Professor Karl Pearson, the eminent authority on biometrics, writes to Nature of May 6, inquiring where a number of medical journals, or certain years of such, can be found in England, stating that they have been looked for at the likely places and it is possible that they exist and have not been found. It seems a curious thing that London, with its library of the British Museum and all its other medical and general libraries, should lack copies of such widely quoted periodicals as Lo Spallanzani, the Archiv f. Psychiatrie u. Nervenkrankheiten for the eighties, the International Medical Magazine, etc. There seems also to be no library in London containing a complete set of university dissertations and degree theses. This last probably would be found to be the case also in many, if not all, of our American libraries, though there are opportunities occasionally of acquiring them at comparatively small cost. Many of these theses contain valuable matter or worked up summaries of our knowledge on their special subjects, and, while they are not absolutely necessary, they may be badly wanted at times. If any one occupied in research wishes to verify his references he needs to have all the conveniences for that kind of work, and, though bibliography in scientific papers may be easily overdone, the facilities for it should not have too many limitations.