Following my usual bent, I did not call at Koenigergratzerstrasse 70 as the Captain suggested. About three days passed and then I received a very courteously worded letter requesting me to call at my earliest convenience at his quarters as he had something of importance to tell me. I called. Koenigergratzerstrasse 70 is a typical Prussian building of administration. Solid but unpretentious, it is the very embodiment of Prussian efficiency, and like all official buildings in Germany is well guarded. The doorkeeper and commissaire, a taciturn non-commissioned officer, takes your name and whom you wish to see. He enters these later in a book, then telephones to the person required and you are either ushered up or denied admittance. When sent up, you are invariably accompanied by an orderly--it does not matter how well you are known--who does not leave you until the door has closed behind you. When you leave, there is the same procedure and the very duration of your visit is entered and checked in the doorkeeper's book. I was admitted immediately. After passing through three anterooms containing private secretaries not in uniform, I was shown into Captain von Tappken's private office. He wore the undress ranking uniform of the Imperial Navy. This is significant, for it is characteristic of all the branches of the Prussian Service to find officers in charge. The secretaries and men of all work, however, are civilians; this for a reason. The heads of all departments are German officers, recruited from the old feudal aristocracy, loyal to a degree to the throne. They find it incompatible, notwithstanding their loyalty, to soil their hands with some of the work connected with all government duties, especially those of the Secret Service. Though planning the work, they never execute it. To be sure, there are ex-officers connected with the Secret Service, men like von Zenden, formerly an officer of the Zweiter Garde Dragoner, but with some few exceptions they are usually men who have gone to smash. No active or commissioned officer does Secret Service work. Von Tappken greeted me very tactfully. This is another typical asset of a Prussian Service officer, especially a naval man, and is quite contrary to the usual characteristics of English officials, whose brusqueness is too well and unpleasantly known. After offering me a chair and cigars, Captain von Tappken began chatting. "Well, Doctor," he said, "have you made up your mind to enter our Service? For a man fond of traveling and adventure, I promise you will find it tremendously interesting. I have carefully considered your equipment and experience and find that they will be of mutual benefit." I asked him to explain what would be required of me, but he replied: "Before my entering upon that, are you adverse to telling me if you have made up your mind to enter the Service?" It was a fair question, and I replied: