nor partial epithelial degeneration of the parts lying adjacent to the lumen (Heiden- hain), nor transformation of leucocytes and lymph cells (Rauber). None of these is the basic pheonomeuon in the formation of milk, but it is due instead to the assimilating activity of the cells, which send their secretion into the lumen of the cell tube (Ottolenghi). A breaking down of cells of course occurs to a greater or lesser extent, in accordance with their increased activity, and therefore the milk contains cells and cell fragments in varied quantities, without this throwing off of cells or breaking down of cells having anything to do directly with the secretion proper. The throwing off of useless material, and its natural replacement by functionat- ing elements are only signs that the organ desires to maintain itself in a condition capable of continued secretion. Our attention has previously been directed principally to the functions and activities of the milk gland from a physiological point of view; the morphological condition of the udder and some con- stituents of the secretion have also been noted. In this chapter the chemical qualities of the milk will lie considered, as far as this is necessary for the most ordinary conception of these properties. The quality of the milk — in the broadest sense — adjusts itself to the requirements of the young. The milk gland offers it nutri- tive and protective material in a form Avhich most favorably meets the requirements of the off-spring. Tn orrler to give only a few examples attention slioulrl be flivected to the estab- lished facts, which show that there exist absolute relations between the time required 32 Composition of Milk. for the doubling of the weight of the young ami the percentage of proteins in the milk ; between the proportion of certain salts anil the ash constituent, ami the rapid growth of the young; between the growth of the brain and the supply of proteids and lecithin. ]\Iilk consists of dissolved constituents, and this solution con- tains substances in sus])ciision ; in the entire mixture there are also undissolved substances in emulsion. The dissolved ami suspemltMl substances are designated as milk idasma, which after coagulation separates in milk serum and coagidum. The fat is present in an emulsion; there are in addi- tion to this several salts, coagulmns, cells, etc., undissolved or in a ])i'eeipitateil condition. In coagadation the casein wliicli at first is in sus))ensi()n, thickens, and carries down the undissolved suh- stances, sejiarating more or less from the milk serum in which the solulile salts, milk sugar, certain pi'oteids, ferments, coloring mat- ter, etf., remain. The principal constituents of tlie milk, which constitute as well the principal properties of the glandular seeretions, are the parts which have received the most thorough study. The proteids. (lasein, milk albumen, and milk globulin (traces of hu'tomucins, and possibly traces of other pi'oteid substances, which remain after acid precipitation and boilinu-, lieing known collectively as lactoproteins) ar<' the i)rotein constituents of milk. The fat; the milk sugar. The milk further contains lecithin, sarcin, kreatinin, nuclein, urea and sulphocyanic acid. Nothing is known at the i>resent time of some of these constit- uents, whethei- they occur originally in tlie milk, or whether they are oidy sjilit ])ro(lncts, Avhich result during the final production of the various principal constituents, or through Itacterial acticm in the milk; of such sulistanees may be menti(uied pei)tone, ammonia, loucin, etc. Of non-nitrogenous substances milk also contains citric acid, cholesterin and under c(>rtain conditions free lactic acid, alcohol and acetic acid. (lases Avhicli occur free in milk are oxygen, nitrogen, and oc- casionally carbonic acid; the salts are combinations of the bases of sodium, potassium, magnesium, calcium, and iron, with hydro- cldoric acid, sulphuric acid, phosphoric acid, carbonic acid, and citric acid. Principal Constituents. Casein is a proteid especially characteristic of milk, occui'- ring almost exclusively in the milk gland secretion of mammalia, in quantities of from 2 to 4 per cent. (Tt is su])i)osed to occur also in the se(U"etion of the sebaceous glands of maimnalia and in the coccygeal gland of birds.) The origin of ca'^cin is unknown. It was formerly supposed that it originated from an enzvmii- cli;iiii.'e of >orum albumen ]iroduced by the artion of enzyme-like bodies upon the albumen. Ibnvever, simc it has been found that the a'^scrtioii of Kemmerich. rcintixe fo the imrease of the casein at the expen-e of the lactalbumer, after the di- 3 34 Biological, Chemical and Physical Characteristics of Milk. gestion of milk at blood temperature for several hours was incorrect (Schmidt and Tier- felder, likewise that casein is not produced by mixing blood serum and macerated milk gland structure, or milk gland juice and ovalbumin, and especially since it is known that casein represents a nuclear albumin containing phosphorus, the enzymic origin of the casein in the above sense is denied. For a time Basch's hypothesis relative to the origin of the casein was accepted, namely that the nucleic acid which is set free in the alveoli by the activity of the gland, combines with the transuded blood serum, forming the nucleo-albumin, the "casein." Investigation of the experiments of Basch by Odenius, Mendel, Levene and Lobisch proved however that Basch's hypothesis cannot stand. At the present time it must be admitted that the cells of the milk gland break up the proteids into more simple bodies, and then build up the casein from these products. The casein is distinguished from other proteids containing phosphorus, as for in- stance from the nueleo-proteids, by the absence of the xanthin group, the pyrimidins, and the pentose group. The consistence of casein from various species of animals varies chemically to a considerable extent. By special reactions with casein anti-serum (precipitation, complement fixation), the caseins from different species of animals may be differentiated one from the other. In the splitting up of casein into its various con- stituents, quantitative differences in these split products are found which indicate the differences in the individual caseins. The cow casein contains according to C. H. S. P. N Tangl 52.99 6.81 0.832 0.877 15.65 23.141% Ellenberger .... 53.07 7.13 0.76 0.80 15.64 22 60% Burow 52.825 7.095 0.725 0.808 15.64 22.906% Hammarsten .. 52.96 7.05 0.758 0.847 15.65 It is insoluble in water and in alcohol, but with bases forms solutions, the so-called caseinates. Alkali-caseinates form opales- cent solutions, while solutions from caseinates of earthy alkalies represent cloudy, milky fluids. Casein is slightly acid, the solution of which with the bases is accompanied by the formation of salt-like compounds. _ The characteristics of casein are of especial interest, as they give to the milk its well known properties of rennet-coagulation and easy acid coagulation, etc. ' Casein is present in the milk as caseinate of lime, in suspended condition as dicalcium-caseinate, which gives an acid reaction to phenolphthalem, and a neutral reaction to litmus. Acid abstracts calcium from the caseinate, the casein beino- precipitated (that is casein from the milk of cows and other runr- mants as coarse, flaky material, while the casein from the milk of sohpeds and women is precipitated as a fine, flaky substance. f V. ™s difference in its properties is traceable to the physical condition which is mani- fested by the casern molecule of the various kinds of milk (Puld and WoMgemut) bu\ It may also be the result of a variation in the quantity of salt and proteid S^t in the In the presence of di- and tri-phosphates the casein dissolves by combining with a part of the bases, so that the neutral and alka- hne phosphates change into monophosphates (Hammarsten, Casein. 35 Casein is also soluble in other salts, but not, or only to a very slight extent in NaCl, Naa SOi, NaNOa, KCl and others'. In the presence of an excess of acid the casein which is first precipitated is again dissolved into a syrup-like mass, but may be again recovered as casein after neutralization. Neutral calcium casein suspensions do not coagulate in boiling, but they form a pellicle on the surface. (The nature of this manifestation is not entirely clear, but depends probably on the drying and transforma- tion of the casein into a more solid form.) Casein is precipitated even in the presence of relatively small quantities of acid while boiling under this condition changes it slowly into a body not susceptible to the action of rennet. In over- heating and likewise in boiling and over-heating ^^^th small excesses of alkali, casein is split up through liydrolysis. Even under the action of water, casein is split up into a pro- teid body which is coagulated by heat, passes through a filter and is probably identical with whey casein. The latter sulistance is formed after the precipitation of the cheesy substance, through the action of rennet, and is a mixture of reduction products of the casein originating through the action of the rennet (Raudnitz). One characteristic property of casein is its precipitation by rennet in the presence of eartJiy alkali salts. The precipitation of casein has no connection with the action of the rennet as such. Tliis may occur even without having ^irecipitation as a result. If for instance a casein solution is mixed with active rennet, and another solution mixed with inactive boiled rennet, then in the mixture con- taining active rennet, para-casein is formed without any action being noticeable. Only after the addition of soluble calcium salts will precipitation of the para-casein ealciimi result in the glass wliich contains the active rennet, but not in the glass containing rennet which has been inactivated by heating. In the change of casein by the rennet ferment, there results in addition to the substance desif;nated as para-casein, another proteid body free of phosphorus, with the properties of albumose, the whcy-proteid (Hanimarsten). The change of the casein to para-casein, and whey proteid may be a splitting up of the casein, or it may depend on a change in the grouping of the molecules, or it nuiy correspond to a change in its physical condition. The action of rennet in the curdling of milk is practically the same as in casein solutions ; however it is influenced by the other (dissolved) substances, by the other proteids and salts, and pos- sibly also by the physical condition of the fatty emulsion. Curdling with calf rennet develo]is in accordance with definite laws. In milk that has been brought to low temperatures (refrigera- tor) the action of the rennet may be established by subsequent heat- ing; the precipitation, however, will not take place until the mix- ture is heated to 37 deg. C. (IMorgenroth.) Biological, Chemical and Physical Characteristics of Milk. Coagulation may not always appear if the milk is imnieiliatcly heated to 37 (leg., which would indicate that some of the rennet is destroyed at 37 deg. If the same milk is utilized under the same experimental con- ditions, it can be seen that the amount of rennet necessary for the coagulation of the milk is nearly proportionately opposite to the length of time necessary for the coagulation to he completed ; this fact is expressed by Storch and Segelke as follows : "The product from the quantity of ferment and time of coagulation is constant." Each kind of rennet has a certain strength which of course is changeable, and rela- tive for each sample of milk. In strong dilutions of the rennet the action does not corre- spond with the time rule, the time of coagulation becoming continually longer unto infinity; that is, coagulation finally no longer takes place. The action of rennet depends on the most varied factors, which may either hasten or retard its action and influence the precipitation. Acids for instance strengthen the rennet action, likewise earthy alkali salts, while alkalies, allmmoses, neutral salts of high- er concentrations, heating of the milk, talcum, caolin, and muci- laginous substances retard the rennet action. Shaking reduces the strength of the rennet if it is in solution. The following data are taken from a work of Smeliansky in order to show the in- fluence of various ailditions on the rennet coagulation of cow's milk. It appears that: 1. Heating the milk results in retarding the action. The longer the heating lasts the softer and smaller are the flakes. 2. Addition of water likewise retards the action. 3. Mucilaginous substances retard the rennet action from taking place, and the flakes formed are soft and loose. Barley water esjiecially influences its consistence while corn water principally alters the time of coagulation. If boiled milk is diluted with equal parts of a mucilaginous infusion and water, the mucilaginous portions coagulate more quickly than the watery parts. 4. The addition of soda solution renders the flakes soft, and retards coagulation. Milk containing 0..'5% of soda is entirely prevented from coagulating even after standing for 24 hours. Four per cent of table salt renders the flakes softer. Potassium carbonate acts the same as soda while the other salts respond according to their alkalinity. 5. Milk of lime retards the action ; chlorate of lime accelerates it. If boiled milk for instance coagulates after fi% hours, the time required for coagulation after the addi- tion of Ca GI2 is only 8 to 1.5 minutes. It causes the flakes of raw milk to become loose and soft. According to Smeliansky, the reaction indicates the character of the coagulation, and the time required for it. Sucrars exert no influence. On the other hand Reichel-Spiro have determined a slight retarding of coagulation in the presence of a high content of cane sugar. Cooking the milk retards the process (lowering the acidity as a result of the loss of CO, and precipitation of lime salts, Eaud- nitz). In overheated milk no coagulation or only poor coagulation takesplace. The addition of water retards coagulation (Weitzel), likewise physiological salt solution or whey which is free of ren- net (Reichel-Spiro). Hammarsten, Lorcher, Peters, Weitzel, Gerber and Eaudnitz conducted experiments relative to the action of salts on coagulation, the results of which according to Eaudnitz may be interpreted as follows : Rennet. 37 1. The chemical reaction of rennet is hastened by the distri- bution of the rennet and its quantitative relation to the casein, pos- sibly als(j liy elevated temperatures up to an unknown limit. Alka- line earths and acids probably act in a similar manner l)y trctivat- iu'j: the rennet. '2. The chemical reaction is retarded : (a) By the destruction of the rennet : temperatures over 41° C, free hydroxylions; (b) by inactivation of the same: anti-rennet; (c) by changes of the casein: tempeiatures over SO deg. ; formalin. .'!. The physical reaction is hastened by higher temperatures, free hydrogeiiions, and the neutral salts up to a certain concentra- tion, es]iecially the salts of alkaline eartlis. 4. The ]»hysical i-eaction is letardcd by reilucing the concen- tration of tlie iiientionefl salts below a cei'tain point, esjx'cially of the alkaline earths; therefore heating the milk and the salts wiiich ])recipitate lime, and calcinmions will produce this result. Iliglier concentrations of neuir;d salts have the same effect. It nmy also lie ]i()ssil)le that some of the alkaline action should be considered liere. It is known that by the injection of rennet into an animal an anti-rennet may be produce(l. The rennet acting as antigen induces in the body of the rabbit the formation of a specilically acting anti-l)ody, which works against the action of the antigen in tlie re-agent glass, very likely through fixation. Xonnal serum also contains remiet-inhil)iling substances. Tlio action of tho ronnot iiiny bo inhiliitoil or entirely preventeil hy the aililitinn of liorse l>lood in the incubator. The dilutions in which coagulation may now be demonstrated gi\e the vehitive value of the rennet for the respective milk, and if a mixed milk of healthy aininals had been used it establishes the " rennet-titer. " It is to lie regretted that the standard rennet solutions are imt constant, and that they weaken by storing, etc. For this reason it is necessary to establish the rennet-titer before each test on the milk of healthy animals, or on cas(nn solutions. In addition to the rennet of calves, extracts and ferments from other organs of these animals act on milk in a similar manner, such as extracts of spleen, kidney, liver, lung, thvmus, intestine, oNarie-;, testicles and mu^tle-^. Rennet from the stomach of a calf is known as chyniosin : rennet from the stomach of a hog, and from the tM'-tric juice of man as para(diymo'-in (Bang). Rennet enzymes may also be denion--t rated in the bodice of other animal^, lish, Idrds and snails. Biological, Chemical and Physical Characteristics of Milk. Enzymes with the action of rennet have been found m various plants and parts of plants, such as the artichoke, branches of fig trees, candytuft (Iberas pinnata), yellow mustard (Isatis tinetoria), etc, also in bacteria (proteolytic) and ^/^a^*. The individual kinds of rennets vary considerably m their sensitiveness to various Whereas the rennet of calves is very susceptible to heat, and exerts its action readily in alkaline solutions, the parachymosin is less influenced by the harmtul action of heat, but is greatly affected in its action by the presence of alkalies. ^ , . , , The rennet enzymes obtained from plants act in an optimal way at high tem- peratures (sykochymas at 65-70 deg. C. for raw, at 85 deg. C. for sterilized milk). Aside from casein, milk contains proteids wliicli are coagulable by lieat. (1) Lactalbumin which is related to the serum albumin but is not identical with it (it has a slight optical polarization:— 36.4 to —38 against— 60.1 to —62.6, Sebelien). (2) Lacto-globulin may be precipitated with the aid of mag- nesium sulphate. It is contained in milk in quantities of about . 1 per cent, of the total proteids. The lacto-albumin is obtained from the residual solution after saturation with magnesium sulphate and acidifying it, or by almost complete saturation with ammonium sul- phate. 3. Lacto-mucin has been also demonstrated in milk by Storch, Siegfeld, Voltz and Eosengren, whereas other proteid substances such as albumose, peptone, albuminose, lacto-protein, gelatin, galactozymase and opalisin, are considered more recently as products of the preparation of other proteid bodies, at least so far as their appearance in ripe milk is concerned. The proteids which remain in the fluid after precipitation with acid and boiling are collected under the term "lacto-protein." The milk fat consists of a mixture of triglycerides, choles- terin, lecithin, and a coloring substance, and distinguishes itself considerably from the fat of the body and from the nutritive fat by its chemical and physical characteristics. Although the milk fats manifest considerable dependence upon the nutritive fat, as will be seen from the later chapters, nevertheless a transition of the nutritive fat into milk fat cannot be asserted. The same state- ment would also apply to the transition of body fat, although in this instance a closer relationship between the substances must be admitted. It is possible that transitory relations exist, by means of which split up body fat may be converted in the milk gland into milk fat, and thus the nutritive fat takes part indirectly in the formation of milk fat after first having been deposited as body fat. It should be considered however, that the specific activity of the cell builds up the fat from the constituents at hand, and utilizes whatever material is placed at its disposition, such as nutritive fat, when such is present, or body fat in emergencies. The product will approach in its properties the material which has been utilized, but will always remain peculiar to the species of animal producing it. A formation of fat from proteid is possible, as may be seen when cows are fed with substances free of fat, and after the body fat deposits have Ijeen used up. It is probable that the carbohv- drates of the food here take part in the formation of fat. Fat Content. 39 The fat wliich is contained in milk in the form of very fine globules, causes in part the white color of the milk through the reflection of light. The size of the fat globules varies in the milk of the same cow and depends upon the individual, length of the period of lactation, the race, feeding, and upon whether the first, middle or the last part of the milking is examined. According to "Woll, D'Hunt, Sehellenberger and Gutzeit the diameter varies between . 8 and 22 /. with an average of 2 . 2 :2 . 5 :2 . 9 :3 . 6 /x. Variations in the percentage of fat are caused by change of food, etc. These changes also have an influence on the size of the fat globules, and according to WoU the fat globules become larger with dry feeding, a statement which could not however be confirmed liy Sfiiellenl)orger and PankowskJ^ According to the investigations of these authors the feeding of green forage, especially clover, produces large-sized fat globules. The length of the period of lactation should be considered since the variations of size at the beginning of laftation arc more con- siderable than in ripe milk, in which the milk globules appear more uniform and mostly of medium size. In colostrum they vary from the si7os of dust to 20/i ami over. Donne ami Schulz fonnd that colostrum contains large, broail oil drops in addition to the small and minute fat globules, whicli show a less uniform appearance and contour, when compared with the usually spherical fat globules of ripe milk. In interrupted milking the size of the milk globules liears a certain relation to the fat content. With the iuciciiscd quantity of fat which obtain in the milk toward the (mkI of a siiiulc milking, the size of the fat gloliules also become larycr (Schellcnlteii^cr, Woll). With the extension of the lactation period the size of tlic fat globules decreases, but their number increases. According to Gut7eit and Sehellenberger the following values were obtained in milk from different breeds: Si?e in 1/1000 mm. Xo. per ce. in millions. Gutzeit: Sohelleniierger : Voigtlander 5.7:'. 194+ to 447(1.9 Jersey '■"•■'< 2.9" iniU.l to 4ii4?..?. Kast ' Priesian "..'. 2.S0 2.521.0 to .5911 .0 Angus 2 95 2.20 2^^0.0 to 0200.0 Nimmentlial' ".'.'.'.'.'.'.....'. 2.50 2995.0 to 5210.3 IVssau ?.n7i\0 to r,?.n^fi Su-iss 2,.'^.i 4ii(K.O to 5:i20.7 Shorthorn 2.70 ^[ontavoner 2.02 Ilolstein --■''^ Breitenburger -■-*'' Aciording to Grimmer the number of milk globules fluctuated in 21 tests on three herds of^Mackish-brown lowland cattle in Pomerania, from 1,330,000 to 3,07.3,000 per cul'ic millimeter, having an average diameter of 2.6-3.7^. The milk globules retain their form through their surface tension and are not surrounded In* special capsules which could be considered as meml>raiies, 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 wa?hing (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 goats and cows, however, a temporary hyperglycosemia anci glycosuria appear. If parts of the gland remain, lactosuria results. After the injection of glucose, lactose appears in the urine (Porclier), likewise after the ingestion of large quantities of dex- ti'ose. 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- phoric acid, hydrochloric acid, carbonic acid, sulphuric acid, citric 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. Eaudnitz and Grimmer have recently published compiled arti- cles 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 cornposition 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 casein 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. 4^ dition of alkalies to milk free of fat renders it transparent. Ham- uiarsten 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 I)econies less transparent the smaller the fat globules are. This is most strikingly apparent when the fat lilolmles are bi'oken up to dust-sized bodies (for instance through homogonization). The appearance of fresh milk is also influenced liy thi' coloring matter present in the milk plasma and in the fat. It is known that the skimmed milk of certain cows varies considera- )j1\' in color ; at times it is bluish white, sometimes more yellowish .urccn, again transparent, other times of a non-transparent whitish cdlor, and also the fat has a more yellow color during the pasturing of the animals than at the time of stable feeding. The non tranpparenpy as mprtionerl above is no proof of the presence of fat in the milk; therefore all methods Avliich are destined to establish the cjnantity of fat or addition of water liy tlie establishment of tlic wliitciiess, are of no use, as for instam-e, Ileeren 's pioscope, Fescr's lactoscope, etf. Tf milk is allowed to stand for a time, cream forms on the surface; the fat gloliules rise and coilcct usually as a distinct layer of cream above the milk. The i-ayjidity of the separation depends (in the temperatui'e, the size of the fat globules, and the density of the milk plasma. The quantity of tlie cream is not in parallel rela- tion to the quantity of fat ; it depends on the size of the fat i^lobnles. The sei)aration of cream may lie hasteneil and increased by centrifugalization. During separation while allowing to stand, about 85% of the fat rises to the surfac(\ while by a perfectly operating centrifuge the separation of cream mav Ix^ accomplislied uptoO.Ol^r of its fat. The specific gravity of the milk depends on the solid snl)- 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 inqiossibility of speaking of milk of normal composition, one cannot speak of milk of normal s))ecific 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 liasis of the value of the s])ecific gravity of the milk fat (about 0.93), and the solids or dry substances (1.6001). which is quite constant, is according to Fleischmann : 42 Biological, Chemical and Physical Characteristics of Milk. 1000 1000— 3.75 (d— 1.2 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=1.2f+2.665X ^QQ^-^Q Q s 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 ~ sXd— (100 s— 100) 4. Finally the fat contents when the solids and specific grav- ity are known : f^O. 833 d-2. 22^^=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 plaiisible 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 . 3 deg. C. The freezing point of milk is somewhat lower, namely — . 54 to — . 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 conductiMiity 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 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 Ijy 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. Higlier 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 l)y the aid of the fat contents and the spcfific 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 s])er'ific ni'avity of the milk serum, or still lietter ))y tlie refraetoseo])e to determine tlio chlorids of ealeiimi serum, wliich renders more rapid work possilile. Thi 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 issuecl In' \'alentin in 1879, and later continued l)y Villiers and Bertault, Braun, Utz, Lara, Eadulesku, Ripper, Schnorf and others, on icn- net serum, acetic acid serum and milk serum, Avhich had been pre- pared liy voluntary coagulation. The given values of the authors varied in accordance with the method of preparation of the sermn ; nevertheless it could be estab- lished tliat comparatively unifonn figures were obtained whenever the work was carried out under similar experimental conditions. In 1!M)S Cornalba showed that contrary to the variance in the amount of colloidal sul)stances 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 tlierefore constant results in the examinations, the same as the (>xaminations which lead to the establishment of the fat-free solids, which still include the casein. Examinations of serum are tlii'refore of the highest practical value for the demonstration s 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 Eoth- 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 calcium serum we possess means which are better adapted than any other to the detection of the adulteration of milk by water. Eefrac- 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 ref ractometer, 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 37.7 " " 5% " 37.5 " " 6% 37.3 " " 7% " " " 37.1 " " »% i i 7o 36.9 " 36.7 " " 10% 36.5 " " 11% 36.3 " " 12% 'o I Qt 36.1 " " Ibyo 35.9 " " 14% 35.7 " " 15% 35.5 " " 16% 35.3 " " 17% 1 ( a 35.1 " " 18% 35.0 " " 19% 34.8 " " 20% 34.0 " " 25% 33.3 " " .30% " " " 32.6 " " ,35% " 32. " " 40% " " " 30.9 " " 50% " " " 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 ]\[ilk. 45 The experiments of Weigner and Yakuwa are of interest since they demonstrate that the refraction and specific gravity of the chloride of calcium serum are theoretically of equal value. Islai 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 ])(issesses. 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 ( 1*1' da\ s), up to 1 .0. Changes of feeding have no marked influence. The milk of individual cows failed to show any important fluctua- tion dui'ing the time in which the tests of the entire stable were made (O.L> to O.fi). ]More considerable may be the fluctuation between the find- ings of normal milk and the secretion from cnws with an affected udder, and the variation between the findings of milk from the same animal while healtliy, and within L'4 hours after the udder becfimes diseased. The milk of individual animals with affected udders shows, not infrequently, values wliich are considerably below the values of normal milk. This has been pi'()\'ed by the work nf ^letzucr, Fuchs, Jessei' and TTenkel, and from the <'xi)erieuee of the official milk control station. These abnormal values, however, do not affect the worth of this method, if the results ai'e 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 yios- 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. Tender the term ferments (enzymes) those substances are incluiled which hasten chemical changes with an explosion-like ra))idity (Uexkuell), and without using themselves u]) they act in relatively minimal quantities. Their activity is inhibited by the products of the reaction. Iliglier degress of heat and certain toxins (ferment toxins, as for instance hydrocyanic acid) inhibit their activity, the ferments being thenuolabile. The author desig- nates as fei-ments all of those bctilies with ferment-like action, with- out consideration as to whether the nature of the ferment is known or not. A careful distinction must be made between original fermeu- 46 Biological, Chemical and Physical Characteristics 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, ' ' aldehydcatalase ") . 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, "Galactose," found by Babcoek and Eussell and bodies acting like pepsin or trypsin (Jensen, Freudenreieh, Spolverini and others). These are only present in very small amounts. Kinase and -jihrin 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. Rnllmann in 1910 proved by the examination of aseptieally 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 carbo-hydrates, the amylase (diastase, galactoenzyme), whose action is similar to the ptyalm 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 c. c. 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 iits activity lies 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. -^ •j^ uoLiuii The occurrence of direct oxydase in milk, the action of which appears even without peroxide of hydrogen, is uncertain. RuU- 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. by abstracting active oxygen after tlie formula HoOo=H20+( ) (Jensen). The active oxygen oxidizes the added "chromogenic" sulistanees, 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- tinguislicil from raw milk by the non-appearance of the color reaction. The action of the superoxydase (Raudnitz) or catalase (Loew) (levelops in a different way. It splits the H2O2 according to the formula 2 I-L02=2 H20+2(J, which join to a molecule of O2. Otlier authors include the superoxydase with the oxidizing fer- ments, as the freed oxvi^^en is utilized in the body for the oxidation (Scli.n'mann). Aeeordiiig to others it is included with reductase, as the action of the ferments on H2O2 eqvTals a redi;ction of 2 HjO, and molecular oxygen (), which passes out without lieing iitilized for oxidation, whereas the oxygen freed by peroxydasc is imme- diately utilized for further oxidation changes; tlxMcfore the per- oxydasc 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 uland, especially from the leucocytes. It is secreted, but may be set free in the breakini;- down of cells or may appear bound to the cell. That catalase is derived from the cells (es])ecially leucocytes) is not cdiitiadicted 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 Friedjun^-, Heclit aiul Pallazzi, and later confirmed by Koning. This also explains the reason for the centrifuge foam, rich in leucocytes, givint;- such a strong reaction. Since the formed elements (cells) are pi-eci])itated with the casein, and prol)ably a part of the free ferment is also drawn down Avitli 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, etc., affect catalase, even if it is relatively resistant. A leucocytic extract, Avhicli was kept exi)osed to the light in the laboratory of the author, showed even after months, an unweakened action to H.O:, while hydrogen suljihide, hydrocyanic acid, potassiiun cyanide, mercuric cyanide, liarium nitrate, hydrochloric acid, sulphuric acid, acetic acid, ()xali(> acid, and potassium nitrate affected its action (Faitelowitz). It appears noteworthy that H2O2 inhibits the ferment in its action. In the presence of excessive amounts of peroxide of hydrogen the ferment splits up less H2O2 than if the diluted peroxide of hydro- gen is gradually addeil. 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," tlie nature of which is by no means definite, is Schardinger 's formaUn methylene blue reductase, which according to Trommsdorff, will be designated as Schardinger 's ferment (synonyms are indirect reductase, aldehydcatalase, 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 formic 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. Ebmer and Sames established more recently, the interesting fact that boiled milk with 0.3 c. c. of a 1% of ferrosiilphate solution also gives the reaction, and this difap- 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 en7yme 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 in milk. 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 wlien 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 bodv 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 pi-oteid, animal cells, plant cells, plant proteid, living and dead bac- 1er-ia, bacterial substances, toxins, etc. The antigens are distin- Antigen Action. 49 guislied by groups, whicli make possible tlieir combining witb cer- tain groups of tbe 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 lioison-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-calh'd receptors, which bind its haptophore group. If this has been the case the toxophore group exerts its aftion, 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 tliis i-es))ective toxin. It is possible that as a result of the receptors of the cell com- bining with tlie toxin, the cell molecule is (Icstroyed. But if the damage is not too serious, the protoi)lasm is stimulated to produce numerous receptois, — an over-production in fact. As not all of tliese are necessary for the performance of the cell function, the superfluous ones are rapidly thrown off into the boily fluids. If such free receptors combine with the haptophore groujis of the toxin, the latter is no long(>r able to combine with the protoplasm of the cell. These fre(^ receptors therefoi'e pnitcrt the liody against renewed action of the toxin, that is they act as antitoxins, and con- stitute tlie antitoxic part of the serum. Besistines of the suckling is considered. It is true that Mi(^ssner succeeded in proving that mice die from tetanus when they are fed with raw milk from a cow affected with tetamis, 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 hotulinus, 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 ricmus seed and its flower. An elimination of ricin Avith 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 globulins 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 Eomer prove that certain immune substances of niilk of hke origin pass throuo-h the intestines, while in feeding sera or anti-substances of like origin contained m niilk of unlike origin the quantity passed was only very slight. Thus Eomer succeeded in demonstrating passive immunity m 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-toxm was mixed mth the milk as a serum of unlike origin, but l^nlwS^^/+"TiT' ^?''>' ?^ ™^^k« «"g^" absorbed was smaller than that of hke origm. The absorption diminishes mth the increase of the age of the animal. Eelative to the passage of other immune substances from the milk into the blood of the suckling, the same experiences hold as a rule as m the case of milk containing anti-toxin Milk IS not only a carrier of anti-bo^dies, and possibly of anti- Tnhtc 1. Anilii pui'uleiit fibi'imnis nuistitis. Dilatinn of the l)ln(n] \ cssrU ( f ) , with exmlate of nuniei'ovis celU into tin- jilvooli and excr('t'n-\' tliiri. Hftiititow [in — SntlaTi III. li. \ fr j" - '-^*. "/VTtBfimii^'^' ^••♦•^a*'*** t^*»«. .'J/ '<^' ,f' if ■ mMM Wi Concrement formati..., in milk stasis (a and in maslttts (b); inactive portion of the i:,nsl. Milk Ihnil'll'. Precipitin. gg g«'n, but as a proteid-containing material it is an antigen in itself, or ratlu-r a collection of antigens, ^vliicli may again produce anti- Doclios m tlic body of an animal. These anti-bodies against milk not only develop in artificial administration by injections, but also under certain C(ni to 8 times at intervals of 1 to 4 days. In from 14 to I'D days after the last injection the lactoserum may be tested for its effectiveness and if found suitable, may then be drawn. For this purjiosc tlie 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 glolie, or by rubbing it -watli xylol, and the vein is then punctureil ^\■ith a fine hypodermic needle. Several cubic centimeters of blood are drawn, which is alloAved to coagulate; the blood clot is separated and allowed to stand for 24 hours in an ice chest. The test is made as follows : 1. Establish the dilutions of the serum which are capable of producing a visilile precipitation in 3 c. c. of milk dilution, with 1 :60 physiological salt solution, or 2. Establish 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 ]n'ecipitation. 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 is allowed to stand, the serum is dra^^^l off in quantities of 2 to 5 c. c. into small vials, and placed in an ice box for safekeeping. Chapter V. PROCUREMENT OF COW'S MILK. As lias already been mentioned milk secretion may be retained for a long time by proper emptying of the gland and l3y 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 bv drv milking, Avhile "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 :\retliods of :\rilkino:. .If) as "streak milking" or stripping Avitli bent thumb. The "streak iiiilking"-may be completed Ijy stripping or by full handed milking. Full handed milking and this method combined Avith ' ' streak milk- ing" are according to Henkel permissible; the other kind of milking should l^e prohibited since the teats are too much extended. The uddor should be milked liy the dry method since this method of milking is more cleanly than moist milking, in Avhich the fingers become moistened by tlie 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 liy many milkers on account of tlieir convenience, and even if they are urged to carry out the ordinary dry milking, as soon as they are left with- out supervision tliey will at once fall into the same fault. The order of milking the various teats diflVrs. ]\[ilking from the same side is supposed to induce the devcl()]mient of the side first milked, since the half of the udder first milked is workcil with fresli strength wliile the subsefimmtly milked r|uartevs are not emptied as Avell on account of the beginning weariness of the milker and tlierefoi-e they develop less perfectly. The hind quar- ters are either not emptied entii'ely when the milkers have com- pleted the milking of tlie 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 emsswise, when the hind quai'ter of one side of the udder is milked at the same time as the fore quarter of the other si(l(\ Therefore it is advisalile to milk the fore quarters together and the hind quarters toucther, and the milking should l)e undertaken first on those iiuarters which ajijiear to be most distended. With the drawing of the milk from the udder throngh milking the teats, the complete act of milking is not conchnh'd, as the udder has not vet been sufficiently exhausted in its production. The cause of this may lie in the fact that the milk cannot lie emptied by the simple sucking action from the smallest milk ducts and alveoli, or that after tlie 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 (if 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 niostlv studied, is that practiced by Hegelund, a Danisli 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- chyma. 