528 A. FRANKLIN SHULL 



The control started with 6.81 cc. of oxygen per Hter in the un- 

 treated water (a) . Upon the addition of food (manure scum) the 

 oxygen content fell to 5.82 cc. per liter (f) ; while after standing 

 a day it further fell to 4.13 cc. per liter (g) . 



Assuming that the oxygen content of the water in both halves 

 of the experiment changed uniformly during the twenty-four 

 hours in which eggs were being laid, the mean oxygen content 

 of the oxygenated water was 



7.58 + 8.35 



= 7.965 cc. per liter; 



while the mean oxygen content of the control dishes was 



5.82 + 4.13 



= 4.975 cc. per liter. 



Absolutely, the difference between experiment and control was 

 about 3 cc. per liter. Relatively, the oxygenated water contained 

 60 per cent more oxygen than did the untreated water. 



Test No. 2 (table 3) is less complete than the foregoing, but 

 indicates approximately the amount of oxygen involved in the 

 60 per cent oxygen experiments. No test of untreated water at 

 the beginning of the twenty-four hour period described was made 

 and no food was added. It is likely that under these circum- 

 stances the untreated water exposed to air would not lose oxygen, 

 but might gain it, so that the average content of such water dur- 

 ing the twenty-four hours would be not greater than 7.88 cc. per 

 liter (c). The water shaken with 60 per cent oxygen must have 

 averaged about 15 cc. per liter (a and b), or nearly double the 

 content of the untreated water. This test was not very relevant, 

 but since the comparison was to be made between the 40 per cent 

 oxygen experiments and those in which green food was used, a 

 more accurate test of the 60 per cent oxygen experiments was not 

 made. 



Tests 3 and 4 have little bearing on the experiments, and are 

 recorded for whatever interest may attach to the solubility of 

 oxygen at higher pressures. 



