A practical treatise on infant feeding and allied topics, for physicians and students

Front matter

I-

Book

Copyright]^?-

Preface

The author's purpose in publishing a work upon ''Infant Feeding and Alhed Topics" is to meet the many requests received from his students and from' his medical colleagues who have honored him with: their confidence. The contents will be found to be largely clinical and practical, and to emlx)dy the author's personal experience with the problems presented. Theorizing and the presentation of a medley of views of different authorities have been studiously avoided. Credit has not always been given for views expressed which are not original, although the attempt has been made to do so where the fact stated is eminently new and, as yet, has not become a part of commoii medical knowledge. Quotations and references have been avoided as much as possible, as they are time-consuming and generally annoying, distracting the mind of the reader from the text. In not a few instances the author has indulged in the repetition of certain facts and statements. This has been done largely for the sake of emphasis and tO' insure the individual completeness of the presentation of the particular topic under discussion, and also to avoid references and cross-references.

A serious attempt has been made toi emphasize the importance of breast feeding and the digestive problems which present themselves in this class of patients.

The influence of the Gennan school of pediatrics has been presented in a conservative way, and simply includes vi PREFACE.

the author's personal experience with the ideas promiulgated by this brilhant coterie of workers.

Adherence tO' the percentage idea, in its broader sense, has been maintained, as furnishing a valuable method of thinking, and not as a ''conditio, sine qua non/' the idea being that individualization is the basic principle of successful infant feeding. The advantages and disadvantages of the caloric system have been discussed.

As a means of adapting milk to the individual requirements the top-milk methods and the mlilk-and-cream mixture methods have been abandoned as being to^o cumbersome, and often incomprehensible toi both the physician and to the caretaker. The dilution of whole or of skimmed milk is advocated as simple and efficient. Where their use has given goad results the author recommends a few pro^ prietaries, not as substitutes for, but as adjuvants to cows' milk.

The author's thanks are due, and are hereby gratefully acknowledged, to Prof. John B. Deaver, who. has written the article upon ^'Surgical Treatment of Infantile Pyloric Obstruction."

To his sister. Miss Sara Lowenburg, the author wishes to express his appreciation for her assistance while the work was passing through the press. To Robert A. Schless, senior student at Jefferson Medical College, and to Malvin H. Reinheimer, Esq., for their unselfish and enthusiastic assistance in reading proof, and preparing the index, the author is likewise gratefully indebted. The majority of the Rontgenograms were made by Dr. Geo. Ro'senbaum, of Mt. Sinai Hospital, Philadelphia.

PIarry Lowenburg.

1927 N. Broad St., Philadelphia, Pa.

CONTENTS,

Chapter I. Page

CHAPTER n.

Artificial Feeding 49

CHAPTER HI.

Artificial Feeding (continued) 118

CHAPTER IV.

Infantile Atrophy 150

CHAPTER V.

Rickets 185

CHAPTER VI.

Scurvy 222

CHAPTER VII.

Vomiting 232

CHAPTER VIII.

Constipation 247

CHAPTER IX.

(vii)

viii CONTENTS.

CHAPTER X.

PAGE

CHAPTER XL Exudative Diathesis 297

CHAPTER Xn.

Pyloric Obstruction 313

CHAPTER XHI.

Special Topics 350

Index 375

LIST OF ILLUSTRATIONS.

