=Paranoiac Form.=—In this type delusions predominate and are characterized by variability, inconsistency, illogicality and transitoriness on the one hand, with many gradations to the opposite extreme where they become more or less fixed, and often dovetail into each other forming apparently a systematic whole. They tend to be usually of a persecutory and hypochondriacal character and in later stages when the mind is distinctly weakened are often of a grandiose type. Sometimes the patients have some kind of explanations for them and at other times none whatsoever, and they are often curiously dissociated from the emotional accompaniment. The patient may state there is poison in his food, in an indifferent tone of voice or even with a laugh; he may claim that his teeth are all set in wrong and offer no explanations to these obviously false ideas. The patient commonly thinks that somebody “has it in for him,” someone will do him mischief, will kill him, that people are talking about him and criticizing him, everything that he hears or reads he thinks has some bearing on himself, so-called “delusions of reference.” Hallucinations may be present, the patient hearing voices, or receiving impressions or ideas which he claims come from without. These external impressions he misinterprets as voices or forces which are accusing, threatening and slandering him. Later on, the patient tends to change from the depressed persecutory stage to an expansive one, when he claims he is some celebrated person, king or president, or pope. The impairment of the judgment is clearly demonstrated in these cases since the patient who may claim to be the king of England may beg the attendant to change his place at the table or for a postage stamp. =Pathologic Anatomy.=—This is obscure. Since a certain proportion of cases recover, there can evidently be no degenerative changes at the outset, though some cases deteriorate fairly early, others only after several years. In some chronic cases there have been observed degenerative changes in the cortical cells.