Note on Dr. D. W. Montgomery's Case of Teratoma

Through the cou~esy of Dr. Montgomery I have been permitted to study sections from his tumor and to make (1) a note upon the nervous tissue present, and (2) some remarks concerning the theories which have been advanced to explain teratomala in general. I. The tumor contains large masses of nervous "tissue distributed throughout its substance. While most of this nerve tissue resembles embryonic brain, including the lining of the central cavity with chori-old plexus, some medullated nerve fibres were discovered and also traces of embryonic eye structures. The masses of brain substance are scattered very irregularly through the tumor and at first sight apparently lawlessly. The size of the individual masses varies much, from small' islands of the tissue recognizable only with the aid of the microscope to relatively large areas easily visible to the naked eye. Some of the masses are bounded definitely on one side by a cavity lined by cubical epithelium (rudiment of ventricles and ependymal epithe-lium), and on another side by vascular connective tissue (brain-mem-branes?). Other portions of brain substance are found for which no ventricu]ar nor meningeal relations can be made. out. In places the lining of the cavities supposed to represent the ventricles is seen to be made up of low, clear, cubical epithelium, which can be followed as a definite lamina chorioidea epithelialis over the much branched and anastomosing papillary strands of vascular connective tissue which project into the cavity, forming a distinct plexus ehorioideus (Plate XXII, Fig. 13). No cilia could be made out, however, on any of the cells lining the cavities. In certain regions, instead of a lining with the characters just described, the tissue adjacent to the cavity resembles more closely that seen in certain regions in the embryo, for example that of the develo.ping corpus striatum and of the developing spinal cord. The ependymal epithelium is divisible into three distinct zones-an inner, middle, and external zone. In the middle zone of each cell is