FIG. PAGE

1 The mammary gland (Gray.) 3

2 Artificial nipple or nipple-shield 7

3 Breast-pump. (Physician's Supply Co., of Phila.) 9

4 Massaging breast 11

5 Abscesses not interfering with breast feeding 12

6 Microphotograph of colostrum 13

7 Microphotograph of human and of cows' milk 15

8 Stripping of breast for sample 18

9 Lactometer. (Physician's Supply Co., of Phila.) 19

10 Creamometer for estimating] percentage of fat. (Holt) 22

11 Babcock's centrifuge tube for estimating fat. (Arthur H.

Thomas Co. ) 22

12 Babcock's pipette for estimating; fat 23

13 Eschbach's albuminometer used in protein test. (Arthur H,

Thomas Co.) 23

14 Types of good nursing breasts 31

15 How to hold an infant while at the breast 39

16 Proper can used in milking cows. (Dairyman's Supply Co.,

Philadelphia, Pa.) 64

17 Freeman's pasteurizer 92

18 Apparatus used in mixing formula 95

19 Nursing bottle 96

20 A good type of nipple 96

21 Bottle-brush (Physician's Supply Co., of Phila.) 97

22 Showing correct rapidity of flow of formula through nipple . . 98

23 Nursery refrigerator. (Courtesy of Gimbel Bros., Phila.) 99

24 Home buttermilk churner. (Gimbel Bros., Phila, Pa.) 122

25 Flour ball 134

26, 27 Essential marasmus 156, 157

28 Marasmus 158

29 Frog appearance in essential marasmus 159

30 Marasmus complicated by edema 161

31 Atrophy or marasmus due to chronic cerebrospinal meningitis . 167

32 Square outline of head in rickets 193

33 Rachitic kyphosis 197

35 Rachitic rosary 199

(ix)

X LIST OF ILLUSTRATIONS.

FIG. PAGE

36 Rachitic scoliosis 201

Zl Tubercular kyphosis 203

38 Pot belly and bow-legs 204

39 Rickets. Anterior bowing of tibia and pot belly 205

40 Rickets. Pot belly and protruding umbilicus 207

41 Double congenital dislocation of hip 212

43 Same child after recovery from scurvy 229

44 Constipation due to dilated colon. (Hirschsprung's disease.) . . 253

45 Massage balls. (Physician's Supply Co., of Phila.) 258

46 Percussion hammer 283

47 Lingua geographica 306

48 Showing pyloric obstruction 313

49 Weight curve in a case of complete or surgical pyloric ob-

struction 317

50 Effect of posterior gastroenterostomy on weight curve 318

51 Visible gastric peristalsis 319

52, 53 Weight charts of two cases of incomplete non-surgical

54 Weighing the baby 328

55 From combined weight of baby and towel subtract the weight

of towel to obtain result 329

56 Apparatus for stomach washing, etc 351

57, 58 Stomach washing 354, 355

59, 60 Colonic irrigation with the catheter 357, 358

61 Giving a colonic irrigation or a high enema without inserting

the catheter 359

62 Nasal feeding 362

63 Hypodermoclysis 371

64 Necrosis and ulceration from the subcutaneous injection of car-

bonate of soda and sodium chlorid solution 372

LIST OF PLATES.

PLATE FACING PAGE

Types of normal breast- and bottle- fed infants. .Frontispiece ^

I. Meconium (colored) 16 »/

II. Normal breast stool (colored) 28

III. Normal stool of artificially fed baby (colored) 32 "^

IV. Stool of indigestion in the breast-fed (colored) 36 -

V. Stool of dyspepsia ^(colored) 40 -

VI. Constipated, greasy stool of artificially fed infant, due

to administration of too much fat (colored) 64-^

VII. Hard, constipated, calcium-soap stool due to administration of too much fat (colored) 80 '

VIII. Hard, dry, whitish, constipated, crumbly stool, consisting of undigested protein, occurring in a bottle-fed

baby (colored) 104 •"

IX. Stool of a. case of diarrhea discolored by bismuth

(colored) 128

X. Same case as Plate IX. Diarrhea more advanced

(colored) 144 -

XI. Tubercular kyphosis 200

XII. The appearance of the gums in a case of infantile scurvy

(colored) 224^-

XIII. Showing stomach-tube i)i situ in a case of intense gas-

tric dilation 316

XIV. Practically complete obstruction 320

XV. Same case as Plate XIV. One hour after the administration of the bismuth 320

XVI. Same case as Plate XIV. Three hours later. No bismuth has left the stomach 320 -

XVII. Same case as Plate XIV. Six hours later 320 -

XVIII. Same case as Plate XIV. The next day, about nineteen

hours later 320

XIX. Comet-like appearance of the bismuth shadow at the

pylorus in cases of complete obstruction 320 -

XX. Non-surgical incomplete pyloric obstruction 336""

(xi)

xu

LIST OF PLATES.

