Sexes and statistics

Arthur Geissler's data for the distribution of the sexes in families with eight children, published in 1889, became famous through its use by R. A. Fisher in Statistical Methods for Research Workers in 1925 as an example of the binomial distribution. Geissler compiled data from Saxony for the period 1876-1885 for all family sizes. How did Fisher obtain the figures for his example? And why did he change the sixth significant figure of his value for the variance in his fourth edition of 1932?