Grain prices and mortality: A note on ‘La Michodière's Law' ∗

∗ Our thanks to George Grantham, Antoin Murphy and two referees for helpful comments on an earlier draft and to David Weir for sharing his French price data with us.

Abstract

In a postscript to his Recherches sur la population (1766), political arithmetician Louis Messance made the case for a positive association mortality and the price of wheat. The true author of the postscript was probably Jean-Baptiste François de la Michodière (1720 – 97), Messance's mentor and employer. The calculations given in this paper offer tempered support for what is dubbed ‘La Michodière's law’. There was indeed a correlation between prices and mortality in early eighteenth-century France; but La Michodière's own and other data imply that even then it was weaker and less mechanical than implied by some of his successors.

Keywords:

• Corn prices
• mortality
• economic demography
• famine

Notes

∗ Our thanks to George Grantham, Antoin Murphy and two referees for helpful comments on an earlier draft and to David Weir for sharing his French price data with us.

1 Although curiously overlooked by J.A. Schumpeter (1954).

2 For excellent appraisals of his career and work, see Feinerman (1980, ch. 13) and Brian and Théré (1998). See also Bru (1988).

3 Letter from Adam Smith to David Hailes, 15 January 1769, cited in Smith (1976: 216, fn19).

4 Compare Brian (2001). Sir Francis Galton (1822 – 1911) was responsible for both the concepts of correlation coefficient and statistical regression.

5 The towns (départements) included are the following: Bourg-en-Bresse (Ain); Annonay (Ardèche); Aubenas (Ardèche); Charleville (Ardennes); Pamiers (Ariège); Strasbourg (Bas-Rhin); Aix (Bouches-du-Rhône); Arles (Bouches-du-Rhône); Hôtels Dieu Bayeux (Calvados); Bayeux (Calvados); Angoulême (Charente-Maritime); Saint-Brieuc (Côtes-du-Nord); Perigueux (Dordogne); Buis-les-Baronies (Drome); Romans (Drome); Chartres (Eure-et-Loire); Chateaudun (Eure-et-Loire); Pont-St-Esprit (Gard); Grenade-sur-Garonne (Haute Garonne); Toulouse (Haute Garonne); Beziers (Hérault); Rennes (Ille-et-Vilaine); Montbatzon (Indre-et-Loire); Tours (Indre-et-Loire); Grenoble (Isère); Boen (Loire); Saint Étienne (Loire); Angers (Maine-et-Loire); Coutances (Manche); Langres (Marne); Laval (Mayenne); Douai (Nord); Lille (Nord); Beauvais (Oise); Chaumont (Oise); Lyon (Rhône); Paris (Seine); Rozoy-en-Brie (Seine-et-Marne); Pontoise (Seine-et-Oise); Abbeville (Somme); Montdidier (Somme); Albi (Tarn); Montauban (Tarn-et-Garonne); Draguignan (Var); Poitiers (Vienne); Limoges (Haute Vienne).

6 For more on these famines, see Lachiver (1991) and Ó Gráda and Chevet (2002).

7 The estimates refer to départements, an administrative unit devised nearly a century after the events discussed here. In several départements the lack of data means that the estimates of births, marriages, and deaths stem from very small non-random samples of parish registers. In nine cases the départemental estimates are based on either two or three parishes; in the case of Haute-Savoie only one usable register survives (Séguy 1998: 198 – 204). Urban populations present particular problems. Moreover, many seventeenth-century registers suffer from omissions and gaps (Bonneuil 1998), and a considerable under-registration of deaths, particularly those of infants and children. There is no sure way of knowing whether under-recording was more serious in crisis years. Nevertheless, the INED database casts new light on what has been hitherto a ‘demographic dark age’. For the purposes of this paper a few minor gaps have been plugged in the dataset by simple interpolation, but there has been no interference otherwise with the numbers in the INED series.

 In their contribution to Histoire de la population française in 1988 the leaders of the INED enquête noted the provisional status of their data, but doubted whether further refinement would modify the general outlines (Biraben et al., 1988: 145 – 6). Of the three series in the database – baptisms, marriages, and burials – the last is almost certainly the least reliable (Biraben et al., 1988: 151). Still, Cabourdin (1988: 208) write: ‘on peut mieux définir la géographie de cette crise, les données étant pratiquement complète à cette époque.’ And they reproduce data by département (Figs. 69 – 72). Internal migration data are lacking, however.

8 Thanks to INED and particularly to Alain Blum for providing these data. The dataset used here is an improvement on that used in Cabourdin (1988: Figs. 69 – 72), which lacked information on several départements.

9 However, the data for Nord seem particularly shaky.

10 The correlation between estimated excess death rates across départements is only 0.12.