From a letter to the editor printed in the April 22, 1910 NYT:

Mr. Schaefer of the New York Brewers' Association states that "insanity has not diminished where the liquor traffic is supposed to be driven to the wall."

[the letter goes on to list several states and the number of liquor dealers and "insane" - see below]

...

Mr Schaefer refers to the relation of intemperance to to pauperism. May we point out that in a book called "Text Book of True Temperance," compiled, published, and distributed in great numbers by the United States Brewers' Association, it is admitted that an examination of over 80,000 cases of pauperism showed 87.95[?] per cent. caused by drink?

The temperance movement, at this time, has been making considerable progress around the country. One argument offered for banning alcohol was the reduction in "mental disease" - however roughly that was defined in 1910. This letter tries to show that where the liquor traffic still persists that there is "more insane" individuals.

The letter writer relies upon the reader to do some mental computations to determine the correlation between the number of liquor dealers per capita and the number of "insane" per capita. Luckily, I have Stata.

Assuming the letter-writer's data are correct, the correlation between the number of liquor dealers per-capita and the number of "insane" per capita comes out to be 0.88. Here's a scatter plot of the data:

Of course, one has to ask whether this is causation or correlation.