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 loAvered 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, WoU, van der Zande and Henkel, and Wenk, speak of the excellence of the method of Hegelund. According to Henkel the increase of the milk jdeld in 37 himmenthal cows was 217.4 gm. (3.4%) per milking on an aver- age. Wenk succeeded m obtaining from 24 cows 4.5 kg. of milk per day more than vnth the ordinary method of milking. Of course against the increase of vield must be" placed the Methods of Milkiii- 61 additional work and time, wliicli 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 Algaiuer 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 wMch. must be considered in the formation of milk may be separated into internal influences which lie in the individual characteristics and in the immediate condition of health of the animal, and in outside influences, such as stabling, feeding, etc., 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, etc. 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 lireeds which fatten especially well, milk breeds in which milk production is especially prominent, 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. Ac- cording to the quantity of milk produced, the breeds are headed by the Holsteins, Angler, Oldenburger, East Friesian, Breiten- burger, Wilstermarscher, Dithmarscher with 20 to 25 Hters of milk per day per animal at the height of production, with percentages of fat from 2.5 to 3 to 3.4. Smaller quantities of milk are given by the grayish-brown mountain cattle, the Swiss and Algauer, with 3.6 to 3.7% of fat, and the spotted mountain cattle, for instance Simmenthal, Misbacher and Pinzgauer, with 3 . 5 to 4% of fat. The fat content of the Westerwalder and of the Schlesian red cattle 62 Influence of the Breed. g3 vanes liotween .3.5 to 3.67c, while the English Shorthorns and Ayrshires give 3.7 and Z.S'/o ; the richest in fat is the milk of the Vogelsl)erger and Harz cattle (3.9 to 4.2%) and that of the Jer- sey with 5 to ')A% (Ramm). Reference should be made here to the following resnlts of tests of production made with Simmenthal, ^'ogelsboiger, AVesterwaldern and Lahn breeds of cows. Simmenthal Lahn Vogelsberg WesteTwalrl Average weight of the tested animals ,578* .502 4'27 P.O.") kg A\or;ijii> production 240." Sri-'d 1919 1^7s Fat .-oiitonts 4.001% 4,0017c 3.74% 4.1% Individual maximum production .... 4.">('2 39.1.1 3Snii 32.i4 kg For 100 kg. body weight 4:!1.1 .'2S 4."i0 477.4 "^ *The cow with maximal production stood last year in ninth place. 17 cow.'^ ]iro- duced over 3000 kg. each. The fluctuation is not in fat content alone, but also in the other solid substances. Milk which is rich in fat as a rule contains more of the otlicr solid constituents as well. Tlie iiroportion of individual factors of the dry substances is variable; in cattle from the highlands for instance, the casein was 76. "-'4';''^ of the dry sub- stance, in cattle of the lowlands it averaged 73.78% (Fischer). Fat from the milk of the mountain breeds is generally under otherwise similar con- ditions, the richest in fatty acid of molecular weight; the tat globuh"^ nf the breeds of the lowlands are smaller than the fat globules of the cattle from the highlands. Babcnc'k mentions that .Jersey and (lucrnsey cows produce larger and more uniform fat globules than the llolsteins, while Ayrshires have small, irregular fat globules in their milk. Milk with large fat globides is preferable for butter making, since thcj^e produce butter of good consistence and good taste with a low melting point. The ash content of milk from higlily lircd animals is sonic- times somewhat lower in CaO and Pc<>, than that of the common breeds, but the fluctuation is such that definite deductioiis cannot be established. In hiyhlv improved breeds Paii(^s found: CaO in 0.143 to 0.227% and P,0.-, in O.IS to 0.273^; ; in common l)reeds the same elements amount to 0.15 to 0.204, and 0.15.3 to 0.296, respectively. These characteristics of breeds are general, but they are not so constant that individual strains, individual families, and es])(>- cially particular animals may not present exceptions. This fact forms the basis of breeding for increased milk production within individual breeds. Good milk cows should be bred to bulls, whose mothers and sisters were or are known to be good milkers, and then it may be expected that the good characteristics of the family will be inherited. In experiments extending over eight years Hosstrom tried to discover whether the characteristics of producing milk of certain fat contents could be transmitted by bulls to future generations. The large majority of female progeny produced a higher fat content than the milk of their mothers, which points to a positive influence from the male animal. In ca-es in which the fat content of the mother was .3. us to .'5.77%, the fat content of the njilk of the daughter increase.l mate- rially;- but as soon as the fat reached or exceeded .■'..777 . the influence of the bull was no longer sufficient to further increase the percentage of fat, and the percentage re- mained lower than in the mother. (The experiences of Hogstrom's were confirmed by the rule laid down by (.alton.) 64 Internal Influences on the Character of Milk. The great variation which occurs in the milk production of individuals of the same breeds depends on hereditary qualities. According to the statistics of the dairy control station at Algau, animals of the Algauer breed produce : Quantity of Fat Percentage Quantity of Milk Pat Maximal production 5201 kg. 4 . 603 181 . 93 kg. Minimal production 1255 kg. 2 . 493 45 . 31 kg. Difference 3946 kg. 2.11 136.62 kg. Among 50 of the Jeverland breed Maximal production 8699 kg. 3.713 286.76 kg. Minimal production 2449 kg. 2 . 482 75 . 21 kg. Difference 6250 kg. 1.231 211.55 kg. The production of single individuals during the lactation period is sometimes remarkably large. Some of the following data relative to production is taken from Kirchner's handbook. Percentage Quantity Autlior Cow Quantity of Milk of Fat of Fat Kirsten Wesermarsch . . 11291 kg. 2.78 324 kg. 5th calving Kirsten East Friesian . . 9047.75 kg. 3.07 277.77 kg. 6th calving WoU Guernsey 6768 kg. 5.745 388.8 kg. "Yeksa Sunbeam" Kirchner also quoted a case in which a farmer observed that a seven-year old cow in the second month after calving still pro- duced 50 liters of milk per day. Just as the quantity of milk and percentage of fat may vary, so also the fat-free solid substances may vary in the individual's, although only within narrow limits. The rule also holds good here that an individual with milk rich in fat will at the same time pro- duce more fat-free solids. Normally fed animals Avhich are not individually large pro- ducers cannot be brought up to a remarkable increase of produc- tion through any agency. The elimination of the poor assimilators of food m favor of good producers, which is a matter of economic necessity, should be based upon the capacity of the individual cow to properly utilize her food. Only through a systematic test of milkmgs and production records can the profits of the dairy be increased. In judging individuals as milk producers by their external conformation, the following rules of the German Society for Breeds and Breeding may serve as a basis : Influence of Age. 65 (a) Heavy milk production is usually associated : 1. With low body weight, :2. With low measurement at the shoulder, 3. With a straight back, although slight deviations should not be considered as signs of small milk productiveness. 4. AVith more or less prominent hips and rump according to tlie characteristics of the breed. '). With the more pronounced depth of thorax; heavy milkers are often narrow and flat chested ; 6. With long shoulders, 7. With long rumps, 8. With long, narrow head, 9. Generally with fineness of horn, 10. With fine bony structure ; 11. The most important is the udder. The best cows have large udders of spongy-granular consistence, with largo tortuous mammary veins, large milk wells, and easily movable skin. The skin should lay together over the perineal surface of the udder in 4 to 6 or more large, well developed folds. The udder should collapse thoroughly after milking, and the animals should be easy milkers. Relatively early calving seems to have a good in- fluence. The possibility of estimating the qualitative production of milk from external conformations is only very slight. As a rule, as shown by investigations, the smaller and slieen made on the influence of coition and the beginning of another pregnancy. However the milk of cows far advanced in pregnancy frequently has a lower value. It coagulates sometimes as early as in the sixth, seveiitli, or eighth month of the gestation period. Finally it becomes slimy, y(>llo\v, and shortly before the cow goes dry it shows a similarity to colos- trum. The amount of phosphoric acid and lime, contrary to that in colostrum immediately after calving, is diminished, and the taste is bitter and rancid (Backhaus). If cows are spayed 5 to 6 weeks after calving the milk is supposed to be richer in fat, casein, and ash. The lactation period of such cows is considerably lengthened, according to Gouin ex- tending to 6 years. Lajoux on the other hand states that in healthy animais the quality of the milk remains the same, but during the course of lactation" the cows do not dry off so rapidly and the yield is therefore greater. Milk which is produced after abortion is supposed to be smi- ilar to that of ripe milk (Schaffer and Hess). The lactation period however is short, and the milk yield small. If the cow remains farrow for a long time a greater yield is obtained. This however is only slight, and does not compensate for the shrinkage during the latter part of the milking period. Influence of Diseases. Relatively little is known of the chemical changes which milk undero-oes from the influence of general aflfections of ani- mals We ai-e in possession of better information relative to the gg Internal Influences on the Character of Milk. occurrence of specific disease agents in milk, and it is known that these pass into the milk either directly from the blood being then eliminated with the milk, or else they reach the milk through sub- sequent contamination of the milk with excretions. A rapid diminution of the milk yield is characteristic in all acute diseases associated with great pain and fever, and in some cases a sudden cessation of the secretion may be observed. Whenever the yield of milk of a cow suddenly shows a con- siderable diminution, all of her milk should be excluded from mar- ket, even though the animal shows no visible affection and before the disease can be recognized as a general or specific affection. In the sense of the pure food law the milk of every severely affected cow should be considered unfit for food without any further con- sideration. Sometimes this unfitness of the milk is manifested by strong objective perceptible changes, as compared with the secretion of healthy animals. The milk may become bitter, salty, have an increase of ash and albumin, and coagTilate more rapidly than healthy milk (Jensen). The fat content of the milk is at the same time diminished or in- creased, while the sugar and ash contents may show fluctuation. The amount of catalase present, according to Spindler, may in- crease considerably, especially in cases of peritonitis and tubercu- losis. The reaction of the milk remains acid or becomes slightly alkaline. According to Schnorf, most of the internal affections, even when the udder is not involved, produce a diminution of sugar and proteid contents as a result of increased metabolism. The electrical conductivity of the milk of animals with general affections is subject to great fluctuations. After tuberculin injec- tions with subsequent fever, the milk shows a slight increase in its electrical conductivity. The index of refraction in pathological milk is normal, and not diminished; the temperature at which freezing occurs is not infrequently higher. During the course of individual diseases the following should be considered: An elimination of toxins and toxic products of metabolism with the milk is to be feared in all septic and pyemic diseases. If with this there is a possibiUty of contamination with pathological excretions, as for instance in septic metritis, hemorrhagic or ichorous enteritis, or in the retention of putrid afterbirth, the milk should be considered harmful. In septic metritis the infective agents pass from the uterus into the meat and into the udder, from which they may be eliminated. Basenau demonstrated the Bacillus morbificans bovis, a meat poisoning organism of the colon typhoid group, in the meat during the existence of septic metritis'. The stnpyJococci and streptococci which are frequent participants in mixed infections of the uterus, are also eliminated with the milk, provided the udder has not already ceased its secretion. Influence of Disease. gg ^h\k from cows affected with acute and sub-acute intestinal inflammations should bo judged iu the same way as milk from animals affected with septic metritis. The ingestion of milk from cows affected with bloody or fetid diarrheas should be especially guarded against. The appearance of sickness in man after the ingestion of such milk has been satis- factorily proved by Gaffky and Follenius. Two assistants and a helper of the Hygienif Institute of (iie-^en drank milk of this character ami became sick with dullness, headaches ami idiills. After two days diarrhea, vomiting ami high fever appeared. The clinical manifi'stations in the two assistants simnlatcd those of typhoid fever, while in the helper they were similar to those of Asiatic cholera. The milk originated from a cow affected with hemorrhagic enteritis. Gaffky demonstrated rapidly growing and strongly virnlent i-nlon hacilli both in the bloody excrements of the cow and in the stools of the affected patients. In the presence of infectious diseases the milk of the en- tire stable should be withdrawn from use, or sliduld i>c rendered safe by suitable treattnent, as for instance by pasteurization. Such milk should never be sold ;is certified or iid'ants' milk. .leiiseii ex- tends this prohibition even to milk fioni stables in which white scour of calves, and other calf affections of an infectious natnre have occurred. Dangerous properties of the milk should also l)e considei-ecl in the appearance of other diseases, as for instance malignant catarrh- al fever, purulent broncho-pneumonia, traumatic jiericarditis, rin- derpest, etc. (Bongert). In all cases of hemorrliagic, jiurulent, acute or chronic inllammations of the kidneys tlu^ milk sliould b(> judged similarly to milk from animals with inteslinal inflaninia- tions. In such affections the freezing point of the milk n]ti)roaches zero, and the refraction index is lower. At the same time these values in animals affected Avith inflannnations of the kidneys vary extensively. Special Infectious Diseases. Tuberculosis of animals, especially its hygienic importance, is considered here in connection with tuberculosis of the udder. It should be mentioned at this point that some investigators be- lieve that the toxins of the tubercle bacillus pass into the milk. A change of the quality of the milk will occur only in cases in which the advanced chronic affection of the animal results in lasting emaciation, or when an acute attack of the disease, associated with fever, appears during the chronic course of the disease. In tuber- culosis the milk may become bluish, and poor in fat, the sugar and proteid substances may be diminished, or the latter may be even in- creasi'd (Storch). Several tables, which indicate the ex]ierimental results of :\ronvoisin, are taken from Grimmer's "Chemistrv ami Phvsiolo-v of Milk." 70 Internal Influences on the Character of Milk. 1000 gm. of milk contained Tuberculous cows without Healthy cows tuberculosis of the udder. Acidity as lactic acid 1 . 543 . 664 1 . 292 Total nitrogen 5.87 8.67 4.21 Fat 46.5 29.6 59.7 Sugar 43.5 29.8 43.9 Solids 142.3 126.05 147.5 Ash 7.3 8.2 6.7 Clilorin (sodium chloride) .. 1.4 4.13 1.05 Freezing Point — 0.55 — Eef raction at 15 deg 1 . 3434 1 . 3416 1 . 3442 In rinderpest, according to Busson, the amount of fat and sugar diminished rapidly, whereas the casein, albumin and salt increased. The passage of the contagion of rinderpest into the milk in a direct way from the blood is probable; the milk, how- ever, can be contaminated with certainty through infectious secre- tions and excretions. Einderpest is of no practical importance from the standpoint of milk hygiene, to most of the European countries (with the exception of Turkey), since it has been eradi- cated with the aid of veterinary police measures and even in the event of any possible introduction, it will be immediately sup- pressed. Milk from cows affected with contagious pleuro-pneumonia is supposed to have caused the death of children (Eandou, Lecujer and Wiedemann) . Secretion of milk is immediately reduced at the onset of this disease, it becomes poor in fat and sugar, richer in albumin and ash, its appearance resembles that of colostrum, and its tasteis pecuhar. The contagion of pleuro-pneumonia appears to pass into the blood but rarelv, and therefore its elimination in the milk can occur only exceptionally, if at all. Contagious pleuro- pneumonia IS also subject to the most stringent veterinary police measures, and therefore has but little practical importance for milk hygiene. Similar conditions prevail with pox of cattle. This disease however demands our interest for the reason that the infectious agent o± cow pox must be considered as a mild form of smallpox ot man. Cattle usually become affected through transmission of the disease from naturally infected men, or from those vaccinated with cow pox The infection occurs if during milking the contagion i^"" ^t^^^^'H^ ^I"^? ^^'^^^^ 0^ invisible wounds of the skin of the udder. The infected teats manifest roundish or oval, hard papules of the size of a pea, which after 1 to 2 days change into vellowish- white vesicles of a mother-of-pearl luster. After ripening into pus- tules which requires froni 8 to 10 days, the lesions show a charac- teristic clepression m their center, the so-called navel of the pox. I hey either rupture and suppurate, or dry and heal, leaving a superficial sear. ' ^ The udder becomes sensitive to pain, the milk is thinner, and Influence i/f Disease. 71 of lower specific gravity, but richer in albumin (Jensen). The injection of the contagion of pox into the ducts of the udder results in the development of pox vesicles on the walls of the milk ducts. After 2 to 3 days a swelling of the udder, with increased sensitive- ness, develops and the secretion is changed. It becomes purulent and bloody on the eighth to the tenth day (Lienaux and Hebrant). Transmission from animal to animal may be brought about by milking, and the entire herd in a stable may rapidly become af- fecteil. The course of cow pox is usually benigti. According to Hciz the milk becomes I'ich in cells, contains colostral bodies, and it has an unpleasant taste. Careful examination showed the fol- lowing results : Beginning of After 13 After 40 observations days days Specific gravity of the milk 1. ()-*>') l.tH'TD l.O-l") Specific gravity of the whey 1 . 0245 1 . ( )2:i.l 1 . ()2( )!) Acidity according to Soxhlct-llcnkcl. 5.;) 6.() 4.1 Fat .').;!(;% 4.02% 5. .14^; Solids 13. ;n ll.s-J 12.2.-. Fat-free solids 7 .0.-) S . si (i . , 2 Ash 0.72 72 O.s Transmission of pox from cattle to man is of course veiv readily possible, and is not at all uncommon as a result of niilkiiii;- affected animals. After the ingestion of infected raw milk tlie jiox exanthema may develop on the 1'ace (Jensen). The so-called false or gangrenous variola which nuiy be fre- quently observed on the teats of fine-skinned, fresh niilkin^- animals should not be mistaken for true pox. These eruptions are pro- duced by the ordinary pns-producing organisms, wliicli have been rubbed into the skin during milking or have ]ienetrate(l the skin by means of various injuries. Small furuncles and skin abscesses result, which heal without influencing the formation or secretion of the milk. Healing is of course retarded through the act of milk- ing, and during thepreseuce of the pus cells, blood and pyogenic organisms may pass into the milk in small quantities. These false pox lesions are not very important. Of much greater importance than cow pox is foot-and-niouth disease which sometimes appears extensively. This is a highly acute febrile disease which is transmitted to cloven-footed animals with remarkable ease. The most strildng s^Taptom which occurs in association with the disease, the vesicular eruptions, may also affect the udder, and es]iecially the teats. The udder swells, becomes painful, and red-bordered vesicles develop in sizes up to that of a walnut, which burst durino- milking or spontaneouslv, leaving painful ulcers. During the be.ginning of foot-and-mouth disease the yield of milk is considerably dimin- ished, sometimes one-(iuarter less than the usual yield, as a result r(mi)s, and in order to reduce the economic losses as low as itos- sible, the milk of these groups should be treated in different ways. Heated milk from the non-affected animals for instance, could be utilised as infant's milk. The milk from slightly affected annuals could ho marketed as ordinary milk [after pasteurization], whde the milk from the severelv affected cows or milk changed m its consistence, should be excluded from consumption even in a heated condition Ev.ui with this separation the losses will necessarily be high as a I'esidt of the enforcement of stnngeiit sanitary regu- lations. , , ^ . , \<.-ordin- to Ebert sour milk .1 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 oedema, 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 parenchjina 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 eases 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 mav become infective through contamination with feces from such bacilli car- 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 epizootieally as a disease of the soil, vet 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 li/o 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. 10 Lohnert 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 )jy 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. Nev<'r- theless the danger to man from the ingestion of such milk is hardly probable, since it is impossible to aff.-ct experiment animals l)y feeding fresh milk (exceptions are rats and mice). A nursing infant of a woman affected with rabies remained well, althougli it was fed with the milk of the patient until one day l)ef()re lier death (Bardach). The uninjured mucous memlu'ane of the mouth, pharynx, and the intestinal tract does not offer ()])p()rtunity fm- infection. This opportunity is afforded only when (h'strnction of tissue and small wounds permit the entrance of the contagion. Thus for instance Galtier succeeded in producing rabies tlirongh rubbing brain material of ral)i(l animals into the nineons mem- brane of rabbits. According to tlie observations of \'irsehikowsky the rabid virus is destroyeil l)y the gastric juice. _ Very little, or nothing at all is known relative to the s]ieeial relationship of other infectious diseases to milk, as for invlance malignant catarrhal fever, croup of cattle, the blood diseases of cattle caused by spirocha-tes, trypanosomes and piroplasnia, or in- fectious vagiiurl catarrh and infectious abortion. In the presence of infectious vaginal catarrh and contagious abortion the milk secretion is sup]iosed to be diminished. It should be remembered that in such affections the passing of tlie disease agents from the blood into the milk is possible. [That the bacillus of infectious abortion is eliminatets 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 m the early staiics of chronic inflammations of the udder, or after the subsidence of the acute symptoms, and it is then only possible with tlu' aid of certain methods of examination to differentiate such affected milk fi'om ncn'inal. Therefore of special importance to milk hygiene are the clironic inllanunations, and inflannnatory stages in which the 73 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 custard, 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- tococcic mastitis, and in infections with the Bacillus pyogenes, etc. In chronic 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 disc on the yellow to yellowish-brown base, which is composed of leucocytes and coagTilation 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 cream. 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 muner- 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. fibrinous flakes appear (Zscliokke, 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 wliich the affected quarter manifests, as compared with healthy quarters, from the change in the behav- 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 sus])i'cted 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 i)ossible presence of flakes, etc., as should be the duty of the milkers, then the mix- ing of sucli milk 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 (|uarters whicli produce a milk so changed that its alnionnalities can be recognized by its appearance or taste could l)e 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 l)eliavior of the animal, tliaii the veterinarian can by a single clinical examination. Tlierefore 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 piesence of ud- der affections. Periodical examinations of all cows producing certi- lied milk, supplemented by tests of the milk olitained 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 wiiich 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 ]^arenchA^na 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 Schaffei- and Bomlzynski 's examinations the milk from cows affected with mastitis showed the following values: Water Solids. Pat In non-infectious garget 92.8.3 7.17 0.82 In yellow gait 89.34 10.66 1.99 In parenchymatous mastitis 90.26 9.74 2.16 In comparison with healthy milk 87'.7.'5 12.2.5 3.4 Pro- teid 4.01 6.00 4.21 3..5 Milk Sugar 0..53 1.84 1.01 4.6 Total Ash 0.79 0.83 0.97 0.7.5 % P2O4 % CI. 7.35 35.76 19.21 20.0 27.79 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 of the Milk Specific Solids. Pat Nitros; Gravity 1% days 2 " 5 7 O 2 IV- IV. 1 8 O 21 " udder iccovering. ' ' from two affected quarters " from two affected quarters ' ' from two affected quarters ' ' from two affected quarters 1.0314 1.0430 1.0379 7.45 5.15 9.80 11.28 7.69 23.58 15.88 9.66 15.88 20.94 18.18 0.52 0.22 1.95 2.72 1.09 9.30 4.50 2.09 0.i53 4.50 0.97 2.80 enous siibst. 6.17 4.26 2.98 3.. 50 5.74 8.53 5.37 6.74 5.13 5.37 16.65 7.93 Milk Sugar 0. 4.06 4.35 0. 4.68 5.14 2.09 5.14 2.61 2.04 Ash 0.85 0.S2 0.81 0.70 0.87 1.07 0.87 0.85 0.87 0.71 0,91 In most cases the specific gravity is lower (Seel, Mezger, Puchs 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, Puchs 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 resiilts, at the beginning of the affection frequently finding abnormally high or again abnormally low fat contents of the milk. Mastitis. SI The amount of milk sugar as a rule is reduced, and rises only with the api^earanee of recovery. The solids are likewise usually diminished; the fat-free suli^tamc is also, and only becomes increased after i-igns of rciovery have lieen noticed. The amount of proteid coagulable by heat frequently increafes enormously, as compared with the contents of casein which diminishes. Tile ash content on the average is imieased. Eelative to the composition of the ash the data ajipear to 1 c contradictor^'. Although Scol found in I'i ca-^es out of l'^ a diminution of chlorides against an increased quantity of P0O5 Mezger, Fuchs and Jesser oliscrM'd an increase of the chlorine content and a diminution of the phosphoric acid, while Steinegger and Allemann found that the amount of P-O-, C'aO. K^O and llgO diminislics, in gcncial, while the quantity of CI., Xo^O and SO;; increases. Accordin;; to Hashimoto the ash of abnormal milk closely ap|iroaches the ash of blood serum (0./S',c), fonsisting of s.iiMi:! K-.O; 36..544 Na.,0'; 7.44 CaO ; 1.7:W JIgO; 17.:'.SU P2O- and 3::.(\-27'/, CI. The reaction of affected milk is mostly alkaline (Seel, >.re?ger, Fuchs and .Tes-or, Hovlicrg, Auzingei', TOrnst), or more rarely acid (Zschokkc. Henkel, Wy-sniann and I'ctcr, Krnst). The ilctennination of acidity is recommended by Plant as a means for the liiiignosis of udder afl'ectioTis. ludeiiendently from the ilegrce of acidity, the coagulability on tlie a.ldition nf alcohol is frequently considerably increased but not always, and in some cases not coti- stantly. (llenkel, i.'ullniann and" Tronimsdorff, Auzinger). The refractaliility of the calcium chloride serum not infrei|uently suffers cun- sideral.le changes ujiwanl and ilownward. Kipper, Ertcl, Mairliider, Schnnif, Mai and Eothenfusster, Henkel, Mezger, Fuchs and Jessei- found consideralde cdianges in tins respect and proved that the daily variations in the rcfra.tion may I c very great m milk of individual quarters, and even in th,- full milk of an animal. Frequently liowcver t le refraction of the calcium chloride serum sliows no cdiange when i-ornpared witli the milk of healthv animals. ...,.•,, j The -ame variation obtains in the loucrini; of tlie freezinu- point ot milk from atfeeted quarters; tlie values mav be conslderaMy higher than that of healthy milk or on the other hand they may lie lowc. Mmv frequently a high Naliie ,s^niMM|ed (S,-horf, Qniraiid and Laserre, CrisiJO, Bertozzi, Pins), .\rcnrding to Sdinort the el,v trical conductivity is always increased, never normal or lower. .\cc„rding to l.onnema the increase of c-hlorides results in an increa-e of the electrical .-on.hH-tix ity. A elian,i;c in the coiitoiits o\' oi'i,i;iiial I'cnm'iits ai)i>('cir> very early (hiriii.i;' the aCfeclion, toiivtlier with an inn-case of eelinhir elenients, es|ieeially hnicoeytes (Zscliokl«', Bevuvy, Ti-(innns(h)i IT and Rnlhnann), 'and tibrinons Ihib's ( Doane, Knssell and Hoffmann). Aeeoi-dins' to Koning' the increase of the catahise content m freslily obtained niill^ is an indication of tlie affection of the nd- der, provided the colostral period has ])assed. The publications of S]nndlers and Rullmann (who were enabled to obtain ascjiti- eally milked saniides with which to work) and the anthor's obser- vations confirm Konins>''s findinns. The anthor obsiuwed tliat in slight, local affections of a chronic natnre, withont febrile mani- festations, the content of catalase nsnally rnns parallel with the cell content, and it rises when there is an especially marked throwin,"- off of epithelia (presence of tyjiical colostral cells). The facnlty of splitting- np added starch solntion likewise in- creases in milk from affected ndders as e07iipared with that from jiealtliy ndders. There are no observations relative to the qnanti- tativi'"effec1s of peroxydase. Accordin,-- to Weichel the peroxy- dase content of affected milk from an artifically affected o-oat dis- appeared, whereas the healthy milk -ave the Sfnaiac reaction. go Effect of Internal 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 (EuUmann, 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 case is different Avith 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 b)' IBauer 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 slight. The alkaline reaction of affected milk, the altered proportions of mineral salts, at times the passing into the milk of bloody parti- cles, 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 coag-ulation of affected milk also appears to be considerably delayed. Infectious Agents of Mastitis. Nocard and Mollereau, Kitt, Lucet, Bang, Gruillebeau and Hess, Zsehokke, 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, parenchjonatous lesions. The general condition is severely influenced through 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 group of the BaciUns pyofjeves, Sven Wall's pyobacillosis of the udder. The Bacillus pyogenes colonizes with a special predilection in the pres- Siix'pliiciiccio Mastitis. 83 (Mice of streptococci or staphylococci, and in these mixed infections causes severe necrotic intiammations 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 ai'e pioduced hy tuberculosis and actinomycosis, and tliey usually result through emboh of the in- fective agents. They may be of a traumatic origin (actinomycosis) induced l)y irritation with particles of straw, or barley iieards. Furthermore all possible infective agents, as for instance the Bacillus iii-crojiliornx, may be found in inflammations of the uddei% either independently or as mixed infections. Only the more important inl'ections of the parenchyma will lie described here. Streptococcic Mastitis. By far tlie most widely spread type is the strejitococcic mas- tisis, described by Sven Wall as sti-ejitdiiiycosis of the udder. The works of Hergey, (!raandijk, Trommsdurff and Kullmaiui, Kunze, Kussell and Jloll'miinn, Savage, liiihm, and Ernst give ,i;eii- eral information on this condition. '^Flie disease is (>ither s]iovadic or epizootic among the animals of a stable according to the stable conditions. The disease may attain an es])ecially wide distribu- tion when the seci'etion of the alTecteil (|uarter 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 regi-etted, are (juite conunon. Zschokke, Jensen, Bang, and Sven AVall ])ro\-e(l expei-i- nientally that bacteria injected into the cistern ])enetrate even into the farthest alveoli in from '1 to 24 hours. By inoculating with strains of strejitococci of dilTerent ori- gin varying reactions nuiy be ]»roduced in the udder (Bang: Strcp- tocdfci ('(/lit and Streptococci (n/(iI]itococci 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- coiilance 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 auinmis the diseast' conflnes itself mostly to the altered appearance ot the secretion. The result of the disease is that sooner or later the affected jiart of the gland becomes destroyed. Sometimes the streptococci remain for weeks in the folds of the mucous membrane of the eistei'U without infecting the par- euclnnna; in other cases again the entire quarter quickly becomes affected. Unfortunatelv the disease does not often subside even 34 Effect of Internal Influences. tlirougli 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. Lingelsheini). 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 parenchjnua of the udder so that the usual development of the gland during pregnancy cannot 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 Zschokke may be ex])oeted 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 spi'ead of the disease. If, liowespr, there is assiiraiiee that the affected animal or the affected quarter, respectively, is individually milked, and the milkers follow instructions, an attempt may be made liy special frequent milking- (into a jar) to produce a hyperemia of the udder. With this method success can only lie 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 Avhen only a clinical examination is made. This therefore does not suffice in order to eradicate the disease effectively, or to single out the aft'ected 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. Streptncciccie ]M;islitis. 85 Out of '2(10 animals Trommsdorff found IS.G'/c affected, Riilnu 31 .2.j7c out of 16 animals, Russell and Hoffmann found in 188 sam- ples 507o with "streptococci." Savage found similar values (5570- The author examined from April 1, 1907, to November, 1908, l(i97 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 353 190!). No. of animals, 738. Streptococcic cases 301 1910. No. of animals, 597. Streptococcic cases '20') 1911. No. of animals, 876. Streptococcic cases 279 Therefore 20.6; 20.9; 40.6; .34 and 31.8^, respectively, of the animals weie found to be affected with streiitococcic infections of the uddf]-. 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 fr('<|uently be found. Out of 52^ (piarters of animals with affected udders 276, or 52.27, showed lesions in individual quarters. .39.27. "' f'"' cows had tlie disease in one quar- ter, 25.9% showed it in two (piarters, IS. r)7' in three (|uarters, and 16.27' in all four quarters. According to Zschokke out of ()62 alTecte(j (|uarters 193> oceuri'ed in one quarter ol' the aniTual, 211 in two, 109 in three, and 149 in all four quarters. The contamination of nuirket milk with the seei'etions from animals with udder alfeeiions is relatively high. In spite of the fact that proof of tlie mixing of milk from affected udders with nuirket milk is jiossihle only in very pro- nounced cases (ty])ical streptococcic chains with characteristics of animal origin), nevertheless the following results, obtained in examinations, demonstrated conclusively that the secretion from quarters affected with streptococcic nuistitis had been adiled to the whole milk : 1908, in 352 out of 1578 saniples=22^r 1909, in 501 out of 1629 samples=40.5f^r 1910, in 243 out of 1211 samples=20^; 1911, in 432 out of 1273 samples=33.97o The hygienic importance of the affection to the consumers of milk nuiy be illustrated from the following data. I. Hoist, in 1894, had the opportunity of examining in Ohris- tiania four series of affections of acute gastro-intestinal catarrh. T. Four grown persons and four oliiMren out of three families in the same ^tnct l.cMiiriic aflfei'ted four honrs after the ilrinking of milk which originated upon one farm. Those persons who ilrank no milk or only that which had been boiled were spared nilh file r\i-eption of a child who lieiaine affected, althoujjh only slightly, after drinking boiled milk. gg 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 eases also became affected with acute gastro-intestinal catarrh. In this case a milk dealer was implicated, and it was found on inquiry that the milk con- tained secretion from a. cow affected with streptococcic 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 streptococcic mastitis. 4. After the drinking of freshly drawn raw milk four children of the same fainily 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 regvdar 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 streptococcic 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 jiossible 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 casuisties of "milk poisoning" were published by Jakobsen and Weigniann and Gruber. II. In 190.5, .lakobsen observed symptoms in several persons which he traced to the drinking of milk from one ftable. The symptoms were diarrhea, vomiting and fever. Out of 17 perpons, 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 streptococcic mastitis in one animal. The cow was slaughtered and no further cases were reported. III. 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 great abundance. — Trans.] TV. Lameris and Harreveld observed an outbreak of diarrhea among the 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, etc., 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 Tahh II. *SifeK. Ernst, Milh Hygiene. Stre]itcn'iiocie JIastitis. qnaiititics of mastitis streptococci are sufficient for the proJuction ot severe intestinal affections. On December 17 . - ^ .„ proilueers 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. Ihe affection was marked by chills, diarrhea, headaches, and lasted not quite an entire 'lay. The milk constituted the only common food partaken bv 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 capa))le, 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 alfected 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 fre(iiieiicy. 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 necc'ssarily 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 l)(nliug of the milk is not always sufficient to destroy the injurious ])r()])erti('s may be seen from the cases of Hoist and Lameris and van Ilar- 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 Avhicli 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 ])roducts 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. Sonic authors, such as Petruscliln^ 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 saproph^-tic streptococci which contam- inate the milk as a result of unclean milking. This view was also expressed liy the author in iNlay, 190S. and was confirmed by Trommsdorff. Neither studies nor animal experiments have succeeded up to the pr.'sent time in proving the harmfulness of the strei)t(. -ci l)v tluMiiselves. or the relationsliip of the mastitis streptococci to human patho-iviiic strains of streptococci, the animal expcninents Effect 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 oblig-ed to prevent the contamination. Escherieh and Hoist found stieptococei in almost every sample of milk, and Hellens repeatedly isolated them from milk. In 1840 in samples of market milk from Munifh and vicinity the author succeeded in isolating streptococci either by culti- 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 62 ^r- Savage — 17 samples of market milk 100 % 10 samples of market milk 100 % Kaiser — Market milk of Grar 76.6% Briining — 28 samples of Leipsio market milk 9'6 % Easten — 186 samples .57 % Eastles — 185 samples from all parts of England 7-5 % 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- tococci 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- tococci 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 sapropln^tic forms, must be accepted. The formation of acid by the streptococci is sometimes de- scribed as strong (Zschokke, Nenski, Groning, Kaiser, Heinemann, Miiller, Koning), at other times it appears insignificant (Sven Wall, Rullmann). Lohnic classes the streptococci of mastitis with the group of lactic acid streptococci, especially with the group of Streptococci giintheri, with close relationship to the group of Streptococci rosenhacli, 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 intensitv 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 (Tvp. 