Since obviously the utmost limits of these experiments had been reached with the descending experiments from 15 km. [49,200 ft.] without oxygen breathing, descending experiments with oxygen breathing were conducted from greater heights. In the experiments, the following experimental procedure was chosen: ascent to 8 km. [26,300 ft.], remaining there 5 to 10 minutes with oxygen breathing; then turning on the oxygen blower explosive decompression to a predetermined altitude; 10 seconds waiting time (experiments from 17 [55,800 ft.] and 18 km. [59,100 ft.], altitude without waiting time) and descent at sinking speed. In order to imitate the perpendicular body position as occurs in suspension in a parachute harness, the experimental subjects had to stand during the experiments since suspension was not possible in the small decompression chamber. In the descending experiments from 15 km. [49,200 ft.] altitude there was no altitude sickness or only a slight temporary kind. In the further descending experiments, the following results were obtained (Table 4): [page 19 of original] Table 4.—Descending experiments with oxygen breathing Unconsciousness │ From— │ Recovery of after— │ │ consciousness after— │ │ 23 sec. = 15.75 km. │16 km. [52,500 ft.] │2 min. 35 sec. = 13.55 │ │km. [51,660 ft.] │ │ [44,460 ft.] 10 sec. = 16.8 km. │17 km. [55,800 ft.] │3 min. 50 sec. = 13 km. [55,120 ft.] │ │ [42,700 ft.] 7 sec. = 17.9 km. │18 km. [59,100 ft.] │10 min. 35 sec. = 8.5 km. [58,740 ft.] │ │ [27,890 ft.] Thus it was shown that unconsciousness developed relatively early in spite of oxygen breathing, while the following convulsive stage ran its course in a much less severe form than in the experiments without oxygen breathing. Primarily spasmodic convulsions with only occasionally light tonic convulsions developed. Breathing paralysis never set in and upon recovery of consciousness the experimental subjects were again completely in control of themselves. The markedly quick development of unconsciousness was caused by the fact that the subjects were standing during the experiments (to be considered in comparison with the corresponding times in the falling experiments with oxygen breathing). Descending experiments from still greater altitudes were not undertaken, since in practice there is no need to escape from such altitudes with open parachute and thus to expose oneself to the danger of severe freezing. _3. Falling experiments without oxygen_