18 J. WILLIAM BUCHANAN 



In C pieces the data show a marked increase in head frequency 

 in all experiments except one. On the basis of Child's conclu- 

 sions, this effect is interpreted as the result of the elimination by 

 the anesthetic of stimulation in the Y region. In C pieces in 

 water this stimulation inhibits the developmental processes 

 of the X region. Its elimination in chloretone removes to a 

 greater or less extent this inhibitory factor. The effect of the 

 removal of this inhibition is suffi.cient to obscure any direct 

 effect of the chloretone on Rate X. In the apparent exception, 

 series 2, the animals used were quite small, and consequently 

 their susceptibility to external agents was higher and the stimu- 

 lation of Y by section less than in older animals. Under such 

 conditions, a more striking direct effect on Rate X is to be ex- 

 pected. 



In B pieces the results may be regarded as intermediate be- 

 tween those in the A and C pieces. Changes in the head fre- 

 quency in the B pieces appear to depend in these data on the 

 concentration employed, the duration of the time of exposure, 

 and the size of the animals. Very high concentrations or long 

 periods of exposure bring about decreases as in series 3 and 

 series 5. Shorter periods of exposure and lower concentrations 

 bring about increases in head frequency as in series 1, 6, and 7, 

 or no change as in series 8 and 9. 



Oxygen consumption. The similarity of the head-frequency 

 results given in table lA to Child's results with KNC indicates 

 that the effect of chloretone on the stimulation of section is 

 similar to that of KNC. To test by actual direct measurements 

 whether or not chloretone does prevent the stimulation of the 

 pieces by section, the oxygen consumption of the pieces imme- 

 diately after section in water and in appropriate concentrations 

 of chloretone was measured. Table IB gives the complete results 

 of all experiments attempted. 



Pieces subjected to relatively strong solutions of chloretone 

 increase in weight during the period of exposure, and in order 

 to arrive at a more nearly correct measurement of their rate of 

 oxygen consumption per unit of weight it was found necessary 

 to weigh them before the tests. In no other of the anesthetics 