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 bees ' ' 2. "The action on carbohydrates is practically uniform.' Sireptnccecic Mnstitis. 89 3. ' ' Influencing individual strains relative to their acid formation in the sense of iiKTca'-int; 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 giintheii anil 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 sujiposition that the pathogenic streptococci represents lactic acid bac- teria of the Typ. giintheri which have adapted themselves to parasitic conditions, is sub- stantiated liy the findings, since it was possible in the various strains of streptoeoici to produce transition forms, which correspond to the T]ip. gunlhcri." Therefore from these few examples it may be seen that it is impossible to separate the streptococcus of infectious mastitis from the group of the lactic acid streptococci. Xevertheless it would be a great error to identify the ordinary lactic acid ^'S- i'^- 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, tlie streptococci of sour milk, and others, have a fa- voral)le infiuciice on the nutrition of man, the ne- cessity of their strict identification for control- ling the milk supply is apparent. Although it is not possible to absolutely dif- ferentiate one strain by cultural and biological characteristics, from a culture strain of dilTei- ent origin, nevertheless there are certain morphological characteristics of the streptocdcci in the smears made from sediments, Avhich are sufficiently constant to absolutely warrant the definite assertion that the streptococci in certain positive cases originated in an infected organ, and were not incidentallv leading a saprophytic existence in the milk. _ It has been known for a long time that parasitic bacteria in the animal bodv, under the influence of the animal's protective strength, attaincertain peculiarities of form Avhich thev lose under ordinarv cultural conditions (under certain conditions it is possii.le to cultivate caiisulated anthrax bacilli). Reference is made to the capsule of anthrax bacilli and to the formation of botrynuiy- cotic clumps l)v streptococcic forms. CNmsideration of the question whetlier such chan-es of form in bacteria are developed as protec^ Sediment of milk, one day old, from an udder affected with streptococcic mastitis: (a) streptoconi of in- fectious mastitis, (bl snliscqucntly develcp' d strep- tococci; 1, ■-, 3 and 4, cells t'crn the udder. 90 Effect of Internal Influences. Fig. 18. tive agents against the immunizing powers of the body, would re- quire too lengthy a discussion. The fact should suffice that strep- tococci originating from affected udders almost invariably show signs of such transformation. It is not intended to assert that a steptococcus 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 streptococci which are present could not undergo changes of form which under certain conditions simulate the forms of "animal" streptococci; but for normal conditions of milk inspection the morphological characteristics of animal streptococci offer certain definite appear- a n c e s of recognition which have always been proved by control tests made in the respective stables. These characteristics are the following: The streptococctis 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 Eabe.) A fine capsule is formed Sediment of market milk in which the typical animal arOUnd tlie "animal" forms of streptococci (a, b, c) make possible a diagnosis mil-V c.+-ro-n+nr>rv/i/ii ittIt^^It that the milk contains the secretion of an animal af- iiiii-H tell ep LULOLCi, WUICU fected with streptococcic mastitis in spite of the oc- ia qomptimpa mnro it currence of other forms of streptococci (d and e). i& bUmLUmeb mOie, dL other times less pro- nounced. This sometimes swells to a broad mucin capsule (com- pare Lingelsheim on streptococci, Wassermann-Kolle's Hand- book of pathogenic micro-organisms III, pp. .309 and 310, and Sven Wall, p. 29). The endococcus, especially in short chains is spherical or swollen to a club shape. With slight practice one almost invariably succeeds in dis- tinguishing, by one or the other given characteristics, the "animal" mastitis streptococci from streptococci which have gained access to the milk accidentally (even though they may also possiblv be de- scended from "animal" mastitis cocci). In tliis way the author succeeded, from April, 1907, to Novem- ber, 1908, in demonstrating by the aid of smears that secretions from cows with streptococcic mastitis wei-e mixed with market Streiitneoccic Mastitis. 91 milk. < )iit of 1840 microscopically examined samples 336, or IS. 1.1(3 /r showed the pre.-,onco of such an infection. In Dl cases, or 4.!)4.j'^o the changes were not very pronounced ; later control however proved that milk from cows affected with yellow iiaryct had been mixed with these shipments. 18.26% +4.04:j';'o = 23.20.j7o, proved contaminated with 8tre])tnff)ccic pus out of 1840 milk samples. ]\Iiiller intended in his work to distin,:^iish milk streptococci, es]iecially the streptococei of mastitis, from strains of streptococci Itathonenic to man. In confirmation of the work of Xieber, Fischer and Beriier, ^Miiller came to the conclusion that the Fig. 19. reeon'iiition of milk strej}- toeoeci pathou'enic toman is impossilih'. Althou.syh milk stre])tococci as a rule coai^ulaie milk some- what more quickly, there are also strains which coagulate milk somewhat moi'e slowly, and strains "which dissdive the blood colls in Schottmuller's bh)od agar, and these in their agglutination value stand \'ery close to the pathogenic strejitococci of man, that is, they ag- glutinate even in dilu- tions of tln' serum of 1 :4(I0— 800. At the same time several of the abso- lutely ]iathogenie strains fail to give any agglu- tination, and other ap- ])arently saprophytic va- rieties give a higher ag- glutination value. Bau- mann proved that there is no uniform agglutination value of the individual kinds of strejitococci, and that spontaneous ag:;lutina- tion fre(|uently appears in tests of their cultures. Together "with Ilorauf, the author found that mastitis strains show similar characteristics on Schottmuller's blood agar to the less ])athogenic strains of man, a fact which has recently been con- lirined bv (Jminder. I.iiigel>heim makes the statement that stre]itn- c(.cci ]ii'oducing toxins are always obtained from subacute and chronic ]irocesses. Acid foi-mation and milk coagulation are common to the entire cdiment of red milk. Many red blood corpuscles, ^(■\eral polynuclear leucncyr^s and colnstral cells. Strcttococciis brczis with capsules. 1 X li'OO. 92 Effect of Internal Influences. group of pathogenic streptococci. Of the pyogenic strains of man, according to Andrewes, the Streptococcus pyogenes and the Strep- tococcus mitis produce acidity without coagulation. Sven Wall proved these characteristics from the mastitis strains isolated by him. According to Adametz, the mastitis cocci sometimes coagulate very intensely, the same as is the case with the streptococci of enteritis of sucklings (Petruschky). The fermentation in various sugars using Gordon's bouillon mixtures, varies greatly with the different pathogenic streptococci and milk streptococci, so that the possibility of differentiation by this means is quite impossible, which is likewise the case by testing their virulence on small test animals. Pathogenic ' '^' ■ strains may at times show great variations of viru- lence, while according to Heinemann strains of the Streptococcus lacticus may become virulent by passage through rabbits, until they will produce changes in rabbits which correspond in their ap- pearance, extension and character, to those caused by pyogenic strains re- cover ed from man. Through their action on animal bile, or on sodium taurocholate, Mandel- baum differentiates the Streptococcus mucosus and Pneumococcus from Streptococcus pyogenes and other streptococci (Neufeld, V.Levy). The author used the mastitis strains he had on hand on cattle, hog, horse and chicken bile, but failed to observe either a clearing of the culture media or an influence upon the form and appearance as shown by the microscope. The establishment of the "virulence number" through phag- ocytic experiments also fails to yield the desired result. In short up to the present time the absolute separation of culture strains of varied origin, the differentiation of saprophytic streptoccoci from mastitis streptococci, and these from pathogenic streptococci of man has not been successfully accomplished. ' We liave, however, in certain morphologic indications, for instance Sediment of milk from an udder wifli acute inflammation .Short foi'ms of streptococci. 1 X 1000. Strept. ric :Maslitis. !);i :x m ^^^IP ^•"■•^j ^ J the cross-position of tlie segments, the capsule-like covering and other characters, a way of distinguishing- streptococci originating in the udder of an animal from such as have subseciuently gotten into the milk. If these distinguishing signs are present then smears from the sediment of market milk permit the deduction that secre- tion from an affected udder has been included in the milk. If, on the other liand, these signs are not present in the streptococci of the milk, it cannot be asserted that the milk is not contaminated Avith the secretion of affected udders. Although it is not known what factors ^'S- 21. (streptococci, toxins, in- flamiiiatoiy products) convey the uuwholesome- ness to the milk, and al- though in spite of the fre- quent occurrence of mas- titis injurious effects re- sult Avith relative rarity, nevertheless the secretion from udders affected with streptococcic mastitis, and mixed milk wliich is (■(intaiiiinated with such seciction should be con- sidered capable of im- pairing the human health, since 1. There are known cases in which severe* dis- turbances of health vo- Rulted from the ingestion of such milk. Ll. T h e investiga- tions of streptococci scieutificallv justify the susi)icion of harm arising from their ingestion. AVhat are the conditions of the mastitis streptococci among themselves? Formerlv a Sfreptocnccus hrevis and a Streptococcus lonnns were distinguished, but it was shown that these distmgmsh- ino-' features were not absolute (Staeheli). The differences of the in- dividual strains and the forms of their growth m culture are asin- (M.n-^tant as their pathogenicitv, acid f'2 the Streptococcus loin/us; in 47 the infective agent was recog- niz<'d in the form of a diplococr-ns. The 47 quarters Avith diplococci liad as a rule a very small leucocytic numher. In values of over 2.0, longer coccus-chains were always ohscivi'd. .'52 quarters out of the 47 had 0.5 :1000 leucocytes 12 quarters out of the 47 had 1.0:1000 leucocytos 3 quarters out of tlie 47 had 2.0:1000 leucocytes In the 55 cases with St rcplococcus lircris the change in tln' leucocytic number vaiied to a greater extent. In 18 it represented 0.5:1000 or In 14 it represented 1.0:1000 or 25.47',. In 8 it represented 2.0:1000 or 14.55'/. In 3 it represented over 2.0:1000 or 5.45^ ■ >-. I ■> /r . ( . oi oor' f. In 12 it rei)resented 5-20 and more :l(H)(t or 21. S: The 3)2 longus-cases were divided as follows : Leucocytic Quantity. Number of Ca-cs. Penciitagc. Under 0.5:1000 1 3,.1J5 Tip to 1.0:1000 1 3,. 125 up to 2.0:1000 3 I). .375 up to 5.0:1000 3. <).;175 up to 20.0:1000 3, !) .',75 up to 100 and more:1000 21 (55. 625 In other words : lu tcHcncj/tic (/uaiifitics T']i to 0.5, 6.1. n(V,; showed .".".()'~; brevis, i.OO^'^ Dipl. longus V[i to 1.0, 44.4(1' ; showeil "'1.!'' • brevis, I^.TiK'r Dipl. longiis T'l> to 2.1), I'.li.'i''; showed i'4.7' r luevis. 17. lU-^^ Dipl. longus Tp to 'i.ll, O.OO'.r showed ."iO.O':;- brevis, .^0.110'-^ Dipl. longus I'p to 20.0, and more 0.00% showeil 33.0',; brevis, 06.60',; Dipl. longus The leucocytic values will be taken up again later in the dis- cussion of the '"'Trommsdorlf" test. From this talmlation it may be seen that the length of the cliains actually grows with the increase of leucocytes, or with the amount of sediment. In high leucoe:si:ic values and short forms of the infective agents, the latter are frequently present in exceed- inglv large qantities. "The opinion that the form of the streptococcus represents an adaptation to the energy reaction of the respective animal and or- '-•an is therebv substantiated especially when the streptococci are ()5 Effect of Internal Influences. found in tlie secretion of one and the same part of the udder of a cow at different times. In the same way it is impossible to establish rules for definite differentiation of the streptococci of the yellow garget among them- selves through the study of their morphological relations, by com- parison of their biochemic characteristics or the pathogenic viru- lence of individual strains, since the acid production and acid susceptibility which are present in mastitis streptococci at first may be easily changed by artificial means, and individual strains have proven the possession of stronger, others a weaker pathogenic action for test animals ( Groning, Sven Wall ) . The author does not desire by any means to establish a theory of unity for mastitis streptococci. To be sure there are marked differences in the various strains, especially in regard to the pro- duction of clinical symptoms, which cannot be attributed alone to the variation of virulence, and to unequal resisting powers. It is possible that with the aid of newer methods of differ- entiation (blood media, etc.) it will be possible to establish a fun- damental type of mastitis streptococci in strains freshly cultivated from animals. Even if with the continuance of cultivation new characteristics, as for instance heniolytic properties, may be acquired by the cultures, and the earlier characteristics become lost, the characteristics acquired by the respective strains of streptococci in their former growth may remain constant for a sufficient length of time to permit the establishment of the type of varieties, as has already been the case with the streptococci of man (Petruschky, Schottmiiller, Baumann, Schulze and others). Enrst, Grminder and others have demonstrated that the mastitis streptococci mostly correspond to the mitior sen viridans or mucosus hom. group, respectively. Based on the grounds previously described, milk hj'gienists, bacteriologists, children specialists and veterinarians sometimes more and at other times less imperatively have demanded the ex- clusion of cows with streptococcic mastitis from the production of milk (Jensen, Weigmann, Eievel, Sven AVall, Ruhm, Trommsdorff, Seiffert, Ernst and others). This requirement is natural from the hygienic standpoint, but its practical execution is rendered very difficult by the remarkable prevalence of the disease, and as a matter of fact as long as the general control of production and the examination of milk of indivi- dual cows are not required a thorough enforcement cannot be hoped for. For the present the exclusion from the market of all milk Avhich shows changes in a recognizable way, as for instance through a collection of yellow sediment, should be considered satisfactory. At the same time from an economic standpoint only milk from arfected quarters should be excluded, while the sale of milk from healthy quarters should be allowed. Udder TubercuL 97 TUBERCULOSIS. Occurrence of Tuberculosis in Cattle. Tuberculosis of the udder in cows appears with relative fre- ([ucncy, corresponding to the frecjuent occurrence of tuberculosis in cattle. Tuberculosis in the udder is manifested in different forms, the circumscribed, lobular, focal tuberculosis and the diffuse tuber- FiL'. 22. Tuberculosis of the udder. Proizrpssive miliary form. culosis extending over and infiltrating the entire udder. Two of the different forms may be present at the same time in the organ, and from one form through accentuation of the infection the other forms may result. ("linicnlly tuberculosis is manifested by nodular swelling or liai'd ('iilaii;eiiient of the affected quarter, and with enlargement and ))aiiile Berlin 61 Buege 6 Halle 33 . 3 Petri 64 Berlin 14 Berlin 30.3 Market milk Berlin 55 . 5 Dairies under veterinary control . . 0. Danish milk 38 . 5 Leipzig 10 . 5 [The percentage of tubercle bacilli found in the milk supply of large cities in this country has been accurately determined in only a few instances. In 1907 Anderson proved that in Washing- ton, D. C, 10.7% of the dairies supplied milk containing virulent tubercle bacilli, Schroeder found 7.7% of the 26 dairies examined were distributing infected milk to Washington, D. C, Avhile still later Mohler showed that about 3% of the 73 samples of milk ex- amined contained tubercle bacilli. The apparent discrepancy in these results may be readily explained by the fact that during" the last 6 years strenuous efforts have been carried on by the Bureau of Animal Industry to eradicate tuberculosis from among these herds, with the result that in the District of Columbia the number of tuberculous animals has been reduced from 18.8% to 1.2% in 1914. Hess has found that 17, or 16%, of 107 samples of milk dis- tributed in New York City contained virulent tubercle bacilli, while Campbell made extensive investigations of the occurrence of tubercle bacilli in the market milk of Philadelphia, and found 18 or 13 . 8% of the 130 samples examined to contain living bacilli of tuberculosis. — Trans.] Under What Conditions Do Tubercle Bacilli Enter the Milk? The infection Avith tubercle bacilli is natural when the animal is affected with tuberculosis of the udder, or may occur indirectly when through contamination of the udder Avith feces in pulmonary or intestinal tuberculosis, urine or vaginal secretion in kidney or uterine tuberculosis, or with infected straw, tubercle bacilli" are brushed off from the soiled udder into the drawn milk, or when in Infectiousness of ]\Iilk. 1Q\ open tuberculosis of the lungs the bacteria get into the milk through the air or straw. As early as 1869, prior to the discovery of the tubercle bacil- lus by Koch in 1882, Gerlach proved the "infectiousness of milk from highly tuberculous animals through feeding and inoculation experiments. This Avas also emphasized bv Ziirn, Klebs, Sommer, and in 1880 Ijy Bollinger, who first pointed 'to tlie fact that the milk of a tuberculous cow in which the udder is not noticeably affected may contain tubercle bacilli. The same i-esults are shown by the works of Stein, Bang, Hirschberger, Ernst, Schroeder and Fiorenti, who succeeded in producing tuberculosis in test animals with milk of tubei'culous cattle, even though there was no udder tuberculosis present. Milk from tuberculous uddei-s always lias l)een proved to be esijccially dangerous (May, Bang). If sjjecial care weic exercised in milking, it net infrequently happens even in extensive, generalized tul)erculosis that the in- oculated animals remain well; thus Xocard from injecting milk of 54 cows affected with generalized tuberculosis succeeded only in 3 cases in producing inoculation tuberculosis. Therefore it ap- pears that in sjiite of a generalized tuberculosis when udder tuber- culosis is not i)resent, tubercle bacilli are not always excreted Avith the milk; the possibility of elimination however, that is, that the milk of such a tuberculous cow nuiy contain tubercle hacilli, should at all times lie given consideration. Ts milk liable to be alTected wlien tulieicnlosis cannot lie clin- ically demonsti'aleil in sns])ecte(l cows, or when they apjiear healthy and yet react to tuberculin? Are tubercle bacilli eliniinatc(l only with the milk from aninuils affected with tuberculosis of the udder, or also in cases where the udder is not affected by tubercnlo>i> .' These questions may be answered at the present time with grent certainty, namely, that tubercle bacilli of cattle are eliminated with the milk as a rule only in animals which are affected Avith tulierenlar mastitis. This question is of especial interest in the eradication of tuberculosis in the dairy herd, since it is avcU knoAvn that calves and hogs are highly susceptible to the tubercle bacillus of cattle. It Avill be advisable therefore to refer to the more important publica- tions on the elimination of tubercle bacilli Avith the milk, before entering into the question of the harmfulness of such for man. Delcpiiio, Ttavencl. Eabinowit?ch and Kempner, Gehrmann, Geliniiann and Evans, Monssn ami Aloliler obtaineil positive results from milk of animals not rlini- cnlly ad'ei-ted, bnt reacting to tlie tuberonliu te'^t, through inoculating or feeiling of test aniiiKils. Other investigators, as Atartel and Guerin, also Hirschberger, aimed to solve the qiicsfion liv inoculating the milk of slaughtered animals or glandular substance from udders of reacting animals. Their work also frequently gave positive results. A!J of Hicxf authors thcr( forr, ciniclmh- with iinat rrrtaintji that tubercle iacilli mni/ he eliminati (1 uilh the mill: crrii from iinimaJs wliich are not clinicallii aifccted tcith tu- b( nulii\i.i. Other views are snpporteil by A-c-hcr, Afuller, Ostertag, Stenstrom, ArrWciney, T'li^ch and Tlr-^slrr as the result of their negative findings, namely, if the experiments were conducted under the iiio^t painstaking requirements and all contaminations through 202 Tuberculosis. infecteil straw, etc., were avoided as nnieh as possible, they failed in spite of numerous ex[]eriiTients in proiluc-ing tuberculosis with milk from a tuberculin reacting animal, and frequently not even with the milk from an animal clinically affected, but free from tuberculosis of the udder. From tlie standpoint of milk hygiene the fact is important that in the work of tuberculosis eradication by the agricultural societies the examinations for tubercle bacilli in the mixed milk of individ- ual herds were mostly negative after the clinically affected tuber- cular animals had been eliminated. According to the works of Muller and Hessler until July 1907, 2,949 samples of mixed milk of individual herds were examined ; all of these herds were sub- jected to the Siedamgrotzky-Ostertag method of eradication. From 30 to 200 cows participated in each test and 156 herds gave milk free of tubercle bacilli. As eliminators of tubercle baciUi were found : Two cows with udder tuberculosis, 8 times each. One or more cows with tuberculosis of the uterus, 16 times. One or more cows with tuberculosis of the uterus, 6 times. Once kidney and uterine tuberculosis. Once pulmonary and intestinal tuberculosis. Once a cow whose saliva contained tubercle bacilli and 19 times open pulmonary tuberculosis. In five positive tests there was no clinically demonstrable form of tuberculosis, and the subsequent tests of immediately drawn con- trol sanii)les remained negative. These five cases were observed in the Ijeginning of the eradication work. The remaining 2,793 milk samples were free of tuberculosis in spite of the fact that among tlie animals of these herds there were surely a great number which would have positively reacted to tuberculin tests. The five cases observed at the beginning of the eradication work, in which the milk contained tubercle bacilli, although clinically open cases of tuberculosis could not be found on stable examination, are explained by Hessler in that the milk became contami- nated with particles of the feces from pulmonary cases of tuberculosis, which had not yet developeil clinically. This is also suggested by the smaller number of bacilli found in the milk. Tubercle bacilli therefore occur in the milk in great numbers when animals with open tuberculosis, and tuberculosis of the udder stand in the stable. Milk from animals which manifest their tuber- culosis by a positive tuberculin reaction, will usually be free from tubercle bacilli. Such cows belong to the least dangerous class. Nevertheless the investigations of Eabinowitsch, Kempner, Eav- enel and others, who obtained positive inoculation results with milk from reacting animals, prove that such milk may at times contain tubercle bacilli in small numbers. Ordinarily however this will not be the case, and the milk of such animals may, as a whole, be considered free from tubercle bacilli. Therefore it appears evident that under present conditions of milk production the ingestion of tubercle bacilli with milk is possi- ble at almost all times. Tubei-ple Baoilli Typf>. 103 What Danger Threatens Man Through Ingestion of Milk Which Contains Bovine Tubercle Bacilli? In order to answer this question it is necessary to refer to the (lov('l(i])iii('nt of tuberculosis in man, and to consider the fac- tors which arc nccessai'v for an infection of his body. Th('s(> factors in addition to the toxicity of the infective agent, and tlic quantity in whicli it has the opportunity to enter the body, fine membrane with wart-like prominenc<'s dev(do]is proliferating downward, or a membrane^ of tissue-paper thick- ness results; the bouillon is ]M'obably neutralized and finally lieconu's alkaline. The bovine tubercle bacil- lus is as a rule of greater toxicity for smaller nuimmalia. Kalibits develop through intra- venous injections of the bacillus (O.OOl gm.), a generalized tu- berculosis from whicli the ani- nuils succumb inside of three weeks. When 0.01 gm. is in- jected under the abdominal skin, it i)roduces in a short time, gen- eralizeil tuberculosis. Cattle succumb readily to Typ. Humanus. The giowth is a luxuriant, uniformly thick and wrinkled membrane, which proliferates on the wall of the tube. TIk' growth is the same in b(millon: the dei^ree of acidity of the bouillon is usually at lirst diminished, later increased. 0.001 gm. of bacilU of the human type intravenously in- jected produces after mouths only a chronic form of tuberculo- sis (joints, kidneys, lunu's, testicles). The injection under the ab- dominal wall produces only local lesions. Inoculated into cattle the liacilli of the human type (0.05 gm. subcutaneously), produce only slight or no pathogenic ac- tion. The process remains local, and extends only to the 104 Tuberculosis. infection Avitli the typus bovin- us, from an extensive form of tuberculosis. Guinea pigs die more quickly from an inocula- tion with bovine tubercle bacilli than from an inoculation with the bacillus of human type. neighboring glands ; a great healing tendency prevails. Intravenous injections of 1 mg. of the typus humanus into the vein of a mouse will show it to possess a greater resistance than when inoculated with the typus bovinus. In the last 10 years about 2000 strains of tubercle bacilli from man and cattle have been cultivated and studied. In these studies even further differences were found which, however, are not as constant as those given above; for instance, the bacillus of the human type in glycerin bouillon cultures is delicate, slender, slightly curved, and of beaded staining qualities, whereas the bovine strain is regular, plump, thick without granular differentiation in staining, and frequently with swollen ends. The pigment formation on glycerin potato is more typical of the human type than the bovine type. The former when placed on serum in hermetically sealed glass tubes remains viable for twelve months, the latter for over a year. Contrary to the views of many investigators of tuberculosis, Nocard, Hueppe, Von Behring, Romer, de Jong and others support the theory that the tubercle bacillus adapts itself to the infected animal and becomes transformed as a result of its environment. Eabinowitsch, Dammann and Eber have also supported this trans- formation theory. The latter especially attempted to prove by ex- tensive experiments and investigations that Bacillns h}nna)U(s, by passage through cattle, changes into the bovine type. This question however appears at the present, to be decided in favor of the stability of the bacillus. It has at least been shown with six various strains of the human type, that in passage experiments through 2 to 7 cattle, in from 247 to 512 days, the character of the bacillus was not changed (English Commission and Weber), 'and that bacilli of the human type by eight subsequent passages through goats, in .516 days, and by four passages through cattle in 685 days, were not influenced in their typical characteristics. The immunization experiments which were undertaken with the bacillus of the human type on cattle showed no changes whatsoever in the human type after the pres- ence of the bacteria in cattle for a year and seven months (Baldwin) in spite of their propagation in the udder of the cow. The same results were obtained in three experi- ments by Weber, Titze and Joern, who allowed the bacillus of the human type to exist in the body of cattle for two years and one month and for two years and six" months. Eber's experiments found no confirmation in the Imperial Board of Health; the experiments however are being continued in strict co-operation with Eber. On the contrary it is shown that the bovine bacillus constantly retains its characteristics within the human body. From a boy who was affected since his second year with tuberculosis of the fourth digital bone of his hand, it was possible during surgical interference to obtain material from the same place at five different times, during his age from 8 to 1,3 years. The in- fection was caused by the bovine bacillus. In spite of their existence for ten and a half years in the human body these bovine bacilli had retained their characteristics. A marked influence in their virulence was manifested, however, since the bacilli, from the second operation, in quantities of 2 mg. could no longer kill rabbits even after intravenous inoculations. From the sub- sequent operations it was found that the virulence was again increased. Griffith obtained the same results with bovine cultures from lupus from which the bacilli were isolated six months, two and three and a half years, respectively, after the first examination. It is true that the virulence was several times lower than is or- dinarily the case with the bovine type; the other characteristics of the strain however Transmission of B:ivine Tuberculosis. 105 were tenaciously retained. In one of the cases the bacillus persisted in the human body for ISij years. Passage through rabbits and cattle again increased its virulence. Al- though through animal passage a change of the virulence is possible, nevertheless this change results only inside of the borders of the type and in the direction of the type. The bovine bacillus thiTcforc does not pass into the human type, nor the latter bacillus into the bovine tyiio. ( )iily a brief statement will be made relative to the so-called atypical strains. It has been demonstrated that there are cultural strains which cannot be classified as belonoin.a,- either to one or the other type (Kossel, Weber and Heuss, Lydia Rabinowitsch, do .Tout;- and others). These strains proved to be mixed cultures of both types. In the same person not only mixed infections of both types may exist in the affected organs, but also a double infection may occur in such a way that in one ort^an the Tjipns humanns. and in tlie other or^au the Typus bor'nnis, may he found in pure culture (Weber, Weber and Tautc, Griffith, Park and Krumwiedc, Steffenha.cfen). In 1901 Koch explained at the International Tubercul(*sis ('on<;ress at London, that tuberculosis of man is produced by a tulx'rcle bacillus which differs from the bovine tubercle bacillus, and expressed himself as opposed to the ncncial prevailin.s;- opin- ion of that time, re.nardin.ij: the s'reat dani^cr of tlie cattle tubercle bacillus for man, and as bclievino- tJuit the transmjssibility of bovine tubercidosis to man was so slight compared with the dan- ger which threatens man from tuberculous human beings, that its practical ini])or1auce was negligible. Althougli Koch's statement cannot stand in tlie directniv^s of his declaration, nevertheless at the ])resent time it is generally accepted from the above mentioned dilTerential characters, tliat marked differences exist between the bacillus of l)ovine tubei-cn- losis and that of man, and it is a fruitless work to disjjute ^ybether thev are dilTerences of varieties or peculiarities of the different strains, which lead to the variations, if we accei)t the fact that the differences of the strains are obstinately retainiMl. The results are of especial value in ditt'erentiating the two tvpes of tuberch^ bacilli. In association with Shiitz, Koch nnder- t()ok some experiments to establish points of difl'erentiation. Nineteen calves which were infected intravenously, subcu- tanecmsly, intraperitoneally, by inhalation or feeding experiments with the Bacillus Inimainis. showed no manifestations of disease, in- ci-e;!se(l in weight, and on autopsy conducted several months_ after infection, showed only caseous purulent changes at the point of inoculation. On the "other hand, after the inoculation of bovine tubercle bacilli, severe febrile symptoms and extensive tubercn- h)sis, esi)ecially of the lungs, liver and spleen resulted. The same results were obtained from the experiments of Kossel, Weber, ITeuss. Bacilli of the human type were retained in the regional lymi)h glands ; the changes induced by them gradually retrogressed, whereas infection with the bovine type of the bacillus led to a pro- 206 Tuberculosis. gressive tuberculosis. IiTlialation and feeding experiments showed tlie sliglit virulence of the human tubercle bacillus for cattle. In the experiments of Noeard, Meyer, Calmette and Guerin and Zwick, the inoculation of tubercle bacilli of bovine origin into the milk ducts resulted in a tuberculosis of the udder with rapid emaciation of the animal, terminating in death ; whereas the bacilli of human origin produced only a passing inflammatory irritation, and an interstitial atrophy of the udder. Calves which nursed on these latter infected udders remained healthy (Zwick and Maier), or on the other hand (in one case of Zwick) intestinal tuberculosis, with tuberculosis of the mesenteric lymph glands, developed. At autopsy undertaken 20 weeks after the infection, the udder of the cow showed atrophy with miliary tuberculosis, without however typical tuliereulous changes in the regional lymph glands. From these results the conclusion may be drawn that tubercle bacilli of human origin are only very slightly dangerous for cat- tle. It should be considered however that occasionally after artifi- cial infectious the bacilli may persist in the infected region, Avith or without marked local or at times even generalized changes. Calves may develop intestinal tuberculosis or tuberculosis of the mesenteric lymph glands as a result of ingesting a large amount of tubercle bacilli of the human type. Almost the same relation exists in man towards the bacillus of bovine tuberculosis. The principal dangers threatening man are through the possibility of infection from affected human beings, and less so to the possibility of infection with diseased products of animal origin, as for instance milk. The possibility of tuberculosis infection through animal products is presented with remarkable frequency, as may be seen from the above statements; still the rarity of infection with the bovine type is quite striking. Hogs which become readily infected with the bovine type are very frequently af- fected by the ingestion of skimmed milk containing tubercle bacilli. In northern Ciermany some of the herds show an infection of .50-60, occasionally even up to 9(1'/,. The experience at the tuberculosis eradication stations indicated that by the elimination of cattle affected with open tuberculosis a marked reduction was obtained in tuberculosis of hogs, and that this measure in association with pasteuriza- tion of the skimmed milk, oifers a certain remedy against the spread of tuberculosis of hogs. The same opportunity which is afforded hogs to contract tubercle bacilli from the feeding of skimmed milk, would apply to man. The relative infrequeney of the infection of man with the bovine type of tubercle bacillus is not the result of a milder virulence of the bacilli but is due to the previous boiling of the milk. Convincing observations have also been made on this point. However before entering into a discussion of these, it will be advisable to illustrate further the possibilitv of infection for man from the standpoint of the port of entry, and also show the relative condition existring between the necessary infective quantity of bacteria and the establishment of the disease. Iiiaesticin Tuberculosis. 107 The development of the affection depends on the most varied conditions, on the quantity of the introduced virus, condition of the port of entry, general resistance, etc. Frequency of Tuberculous Infection Through the Alimentary Tract. If the lesser virulence of the bovine type for man, as compared to the human type, is left out of consideration, which fact is con- sidered satisfactorily proven, the experiments of Ostermann, Schroeder and Cotton show what great quantities of infectious ma- terial are necessary in order to produce tubercido'sis by ingestion. Schroeder and Cotton fed milk artificially infected with tuber- cle bacilli, and proved that infected milk which invariably produced tuberculosis when inoculated intraabdominally in 5 c. e. doses. could be fed for 30 days without causing the disease in the ex- perimental animals. The dilutions were prepared (1) by adding one platinum loopful of a cloudy su!^- pension of tubercle bacilli to 10 c. c, of niillc. (2) liy adding one loopful of the orig- inal suspension to 111 c. c. of sterile water, and of this dilution one loopful was placed into 10 c. c. of milk, (3) by adding one loopful of the original suspension to mil c. c. of sterile water and of this dilution one loopful was placed into 10 c. c. of milk. It was not possible to produce ingestion tulierculosis with either the second or third dilution during the perioil of the experiment, although the dilutions were not as high as they occur in the milk of tuberculous animals (with the I'xccption of tuberrnlosis of the udder). Ostermann liy comparing the averago number nf tulicri'lc bacilli in cow's milk with the minimal d(»se iH'ccssary for produciuu' ingestion tuberculosis in guinea pigs, rabbits ami i^dats, came tn the conclusion that an alimentary iiirci'tioii is exceedingly rare. NevertlieU'ss the (hmger of an alimentary infection with bovine tubercle bacilli, even in high dilutions ol' the tnbercnlons material in market milk, cannot be disregarded. Tlie danger of infection to wliicli small children are exiiosed from the ingestion of food (without attempting to distinguisli "lio- vine tuberculosis" from "human tubercuh)sis") is best illustrated by the clinical cases and also tliose cases of intestinal and mesen- teric tulierculosis which are found on autopsy. Edens, from October 1, 1904, to September .10, 1905, found 1:2^;, and from this time until September 30, l!)0(i, 13. (i^^ of the bodies of children which he autopsied at the ages of 1 to 15 years, affected with primary intestinal tuberculosis or tuberculosis of the mesenteric lymph glands, whereas in man from 15 to 19 years of ag(> only '.IS'/i- ami '2.6 ^'c. respectively (all autopsies), showed the disease. The intestinal tract of children appears therefore to be a prominent port of entry for the tubercle bacillus, which is also jiroven bv the works of Orth, Henke, Chiechanowski, Hamburger, Nebelthaii, Lubarsch, Bruning. Fibiger and Jensen. Symes and Fischei-, Price and Jones, Kingsford, Harbitz, Oo^ia, Edens, A\'air('nei- and Heller, who demonstrated primary intestinal tubei- J 08 Tuberculosis. culosis in varying proportions, up to 47.6% of the tuberculous children. The frequency, however, with which tubercle bacilli actually pass through the intestinal wall without producing demon- strable changes in the intestines and mesenteric lymph glands cannot be stated. The intestinal tract may be the avenue of infection without itself or its regional lymph glands becoming in- fected. The percentage given above should therefore be higher. The works of McFadyean, MacConkey, Harbitz, Weichselbaum, Bartel, Eosenberger, Eabinowitsch, Ipsen and others offer proof for this contention, as they mention cases in which apparently healthy mesenteric lymph glands contained tubercle bacilli which although appearing to be in a latent form at the time of finding, produced tuberculosis when inoculated into experimental animals. It appears also to be proven experimentally that through the feeding of tuberculous material tuberculosis of the lungs may develop without the presence of intestinal tuberculosis or tuber- culosis of the mesenteric glands (Bartel, Bongert, Kovacs and others). In this regard the question may be raised as to whether there is any possibility of the tubercle bacilli working up from the intestines into the esophagus, and into the buccal cavitj^, from which inhalation tuberculosis could result (Uffenheimer, Dieterlen). This objection would not enter into consideration for the pur- pose of milk control, since it is immaterial for the hygienist work- ing along practical lines, whether the infectious agent causes dis- ease in the body by way of the circulation or through inhalation. In this instance it is only necessary to keep in view preventive measures, which should completely prevent the body from com- ing in contact with producers of the infection. Alimentary Infection of Man With Bovine Tuberculosis. After the supposed cases of transmission of the bovine tuber- cle bacillus cited in former years failed to withstand critical observations, Koch at the International Tuberculosis Conference,, lield in Berlin, in 1902, urged the following up of all cases of established tuberculosis of the udder, the determination of how long the disease persisted, who consumed the milk and milk pro- ducts from these cases, whether the milk had been boiled and whether the respective persons became affected with tuberculosis. This request was fruitful of results, and in 1910 Weber pub- lished the results of his compilation investigations, whicli were carried out l)y the aid of official statistics from Prussia, Bavaria, Saxony, Wurttemberg, Baden and Hessen. The investigations extended over the time between the be- ginning of 1905 to April, 1909; the investigation of some of the individual cases however is still being continued, since in the chronic courses of tuberculosis it must be considered that the Bovine Tuberculosis in Man. 109 results of infection with bovine tubercle bacilli may under certain conditions only manifest themselves after years have elapsed. In the given period 113 cases were reported, of which 68 were from Prussia, 14 from Bavaria, 6 from Saxony, 6 from Wurttem- beri;-, 10 from Baden, and 9 from Hessen. At least 628 ])ersons came under consideration in the inges- tion of such milk, possibly even more, since at times only the term "family" is designated, and the milk was not infrequently deliv- ered to dairies with a large patronage. These cases were not in- cluded, although evci'y person is exposed to an infection who par- takes of such milk and dairy products. In the case of 9 persons no age is given; 2S4 were children, and .'iSf) adults. The value of the individual cases must of course be .iudgcd in different ways. In 44 cases it is stated that the milk had been consumed only as an addition to coffee, or mixed with milk of healthy animals, or the data were otherwise not accurate. Of es])ecially great interest are those cases in which it was emphasized that the milk was consumed in a raw state, unmixed, mixed with milk of only a fi'W cows, or in which siieh milk was nse(l in the pi-eiiai-ation of l)utter, buttermilk, sour milk, or had been consumed I'oi- a long period. In such eases treineiidous nmn- bers of tubercle haeilli must have been taken into the digestive tract. According to Bang and AVall the milk from tuberculous udders may retain a normal appearance for months, lieing used as food without any objection, and yet such milk contains millions ot" tubercle bacilli. Bang found in smear ])i-eparations of such milk, in a single field as many as I'OO bacilli. In all ()9 cases were reported, in which it was stated with cer- tainty that raw milk of aninuils with udder tuberculosis, or pro- ducts prepared from such milk, were consumed. The milk was taken for a longer or shorter time, in large ((uantities, by If)! children, 200 adults, and 9 persons whose age was not mentioned. These persons are divided by Weber according to the result.