Sankey[274] in 1884 included in his idiopathic psychoses due to pathological conditions, general paresis and "ordinary insanity." "This is the disease which in its course presents such varying phenomena, and has thus given occasion for multiplying the names." Prominent in this group were the various forms of mania and melancholia and it undoubtedly included dementia praecox. "Like other diseases it may be artificially divided into separate stages, and this is useful for facilitating description, but such artificial divisions must not be looked upon as different species of disease." ... "Thus, a case in the primary attack commences by symptoms of melancholy; these may, when successfully treated, pass off, and the patient recover, or the melancholic stage may be aggravated, and the patient die in this stage;—the disease may exhibit symptoms of violence and become acutely maniacal. There is no ground on this account to say, that the patient has a new disease, any more than the appearance of an eruption in an eruptive disease would be the inauguration of a different kind of malady." Although obviously he had no idea as to the fundamental differences between manic-depressive insanity and dementia praecox, he unquestionably was one of the first to emphasize the fact that mania and melancholia were often definite stages of one disease process. In 1896 Kraepelin described melancholia as essentially an involutional condition. Under the heading of periodic constitutional disorders he included mania, circular and depressive forms, the mania, melancholia, and circular insanity of other writers. Schüle[275] in 1886 described circular, periodical and alternating psychoses. In 1894 Ziehen[276] included in his classification under the heading of combined psychoses a "melancholisch-maniakalisches" form in addition to mania and melancholia, which he spoke of as affective psychoses.