On November 21, 1822, a young man named A. L. J. Bayle presented a thesis for the Doctorate of Medicine to the Faculty of Paris. It was entitled “Recherches sur les Maladies Mentales,” and it was sustained. In this thesis Bayle recorded the opinion that general and incomplete paralysis and mental disorder, when they developed side by side, were caused by chronic arachnitis. In other words that these two groups of phenomena—a certain form of paralysis and disorder of the mind—were the associated symptoms of a definite disease, having a distinctive pathological anatomy. This was an opinion never expressed before by anyone, and it has since then been proved to be true in its essential features. The disease he referred to is now known as general paralysis of the insane.