PLATE FACING PAGE

XXL Same case as Plate XX. Two hours later 336

XXIL Same case as Plate XX. Bismuth still in stomach, four

hours after administration 336

XXIIL Same case as Plate XX. Much bismuth still in the stomach, but also seen in descending colon and

sigmoid 336

XXIV. Same case as Plate XX. Eighteen hours later 336

XXV. Case of incomplete but surgical pyloric obstruction 336

XXVI. Same case as Plate XXV. Bismuth in stomach, two

hours later 336

XXVII. Same case as Plate XXV. Four hours later 336

XXVIIL Same case as Plate XXV. Eight hours later 336

XXIX. Same case as Plate XXV. Sixteen hours later 336

CHAPTER I.

BREAST FEEDING.

MATERNAL AND MEDICAL RESPONSIBILITY.

Physicians have long recognized that the best food for an infant is human milk. In spite of this, thousands of children continue to be placed upon artificial feeding, some to thrive, some to live and to suffer from nutritional diseases, and some to die. The responsibility for the failure to conserve the maternal milk-supply, while dual, rests with greater weight upon the physician, who, while realizing the value of natural and the dangers and uncertainties of artificial feeding, has failed to become fired with that enthusiasm which, the subject demands. Consequently miany mothers are lacking in enthusiasm.

It must be stated, first, that the majority of women, providing they are disease-free, can nurse their young. The physician should, therefore, from the day that his patient cotmes under his charge for her expected confinement, point out to her at every opportunity the advantages of maternal nursing and the dangers of bottle feeding. It is a grave error, tooi often committed, to discontinue the breast at the first sign of indigestion in the newborn, — an occurrence so common that it may almost be regarded as normal. A mother, on the other hand, will frequently believe that her baby is not getting sufficient nourishment or that her milk is too weak o^r toO' rich, and that altogether she is unfit, both from her own and the standpoint of her infant's health,

1 (1)

to suckle her babe. The psychic element, represented by fear and uncertainty in the mothers mind, is a very potent cause for the discontinuance of maternal feeding and is exceedingly difficult and sometimes impossible to oivercome. In fact, fear and anxiety may cause a temporary suspension of the lacteal flow, just as of the other secretions, — saliva,, for instance. The physician here again fails in his function if he thoughtlessly coincides with the mother's ideas without investigation. True it is that there are contraindications to maternal feeding, but these will really be found to be few. In our zeal to secure some substitute for or imitation of human milk, we have been carried away from the truism that nothing is quite so good as the real article, and that, if we would but have it, there is plenty oi it at hand ; and that the study of its conser^^atioin is perhaps the most urgent duty of the pediatrist and of the practitioner.

The best guide as to a particular woman's ability to nurse is the physical condition of her babe. If its weekly gain equals from 5 to 7 ounces or even a little less, then nothing else need be considered. In spite of this, on the plea that the milk is insufficient in quantity and quality, although the simple process of weighing the infant before and immediately after nursing for a few times was not practised; or that the infant failed tO' gain weight (even in the absence of a milk analysis) ; or that it suffered from digestive disturbances, physicians are daily sacrificing the human milk-supply. Granted that these conditions are realities, one may pertinently ask ''Doi they constitute a sufficient reason to stop breast feeding?"^ Certainly not! As will be pointed out later, there are methods of conservation and of correction whereby the milk can be increased in quantity or whereby any or all of the various elements

MAMMARY GLAND.

may be augmented or diminislied. These it is the physician's duty to know and toi practise. The mother, on her part, should look to her medical advisor alone, and not depend upon the gratuitous advice of well-meaning but ])oorly informed friends.