^ of the investigations, into four groups, namely: 1. Cases, in which an infection occurred of a bovine type. 2. Those in which a suspicion of an infection exists, but on account of insufficient bacteriological examinations has not yet been determined. r!. In arfecti(His in which the bacteriological examination i-elative to the suspicion of tuberculosis was negative, or in which the human tyi)e was found exclusively, and 4. Cases in which no affections whatsoever have been dem- onsti-ated up to the present time. In Group 1 an infection with the bovine type was demonstrated in two families, alVectinii- one child in each. 110 Tuberculosis. In both cases it Avas possible to trace the consumption of milk containing the bacilli up to the nursing age. In one case it lasted for one and a half years, in the second case one year, and in the latter case the udder affection had been recognized for three months during the period that the child had been using the milk. In both cases the respective cow was affected with a severe tuberculosis of the udder in all four quarters ; the milk had been consumed at all times mixed with the milk of a second cow, in the first case boiled or raw but in the second case only raw. The other members of the family remained well in spite of the consumption of this milk ; in both instances only the youngest child became affected with tuberculosis of the cervical glands. In the first case another child of four, and one of five years, was included in the family ; in the second case children of the age of 3, 4, 7, 8, 9 and 12 participated in the consumption of the milk, all remaining normal. The tuberculosis of the cervical glands healed in the two 3^oungest after abscess formations, leaving several slightly en- larged small glands in the surrounding parts. One of the boys appears to be in the best of health, the other is somewhat behind in his development (at the age of 2 % years he weighs 251b s.) ; in the last six weeks however his weight increased slightly more than 1 lb. In the cases of the second group there exists suspicion of a bovine type of infection. In six children and one adult there are swellings of the cervi- cal lymph glands and in four children and one adult a suspicion of aixlominal tuberculosis is given. One child is affected with scrofula. In the four children the manifestations of disease re- trogressed, while in the adult it appears doubtful, according to Weber, whether the affection is of a tuberculous nature. Forty-one persons are included in Group 3, who consumed milk in a raw state from cows affected with tuberculosis of the udder. This was at times mixed with milk of other cows. A girl of 16 years of age and a boy four years old, who died of tuberculosis were included in this group. The producers of their infections were bacilli of the human type. A man and a woman who were affected with pulmonary tuberculosis (human type), a boy with suppuration of the middle ear and cervical lymph glands (not tubercular) ; an 18-year old boy with rheumatism of the joints and valvular heart trouble, chronic diarrhea and pulmonary symp- toms (not tubercular) ; a woman with catarrh of the apex of the lungs (not tubercular) ; a woman with swelling of the glands, diarrhea, cough, night sweats and emaciation (inoculation of sputum without results), and a woman and a man with pulmonary s}^nptoms (not tubercular) were also in the total of forty-one. The cases in which a boy and a girl died from tuberculosis, are of especial importance. In spite of'the prolonged consump- TaljU: III. s H «* a0% • % ..•%^ ^^^ ^- m ( t: ^ Milk from a tuberculous adder. 1 X 1200. /■,',„s/. Milk UiKji'-nf. Danger from Buvine Tuberculosis. 211 tion of raw milk from a tuberculous udder by the children Avho were already infected with the human tvpe of the disease, it was impossible to isohite from the tuberculous glands of the neck and mesentery any bacilli of the bovine type. AVeber concludes from this that a l)ody already infected with the human type of the dis- ease IS resistant rather than susceptible towards an" infection with the bovine type. Tlie fourth group contains by far the greatest number of cases in which children and adults consumed raw milk from cows affected with tuljerculosis of the udder, or milk products prepared from the same, and includes those cases in which no disturbances of the health resulted from such consumption. It was especiallv stated relative to the children that they all appeareil thriving and healthy. Among these persons are included those who for a" long- period ingested especially great quantities of bovine tubercle l)a- cilli; thus a Di-month old child has been brought up exclusively on raw and boiled milk from a cow affected with udder tuberculosis, and up to the present remains healthy. Other cases may be considered as presenting complete ex- periments with the necessary controls, since the persons who drank the milk remained healthy, wliereas calves and hogs fed with the same milk developed severe ingestion tuberculnsis. The ob- servations of such cases may be traeed back incompletely for 3 or 4 years. A 25-year okl waitress, and a 28-year old dairy hand drank nuiRfnls of freshly drawn tuheruidous milk, freqiieiitlv without any other milk being ailded without be- coming affected; the calf of the cow which produced the milk had to lie slaughtered after four weeks, and slioweil tuberculosis of the mesenteric lymph glands, liver, lungs and kidneys, a severe ingestion tuberculosis. The milk of another highly affected tuberculous cow also suffering from ndder tuberculosis, was mixed with the milk of two other cows, and was consumeil frequeutlv in a raw condition, by two adults and a l.S-year child; a child l^i years of aire was given the milk only in a boiled condition. The adults remained healthy; the calf from tliis cow had to be slaughtered after five weeks, and showed generalized tuliereulosis. Prom the stable of a herdsman the milk of a cow aifected with udder tuberculosis was mixed with the milk of three other cows, and the cream and butter prepared from this was consumed by fonr persons, aged 31 to 59 years, without producing any ill effects. The five hogs of the herdsman were found on postmortem to be tViberculous. Similar results were reported from the ingestion of milk from a tuberculous udder of a goat, which was consumed as raw and boiled milk by three adults and four chil- dren of ages from 5 to 16 years. The persons remained well while a hog became af- fected with ingestion tuberculosis. In two other cases the milk was consumed in a raw or unmixed state, as milk, buttermilk and butter. It was consumed by seven adults, in one case for a period of four months, in another case even longer. In spite of the fact that the family has been kept under observation for four years no ilisturbance in health can be detected. It is proven by the collected material of TVeber that even though tremendous quantities of tuberculous material are con- sumed, still more favoring accessory conditions are necessary in ordei- to produce an infection with the bovine type of tubercle l)acilli. Of course it is not yet known, as indicated by Weber, how many of the children which show swelling of the cervical IjTnph glands and s^nnptoms of suspected abdominal tuberculosis, are 112 Tuberculosis. affected with the bovine type of tuberculosis, or how many of the persons who fail to show any disturbance of health may harbor one or more infected mesenteric glands ; likewise it is not known how many children with a latent form of the disease may through a special weakening, or under the influence of other infections, break down later with tuberculosis, possibly even with a fatal termination. Through the compilation investigations we know only of the time (which extends over a period of 1-3-4 years in the individual cases), the opportunity and the immediate results of the infection, and not the further development of the same, but we do know that in two children a true bovine type of tuberculosis existed. Therefore, although a possibility of infection was present in a great number of persons, the infection has positively occurred up to the present only in two children in infancy. This constitutes proof that "the danger which threatens man from the consumption of milk and milk products from cows affected Avith udder tubercu- losis is very slight when compared with the danger of man affected with open pulmonary tuberculosis to his fellow men." This conclusion of Weber may be supported without further consideration. Nevertheless the danger still prevails, and al- though it is slight in comparison with the danger through infec- tion with the human type, it should be by no means under-esti- mated; it should be considered that the danger of infection with human tuberculosis is amazingly great, and the opportunity of ingesting the bovine type of tubercle bacillus with milk is similarly great. Bovine Tuberculosis in Man in General. Although the attention of pathologists of all countries has been directed for the last ten years to infections of man with bovine tuberculosis, up to the present time there are collected only 117 cer- tain cases of bovine tuberculosis in children and 21 cases in adults (over 16 years of age). _ Of the 117 eases in grown children 105 are accurately de- scribed, and involve the following organs : 60 cases of abdominal tuberculosis 25 cases of tuberculosis of the cervical glands 4 cases of tuberculosis of the tonsils 7 cases were generalized 3 cases were localized in the bones and joints 6 cases represented lupus Two cases should also be included in which bovine bacilli were found in unchanged lymph glands. The 60 cases of abdominal tuberculosis are again divided into 34 severe cases in which the mesenteric lymph glands, the intes- tines and the peritoneum showed changes". Thirty of these after generalization of the affection, terminated in death. Bovine Tulicriuldsis in Man. II'P, Twelve of the 60 patients had tuberculosis of the mesenteric ^dands, slight intestinal tuberculosis, and tuberculous meningitis. The 12 cases were severe fatal affections. In 14 cases the autopsy revealed tuberculosis of the mesen- teric lymph glands with the bovine type of bacilli, but this was found accidentally following other causes of death, as diphtheria, scarlet fever, measles, and pneumonia. In the 21 adults the bovine type of the disease was established three times in pulmonary tul)erculosis Avith expectorations, onco in a primary abdominal tuberculosis and pulmonary tuberculosis, once in an infection of the buccal mucous membrane and cervical lymph glands, once each in tuberculosis of the knee joints, the kid- neys and the peritoneum, and finally the bacillus of bovine tyi^c was isolated from three cases of lupus, two cases of skin tuber- culosis, and five cases of tnhcmilos'is rernirnsd cutis in butchers. Besides these instances the bovine type of tubercle bacillus was isolated three times froin the mesenteric glands of adults. In two cases of phthisis tlie bovine tuhei'cle bacillus was found in association with the human type. Of the total of l.'!S cases, .'>(> were fatal, and SO could be ex- plained with certainty or with the greatest prol)aliility as inges- tion tulierculosis. The other forms of tubcrcuhisis, with the ex- ception of tlie skin tuberculosis of the butclicrs and of one milker, may also probably be ti'aced to the saiiie mode of infection. Welier deduces from his lindings tliat tiic daimcr of bccoinini;' infected with tubercle bacilli of cattle is great for the individual, but is only sliglit for the human race as a whole Kossel reports in the German jMedical Weekly relative to tlie number of cases of animal tuberculosis in uuin as compared with the hunmn type of tuberculosis, and observed that in KilVJ cnses of human tuberculosis the bovine type appeared as the infective agent in ^2(^ cases, the human type alone in 14fi4 cases, the human and bovine type in association nine times, and the avian type of tubercle bacillus three times. Therefore in about S.(i<^^ of human tuberculosis, bacilli of animal origin were found, and in about S'^r of these they were of the bovine character. If however the most freijuent form of tuberculosis of man is considered, namely pul- monary tuberculosis, then the bovine typ^ can be demonstrated only in about .fi% of the cases, whereas in the other forms of tuberculosis it nmy be found in 16 ^r of the cases. Tuberculosis of bovine origin occurs most frequently in chil- dren in which tuberculosis of the cervical glands is caused in about 4:0'"i of the cases from infectious with the bovine type, and tuber- culosis of the mensenteric glands may be traced to the same type in 40 to .lO^r of the cases. A portion of these affections, as has al- ready been nu^ntioned, may terminate fatally. Among the fatal forms of tuberculosis in childi-en 76'7'c are caused by the human tyi)e and 24'/'c by the bovine form. The meningitis type of the 8 114 Tuberculosis. disease is brought on in only about 11% of the cases by the bacil- lus of animal origin and in 89% by the human type of the organism. In tuberculosis of the bones and joints the figures are 5% and 95% respectively. Gaffky, Rothe and Ungermann found in 400 bodies of children, 76 infections with tuberculosis, in which they succeeded in estab- lishing the variety of the bacillus. In one case they found the bovine type (1.32%), and among 171 other autopsies on children, of which 39 were tuberculous, two (5.1%) cases of bovine infection were observed. The results of tuberculous infections among children of the population of Berlin were therefore 95 to 96% of human origin, while only 4 to 5 % were of bovine origin, in spite of the fact that during infancy the danger of bovine infection is the greatest (Kossel). [According to figures compiled by Park of the New York City Board of Health, the frequency of bovine tuberculosis in man as collected by various investigators is as follows : In adults, 955 cases have been examined of which 940 showed human infection and 15 bovine infection. In children from five to sixteen years of age, out of 177 cases investigated, 131 were human infections and 46 bovine infections. Among children under five years old there were 368 cases of which 292 were found in- fected with the human type and 76 with the bovine type of tuber- culosis. Furthermore Park mentions the very suggestive results obtained from nine children under 6 years of age who were fed exclusively on cow's milk at the Foundlings' Hospital. Five of these children died of bovine infection and four of human infec- tion. On the other hand in the Babies' Hospital where the infants are nursed or fed on prescription milk, out of 63 children dying of tuberculosis, 59 proved to be human infection and 4 bovine infection. The figures taken from clinical work in England indicate that from 23 to 25% of the fatal cases of tuberculosis in children are due to bovine infections. Stiles of Edinburgh has presented in- teresting statistics to illustrate how bovine tuberculosis particular- ly affects young children. Of 67 consecutive tuberculous bone and joint cases, the bovine bacillus was present in 41, the human bacil- lus in 23, while in 3 cases both types were present. In those af- fected children under 12 months old, only the bovine bacillus was found. Of the 12 children between 1 and 2 years of age, 8 owed their disease to bovine infection, 2 to human infection and 2 to both bovine and human infection. There were 15 cases in 2 to 3 year old children, 11 of which were bovine, 3 human and 1 both infections. The 1 cases from the 3 to 4 year period were 6 bovine and 4 human infections, while the 4 to 5 year period included 3 cases of each type of infection. Stiles further reports on 72 cases of tuberculous cervical glands operated on at the Children's Hospi- Control of B'lvine Tuberculi isi;^. 115 tal in Edinlnn\!;li, in which the disease was due to the bovine bacil- lus in 65 cases, while in only 7 patients was the disease caused by the human bacillus. — Trans.] Conclusions. If we compile the results of this chapter the following conclu- sions may lie estaltlished: Although tuberculosis of cattle is less dangerous for man than tuberculosis of man, the danger from the enormous spread of tln^ disease in our herds, and especially among the dairy cows, should in no way be under-estimated. Theoretically the possiliility of infection is afforded in all cases in Avhich the ingestion of living tubercle bacilli with the milk takes place; from a jiractical stand- point however this possibility of infection comes into consideration only when the ))acilli enter the individual in great quantities, and the resistance (of a local or genei-al nature) of the ))ody is not e(|ual to this quantitative attack. This disposition, or these rela- tive conditions between the injurious a.ueiits and I'esistanee, appear to be especially unfavorable in children ; therefore the requirement of the eUmination from dairy herds of all tuberculous annuals which i)ass tuhercle Ijacilli with their milk, aiipeais to follow as a matter of course. According to tiie experience at the tul)ercuhisis eradication stations only those animals nnist be considered as eliminators of tnliercle hacilli which are arfecte(l with open tuber- cTilosis, and ex))el the tuhercle bacilli with their secretions and excretions, esiiecially animals alTectetl with tuberculosis of the udder, open pulmonary tuberculosis, tubercnlosis of the utern-, intestinal tuberculosis, and furthermore aninuils with tuberculosis of the liver, kidneys, skin, eyes, and larynx. Measures Against the Danger. The elimination of animals passing tubercle Imcilli sbonld also be energetically encouraged on general economic grounds. For this work three methods may lie followed: 1. Treatment of the disease and curative attempts. 1'. The inununization of healthy herds. .'b Energetic sanitary police eradication measures, reduction of the possibilities of infection, and lU'otection of young animals fi-om infection, together with favorable conditions for bringing u]i young stock as a preventive nu>asure against their accidental infection, toward which we are iiowerless. The curative measures in affected animals may he left out of consideration as measures of control, since— excepting the uni- formly bad or only slightly favorable results — the methods of treatnient for veterinary practice are too complicated, and are not )n-acticable in c(msideration of the value of the animal. For the sake of conii)leteness the experiments with iodipin should be mentioned here (llauptmann). Creosote has also been employed. 216 Tuberculosis. Of the specific remedies, tuberculin, tulase, tulase-lactin, tulon and tuberculase could be considered in the treatment of affected animals. These bacterial preparations, however, accord- ing to Eomer and Arloing, are ineffective, since the results were negative. Better results were promised at the onset, from the specific immunization methods, which aimed at a systematic preliminary treatment with slightly virulent strains, or with attenuated bovine tubercle bacilli, to increase artificially the resistance of the im- munized animals, that is, to protect them against a later accidental natural infection. As a matter of fact cattle immunized with tubercle bacilli prove for a time to be immune, or at least manifest a considerable resistance against a subsequent artificial infection with bovine tubercle bacilli, when compared with non-immunized control animals. For immunization purposes there have been used : 1. Dry tubercle bacilli of the human type (bovo-vaccine. Von Behring's method). The injection is made into the blood circula- tion and is repeated. Animals treated in this way after 3 to 4 months, resist an intravenous injection of bovine tubercle bacilli, to which untreated animals invariably succumb. This increased resistance however lasts only a short time. According to the in- vestigations of Eossignol and Vallee and Hutyra it diminishes to- wards the end of a year, and after another six months it practically disappears. Against the slight practical success of this method the disagreeable fact should be considered that the injected tubercle l)aeilli of man are retained alive in the body of the cattle for years, and may even produce in the udder local tuberculous processes, frpm which the bacteria of human tuberculosis may enter into the milk (Lignieres, Weber and Titze). Titze found that following an intravenous injection of liiiman tubercle bacilli, they were eliminated from the udder even 16 months after the injection. In this regard the various individuals manifest an entirely different behavior. In three other cases bacteria were eliminated after a single injection, from the fourth week up to the 144th day. In a second cow which received an injection of tubercle bacilli of human and bovine type the elimination commenced after the third injection, and in a third cow as early as 24 hours after the injection. All three animals eliminated the bacilli from only one quarter, vpithout this showing tuberculous changes. Bongert found in 186 bovo-vaccinated cattle, 36 which passed tubercle bacilli with their milk. The protective vaccination of Yoti Behring therefore is not only of Kttle practical value, but grave dangers must be considered in connection with it, since the vaccinated animal may eliminate tubercle bacilli with the milk for 21/0 years and longer. Koch and Schiitz, Neufeld and Miessner recommended for the immunization of cattle a single injection of 0.01 gm. tubercle bacilli m suspension, which vaccine they termed ' ' tauruman. ' ' The above statement applies equally for tauruman as it does for bovo-vaccine. Similar results to the immunizing value of the in- travenous injections, according to Baumgarten, Lignieres and Tul)erpnliisis Vaccination. HJ Klimmer may lie (U'rived from the single subcutaneous admin- istration of liunian tubercle bacilli. According to Lignieres even in such cases the bacteria may remain alive for as long as two years. According to Von Behring, Calmette and Guerin, Boux and Vallee, cattle may liecome iinniiinized liv feeding with slight quantities of bacilli from tuberculosis of the horse (or bovine tiili(>ri-iilosi'^). Arloing attempted to immunize with homogenized cultures of strains which had 1 ri'ii cultivated in 6% glycerine bouillon (human type and bovine tj-pe). Better results were obtaineii from the intravenous than from the subcutaneous applications and this again proved superior to administration per os. Klimmer eliminated the danger of the vaccination for man by heating the human tubercle bacilli to 52-53 deg. C, or l)y rendering them a*viruleiit by continuous passages through the crested newt. Both these vaccines are no longer pathogenic for giiinea pigs, and they cannot regain their virulence by means of passages through animals. Tlie results of immunizations arc sujijxised to be favora- l)le (Klimmer on 10,000 cattle), especially if the vaccination is carried out together with g<'neral ])i-etective measures, such as raising calves on milk free of tulierculosis, and the elimination of animals with open tuberculosis. (Jlockner even believes that vac- cination has a favorable action on the curing of animals which wcic already al't'ected with li()\'ine tuberculosis ])rior to the vacciiuition, whereas Eber attributes tlie improvement of the vaccinated herds to the simultaneously executeil j)i'opliylactic and liyuienic meas- ures. Friedmaun aimed to produce immunization with his tuher- cle bacillus from cold bUxxh'd animals (turtle)- Other authors however failed in ])rodneing an effective inimuuizatioii with such strains (Tjibhertz and Ruyipel, A\'eber and Titzc, Oi-th). Ileymanns attem])ted to immunize cattle by the introduction und<>r the skin of cattl(> of a closed sack of vi'^etable fiber, contain- ing living tubei-cle bacilli (hmnan or bovine in origin). The su])- l)osition is that these veg(>table sacks -will confine the bacilli at the seat of inoculation, and that the treated animal will be immunizec] by protective metabcdic products, that continuously fonn in small (|uantities within the sack and ]iass outward from it into the animal's system generally, by an osmotic process. The vaccination, which is carried out with the aid of a tro- car to insert the capsule under the skin of the back, must be re- peated annually, since the bacilli may die. HeAinann's method has been successfully used by its discov- en'r on more than 'J0,000 cattle, and the percentage of reactors to the tuberculin test diminished from 4.") to 21 (IS herds with ISS animals). Animals Avhicli have formerly reacted may appear free at the subsecinent test. Good results were obtained by Vallee from passive immuniza- tion. He inoculated young cattle with 100 to 200 c. c. of a protec- tive serum, wliicli he obtained from a horse treated with slightly virulent strains from horses, and then with strains from men. \1^ Tuberculosis. With this method he siieceeded in rendering the animals resistant to artificial infection with bovine tubercle bacilli. Since immunization methods have not offered uniformly satisfactory results, and since they must be prohibited on the ground of milk hygiene, therefore results may be expected only from proved sanitary police measures. The methods which must be followed in the eradication of bovine tuberculosis are : 1. Diminution or elimination of the sources of infection, (a) By removal of the animals passing bacilli, (b) By separation of healthy and suspected or diseased animals, (c) By bringing up tuberculosis-free young animals. 2. Improvement of the general methods in the care of young stock, hj introducing conditions which approach the natural mode of living: (a) Proper care and feeding in well ventilated and lighted stables, (b) Dividing the pastures so that the animals may be sepa- rated (according to whether they are suspected or healthy) and kept in accordance with their age and with the use for which they are later intended. Measures for eradication must be applied in accordance with the rules here outlined. The most effective method of eradication was worked out by Bang, and consists in the elimination of clinically recognizable dis- eased animals, the separation of reacting animals, and the bringing up of calves on milk free of tubercle bacilli. The remarkable value of Bang's methods has been proven fully in practice l)y the results obtained since 1892. It is important for the results to separate completely the animals which fail to react to tuberculin, that is the healthy cattle, from those which harbor the disease and which react to the tuber- culin test. This should be done in such a way that the healthy animals are placed in a freshly disinfected stable or in a portion of a stable provided with a separate entrance, and separated with a board wall, from that part in which the reacting cattle are housed. The attendants of the healthy herd should not come in contact with those of the diseased herd. Animals of the reacting group which after a time become affected so that they may be clinically recog- nized, should be slaughtered as soon as possible. Young stock which react should not be permitted to breed, or at least should be immediately placed with the reacting group, providing their breeding value is such that this procedure is deemed advisalile. All reacting animals under six months of age should be slaughtered, that is they should be utilized for meat. Ydung stock and work oxen should also lie included in the Methods of Eradication. 119 soo-iooation, and tlie liealthy ones must be kept from contact with i('actin,n' animals. Of tlie calves which are horn after the separation, those from non-reacting- cows remain with their mothers ; the calves from reacting cows, after receiving the colostrum from their mother on the lirst day after birth, should be placed in the stable of healthy animals, and should be fed with the milk of healthy cows or should lie brought up on sterilized milk, or they may be allowed to suck from healthy nurse cows. As soon as possible after weaning the calves should also lie subjected to the tuberculin test, and those giv- ing a reaction should be immediately removed. From 1 to -""c of these calves react. It is proper to place the healthy calves in a stable of healthy young stuck, and they may pasture with them, or if this is not pos- sible they should be ))laced with the older uon-rcacting ginu]) of animals. Before the first breeding the heifers again should be subjected to the tuberculin test, in oi'der to jilace them in the prop- er grou]) of cows. The tuberculin test is annually rejieateil in the healthy herd, in order to eliminate the animals which in the course of the year have had a ])ossible opportunity of becoming affecteil with luliercnlosis. Newly i)ui'cliased animals ar<' clinically examined and b'-led with tuberculin, and ar(> added to the healthy herd only when the results are entirely satisfactory. The male animals which are to be used for breeding imrjio^es should not react to the tuberculin test. Under nmivoidable cir- cumstances, a reacting bull may be reserved for bleeding pur- poses ))ut only under special ])recautionary measures. The I'esnits of Bang's eradication method, if carefully carried out, are remarka))ly satisfactory. It has been adojited to the greatest extent in Denmark, Swe(leu and Norway, and it has also been successfully carried out in Hun- gary and Finland. The report of Regner, in 1911, affords a good review of the results of Bang's method, and in it are described the results of thi- go\-ernmental eradication of tuberculosis in Sweden. Eegner di- vides the eradication work into an offensive one in herds in which the diseas(> prevails, and into a defensive procedure wliose purpose is tlie prevention of the introduction of diseased animals into herds free of tuberculosis. ( )f the groups into which Regner separates the herds and the animals, the lirst group includes those Avhich originally (on the tirst tuberculin test which in some instances was applied years previouslv) were found tuberculous. At that time 16,852 animals liad 1 n tested with a percentage of oO . 2 reactors. In 1908, is, 719 animals in \'u Iierds jiroved to be entirely free from tuberculosis. The Iierds of the second group, which proved to be tuberculous 120 Tuberculosis. at the time of the inauguration of the method and which continued to contain reacting animals, included 375 herds of 21,899 animals, with 41.5% of reactors. At the end of 1908 the number of cattle had increased to 26,181, of which only 1,496, or 5.7% reacted. The results were not so pronounced when the reacting animals were retained with the healthy animals, when cattle without the necessary precautionary measures were placed in herds free of tuberculosis, when animals which had not reacted in the old herd were removed into the free herd without being previously tested, or when an opportunity was given for the transmission of the in- fection by a reacting bull causing the infection in the herd to ap- pear to be renewed. Also in cases when the milk used for the feed- ing of calves was not free from tubercle bacilli, the results were unsatisfactory. In the interest of systematic eradication, it is necessary, espe- cially at the commencement of the eradication work, to subject the animals to the tuberculin test quite frequently, with short intervals. As a third group Regner included 436 herds containing 7,835 animals at the beginning of the work and 9,114 cattle in 1908, which at the first examination, and again in 1908 were free from reacting animals. The fourth group contains the herds which originally were free from tuberculosis but were not so at the test in 1908. The 98 herds included at first 2,526 and in 1908, 3,720 animals, of which 265 or 7.1% reacted. Regner concludes from his tabulations : that on the first tuber- culin test in 1366 herds, out of 49,112 animals tested, 14,175 or 28.9% reacted; that in 1909 the same herds contained 57,734 ani- mals, of which 1761, or 3.1% reacted; that Bang's method is the strongest factor in the general promotion of breeding, and of stable and milk hygiene. In other countries the results were similarly favorable. Bang succeeded in Denmark, from 1893 to 1908, in gradually reducmg the percentage of reacting animals from 40 to 8 . 5. Malm m Norway from 1896 to 1903 reduced the disease from 8.4 to 4.9%. Hojer in Finland in 1894 to 1900 caused the infection to drop from 24 to 10.1%. Hutyra reports on experiments carried out on the government farm of Mezohegyes. In this herd the first tuberculin test in 1898 showed 44.8%, of reactors out of 329 cows or 26.6% of the entire herd (647 animals), whereas in the fall of 1903 out of 502 cows only 2.8%, and out of the total of 1,132 animals only 1.8% reacted to the tuberculin test. The herd had been increased in this period by 75%, without purchasing additions to it, and the percentage of reactions had dropped 88%. The stringent measures of Bang have been somewhat modi- fied m certain cases for economic reasons, or when the strict execu- tion of Bang's method has presented peculiar difficulties. On the Ostertag's Method. 121 other hand the rcMiuirements have been accentuated in cases where favorable considerations prevailed. Thus for instance in a herd in which only a few animals react it would be advisable to dispose of them without further consideration, and after a thorough disinfec- tion of the stable the defensive work against tuberculosis may be instituted, thnnigh the introduction of only non-reacting cattle, and by the dis])osing of all animals which prove tuberculous on the following tuberculin tests. The Siedamgrotzky-Ostertag method consists of immediate disposition of all animals with open tuberculosis (by this means the animals eliminating tubercle bacilli are excluded), and in bringing up the calves free of tuberculosis by feeding them with ))asteurized milk or with milk from healthy cows. The calves ar(^ subjected to the tuberculin test after they are weaned, and the re- acting animals are not bred. The herds which are included in this method of ei'adication are sub,j<'('teil semi-annually to a clinical examination, and the clinically susix'cted animals are removed and disposed of. Further than this, the mixed milk of the herd, as well as the suspicious secretions and excretions are examined bacteriologically. The results of the Ostertag eradication method of course can not be compared vrith that of Rang. Since there are retained in tlie herd all tuberculous animals whi<'li show no clinical form of tuberculosis, or in which there is a suspicion of ojien tuberculosis but whose secretions and excretions fail to I'cveal llie |)reseiice of tubercle bacilli. Therefore a constant danger of infection for the animals free of the disease prevails, as tulierculosis nmy at anv time develop into an open form. But since it is r(M|uiied that the calves should be brought up free of tuberculosis, and that the elim- inators of tubei'cle bacilli should be determined by ]ieriodical clin- ical examinations as well as by the testing of the entire mixed milk of the herd and the individual secretions and excretions of sus- pected animals, Ostertag has obtained relatively very good results, where his requirements have been conscientiously carried out. This method has an advantage in that the stock owners who offer great objections to radical methods of eradication on ac- count of the immediate economic losses which they entail, are will- ing to work intelligently and with pleasure with a system of era^iiitr popularity of this method. The method was roluntarily adopted in the fol- llii'lMiMit, 1.4r,7 animals: IfliU "190.T, l.P.Til; 190o-190n. .1,.13:?; 19rifi-1907, -..195; 19117 19IIS, .-,19-i: 19iiS-l'.Mi!i, s,s:;;i; 1009-191(1, ls.si2; and 1910-1911. I'.i.Sis animals. The followins: '':>t« illustrate the results obtained with the method: Open tuliiTculosis was present in the province of: East Prussia in 1900 in 2.7 % out of 10900 examinations l-':-i i" 3.46^^ out of o-OO examinations 122 Tuberculosis. Brarifleiibnrg in 1907 in 1.5 % out of .5810 examinations Sclileswig-Holstein in 1903 in 2.8 % out of 2435 examinations Schleswig-Holstein in 1905-6 in 1.93% out of 11000 examinations Saxony in 1903 in 3.6 % out of 1457 examinations Saxony in 1906-7 in 2.41% out of 5395 examinations In tliese statistics it sliould be considered that every year new, unexamined herds have been included, and further that the experts continually gained more skill in making the examination. A proof of the reduction of the dangerous forms of tuber- culosis is first of all indicated ))y the above figxires, and also by the marked reduction of tuberculosis of hogs. Thus for instance ac- cording to Stier the percentage of tuberculous creamery hogs which amounted to 40% was reduced to 4% after the elimination of six cattle with tuberculosis of the udder, although none of the skimmed milk fed to the hogs had been sterilized. In 1907 out of 38,454 animals examined in Schleswig", 1.4% were found to be affected with pulmonary and udder tuberculosis. Udder tuberculosis alone was clemonstrated in 0.124%. In spite of the great advantages of the method, the results eventually come to a standstill, as may be seen from the more recent reports of the eradication stations. The number of the dangerous forms cannot be reduced below a certain percentage, since latent forms contin- uously change into the dangerous forms, and it is therefore im- possible to eliminate the sources of infection from the herds. The method of Ujheiyi also deserves mention. In this method the cattle are divided into a healthy herd and those which react to tuberculin. The newly born animals of the group giving a positive tuberculin reaction are allowed to remain only in emergency cases with the reacting mothers, but if possible they are nursed by healthy cows. After weaning the calves are tested with tul'crculin. This method differs from Bang's method only in that sterilized milk is not used (prevention of calf diarrhea) and further the calves are allowed at times to remain with the reacting cows. According to Iljhelyi's report this method has given irreproachable results. It has to be considered however that of the weaned calves a greater proportion of animals must be eliminated when this method is employed, than when Bang's method is followed. Before the introiluction of Ujheiyi 's method, out of 1,031 adult cattle, SS4, or 85.7% reacted. Out of 626 young stock 333, or 53.2% reacted. After a period of eradication for 4% years Ujheiyi succeeded in reducing the infection to 4.1% among the adults, and 2.6% in the young stock. He succeeded in the periods from 1898 to 1902, and from 1904 to 1905, in reducing the number of positive reactions among 1,715 cattle, of eight state farms, from 59% to 3%. The eradication of tuberculosis has been subjected to official control for several years in Denmark, Sweden, Norway and Fin- land. Thus Denmark in 1893 contributed $13,500.00, "later $27,- 000.00 towards the eradication of tuberculosis, furnished the tuber- culin free of charge at first for young animals, later for adults, and finally since 1898 took upon itself the total expenses of eradication (Hutyra). The skimmed milk is permitted to be returned from the creameries to the stock owners only after being heated to 80 deg. C. Cows affected with tuberculosis of the udder are destroyed, the owuers being reimbursed. There are about 600 such animals paid for annually. Similar results were obtained in Sweden, which adopted legis- lative measures and made a contribution of $225,000.00. In the IC^■^lllt> c,f Control V.'ork. yoars from 1S!)7 to 1908 in 1,370 herds with 48,576 animals, of which 14,l'l25 or 29.;]% reacted, the amount of infection was re- duced ))y their work of eradication to such an extent that out of 57,660 cattle only 3.1%, that is 1,765 animals, reacted. Although the statistics of individual countries having strict measures of eradication (Denmark, Sweden, etc.) appear to show the splendid effects of carefully executed control work, based on scientific principles, and in spite of the fact that the milder modifi- cations, as for instance that of Ostertag, Ijy no means show the same good results, nevertheless measures of too strict requirements cannot be absolutely approved. Thus for instance Belgium in 1895 requirer] the destruction within a certain time of all clinically affccte'l and all reacting animals, and in IMiii out of 19, 1104 cattle examined !),2si) were slaughtered. The difficulty of the execution was lesseneil by the law of 1S1I7 wliich required that only the visiliiy affected animals shoulil be ilc^troyed, a measure which rcsultcil in the destruction of 10,269 cattle with reimbursement amounting to $:;00,000.00, in 1902 (Hutyra and JIarek). Theoretically, the most radical eradication measures may pos- sibly lie considered as the (|uickest and niDst effective, and tlierefure from an economic standpoint as the best methods for the control of tuberculosis, (')wing to the exf I'aordinary s])read of this dis- ease in almost all herds, drastic nieasni'es however may result in (lie sudden infliction of such heavy economic losses, not alone tlirongh the animals destroyed, but throui^h changes of values for breeding, dairy purposes, meat production, etc, that the stock owners, dealers, consumers, etc., Avould have good grounds to ])ro- test against the execution of such methods. Therefore it is advisal)Ieto ado]it ( )sterta,n's nu'tliod at tlie ini- tiation of Ihe general work of eradication, and aft<'r the stock own- ers have been convinced tliat the idea is rational followim;- the favora))le practical results obtained, then Bang's metlio(l may be introduced, unless it is iiossible to persuade* them to employ, at the beginning, the rational execution of Bang's method. In no instance however should destruction of the reacting animals be re(|uii'eil in connection with Bang's method. From the standpoint of milk hygiene it does not seem to be justifiable, according to the ])resent status of the question of the infectiousness of the milk of reacting animals, to re(|uire their exclusion from the production of milk, unless they show clinical evidence of the disease. In s])ife of the separation of the reacting from the non-react- ing animals, the milk of the reacting group could be marketed, from the stand])oint of milk hygiene, with the milk of the other gi-ou]!, without interference, as has been previously practiced, so long as there is no substantial proof offered as to the danger of marketing such milk. With the new law on diseases of animals the initiation of eradication, based on uniform legislative measures, has been in- s1itnte(l in (lermany, and thereby serves as a stimulus to extensive privati' activity in matters of eradication. 