The importance of noting the nitrogen output during this period of undernutrition led us to emphasize especially to the squad the necessity for the complete collection of the urine for the entire period of the research, or at least this was held up as an ideal. Each man was told that the best and most perfect picture of the balance of income and outgo of nitrogen could be obtained only by the faithful collection of all the urine. The fact that we were able to secure practically every day 24hour quantities of urine for 12 to 25 men during a period of 3 to 4 months is indubitable evidence of the fidelity of the men in this rather tedious and embarrassing part of their cooperation. It involved in-many instances carrying special containers or in an emergency purchasing special bottles, but in spite of all these inconveniences the squad were extraordinarily faithful in living up to the ideal of collecting the entire amount of urine.

Usually the experimental day was ended, so far as the collection of urine was concerned, from 5 to 6 o'clock in the morning, when the men appeared for weighing and for the measurement of the gaseous metabolism. The entire collection of urine was mixed in one 24-hour specimen, which was carefully measured and checked by a second observer. A 130 c.c. sample was then bottled, carefully labelled with dates, times, etc., and shipped in special shipping cases, with provisions to avoid breakage and, when necessary, freezing. Notwithstanding our care, one shipment was lost from freezing. After this happened, the original cases containing the urine bottles were packed inside of a larger case and the intermediate space filled with sawdust.