RESPIRATORY DIFFERENCES. 



387 



beginning and at the end of each experiment. The former is 

 determined by calculation from the control blanks, and the 

 latter by calculation from the analysis of the portions .4 plus B 

 of the experimental tubes, the contents of A plus B and C plus 

 D being known. When calculated in this form, the difference 



TABLE II. 



RELATIVE CARBON DIOXIDE PRODUCTION OF APICAL AND BASAL PIECES OF THE 

 BODY OF THE SPONGE Grantia, IN TERMS OF TIME REQUIRED 



TO CHANGE PHENOL RED FROM pH 8.0 TO 7.5. 

 h.. hours; m.. minutes. 



betwtvn tin- two values gives the oxygen consumed l>y tin- 

 pieces. This divided by the weight and then by three (as each 

 experiment ran for three hours) gives the oxygen consumed per 

 gram of weight per hour. The figure thus obtained seems a 

 little low as compared with the respiration rate of other animals 