124 Tuberculosis. The law requires that clinically affected tuberculous animals, or those in which tuberculosis probably exists to a great extent, may be ordered destroyed by the police authorities. If this is not carried out, or if the destruction is postponed, sanitary police protective measures should be inaugurated against further spread of the disease, by branding the animals. The police measures against the spread of the disease con- sist in separation, observation of police control of the affected, sus- pected and susceptible animals ; if necessary restriction of traffic of both man and animals, and special limitations relative to the use of affected or suspected animals, and their carcasses, and finally the usual requirements of disinfection. For animals which are destroyed by the requirements of the police, and those which after destruction has been ordered, die of the disease on account of which they had been ordered destroyed, the government allows corresponding- reimbursement. Of great importance in tuberculosis eradication is the require- ment prohibiting the return of skimmed milk and other milk residue to the milk producers, as food for other animals, unless the same has been heated. This clause is included in the general requirements of the measure. Centrifugal slime, which has formerly caused the development of ingestion tuberculosis in hogs, must be destroyed by burning or burning. The measures differentiate three danger classes in tuberculo- sis: (1) the simple suspicion, (2) the great probability of its presence, and (3) the actual existence of the disease. In the pres- ence_ of the clinically recognizable classes of tuberculosis, it is required that the milk from such affected animals should not be sold or otherwise utilized without being previously subjected to a required temperature for a certain length of time. The milk from cows affected with tuberculosis of the udder cannot be used for human consumption even after subjecting it to the required heat, nor can it be utilized for the preparation of dairy products. The requirements in Bavaria order the destruction of an ani- malonly when it belongs to a herd in which cattle breeding, or raising of cattle is industrially followed, and an appropriate volun- tary method of eradication of cattle tuberculosis may then be carried out in the herd under veterinary supervision. This ought to result in a considerable improvement of the tu- berculosis question, and with the elimination of animals which prin- cipally enter into consideration as distributors of bacilli, a point is gained which temporarily should thoroughly satisfy even the milk hygienists. With such measures the stock owner is pleased, as the pro- fessional direction of rational breeding in connection with eradica- tion is shown to be for his advantage. This constitutes the basis I'acilhis Pyogenes. X25 on wliicli the entire milk production in all its relations may be ele- \'ated, and will be elevated, since the voluntary intelligent co-opera- tion of the owners constitutes the fundamental principle on which the state bases its allowance of reimbursement. Without the voluntary co-operation of the producers, the elevation of milk hygiene is practically impossible. It will take years before the conditions will markedly improve, but the improvements will surely come, and they will not confine themselves alone to the tuberculosis question. Other Forms of Mastitis. The other forms of chronic mastitis, with the exception uf tuberculosis of the udder, are of slig'ht importance for jiractical purposes when compared with streptococcic mastitis. Thus for instance the mastitis ])r(jduced by the BuciUns pi/nf/- cncs bovis is relatively rare, and the author has had the ojipor- tunity on only three occasions to attribute the development of chi-oiiic mastitis to the Bacillus pijoi/ciics. (Jlage, Nielsen, Kuhl- mann, and Sven Wall, however, have observed tlie infection fre- (pieiitly, and even desci-jbe an epizootic extension uf the infection. ]\lixed infections of staphylococci and c()h)ii bacteria, witli the JJacillns ])!/(>fj('iies, appear to be nioi'e fre(|neiit and in these cases a severe mastitis is i)r()dnced. It results in abscess formation and neci'osis of the aU'ected parts, with an induration of tlie tissues. The secretion is sanio-pnrulent, and mostly of an offensive odor. Kiimiemann found the bacillus at lirst in suiiiuirations of catth-, and (Jrips in suppurating processes of lio^s. They are small, deli- cate rods of the size of th(> swine erysijielas bacillus, iii'owim;- bet- ter anaerobically than aerobically, forming dew-drop like colonies on agar, or serum ai;ar. Llilk coagidates to a uniform clot. The bacillus does not take the Gram stain, but it may be stained by \\'eii;('rt's method. Very little is known relative to the behavior of the BuciUiis plldjioics hovis towards man. According to the author's observa- tions it appears to belong to the group of pseudo-intiuenza bacilli (Pfeiffer). Such rods were found in influenza-like pneumonias, in bronchitis (Pfeiffer), in suppuration of the middle ear (Ivossel, Ilartmann, Pielicke and Cantani), also in whooping cough (Afan- asieff, Szewetschenko, Wendt and others). Friedberger discovered a similar rod in the mucus of the prepuce of a dog. Frank describes it in the pus of a hog. Frosch found it in the blood of geese, and Beck in an infectious pneumonia of rabbits. It belongs to a widely spread bacterial group. The Bacillus pi/niiciics is non-pathogenic for small, experimen- tal animals and pigeoTis. Since rods similar to those of the Bacillus pyogenes have been fouTid in nuui it is not impossible that affections of man may be produced by milk from udders ^^^th this form of infection. Mastitis. It has not yet been possible to demonstrate this bacillus in mixed milk, since there occur too many bacteria of similar mor- phology in stable manure, in the air, and under the epithelia of the teats. At any rate the milk must be considered as spoiled when it contains secretion from udders with pyogenic infections, and should be excluded from the market, since its injurious effects upon health seem to have been demonstrated in the sense of the pure food act. Infections with bacteria of the coli-typhus group frequently occur when the cows are kept in filthy condition, with unclean bed- ding, and also when manipulations are undertaken by milkers in order to dilate the milk ducts (penetration with straws, quills, and FiR. 23. •^\ v- ' » ^ \ '.^ ^ * ^'^ ' ' ' > . ~i-» t» ->' C'ultiii-cs of Bacillus paratyphus. 1 X 800. (After Kitt.) contaminated milking tubes). Eepresentatives of this group of organisms were described by Jensen and Streit, Guillebeau, Kitt, Freudenreich, Lucet, Sven Wall and Weichel, as the cause of high- ly acute forms of mastitis. The bacteria are short rods. with round- ed ends, inostly motile; they do not take Gram's stain. Accord- ing to their biologic characteristics various varieties may be dis- tinguished, which at times approach more closely to the colon group, at other times more to the serogenes group, aiid at times even to the enteritidis group, which cause meat poisoning. Milk becomes coagulated wltli gas formation. The acidification and coagulation occur earlier with some varieties than with others. The colon group always ferments galactose, glucose, laevulose, mannose, lactoFe, maltose, arabinose, rhamnose, xylose, mannit and sorbit, frequently also sorbose, saccharose, raffinose and dulzit, but not Causes (if Mastitis, 127 erythrit ami a.lonit. Their action is different towards saccharoFe, raffinofe, sorbose aTi.l diiint, aad this iliflereutiation is utilized to separate the Kroups into those which do not attaclc any ot the mentioned liodies, those wliich ferment^ all four, those which split up dub It and sorbose, and finally those splitting up saccharose and raffinose. Of conr-e liactena cannot be strictly separated by their fermentative action, since in the cultivation of rolon strains in sugar .oiitaining media they may acquire the faculty of fermentinff a kind of sugar towards which tliey formerly were refractory (Twort, Massini). Through the (list group the rolon 1 acteria approach the more dangerous group of BciciUus pani- 1i/lihi(s B., BaciUu.<< inUrilidli of (i.-irtiier and jiaracolon hacteria with their related oryiniiMiis, for instance the liiirllliix nitin. i;,i,-iUn-< .-.iiiprsl if, r. B. iiiphi murium, etc. These dangerous groups may be separated by agglutination into three classes, the lUiriUii.i (tilcrilidis c.-iitner group, the Biicilhis piiratiiphtis B. group, and finally the I'ti! ttiiiliiii groupi. Wcichel siK-r-fcdod in isolatiiii;- from two cases of sovere sc]!- tic mastitis an or^nnisiii licloimin,!;- to tho -roni) of Ilacillus oitiii' fidis, and anotlier to the Bacillus }i(irat>iplnis-B. Exehidini;- the intlaiiiniatdi-y piddiifts wiiich may also ]iosscss discas('-producin,n- pro))ortics in this ,<;i'(nip df mastitis forms, it is iiccf'ssary to cxci-cisc siiccial cju'c in the inflammations of the nd- der catised liy tlie ('(ili-cii/crifhlispfiidfj/plnis-pin-aroli oTLfjiiiism^, since amon,^- the represeiittdives of this ni'oup of hticteria there are those whieli may produce se\-ere foi'ms of enteritis in man, -witli symptoms of ]»oisoiiin,n', which are known in uciieral as meat poi- soiiim;-. True parjityjihiis ha<'teria ma\' tilso enter the milk in otluM' ways than with the secretion of an infectcil (|narter, for instance thron,!^'h hacilli-carrieis who are employed for handlini;- the milk, thron,£>-h the rinsing- water, and also from other sources. It will he of interest to mention here the residts of examinations of market milk for the oceurr(>nce of lUicilhis jKirdfi/pluis-B. TThlenhuth and Iliihener twice found paratyjilms in inO sam- )»les, while Iliihener in 40 samples of market milk noted this bacil- lus 4 times a.nd in .">() other sjimples of market milk, ohserved it .'! tinu's. Klein in IVJ mixed milk sam))les found tlu^ Buiilliis cnteriiidis 9 times. The occurrence of coli-aerogenes hacteria in milk would be something- very ordinary, and would lie considered less injurious for the health than the prestuice of varieties which are known as toxin producers. Nevertheless the eoli-aeroiieues infections of the udder should he considered with the greatest care ; although in general the enter- itidis and paratyphus varieties produce severe septic inflammations with ichorims secretions and frequently with a fatal termination, the severity of mastitis and the a]ipearance of the secretion are by no means a certain indication of the character of the infection. ]\Iixed milk to which the secretion from animals with acute af- fect iiuis of the udder has Ijeen added, is spoiled according to the pure food act, and should be considered as capable of injuring human health. The milk of healthy (|iuarters from such infected udders is also 128 Mastitis. suspicious of being contaminated with the infective agents, and therefore should be prohibited from entering the market. According to Weichel reports on paratyphus and enteritidis infections which may be traced to milk are rare, and no publications can be found which absolutely trace affections in man to a coli- paratyphus mastitis. The Dairy Journal of Berlin reported in 1900 that accorcling to "Dag. Nyheter" nine families in Stockholm became affected with symptoms of meat poisoning (fever, depression, fainting spells, nausea, vomiting, diarrhea, muscular cramps). The milk, to the consumption of which the affection was traced, originated from 14 cows, one of which suffered from an inflammation of the udder. In the secretion of the affected udder the same bacteria were found as in the feces of the affected people. Two female attendants of the stable from which the injurious milk was obtained also became affected with similar symptoms. The observation of Moro also belongs here. Moro observed in six persons after the consumption of milk from a goat suffering with a gangrenous inflammation of the udder, chills, nausea, headaches, and 11 hours later colic, vomiting and thirst. The milk was consumed mixed with coffee. Weigmann and Gruber report a case of injurious effect (vomiting), from cream which had been prepared from mastitis milk, and they traced the affection to a bacillus of the colon group (immobilis). Weichel fed a six-weeks old dog with the milk of a goat which was artiflcally infected in the udder with a paratyphus strain from septic mastitis. The feeding was undertaken after the appearance of the mastitis in the goat. Three hours after the consumption of 200 c. c. of the secretion the dog showed marked symptoms of restlessness and barked frequently; lachrymation and later repeated vomiting appeared. He soon recovered but refused to partake again of this milk. Only after 60 c. c. of this fluid had been mixed with 200 c. c. of good milk would he touch it; he then took a small quantity but with apparent distaste. Within five minutes he showed pain, and manifested similar symptoms as the day before, but again recovered before the following day. In a second feeding experiment on a seven-weeks old dachshund the affection commenced only on the fifth day of the experiment. The animal became listless, refused food, whined, and in addition lachrymation, nasal discharge, and periodical chills appeared. This dog also recovered on the second day. Weichel also reports a case in which the wife and daughter of a dairyman became affected with a diarrhea after the ingestion of inflammatory products of a cow with coli-mastitis. The dog of the owner also showed similar symptoms after drinking the milk. As milk offers very favoral^le conditions for the multiplication of bacteria of this group, the danger from milk containing coli- paratyphus bacteria must be considered greater than in the case of meat bearing the same infection. Various data exist relative to the resistance of these bacteria towards influences of heat. According to Fischer heating to 60 dea-. C. for a half hour does not suffice to kill all paratyphus germs; likewise some of the bac- teria remained active after heating the milk for 10 to 35 minutes at 70 deg. or for five minutes at 75 deg. C. Although Kolle states that the typhoid, paratyphoid, and enteritidis bacteria are without exception destroyed when sub- jected to a temperature of 59 dog. C. for 10 minutes," nevertheless it must be remembered that the conditions in milk are markedly dif- ferent than in suspensions of culture, and that some of the varieties are capable of producing a heat-resisting toxin. According to Gart- ner the toxins of the meat-poisoning organisms withstand 100 and ilixcd Infections of I'dder. 129 even 120 deg. C. These facts were confirmed by Van Erraengem, Drigalski, Fischer, Hoffmann, Peels, Hoist, Dhant, Eiemer, and others. In practice therefore it is necessary to consider the mixed milk of the affected cow and all dairy milk to which such milk has been added as injurious to health, whenever it is proven with certainty that it contains secretion from acutely affected quarters. If it is proven with certainty that the secretion contained bac- teria of the paratyphoid or enteritidis group such milk may eVen destroy human health. Of course the danger which threatens man from such milk must not be overestimated. The changes in the udder and in the milk are pronounced and striking, and usually appear very sudden- ly, esijocially in the colon inflammations, somewhat less in para- typhoid and enteritidis infections. Xcvertlielcss in the presence of carelessness of the milker such infections may enter the milk. .Vccoi'ding to Fauss the duration of the elimination of the bacteria from affected udders persists for 12 to ilO days, in fatal cases until death. The number of tlie eliminated bacteria and the duration of Ihe elimination are proportional to tlie severity of the case, and tliey cease when the milk again approaches its normal condition. In other cases of acule mastitis staphylococci have l)een dem- onstrated. Guillebeau isolated the Siaphiilocnccns }nastitidis. GoIactocDCCits versicolor, Gahicfocixciis f)ilriis, and (Idhicfiicucciis aUnis. Expei-imentally it is also i)ossible, as proven by Kitt with the Bofri/ocdccus ascofoniunis (a staiihyloeoecns), to ]iroduce an acute mastitis, with a tendency to chronic develojiment. The staphylococci infections of the parenchyma of the udder are relatively rare, Imt occur more frequently as mixed infections with the Bacilhis pfioiioics. While the course of the staiihyloniyco- sis of the udder is mostly acute, with a favorable progno- sis, yet in the presence of a mixed infection with the Bacilhis pi/nfi- OH's it frequently results in abscess formation and sequestration of the udder. The staphylococci are small round microbes, separated into two or four parts by division. They take the Gram staining. They are easily cultivated on all media and are frequently chromogenic. Tliey liquefy gelatin from the surface do^vn, since they grow better aeroliically than anaerobically. Staphylococci corres]iouding to their ubiquitous distribution are present in almost all milk during its first phases of decomposi- tion ; but although they poss(>ss pathogenic importance as pus-pro- dueers in man, from the standpoint of market milk hygiene, they are nf no special importance under such conditions. However when the secretion of a cow with staphylomycosis of the udder contains staiiliylncdcci, the milk may bo injurious to health. Karlinski, for instance, reports a case of pyemia in a child in which infection 130 Mastitis. resulted from the milk of the mother containing staphylococci. At least the cocci which Karlinski isolated from the milk, and from feces and blood from the child were identical. The secretion there- fore must be considered as spoiled food, and must be excluded from consumption. The same judgment as stated for staphylococci infections also applies to botryomycosis of the udder. This represents a chronic form of a staphylomycosis, in which the single cocci that grow in colonies are compressed by swelling of the cocci lying on the out- er borders, forming capsulated spherical colonies. The central cocci continue to grow, burst the capsules, and the process of the swelling of the bordering zone is renewed until mulberry-like fun- goid colonies result. A method of distinguishing Botryococcus ascoformans from staphylococci has not yet been devised. The botryomycotic formations develop mostly in the horse which is probably proof of certain immunity strength of the horse (that is of equidia), against staphylococci infections. In other animals and also in cattle the disease is extremely rare. Mohler, Czokov, Immel- mann, and Eeinhardt have observed botryomycosis in the udder of cows. Botryomycosis in cattle is of no practical inportance in the judgment of milk. Actinomycosis of the udder is also of slight importance from a practical standpoint. The purulent fibroplastic actinomycotic mastitis occurs in cattle with less frequency than the actinomycosis of other organs. It has been described by Rasmussen (four times), Jensen (20 times). Maxwell (once). Bang, and Johne, and represents a chronic suppuration with nodular cicatrization of the udder. After the in- fection, nodules from a bean to a hen's Qgg in size, with softened centers and fibrous borders develop, or a diffuse inflammation with a tendency toward cicatrization and hardening of the entire udder results. Actinomycosis of the udder may be primary (McPhail, Williamson) and develop from the introduction of barley beards into the tissue, or possibly from pasturing on stubble fields, or again it may develop by metastatic formations from other lesions in the body. McPhail believes that some cases of so-called udder tuberculo- sis are in reality actinomycotic infections of the udder. Should an actinomycotic process soften in the udder and the abscess burst into the secreting tissue, the finding of actinomyces in the milk is possible. The latter appear as colonies of ray-like fungi (streptothrix). The branching threads form a mesh-like mycelium with spherical or club-shaped enlargements on the end of the threads. The fungous threads proliferating in the animal tissue are influenced by the action of the body fluids. The sheaths swell and club-shaped bodies result, arranged in a radiating man- ner, which later become adherent to each other forming rosettes in which the mycelium, protected from the immune bodies and leuco- cytes continues to proliferate or to degenerate and calcify. Actinomycosis. 131 Tlie actiiiomyees are widely spread forms of the higher bac- teria with true l>ranching, and stand between the lower bacteria and hypliomycetes. They almost invariably occur on grain, hay, straw, fruit, manure, soil, flour and milk. Most of the actinomyces are harmless provided a foreign body does not facilitate their col- onization in the animal body. Splinters of wood, and especially beards of barley are frequently the carriers of the infection. Transmission from man to man or from animal to man is not known up to the present time. The basis of an infection always lies in wound infection either through the above mentioned for- eign bodies, or by the fungi gradually becoming accustomed to exis- tence in necrotic tissue of the animal body (caries of teeth). Johne succeeded in producing actinomycosis of the udder through the injection of actinomycotic cultures into the milk cistern. Although transmission to man through milk from actinomy- cotic udders is not to be feared, prohibition of the sale of such milk is required since it must be considered as spoiled on account of the presence of pus and other associated changes. Contrary to actinomycosis, " arfuiobacillosis-" first deseribed by Lignieres and Spitz in Argentina, and which clinically resem- bles actinomycosis, is of a contagious nature. Therefoic although actinohacUlosis has not yet been described in man it should be more carefully judged than actinomycosis. In Germany cases of actin- omycosis have been reported which from the bacteriological find- ings, should be classed as acfiiiohtirillosis, and tlies(> cases occur sometimes in an enzootic form or as stable outbreaks. Thus Imminger in Oberpfalz and Preusse in Western Prussia, described an enzootic extension of actinomycosis, and Scluilze mentioned a case in which the disease affected most of the animals in the stable (of 30 steers '27 were affected). Of 87 newly inirchased animals more than half of those placed in the stable became af- fected, while 12, which had been stabled on other premises and which received the same feed, remained healthy. Milk from udders affected with actifwbaciUosis, and mixed milk which contains such secretion must be considered as spoiled and prohibited from consumption. Mixed infections of the udder with these described bacteria and others, should be similarly judged, and likewise infections with malig-nant edema bacteria, BaciUiis necrophorus, etc. Chaptek VII. EXTERNAL INFLUENCES WHICH ACT UPON MILK. (a) Their effect upon the body, thereby influencing milk secretion ; (b) Their effect upon milk after its secretion. Although our knowledge, relative to the development of the individual components of milk from the substances in the blood, scarcely extends beyond the border of hypothesis, nevertheless it is established that milk formation is dependent to a certain extent upon the feeding, although only within limits defined by the breed, family, individual, lactation period and age. Through outside conditions, those factors of production are especially influenced, ■which are themselves subject to variations, especially the quantity of milk and fat content, less so the proteid and sugar content, and only very slightly the salt content. The influence of feeding could be explained by reasoning that the gland increases its activity at the moment in "which a larger quantity of nutritive sul)stances circulates in the blood, after the ingestion of large quantities of easily digested food. This sup- position could be even enlarged upon by considering that the activ- ity of the cell is stimulated l)y specific substances in the food in such a way that it assimilates to better advantage and in increased quantities the necessary constituents which it draws from the blood. From practical experience and scientific experiments it must be considered as established that the milk produced is dependent both in quantity and quality, upon the quantity of digestible food and on the presence of specific substances which stimulate milk formation. This view has been accepted for a long time by practical dairymen, who for instance have observed that clover hay, in spite of its greater nutritive contents has not come np to the valne of good meadow hay; that meadow hay cannot be replaced l.iy a mixture of straw and concentrated food mixed in a way to make its nutritive value equal to the meadow hay; further that sweet hay proves a better milk producer than sour liay with equal nutriti%'e value, etc. The value of individual pastures also shows wide differences in the production of milk, although examination of the grasses of the pastures gives similar results. In these investigations however it was found that beyond certain limits the influence of nutrition was no longer usable, and that with sufficient feeding of wholesome and tasty food no influence could be exerted upon production through increased rations. 13-2 Elt'ect of Feed on Yield. If animals are allowed to starve, the change in the quality of the milk will result only after the reserve deposits of the body have been utilized to their fullest extent, or completely exhausted. In the state of starvation the milk fat shows an approach in its composi- tion to that of the body fat. If experiments are started with starving animals, or with animals which only receive small rations, the milk yield, according to Kellner, increases with the added increase of feed. Such cows after an increase of rations yielded: With an increase of 1.5 kg. bean bran, the increase of milk amounted to ().!»- and 0..j3 kg. With .") kg. bean bran, the increase was 2.40 and 1.01 kg. A\'ith 1 kg. malt, the increase was 0.S4 and 0.3 kg. AVith '1 kg. malt br;in, the increase was l..'!l and 0.40 ki;-. The increase iu yield liowever was not ])arallel with the in- crease of the ration, but the closer the quantity of milk produced a])])roaebed tlie maximal production of the individual, the slighter liecaiiH' the iiici-ease in yield. In atteiiqtts to increase the ]iroiluc- tion of the cow, the last liter of milk is the most ex]ieiisive. It re- quires for its production the largest addition of rations. In general it may be said that sufficient quantities of digesti- ble proteins are the fundamental requirements for normal milk in'oduction, and that although other food substances are present in sufficient quantities the yield of milk diminishes rapidly when the protein content is decreased below the amount m'cessarv for main- taining the body weight. For 1000 kg. of body wei-lit \ :1V1 kg. of digestible proteins must be figured, together with a sufficient aased 0.25 to 0.32^f . 134 Effect of External Influences. In order to produce an increase of milk it was sufficient to introduce into the food small amounts of fennel, or to sprinkle it with distillate of hay. If in the experiments good meadow hay was fed in sufficient quantities with other food-stuffs, the addition of the stimulating substances was without effect. These observations are of special importance in view of the swindles carried on with milk powders, by which money is still extorted from the farmers. Through the addition of salt to tasteless food an increased yield in milk and fat was obtained amounting to from 20.6 to 21.9%. Hansen reports on the influence of concentrated foods on the milk yield, which he investigated extensively for seven years. This author divides the concentrated food into four groups : 1. Foods which increase the milk yield and diminish the percentage of fat, as for instance farina, corn, oats, and possibly also soja beans. 2. Those which do not influence the quantity of milk but increase the fat content, as for instance palm-seed oil and cocoanut oil cakes (the specific action of cotton-seed meal is less pronounced) peanut meal, corn-slop and bread flour. 3. Those which do not change the yield of milk but reduce the fat content, as for instance, poppy seeds, flour of rice and other concentrated food, beneficial for fattening, as for instance cake of sesame (Eamm). 4. Those which have no specific action, as for instance wheat bran, and malt sprouts. Such food substances are especially de- sirable for the use of fattening dairy cattle. From the experiments of Hansen it appears as a matter of fact, that certain food substances possess a specific action. In this regard the composition of the food is of course of importance, since the action of a certain food may be checked by feeding coun- teracting substances. It has long been known from practical ex- perience that the quality of milk may be greatly influenced through the method of feeding, and not only as far as the constituents of the milk are concerned but also its odor, taste, etc. To what extent food bacteria play a part in this, will be discussed in the chapter devoted to that subject. Summer butter, mountain butter, and stable butter, are richer in fatty acids with low molecular weight, than fall butter or butter from cows which have been kept on low land pastures, or pasture butter in general prepared in the same manner. Feed rich in carbohydrates produces a soft milk fat. If abnormal constituents of fats are artificially added in experimental feeding, or if fats are fed which are otherwise not found in the body, such constituents are again found in the milk, for instance sesame oil (Engel), linseed oil, hemp seed oil (Gogitidse), iodin and iodipin (Caspari and Winternitz), Sudan III, a specific fat coloring matter (Gogitidse). According to Schrodt and Hansen pasture milk on account of its greater contents of casein, contains more phosphoric acid than stalile milk, which on the other hand is richer in chlorin. Accord- ing to Sanson, Hesse and Schaffer the feeding of phosphate also increases the content of phosphoric acid ; this however according Fc'fil Reeomniended. 1.'15 to Xeuniaiin is not immediate but appears only after Aveeks and then in insignificant proportions. Jensen succeeded in findinn,- only an insignificant influence on the milk from the feeding of considera- ble amounts of lactates of iron, calcium sulphate, disodium phos- phate, dicalcium phosphate, dimagnesium phosphate, potassium cliloride, chloride of sodium, and nitrate of potassium. Nitrates appeared in the milk only after 75 gm. of saltpetre had been fed. The administration of from 30 to 40 gm. of saltpetre failed to result in the presence of nitrates in the milk. The salt content of milk tlierefore changes only insignificantly provided normal conditions ai-e present. According to Henseval and Mullie, the health of the animals plays a part when salts pass into the milk. If these authors fed from 5 to 25 gm. of saltpetre to 20 healthy and 8 diseased animals, the milk of the sick animals always contained nitrates, whereas the milk of the liealthy animals did so only exceptionally. Definite quantities of sulphurie acid are supposed to occur in milk after the administration of Glauber salts. Of the various foods, meadow grass, green clover, rowen, green alfalfa, and peas in which a large amount of young gi-ain lias l)een sown are I'ecoramended, for instance, veteh with oats, barley or rye, plants of the white mustard, rape, sainfoin. Kohlrabi tnr- nii)s, etc., with wliich oats, barley or rye have l>een grown. Fod- der or straw should be mixed with the green feed. In the winter instead of green feed, mangels, chopped roots, ensihme, grain, ])otato slop and corn slop should be fed. Relative to the injurious effects of the various baderia round in feeds and pastures, s(>e tlie chapter on milk al)normaHties. (iood liay and good fodder may be r(H'onnnended as drv feed. As con- centrated food the substances mentioned l)y Hansen as indifferent, or those food substances of the first and second group which ai'e recognized as milk and fat pioducers, Avill be found satisfactory. l\ongli fibrous foods cause a loss of energy, and are not well utilized on account of the increased woi'k of mastication and be- cause the intestines are too greatly burdened by this feed. Individ- ual feeding according to the milk yield appears advisable, and the best milkers may be allowed additional rations corresponding to their heavy production. In this regard of course the yield and ([uality of the milk should be established by sample milkings and examination of the secretion. In cow-fattening dairies the fatten- ing of the animals should commence only in the last three months since fattening foods and fattening of the animals diminish the yield of the milk. Pure drinking water has a great influence on milk produc- tion, and the animals should be enabled to partake of it freely ac- cording to tlu'ir needs. Heyken mentions a case in which each cow vieldeil oneduilf liter of milk per day more, when instead of hard marshy spring water containing iron, good well water was sub- 136 Effect of External Influences. stituted. Backliaus observed an increase of milk and fat con- tent after the introduction of an automatic water supply. Milk of poor quality is known to have resulted from the use of poor drinking water. Stagnant waters give the milk a repulsive taste. Taken as a whole all foods and all food mixtures which are par- taken of and digested by the animals without disturbance in their general condition are adapted to the feeding of milk animals. Food which in continuous feeding causes diarrhea or other intestinal disturbances should be avoided. Intestinal disturbances which quickly subside and which sometimes develop as a result of sudden change of food are of no consequence in the judgment of the food. They may cause considerable fluctuation in the jdeld of milk and fat content, which however subsides in a few days. From the above statement it will be seen that under certain conditions, espe- cially when a heavy production of cream is necessary, the effects of a change of food must be considered. If, when considering evidence of adulteration, methods of examination are used which take note of the approximately constant factors in milk, that is, such as pertain to the protein-free milk serum, the influence of a feeding method, or a sudden change of feed should be taken into consideration in regard to its effect upon the milk of each indi- vidual animal. Spoiled food injures the taste and odor of the milk and butter, and its effects may last for a long period after the time of feeding such food. The feeding of large quantities of beet or tur- nip tops should be guarded against, likewise over feeding with fresh or sour chopped roots, potato slops, residues from starch factories, brewer's grains, rape seed cake, flaxseed meal and poor straw. The taste is improved by feeding on pasturage, red clover, meadow grass, carrots, oats and rice flour. Firm tallowy butter is derived from grass of acid soil, from grass from fall pastures, late hay made from sour grasses, leaves of sugar-beets, or red beets, chopped roots, potatoes, peas, palm seeds, cocoanut and flaxseed cake, and cotton-seed meal. Soft butter results from the feeding of oat hulls, corn bran, wheat bran, rice flour, rape-seed cake and sunflower-seed cake. Clover pastures are not suitable for the production of milk for cheese making since the cheese becomes permeated with small holes, and has a sharp repulsive odor. This condition is probably brought about by bacteria which vegetate on the clover plants of the pasture. Changes from one feed to another should not be made too sud- denly if it is desired to prevent an effect on the milk production. Newly introduced food substances should not be fed in large quantities at first. In changing from dry food to pastures a dimin- ished milk yield first results, then a period of normal yield and Plants Affecting Milk. i;',7 finally an incvcase in the quantity, together with an improvement in quality. Pastures or green cultivated forage containing many buttercups should be avoided, since these plants are supposed to produce red and bitter milk, especially before blooming. Meadows or pastures in which Euphorbia plants are growing exert a bad influence ; they may produce enteritis with a fetid diarrhea, also paralysis of the bladder and hematuria, and may even cause abor- tion. The milk turns thin and bluish. Bluish milk may also result after feeding upon plants of the Polygonima species, the ox tongue (Anchusa offic), the cat's tail (Rutomus umbellatus), the euphorbia (]\rercuriahs), the maish marigold (Rhinanthus major), the forget-me-not (]\lyosotis), and after feeding upon poppy-cake and green alfalfa. Red milk is produced by feeding blood root (Galium verum), madder (Rubia tinctontm), species of Karcx, Skirpus, Equisctum, Ranunculus, Euphorbia and after tlie ingestion of youni;- s])r(iuts of both deciduous and coniferous trees. Yellow milk results from the elimination of plant coloring matter after tlie feeding of carrots, rhubarb, yellow and reil uian- g<'ls, and crocus. A garlicky taste may also result from feeding lar^e quantities of poor straw, and aeeording to "W'erenskiold aftei' feeding of flax seed meal which contains largo quantities of wee(l-see(ls, iteniiy- royal (Thlas]n arvense). The tastt' of the milk may aNo ])o changed by the ethereal oils of the I'ollowini;- i)lants: Garlic (Alium ursinum), mint (Teukrium), hyssoji (Oratiola offic), true camomik' (]\Iatric. chamomilla), and by rape, rMpe- cake, oil cake, turnip tops, lupins and orchids. i\tilk may become fishy from feeding lish meal and throui;li pasinring on nmrsliy fields which have been inundated. ]\lilk turns bitter from feeding kale, rutabagas, turnip tops, lupins, pea-straw, lupin straw, and sorrel. A bitter substance from chicory passes into the milk; the milk mav coagulate more readily after the ingestion of thistles or sori'el. The ingestion of euphorbia, hellebore, rushes, and hemlock twigs should be prevented on account of the poisonous qualities of these plants. The secretion of the active poisons of these plants has, however, not been proved. Hop leaves, especially tho>e spraved with coiii^er sulphate, cause a diminution of milk secre- tion, or even a cessation of the flow. Concerning the elimination of medicinal agents with the milk, or the influence of medicinal agents on milk production the follow- inii' may be stated : The ]iassage of iodine into the milk after feed- ing ]iotnssium iodide has been proved In- Peligot and Stumpf ; if iKAvever the iodine is fed in alkaline compounds, or combined with proteins and starches, even when fed in large quantities, it does not pass into the milk. In the latter case only the plasma of the milk 138 Effect of External Influences. contains the halogen in the form of a salt, whereas in feeding iodized fats the milk fat contains iodine. According to Eosenhanpt and Bncura the same applies to bromine. According to Stumpf, Baum and Seeliger, in feeding com- pounds of lead small quantities (0.02%) of this substance pass into the milk. The ingestion of such milk was found harmless for ani- mals. The lead was eliminated for a longer period than the time during which it was fed. Milk which contains salts of lead could produce severe injurious effects if taken for a long time (chronic lead poisoning). Feeding of salts of copper results only in the appearance of traces of copper in the milk. The feeding of iron preparations does not to any noteworthy extent influence the contents of the milk. Mercury may pass into the milk (Bucura) ; likewise arsenic when administered per os or injected in any form subcutaneously (Bucura, Ittalie and Jesionek). Substances like aloes, senna leaves, rhubarb and croton may influence the milk in color and taste, and will be partially eliminated with the milk. According to Eost and Wiley boracic acid may pass into human milk; likewise after the ingestion of Grlauber salts the SO3 content of the milk is supposed to be increased (Hess and Schaffer). According to Baum tartar emetic is not found in the milk of cows treated with this drug, whereas Harms claims it is eliminated with the milk. The feeding of large quantities of alcohol effects a diminution of the specific gravity and an increase of the fat content of the milk. The quantity of the milk appears somewhat increased (in goats). Elimination of alcohol with the milk does not occur. Wel- ler and Teichert proved that alcohol would pass into the milk of cows after feeding them with large quantities of incompletely ex- tracted distillery slops. Although Horder and Herdegen claim the secretion of salicylic acid with the milk, Eichter, Pauli and Stumpf disclaim ' its elimination in large amounts. Pauli and Stumpf succeeded in de- tecting small quantities of salicylic acid in the milk of nursing mothers treated with this substance, and also in the urine of their babies, as well as in the milk of experimental goats. In this regard individual peculiarities must also be considered since in one nurs- ing mother the presence of salicylic acid was demonstrated, where- as the examination was negative in another case. According to Pinzoni the same applies to antipyrin. Salol does not appear in the milk after its administration. Chloroform and ether are found in considerable quantities in the milk after anesthesia (Nicloux). Druiis affecting ililk. 