Non-tuberculous Tuberculous ======================= ======================= FIRST-BORN LAST-BORN FIRST-BORN LAST-BORN ========== ========= ========== ========= Paternal Family 33.9 37.2 40.6 49.9 Maternal Family 34.6 37.5 40.0 53.4 Comparison of the mortality of the First and Last-born, The mortality of the First-born = 100. Non-tuberculous Tuberculous ======================= ======================= FIRST-BORN LAST-BORN FIRST-BORN LAST-BORN ========== ========= ========== ========= Paternal Family 100 108 100 128 Maternal Family 100 108 100 134 Figure C 56.] [Sidenote: C 57] Of a materially greater influence than the numerical position of birth or the number of children in each family is the length of interval between births. We point at first to Figure C 57--+interval between births and child mortality+, after Ansell and Westergaard, by Dr. A. Bluhm. She writes in reference to it: "Ansell has demonstrated, from the material of the National Life Assurance Society of London, that a child has an increasingly better chance to survive his first year, the greater the interval between his own birth and that of the child born before him. If this interval is less than a year, the infant mortality is double what it is when there is an interval of two years (15.75% against 7.33%). This influence makes itself felt beyond the age of infancy up to five years but not in so striking a manner. The proportion becomes modified to 20% against 12%. As the influence of the birth interval on child mortality is still very perceptible after the tenth or later children, it may be assumed that it is not caused exclusively by the exhaustion of the maternal organism produced by the rapid sequence of births. The varying length of breast-feeding of the children has probably also its influence. Though these statistics give no data about the mode of infant feeding, it is nevertheless probable that in those families in which there are longer intervals between consecutive births each child is suckled for a longer period. [Sidenote: C 58] +Birth interval and health of the offspring+, after Riffel--v. d. Velden. [Sidenote: C 59] +Influence of the length of the birth interval and the duration of breast-feeding on infant mortality+, exhibited by Weinberg. The author writes regarding the latter table "in proportion to the length of the interval between two births, the mortality of the children following decreases materially, but this relation only becomes clearly apparent in families in which several of the children have been suckled for more than six months." [Sidenote: C 60, 61 62]