As a matter of fact, the population of institutions for insane criminals divides itself into two distinct and unmistakable groups. On the one hand we meet with the well-known functional and organic psychotic entities such as occur in individuals in freedom; we see patients who in the course of their careers as insane people have come in conflict with the law either accidentally or because of their insane ideas. In them the psychosis develops and takes its definitely determined course independently of the milieu in which the individual happens to be placed. In the majority of instances they suffer from the various forms of dementia præcox and progress toward demential end-results in the same proportion as the general run of dementia præcox cases do, whether or not they have come in conflict with the law. Occasionally we also see a case of organic brain disease or manic-depressive psychosis, and in more frequent instances a case of epilepsy. The other, and according to many authorities, by far the most predominant group of mental disorders met with in imprisonment, belongs to the so-called "prison psychoses", and bears definite, unmistakable ear-marks which differentiate it from the former group. These are, as we have stated, products of a particularly degenerative soil plus definite environmental conditions, and are of the utmost importance both from a purely clinical and an administrative point of view. The term "reactive manifestation", as applied here, is a happy one, and inasmuch as the accidental criminal differs from the habitual criminal as day differs from night, we will expect a different sort of reaction to a more or less similar situation in the two instances. To illustrate:--An apparently healthy and in most instances law-abiding and non-corrupt individual, as a result of a series of overwhelming and uncontrollable circumstances, commits murder in a fit of passion. Upon being arrested and upon the sudden realization of the enormity of his deed the entire constitution experiences a tremendous shock and reacts to it accordingly. He falls into a stupor, into utter oblivion of the world about him, becomes in turn excited and confused, his senses begin to functionate in a fallacious manner, and he thus succeeds in shutting out from consciousness, for the time being at least, the entire unbearable situation. Upon emerging from his stupor he has a more or less complete amnesia for the deed and its attending circumstances, and finding himself confronted with accusations, cross-examinations, and lastly, conviction, he at once sets about, so to speak, to square himself with the situation. What does he do? He develops a quite limited, well-organized delusional system in which he finds himself absolutely innocent, his accusers are the guilty ones, and the entire situation is nothing more nor less than a well-planned plot to destroy him. His supposed victim has not been murdered at all, but is living and