139 Landsberg failed to detect morphine in the blood, nrine or in the organs, either after subcutaneous or intravenous injections, and Stumpf and Pinzoni do not believe that after therapeutical administration of morphine it will pass into the milk in demon- strable quantities. This was found by Ittalie to be the case with opium. Oil of turpentine is not eliminated with the milk (Ittalie), and the same is true of santonin (Coronedi). Stumpf undertook experiments with pilocarpin Avithout how- ever Ijeing able to tind the pilocarpin in the milk, although his methods were unsatisfactory. Atropin and fluorescin administered subcutaneously, accord- ing to Fngin and Bonanni, and Ittalie, may be demonstrated in the milk. It should also be mentioned here that accord ing to Ostertacj meat of poisoned animals may be eaten without harm to the health. He established the fact that meat from animals which have received medicinal agents for therapeutic purposes may be consumed without any possibility of danger. The harndessness of the meat of poisoned animals has been (•stal)]ished by Prbhner and Knndsen for stry(diiiia, eserin, ])ilocarpin and vciatrin; by Harms for nux vomica and tartar emotii-; by Feser for strychnine and eserin; by Spallanzini and Zappa and Sonneiisrln'iu for arsenic; by Gautier for cotton- seed cake; by Feser for apomorphine; by J'ps(diid for colchicum; by Warnke for morphine; and Albrecht for litharge. Of course milk may contain certain quantities of poison since the udder ha^^ a special i'linction as an cxcrctoi y organ. The i|uestioii of eliruination of medicinal renicdio-i, however, is not of practical iuiportance since the medicinal doses are relatively small and their elimination occurs only in traces. In this entire question milk inspection is powerless. Tlirough educational advice liy the consulting veterinarian ilic produrcrs may lie reminded of tlieir duty corri^siioiiding to tlic proliibitive measures, not to include with milk for the market that produced by animals which are under treatment with certain drugs. From a hygienic standpoint only those remedi(>s deserve mention which are eliminated for a long period after their administration, as for instance lead and medicines whose prolonged ingestion may pro- duce disturbances of health even in the smallest doses. Considering the fact that in normal feeding with good feeds (if any kind the individual influence is paramount in milk produc- tion, it becomes evident that in estabhshing regulations for pro- curing children's milk more stress should be laid on the health of the animals, on good attendance and care by healthy milkers, and (in thorough cleanliness of the stable, and cleanliness in procuring and handling the milk, than on rigorous regulations for feedin<;- which cannot be satisfactorily carried out by the owner on economic grounds, since he must utilize the by-products or refuse of any industry of his vicinity. There is no reason why ]iasture milk, or milk obtained after feeding gi(>en food should be excluded from the market as certitied oi- children's milk, especially if from a dietetical standpoint the advantages of green feeds for cattle are considered, and the favora- 14:0 Effect of External Influences. ble influence which the pasturing exerts on milk production and metabolism be regarded. Spoiled feed should be prohibited, and also foods which are readily subject to decomposition (fresh residues of breweries, sugar refineries, etc.). Food which is obtained through fermenta- tion processes (hay, grass, clover, mangels, potatoes, green corn, stored in pits in the ground) should if possible be limited, since substances of odor and taste are eliminated with the milk and especially food bacteria which diminish the keeping qualities of the milk. Although they might not liave a direct harmful influence in the human organism nevertheless they may spoil the taste of the milk. The beneficial influence of pasturage cannot alone be attributed to the advantage of change of feeding, but is also the result of the stimulating action of the light and air on metabolism, and of the mild form of exercise. Therefore in the absence of pastures it Avould be advisable to provide exercising paddocks for the animals. According to Munk moderate exercise increases the yield of milk and its proportion of solid substances. Excessive exercise of cows should be avoided. Although moderate exercise on rich pastures in connection with other factors which increase metabolism, produces more alrandant and richer milk, increased exercise reduces the quantity of milk but increases its fat contents. In over-exertion however the quantity and quality of the milk are reduced, and the milk and butter both develop an irritating taste (Dolgich). Exhausting transportation changes the milk production con- siderably, especially when during that period the cows are milked irregularly, or for advantage in selling the cows the udders are allowed to become engorged with milk. Stasis mastitis results, which may be cured only by repeated and thorough milkings. Excitement of any kind, such as fright, taking away the calf, change of surroundings (new purchaser), and change of feed, may for a longer or shorter period cause a diminution of the quantity of milk and a change of its quality. Backhaus observed an increase of over 7% in quantity of milk production and 8% of the fat content after the cows had iDcen curried; in other cases it amounted to 4 and 2i^%, respectively. In pasturing cows, sheds should be provided for shelter from the strong rays of the sun and rain ; otherwise according to Schwenk the yield becomes diminished. Kirsten observed a dimin- ution of the production of milk after prolonged rain. According to Ingersoll and Duncanson, marked changes in the weather may even he of significance during the season when the animals are stabled. A rise or a fall in the temperature may cause a reduc- tion in the fat content. In the morning following rainy nights the milk may become richer. The influence of weather and pasture on Method of Stablintr. l-tl milk production has been observed by various German investiga- tors, but the results differed considerably. Some observed a dimin- ution of the fat content, others an increase, while some noted a diminution of the milk yield, and a number of others detected no reaction whatsoever. Following the passage of a heavy thunder shower a diminution of the milk yield and an increase of the fat content were observed which corresponded to the increased activity of the animal in the equalization of the body heat. If herds which are pastured at night are compared with those which are stabled at night, no favorable influence of the stabling at night is observed, neither regarding the quantity of milk nor its fat content. In animals kept uninterruptedly out of doors the fat content increased more rapidly than in those kept in stables. In the foriucr the live Aveight increased more rapidly than in the latter; in other experiments, however, the results remained the same. AVyehgram in his experiments in East Friesland found the milk yield in stabled animals increased, but the fat content diminished as compare(l to milk from cows at pasture. The cows which furnish the milk supply of cities as a rule are kept in large stables. The stabling of course should be such that the health of tlie animals does not suffer, and means should be provided for a pure milk production. It is not so difficult to comply Avith these two requirements as some farmers believe. They may l}e attained Avitliout great aib ditional cost, since the increase of exiieiise fur ])r(iper stabling is amply covered l)y the increased income from the animals. In equipping so-called model stables, an extraordinary amount is usually expeu(l(>d for luxury in the e(|uipment and furnishinus, so that the practical farmer on visiting such stables is fi-(Miuently disheartened, instead of being encouraii'ed to chanue his move primitive place of milk production to comply with these models, since a simple calculation of the ex])ens(^ of such buildings for kee])- ing cows shows him that a change of his stable conditions to equal those of the models is impossible. A reallv valuable modern stable however may be built at the present time without considerable additional cost, and may Ik- cm luipped so that the additional expense of milk production due to the wearing out of the building is not greater than the cost of repairing an unsanitary stable. For the erection of a new stable a dry buildino- site should be chosen if possilile, or at least the penetration of dampness from the o-round should be prevented through separation and isolation of The ground and walls. Only under such conditions can the require- meiit of clean Avails be attained. The floor of the stable must be Avater tight and AA'ithout cracks and h.>les, and should permit of ready cleansing and disinfection. Tt is to be regretted that such Avater tight floors are frequently too cold for milk cows, and the action of the cold must be diminished 142 Effect of External Influences. by the provision of wooden planks. The floor surface must be rough enough to afford tlie animals a solid footing. The walls of the stable should be provided to a height of 6 feet with an unpenetrable, washable covering, which however should not be dark as was customary in the past, in order to hide the ac- cumulated dirt, but should be light in order that dirt may be readily seen and removed. The stable ceiling should be separated from the feed loft situated above it, by an air space, and should be whitewashed, the same as the walls. In order that it should be impervious to the sta- ble odors, the ceiling on the inside of the stable should be covered with minerally treated pasteboard. The air space between the ceiling and feed loft should communicate with the outside air. Angles and corners should be rounded off, in order to prevent the accumulation of dust. In large herds the erection of several small separated stables should be given preference to a large single stable for all animals. Each of the stables should be made for 16 to 20 animals. The advantages of the smaller buildings are manifested in better pos- sibilities of ventilation, the easier removal of manure, cheaper con- struction of the roofs, less excitement for the animals, and better possibility of caring for and feeding the individuals. Against these advantages the absence of close supervision, which is afforded by the large stable, is not material (Schuppli). The animals should be placed in rows in such a way that the light may strike them from the side or from the rear. In order to provide a great amount of light, high, broad win- dows and transparent instead of only translucent window glass should be installed, the total lighting surface of which should amount to at least one-twentieth of the floor space of the stable (according to Schlossmann the comparison should not be much less than one-fifth). Placing the animals face to face should be avoided on account of the danger of infection with tuberculosis, or this danger should at least be diminished by broadening the passages. The windows should commence from 5 to 6 feet from the floor. Artificial illumination should be provided for ; transoms assist in the airing of the stable by allowing ingress of natural atmosphere. The ventilation should be calculated so that the air of the sta- ble should not contain more than 3:1000 (Marker), or 1:1000 (Schlossmann) carbonic acid. According to Schlossmann a cow weighing 1,100 lbs. produces 12.71 cubic feet of carbonic acid, which would have to be diluted by 1,000 times its quantity of in- troduced air in order to contain only 1 :1000 of the required quan- tity in the air. This introduction of air is made possible by three changes of air per hour, without permitting a disturbing draught. Therefore, according to Schlossmann, the air space in a stable for cows weighing 1,100 lbs. must be 12,710 :72=176.5 cubic feet. Gen- Stable Construction. 143 erally however, on account of economic grounds a mucli smaller air space has to answer the purpose. Schuppli even believes that a reduction of air space below the ordinary 70 to 88 cubic feet of air per animal would be permissible when the ventilation system is working- properlj^ and is satisfied with 42 cubic feet per animal when the ventilation providos for sufficient renewal of air. The supply of air is provided by wide shafts which take the air from the outside at a height of three feet, lead it up through the wall and oxitcl it from the stable ceiling into the stable. The foul air eseapos through an opening close to the stable floor of one or more discliarge shafts, which are carried to the highest point of the stable ceiling, or sideways from the median line iipwards and outwards. Tlic total capacity of the discharge shafts should be somewhat smaller than the capacity of the supply shafts. In intousivo ventilation, esjieeially when the air s])ace provided for each cow is consideralile, lieating of the stable might liecome necessary, a provision which of course could not be considered for the ordinary, medium-sized or even larger establishments. Well-installe(I transom ventilators, if sufficient attention is given to tbeir operation, would supply the desired change of air even without heating, and at the same time maintain the desired temperature of 16° to 18° C If heating is provided the air sn))- ply shafts should open over the heaters. In providing stalls, from the standpoint of eleardiness only the so-called Holland type of stal)le floor should be recommendeil for dairy stables. The principle on which tli<'se are built coIlsist^ of rather short standing space with broad, dee)i dininage tr(uigh in the rear. The urine and manure falls into this trough, and soiling of the animal is thereby prevented Avhile the contamination of the bedding is minimal. Among objections to the Holland tyjio of stables, it is sometimes claimeil that the animals cannot move snfficiently and tliat such stablinw constitutes a cruelty to the animals, etc. The best proofs against these objections without doubt, are the facts that in countries which are in the hicrhest state of asricultural development this method of stabling has been practiced for a long time, and the animals soon get used to thi>< method of stabling without suffering in their general condition or being affected in their milk production. In the Holland method the tails of the animals are tied with a cord in such a way that while the animal stands its tail hangs in a natural position', but when lying down the tail is kept_ elevated so that it cannot lie submerged in the contents of the drain. The cords are tied to a rod which runs near the ceiling, parallel with the row of cows, or the cords, with weights attached, are allowed to hang over this rod. The shortness of the stalls of course requires a low feeding trough, over which the animals may extend their heads while lying down. In order that the animals may not annoy each other, the individuals are si-parated by means of partitions, which extend J44 Effect of External Influences. upwards to the height of the head or the shoulder and at the same time have fastenings which are used for tying the cows. To prevent the cows from hacking into the drain, a moulding of one-half inch is provided along the upper border of the drain trough. This moulding holds the slipping foot and makes possible the placing on the floor of w^ooden slats when pregnant animals are about to calve. The fundamental principle against the possibility of slipping is the above-mentioned provision of a sufficiently rough stable floor. The width of the stalls should be about Sy^ feet, the length 5l^ to 5% feet. The most satisfactory feeding troughs are those which cor- respond to the conditions of natural feeding in the pasture, and they should be so constructed that they will serve for animals of all ages with the possibility of providing partitions in order to separate the individual rations. For watering the animals it is advisable to provide each stall with automatic water supply. The accumulated litter in the drain trough should be mechan- ically removed as often as possible into liquid manure pits which terminate in a tunnel with collecting canals, or the litter may be thrown into a chute through a shaft leading to a water-tight liquid manure pit the size of which should be so arranged that 88 to 106 cubic feet of manure space are allowed for each animal. Over the liquid manure pit on wooden lattice frames, or along- side of it, should be placed the manure pile, with 30 square feet of surface for each grown animal. On account of the desired decom- position of the material the first-mentioned arrangement of the manure over the liquid manure pit is most desirable. There should be a separation between the stable and the mantire pile of at least 20 feet and the latter should be placed on the side opposite to the principal direction of the wind in that locality. The outlets of the manure drains should be closed from the stable liy trap or slid- ing doors. Good straw should be selected for the bedding of animals. The question of straw which is very important in localities where but little is grown is favorably solved by the Holland method of stabhng, since by this method a great deal of straw is saved by the short stalls with but slight soiling of the animals. Forest and shade leaves are not recommended, since it is claimed that milk troubles result from their use. Turf straw, shavings and saw- dust should Ije avoided if possible on account of the formation of dust, but should not be excluded if good straw bedding cannot be obtained. The use of bed straw should be prohibited in milk stables. The feeding of the cattle must be performed after milking, on account of raising the dust. The removal of the manure and the cleaning of the animals should take place at least one hour be- fore the milking. Complaint is frequently made to hygienists that the require- Curaplete ^Milking. 14.3 ments wliich are made by tliem relative to stable hygiene must in- crease the cost of keei^ing the animals, and thereby increase the cost of the milk. This view is only justified to a slight extent. Stable hygiene if satisfactorily adjusted will result in a considera- ble increase in the yield of the dairy animals. The economic losses which are induced by udder affections, which spread with especial rapidity in filthy stables and from unclean milking, have been discussed in a special chapter. Atten- tion should only be directed liore to the increased production fol- lowing proper attention to cleanliness of the animals, and to the findings of Bloymeyer and others, according to which cows in well ventilated stal)les, all other things being equal, yielded from 450 to 4S0 liters more milk per head each year than cows kejot in unvcn- tilated stables. The favorable influence of exercise and light work has also liccn discussed above. If jtossible the animals should be ,<;iven an opportunity to run out of doors in a paddock for at least one to two hours daily, even in the winter months. Of all outside influences, icgular and complete milking con- stitutes tlie most prominent stimulant for inducing the activity of the lulder. It is known that cows which are milked tlirec or four times in each twenty-four hours give more miflv than those whicli ar(> milked only twice (Backhans). The increased yield fi'om milk- ing three times amounts to from 10 to 1')' r nmre than the ])ro- duction obtained from two milkings; in four milkinn's the increuM' amounts to from 6 to S% as coinpared with thice milkiniis. The quantity and composition of the milk at each milkim;- de- ]»end somewhat upon the time which has elapsed since the la^t milk- ing. According to general exi)erience the morning milk is of greater quantity with a smaller anmunt of fat, in comparison with quantity and fat content of ihv evening milk. During the ni.nht absolute rest prevails, whereas during the clay the influence of light and motion causes an increase ot nu^tabolism whi<'h is also mani- fested in the variations of the body temperature shown by the animal in the morning and evening. The differences in milk, which are obvious in irreg-ular or so-called broken milkings, may be explained in a dift'erent way : tliat is while the milk at the beginning of the milking contains 0..") to 1..")'"^ fat, in the middle of the milking it shows 2 to ;] to 4%, and ai^ain rises towards the end, durin<;- the last strokes of milking to S and 10^^ CMelander, Kaull, Cotta, de Vrieze). The fat-free solid substances are subj(>ct to slight changes (according to Boussin- gault the fluctuation amounts to from 0.2 to 0.2S'~f ). The condi- tions in the milk when the calf sucks are similar. .\ truly plausible ex]ilanation can hanllv be given to the supposition of a separation of iToam intho u.lilor ( Zsoliokke) : likewise it hardly seem-- reasonable to siippc^e that the thill ]4asnia jiartieles flow towards the ci^teni, while the fat u'lnlmles a's a result of trieatiT fusion ami friition are retained, and are only pressed towards the larger milk dints and the .-istcrn liy the newly forme. 1 milk which is secreted during the act of 10 ]46 Effect of External Influences. milking. The principal cause lies probably in the fact that the separation of the fat represents a greater expenditure of energy than the secretion of the plasma. If the cell is exhausted by previous milking it then secretes milk during the period of rest which is especially rich in plasma and poor in fat. Through this period the alveoli and milk ducts are dilated, and the gland cell becomes flat and is at rest. In this position of rest it recovers and is ready for renewed action when, through renewed milking operations, the fluid is withdrawn and stimulation of the secretion is applied through the teat. If the milk is removed without this stimulation of secretion, with the aid of a milking tube, only milk poor in fat flows from the cistern and the larger milk ducts, and the flow ceases as soon as pressure is no longer exerted on the secretion. If, however, through milking (or other stimulation) new secretion takes place, the rested gland cell engorges with nutritive material, and converts it into fat, which is separated during the milking in increased quantities until the secretion of plasma and the separation of fat cease, which marks the height of these two processes in the secretion of milk. Through an increased stimulation by additional milkings the cell may be further stimulated to a special production, which consists in an increased fat formation (Hegelund). Henkel succeeded by this procedure, in increasing the quantity of milk by 2.4%, and the fat content by 6.2%. As already mentioned Hegelund 's method requires additional work, Avliicli may possibly lead to tlie hiring of additional help and must be considered (Kirchner), when estimating- profit and expense. The principal factor in the various methods of milking lies in the thorough milking out of the udder, which will retain its maximum of production only by such practice. Henkel suc- ceeded in demonstrating the extent to which the milk production de- pends on the thoroughness of the milker. The production of a cow when milked by a thorough milker amounted to 8.1 kg. (17.8 lbs.) of milk, with 4.2% of fat; by a less satisfactory employee to onlv 5.6 kg. (12.31bs) with 2.7% of fat. At the same time it is immaterial what method of milking is pursued, that is, whether the teats are milked crosswise, or those on one side, or those of opposite quarters, simultaneously. Milk- ing of a single teat at a time, which of course is not customary, yields less milk, and the last milked quarter is the poorest in fat (Lepoutre and Babcock). The influence of special methods of milk- ing has been more fully discussed in the chapter on the procuring of milk. According to Klinkmiiller the milk yield of the right half of the udder is 3.97 kg. (8.7 lbs.), the left 3.65 kg. (8.03 lbs.), with fat contents of 3.65 and 3.31% respectively. The cause of this increased production of the right half of tlie udder is, according to Klinkmiiller, the result of the practice of milking the right half first, and therefore it is advisable to practice alternation in milking, from right and left. If milking stools are used care should be taken that the milkers do not take hold of the seat with their hands. The most recommendable stools have only a single foot, and are secured around the body by a strap. Switching" of the animal's tail must be prevented during milking by tying it up, or by other effective contrivances. Conditions Avhich prevail in the handling of milk after it has been procured are of special importance in providing milk of the best quality. The changes which milk undergoes have been dis- Milk Pails. 147 cussed sufficiently for the purpose of milk liy^ene in special chap- ters. Those points principally should be emphasized which are to be followed during- the drawing and preparation of the milk, in order to check or prevent undesirable and early decomposition of the product. This relates primarily to cleanliness. The requirements of milk hygiene go hand in hand in this respect with the purely economic requirements of the dairy industry. If it is considered how much milk spoils prematurely on ac- count of improper care and the amount of loss which is sustained when the creameries have to discard hundreds of pounds of cheese on account of improijcr handling of milk, then the economic value of cleanliness in the stable becomes obvious. The Holland method of stal)ling, cleaning of the cows and especially the udders are quite simple but important factors in such cleanliness. In keeping the udder clean special attention should be given towards preventing its contact with tilth. Dry cleaning with suitable straw, or rough towel is prefera- ble to moist washing which often consists in sjireading the sol'tenecl dirt over the entire udder. If the dry method of cleaning tin' ud- der is used such milking pails should be jnovided which will pre- vent the milk from becoming contaniiiiated Ity the dust originating frtJin the cleaned udder. If the udders are washed it should be done with hikewanu water withoiit S(tai). Subsequently the udders should lie rul)bed of carbonic acid, hydrogen and sulphide of hydrog(^n, and supplies the milk with air, so that in all probability the development of certain bacteria is checked, which otherwise, if the milk had lieen fille(l into (-1)11- tainers in a warm and un-aerated condition, would have imparted to the milk a sharp, disagreeable animal taste and odor; the milk would have been "suffocated." The corrugated surface coolers are especially suitable for use in small dairies. The cans into which the milk is filled after cooling should be tinned in a satisfactory manner. It is to be regretted, however, that this is the case only with new cans. The tin covering espe- cially on the places where the outside strengthening bands are placed, is very imjierfect, and after a shorter or longer time defects in the lining develop, which soon result in an extensive formation of rust. The oxidation of the iron finally results in tears and holes which produce deep, sharply circumscribed depres- sions in the side of the can in which rust, decomposed milk and slime accumulates. The transportation of milk in rusty cans, or those in which the lining has become damaged, gives it a disagreeable tallowy' taste. Milk shtnild be protected from bright light. Sun rays and indirect daylight may give the milk a tallo^^T rancid odor and Chapter VIII. BACTERIA IN MARKET MILK; THEIR ORIGIN AND ACTION. Before milking is commenced the ndder sliould be cleansed of all adhering dirt. Cleanliness in milking is one of the most important factors in giving the milk good keeping qualities. Sub- sequent cleansing through straining, filtration, centrifugaliza- tion, etc., is of little purpose after the dirt particles (straw, manure, dirt) have once imparted to the milk their soluble con- stituents, and an actual inoculation has been accomplished with the bacteria of filth. The tail of the cow should be tied, in order to prevent bacteria from the skin being thrown into the milk by its switching. If left free it may even subject the milk to contamination with coarser substances. The importance of the effect on human health of bacteria which fall into the milk, and which multiply therein when milk is improperly procured, is not known, but the thought is at least repulsive when it is considered that milk consists of a manure sus- pension of a bacterial culture, and on this ground alone absolute cleanliness in milking should be insisted upon. In order to attain this it is again necessary to provide a properly ventilated and well kept stable, as well as milk room. The veterinarians can in no way obtain a better recognition of the milk problem than by always pointing out to the farmer the necessity of keeping healthy cows in properly constructed and well-kept stables, and in impressing upon him the fact that the procuring of pure milk and its proper handling constitute the fundamental principles of a prosperous development of the milk industry in general, and not for the milk supply of the city alone. Many farmers, espe- cially the small ones, can only be convinced by practical demon- strations of the advantages to be derived from proper stabling and care, and therefore it is our duty to win over reasonable and progressive farmers to the erection of model dairies, and to offer to the smaller farmer the aid and advice by which he can improve his condition with the least expenditure. Even if nothing more than diligence, attention and a feeling of responsibility are aroused these alone would mean a tremendous improvement over the con- ditions prevailing at the present time. It is evident that if no special milk rooms are provided every- 152 Procuring Sterile Milk. 153 thing should be avoided during milking which would cause stirring up of the dust, such as removal of manure and feeding. As long as the milk gland is in a healthy condition the cells secrete a sterile product, which becomes contaminated with bacteria only in the lowest part of the teats, in their ducts, or during the process of milking, etc. Bacteria arc always present in the lowest parts of the ducts of the cistern, as a result of contamination from the litter. These bacteria and also those which fall into the milk during milking, and the massaging of the quarter, render the procuring of sterile milk practically impossible, even when the strictest care is taken to prevent as far as possible the subsequent contamination of the milk. In spite of opposing viows, it may be considered proved at the ])res(!nt time that the milk in tlie udder is sterile as long as tlic animal is not affected with diseases of the udder or severe general affections. Lister, Miessner, Eselierieli, Kitt, Tromms- dorff, Rullmann, Seibold and otliers succeeded in procuring abso- 'iitely sterile milk. This, of course, was only in small quanti- ties, and drawn with special care, such as wasliiiig the udder, disinfection, protective covers, etc. The first streams of milk are of course always contaminated with bacteria (Schulz, Luz, d'Heil); the subse(niiMit ones nmy l)e sterile, but fre(|uently they also may contain liaeteria, as eontirineil by the works of Boekhout, Ott de \'ries, Ward, Koning, and Frendenreich. In practice the procuring of milk with a moderate number of bacteria must be considered satisfactory. Schulz, for instance, found that the first milk ]irocured contained .")."),.')(;(> up to 1'7,L'40 bacteria per c. c, wliil(> during the middle of the milking it contained only 2,070 to 9,98;"), and in the last from to JOO bacteria. In an interrupted milking, that is, when the milk was ol)tained in four portions, Backhaus and A]ipel counted in the first part 170 to 950, in the second 60 to 255, in the third 10 to 70, in the fourth to 45 bacteria per c. c. For procuring sterile milk the followinfj measures are recommenderl: Washing the udder with soap and water, disinfection with alcohol (Kitt, Kolle) ; disinfection with mercuric chloride solution (Fauss, Klimmer) ; mercuric chloride solution and rinsing with lioriU'ic water and formalin (Boekhout and de Vries) ; washing: with a -% mercuryo.xycyauide soap (Frendenreich), followed with rubbing with sterile cotton I O-^tcitiif,') ; salirvlcottoii (Eichert); sterile cloths (Freudenreich) ; and then after cleaning and thoroughly disinfecting the hands of the milker with soap, water and the s.-iiiic disinfecting agent whi(di has been used for disinfection of the udder, the milk may be carefully drawn by the usual method, which is termed ■ 'fisting." Backhaus after a coarse cleaning of the udder, covers it with a bag which con- tains disinfecting fluids. After a short action of the disinfectant the fluid is allowed to csiape through a stop-cock attached at the lower part of the bag and the udder is rinsed with previously boiled warm water. Other authors cover the body of the animal with slici'ts. leaving oidy the udder exposed. Boekhout, Ott de Vries and Trommsdorff used sterile milking tubes for taking ^;itii|i|c's. In this operation it is to be regretted that even in the most careful manipulation with sterile milking tubes, infections of the uilder sometimes result. Rullmann therefore )iri'l'iTs diir.t milking. He also rubs white paraffin salve into the skin of the surround- ing part of the udder. 154 Bacteria in Market Milk. Through such protective measures individual authors obtained the following results : Freudenreich : 200 to 300 bacteria per c. c. Szasz: 2 sterile, 11 with an average of about 2,700 bacteria. Hesse : 1,600 bacteria per c. c. Marshall : 295 bacteria per c. c. Lux : to 97 to 6,800 bacteria per c. c. Kolle: 80 to 15,000; in 33% of the experiments the counts were below 300 bacteria per e. c, 50% below 500, others up to 800 per c. c. Only 4.7% yielded 700 to 800 bacteria. Willem and Minne : 1 to 5 bacteria per c. c. Willem and Miele : to 37, 4 to 218 bacteria, respectively. Seibold studied the bacterial content of the milk under the rnost varied experimental methods, and especially under condi- tions which correspond most nearly to those prevailing in practice. 1. Without protective measures. 2. After soaping the udder. 3. After soaping and disinfecting Avith alcohol. 4. After repeated disinfection with alcohol, and procuring through sterile milking tubes. The poorest results were obtained, as would be expected, by the first method, and the best results by the fourth method, with which it was frequently possible to obtain completely sterile samples. The number of bacteria by the fourth method fluctuated between and 12, by the third between and 85, and by the second between and 434 per c. c. The first method produced samples of milk with less than 10 up to several thousand bacteria. Trommsdorff and Eullmann observed in samples which had been procured without special precautionary measures, such as cleaning of the udder and hands, on an average (96 samples) 6,700 bacteria per c. c, but only 1,500 bacteria when a thorough cleaning of the udder and of the hands of the milker had been undertaken. Seibold, Trommsdorff and Eullmann found in individual cases an enormously high bacterial content even in freshly pro- cured milk, the colonies on the plates containing mostly strepto- cocci. These samples were obtained from cases of inflammation of the udder, and the milk was already contaminated with streptococci before leaving the udder. These organisms would not otherwise be present in aseptically procured milk (Seibold). As it IS difficult, even under the strictest conditions, to procure sterile milk, or milk with a very low bacterial content, therefore m the wholesale production of milk such results are still more difficult, and m fact impossible. The milk, immediately after leaving the milk canal, becomes contaminated by bacteria which have colonized there. Among the bacteria which may be found Reduction of Bacterial Content. 155 in the milk from animals free from udder affections, and wliicli has been drawn under aseptic conditions, the groups of staphy- lococci, colon bacteria. Bacillus snhtilis and B. mesenieyicus should be especially mentioned. Seibold also demonstrated acid-fast rods. Rullmann and Trommsdorff found no representative of the colon group, but they isolated staphylococci, a few representa- tives of spore-bearing species, and especially the anthracoides (Tuyeoides) species. In ordinary milk production there also come into consider- ation an army of air and stable bacteria, which adhere to the food, manure and litter, as well as those which vegetate, as saprophytes, on the skin of cattle, especially on the skin of the teats, and on the hands of the milker, besides those groups of bacteria which colonize with special predilection on milking utensils and in the cans. The number and kind of bacteria found by the different authors vary to a considerable extent, depending upon the degree of cleanliness user c. e. In dirty milk cans 215,400 to S0(;,n20 bacteria per c. e. Russell, in using sterile milk vessels, found 1(15 baeteria per c. c. in fi-eshly drawn milk, while in case of only (H ilinary cleansiiiii- there were 4,()25 bacteria per c. c. in such freshly procured milk. Grotenfeld counted in the milk from well-kept animals, in clean stables, only 106 bacteria as compared with 670,000 per c. c. in milk from dirty stables. The kind of milk can also has an influence. Backhaus con- siders enamel cans as the best; tin vessels Avere found to be almost as good, while milk vessels constructed of wood were unsatisfactory. The work of Koning shows the influence of the bacterial flora of the air on the bacterial content of the milk. The author counted 500,000 to 700,000 bacteria in the stable air. whereas the outside air contained only 90,000 bacteria. He found that the volume of air between the cows was especially rich in bacteria. Milk which is procured in the pasture contains fewer bacteria than stable milk. If it is customary to change the straw and also feed shortly lief(ir(> or during the milking time, these factors tend greatly to increas(> the bacterial content of the milk. If the milk is subjected to the so-called "improving methods" of the most varied kinds, and has to be transported for long dis- X56 Bacteria in Market Milk. tances, it is obvious that when it finally reaches the consumer it must contain tremendous numbers of microbes of various kinds. The author counted in the market milk of Munich from 13,000 upwards to several millions of bacteria per c. c. Milk offers to most bacteria which may contaminate it a splendid culture medium, their multiplication in it depending on the character of the container (cans, flat or open bowls), temperature and subsequent treatment. Freudenreich, B. Meyer, Cnopf and others conducted experi- ments on the influence of cooling on the number of bacteria, and established definite proof for the statement made in practice that immediate cooling constitutes the best preserving agent for milk. According to Cnopf the multiplication at deg. C. was re- markably low, at 12.5 deg. it was 4 to 935 times greater, and at 35 deg. 2,200 to 3,800 times greater than at deg. C. Freudenreich proved that in milk which at the beginning of experiments contained 10,000 (accurately 9,300) bacteria, they scarcely multiplied when kept for three hours at 15 deg., whereas at 25 deg. they doubled, and at 35 deg. they tripled in quantity. After six hours at 15 deg. they numl)ered 2.7 times, at 25 deg. 18.5 times, at 35 deg. about 1,300 times more than the original number, while after nine hours the number when kept at 15 deg. was 5 times, at 25 deg. 108 times, at 35 deg. 3,800 times as numerous as in the original count ; and in 24 hours at — 15 deg. C. the count was 5,700,000, or 613 times 25 deg. C. the count was 50,000,000, or 5,380 times 35 deg. C. the count was 570,500,000, or 61,344 times The author desires at this place to comment especially on the slight, and somewhat problematical value of Tiacterial counts, not alone because the results of the different sowing and counting methods show such enormous differences, but because the entire systen> also depends on a supposition of the development of a colony from a single bacterium which was previously present, a premise which is open to very serious objections. If it is considered how many bacteria attach to tenaciously adhering threads (sarcina, streptococci) , and how many bacteria possess a tendency to proliferate in cultural combinations, and to remain together in the relatively sticky material of milk, then it becomes apparent that the counted bacterial number represents but a small part of the number of bacteria which are actually present in the milk. Of course in general the number of colonies developing on the plate represent a certain initial point for deducing whether and in what degree a bacterial growth has taken place in the milk, but it does not indicate more than the relative age of the milk, since fresh milk may also be rich in bacteria, and besides luxuriantly growing as well as slowly multiplying bacteria may be present in the milk. A better method for the establishment of the actual number of bacteria in milk is the one suggested by Skar, which consists of a direct count of the bacteria in a smear (see technique). Through plating a certain impression is obtained of the kind of bacteria occurring in the milk, and corresponding to the growth of the colonies and the morphology of the bacteria it is possible to draw certain conclusions as to the groups under which the bacteria that are present may probably be classified. Further deductions as to whether the microbes should be con- sidered pathogenic, and whether bacteria are present which confer Thermal Limits of Bacteria. 