In 1854 at the Academy of Medicine in Paris Falret presented his "Mémoire sur la folie circulaire, forme de maladie mentale caractérisée par la reproduction successive et régulière de l'état maniaque, de l'état mélancolique, et d'un intervalle lucide plus ou moins prolongé." In the same year Baillarger described his "Folie à double forme," summarized by him in a Bulletin of the Academy of Medicine as follows:— "(1) Besides monomania, melancholia, and mania, there exists a special form of insanity characterized by two regular periods, one of depression, the other of excitement. (2) This form of insanity: (1) presents itself in isolated attacks; (2) reproduces itself in intermissions; (3) the attacks may follow each other without interruption. (3) The duration of the attacks varies from two days to one year. (4) When the attacks are short, the transition from the first to the second period takes place suddenly, and generally during sleep. It takes place slowly and gradually when the attacks are prolonged. (5) In the latter case, the patients seem to enter into a state of convalescence at the end of the first period, but this return to health is incomplete; after a fortnight, a month, six weeks or more, the second period breaks out." This was described as "Folie à double phase" by Bellod, "Folie à formes alternés" by Delaye, "Délire à formes alternés" by Legrand du Saulle, "Die cyclische Psychose" by Ludwig Kirn and "Das circuläre Irresein" by Krafft-Ebing. At a meeting of the American Association in 1886 the classification of the British Medico-Psychological Association was adopted with the omission of moral insanity and the addition of toxic insanity. This included the following types of mania:—Recent, chronic, recurrent, à potu, puerperal and senile, and classified melancholia as recent, chronic, recurrent, puerperal and senile. In his "Clinical Lectures on Mental Disease" Clouston in 1898 described eight varieties of melancholia and six of mania, not including alternating forms. Kahlbaum in 1882, reverting apparently to the phraseology of Flemming, spoke of dysthymia, hyperthymia and mixed or circular forms—cyclothymia. Many of the conditions afterwards classified under dementia praecox he described as "vesania typica."