Süssmilch, a German army chaplain, produced an important book on vital statistics, the title of which translates as The divine order in the circumstances of the human sex, birth, death and reproduction.  Among other things, he showed the necessity of a healthy and industrious population for the survival of a nation. Süssmilch discovered that, in the long term, there is a constant sex ratio of 1,000 female births to 1,050 male births. His work was the most important until the time of Malthus. Digital facsimile of a printed facsimile of the first edition from the Hathi Trust at this link.

Twenty years after publication of the first edition (No. 1691), Süssmilch published a second edition "that was so different from the earlier book that it may well be called a separate work. While maintaining his original demographic theses, Süssmilch enlarged the scope of demographic enquiry to the field of social and economic policies. Many commentators have alluded to the differences between these two editions (Arisawa, 1979, p. 23; Hecht, 1980, p. 670; Rohrbasser, 1996, p. 984; Dreitzel, 1986a, p. 43). Still, the evolution of Süssmilch’s work has not yet been adequately highlighted and even less explained in the context of the population debates of his time.... Süssmilch radically changed his project and his outlook on the purpose of assembling demographic material in the twenty years between the two separate editions. The latter one deliberately forms part of the German political and economic discourse of the second third of the eighteenth century, while his previous intervention showed no signs of knowledge of this discourse and little interest in contributing to it. This reading of Süssmilch is informed by the assumption that the erudite discourse on population development and the debates about population politics were largely separated in the Holy Roman Empire of the German Nation, thus differing from the situation in Western Europe" (Nipperdey, "Johann Peter Süssmilch: From divine law to human intervention," Population, 66 (2011/3) 611-636).

Digital facsimile from the Hathi Trust at this link.

A three-volume critical edition including the first edition in French.