A COMPEND

OF THE

DISEASES OF CHILDREN.

SECTION I.

ANATOMY AND PHYSIOLOGY.

1. The Tissues of a child differ chiefly from those of an adult in relative size, softness and elasticity.

2. The Circulation of blood in the fœtus is as follows: From the placenta, through the umbilical vein, which enters the body at the umbilical ring and passes to the under side of the liver. Here the current divides, a part going through the ductus venosus (see plate opposite) directly into the inferior vena cava (vena cava ascendens); the remainder enters the portal vein and, as in the circulation of adult life, passes through the liver, before entering the vena cava ascendens, and through it to the right auricle. Here the currents of the descending and ascending venæ cavæ join, but do not coalesce, for the bulk of the blood which enters the right auricle through the inferior vena cava does not follow the course of the adult circulation, but flows directly into the left auricle, through the foramen ovale and thence into the left ventricle and aorta, as in the adult. The course of the current entering the right auricle from the superior vena cava (descendens) is quite different, for this blood, in the main, passes through the tricuspid valve into the right ventricle, and thence into the pulmonary artery, as in the adult; but unlike the adult, the bulk of this blood never reaches the lungs, but passes directly into the aorta by the ductus arteriosus (Botalli), which passes from the pulmonary artery to the aorta,

entering below the origin of the great vessels. A small portion of blood flows past the ductus arteriosus into the lungs, via the pulmonary arteries, just sufficient for the growth and nourishment of the lungs, then passes through them, and, as in the adult, enters the left auricle, where it is mingled with the blood entering the same cavity via the foramen ovale, as described above, and follows subsequently the course of the adult circulation, until it at last enters the umbilical arteries, which are given off by the hypogastric arteries, and which convey venous blood directly from the fœtus to the placenta.

3. The changes in the foetal circulation which occur at birth are as follows:

(a) Disuse of the ductus arteriosus, owing to the expansion of the lungs, bending and thus obstructing this duct and relieving aortic pressure, with coincident closure of the foramen ovale. Neither the foramen ovale nor the ductus arteriosus become completely impervious immediately after birth, for the first may remain open for a month, and the ductus often is not entirely closed until the third month.

(b) Obliteration of the arteria umbilicales, in which, immediately after the detachment of the placenta, thrombi form, owing to the lessening of arterial pressure. The umbilical arteries thus occluded are later transformed into the lateral ligaments of the bladder.

(c) Thrombosis of the umbilical vein similarly follows the detachment of the placenta. This thrombosis extends past the umbilical ring to the bifurcation of the umbilical vein at the end of the transverse fissure of the liver, and fills the ductus venosus (Arantii) with a clot which eventually converts it into the ligamentum teres of the liver.

4. Weight of blood in newborn infant about 5 per cent. of body weight; weight of blood in adult 1 : 13, or about 8 per cent. of body weight.

5. Pulse at birth 130-150 per minute, irregular and very easily disturbed by slight causes; at end of first year, 100-120; second year, 100; fifth year about 90. Pulmonary blood pressure in the child is greater than in the adult.

6. Respiration varies with age and is easily disturbed; at birth, 40 per minute; from two months to two years, 25-35; from

two to twelve years, 18 when sleeping, and about 24 when awake, and is markedly abdominal. Lungs in children are relatively less, as compared with length and body weight, than in the adult. A sound child ought to breathe with its lips closed, through the nose, and excretes nearly double the amount of carbon dioxide for an equal amount of body weight compared with the adult.

7. Digestion.-(a) The alimentary canal is relatively longer in the child (vide Constipation), the stomach almost vertical, and its musculature is relatively weak. Digestion differs in several ways from that of the adult, e. g., in the absence of saliva during the first months, its place being taken by pancreatic fluid, whose fat digesting powers are slight during the early months of life, and at which time Brunner's and Lieberkuhn's glands are also not fully developed.

(6) The liver is relatively more vascular and larger than both lungs, up to puberty, when this condition is reversed. The bile contains only a small proportion of inorganic salts, cholesterin, lecithin and the bile acids, and especially glycocholic. (See Intestinal Indigestion.)

