EXPERIMENTAL DATA OF DETERMINATIONS. 



57 



TABLE 31. Evolution of CO* at higher temperatures. Opuntia versicolor. 



All of these determinations were made in New York in 1912 from material sent from Tuc- 

 son. In all three series the material was treated in a similar way. Determinations were 

 made only after the specimens had been for at least 2 hours under the temperature under 

 investigation. The actual determinations were made in half-hour periods, but have been 

 calculated in terms of whole hours for the sake of comparison with the standard of milli- 

 grams CO-2 per hour, per gram fresh weight, which has been used throughout. 



TABLE 32. Intramolecular respiration. 



The material used was 15 joints of the previous season's growth of Opuntia versicolor 

 having a fresh weight of 336 grams. Respiration was observed in air and in pure hydrogen 

 at 20 to 21 and 34 to 36 C. The experiment was carried on at New York, April 1 to 3, 

 1912, with material sent from Tucson, Arizona. 



