Perhaps I stared at them a little, for the old man, noting my interest, remarked proudly, "Yes, I have contributed much glory to the race and our group,--one hundred and forty-seven children,--one hundred and four of them sons, fifty-eight already of a captain's rank, and twenty-nine of them colonels--my children of the second and third generation number above two thousand. Only three men living in Berlin have more total descendants--and I am but seventy-eight years of age. If I live to be ninety I shall break all records of the Eugenic Office. It all comes of good breeding and good work. I won my paternity right, when I was but twenty-eight, just about your age. If you pass the physical test, perhaps you can duplicate my record. For this early promotion you have won qualifies you mentally." Astonished and alarmed beyond measure I could find no reply and sat staring dumbly, while Herr von Uhl, beginning to speak of chemical matters, inquired if I had any preference as to the problem I should now take up. Incapable of any clear thinking I could only ask if he had any to suggest. Immediately the old man's face brightened. "A man of your genius," he said, "should be permitted to try his brain with the greatest problems on which the life of Germany depends. The Staff discussed this and has assigned you to original research for the finding of a better method of the extraction of protium from the ore. To work on this assignment you must of necessity share grave secrets, which, should they be disclosed, might create profound fears, but your professional honour is a sufficient guarantee of secrecy. In this research you will compete with some of the most distinguished chemists in Berlin. If you should be successful you will be decorated by His Majesty and you will receive a liberal pension commensurate with the value of your discovery." I was profoundly impressed. Evidently I had stumbled upon something of vital importance, the real nature of which I did not in the least comprehend, and happily was not supposed to. The interview was ended by my being entrusted with voluminous unpublished documents which I was told to take home and study. Two armed men were ordered to accompany me and to stand alternate guard outside my apartment while I had the documents in my possession. ~3~ In the quiet of my new abode I unsealed the package. The first sheet contained the official offer of the rewards in store for success with the research. The further papers explained the occasion for the gravity and secrecy, and outlined the problem. The colossal consequence of the matter with which I was dealing gripped and thrilled me. Protium, it seemed, was the German name for a rare element of the radium group, which, from its atomic weight and other properties, I recognized as being known to the outside world only as a laboratory curiosity of no industrial significance.