Breast feeding may be done either by the motJicr (maternal nursing) or by a wct-nursc (wet-nursing). The

Fig. I. — The mammary gland. (Gray.)

former is by far the more satisfactory. The latter is useful in emergency. As the milk is secreted by the mammary glands, the construction and function of these organs should be understood.

MAMMARY GLAND.

The mammae, or breasts, secrete the milk and are two, large, hemispherical eminences situated on the lateral aspect of the chest, between the third and the sixth or seventh ribs, and between the sternum and the axilla (Fig. i). They vary in size in different woinen and in the same woman, depending upon the physiologic activity of the uterus. The left breast is a trifle larger than the right. Before puberty they are insignificant, but increase in size as the generative organs develop. During preg'nancy they enlarge and remain so during active lactation. The shape of the oirgan, as a rule, changes from a circular convex outline tO' a large, pendent mass. The nipple is a small, conical eminence placed just below the centre oif the gland. The skin covering the nipple and surrounding its base contains pigment, the amount and character of which depend upon the type O'f woman (blonde or brunette) and upon the activity of the gland. This pigment, called the areola, in the virgin is of a delicate rose tint. As pregnancy advances it beco'mes darker and spreads over a larger area,, extending from the base oi the nipple over the surface of the gland (secondary areola).

In brunettes of pronounced type this secondary pigmentation may be black. The skin covering the surface of the gland, besides being pigmented, also becomes striated much after the fashion of the skin of the abdomen. The nipple contains involuntary muscle-fibre, which, under sexual excitement or the irritation produced by the infant's lips, contracts, causing the nipple tO' become erect. The nipple is perforated at its tip by the numerous orifices of the galactophoroiis ducts. Around the base of the nipple are found several sebaceous glands which serve to keep the skin in a pliable condition (glands of Montgomery). Numerous nerves find their endings in the cutaneous papillae of the nipple.

Histologically the mammae are tubo'-racemose glands (Piersol), containing fifteen to twenty lobes, which are

MAMMARY GLAND. 5

/ separated and supported by masses of adipose tissue and by"

fibrous septa, which divide the lobes into lol)ules and these

again into acini. These acini are lined by a low columnar

epithelium, which varies in character, depending upon the

functional activity of the gland. These cells, resting upon a

membrana propria, rapidly multiply and oil-droplets appear

within them. These gradually increase in amount and

coalesce until they occupy almost the entire content of the

cell, crowding the nucleus and the protoplasm, to one side.

As the amount of oil increases the cells become distended

and finally rupture, the oil being discharged into the lumen

of the acinus, where, becoming mixed with an albuminous

secretion and epithelial debris, constitutes the secretion of

the gland, or milk. The cells near the centre of the acinus

undergo fatty degeneration and are discharged for a few

days following the establishment of lactation. These cells

constitute the large colostrum corpuscles (Fig. 6) which

persist for a week or ten days, and the first secretion is

known as colostrum. The nuilk is carried off by means of

ducts which extend from each acinus. These are called

lactiferous ducts, and they unite with those from other

acinii and foirm the lobular duct which joins with those

from other lobules, and finally this union terminates into

the lobar duct or galactophoroiis duct, which passes as a

single tube, ununited, from each lobe and opens by a separate

outlet intoi the apex of the nipple. Just before it reaches

the apex oif the nipple, eacli duct dilates into^ a pouch or

ampulla. These ampullae act as reservoirs for the milk.

The ducts are lined with low columnar epithelium' which

rests upon a membrana propria, and each duct possesses a

fibrous coat which contains elastic tissue and some unstriped

muscle-fibre. As the ducts approach the surface of the nipple the lining epithelium becomes stratified and continuous with that of the epidermis.

