694 



OSTERHOUT RESPIRATORY APPARATUS 



and it is in this form that I have used it in calculating the weights 

 of carbon dioxide produced by sea anemones. Thus in one instance 

 a sea anemone weighing 0.5 gm. brought about the necessary color 

 change in the indicator in 424.8 seconds. This animal must, there- 

 fore, have produced 1,283.5/424.8 or 3.0+ hundred-thousandths of a 

 milligram of carbon dioxide per second. Another one also weighing 

 0.5 gm. brought about the same change in 420.4 seconds and by a 

 similar calculation can be shown to have produced 3.1 — hundred- 



0.020 



aoi5. . 



aoio. . 



4 



-aoos.. 



10 15 



MoO.0(U> m^. CQt per second 



Fig. 1. 



thousandths of a milligram of carbon dioxide per second. The two 

 animals together changed the indicator over the requisite range in 

 213 seconds which when used as a basis of calculation yield 6.0 -f- 

 hundred-thousandths of a milligram of carbon dioxide per second 

 or almost exactly twice that of the sea anemones taken separately. 

 Thus the proposed formula afTords an easy means of calculating the 

 absolute amount of carbon dioxide excreted when the time of the 

 indicator change and the apparatus constant are known. 



