This was a large building with an extensive garden at 38 Nussbaum Allee, Charlottenburg. The appellation “Nussbaum Allee” distinguished it from the other houses, of which there were four, if I am not mistaken. I forget their names, however, with the exception of “Linden Allee.” There were two classes of patients, whose food and accommodation differed according to the amount they paid, or which was paid for them by the British Government through the American Embassy. First-class treatment cost at that time twelve marks per day exclusive of medicines and special treatment. Without exception the expense had to be defrayed by the patient himself. In the second-class eight marks per day was charged. Neither class could expect private bedrooms for this, except where infectious ailments or other medical reasons made separate rooms imperative. I had offered to pay my own expenses, to avoid delay by having my case referred to the American Embassy. It was a matter of indifference to me what class I was put into. The points of comfort I was looking for were easily opened windows, etc. I liked fresh air at any time, but now was particularly impressed by a theory of mine, that fresh air could be admitted in sufficient quantities only by windows not too high from the ground and large enough to admit, or rather to give exit to, a fairly bulky man. The windows looked all right, but, from my point of view, they were _not_. They had diamond panes set in cast-iron frames; and even if they opened, a dog could not have got out of the aperture. All the corridor doors were kept constantly locked. There was no passing from one part of the building to another without the help of a warder or a nurse. The idea of having to sleep in the same room with six or eight people, one or two of them seriously ill, did not appeal to me. One of them was always sure to be awake at night. Straightway I applied for first-class treatment, for this would get me sent to the “Linden Allee Villa,” where these lunatic-asylum precautions would probably be absent. I was taken there in the course of the following morning. My assumption proved correct, for things were different. Twelve patients nearly occupied the available accommodation. The staff consisted of only a nurse and three servant girls, and no military guard was about the place. The biggest bedrooms contained three beds. A garden surrounded the house, accessible through at least three doors and a number of windows of the ordinary French pattern. A low iron railing separated the garden from the streets, which in this part of the town were very wide, and which frequently had two causeways, lined with trees, and divided by stretches of lawn and thick shrubbery. Not far from “Linden Allee” a big artery ran right into Berlin. CHAPTER IV PLANNING THE DETAILS The outlines of my plan of escape had been conceived almost a year before in Ruhleben, and had remained unaltered.