The first really worthy contribution to this subject was made by Siefert,[4] the physician in charge of the psychiatric department of the penitentiary at Halle. He published, in 1907, the results of a study of eighty-three prisoners who became insane while serving sentences. He divided his patients into two sharply differentiated groups, the true psychoses, _i.e._, the well-known forms of functional and organic mental disorders, and the degenerative psychoses, _i.e._, psychotic episodes developing upon a soil of degeneracy and which according to him form the typical prison psychoses. Before we go any further it must be mentioned that Siefert did not take into consideration the mental disorders developing in prisoners awaiting trial. "The true psychoses develop out of endogenous causes, attack and manifest themselves in the prisoner in the same way as in any law-abiding individual in freedom. They are not essentially influenced by changes of environment and there exists no intimate relation between the coloring of the symptomatology and the influence of the imprisonment. The degenerative psychoses, on the other hand, develop upon the well-characterized degenerative soil of the habitual criminal, and are products of predisposition plus environmental influence. They stand in the most intimate relation to the deleteriousness of prison life, and are therefore influenced to the greatest extent by change of environment." On studying critically Siefert's work one gains the conviction that the author not only undertakes to solve certain clinical questions, but endeavors to investigate the problem of the relation between crime and mental disorder. Although he paid the strictest attention to the individual symptoms and described in an excellent manner the manifold and varying symptomatology of these psychoses, he did not succeed in isolating a symptom-complex which might be considered as typical of the degenerative psychoses, and thus deserve the independence of a distinct clinical entity. Above all he occupied himself with the investigation and delineation of the various anomalous individualities, the degenerative constitutions upon which these psychotic manifestations engraft themselves. Thus he divided his prison psychoses into groups like the "simple degenerative", "hysterical degenerative", "phantastic degenerative", etc. Siefert undoubtedly overshot the mark in his clear-cut differentiation between the various types, but he unquestionably contributed a most important work on this subject.