One should never judge a book by its cover. But let's be honest: sometimes the cover is just better than the content of a book. And sometimes, that is the case for maps as well.
This map is a Paris metro map from the late 1920's. It is a 'Plan Officiel du Métropolitain', but it is a sponsored one. And by nothing less than the Association de Propaganda pour le Vin. This society from the city of Béziers in the French Midi propagated the use of wine.
The text on both sides of the map translates to "Wine is the most healthy and most hygienic of all drinks". A quote from Louis Pasteurs essay "etudes sur le Vin' from 1866. This essay revolutionized French wine making, and made Pasteur a national hero. Pasteur found that yeast should be encouraged to grow, while bacteria had to be eliminated. This could be achieved by heating wine to 50–60 degrees Celsius, the process we know today as pasteurization. In times where water was often contaminated with bacteria, wine was (in terms of bacterial contamination) often a safer drink.
The text above the map urges the reader to prefer restaurants that include a glass of wine in their fixed-price menu. On the back side of the map is an extensive list of all Paris restaurants that offer this service.
But the cover is even more interesting. On the front is a portrait of Pasteur, and again his famous quote.
On the back of the cover another slogan: "Drinking wine prevents alcoholism". This way of thinking about alcohol is very different from the way we look at it now. There is no real difference in the toxicity of alcoholic beverages. It is the amount of alcohol that counts. So one gram of alcohol from wine is as toxic as one gram of alcohol from beer, or gin, or any other drink. But that is of course not the message the winegrowers from the Midi want to share. And it was probably not only marketing: most problematic alcohol use was associated with stiff drinks, like gin, in bars and cabarets, and not with drinking a glass of wine with a meal. But that of course reflects socio-economic differences, that are much more important then the type of drink persé.
But there is more. Doctor Jacques Bertillon is quoted: "In the regions were people drink wine, tuberculosis is less widespread." Bertillon was a French physician with a strong interest in statistics and epidemiology. He was convinced that alcohol played a very important role in the epidemiology of tuberculosis. This quote is illustrated with a map showing the prevalence of tuberculosis per department. A line shows the Northern limit of wine culture. Of course, this map does not prove that the consumption of wine prevents tuberculosis. This map does not show were wine is being consumed (let alone in what amount), but where it is made. And to be honest, not even that: it shows the most Northern limit of were vines are grown. But in over 80% of the area below that line, no wines are being made. But Bertillon was sure that strong drinks like eau-de-vie were the problem, and suggestions were even made to lower the taxes on beer, wine and cider, in order to prevent tuberculosis.
In his book "Guerre à l'alcool"- War against alcohol - Bertillon included a map that showed the annual consumption of alcohol (in liters) per person. Again, we can identify the 'wine-line'. And we can observe that more alcohol is consumed in the North of France, compared to the other parts of France. The suggestion Bertillon often made, is that were wine is being made, people tend to drink less strong alcoholic beverages.
Associations do not imply causality. Often associations occur because both factors are related to other underlying phenomena. In the case of alcohol / wine and tuberculosis, the association is likely caused by conditions like poverty, population density and general health (which of course are all closely related).
But probably, the reader of our map, finding his way in the Paris metro, was not aware of all these finesses. He was hungry, in search of a meal, and grateful for the restaurant suggestions on the back of his map. And wondering were his sudden appetite for a carafe of wine came from...