157 disease-producing properties to the milk through products of de- composition, splitting up of proteids, etc., can only be possible after an accurate determination of all properties which would allow the recognition of the colony as a certain species belonging to a large group. This determination of tlie representatives of a group is not simple, and requires study and continued experimental work of days and weeks relative to fermentation qualities, requirements of growth, pathogenic properties on test animals, ferment-like characteristics, etc These experiments are only of an optional value in practice on account of the easy decomposition of milk as a food substance. Nevertheless through continued experiments on these problems valuable data and results have been obtained increasing our knowledge of the spread of typhoid fever and the methods for combating this and other diseases. Therefore, it should be aimed to prevent the entrance into the milk of directly or indirectly injurious bacteria by procuring the milk in a clean and careful manner. Once such bacteria gain entrance into the milk and multiply, their recognition and isnla- tion are too difficult for the practical inspector of milk to consider. Milk hygiene can produce practical results only if it is inau- gurated at the place of production. The pathogenic bacteria of diseases of animals and man will not be considered here, and only brief consideration Avill lie given to the army of saprophytes which gain entrance to the milk from the air, straw, manure and the milk vessels. Although from the numerous possibilities of infection of milk a definite bacterial flora can hardly be ex])eeted, nevertheless, cm- responding with the nutritive material of the milk, and the methods employed in its storage and transportation, as well as the subse- quent treatment, conditions are created which are favorable to some varieties of bacteria, while for others they are less favorable or even harmful. Through the growth of a certain kind of liacteria the conditions may be changed in such a way that the require- ments of propagation for other groups are produced. Likewise through symbiosis conditions may be developed which are re- quired by certain species of bacteria, or under which certain species may be destroycMl, whereas without s^nnbiosis probably neither of the species could exist, since they are dependent upon each other. The growth of certain species is therefore dependent on numerous influences. According to the thermal limits in which bacteria can live, the species may be separated into those which thrive at deg. C. (up to 1.1-20 deg.) : psychrophile; those which thrive at 10-1.5-40 deg.: mesophiles; and finally into thermophiles, whose thermal optimum ranges between 40 to 70 deg. C, or even higher. The species of psychrophile propagate even in well cooled milk and at low temperature, and at times change its taste. Eef- erence should be made here to the Bacillus lacfis saponacei and the Bacillus sapnlacficum, which give a soapy taste to the milk. This defect of flavor is principally observed in cool weather, and at the beginning or end of the winter. 158 Bacteria in Market Milk. Subtilis varieties, myeoid varieties, vinegar bacteria, yeasts, Penicillium glaucum, mucor varieties and aspergilli also grow from to 8 deg. C, as do soil bacteria, fluorescence varieties and bacilli which split np proteids (bitter taste of milk). According to Kniisel, psychrophile bacteria may be demonstrated in sterilized milk, while Bischoff found them in the market milk of Leipsic. Bischoff found that in milk which had been cooled to about deg. C, the bacterial number gradually diminished from the third to the seventh day ; it then multiplied rapidly, without showing a considerable increase in the degree of acidity. A bacterial rennet formed, however, and the milk coagulated on boiling. This appeared as early as the fourth to seventh day, when the milk was kept between 6 and 8 deg. C. Frozen milk on the other hand keeps for a remarkably long time. Kniisel found peptonizing bacteria in sterilized market milk which had been kept at 8 deg. C. ; as a result of their growth the milk had the appearance of soapy water, and possessed a bitter taste. Therefore, all milk cannot be protected from spoiling by being kept cool. The milk must be procured at the start with as small a number of bacteria as possible. The opposite of these psychrophile species are the thermo- philes, which may be actually isolated from the army of accom- panying bacteria by a high degree of heat. They continue to grow even in temperatures of 70 deg. C, and over (Zettnow), a tem- perature at which most of the vegetative bacteria and to some extent also spores of the mesophiles and psychrophiles are de- stroyed. Such bacteria were found not only in hot springs by Certes, Garrigon, Karlinski, Teich, Tsiklinsky, but also in river water (Miquel, Tieghem, F. Cohn, MacFadyan and Blaxall, Michaelis and others) ; finally they were found almost everywhere by Globig, and in the intestinal content of animals, feces, manure, liquid manure, in the soil and upon fodder by Rabinowitsch. The thermophile species are not directly pathogenic. This group, however, contains several toxin producers, and peptonizers of milk. Sporulating bacteria which form spores that resist a heat of 100 dog. C. and over should not be confused with the thermophiles. (Peptonizing species, as mycoides, anthracoides, subtilis, mesen- tericus and the butyric acid bacilli). Between the psychrophiles and the thermophile bacteria lie the large army of mesophiles, to which belong most of the ordinary species of bacteria found in market milk. Corresponding to their requirements for oxygen they are divided into obligatory aerobes, which propagate only in the presence of oxygen, facultative anaerobes, which can vegetate without oxygen, and obligatory anaerobes, which can grow only in the absence of oxygen. They may also be divided, according to the substances which they attack, into those which split sugar, proteids and fats, or, according to the products which they form during their growth in certain media, into acid producers (lactic acid producers, butyric acid producers, etc.), or into alkaligenic species and gas producers, Period of Incubation. 159 alcohol produfors, bacteria Avith rennet-like action, pigment pro- ducers, slimc-torminn' bacteria, etc. The varieties of bacteria which are found in milk under general conditions of production, even when conducted under special provisions for obtaining- clean milk with unusual precau- tionary measures (provided that the milk originates from healthy animals and is drawn by healthy milkers), are of special interest to the milk hygienist. These bacteria split sugar and proteids, and attack fat. Ac- cording to Fliiiige, they are separated into : 1. Aerobic lactic acid bacteria, which cause spontaneous souring and do not form spores; '2. The anaerohic butyric acid bacilli, and .'1. The aerobic peptonizing bacteria, with remarkably resistant spores. These baeteiia, however, do not propagate uniformly well in milk, but tliey are subject to influences of the nieilium, which really constitutes an elective culture medium for some of the sjxM'ies, whereas it is destructive for others. The time during which no increase of bacteria can be noted in milk is known as the period of incubation (Soxhlet). In fact there may be not only no multi- plication of bacteria in the milk, but under certain conditions dur- ing tb(> beginning of tlie incubation there may even lie a diminu- tion of the bacterial number which is first found; the bacteria present in tlu' milk are subject to the injurious influences of the animal secretion; the milk is in the germicidal staue (Koning). Fokkcr in 1S90 was thp first to assert that raw milk (ho iised for his experiments goat's milk) must have Kermii'iilal proprrties. lie jiroved that raw milk when inocnlateil with lactic acid bacteria resists spoiling for a longer period than wa-- flic la-ic with milk that had been boiled. Prior to his investigations however Wolffliiitrcl and Riedel found in issii that cholera vibrios readily nuiltiply in boiled or sterilized milk, whereas in raw milk their ;;r(jwth is rapidly checked. As a result of tliese findiiius the question as to whether milk possesses germicidal properties became the sidi,iect of dis)nite. While Frendciireicdi, Hesse, I^ark, Cozi-olino, Conn, Schenk, Behriny-, Knllmann and Trommsilorff, Rosenau and McCoy, Sasscnhagen and Bab claim that milk |iosses*es inhibitine, or even destructive properties for bacteria, Richet, Hiieppe, Heini, Friedrich, Kitasato, Utfelmann, Weigiriann and Zirn, Basenan, Schrank, Schottelius, JForo, Heinemann, Rubinstein, Storking, Somnierfeld, Klimmer, Knox and Sdiorer. and Knntze express; their belief against this power in the sense of the bactericidal action of blood serum, and think that the germicidal properties exist only towards certain species of bacteria. They also believe that the composition of the milk creates favorable conditions for the jiropagation of some of the bacteria, while for others this is not the case, just as with elective media, some of the less favored species become injured or destroyed by the multiplication of lactic acid bacteria and their products. The presence of specific germicidal substances (alexins, ambo- eejitois, leucins) in special kinds of milk, such as colostral and mastitis milk, has been proven by the work of Bauer, Sassenhagen, Kullmann and Trommsdorif, whereas the question of the occur- rence of these in normal milk has not yet been sufficiently demon- stratecl. although the fact of a diminution of bacteria in freshly drawn nonnal milk has been established by our methods of counting. 160 Bacteria in Market Milk. In order to furnish a few examples, several experimental results will be cited from the work of Grrimmer. Koning found in various samples of freshly drawn milk the following numbers of bacteria per c. c. : Milk : Colostrum : 1. 2. 143,000 142,000 immediately 107,000 after 6 hours 96,000 after 12 hours after 18 hours 120,000 after 24 hours after 30 hours 145,000 after 36 hours after 42 hours 490,000 3. 18,510 16,000 2. 82,900 76,400 155,000 470,000 1. 77,000 71,000 74,000 14,700 56,000 13,200 115,000 13,800 115,000 2,050,000 106,000 596,000 800,000 The slight diminution of the bacterial content of this experi- mental series could of course not be attributed to the existence of a specific germicidal action, but rather to errors in our methods, or to the elective action of media, since the differences are relatively slight. The results are more apparent in the tables of Eullmann and Trommsdorff : Keeping at room temperature : Teat Milking Imme- diately 1 hour 2 brs. 3 hrs. 4 hrs. 5 hrs. 19 hrs. 43 hrs. fr. rgt. beginning 2,400 2,100 2,300 1,900 2,100 2,500 2,100 1,200,000 middle 1,400 900 1,300 1,600 1,800 1,700 1,300 1,400,000 end 700 800 600 900 700 1,100 700 500,000 fr. 1ft. beginning 12,000 900 9,000 7,000 7,000 9,000 6,000 1,000,000 middle 16,000 14,000 1,800 1,400 1,100 1,600 1,600 450,000 end s.ono 1,000 2,400 2,400 3,000 2,700 2,200 1,100,000 h(l. rgt. beginning 200,000 118,000 118,000 10,700 98,000 71,000 33,000 420,000 middle .35,000 56,000 37,000 23,000 38,000 28,000 17,000 250,000 end 13,000 11,000 10,000 5,000 2,600 2,400 900 1,400,000 hfl. 1ft. beginning 7,000 4,400 4,600 7,200 5,400 5,600 7,200 20,000,000 middle 60 400 160 240 180 240 160 10,000 end 3,400 .3,000 3,600 2,600 5,000 2,200 2,100 230,000 In special samples with small bacteria] count the comparison was still more striking: Cow No Teat At room Imme- After After After temperature diately one day two days three days 8 fr. rgt. beginning 160 40 16,000 2,000,000 middle 80 40 18,000 16,000,000 end 40 80 17,000,000 20,000,000 fr. 1ft. beginning 11,000 9,000 8,000 40,000 middle 1,700 720 40 1,200 end 1,300 600 800 18,000 hd. rgt. beginning 120 400 2,500,000 5,000,000 middle 40 400 18,000,000 60,000 end 180 160 64,000 5,000,000 hd. 1ft. beginning 200 40 78,000 5,000,000 middle 80 500 300,000 6,500,000 end 240 80 50,000 2,500,000 9 f r. rgt. 600 360 2,-500,000 25,000,000 fr. 1ft. 40 SO 43,000 4,000,000 hd. rgt 450 500 2,.500,000 25,000,000 hd. 1ft. 40 240 9,000,000 innumerable Gennieidal Properties. ] 61 Trommsdorff and Eullmann conclude from these and other experiments that the bacterial content of milk does not increase at room temperature in the first period following the milking. ' ' On the contrary in some of the samples inside of the first .5 to 7 hours a pronounced diminution of the bacterial number was observed, which was still more pronounced in the following period so that in a great number of cases the bacterial number, after 1, 2, and even 3, and in one case even after 5 days, was found lower than directly after the milking. Where there occurred no diminution in bacteria the bacterial content remained the same as that found after the milking, during 1 to 3 days." ]\rilk Avhich lias been contaminated witli nnmerons bacteria in the earliest periods after milking (dirty milking, filthy ves- sels), shows only to a very slight extent the germicidal phase. At .">7 deg. C. the germicidal substances act more rapidly, but the dtira- tion of the germicidal phase is shortened (Koning, EuUmann and Trommsdorff). Heating the milk to over 70 deg. C. destroys its germicidal properties. Bauer and Sassenhagen established the absence of complement in ripe milk which gives the impression that in ripe milk the action is elective in the sense that the contained substances constitute food for one microbe and poison for another. Of course, it has ) een establii-hed for even ordinary kinds of bouillon that, depending on their conipositioii, tlio growth of certain bacterial species upon them has been checkeil for a time (Baseuau). The lecithin contents of raw milk must not be left out of consideration; in certain concentrations lecithin exerts a strong inhibitory action on bacterial growth. Finally the diminution of the bacterial content may be only apparent, as the bacteria may multiply through their sticking together in agglutinateil masses, thereliy simulating a diminution, a view which is supported also by Bali for colo^tral milk. After the germicidal action of the milk has worn off the various phases of decomposition of milk set in, licginiiing sooner or later, depending on the original contamination of the milk. Koning distinguishes seven such phases. The fight of the microbes, their harmonious, or ai^ain anta- gonistic relation to each other, results in a predominance of cer- tain species of bacteria in the various phases. First (second iihase according to Koning, the first being the germicidal) the proteolytes split up the proteid bodies of the milk, and thereby prepare the soil for the acid producers, which domi- nate the further decomposing phase (third phase according to Koning) ; the milk coagulates. In the fourth phase the alkali pro- ducers partly neutralize the acid again liy further splitting up the allinmoses of the acid milk with the formation of ammonia. Pep- tonized casein is also attacked. The principal representative of this decomposing phase is the Bacillus fcrcalis all-alifjenes (Gram negative, no gas formation, no indol, no spores, colors litmus milk l)lue). Through neutralization of the lactic acid, certain lactic acid bacteria. Bacillus acidi paralacfici, Bacillus acidi laroJactici and MicrDCDccus acidi paralacfici liqucfaciois. again regain predomi- nance (fifth phase). Kp to this stage the higher fungi have played a subordinate part, altliough they may have multiplied ; now they appear in great massi'<. The degree of acidity does not hinder their growth. The 11 IQO Bacteria in Market IMilk Oidium lactis participates principally in the sixth phase of decom- position, although other varieties of moulds, penieillia, and mucors may also play a part. The degree of acidity being diminished by the oidium, bacteria of the fifth phase again commence to multiply, until the seventh phase is inaugurated through the growth of the anaerobic butyric acid bacilli. According to Koning this phase is reached at room temperature on about the eighth day. Grasberger and Schattenfroh designate ^the principal representative of this bacterial group, the Bacillus saccliaroliutyricus immohilis Hquefaciens, a bacillus which is large, thicii and stubby, stains after Gram, and forms spores which are located either centrally or at the end of the bacillus. According to Burri the bacillus may be most readily isolated by boiling the milk for several minutes, and allowing it to ferment at 37 deg. C. Besides this butyric acid ba'cillus, other motile forms or bacteria related to the first group may be found. The seventh phase finally passes into the eighth, in which the milk changes into a stinking "putrid fluid, in which the decomposi- tion of the food material is completed by the proteus, subtilis. Bacillus fliwrescens, and Bacillus mesentericus, besides mould fungi. Of these phases of decomposition of milk the first three, espe- cially the second and possibly the beginning of the third phase, are the most important. In these two phases the proteolytes and the rennet formers are the first to multiply, causing a partly visible precipitation of the casein, but subsequently again dissolving it ; further, the precipi- tated protein is immediately partly dissolved when the dissolving tryptic ferment is present to excess. Weigmann collects these bacteria under the name of casease bacteria. On account of their properties of producing peptones from proteid bodies they are called peptonizing bacteria. Most of them liquefy gelatin. The group of casease bacteria includes a great number of forms of bacteria, for instance : staphylococci, small spherical bacteria which occur ubiquitously and in smears from cultures appear as grape-like conglomerates. They stain by Gram's method. They grow from deg. to about 40 deg. C, and frequently form at 15 to 20 deg. and over, yellowish orange, or lemon-yellow colored colonies. At a low temperature the casease enzymes are especially active. In gelatin stab cultures staphylococci first develop a nail-like growth; the liquefied gelatin may then dry and at the point of the stab a bell-shaped air vesicle forms, or the liquefaction may progress rapidly and a cloudy layer of liquid with a sediment of staphylococci stands above the solid gelatin. In gelatin plates the small round colony drops into a cup-shaped depression which also results from the drying of the liquefied gelatin. Besides the formation of albumose and peptones the milk sugar is split up; Lohnis therefore classifies these organisms with the lactic acid bacteria. The growth of sarcina, which collect into two, four or eight members, etc., is similar, thereby forming bacterial clumps of certain forms. They are also Gram-positive. On account of their occurrence even in milk drawn in the most cleanly manner, their presence in the udder was accepted, and as a matter of fact pathogenic organisms do occur in the group of staphylococci, which produce inflammations of the udder. Ordinarily however, they only inhabit the milk duct. The putrefactive representatives of the proteus varieties should be classified among the non-spore bearing casease bacteria. They manifest many forms of growth, and include the following representatives: Proteus eopfii, ^enl^eri, vulgaris, mirabilis, and fliwrescens. Putrefactive Bacteria. 163 They are rod-shapeil liacteria, motile, non-spore bearing, and Gram-negative. The forms of colonies and characteristicK are quite variable, sometimes showing root-like extensions, and at other times branching outshoots. The most important spore-forming proteolytes originate from forage, hay, stable dust and the stalile air, and are collected, under the name of potato bacilli, hay bacilli and root bacilli. They are small rods up to the size of the anthrax bacillus, ivith central or terminal sjiores, and are rot('id sulistanees is carried out, if possible, with the production of end products such as h'ucin, tyrosin, anuiuniia, car- bonic acid, indol, skatol, methyhncrkaptan, sulpiuireted hydroiicii, toxic toxallnunins, and ptomaines. For the judgment of milk Avhich is considerably coiitaminatcMl ^vith bacteria from litter and forage the increased presciiec nf sue!) bacteria is of special importance, since most ot them form sjiores which are not always destroyed at the temperature of KM) dcg. ('. and higher. The Bacillus prodigiosuf^. Bacillus fluorcscois Ii(iurf(iciriis, Bacillus aiin/lobacfcr, and Bacillus putrificus Bienstock, may also split up proteins. Their ]iroducts vary. The bacterial substances which dissolve proteins and split them up, exert their action es]iecially in neutral and alkaline ma- tei'ial, and they are therefore hindered in their action by the pro- ducts of the third phase, the second decomposing phase. The lactic acid producers, however, proliferate only after the necessary requirements for their propagation have been created by the activity of the peptonizing bacteria. Through the activity of the lactic acid bacteria the milk sugar and other varieties of sugar are fermented to dextro-rotary (ro- tates plane of polarization to right) lactic acid, inactive lactic acid, and levn-rotary (rotates plane of polarization to left) lactic acid, depending on the species of bacteria or the conditions under which the special species ])r('vail. The splitting of lactose C JI^.^O,, is accomplished by an inverting bacterial enzyme, the lact;i-c, through the intrnductiou of water whereby it is converted into L'(',dl,,0, known as l>-gluc(ise and D-galactose, which by further splitting break up into 4C,I1„0,. 164 Bacteria in l\Iarket Milk. The lactic acid yield, liowever, corresponds even in the extreme cases only to about 98% of the contained milk sugar, as in the mean- time, depending on the variety of the lactic acid prodiicers, the lactic acid itself is again broken up into simpler acids, acetic acid, valerianic acid, succinic acid, and carbonic acid ; alcohol, aldehyde and possibly hydrogen result besides the lactic acid. In spontaneously coagulated milk mostly inactive lactic acid is found, or a mixture of inactive and dextro-rotary lactic acid ; but only in exceptional cases is pure dextro-rotary lactic acid found (Gunther and Tierfelder). Kozai mostly found only the dextro- rotary polarizing form. The lactic acid bacteria may also be considered as ubiquitous micro-organisms ; they have been found in straw, hay, fodder, dust, feces and in the air. Proliferating in milk they soon adapt them- selves to the nutritive medium which at first is not quite suitable for their propagation, and finally they form standard varieties for which the milk is especially adapted. Through continued growing a weakening of the acid forming qualities may develop, and the coagulation of the milk may not take place in spite of their growth, the bacteria having become "milk tired." Under these conditions they may show other properties, the bacteria rendering the milk slimy instead of sour, which is known to be the case with some of the lactic acid streptococci. The specific lactic acid bacteria are aerobes, or facultative anaerobes. Lohnis separates the specific lactic acid bacteria into four col- lective groups : 1. Streptococci. 2. Plump short rods. 3. Slender, long, lactic acid bacilli. 4. Micrococci and staphylococci. The most frequent of these are the representatives of the streptococcus group. Arranged into wreath-like, shorter or longer bodies, the individual members are characterized hj coccus or oval- shaped bodies. On artificial media they frequently manifest vacuo- lar degenerative forms which change the individual microbes to the size of bacilli. Frequently pure diplococcic forms may be found which at their ends are mostly pointed in a lancet shape." Strepto- cocci grown in milk are composed of individual members mostly in the shape of a figure "8" which lie with their long axis in the direction of the chain proving them to be streptococei'that entered the milk after its secretion as compared Avith the forms from the udder. Some of the representatives form capsules but only under special cultural conditions, as for instance in blood medium, while in other media capsule formation appears to be a constant charac- teristic and occurs especially in old milk cultures. Most of the streptococci are Gram-positive. They possess no motility and form no spores. On solifl media the colonies usually remain delicate and small ; in fluid media streptococci. 165 the growth takes place either with general clouding, or with the formation of flakes and tufts and the bouillon then remains clear. The optimum temperature of the growth lies between 1ci>ccus hol- lauilirus, Bnclcrium lactis loii/ii, "sticky milk" producers, Micro- coccus iiiu<'ila//inosus, Bdclcriuni lad is aciili. li. Those which in culture forui vine or tongue-like shoots. 7. Those which liquefy gelatine. It is well known that the cultural (diaracteristii'S of the strei'tococei luny readily chanue: a strong acid forming variety may lose this characteristic by long cultivation in milk, and may bei'Ome a slime proilucing variety, so that the distinguishing feature is not absolute. There are transi- tory forms between one and the other ty]ie, and oue type at some time may change into another type by chanL;iiiu its iliaiacleri'-tics. Some varieties also belong to those sti'eptococci (collective name streptococcus or Baclcrinm lactis acidi Leichniann), which produce volatile substances and alcohol from milk sugar and which at the moment of their development unite into a fragrant substance, ■.i so-called fruit e^ter, wdiich reminds one of the odor of a certain fruit or fruits; other representatives of this variety produce other substances with odor ami taste, which may 1 e described as straw-like, sorrel-like and especially malt -like. The author never succeeded in producing striking odoriferous substances in sterile milk with the streptococci cultures at his command. He, however, does not wish to refute from his few experiments with aliout 20 strains froui various provinces, the possibility of the production of special odoriferous sulistauces by the Streptococcus lacticus. Umler certain coiulitioii.-;^ tremendous quantities of streptococci may occur in market milk from cows wliieli are affected with strep- tococcic mastitis. Sjn'cial reference lias been made in the chapter on affections of the udder, regarding the similarity of these patho- V. ' \'/ — ^— _^_— - ,_r' ■.;-,-N ;-■-- - "i*ri' . -— . ;'" -74% '.<'' '*'* \ '•tl.' •*> • ■".'**' ■!>' '■ ■ - ■'- ** :■'- \ Hr: .•>•. v r-*^ " •^ ■■■'-■■'^ 4 ^ i \ S _ • V. r.-'-" ■#■ •f^-'l^ ^ } '"•: .-. MJ<^ rl- '' ■■ ~— ,_ ..■•■.■P"\. 1- ,.^-- — -* — * .,'» ^ «-tic> : f). Those producinii- slime; (I. Those growing in tendril-shaped colonies. The bacteria of this third group are almost invariably non- motile, and s]ioi-eless, mostly without capsules. They are Gram- ])ositive. The fermentation of sugar varies. In milk they mostly form levo-rotary lactic acid, while the other two varieties are rarely ])rodnced. Some peptonize ]iroteids ; their growth is favored more bv aerobic than bv anaerobic 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 prolific 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 delbriicJii 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 ac- 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 staphylococci 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 mimber 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 anaerobic fermentation of grape sugar, produces ethyl alcohol, formic acid, butyric acid and lactic aciil ; cholera vibrios and related organisms form lactic acid; for instance the vibrio of Asiatic cholera, the Vibrio proteus (Pinkler and Prior), Vibrio massauah, vihrio danubinis and others form levo-rotary lactic acid, the vibrio of Deneke forms dextro-rotary and Vibrio berolinensis produces an inactive lactic acid. The formation of these lactic acids, however, does not depend on the bacillus alone. The Old i urn lacfis, 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 fiora, the presence of which under certain conditions may be desirable since by their multiplication the vegetation of the harmful peptonizing bacteria andof the producers of butyric acid is inhibited. _ With this we leave the most important varieties of bacteria which are responsil)le for the normal spoiling of milk, and will briefly discuss those varieties of microbes belo'nging 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. Butyric Acid Bacilli. 169 The specific butyric acid bacilli are obligatory anaerobic or facultatively anaerobic, 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 Isinds of sugars, as well as toward the formed by-products, as butyl alcohol, isobutyl alcohol, f'liniiic acid, acetic acid, propionic acid, valerianic acid, carbonic acid, hydrogen, etc. The obligatory butyric acid producers are rods, chains or threads, with either a plump or a slender form; tlicy possess oval or roundish polar or central spores. The bacteria Fi- 26. Blackleg bni-illi. 1 v i2iio. (.Vfter Frieilberger & Froliner.) frequently form so-called Clostridium forms, and csiiccially in starrhniiitaininu media tliey 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 patholoi;ists as producers of blackleg, gaseous phlegmons, malignant edema, bradsot, botulism, and tetanus. These baciUi at times are capable t)t' energetically forming butyric acid, and at other times less in- tensively; at the same time peptonizing ferments (tryptic) are fiirmed, which become active in the absence of acid. (lenerallv motile and non-motile forms of butyric acid bacilli are distinguisluMl in milk. The latter form of the granular Bacillus sdrchardhutijricus is considered by Grasberger and Schattenfroh as a developing form of the motile, spore-fonning variety which takt's up granulose, forms toxins, and attacks lactic acid._ According to their ^iroperties 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 Schattenfroh), and the bacillus of gaseous phlegmons (Frankel). The others are producers of putrefaction and split up the proteids into 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- cvm (Huss), through the growth of which the milk acquires a rancid taste. The Bacillus fluorescens, Bacillus prudir/iosus 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 (chronic suppurations). Some varieties of l)acteria classified by Lohnis as lacto-bacilli, as for instance a microbe isolated by Chattei'jee from "Dadhi," (Indian sour milk) Strepfotlirix daclhi 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 alcoholic 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 Oidium lactis, under which name are collected all mycelial forms, whose radiating mycelia carry hyphse, that break up into small, rectangular, cylin- drical members, the so-called oidia, which in proper media again grow out into a mycelium. The growth of the oidium varieties 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 eloselv related Buttermilk. 171 moniliar varieties wliieli at times urow like the oidia witli a typical mycelium, at other times it is a sporulating fmigus (Mon. raiin- hil'is; candicans, etc.) ; also varieties of mycoderma, which always iiuiltiply in a longitudinal direction, by the protrusion of daughter cells which continuously bud out new daughter cells and these con- tinue to groAv in tlie already established direction. In the pre])aration of certain fermented forms of milk which arc frequently desired in certain sour milk preparations, the sporu- lating fungi which multiply in all directions of space through sporulations are of importance. Througli 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 saeeliaromyces varieties, which form endospores and torula varieties, whose daui;htei' eells no longer se]iarate in nil directions but ;irranging themselves into rows form mostly sjiheri- cal shaped or sausage-slia])e(l buds, and have no endosi)oies. Milk Preparations, Buttermilk, Etc., Produced By Special Fermentation. jMany varieties of foreign buliermilk or sour milk have recent- ly become known in this couiitiy. Esjiecial dietetic valn(^ is attri- btited to tliem ; as to whether they possess advantai^cs over otir dwn buttermilk nr not is not vet known. The author beliexcs that our native buttci'milk possesses the same advantai;cs provided it is ])repareeeoining liiihter in weight through alisorption of carbonic acid they rise to the sur- face of the milk, whereas kernels in which one of the varidies of microlies for some reason or other became destroyed and di'i^cner- ated remain on the bottom of the vc^ssel. If the dcL^cuerated 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 liy 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 bonis at 14 to 18 deg. C, with frequent shaking, then a primary or mother Kefir is obtained, from which through further fermentation in eorked bottles the Kefir may be prepared ready for use. The "millets of the prophet," the Kefir kernels, are strained throudi a sieve, and the homogeneous fenuented milk is filled into l)ottles, or from the strained fluid a considerable quantity is poured into a l>ott]e, to which boiled milk cooled to about 20 deg. C. is added. The bottle is then closed and allowed to continue to fer- nu'ut for from 24 to 28 hours, at from 12-15 deg. 0._ In this ])rocess the casein and serum separate but may be readily homo- -ciiizi'd 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 Eussia, Siberia, and Central Asia, Avhich 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, alcohol and carbonic acid fermentations are the principal processes. After long fermentation Kumys contains up to 2 ^^ of alcohol and 1% or more carbonic acid. Bacteriologically Kumys is of similar composition to Kefir containing yeasts, lactic acid, streptococci, and the Bacillus humys (Sehipin), which is a facultative anaerobic 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 l€!8,st d.Gsirs,l)lG, 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 Grioddu 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. In 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 (Pinguicula 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 (Weig-mann). 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 biolog- 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. TabU IV. /f ( i il i^-^ !/ i) I \ ^Afri\ Butyric aii(] bacilli in bailed milk, kept for two days at 37 °C 1X1200. \ Film of Ynghurt. Bacillus bulgariciis and la: iL-'nu. r, nst, MHU HmjU'i' Bitter Milk. .10 Porcelain vessels and bottles made from glass free of lead are most suitable for the preparation of buttermilk, since the butter- milk may extract lead from enameled earthenware and from pots \vli()S(' g•lazill^■ contains lead in its composition. According to Chlopin 0.84 mg. of lead was extracted from 100 gm. lactobacillin-buttermilk; in a second portion (300 gm. butter- milk) which was five days old, the amount reached 7 . S6 mg. Brlick- 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 designat(Ml as normal processes, or again others appear wliich are less frequently observed, oceni- ring only under special conditions and therefore are known as milk defects. The modification, as has l)een seen, may be even desirable, as for instance in cream souring and cream ripening for butter making, or in the preparaticm of Kefir, Yoghtirt, and linttermilk, or it may be undesirable and injurious, spoiling tlie milk, and having a disturbing influence on milk utilization, espe- cially in its use for drinking purposes. Among the changes in milk there are tliose which appear fre- (|nently, and others which are very rare. Under conditions which favor propagation of peptonizing bacteria (staphylococci, sareina, anthracoides, mycoides, mesen- tericus varieties, fluorescens, pyocyaneus, etc.), 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 casinn, and the milk coagulates without turning sour. It is "sweet-coagulating." By the action of peptonizing micrococci, which in part are psychrophilic the development of a 1)itter taste may occur in thoroug-lily cooled, and even in excessive- Iv 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- gels 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 ])otatoes, mouldv or spoiled hay, straw, etc. It may however be accepted that the development of a bitter taste in milk usually 176 Defects of Milk. results from its contamination witli varieties of bacteria vegetating on food substances, whicti enter into tlie 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. Eepresentatives of the colon-aerogenes 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 Eitland 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 anaerobic and facultative anaerobic 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 marshj^ 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 saponacei (Weig- mann) and the Bacillus sapolacficum (Eichholz), produces a soapj^ condition of the milk. The milk attains a sharp, rancid, soap-like taste, and when cold it reminds one of valei'ian ; 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- pliilic, originating from the feed and straw. The Bacillus lacticus sapnnacci grows Avell at room tempera- ture, liquefies gelatin, and produces a slight yellowish shimmering coloring matter; the growth is aerobic. The Bacferimn sapolacti- Blue Milk. 177 c It 1)1 .urows 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 individual 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 imiform 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 ndder of this cow was diseased). The same author mentions another ease which occurred on an estate in northern Germany. In that instance the milk of the Montavania cows in the stable was constantly ranidd, 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 ^[on- tavania animals which favoied the propagation of the Baclcrinm Upuhiticnm 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. Tt has also been proved that other chain;os in milk may per- sistently occur in the secretion of certain individuals so that it appears as if the causative agents of the chaiiucs in the milk may at times exist as saprophytes in the cistern ( vSehnltze), c Observed, which cause a glassy, transparent thickening of the wrinkled yellowish-white velvety layer of the oiclinm covering, or they penetrate into the dej^th of the jelly-like layer of the milk. Thus under certain conditions the BacUhis viohicciis. Bacter- ium jdiithhniw. Bacillus liridus, and Bacterium amethi/stiuus, a water oi'^anisiii, may appear in violet spots (Schroeder, Zopf, ]\Iaz(', Fliigge and others). (Ii-eeiiish-yellow sjtots and discoloration of the entire sour milk arc iiroduced by the Bacillus jhioresceus which varies greatly in its chai-aeteristics, at times liquefying gelatin, again only ilis- coloring it. It is a short rod with motility, but without spore fonnatiou. A red coloring matter is produced by the Bacillus erythro- ficnes Hueppe, which coagulates milk, but liquefies it later througli peptonization, cobiriug the wtjcy red. Accordiiii;- to Gruber a flagellated shoit rod, the Bacillus lac- ffiruhefacieus is supposed to ]»i'()(kice a slimy condition of milk with the formation of a red coloring matter. Otiier bacteria such as the Microciiccus cerasiuuni ( Kefei'stcin), the Sani)ia rosea, the Jlacillus prodiffinsus and others, form red s]iots. I^mI varieties of yeasts have also been found. The autlior demonstrated through the examination of a dirty and di'y milk i)ail that the layers of color which adliei-ed to dif- ferent parts somewhat like red \'aniis]i ccmsistcd of blue-ri'd yc^asts which liad grown on tlie dried milk residue. The aceunuilation of color was present in tlie yeast cells proper, which on examination showed a reddish transparency. Their attempted cultivatiou was unsuccessful. Tlie discoloratious 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 sunxautJius { Sdiroter), the Sarciiui lutea, the Sarciiia flaru, and lUuierium fulruui and others. Wild yeasts and moulds, which have been observed by tlie author may also cause a yellow coloration of s(Mir milk. The Bacillus funreseens, may at times caus(^ a yellowisli-nreeu discoloration. Other baeteria again show tlie action of their vegetation by the develoinnent of a tenacious slimy consistency of the milk. Strains and varieties of the peptonizing bacteria in which acid for- iimtion is dissi)iated and the peptonizing action of which retracts against the ])roperties of producing rennet-like substances, may in a few hours caust^ 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. ]\rore frequently, especially by keeping the milk in a warm place, a chaniic of the milk to a slimy consistence may be observed. The action of llie slime-forming bacteria may appear in two fonns. ]80 Defects 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-Miihlheim), Micrococcus mu- cllaginosus from slimy cream (Eatz), and Streptococcus hurri from stringy whey. Slime is further known to be produced by the colon-aerogenes group (Emmerling, Schardinger), the Bacillus fiuilleheau, as well as the Bacillus lactoruhefaciens. Adametz, Duelaux, Gruber, Ward, Eckles, and Marshall have also isolated slime producers from milk, whej^, 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 tliereby 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: a-. lO Various Defects. 