(c) The feces, with an exclusively milk diet, should have a bright mustard-yellow color, are of the consistence of ointment, feebly acid and contain about 85 per cent. of water, white flecks of fat, calcic lactates, traces of bilirubin, intestinal epithelial cells and mucus bacteria. These bacteria have not yet been fully studied and differentiated, but the bacterium lactis aerogenes, and various micrococci, seem to be fairly constant. 100 parts milk diet should produce about three parts of feces on an average.

(d) Meconium is the name given the dark-green feces first passed by the newborn child, from their resemblance to inspissated poppy juice. Meconium is viscid, odorless, feebly acid and consists of partially digested amniotic fluid, epidermal cells, fine hairs, cholesterin crystals and intestinal epithelial cells, but contains no products of decomposition nor bacteria when first voided.

8. Urine is secreted in utero, and is voided both before and often during the act of birth. The kidneys are relatively large at birth, and often show a peculiar reddish discoloration of their papillæ, produced by a deposit of uric acid crystals and urates, especially well marked in those children whose supply of oxygen

has been deficient at birth. If such children are not given water freely, there is insufficient fluid passing through the kidneys to dissolve these urates, which consequently appear as reddish-brown streaks or a brick-dust deposit in the tubuli uriniferi. This has been called uric acid infarct, and is of little pathological significance. The quantity of urine increases rapidly for the first five days, after that more slowly. At this time it averages from 12-13 ozs. (417 c.c.); after two years it reaches 15 ozs. (500 c.c.), rising to 18-19 ozs. (600 c.c.) at four years. The specific gravity of the urine increases up to the tenth day, after that it slightly diminishes. Average specific gravity, 1005-1010. The urine of early life is often turbid, dark and acid; later it becomes clear straw yellow and generally neutral in reaction. The excretion of urea is relatively less in children than in adults, and still less relatively are the phosphates. The same is true of chloride of sodium.

Traces of albumin may be normally found in the urine of the first days of life, but it should entirely disappear early.

9. Temperature at birth is 99° F. (37.7° C.), falling in a few hours a degree or more Centigrade (37.7°–36.2°), but rising again within thirty-six hours to about its initial height. The temperature in a young child is best taken in the anus or vagina; and it should be remembered that comparatively trifling causes in infants may produce relatively great variations in temperature, especially through depressing agents. In general, the temperature rises during the forenoon, reaches its highest point in the afternoon, begins to sink about six, and reaches its minimum in the early morning hours, shortly after midnight. It should also be remembered that in very young children the temperature may mark high (105–106°) without necessarily grave results, except in those predisposed to eclampsia.

Aphorism I.-Lowered temperature is found in anæmia, profuse hemorrhage, collapse, death agony and sclerema neonatorum, hydrocephaloid, and in children prematurely born. In early infancy there is no absolute relation between organic lesions and the height of temperature observed, for high fever, great restlessness, and even convulsions, may disappear quickly, and leave absolutely no lesions behind. (Bouchut.)

Aphorism II.—A temperature above 100° (37.8°-38° C.) during

the first four days of life is pathological. The same is true of rise of temperature during sleep.

Aphorism III.-The morning and evening differences in temperature in the fevers of children are, as a rule, greater than in the adult.

Aphorism IV.-High febrile heat with sudden chilling of the extremities is one of the frequent phenomena of fever in very young children.

10. The Skin of a newborn child is more or less covered with a smeary, white substance (Vernix caseosa), readily soluble in lard or vaseline, before the first bath, after which the surface of the child's body, if healthy, appears reddened, delicate in texture and covered with fine hairs. During the first week of life a quite extensive exfoliation of the epidermis takes place. The hair with which the head of the child was covered at birth gradually falls out and is succeeded by an after growth.

11. The Sudoriferous Glands secrete but little during the first weeks of life. The mammary glands of the newborn are not infrequently found in a state of congestion and enlargement, in both sexes, often sufficient to produce in them a few drops of a milky secretion. ("Hexenmilch," see Mastitis.)

12. Dentition commences usually at the seventh month, but it may be deferred till the twelfth to the eighteenth month, especially in rickets, even to the second year. When a child is born with teeth, they usually fall out early. The temporary teeth (twenty in number) are generally cut in pairs. The following table indicates, in months, the usual times of their appearance, above and below, thus::

The lower teeth usually are a little in advance of the upper. The permanent (thirty-two in number) appear in years as follows:—

At two years a child ought to have 16 teeth.