1915] SPOEHR—RESPIRATORY ACTIVITY 375 
production between day and night grow less as the food material 
is used up, and as the gaseous exchange becomes more difficult, 
because the shriveled outer layer forms a protecting coat. The 
amount of carbon dioxide evolved from onions in which the outer 
layer is dry and contains little food material is very small. 
Day rate 
Night rate.’ TS: 
(2) In the next experiment (p. 376) 75 wheat seedlings were 
used. This was started after the seedlings were 24 hours old, and 
ran from February 11 to 24. The results are given in table II and 
Day rate 
(3) In the experiment tabulated on p. 377, 70 wheat seedlings 
were used, which ran from April 29 to May g._ Several of the seeds 
were infected with fungus, wherefore the experiment was not run 
longer. The results are given in table III and fig. 4. 
Day rate 
Night rate 
(4) The deionizing apparatus was used in the next experiment 
(p. 378), and 70 wheat seedlings were used. The experiment ran 
from April 14 to April 25. Unfortunately, however, on the night of 
April 17-18 the pump was out of order, and the determination for 
that period is not reliable. The results are given in table IV 
and fig. 5. 
(5) Here also (p. 379) the deionizing apparatus was used, with 7o 
wheat seedlings in the flask. The experiment ran from March 13 to 
Day rate 
= 1.001. 
20. The results are given in table V and fig. 6. 
(6) The deionizing apparatus was used here (p. 380), with 70 
wheat seedlings. The experiment ran from May 11 to 22. The 
Day rate 
Night rate 
(7) In this experiment (p. 381) the carbon dioxide was deter- 
mined for three hour periods, and 200 wheat seedlings were used. 
The experiment ran from May 25 to 27, and the deionizing apparatus 
was not used. The results are given in table VII and fig. 8. At this 
time of the year the night time must be considered as falling within 
results are given in table VI and fig. 7. =1.015. 
