According to statistics, it is estimated that 50 per cent of all cancers metastasize and that 4.77 per cent involve the central nervous system. I have been unable to ascertain if the percentage of metastases to the eye has been determined when the central nervous system is involved; it would be of interest to know. Winkleman and Eckle1have determined that about one half of the metastases of the central nervous system arise from primary cancers of the breast, lung and prostate, with the uterus next on the list of frequency. When the metastasis is by way of the lymphatics, the meninges are more apt to be involved. Retrograde extension, first emphasized by von Recklinghausen and later confirmed by others, is a frequent means of extension of cancer, and occurs more especially in organs having a venous pulse. Ewing thinks that the reason some organs are involved more fre