The internal mammary, the thoracic branches of the axillary, and the intercostal arteries supply these organs with blood, and their branches penetrate the entire gland, even surrounding the acini in a capillary network. The venous blood from the interior of the gland is carried by venules to the circulus venosus surrounding the nipple. Thence large branches carry the blood to the circumference, terminating in the axillary and the internal mammary veins. The lymphatics empty for the most part into the anterior axillary glands and some few into the anterior mediastinal glands. During lactation the vascular supply tO' the mammae is increased and the veins become decidedly prominent. The anterior and lateral nerves of the thorax supply the mammas with innervation.

HYGIENE OF THE BREAST AND NIPPLES.

After each nursing, the nipples are gently cleansed with a piece of absorbent cotton moistened with boric acid solution and gently dried. The infant's mouth is cleansed in a similar manner with a mild antiseptic alkaline solution. Before nursing the nipples should also» be cleansed. No' milk should be permitted to dry or to sour upon the nipple, as digestive disturbances are likely tO' follow as well as mammary infection. Excoriations and fissures of the nipples may cause excruciating pain. They can often be prevented by bathing the parts during the entire period of gestatiion with a solution of alum in alcohol, thereby rendering the epithelium tough. When present, temporary suspension of breast feeding may become necessary for a few days, or the artificial nipple may be employed (Fig. 2). Experience

HYGIENE OF BREAST AND NIPPLES. 7

with this instrument is not always satisfactory. It may, annoy the mother, and the infant may not take to it kindly. A better method is to withdraw the milk by manual manipulation, and to feed it to the baby through a bottle or by means of a spoon. The application of some sedative dusting powder, as equal parts of bismuth and boric acid, is often

Fig. 2. — Artificial nipple or nipple-shield.

serviceable. Before nursing, the powder should be carefully wiped away. Indolent fissures are stimulated to healing by touching them with a stick of silver nitrate. Compresses wet with a lo per cent, solution of argyrol or ichthyol are also useful. Better than all these is a paste made from equal parts of bismuth subnitrate and castor oil. An ointment of calendula, prepared by homeopathic pharmacies, applied to the sore places, has often yielded good results.

ECZEMA OF NIPPLES DURING PUERPERIUM.

Eczema of the nipples and of the neighboring integument is a troublesome complication of the puerperium and may seriously interfere with nursing. Water should be kept away from the parts. The condition usually yields to the combination of castor oil and bismuth. If there be present indurated fissures, salicylic acid gr. x and lanolin Ej will usually cause them to heal.

DEPRESSED NIPPLES.

The nipples may be depressed below the surface of the gland, or they may be inverted or even absent. The depression may disappear under the stimulus of sexual excitement or of the infant's lips. Depressed or inverted nipples may be a serious handicap' to maternal feeding. For this reason throughout the puerperium, the mother should be taught tO' daily draw the nipple out with her fingers or with the breast pump. It is surprising, on the other hand, to note, in some cases wherein the galactophorous ducts open directly upon the surface of the glands, with practically no nipple, with what ease the infant seizes the breast and maternal feeding is successfully accomplished.

CAKING AND ABSCESS OF THE BREAST.

If the milk enters the breast too rapidly, or if it fails tO' be withdrawn, by proper nursing, it collects in the lactiferous tubules and in the acini of the mammary gland, causing them to distend. This is known as caking. The breast becomes exceedingly painful and, especially in the dependent portions, are felt the hard and tender lobes of the gland. Caking is best prevented by regular and steady nursing. If in spite of this an excess of milk is secreted.

CAKING AND ABSCESS OF BREAST. 9

the breast pump (Fig*. 3) may be used to remove the excess, and the breasts are gently massaged with warm oil several times a day, care being exercised to make the stroke in the direction oi the ducts, from the base toward the nipple (Fig. 4, A and B).

Abscess of the breast is a preventable as well as a lamentable accident. It results directly from mammary infection. Infection may be carried into the lobules of the glands through cracks in the nipple, through eczematous excoria-

Fig. 3. — Breast-pump. (Physician's Supply Co., of Phila.)

tions, by the mouth of the infant, and by the decomposition of milk left to dry upon an imperfect nipple. The nurse or physician may carry infection to the breast by undue manipulation.

