791 
Shortly before we kad brought our experiments to a close, Linp- 
HARD‘) published an article, in which he reports the fluctuations of 
respiratory exchange in the different seasons, which according to 
him run parallel to the intensity of the sunlight. 
It seems to us however, that his values of the oxygen intake do 
not differ sufficiently and are too inconstant to warrant such a 
conclusion. 
For our determinations we used Zunrz and GeEpprErt’s?) method. 
The subject, whose nose is shut off by a spring-clip, breathes 
through a mouth-piece, corresponding by means of a T-shaped tube 
with two very mobile gut-valves, one of which transmits only the 
air taken in, the other only the air which is exhaled. The latter 
passes, without encountering any resistance worth mentioning, through 
a slightly aspirating gasometer, a constant fraction of the expired 
air being continually separated for gas-analysis by means of a special 
apparatus. Furthermore a supple pig’s bladder had been inserted 
between the valves and the gasometer. This highly facilitated expi- 
ration, as was apparent from the working-experiments to be discussed 
later on. — 
Outside air was supplied through a short and wide india-rubber 
tube, connected with the ‘valves. The room which faced the North, 
was constantly well ventilated through the open windows. 
We experimented every time under similar circumstances, 1. e. 
the experiments were made in the morning, always at the same 
hour, and with the same interval after breakfast. 
The breakfast varied for the several subjects, but for each indivi- 
dually it was the same. For a quarter of an hour before and during 
the experiment, the subject reclined in an easy chair, resting quietly. 
The temperature of the room was taken, the readings of the baro- 
meter and the sort of weather (misty, sunny, frosty ete.) were noted 
down. 
Likewise the respiration, the number of liters of air exhaled, and 
the time (in seconds) were recorded on a kymographion (Fig. 1). 
The time the experiment took us, was also registered by a tinte- 
keeper. Furtheron the relative moisture in the room was measured too 
as well as the temperature and the degree of moisture under the 
clothes. 
Our subjects were four adults, all of them employed every day 
1) J. LiNDHARD. Seasonal periodicity in respiration. 
Skandinav. Archiv. f. Physiologie XXVI p. 221. 
2) Maanus-Levy. Ueber die Grösze des respiratorischen Gaswechsels u. s. w. 
Pfltiger’s Archiv. f. die ges. Physiologie. Bd. 55. 1894, p. 9. 
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