Changes Occurring in the Blood Picture During Fetal Life

Abstract

While studying the blood of newly born infants, the characteristics of the blood picture at that period were observed to differ from those of the adult in a very interesting manner. In brief, the erythrocytes were present in greater numbers, were of greater mean volume, and the hemoglobin content was higher than normally seen in human adults. These observations raised the question concerning the nature of the factors which effect those alterations between the blood pictures of the 2 periods of life. The possibility was also suggested that a clear understanding of these factors might aid in the elucidation of the mechanisms of various blood dyscrasias of adult life. With these ideas in mind it seemed advisable to establish first the normal course of blood changes which occur in the fetus during intra-uterine life, and then later to investigate the mechanism of their production. The present work deals with a series of blood studies on embryos of the domestic pig, Sus scrofa.

This experimental animal was chosen because its blood is very similar to that of the human and because experimentation of recent years has demonstrated the presence of the so-called anti-anemic principle in the mucosa of the hog stomach. This latter fact suggested the possibility that this substance may exert a similar controlling effect on the hematopoietic function in the pig and in the human—as well as in various other animals less adaptable to laboratory experimentation. Support has been given to this idea by the work of Miller and Rhoads 1 who, working with the pig, produced a form of hyperchromic anemia with associated gastric anacidity by means of dietary restriction. Extract made from the livers of these anemic animals was not therapeutically effective when administered to patients suffering from pernicious anemia.

While work on the present series was in progress, Wintrobe and Shumacker 2 published a large series of blood studies on fetuses of various animal species, including the pig. Our findings corroborate their observations on the latter, and since a thorough review of the pertinent literature was included in their paper it will be omitted here.