In a certain number of cases, after the period of excitement disappears, a certain amount of dementia is noticed. This consists of a distinct lowering of the intelligence, though without the presence of any special delusion. This dementia progresses until finally there is a state of almost complete obliteration of the mental faculties. The prognosis as to life in cases of mania is very good. Very few patients die during an attack of acute mania. At times there is a development of tuberculosis that proves fatal, because of the restlessness of the individual. Pneumonia or typhoid fever may also prove fatal. Besides mania or melancholia, there is a third form of functional mental disease, which is a combination of these two forms. It is usually spoken of as circular insanity. The patient has usually first an attack of melancholia, then an attack of mania, and then after an interval melancholia and mania once more. We have said that most cases of mania develop after a distinct stage of depression of spirits, so that successive attacks of mania take partly the character of circular insanity. This latter disease, however, is an index of a much more degenerated mental state of the individual than is either mania or melancholia alone. When it occurs, the prognosis as to future sanity for any lengthy interval is unfavourable. A series of attacks alternately of depression and excitement finally make it necessary to confine the patient to an institution. As might be expected in this severer form of mental disturbance, heredity plays an especially important part in circular insanity. At least 70 per centum of the patients affected show a family history of insanity in some forms. In this disease direct inheritance of this particular form of {229} mental disturbance is noticeably frequent. The patients who develop this form of insanity usually show marked signs of degeneration, even before any attack of absolute mental disturbance has occurred. Wounds of the head, alcoholism, and epilepsy are prominent factors in the production of circular insanity. This only means that the predisposition to mental disequilibration is so strong that but very little is required to disturb the intellectual equilibrium. Fortunately, circular insanity is rare. In 40,000 cases of insanity in New York State, only 96 cases of this form were noted. Mild types of the disease are not, however, very rare. Many otherwise sane people have alternating periods of hopeful excitement and of discouraging depression, not momentary but enduring for weeks at a time, which are really due to the same functional disturbances that in people of less stable mentality produce absolute insanity. These cases are of special interest to the clergyman and to directors of consciences. JAMES J. WALSH. {230} XVIII NEURASTHENIA