181 rji CI CI CO CO CO CO o I--. CI CO -fH CO T-i CI CO CD CI cr. CI CO CO CO CO p CO CO CI lO CO CO T— ( CO) CO CO CO CO CO CO L^ CO CI CI CO o CO CO -I- ^! — " CO cr. CO c CO CjI CO o* -*' o CI lO o CO CO CO CI C I cc CO C) p oi OI o cri CO CI CO CO CO I- !>; 00 00 CO en CI CO CO X 1~ X I - X p-^ br. , Co ^ X X — p; C K C X X --■^ (*.-* 182 Defects of Milk. At the same time it appears as thougli 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- cal relation to the measured average value of the atmospherio 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 less importance in tlie 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 sii])|)Orteil 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 jiasture 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 niffht at a temperature of 12 deg. ('. 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. It 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. Cniv^nlation Types. 1^3 Af'coi'cliiig to Wolff and AYeigmann the Bacferiion flitoresceus jiosscsscs the characteristic of producing by itself an ester-like (xlor, while together with the Bacterium mycoides and the Strep- tocdcciis IdcficKs it produces a disagreeable aroma, and finally with the Jj'dcfrriinii ijipf/aflieriinii, B. mycoides, and lactic acid luicilli it produces a cheesy odor. This of course renders the study of milk defects difficult, since a bacterium cultivated in pure culture may sliow an entirey different action than when present in milk in a mixed culture, and mixed culture experiments with the entire Hi)i-a 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 \\)v the manufacture of cheese. \ fermentation test is made from each delivei-y of milk, and after a certain time each sample is tested for odor, taste, and in i-ei;ard to its appearance and visi))le changes. According to Jensen tlie fermentation may be distinguished a> : 1. A fluid 1yi)e, 2. A jelly type, 3. A gaseous tyi)e, 4. A whey type, 5. A cheesy tyjie. It should ])e emphasized tlnit milk samples rich in Imeteria usually ])i-()duce a, good jellylike type, whereas in milk samples containing Few liacteria, whey fermentation frecjuently oeenrs. The jelly ty](e results in the i>rofuse presence of lactic acid formei's, which distend and tear the coaunlum by the action ol' ai'rogenes varieties and cheese bacteria, 'whose i;as ]irodnction fre- quently forces the coagidum upwards. The milk becomes whey when true saccharomyces varieties form gas at the moment of coagulation. At the same time sub-types may be distinguished, sucli as porous, granular and flaky. The cheesy fermentation type develoiis in the presence of an increased nmnber of rennet- ])roducing bacteria. These fenneutation tests of milk are important to ascertain if it is in satisfactory condition for cheese production. For the di'- termiuation of its fitness for drinking pur]ioses, however, these tests are of little importan(H\ since the questions relative to the value which these bact(n'ia possess in the nutrition of man, have ne\-er been satisfactorily answered. Bacterial Reductase, Bacterial Catalase and Lactic Acid Production. Among the characteristics of milk ))acteria, which are of especial intei-est are those which are utilized in the examination of milk, and which may have a disturbing effect in experiment- 184 Reductase, Catalase, Etc. conducted for the demonstration of original ferments because of the reactions which they cause. One characteristic is the reduc- ing property of some bacteria and their ability to split up H2O2 into water and molecular oxygen, corresponding to the action of catalase. The reducing action of bacteria as indicated by the presence of reductase, has been observed for a long time. Helmholtz in 1843 proved that putrefactive changes which could not be demonstrated by changes of odor could be proved by discoloration of litmus coloring matter. Subsequently this reducing action was confirmed by many authors to be the property of various anaerobic and aerobic organisms. Thus according to Gayon and Dupetit the anaerobes are capable of forming ammonia from nitrates, while the Bacillus prodigiosus, B. anthracis, Hpir. finkler and staphylococcus citreus form nitrites out of nitrates. Others again reduce sulphur to HjS (through "Hydro- genase")- As an agent for demonstrating the reductase processes some authors, for instance Spina, Cahen, and Wolff, use coloring substances which change into leueo-compounds, as a result of the reduction, but from renewed contact with the air they become re- oxydized, as for instance tincture of litmus, thionin, methylene blue, indigo blue, neutral red, etc. Others again use metallic salts to render the reduction directly visible (Scheur- !en and Klett, Gosio), for instance selenite and tellurite, whose sodium and potassium cornpounds confer upon the colonies a brick-red or grayish-black tinge, by the reduction or indirectly, the transpiring reductive action is shown through secondary reactions, for instance the formation of nitrites from nitrates, through the addition of iodine starch paste which becomes decolorized by the nitric acid. Methylene blue is used at the present time most extensively for the reductase test; that is, the solution recommended by Schardinger consisting of 5 parts of concentrated alcoholic methy- lene blue_ solution to 195 parts of water is best adapted for the examination of milk. The reducing qualities of various bacteria towards methylene blue vary. Thus Jensen established the reduction qualities" of a series of milk bacteria, and proved that varieties of colon, staphy- lococci, sarcina, and mould fungi, reduce rapidly, whereas acid streptococci do not decolorize the solution. The findings of Koning, who used cultures 24 hours old in his experiments, were the same. Arranged according to length of time, reductions take place as follows: Bacillus fluorescens nonliquefaciens, in 8 min. Bac. acidi lactici Hueppe, in 12 min. Bao. prodigiosus, in 10-15 min. Bac. fluorescens liquefaciens, in 13 min. Proteus zopfii, in ig juin. Bac. coli communis, in 17 min. Bac. suhtilis, in 3q min. Mesentericus, in 60 min. Milk bacteria I, in 80 min. Streptococci of lactic acid, Oidium lactis and 2 stable atmospheric bacteria, not in 90 min. Schardinger in 1302 stated that suspensions of the Bacillus acidi lacvolaclici decolorize in 3 minutes, the Bacillus gasoformans in 3 minutes, the Bacillus lactis pituiioxi in 30 minutes, the Bacillus coli in 15 to 20 minutes, etc. The ability to reduce methylene blue has also been found in anthrax and tubercle bacilli. In the experiments it was proved that although not all bacteria are capable of reducing methylene blue, the power of reduction in some is very strong, while in others it is diminished and in still others it is practically nil. Reduction properties appear to be characteristic of the Hvi mg Reducing Properties of ]\rilk. 185 bacterial cell, which do not pass into the filtered fluid (Schar- (liiiger, Spina, Cahen). From the above mentioned facts it is evident that milk which contains numerous bacteria has a strong reducing property. Through the works of Smidt, Miiller, and Schardinger it has been proved that as a rule the richer the milk is in bacteria the earlier the reduction of the aqueous methylene blue solution at 37 deg. will occur. Milk drawn under sterile conditions fails to reduce the methylene blue solution even after days (Eullmann). Miiller proved that freshly drawn and cleanly handled market milk re- quires 10, 12 or more hours for reduction (mixing 10 parts to 1 part of methylene blue solution), whereas fresh market milk during cold weather requires 6 to 9, and in warm weather only 1 to 2 hours for the decolorization. At the stage when bacteria begin to multi- ply, which is at the end of the incubation period, the time required for reduction amounts to from 1 to 2 hours. If sour milk or cow manure was added to fresh milk the time of reduction was hastened. He therefore proved that all factors which favorably influence bacterial growth hasten the reduction. Tn the author's first investigation he fonnd that 10 p. i-. of milk with alioiit 44,000 bacteria per c. c. failed to reduce one c. c. of methylene blue solution in six hours. AVith about 200,000 baotoria reduction took place in 4 to fi hrs. With about 500,000 bacteria reduction took place in ^.-'i lirs. With about 1,600,000 bacteria reduction took place in 2 hrs. With about 6,000,000 bacteria reduction took place in 7(i niin. With about 350,000,000 bacteria reduction took plai'C in 50 min. With about 800,000,000 bacteria reduction took place in IT min. Similar results were obtained by Jensen as follows: With about 264,000,000 bacteria reduction took place in 1 min. With about 80,000,000 bacteria reduction took plai'c in .! to 5 min. With about 50,000,000 bacteria reduction took place in 10 min. With about 7,000,000 to 11,000,000 bacteria reduction took place in 4ii to liii min. With about 3,000,000 bacteria reduction took place in 2"', hrs. With about 1,600,000 bacteria reduction took place in 7i'j hrs. With about 1,000,000 bacteria reduction took place in 6^'i hrs. With about 126,000 bacteria reduction took place in Oi'o hrs. Since the degree of acidity increases with the growth of bac- teria there exists a certain connection between the degree of acidity of the milk and the rapidity of reduction, and since the degree of acidity increases rapidly after incubation, a rapid reduction would be expected to follow a rapid increase in the degree of acidity. This is also proved by Jensen 's experiments. Milk which reduced in one minute had after 12 hours, at 2.1 deg. C, a degree of acidity of 30. Milk which reduced in — 5 min. after 12 hrs. at 25 deg. had an acidity of 19 S min. after 12 hrs. at 25 deg. had an acidity of 20 fi min. after 12 hrs. at 25 deg. had an acidity of 35 10 min. after 12 hrs. at 25 deg. had an acidity of 22 S min. after 12 hrs. at 25 deg. had an acidity of 18 7 min. after 12 hrs. at 25 deg. had an acidity of 28 1 hr. after 12 hrs. at 25 deg. had an acidity of 15 v. hr. after 12 hrs. at 25 deg. had an acidity of 25.5 l-'i hr. after 12 hrs. at 25 deg. had an acidity of 11-5 186 Reductase, Catalase, Etc. 2% hr. after 12 hrs. at 25 deg had an acidity of 15 ."■;4 hr. after 12 hrs. at 25 deg. had an acidity of 9 GVi hr. after 12 hrs. at 25 deg. had an acidity of 9 7 hr. after 12 hrs. at 25 deg. had an acidity of 10.5 6% hr. after 12 hrs. at 25 deg. had an acidity of ^ 7% hr. after 12 hrs. at 25 deg. had an acidity of 8 12i/i hr. after 12 hrs. at 25 deg. had an acidity of 7 8% hr. after 12 hrs. at 25 deg. had an acidity of 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 c. c. of milk: Degree of acidity After 24 hrs. Time required at delivery at 20 deg. for reduction Eeduction number 7.0 7.4 20 hrs. 6.2 8.fi 20 hrs. 6 10 20 hrs. 6 9 20 hrs. 4 7 10 20 hrs. 6 24 4 hrs. 2 0.4 26.5 8 hrs. 10 6,5 26 8 hrs. 6 6.2 24 8 hrs. 8 6.2 27 8 hrs. G 6.S 23 8 hrs. 4 6 14 8 hrs. 4 7,8 .".(1 6 hrs. 4 6.5 28 2 hrs. 2 7.2 :V2 Ihr. 2 (i 34 Ihr. 2 6.2 38 Ihr. 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, Avithout 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 inhil)its the reduction power — as a matter of fact the rapidity of reduction is again considerably increased by the addi- tion of sodium carbonate 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 tlio r(>action is retarded, but this may be overcome when through acid formation neutralization has taken place. Bacterial Catala^o. IS'/ Antis('])tios, such as boracic acid, salicylic acid and formalde- liydo, inliibit or destroy the reduction power of bacteria; the same result is obtaincMl by heating, which destroys the life of tlie vegetating- bacterial cells. :\nik which has be(^n 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 marke(l degree, may have a slow reducing power, as for instance soa]»y milk, pi'ovided this condition is not associated Avith exteiisi\-e bacterial contamination with other species of bacteria. .MtliDUgii llie ))acillus 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 vei\v slight bacterial growth has taken place, although the bactei-ial action is of tremendous importance. For the c()iii])]eteness of this cha])ter it should be mentionecl that milk very I'ich in bacteria, wiiich lias been sterilizeil by heat, I'educes also llie formalin methylene Ijlue solution as a result of the oi'igiiud bodies in milk, a proix'rty whidi has luithing to , which occurs in milk drawn imder sterile conditions (origiiuil ferments). Bacterial Catalase. Similar to the power jiossessed by body cells and ])ody juices, l)actei-ia have the ability ol' splitting gaseous oxygen from hydrogen ])eroxi(le solutions. This property may be observed in many bac- tei'ia, l)nt it should be mentioned that not all sjiecies of bacteria ))ossess it, and that certain bacteria have a specific power in this direction. Koning and .lensen made confirmatory statements to this elTect, having found that the acid streptococci of milk do not s])lit II, ( ),. The author's experinients conlirm this observation. Jensen nmde an es])ecially interesting observation, namely, that the bac- terial Hora in-esent in milk during the incubation period of souring usually jiossess strcnig catalytic propertic^s. Tlic following (lata are taken from a work of Koniiiu-, arranire.l aceonliiiL: to the I'atalirc lii;u]cs: S|>ei-ii's III' llactrria Catala'se test BeJuetase test />'. iiiiiilifiiii.'iiis "^ l'> minutes /;. jiri'tt IIS -'i;'/'' •"" 1-' minutes Milk lia.-tiTiiim 1 •'■"> "^n minutes /;. tli'iiri SCI lis lii/iii fiirii-iis ■"•' l-i minutes /;. nili riimminiis ■"■'■' 1 . minutes 7>. Iiii-t. aiiil. Iluepjie :^'- 1- minutes Stalili' air l.ai-teria 11 •'■l !'i' minutes /;. Ill, s, nil riru.i ■Ill '''" minutes /;. fliiiirtsii 111 noiiliqiief. -9 1' minutes 188 Reductase, Catalase, Etc. Stable air bacteria T 28 90 minutes B. suhtilis 17 40 minutes Milk bacteria II 15 90 minutes B. mycoides 11 90 minutes Oidium lactic 11 90 minutes Str. mastitis longus 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 fignires, giving the number of c. c.'s of oxygen formed, the relation between catalase and the time of reduction is as follows : Catalase Eeductase B. proteus vulgaris : . . 27 c. e. 7 minutes B. proteus eopfii 27 c. e. 5 minutes B. prodigiosus 27 e. c. 7 minutes Microc candic 27 c. c. 4 minutes Microc. A 27 e. e. 3 minutes B. coli 18 e. c. 5 minutes B. aerogenes 9 e. e. 10 minutes B. mycoides 7 e. c. 12 minutes B. dentrificans Ice. 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 tlie 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 H2O2. The catalase test is therefore recommended by Ivniisel 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 l)e 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 the\' have been subsequently formed by bacterial growth. AVolf claims that milk whicli reduces slowly and shows a strong catalytic property by tlie 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 vapid 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, etc., give to milk an acid reaction to phenolphthalein. Even immediately after milking, in order to produce neutral- ization of the milk against phenolphthalein, several c. c. of sodium hydrate are required. The number of culiic centimeters of a normal Na OPI dilution which are needed to neutralize a certain quantity of milk are known as degrees of aeidity. The number obtained varies, depending on the method and dilution employed. Thus Soxhiet-llenkel, for instance, employed 100 c. c. of milk and Yi normal N;i Oil and obtained an averaiic value of about 6 to 7 decrees of acidity. Jensen, who works with i„ normal Xa ( )TT, uses on an average 38 to 19 c. c. Thcirner dilutes 10 c. c. of milk with .">!• <•. c. of water and titrates with t'o normal Na OH. The degrees of acidity, as determined by Dornic, are hisher than those of SoxhIet-IIenkel: He uses 10 c. c. of milk and alkali which contains 4.445 gin. Na OH to 1000 H,0._ _,'„ c. c. of alkali, aecordins' to Dornic, 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 c. c. of which would correspond to 6.01 gm. of lactic acid, or to liiiure the decree of acidity on the basis of lactic acid. Then 1 c. c. of V,T alkali Avould correspond to 0.009 gm. of lactic acid and 1 c. c. of I'l normal Na OH=2:2.5 gm. Of course, it should be remembered that the neutralization oF the alkali iloes not correspond entirely to the amount of lactic iieid ]n-esent but (le])ends also on other factors, for instance, on tlie 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 tliat free lactic acid is not present in freshly drawn milk. 190 Reductase, Catalase, Etc. The degree of acidity of milk depends on the lactation period. Colostrum, milk of animals with affected 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 ndders, 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, etc. Plant, 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. Koniiig has also kept milk at various temperatures and titrated the degree of acidity after varying periods: Kept at 7 to 9 deg. C. Kept at 22 deg. C. Deg. of aciditv Deg. of acidity with l/o NaOH Milk after delivery 13. (i 13.6 After 15 hours. .' 14.6 14.6 After 29 hours 14.6 20.fi After 41 hours . 16.0 62.6 After 53 hours 16.0 71.0 After 65 hours 16.8 .... After 77 hours 17.6 After 89 hours 18.8 Since the growth of various bacteria depends on the method 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 Tn tall cvHnders delivery at 22 deg. at 37 deg. C. at 22 deg. ' at 37 deg. C. Shortly after milking. 18.6 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 )iy pouring from a height of i/o meter, 16.4; after repeated aeration 16.1, and after jjoiliug 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 Avith Avater for the purpose of titration (method of Thorner, Pfeifer, etc.), then through this addition of water, a solution of alkaline calcium phosphate takes place and the acidity becomes less. Typlioid Fi-\er from ]\Iilk. 191 Since the ar-idity varies immediately aftei' milkiiia,', after lac- tation, anioni;- individuals, and even in milk from different teats, anil from interrupted milkiuiis, the immediate measurino- of the dcurec of acidily constitutes no proof of the age of the milk. The l)eriodically continued titration of the same sample may, however, he a nood indication as to whether the milk has passed the incu- bation phase and there) ly afford an approximate indication of llic "age." By "age" is not understood the difference in time 1 let ween milking and examination, but a condition which may ap- jicar in milk sooner or later, de])ending on the cleanliness in its ])reparation and liandlim;-, and on the outside temperature. This condition is ell'ectively determined by the reduction of methylene l)lue. If the milk has once passed the incubation time the curve of acidity rapidly and progressively rises, when the milk is kept subse((uentlv at temperatures at which lactic acid bacilli grow pro- lilically (L'O'to ;!7 deg.). Kouing made a test of milk which at deliverv uave a decree of acidity of l.l.S (V^r n Na OH rlOO), And showed aft(^,- at 10 dei,'. 22 dr,-. 37 dr.,'. 0. 1 dav 1(;.4 I's.s l)(;.(i 2 daVs ](i.7 !»1.1 !i-'.S :! da'vs 17:2 1II-J.4 lo.").--' 4 daVs 17.9 9(14 144.0 5 davs -n>e, coagulum with h'ss uniform consistency. This ciian^c is not so ])ronouiiced with heating between 70 to SO (h'g. as in lidilini^- and in heating to over 100 deg. C. Dejjending on the height of the temperature and on tin- leniitli of time the heat is ai)plied, globulin (at 7.") t\v exchange of heat from the outgoing stream of milk about ono-half of the required heat jiiay 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 ^A^th 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 will 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- sf roytMl, 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 AVieske, 196 I^ffect of Heat. Burri, Eussell 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. Eelative to the effects of pasteurization, the following should be noted : As a result of the effect of 85 deg. C. the bacterial num- ber dropped from 10,000,000 to 500 per c. c. 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 eity of Leipsio 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 claim as this? According to the experiments of Forster, van Geuns, de Mann, Eingeling and Koning, de Jong, de Graaf, and Beck, the disease-producing bacteria are affected differently by high tem- peratures wliile 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 D.'iilli Point of lincteriii. 197 of tlie heat l)y the I'onnation of a surface scum and by coai^ilation. Dc Jon.i;- concludes from his exiicriments (bottle sterilization): 1. That heating- for a half hour at 71-7:^ deg. C. is not always sufticient to destroy the tubercle l)acilli mixed with the milk. -. That heating even to a higher degree does not always give sa1i>l'a('t(iry results since the I'csisting power of the tubercle bacillus varies. ;!. The designation "free from diseasc^-liacteria" for pas- teurized milk is false 4. Tliiise who desire milk fi'ee from tubercle bacilli must ])urchase sterilized milk, jd'ovided it is not obtained from herds free from tubei-culosis. Bang, de ]\Iann and Foister obtained evidence that heating to fi.') (\i"j;. C, for three nunutes destroys the tubercle bacilli, a fact which has also been cimlirmed by the work (if AVeigniann and l)y the experiments of Tjaden, Koske and Iler- te] under conditions whicli pi-evail in large disti-ibnting plants with milk from tulierculous udders. Otiiei- non-spore-containing dis- ease-])r()ducers in milk are also destroye(l at this tempei-ature jiro- vided that certain conditicnis do not pi-event ])ro])er heating. [According to the experinienis of K'osenau, it is evident that the tubi'rcle liacillus in milk loses its infective ])ropei'ties for guinea pigs when heated to ()0° (". and maintained r.t that temjid'ature for L'O minutes oi' to (i.")'^ ( '. for a much shorter time It should be remembered tluit the nulk in the tests of liosenau was ver\' hea\ily infected with \'irulent cultures, which was indicated by the ])rompt deaths of the control animals. ]\Iilk would jiractically never con- tain sucli an enormous amount of infection undei' natural condi- tions. It is therefore justifiable to assume that if fiO (' for twenty mimites is sufficient to destroy the infectiveuess of such milk when injected into the peritoneal cavity of a guinea ])ig, any ordim\ry market milk after such treatment would be safe for human use by the mouth as far as tubercle bacilli are concerned. These i-esults are substantiated by the findings of A'ersin, Bonhoft', Th. Smith, Schroeder, 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 ()0° deg. C and maintained at that temperature for two minutes. The great majority of these organisms are killed by the time the t(Muperature reaches .11)° 0. and few survive to 60° C. Tlu> diphtheria bacillus succumbs at comparatively low tem- peratures. Oftentimes it fails to grow after heating to 55^ C. Some occasionally survive until the milk reaches 60° C. 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 0,")° C., only once did it survive to (if)' ('. under the conditions of the experiments. The dvsenterv bacillus is somewhat more resistant to lieat than the typhoid bacillus. It sometimes withstands heatinu- 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° 0. 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 with 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 boiling, 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. XI, . TJie observation reeorrled by Sehut 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 efacient 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 oven converting it into material injurious to health. Preserving- ^Milk with Chemicals. 199 At that the additions do not accomplish the purpose for which thoy are intended in the dilutions in which they are used (Richter- boracic acid), or they diminish the utilization of milk for cheese production because they inhibit the rennet action. Soda or bi-car- bonate of soda, boracic 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,0o is added and it is then filled into bottles and kept for several hours at 50 deg. C. According to LuMn it is possible with pure peroxide of liydrogen, 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 tf) Chick, Eosain, Gordan, Bergmann and liultmann, Eicholz, Nikoll and Duclaux the amount of peroxide of hydrogen recommended by Budde is not sufficient for the satisfactory destruction of l)acteria in milk, but according to Lukin their failures wer(> due to the use of impure ])reparations of peroxide of hydrogen. Tubercle bacilli and typlioid liacilli were not destroyed l)y this method. If the authors used 0.1 '^r of peroxide of liydi'ogen, the necessary quantity to produce steriliza- tion, then the milk obtained a bitter taste, which disappeared only after the excess of liydrogen peroxide had been elimiiuited by cat- alase. According to ITtz a small quantity of peroxide of Jiydi-ogen is retained in the milk even when used in the quantities recom- mended by Budd(>. De Waele, Sugg and Vandevelde, who work(>d with 0.?> and 0.4% of peroxide of hydroi;en, have used in addi- tion small quantities of defibrinated blood for splittini;- up tli<' retained PLOo. ]\lucli and Romer employ a similar method of ]ireserving 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 prepar(Nl 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. Tnjui'ious 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 Effect of Chemicals. is 110 loiigei' resistant to decomposition through bacterial con- tamination, after the liepin has been added. 2. Years ago von Behring recommended the preservation of milk 1)Y 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 lieen 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 formaldeh^^de was found to be more effective in accord- ance with the cleanliness of the natural milk and this action ac- cording to Eothschild and Metter appears to result from the fact that the lactic acid bacilli chiefly succumb, 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 epithelium of the children, which leads to the elimination of albumin. Ac- cording to Baudini the rennet pepsin and trypsin action may be considerably inhibited by formalin; the acidity of the milk is increased. In the experiments of von Behring the action of formalin depends upon its effect in checking the development of bacteria, and not on its disinfecting or sterilizing property. A concentration of 1 :25,000 up to 1 :50,000 has no influence on the t;s7)lioid and colon bacteria and staphylococci (Vaughan and Schaps). Diphtheria, colon and pyocj'^aneus bacilli have not been destroyed even in dilutions as low as 1:5,000. Tubercle bacilli are protected by their waxy covering even against higher proportions of formalin, and as a matter of fact formalin is used, on account of its action on other bacteria, for the purification of sputum for the purpose of cultivating the tubercle bacilli from the saliva. Formalin milk constitutes a food which should be designated as spoiled and injurious to health. 3. Seiffert worked out a method of milk preservation in which the bactericidal action of ultra-violet rays is used for sterilization of milk. The method of action of the ultra-violet rays has not yet been satisfactorily explained. According to Lobeck (cited by Grimmer) the exposure of Avater to such rays produces peroxide of hydrogen. Grimmer believes that the latter is also formed in milk, but on account of the catalectic factors of the milk it immediately decomposes again. It is possible that the forma- tion of peroxide of hydrogen constitutes the germicidal power of ultra-violet rays. The milk fat is not changed (Lobeck). Ac- cording to Dreier-Hansen the proteid is coagulated after a pro- ritra-violet Rays. 201 1oii,l;(m1 exposure of milk to sueli rays. Seiffert passes the milk in bruail ))ottles along the illuminating bodies, allowing the rays to act upon tlie milk for about two minutes. He employed Leyden jars fitted with aluminum or cadmium points, which are charged with a current of high tension through an inductor which dis- charges mutually. Gerber and Hirschli used for sterilization the uviol light which is rich in ultra-violet rays ; he was unable how- ever to demonstrate a marked reduction of the bacterial content by subjecting a layer of milk of 1 mm. thickness to its influence, whereas Finkelstein and Lolieck, Henri and Stodel, Billon and Dagnerre obtained good results with the ultra-violet rays from mercury and quartz lamps. According to Billon and Dagnerre sterilization may also be accomplished when milk is exposed to white liglit in violet glasses. The action is the best when the white light is split up by a prism. Romer and Sames, who also conducted experiments on the l)actericidal action of ultra-violet light proved that market milk which has lieon exposed to the rays of a Hei-jius' mercury-quartz lamp of 6 ampere strength in a quartz a]eiul)ic (at a distance of 1.1 cm. from the source of light the action of which has lieen in- erejised ))y a refl(>ctor) caused a reduction from l)S,qi)() original bacteria after one hour of exposure to 10,500 l)acteria; after I'^'i hours to 8750; after 1^' '- hours to :2,050 bacteria. The taste of the milk was pronouncedly irritating. In a second test the number of liacteria (liminished from 111,800 to 94,000 in 10 minutes, and to (1.1, 500 in 20 minutes. On the surface of the milk a yellowisli scum forms. The peroxydase reaction of the milk is destroyed after a prolonged exposure to such light. [The experiments of Ayers and Johnson indicate that with (|uartz mercury va]ior lamps of the prescmt power and construc- tion it would not be possible commercially to completely sterilize milk by the ultra-violet rays. It might be possible to obtain bacterial reductions as great as l)v pasteurization even on a commercial scale by the use of large revolving drums and a number of lamps. However, in milk so treated tliere would l)e no assurance of the complete destruction of pathogenic organisms since the rays do not seem to exert any selective destructive action on vegetative cells. Of course since ])athogenic organisms might be assumed to be present in a small number in proportion to the total bacteria in milk, if 99.9 per cent. of the organisms present were destroyed, it might be assumed that the pathogenic bacteria would be destroyed. This process, however, would not afford the same security as does proper pas- teurization. Then, again, it would be difficult on a large com- mercial scale to constantly control the factors which influence the bactt'ricidal action of the rays. It is also doubtful if the lamps could be made to successfully 202 Effect of Chemicals. compete witli the present method of steaming milk bottles in order to partially sterilize them. From these experiments it appears doubtful if ultra-violet rays can be used on a commercial scale to replace the process of pasteurization. However, it may be possible to use the rays, in combination with pasteurization, in the preparation of a special milk with a low bacterial count, provided there is a demand for such milk in limited amounts for the use of infants and invalids. — Trans.] 4. Other methods of preserving milk are its saturation with carbonic acid under strong pressure, its ozonisation, and its sterili- zation with electrical currents. The carbonization recommended by Hoffmann, van Slyke, and Bosword, the ozonisation advised by Dorn, and finally the steriliza- tion through alternating electric currents of high tension recom- mended by Gruarini and Samarini have not yet attained any prac- tical significance. The best means of imparting keeping qualities to milk are cleanliness in its procurance; the only method of preservation Avhich should be generally permitted for milk is proper cooling. This concludes the theoretical consideration of milk. In the following chapter the method of control of milk in general will be discussed, and finally the method of milk examination will be taken up with emphasis on the points which appear especially important in the examination of market milk and for the ex- aminations of individual samples of milk. Chapter IX. MILK CONTROL. The sanitary police control of foods has advanced greatly in importance during recent decades. The study of diseases uf nutrition in general and the solution of the etiology of these affec- tions have resulted in a recognition of the necessity for the estah- lishment of measures relative to the quality of food sultstances, and have led to the formuhition of laws, ordinances and regulations. The most extensive (levelopmcnt in this relation is shown lir the importance of the meat-inspection law, which has been advanced to correspond with the value of meat as human food. Insteail of controlling the niarketaljlc meat prodmts in the shops, the most imjiortant part of the inspection is placeil at tlie point of meat production, that is, in the abattoirs. With the exception of the so-called home slaut;htered meats, not a sinf,'le pound of meat is consumeil or used for food products in (JcrniaTiy, without being first subjected to inspection. Tlie meat consumption per capita in Gennany in recent years has amounted to from 103 to 110 Ihs. In addition to tlie value of tlie meat produced, the amount of milk consumed should lie con- sidei-ed, there having been made an approximate estimate of an an- nual production of 7 billion gallons of milk, the smaller portion of Avliich is utilized as drinking milk, the larger part for the manufac- ture of milk products as cheese, butter, etc. According to statistical compilations, in 1905 the quantity of milk consumed per capita amounted in Berlin to 106.5 liters (30 gal.) in INlunich to 131.5 liters (37 gal.) in Hamburg to 137.5 liters (38 gal.) It is gratifying to note that the consumption of milk in Munich has increased during the last decade, and when its nutritive value is considered its low cost as a food stuff is quite apparent. The amount of milk and meat consumed in Munich per capita is as follows : 1900: ]\rilk 130 liters (36 oal.) Meat 81.8 kg. (180 lbs.) 1904: :\rilk 131 liters (37 oa].) :\reat 75.1 kg. (165 lbs.) 1908: Milk 149 liters (41 ,gal.) _ Meat 85.9 kg. (189 lbs.) and without doubt milk consumption will still continue to increase 204 Milk Control. if the cost of all other foodstuffs continues to rise. There are no means by which the nutrition of the people could be increased to better advantage than by increasing their consumption of milk, since it has not yet reached the high point warranted by the value of milk as a nutritive substance. From the various discussion in this work, the importance of supplying consumers with milk of good quality is apparent. An increase in milk consumption is of equal importance to the interest of the nutrition of the people and to the interest of agriculture. This increase however can only be obtained when, in addition to an educational propaganda regarding the nutritive value and cost of milk, care is taken to rectify the generally existing evils attend- ing its production, by which means the milk will be brought up to a standard, which may reasonably be required of any food. There- fore it should not only be unadulterated but must be produced and delivered in a clean manner, in an unspoiled, fresh condition, and possess no disease-producing properties. The important significance of healthy milk as food for the people, especially for infants, has been emphasized hy physicians, hygienists and A'eterinarians in numerons special articles, which have argiierl for and against the desirability of gaining nutrition through the use of market milk. Public interest and private philanthropy have accomplished a great deal of good by the establishment of infant milk depots.' Such establishments are frequently attached to the abattoirs, and are conducted under the successful direction of veterinarians. It is impossible to enter here into a discussion of such establishments, since this field constitutes only a small branch of the great question of the milk supply. While the determination of the causes of the so-called dis- eases of nutrition may not yet be sufficiently clear, the general and local surroundings of the patient or other conditions may influence the coiirse of these diseases. This is particularly true in summer mortalities of children, as in these diseases various conditions, such as want of natural nutrition, faulty housing, etc., may all play a part as factors. Nevertheless, from the experience of specialists the conclusion must be drawn that a strict sanitary police con- trol must be established in order to protect human health as much as possible from the ills occasioned by dangerous milk. Such harm may result from the consumption of : 1. Milk from diseased animals, 2. Milk originally wholesome but which has been suliso- quently contaminated with bacteria pathogenic for man, 3. Milk, which has been spoiled by any kind of decomposi- tion, or which is beginning to spoil, 4. Milk containing chemical preserving substances. These are briefly the points which in themselves prove the value of hygienic control of the milk traffic, and their elimination, with as much consideration as possible for the economic impor- tance of the various factors, must be constantly kept in mind. A proper execution of sanitary police regulations governing milk traffic is not only of importance for the health of the people A(lvanta,:^cs nf ^Nlilk E.\amiiiatiiiii>. i_'|),"i l»iit attains even greater value for the milk industry and general agriculture through the indirect advantages whicli result from their enforcement, such as the improvement of the herds, etc. Measures Avhich are in perfect accord with the hygienic require- ments of milk traffic, are at present enforced by most cities, whicli ha\c adojited various forms of ordinances and laws to cover this sul),ieet. Sdiiie of the states and the federal government also pro- vide f(ir certain additional control. The milk control stations of several cities in Germany have atteiii]i1e(l to pi'()duce an improvement of the milk traffic by the establishment of proper ordinances. Even the best organized stations confine themselves almost entirely to the control of the finished ])i'o(luct offered for sale, and therefore they are limited to the examination of sanijiles. If the existing distribution of milk and extension of delivei'ies in large cities are considereil it would require an army of officials to take samples and examine them, in (irder to test all the milk delivered to ascertain its value as food. E\'en in the eventual centralization of the milk ti'aflic, ap- propriate examination of market milk from a hygienic stan(li>()iiit will be impossible, since in each shii)nient too many que>ti(ins would have to be soIvcmI, and Ijesides this, we have not at nur com- mand reliable methods for examining the finished market milk rapidly and thoroughly. Tiie advantag<'s of nmrket milk examinations, which sliould not be underestimated, consist in the fact tluit it is ]Mi>sil)le to detect gross neglect and wilful violations, by which in many cn-^es guilty parties may he held i-espoiisilile. The knowh'ilge that he is under oltsei'vation, and tlu^ fear of punishnu'nt coiii|i:'l even the most indolent milkman and dealer to give increased attention to ])roduction and handling, including trans]mrtation. In some cities of (iennany a great deal has been aceomplislied in the con- trol of market milk, Init an effective improvement is i)reveiite