Symptoms.— Abscess may appear at any time during the nursing period. It is more common during the earlier weeks. There may be few if any constitutional symptoms. On the other hand, the general reaction may be severe, the patient complaining of chilly sensations or suffering a real rigor. The temperature rises to 101° F. or to 103° F. (rarely higher), and the pulse is proportionately increased. Anorexia and nausea, as well as headache and neuromuscular pains occur. The tongue is coated and the bowels become constipated.

Locally there appears a small or a large, circumscribed spot oif induration which is tender and which varies in size from a marble to a walnut. More than one such area may thus appear. The overlying skin becomes bright red. It is not at first adherent, but later becomes so. The color darkens, the area softens, often increasing to an enormous size, spreading not only superficially, but deeper into the substance of the gland. The skin is hot, the pain intense, and fluctuation is made out with ease or difficulty, depending upon the depth of the infection. Spontaneous rupture may occur with a disappearance of general symptoms, to be followed by slow healing and perhaps one or more remaining sinuses, which may or may not intercommunicate. These sinuses may persist for months.

Treatment. — Aside from incision and drainage, as soon as fluctuation manifests itself, the effect of mammary abscess upon the future ability of the mother to nurse her babe must be seriously considered. At first thought it would appear that a mammary gland, once infected, is lost to the infant forever. AA^hile true in most cases, one must discriminate and determine each case individually. The size and the position of the abscess, and^ also' zuhether or not pus is being secreted at the nipple, largely inftiience the decision. This may be recognized by the naked eye; or bacteria, pus cells, and perhaps blood may be discovered by the microscope. If the other breast be healthy it may yield sufficient milk. At least partial breast feeding should be employed. If on the other hand, as in a case in point, in which the abscess was as large as a marble and in which no- pus appeared at the nipple by reason of the fact that the galactophoroas duct leading to it, between it and the abscess, was obliterated by an adhesive inflammation, the infant will not receive any

COLOSTRUM.

is slow search sliould be made in the mother for tuberculosis or for some depressing diathesis. Change of air, good food, Basham's mixture or iron citrate, with other tonics, hypodermically, should be used. Autogenous or stock vaccines should also be employed as adjuvants.

Fig. 6. — Microphotograph of colostrum. A, the large nucleated and granular colostrum corpuscles ; B, oil globules.

COLOSTRUM.

About the third day of the puerperium milk makes its appearance in the mother's breast. This first lacteal secretion is not really milk, but consists largely of water and is comparatively rich in protein. It is known as colostrum and microscopically contains large, granular, corpuscular bodies, about five times the size of milk-corpuscles. They are known as colostrimn corpuscles, and probably represent desquamated epithelial cells which line the acini of the mammary gland (Fig. 6). Colostrum also contains globules of oil. Its composition is variable, as indicated by the table of Harrington, quoted by Rotch : —

I II III IV V

As indicated, the quantity of fat is comparatively low; while the percentages of milk-sugar and of proteins are high and uniform. The function of colostrum is but little understood. It probably does not contribute toi the nutrition of the infant. In fact, the reverse is true, for during the first week of life the infant's weight is diminished. Its effect is probably that of a laxative, ridding the bowel of meconium. ColoiStrum disappears in about one week to ten days, and is replaced by true milk.

CHEMISTRY AND PHYSICS OF HUMAN MILK.

Human milk, as well as cows' milk, is an emulsion. It is an opaque fluid, bluish white in appearance, and has a sweet, palatable taste. Its reaction is alkaline or amphoteric when freshly drawn. The specific gramty varies between 1029 and 1030.

