3OO L. H. HYMAN. 



All of the experiments on Planaria were performed at a 

 temperature of 20 C. and the oxygen in all cases is calculated 

 for this temperature. The results are given in cubic centimeters 

 of oxygen consumed per hour. The animals were not weighed 

 as the oxygen consumed per gram is of no importance for the 

 present experiments. For the benefit of those who may be 

 curious regarding this matter it may be stated that the normal 

 rate of oxygen consumption of this species under the conditions 

 of the experiments (worms of medium size, four to fourteen days 

 after feeding, temperature 20 C.) is about .20 cc. of oxygen per 

 gram per hour. 



2. Water. The water used in the experiments comes from a 

 well driven into the ground from the floor of the basement of the 

 laboratory. This water when it emerges from the taps is super- 

 saturated with air and also contains a considerable amount of 

 free carbon dioxide. It has a pH of about 7.3. On account of 

 the gas content the water is heated but not boiled and then 

 allowed to cool overnight before being used for experimental 

 purposes. Water so treated has a pH of 8.0 to 8.2. This is the 

 water regarded in the experiments as "normal" and the respira- 

 tion in such water is taken as "normal." The water is of course 

 thoroughly aerated before use, bringing the oxygen content up 

 to 6 to 8 cc. per liter. 



TABLE III. 



ANALYSIS OF THE WATER USED IN THE EXPERIMENTS ON Planaria. 

 All figures represent parts per million. Analysis made in 1922. 



Determinations as Hypothetical combinations. 



Iron Fe 0.2 Potassium nitrate 1.4 



Manganese Mn o.i Potassium chloride i.i 



Silica SiOa 7.8 Sodium chloride 7.6 



Nonvolatile 0.7 Ammonium chloride o.i 



Alumina AhOs ' 1.6 Magnesium chloride i.o 



Calcium Ca 49.2 Magnesium sulphate 22.1 



Magnesium Mg 16.7 Magnesium carbonate 41.5 



Ammonia NH 4 0.03 Calcium carbonate 123.0 



Sodium Na 3.0 Silica SiO2 7.8 



Potassium K i.i Alumina AhOa 1.6 



Sulphate SO4 17.7 Iron oxide FeaOs 0.3 



Nitrate NO 3 0.9 



Chloride Cl 6.0 



Alkalinity (methyl orange) .... 170 



Residue 193 



