Infant nutrition : a textbook of infant feeding for students and practitioners of medicine / by Williams McKim Marriott.

  • Williams McKim Marriott
Date:
1930
Catalogue details

Licence: In copyright

Credit: Infant nutrition : a textbook of infant feeding for students and practitioners of medicine / by Williams McKim Marriott. Source: Wellcome Collection.

    29/412 page 25
    The Blood The total volume of the blood, as well as the red cell and hemo¬ globin content, is higher at the time of birth than at any other period during life. Considerable destruction of the excess blood occurs during the first week or two of life, the conversion of blood pigment into bile pigment being in part at least responsible for the icterus of the newly born infant. The volume of the blood at birth is stated by Lucas and D earing to average 14.7 per cent of the body weight. After the neonatal period this volume falls to 9 or 10 per cent of the body weight. In the case of infants who have been underfed or who have become dehydrated, the absolute volume of the blood is decreased, but not necessarily to the same extent as the decrease in weight. A de¬ crease in the blood volume is regularly associated with a marked impairment of the circulation. We have observed malnourished and dehydrated infants in whom the volume flow of the blood in the extremities was less than one-tenth of the normal. The volume flow in the internal organs, although not susceptible to accurate measurement, appears also to be decreased, and results in a diminished degree of absorption from the gastrointestinal tract as well as functional incapacity of the heart and of some of the secreting organs. The hemoglobin content of the blood at birth varies from 100 to 120 per cent (based on a scale of 100 per cent for a normal adult). By the third week the hemoglobin has usually fallen to about 90 per cent. A slow decrease then occurs for the next four or five months, so that by the end of the fifth or sixth month the hemoglobin has fallen to 75 or 80 per cent. From this time on the hemoglobin content of the blood is largely dependent upon the character of the feeding. If an infant receives only milk, whether it be human or cow’s milk, a progressive decrease in hemoglobin occurs. If, however, the diet contains green vegetables, meat and eggs, any further marked reduction in the amount of hemoglobin does not usually occur. The fluctuations in hemoglobin are to be explained by the fact that as the infant grows the blood volume increases proportionately, the total volume of new blood formed during the first year of life amounting to from 20 to 25 ounces (600 to 750 c.c.). If a normal hemoglobin content of this newly
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