Under the microscope the milk is seen tO' consist of a Uiiid portion and of corpuscular elements (Fig. 7, A). These corpuscles are minute, evenly divided, fat globules, which are held in suspension. When milk is acted upon by rennin and slightly warmed it coagulates. The coagu-

CHEMISTRY AND PHYSICS OF HUMAN MILK.

o

^fJ

Fig. 7.— Microphotograph of human and of cows' milk. I. Normal human milk showing uniformity in size of fat globules (A). The apparent smallness in the size of those in the centre is due to the focusing. Note the absence of epithelial cells and leucocytes. The presence of the latter would indicate inflammation of the breast, probably beginning abscess. II. Cows' milk showing the comparative irregularity in the size (larger) and shape of the fat globules (A) with reference to human milk. Also note the absence of epithelial cells and leucocytes, showing the teat to be free of inflammation.

lum consists of calcium paracasein (casein) or principal protein constituent of the milk, in the meshes of which are contained the fat globules. In the normal state this protein exists as calcium casein (caseinogen). From- the coagulum exudes a clear, watery fluid called whey. Whey contains the soluble and non-coagulahle proteins,^ lactalbumin and lad o globulin. The former is coagulated by heat; the latter is not. Whey also' contains the salts and sugar of milk in solution and a small amount of fat. Two-thirds of the protein in human milk are lactalbumin and lactofglobulin. In cows' milk but one-fourth of the total protein is composed of these constituents.

The chemical composition of human milk varies. It varies in different women and in the same woman at different periods of the same nursing and at different times throughoiut the entire period of lactation. The composition varies as to the number of daily feedings and the length of each feeding. It also depends upon the character and quantity of the mother's food, her environment, temperament, the care she has received during her accouchement, and the amiount of physical exercise. The nearer to nature a woman lives, the more normal will he her milk-supply.

The percentage of fat is the most variable constituent. It is the lightest element in milk, and, if the milk be permitted to stand, it rises tO' the surface and constitutes cream. Cream does not consist entirely of fat, but contains the other chemical substances found in milk. According to Holt, the ratio of the fat to the cream is as 3 is to 5. The fats of milk are composed of stearin, olein, and pahnitin, and are in fixed combinations, the amount of volatile fatty acids being decidedly less than in cows' milk.

1 Non-coagulable with reference to renin.

PLATE I

Meconium.

ANALYSIS OF IIUMAX MILK.

instruments is tedious and unsatisfactory. The pump and the bottle which is to receive the sam])le sliould be sterihzed. The color of human milk is bluisli wliitc in appearance. It has no characteristic odor.

A li

Fig. 9. — Lactometer. (Physician's Supply Co., of Phila.)

Reaction. — This is tested by litmus-paper.

Specific Gravity. — This is determined by an ordinary urinometer or a special lactometer (Fig. 9). The milk is put into a small cylinder, A, and the instrument, B, is lowered into the former with a slight spin to avoid sticking to the sides. When it has come to rest the graduation on the neck is read. The temperature of the milk should be 60° F. The specific gravity furnishes crude but valuable comparative data for clinical purposes. Thus the fat, being the lightest constituent of milk, when in excess would cause the specific gravity to be low, provided the other solid constituents were normal. Conversely, under the same conditions a high specific gravity would indicate that the percentage of fat must be low. If the percentage of fat is normal and the specific gravity is high, this would indicate that the remaining solids were high. The reverse means that there is a deficiency of the other solids. Therefore, too, if the specific gravity be normal and the fats are high, the other solids are high. If the fat be low and the specific gravity is normal, then the other solids are low.

Table Showing Relation of Known Percentage of Fat and Specific Gravity to Remaining Solids.

High fat and normal specific gravity = High remaining solids.

Low fat and normal specific gravity = Low remaining solids.

High fat and high specific gravity = High remaining solids.

Low fat and high specific gravity = Low remaining solids.

High fat and low specific gravity = Low remaining solids.

Low fat and low specific gravity = Low remaining solids.

Daily Quantity Secreted. — This is with difficulty determined, and can only be estimated by weighing a baby which is gaining steadily, before and after each feeding throughout the entire twenty-four hours. From several such daily assays an average can be struck. The following table from Holt^ gives approximate quantities which may serve as a guide : —